digest - sabita – excellence in bituminous products · 2010. 2. 12. · bitumen price index (bpi)...
TRANSCRIPT
1
DigestPublished March 2003
2
Considerable effort has been taken to ensure the accuracy andreliability of the information contained in this publication. However,neither Sabita nor any of its members can accept any responsibilitywhatever for any loss, damage or injury resulting from the use orimplementation of this information.
The views and opinions expressed in this publication are those of theauthors, and do not necessarily reflect the views of Sabita or any ofits members
Vision
Mission
3
Sabita’s plans and actions are consistent with good corporatecitizenship to underpin its dealings with government, and toassist its members.
Sabita will:
• Advance best practice in southern Africa with due regardto worker health and safety, as well as the conservation ofthe environment;
• provide education and training schemes to develop skillsand competencies that are sustainable and aligned tonational goals and frameworks; and
• engage government to promote the social and economicvalue of road provision and efficient delivery by state roadorganisations
4
Contents
Foreword . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9Piet Myburgh, Executive Director, Sabita
1. Industry Overview 11
Theory and fact about SA’s public infrastructire. . . . . . . . . . 13Don Ross, Deputy Dean, Faculty of Commerce,University of Cape Town
Sabita’s Infrastructure Development Assessment Project . . . 20Don Ross, Deputy Dean, Faculty of Commerce,University of Cape Town
Wake-up call to local government . . . . . . . . . . . . . . . . . . . 28Daniel Mashatola, Convenor,Sabita’s Advisory Group On Development
Roads and the civil engineering industry . . . . . . . . . . . . . . . 33Pierre Blaauw, economist, SAFCEC
SANRAL clusters. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37Dennis Rossmann, Materials Engineer,SANRAL Eastern Region
Road budgets and managerial skills . . . . . . . . . . . . . . . . . .41Wynand Steyn, Manager, CSIR TransportekEduard Kleyn, Consultant to CSIR Transportek
Quad Squad social responsibility programme . . . . . . . . . . . .44John Onraët, Director, Much Asphalt
5
2. Human Capital Development 47
Aspects of life-cycle learning . . . . . . . . . . . . . . . . . . . . . . . 48Emile Horak, Head of Department, Civil andBiosystems Engineering, University of Pretoria
SANRAL Chair: Overview of 2002 . . . . . . . . . . . . . . . . . . . .58Kim Jenkins, Head, SANRAL Chair in PavementEngineering, University of Stellenbosch
The Asphalt Academy in 2002 . . . . . . . . . . . . . . . . . . . . . . 64Les Sampson, CEO, Asphalt Academy
Re-structured Society for Asphalt Technology (SAT) . . . . . . 67John Onraët, President, SAT
CAPSA’04 preview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73Arthur Taute, Chairman, CAPSA’04
Road Pavements Forum embraces strategic issues . . . . . . . 75
3. New Developments 79
Bitumen Price Index (BPI) adopted . . . . . . . . . . . . . . . . . 80Piet Myburgh, Executive Director, Sabita
Review of Interim Technical Guidelines (TG2) . . . . . . . . . . 84Fenella Long, Researcher, CSIR TransportekHechter Theyse, Researcher, CSIR Transportek
Cold-mix paving blocks . . . . . . . . . . . . . . . . . . . . . . . . . . 88Kim Jenkins, Head, SANRAL Chair in PavementEngineering, University of Stellenbosch
International Conference on Asphalt Pavements (ICAP) .. . . 90Morris de Beer, Project Manager, CSIR Transportek
Heavy vehicle simulator tests on TR11/1 . . . . . . . . . . . . . . 97Elzbieta Sadzik, Materials Chief Engineer, GautransMervyn Henderson, Chief Engineer, Materials Design, PAWC
Update on the RPF task team on binder distributors . . . . . . 101Trevor Distin, Chairman,RPF task team on binder distributors
6
4. Best Practice 107
Laboratory proficiency scheme a must for SA. . . . . . . . . . 109Les Sampson, Convenor, RPF Task Team onLaboratory Accreditation
Options for classification and disposal of bitumen waste . . . 112Mannie Levin, Senior Geohydrologist, Africon
Prefabricated bitumen rubber bound road patch . . . . . . . . 120Michael Church, Project Engineer,AJ Broom Road Products
Surface enrichment sprays. . . . . . . . . . . . . . . . . . . . . . . . 123Trevor Distin, Marketing Manager, Colas SA
Bitumen based precoating fluid for surface dressing . . . . . . 131Kobus Louw, Research and Development ManagerColas SA
Natref production after expansion programme . . . . . . . . . . 134Anelize Loftie-Eaton, Bitumen SpecialistSasol Oil R&D
Estimating the compaction time for hot-mix asphalt . . . . . . 139Julian Wise, Technical Director,Zebra Bituminous Surfacing
Micropave: a viable off-the-shelf surfacing solution . . . . . . 145Andrew Thompson, Director, Zebra Bituminous SurfacingJohn Onraët, Director, Much Asphalt
Author Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 149Sabita/Asphalt Academy Manuals . . . . . . . . . . . . . . . . . . .151Sabita Video Series. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152
7
8
Foreword
As in the past this issue of the Digest underlines the wealth of our roadssector in terms of human capital and experience — both essentialingredients of a vibrant industry. The industry’s strength is reflected inthe fact that this capacity has not only survived, but also grew duringsome decades of curtailed investment in road infrastructure provisionand maintenance.
At present there are signs of prospects for growth in the industry, andno doubt the mobilisation of the full potential of the industry will ensurethat the challenges associated with an upturn in activity will be met in aresponsible and cost efficient manner.
We remain most appreciative of the willingness of the authors tocontribute and unselfishly share their experiences with their colleagues.Once again, several innovative and positive developments have laid thegroundwork for a comprehensive Sabita Digest. The publication aims toprovide a bird’s eye view of the environment of the blacktop industry’sand its proactive role in facilitating global standards of education,training, technology and infrastructure delivery, while at the same timehaving a concern for the developmental needs of the southern Africanregion.
9
Piet MyburghExecutive Director
Sabita
10
11
1IndustryOverview
12
Roads and the ‘shadow line’
In early 2001, Sabitacommissioned and funded acomprehensive report on “The
under-provision andunder-capitalisation of roadmaintenance, rehabilitation andupgrading in South Africa’.Dubbed ‘the Ross Report’ by theSA media, after its principalauthor, the document has beenwidely cited and quoted innewspapers, television, parliamentand public meetings since itsrelease.
At the core of theReport was theominous concept ofthe ‘shadow line,’ thequantitative point pastwhich the backlog inmaintenance becomesso large as to be self-reinforcing, with roadsdeteriorating anddepreciating too fastfor a relatively stablebudget to keep pace.
Some other Africancountries, including
Kenya and Zambia, crossed theirown shadow lines some years ago,and the result can now beobserved in the generallydevastated public infrastructure.This occurred because soundroads are a prerequisite for propermaintenance of and reinvestmentin the structures they support,including schools, hospitals, andbusiness parks. It is vital thatSouth Africa learn from thesesad experiences of others, andinvest enough in roads now tostay on this side of its shadowline.
13
Infrastructure in SA:Using scarce resourceswisely
Don RossDeputy Dean
Faculty of EconomicsUniversity of Cape Town
Part One: Theory and fact about South Africa’spublic physical infrastructure
Unpaved and potholed urban roads, Philippi, WesternCape
However, it must do this with arealistic appreciation of available,scarce resources. Generating largebudget increases throughsubstantially increased taxation,either of the general public or ofmotorists through increasedlicense fees and petrol levies, isultimately self-defeating, sincethis competes with the veryprivate investment needed to growthe resource base in the firstplace.
It is no use robbing Peter to payPaul. The crucial prerequisite foravoiding our shadow line istherefore the achievement ofmaximal - which, by reference tothe status quo, means massivelyimproved - efficiency in usingresources not enormously greaterthan those already deployed.
The Ross Report makes twoprincipal recommendations foractive measures by which theefficiency of road maintenance andconstruction in South Africa couldbe enhanced. The primarymeasure is a reform of fiscalfederalist arrangements - that is,of the financing and budgeting ofprovincial and municipalgovernments - to incorporate anincentive-aligning capital-granttransfer mechanism (CGT).
The point of such schemes, whichhave become common in otherfederal countries, would be tochange the incentive landscape inprovincial and local governmentsso that funds raised for infrastruc-
ture were actually spent oninfrastructure, but without theneed for continuous, impractical,expensive and demoralisingoutside monitoring of officials.
Capturing major unrealisedefficiencies in infrastructuredevelopment likely requiresimplementation of such amechanism. However, getting toits implementation will involvesubstantial political coordinationamongst numerous stakeholders,and a good deal of advancetechnical work.
Sabita is committed to driving theprocess of bringing CGT to SouthAfrica by lobbying cabinet on theneed for it, by publicly explainingit in the media, and by facilitatingthe technical economic and legal
analysis that will be the basis fordesigning it. The ambitiousness ofthis goal makes its achievement aproject of some years. However,this does not imply that we shouldor must stand idly by in themeantime, watching the shadowline approach. The second mainmeasure suggested in the RossReport can be pursued much moreimmediately and directly; andSabita, with partners, is alreadypursuing it.
The second policy thrust is todevelop an Opportunity ValueAssessment (OVA) tool forprioritising possible infrastructureprojects. What I will do here isexplain what this is, why SA needs
14
The point ... would be to change the incentive landscape so thatfunds raised for infrastructure are spent on infrastructure.
it, and what Sabita and itsassociates are now doing aboutproviding it.
Cost-benefit analysis,infrastructure prioritisation,and the special problems of SA
Economists have devised anextensive range of devices forassessing the comparative valuesof public capital-investment ideas.All of these are variants andspecifications of generic
cost-benefit analysis (CBA). Withrespect to roads in particular,there is no shortage ofsophisticated models designed forcalculating economically rationalapproaches to construction andmaintenance.
The most complete of these is theHighway Design and MaintenanceStandards Model (HDM),developed and regularly updatedby the Transportation Departmentof the World Bank. Unlike genericCBA models, HDM is sensitive tothe special problems of developing
countries. Such countries typicallyface imperatives to addressdestabilising levels of poverty,along with local pockets - oftenlarge ones - of severe capitalabsence.
This is certainly true of SouthAfrica. HDM is built to allowspecific political/social priorityweightings to be ‘plugged on’ asmodules, which can either feedback into the general model, or beapplied to modify its output. In
South Africa at themoment, projectplanners typicallycombine some use ofHDM - sometimesformal and explicit,sometimes indirectand approximate -with local variationsdriven by the budgetmodels and politicaldynamics peculiar totheir jurisdictions.
For example, supposeone is choosingbetween two possible
road projects that a ‘raw’ HDM toolfinds to be of roughly equal valuefor capital-asset support anddevelopment. Suppose further,however, that one of theseprojects could keep more labourbusy in the short run in an areawhere new labour-intensiveindustrial initiatives are planned,but where volatile workforcemigration is a feature of themarket, as it is in South Africa. Aproject prioritising model couldeither build this consideration intothe input to HDM and feed itthrough, or plug a module for
15
Storm water drainage problem at Brown’s Farm,Western Cape. Note pothole in foreground.
optimising labour-distributionstability onto the output side ofthe raw HDM analysis. HDM-styleplanning of both sorts isextensively used throughout thedeveloping world, as well it shouldbe.
Before I now go on to point outproblems with this approach, letme first be clear that someself-conscious modelling, howeverimperfect, is greatly preferable tonone. Furthermore, if locallydriven modules are going to beplugged onto more generic oneslike HDM, then it is much betterthat local authorities, rather thanmore distant ones, build thesemodules. We therefore do notencourage abandonment of orcomplaining about currentpractices until something moresystematic is actually in place. Weaim to build that more systematicsomething.
But why do we need a new tool inthe first place? The problem is thatSouth Africa faces some specialconstraints that are shared by afew other developing countries(e.g., Brazil and parts of India),but are unusual in Africa. First,South Africa competes with Brazilfor the dubious distinction ofhaving the world’s highest ‘GINIcoefficient’. This is the economist’sstandard measure of internalwelfare inequality; the higher acountry’s GINI, the greater itsdifferences in income levels asbetween large groups of itspeople.
Very poor countries, in whichalmost everybody is poor, canoften have quite low GINIs. Richcountries vary substantially intheir GINIs, but this frequentlydoesn’t matter much to plannersof public infrastructureinvestment. The wealthiestcitizens in such countries typicallybuy themselves out of the relevantservice sectors altogether, so thatlarge-scale public works servicethe same middle class whosetaxes mainly finance them. Ineither of these circumstance - highpoverty but low GINI, or lowgeneral poverty - purely politicalregional considerations are oftenall that are left out of standardcost/benefit analyses. Thus, inthese cases, developing ad hocplug-in modules and leavingtechnical experts large discretionwithin general budget constraintscan be the best solution.South Africa, however, fits into
neither of these baskets. As notedabove, South Africa’s GINI isenormous. It combines third-worldpoverty levels with a significantmiddle class and substantialfirst-world infrastructure,concentrated in parts of largecities. This raises two specialproblems.
First, estimates of the comparativevalues of infrastructure projectsare often intensely sensitive towealth effects. Roads, inparticular, derive much of theirvalue from their contributions tothe values of other assets, such as
16
South Africa competes with Brazil for the dubious distinction ofhaving the world’s highest ‘GINI coefficient’.
schools, hospitals and businessconcentrations that they makepossible; and then these assets inturn feed wealth-creatingproductivity. It is far easier toefficiently build such assets fromalready-existing bases than fromconditions of acute capitaldeprivation.1
Imagine, for example, that youare trying to choose between aroad that services a smallconcentration of tourist facilitiesand one that will enable ruralfarmers to drive, instead of walk,their vegetables to a mainhighway. The short-termcapital-asset potential of thefarmers is so small on margin thata standard CBA instrument willnever tell you to favour their roadunless your plug-on module isspecifically designed to swamp theefficiencies the general model issupposed to measure. But thisimplies that your ad hoc plug-onis doing all the work and yourmodel isn’t doing any!
National Treasury
The point here is certainly notthat you should automaticallysuppose that the farmers havethe priority call on infrastructurefunding just because they’repoorer. Following this sort ofreasoning in South Africa wouldbreak the national treasury longbefore most poor people could besignificantly helped; it wouldamount to trying to finance alldevelopment out of public funds,which is patently impossible.Rather, the point is that SouthAfrica’s large GINI tends toundermine current attempts tomake infrastructure project
prioritisation at all systematic. Tothe extent that this happens,every decision risks turning into apure political accident.
Furthermore, where politicalauthorities leave ‘fine details’ upto technical experts - for the bestof reasons - the net result is thatfundamentally political decisionsget made by people whose job isspecifically not to have to makesuch decisions. This places anonerous burden on them, andgenerally impedes efforts toachieve rationality - whether‘rationality’ is thought of inmarket-driven or planning terms -in resource allocation. This is the‘wealth effect’ problem.
I said above that South Africa’sspecial circumstances create twogeneral problems where infra-
17
Road deterioration, no sidewalks inSoweto
structure prioritisation isconcerned. I have just describedthe first one. Here is the secondone. ‘Development’ is, in the longterm, all about moving resources,including human resources, fromareas where they are inefficientlydeployed to areas where they canbe more efficiently used.Practically, this typically impliesshifting labour from rural to urbanconditions as capital stockaccumulates - a very ‘classical’picture, which generic CBA modelsencourage.
However, because South Africa’smost efficiently placed capital ishighly efficient by developingworld standards but also thin by
first-world ones, there is constanthigh risk here of shiftingpopulations from rural to urbanareas too quickly. In some sense,all South African planners havealways been acutely aware of this.Apartheid-era planners certainlywere, but their situation washopelessly complicated bystruggles between economicimperatives for moving labour, onthe one hand, and long-termpolitical goals that were bothmorally odious and rationallyimpossible, on the other hand.
Unfortunately, we cannot escapefrom these complications by sheerwillpower and better intentions. Itis possible to depopulate ruralareas at an unsustainably rapidrate through over-concentration ofnew capital reinvestment in
existing efficiencies, just as it isalso possible to misestimate in theopposite direction and break thepublic bank while discouraginglong-term growth. My point here,as before, is that the balance is anunusually fine one in SouthAfrica’s circumstances, one hardfor either markets or planners tofind. To some extent, plannershave no practical choice but to tryto find it. But then, where ad hocassumptions must do almost allthe work relative to moresystematic models, we are relyingentirely on the hope that errorswill cancel out.
One additional point is particularlyrelevant to the current framework
in which infrastructure planning isdone in South Africa. Because ofthe country’s high rate of formalsector unemployment, projects areoften evaluated with respect to theextent to which they ‘producejobs’. Discussions in these termsoften reflect basic economicconfusion.
‘Jobs’ are not assets in a directsense. The distribution ofemployment opportunities at anyone place and time is a function ofthe overall allocation of capitalassets. To the extent that thisoverall allocation is inefficient,creation of jobs on one projectmay block creation of more jobssomewhere else. Adding ‘jobcreation’ to a set of otherdesiderations in the constructionof a plug-on module to a CBA
18
Creation of jobs on one project may block the creation of morejobs somewhere else.
instrument thus confuseswhatever else is being directlymeasured by that module,encouraging double-counting ofsome potential efficiencies andunder-measurement of others.
This is in no way to suggest thatreduction of unemployment isunimportant. Rather, it is a pointabout the way in which thecontribution of infrastructuredevelopment to that goal iscalculated. Since employmentdistribution is a function of generalequilibrium, but since values in adhoc plug-ons to modelsnecessarily reflect politicalweightings, miscalculation in theseterms typically incorporatesunintended political decisionsabout the importance ofemploying one group of people, inone place, rather than anothergroup in another place. It seems
particularly inappropriate thatmodelling practice may implicitlyleave these political decisions totechnical experts rather than tothe political authorities whose jobthey are.
In the article above I havedescribed the theoretical andnormative background to Sabita’songoing campaign as a SouthAfrican development partner. Inthe next article, I will describe theactivities of that campaign itself:the Sabita InfrastructureDevelopment Assessment Project(SIDAP). �
1 Economists once thought otherwise; and this ledmodels of third-world development during the threedecades after World War II to be very optimistic.What is being assumed in the present discussion iscalled, for those interested in its relation toeconomic theory, an endogenous growth model.Most development economists now believe thatsuch models are usually truer to the facts.
19
Ihave now stated the case fortrying to develop a moresystematic set of project
prioritisation tools customised forSouth Africa. This is the aim of theSabita Infrastructure DevelopmentAssessment Project (SIDAP),which was launched in August2002. How is it to be achieved?There is, unfortunately, no magicformula for the exercise that canbe devised from theory at a deskand then carried out into the field.Development of a SA-specific
instrument requires a feedback-driven process, wherein generaleconomic knowledge is used toselect assets for value-measurement, thesemeasurements are tested inincremental models, and themodels are then themselvestested against outcomeprojections.
Theory and empirical measure-ment can thereby work in tandemuntil an instrument that satisfiesboth technical criticism andcommon-sense political-economicjudgement ‘on the ground’emerges. Furthermore,simultaneous work at several test
sites is necessary. We can onlyknow that we are working towardsa model of suitable generalitywhen the results of its applicationto various locations and possibleprojects show convergence.
In addition, tool-development atmultiple sites permits the use ofcomparative sensitivity analyses.The idea here is as follows. SouthAfrica’s provinces and regions arenot all alike, and any model that
builds in too many generalassumptions about them will tendto lead us back to the problemwe’re starting with. The way toavoid this is to systematicallycompare locally derived models asthey develop, in search ofmeasurement variables that showup as recurrently dominant. Thissort of analysis is what much ofquantitative developmentmicroeconomics is about; and it iswhat we need more of in SouthAfrica if we wish to spend existingresources for public infrastructurebuilding more efficiently. To theextent that we know whichparticular variables in SA producehigh variance, over and overagain, in soundly projected capital
20
Infrastructure in SA: Using scarceresources wisely
Part Two: The Sabita InfrastructureDevelopment AssessmentProject (SIDAP)
Don RossDeputy Dean
Faculty of EconomicsUniversity of Cape Town
The creation of a SA specific instrument requires a feedbackprocess to select assets for value-measurement.
outcome-values, then we will havetruly enhanced our understandingof how to evaluate infrastructuredevelopment proposals here,relative to one another.
SIDAP involves collaborationamongst a number of interestedagencies. In particular, siteselection and access call heavilyon existing local knowledge basesand experiences with project ideasand modelling histories. Much ofthis knowledge lies with the SouthAfrican National Roads Agency(SANRA) and its officials, withmunicipal planners and managers,and with provincial ministries.
Expertise in quantitativedevelopment microeconomics, asexplained above, is the other vitalcomponent, and this obviouslycannot be had for free.Sabita hasthereforecontributed sub-stantial financialresources to hiringsuch expertise,about which I willsay more below.This partnershipbetween existingknowledge andcommitment toimprovement, bySANRA and bymunicipal andprovincialauthorities, andtechnical skillswhose deploymentis funded bySabita, is the core of SIDAP.
On October 2, 2001, a
team from Sabita met with theDirector of SANRA, Nazir Alli, anddiscussed the possibility ofcooperating on focused fieldresearch intended to refine anOpportunity Value Assessment(OVA) instrument - the target ofthe descriptions and explanationsabove.
Mr. Alli expressed strong interestin such research. Sabita alsobriefed the ParliamentaryTransport Committee and receivedthe enthusiastic support of it andits Chairman Jeremy Cronin. Thesame view was indicated by theWestern Cape Transport Ministryofficials and technical planners, towhom the SIDAP team will soonbe presenting a detailed proposalfor collaboration on a site in thatprovince.
At the October 2001 meeting, andin a follow-up memorandum,Sabita suggested to the Director ofSANRA that three sites be selected
21
Storm and waste water runs freely down the side of thiskerbless Soweto street
for initial, roughly simultaneouspilot-studies. We consultedextensively with SANRA’s PierreCronje in Kwa-Zulu Natal, andwith other experienced infra-structure planners and facilitatorsconcerning site-selection there.The two sites at which work beganin August 2002 and will continuefor at least the next three yearsare uMkhanyakude (DistrictCouncil 27) in north-eastern KZN,and the Oliver Tambo District inthe southeastern-most part of theEastern Cape. As noted above, itwill shortly be proposed to theWestern Cape Ministry ofTransport that it participate as aSIDAP partner on a third site.
Explaining our reasons for havingchosen uMkhanyakude and OliverTambo as pilot sites is a usefulway of providing insight into what
SIDAP will actually do. Let mestart with uMkhanyakude. It is alarge rural area nestled betweenthe Indian Ocean and theMozambique and Swazilandborders, named for the ‘fevertree,’ (Acacia Xanthophloea) agreen-bark-coloured speciesdistinctive across the district. Itincludes some of SA’s primepotential tourist sites, especiallythe Greater St. Lucia WetlandsPark and the Tembe ElephantPark.
Most of the area is severelydeficient in basic infrastructure,yet there are a few quitesophisticated assets, including the
Jozini Dam and a military airbase.Some of the land is superb forlabour-intensive agriculture withgood potential profit-yields, suchas cotton and citrus, while otherareas will support only hardier andless lucrative production, such assugar-cane. Even the potentiallyhigh-value yield is poorly realisedat present, however, because ofsparse road access for transport-ing crops to market andbottlenecks in water supply forirrigation and household use.
Those activities that are presentlyproductive are frequently failing tocapture significant shares of theprofits they generate within thedistrict, shedding them instead tointerests from Durban that supplythe services necessary to make upfor inadequate ground infra-structure.
Here, then, is an area whereinfrastructure provision can clearlyconstitute genuine investment thatcould grow a self-sustaining andexpanding range of capital(including human capital) assets.As with all investment, however,the key is to figure out how tosequence it efficiently, so thatprecious resources spent on initialinputs can start self-amplifyingchain reactions.
I will provide a specific example ofthe sort of prioritisation-and-sequence issue that can only beaddressed if SA has an enhanced,home-grown OVA tool. Resourcesfor major road expansion could
22
Each site study will begin with stocktaking of potential capital-growth possibilities.
focus first either on the agricul-tural potential of the MakatiniFlats, or on enhancement ofaccess for tourists to the elephantpark and the existing coastalresorts. Both would constituteinvestments. But if one schemewould fuel growth in the other, butnot vice-versa, then perhaps wecan get two for the price of one ifwe can identify this and so get thesequence right.
Now let me illustrate thewealth-effect problem as it arisesin this instance. Expansion oftourist-utilised roads wouldautomatically be favoured bystandard CBA analysis because thecurrent capital value of the assetsrelevant to the tourists is so muchhigher than that of land andavailable labour potential whichcan garner only small profitmargins without both roadworkand irrigation provision. But weknow from experience elsewhere
in the world that touristsconcentrate best in areas wherethe existence of other economic
activity efficiently supportsprovision of ranges of services(as opposed to just servicescustomised for the touriststhemselves).
Wider travel market
Furthermore, recreationalattractiveness to less wealthySouth Africans might ultimatelybuild a tourist base that makes upfor its lower per-tourist incomeyield by being less sensitive tofluctuations and fads in the widertravel market.
At present, however, these canonly be conjectures, difficult todefend against arguments basedon more quantitative estimationssupported by traditional (straightCBA) analytic instruments. Thesituation demands an OVAmechanism customised to SA.Again, we stress that analysis ofthe sort we plan to make possible
will not necessarilyrecommend the Makatinidevelopment - and that isprecisely the point. Use of amodel, such as standardCBA, in which outcomes arepredetermined beforeapplication indicatesinappropriate - becausecompletely uninformative -selection principles.
Informative andsystematic
On the other side of thecoin, simply swamping a model’stendency to predeterminatenessthrough use of ad hoc plug-ons —for example, treating
23
Soweto streets....whatever their condition,they have to be used
maximisation of immediate jobs asa quantitatively arbitrary value initself — implies that systematicmodelling has, in effect, beenabandoned altogether, since theplug-ons must then be doing allthe analytical work. OVA aims tobe informative and systematic,though developed under theinfluence of local site conditions;and so the result of applying itcannot be predicted in advance.
Each site study will begin withstocktaking of potentialcapital-growth possibilities thatdepend, partially or wholly, onbasic infrastructure provision,including road-building orenhancement. At Makatini we finda range of non-transferable assetsthat are possibly under-utilised.We say ‘possibly’ here because itis precisely the point of our projectto enable us to measure apparentunder-utilisation and theopportunity-value of investment torelease trapped capital.
The agricultural anchor of theMakatini Flats is the Jozini Damand the canals that have beenlying idle for over three decades.Only some 4,000 ha out of apotential 15,000 ha on the Flats(the Pongola flood plain) havebeen utilised with limited success.The ‘railway valley’ on the inlandside of the Lubombo Mountains(around the town of Mkuse) couldrealise its yield potential only ifcanals and pumps were installedto lift water out of the dam intoanother catchment.
Some studies commissioned bythe KZN Department of Agriculturehave suggested that investorscould be induced to seek returnson ultimate possible yields from6,000 ha of gin cotton, 400 ha ofessential oils, and vegetables forsupply to the Gauteng market, ifexpansion and upgrading of theirrigation system wereforthcoming.
However, it seems likely that noneof this development would becapital-efficient without betterroad links from the Makatini Flatsto the coastal spine road, and anew spine along the coastal side ofthe Pongola River. Provision ofsuch links would draw the Flatsinto a transport web connectingthe West with Maputo andRichard’s Bay; at present, theLubombo Mountains and the passover Jozini stand in the way ofsuch a web. Elimination of thepresent transport obstacles would,perhaps, permit the efficient
interconnection of agriculture inthe Flats with timber and nutharvesting activities near thecoastal areas, and withmicro-farming to supply touristresorts to the North-East.
A road link along the Mkuse Riverthrough a gorge in the LubomboMountains towards the N2 wouldalso connect the Flats directly withthe military airport at Mkuse, andthus open another stable market.If the Flats can be drawn into asufficiently large market network,
24
The model must be worked up in stages, with constant feedbackthrough actual development applications as we go.
it is possible that extensiveaquacultural infrastructure(prawns) on the Flats themselves,along the Mkuse flood plain, andaround the St. Lucia lakes, couldbecome cost-effective.Here, then, is a possible weave ofdense externalities in infrastruc-ture development that makes asophisticated, South Africa-specific, OVA instrumentimperative. What is suggestedabove is, in its absence, purespeculation. The purpose of anOVA instrument is to provide ananalytical tool that will carry us toa rigorous andreliable test ofit.
Note that we arebeginning withrural areas aspilot sites. Thisis not becausewe don’t needan OVAinstrument foruse in urbanareas just asbadly. Rather, itis because themodel must beworked up instages, withconstantfeedbackthrough actual developmentapplications as we go. The webs ofpotential capital interconnectionsare much more complex in urbanenvironments than in rural ones,and we need to learn to walkbefore trying to run. The principlesthat will be learned on our initial,rural, pilot sites will cruciallyinform later extensions of the
research in Gauteng, around CapeTown, and elsewhere.Indeed, an essential source oflearning in our model developmentwill be cross-comparisons amongsttest sites. This explains our choiceof Oliver Tambo as the secondsite. Here we find the simplest,least complex, and most stark sortof development environmentpossible, where systematicrelations amongst a small set ofvariables can be most swiftlyexposed. Almost everyone inOliver Tambo is formallyunemployed. The overwhelmingly
greatest part of the capital assetpotential is lying fallow. Every newintervention can thus be expectedto have effects readily and reliablymeasurable against a relativelystatic baseline. Yet the plannedenhancement of the N2 connectingEast London and Durban mightproduce explosive multiplication ofexisting asset values if the right
25
Road improvements — an investment in associated assets
accompanying mix of otherinfrastructure provision can beidentified.
OVA for SA cannot be built frompure theory in an economist’soffice; the point of the exercise isto learn about what is special inSA’s conditions, and then capturethis knowledge in a systematic butresponsive instrument. These factslie on the ground, not in abstracttheory. It is from the ground thatwe must therefore collect them.Our goal is to develop a processwhereby measurement practicesand economic conditions aresystematically related to oneanother. Growing this process willrequire, in the first place, thattheoretical considerations of thesort discussed above guide initialmeasurements, but that thetheoretical basis be itself modifiedin light of sensitivity analyses ofthe data produced by the
measurements. This implies thatthe initial measurements must becarried out in direct workingpartnership between the peopleforging the model, and those whohave working experience ofdevelopment initiatives on thesites.The first phase of SIDAP work,just now completed, was thereforeaimed at establishing our role asdevelopment partners with bothSANRA and municipal planners.We must fit into existingprocesses, not seek to supplant orcompete with them. At the
moment, municipal authorities cangain access to development fundsby producing IntegratedDevelopment Plans (IDPs) whichidentify and justify priorities. It iswith respect to such activity thatlack of a micro-based, site-sensitive instrument like OVA mostobviously expresses itself.
Now, of course, we don’t haveOVA yet, but development of IDPscan’t wait and must go forward. Asstressed above, the process has tobe one of generate-and-test,which implies actually buildingthings on micro-scales from theoutset and gradually scaling upour initiatives as we learn. InAugust of 2002, we therefore senta two-man team, consisting of ayoung economist, LaurenceWilse-Samson, and an urbanplanner, Simon Plunk, into two ofuMkhanyakude’s regionalmunicipalities, Jozini and Big Five
False Bay, to add their technicalexpertise to the local knowledge ingenerating new and professionallyenhanced IDPs.
Along with this work, Wilse-Samson and Plunk compiled asurvey of all the existingdevelopment ideas, recognisedmajor capital assets, and currentlyidentifiable investment links, foruMkhanyakude as a whole. Thissurvey is about to be publishedand circulated by Sabita, as thefirst official SIDAP output. Itconstitutes the first instalment of
26
The principles that will be learned in our initial rural pilot sites willcrucially inform later research in urban areas.
the database that will be thelaunching pad for OVA develop-ment, and that will itself grow incomplementarity with it.
The new Jozini and Big Five FalseBay IDPs will be publishedimmediately afterwards as SIDAP’ssecond output. These will reflectand document our real role asdevelopment partners withSabita’s fellow stakeholders, andso prepare us institutionally forthe next, much more ambitious,phase of SIDAP. However, ouroutputs are not just things toread. Thanks to help inimplementation from SANRA, thenew IDPs will generate immediateconstruction of some new roadenhancement and roadsidefacilities, irrigation schemes,animal husbandry traininginitiatives, and other concreteassets.
With this exciting work behind us,we are now ready to launch theOVA development exercisedirectly. Working under mysupervision, an economics lecturerfrom the University of Cape Town,Mr. Samson Muradzikwa, willspend the next three yearsdesigning, as his Ph.D. thesis, afirst OVA tool based on theresearch at the pilot sites. Mr.Wilse-Samson will stay with theproject as a Master’s student,assisting Mr. Muradzikwa.
Their work will be fully funded bySabita, and facilitated throughoutby SANRA and our other partners.By the time their work is
completed, the production of newgenerations of increasinglysophisticated OVA tools, toultimately cover the entire nation,will have a self-sustainingmomentum of its own, and afully qualified career-lengthchampion in what will then beDr. Muradzikwa. We intend thatthis will in turn be the fuel thatfans national CGT reform.
A new way of lobbying
Sabita does not pretend to besomething other than what it is:i.e. an industry interest group.However, it is demonstrating byexample a new approach tolobbying that is especially suitablein the new South Africa. Instead oftreating resource allocation as azero-sum game, in which lobbyistsseek to enhance support for theirspecial interests by enticing itaway from the preferences ofothers, Sabita seeks to establishits credibility and sincerity as adevelopment partner withgovernments, agencies, otherbusiness sectors, and localcommunities.
SIDAP will directly benefit Sabita’smembers by encouraging moreefficient use of existing publicfunds, and faster creation of newrevenue bases, for roadwork. Butin the process SIDAP will benefitall South Africans by speeding upthe pace of development andhelping current generations toleave capital stocks as broad anddeep as possible for future ones tobuild on. �
27
While roads and streets,whether in good or badcondition, stare some of
us in the face all the time, few ofus make the connection, muchless understand, the full impact ofroads on our daily lives. This isparticularly true of thosecommunities living in neglected,underdeveloped and dis-advantaged townships.Certainly we all complain whenunpaved roads are dusty in thedry season, or muddy and pooledwith water when it rains; of coursewe curse when our cars bumpthrough potholes or taxis refuse todrop us closer to home; and yeswe grumble frequently about ourchildren’s safety when there areno sidewalks or streetlights.
But these are trite issues, focusedonly on our immediate andpersonal discomfort. It hastherefore been a privilege for meto be part of Sabita’s eye-openingtours to Soweto and the WesternCape townships, in which thebroader social and economic
implications of poor roads weregraphically demonstrated.
These site visits to urbantownships to assess the currentcondition of roads, and theadequacy of local governmentdelivery, should be seen as anadjunct to Sabita’s broader effortto develop tools and mechanismsto assist all levels of governmentin developing South Africa’s roadinfrastructure. This effort isencapsulated in the Ross Reportand the SANRAL-partnered projectin KwaZulu-Natal to develop anOpportunity Value Assessment(OVA) model for South Africa.
The site visit to Soweto took placein June 2002. During a bus tour
through the sprawling city thatwas conceived as a dormitorytownship, the 46-strongcontingent of Sabita officebearers, local councillors andofficials, and media represen-tatives, learned in no uncertainterms how poor roads contribute
28
The impact of poor urban roads
Township visits a wake-up call tolocalgovernment
Daniel Mashatola, Convenor,Sabita Advisory Group on
Development (AGOD)
Each site study will begin with stocktaking of potentialcapital-growth possibilities
to poverty, depression and socialand economic stagnation. Bycontrast, the community pride,confidence, high morale andongoing development whichcharacterised areas with goodroads was visually startling.
The broad objectives of the visitwere to:
• create an awareness of theimportance of roads and howthey contribute to socio-economic development;
• contextualise the applicabilityof the Ross Report to under-developed urban areas;
• demonstrate Sabita’scommitment to developing itsInfrastructure DevelopmentAssessment Project (SIDAP)(See Page 20);
• promote Sabita’s LocalGovernment EmpowermentProgramme to assist andeducate those officials taskedwith infrastructure delivery;
• provide those officials withsome technical background;and
• demonstrate how the AsphaltAcademy is working toensure that training andeducation in the blacktop
industry meets industryneeds.
A feature of these visits was thatthey opened the door foremployees of Sabita members toparticipate in, and make a veryreal contribution to, Sabita’sincreasingly important partnershiprole with all levels of government.
Sabita’s Advisory Group onDevelopment (AGOD), consistingof myself (Engen), Fani Xaba(Tosas), Vuka Nkosi (Black TopHoldings) and Richard Ntombela(Colas SA) made valuablepresentations to the attendingguests.
Presentation topics ranged fromthe detrimental and costlyconsequences of delayed orshelved maintenanceprogrammes, to the wide range oftechnical training materialavailable to councillors andmunicipal officials to assist in themanagement of road systems.
Significant contributions were alsomade, throughout the process, byMike Makweya of BP Africa andMike Muendane of Soul Talk.
29
Richard Ntombela Vuka Nkosi Fani Xaba
Dramatic feedback
Feedback from the guests wasdramatic! Councillors, many ofthem struggling with the problemsof budgeting and delivery, weresuddenly made aware both of theimportance of infrastructuredelivery, and that a supportsystem, of which they had neverbeen aware, existed and was ableto help. Council staff grapplingwith skills-depleted departmentslearned that technical trainingmaterial covering all aspects ofroad construction andmaintenance, including labourintensive construction, could easilybe obtained.
The lessons were invaluable!
Shortly after our visit to Kliptownin Soweto, where we saw arun-down informal settlement,polluted river banks and a motleycollection of small traders, JabuMoleketi, Finance and Economic
Affairs MEC for Gauteng,announced a R400-million faceliftfor Kliptown. Aside from upgradingroads and sidewalks, the projectincludes a revitalisation of thetraders’ market, construction ofthe Walter Sisulu monument and1200 housing units, and theprovision of 3000 serviced erven.This was very exciting news forus, and we could not have had abetter demonstration of thesuccess of the Sabita road-shows.
Our visit to Cape Town’s urbantownships - Khayelitsha, Philippi,Gugulethu, Langa and Brown’sFarm - followed the same patternas the Soweto visit, and again themore than 30 guests declared it agreat success, and for the samereasons outlined above.
From our point of view, the newsthat Danile Landingwe, CapeTown’s MEC in charge ofTransport, had initiated a projectdubbed “Vuka-Hamba” (Wake upand Go) to surface all gravel roadsin Gugulethu using local labour,was very heartening. This newscontrasted sharply with the almostsimultaneous announcement of aR200-million cut in the City ofCape Town’s road maintenancebudget — and is a graphic pointerto the impact the Sabita-sponsored roadshows are makingat grassroots level.
What was very exciting to me andto the other members of AGOD
was to share the stage with Prof.Ross, whose ideas are driving theentire machinery of Sabita’s lobbycampaign. Of particular relevancewas Richard Ntombela’s presen-tation outlining the detrimentaland very costly consequences ofcutbacks in road maintenance.His comments really hit home, andalso underlined the relevance ofProf. Ross’s concepts of “shadowline”, “hyperbolic discounting” and“infinitesimal margin”.
30
It is inconceivable ... that there are still sections of black townshipswhere road infrastructure is ... non-existent.
For many of us who only see CapeTown’s commercial areas on ourbusiness trips to that city, our tourof the townships was a fascinatingeye-opener, and a valuableeducational experience.It is inconceivable in the newdemocracy in which we live thatthere are still sections of blackurban areas where roadinfrastructure is absolutelynon-existent. Part of Philippi isjust such a sad story. Luckily,enough of the councillors who tookpart in the visit were equallyshocked, and promised to take thematter up with the relevantauthorities. This is further proof, ifany is needed, of the WAKE UPvalue of the Sabita roadshows,which derived much of theirimpact from the input of PietMyburgh and Kevin Kevany ofCorporate Image Holdings.
Comparing the Philippi area withthe luxuries of Clifton confirmsexactly why South Africa has oneof the highest GINI coefficients inthe world! (The GINI coefficient isthe standard measure of thewelfare gaps between differentpopulation groups within acountry).
Brown’s Farm presented anequally troubling sight. Althoughthe roads were surfaced, theyurgently need maintenance, and inone section the road was bisectedby a pool of water more than 10metres long. I shudder to think ofthe financial implications of thiskind of design fault in these times
of funding scarcity. The cost ofdoing things right the first timeversus the cost of having to re-dothings is something we should allbe very aware of.
The impact of the first two Sabitaroadshows to urban townships,both on immediate and onpotential service delivery, cannotyet be calculated. Perhaps in thenot too distant future theupgrading of Kliptown and theGugulethu roads will provide ourfirst concrete insight.
However, early indications are thata significant contribution hasalready been made towardspromoting an awareness of thedevelopment potential of goodroads, of the social and economicretardation occasioned by poorinfrastructure, and of theimportance of efficient delivery atlocal government level.
We cannot afford to lose thismomentum! Plans are already inthe pipeline to stage follow upvisits to townships in other SouthAfrican centres. On the basis ofwhat we have already achieved,there is very good reason to arguethat a continuation of the Sabitaroadshows will yield rich benefitsin the form of local governmentdelivery, with highly beneficialsocial and economic spin-offs forthe communities involved.
Ultimately, all of South Africastands to benefit! �
31
Engen Ad
32
Amidst tough economicconditions in 2002, the civilindustry continued on the
growth path it embarked on in2000. Spiralling inflation due toexogenous cost-push factors likethe depreciation of the Rand andincreased oil prices led to severalincreases in the repo rate.Though it was feared that the tightmonetary stance aimed at curbinginflation would turn off the taps ofdomestic economic growth, theeconomy showed its resilience,expanding in the region of 3%.Growth in real gross fixed capitalformation increased to 8.7 % inthe third quarter of 2002, from7.7 % in the second quarter and7.1% in the first quarter.Construction works increased by8.1% (real terms) in the thirdquarter of 2002.
Contributory reasons for thecontinued growth in the civilindustry include a decreasedbudget deficit leading to increasesin government’s capital expen-diture budgets, the delivery of theCoega deep water port project,and private sector spending,especially on the back of theplatinum boom. It became
apparent in 2002 that thegovernment had realised theimportance of developing andmaintaining economic and socialinfrastructure, increasing thecapital expenditure as apercentage of total governmentexpenditure to 15.8% of 2002/03budget. Though the institutionalincapacity to spend the allocatedfunds has plagued the differenttiers of government, a process isunderway to identify and eradicatethe bottlenecks.
The latest performance indicatorsfor the second quarter ending June2002 were used to gauge theindustry. These indicators providea good indication of how theindustry is doing and where it isheading. The following are ofimportance:
1. Confidence levels remainedoptimistic in the second quarter,and though the quarter on quarterchange in the levels weremarginally down, preliminaryresults show a further increase inconfidence in the third quarter.
Confidence leads the industry bynine months to a year. The grey
33
Roads and the civilindustry: 2002
Pierre BlaauwEconomist
SAFCEC
Institutional incapacity to spend the allocated funds has plaguedthe different tiers of government.
shades in Figure 1illustrate quarter onquarter growth in theindustry for threequarters or more. Asthe optimism amongstthe contractors equalslevels in ‘89 whenMossgas was built,prospects for growthin 2003 look good.
2. Tender activitypicked up in the firstsix months of 2002with a cumulativeincrease in the numberof tenders of 43%compared to 2001.
3. During the first six months of2002, the value of contract awardsdeclined marginally in real termscompared to the same period in2001. For the 12 months up to theend of June (2002) it rose by 8%.
4. Turnover increasedby 9.31% (real terms)in the first six monthsof 2002 compared tofirst semester 2001.This correlates withcontinuous positiveexpectationsregarding staff levelsfor the last fourquarters also gaugedamongst thecontracting membersof SAFCEC.
The following graph1,compiled using theSAFCEC contractaward database assample, shows the
importance of roads as part of thecivil industry. With a share ofbetween 40% and 60% of totalcontract awards during the pasttwo years, roads and bridgesclearly act as a crucial driverbehind the growth in the industry.Central Government is the most
34
0
25
50
75
100
200201
200101
2001
9901
9801
9701
9601
9501
9401
9301
9201
9101
9001
8901
8801
Index Trend
Civil Engineering Confidence Index
Figure 1. Civil engineering confidence index
Roads & Bridges Other **
1995 1996 1997 1998 1999 2000 2001 2002*
Civil Contract Awards Distribution
0%
20%
40%
60%
80%
100%
Figure 2. Distribution of contract awards* Up to the second quarter ** Other refers to the categories excluding
roads and bridges in Footnote1.
important client with the provincialand local tiers of governmentsecond and third respectively.This underlines the importance ofpublic expenditure,hence the optimismabout the prospects inthe coming years inthe light ofGovernment’s plannedexpenditure oninfrastructure,including roads, overthe medium termexpenditureframework.
This was echoed in theannouncement, madeby Minister of Transport DullahOmar in August 2002, thatR30-billion will be spent over thenext five years on maintenance,rehabilitation and the developmentof rural roads. Although thesefunds are still to be approved byCabinet, and the figure is believedto amount to about R1-billionRand spending per annum inaddition to what is alreadybudgeted, it clearly illustrates theintention to spend.
In addition to the plansfor rehabilitation anddevelopment ofprovincial and ruralroads, the unsolicited bidtoll road projects providemore reason foroptimism. Though itwould appear that thedelivery of these projectsis stunted, there is goodreason to believe that by2006 most of theseprojects will be in variousstages of development.
The graph above illustrates thedevelopment of toll road projectsrolled out according to a proposedschedule provided by the South
African Roads Agency Limited in2002. The proposed majorexpansions include the N1/N2,R300 in the Western Cape, WildCoast Road as well as the SuperHighways including the BenSchoeman road in Gauteng.Despite the fact that parlia-mentary pressure groupshave voiced their concernsregarding these developments, itis still one of the most viableapproaches to addressing the
35
100%
80%
60%
40%
20%
0%
Roads and Bridges Clients
2001 2002
CEN CORP LOC METRO PRIV PROV RSC WATER
Figure 3. Roads and bridges a crucial driver
Total Road Expansion (2001 = 100)
Years 2002 - 2035
Millions
0
500
1000
1500
2000
2500
3000
2 0 43 5 6 7 8 9 10 11 12 1413 15 16 17 18 19 20 21 22 2423 25 26 27 28 29 30 31 32 3433 35
Figure 4. Total road expansion
R6.5 billion backlog in themaintenance of national roads.
Growth for the civil industry in2002, based on the secondquarter results will be in theregion of 15% in real terms. Theindustry is expanding, recoveringfrom the 1999/2000 slump.Growth in 2003 would have beenrather flat however, were it not forthe fact that National PortsAuthority awarded contractsamounting to R2.2 billion for theNgqura deep-water port at Coega,stretching over three years. Inthe medium to longer term, thecivil industry is looking forward toa period of fluctuation around anupward trend. Large projectsapart from roads that will impacton growth include amongst othersthe rapid rail link between Pretoriaand Johannesburg, the Skuifraamdam and continued expansions inmining. Fluctuations will howeveralso be influenced by govern-ment’s ability to deliver, by
standarisation of procurementprocesses, and by the impact ofHIV/AIDS.
Not only in the domestic marketbut also in the broader Africansphere, initiatives like Nepad leadthe way towards accumulating thenecessary capital investmentneeded for development. Thiswill further provide goodopportunities for local contractorsto expand across South Africanborders in the coming years. �
36
1 The total civil industry include the followingcategories:
• Roads and Bridges
• Railways, Harbours and Airports
• Sewerage Schemes
• Water Schemes (e.g. dams)
• Township Services (includes the other
categories just on smaller scale)
• Miscellaneous (industrial type work including
mining e.g. aluminium smelter)
1. Background
As a result of the institutionalstructures prevalent in mostpublic authorities it is
common for the majority ofpersonnel to operate in so-called“silos” i.e. being responsible foronly one specific segment, or field,of whatever the deliverable maybe.
The creation of the South AfricanNational Roads Agency Limited(SANRAL) in 1998 as an organi-sation tasked with managing and
developing the national roadnetwork on “business principles”necessitated the implementationof a muchmore streamlined and efficientorganisational structure.
Being essentially a “management”organisation without anyspecialised line function capacity,the core function of all itstechnical personnel was seen asproject management i.e. manage-ment of, and responsibility for, aproject, from implementationthrough to completion. This
requires that all such personnelhave, or develop, generalknowledge and skills covering thebroad spectrum of engineeringdisciplines related to the provisionand maintenance of roadinfrastructure. Whilst this stillholds true in the present day, itwas soon acknowledged that thevaluable pool of specialised skillsand experience available withinthe Agency was not always beingeffectively utilised or transferredto lesser-experienced colleagues.
To address this situation the CEONazir Alli, instituted the formationof specialised “in house” clusters.
2. Specialised Clusters
In this specific context a clusterhas been defined as a core ofexperienced and skilled staff,together with junior colleagues,who have shown an interest in aspecific field. Following is a list ofthe various clusters that havebeen formed within the Agency:
• Design and Construction
37
SANRAL Clusters:Streamlining theorganisationalstructure Dennis Rossmann
Material/Pavement EngineerSANRAL - Eastern Region
The valuable pool of specialised skills and experience within theAgency was not always being effectively utilised.
• Environmental Management• Incident Management and
Road Safety• Materials and Pavement
Engineering• Routine Road Maintenance• Structures• Toll Operations• Traffic and Geometric Design
3. Materials andPavement EngineeringCluster
This cluster, currently consisting of13 members, is co-coordinated byBasie Nothnagel and is made up ofthe following components:
• Non-active mentors - Primaryfunction not currentlypavement and materialsrelated
• Active mentors - Primaryfunction is pavement andmaterials related.
• Core members
Professor Kim Jenkins, of theSANRAL Chair in PavementEngineering at the University ofStellenbosch, is also an activemember of this cluster, whichmeets on average twice a year tofocus on the following key areas:
3.1 Pavement Design
Current methods are evaluatedand new innovations, methods anddesign tools identified anddisseminated. The environmentalimpact of different pavementtypes is also evaluated.
3.2 Materials Design
The identification, evaluation andpromotion of new designmethodologies as well asinnovative products. This alsoincludes dissemination ofsuccesses as well as failuresexperienced.
3.3 Materials Testing
Relevance of current tests,amendments to existing testmethods, and the uniformspecification of tests.
3.4 Laboratory accreditation
The Agency is fully committed toraising the standard of materialstesting and is thus playing anactive role in the development ofappropriate accreditation systems.
3.5 Quality Control
The standardisation of site qualitycontrol requirements together withthe development of guidelines withrespect to the level of controlrequired for different types ofcontracts e.g. PPGS, BOT etc.
3.6 Standards/Procedures
Current manuals (internal as wellas external) are assessed withrespect to possible revision andupdating.
Standardised procedures for theprocurement of testing serviceproviders, laboratory/site audits,approval of mix designs etc. areformulated.
38
3.7 Specifications
Project specifications on testing,material properties, constructionmethods, functional requirements
etc. are evaluated andstandardised together with theidentification of “best practices”.
3.8 Pavement ManagementSystem
PMS survey methods,interpretation of outputs andprioritisation of projects.
3.9 Research
The identification anddissemination of new, (local aswell as international), researchdocuments as well as currentresearch needs. The link betweenresearch and practice, and vice
versa, is also promoted, togetherwith the development of a long-term pavement performance(LTPP) test section database.
3.10 Geotechnical
Development of a slope stabilitymanagement system, includingthe maintenance of a database on
all installed inclinometers, rockanchors etc.
3.11 Forums, Societies andAssociations
The identification of organisationswhere active participation bymembers of the cluster would beof benefit to the Agency.
3.12 Continued Education
Dissemination of informationresulting from individualattendance of courses, seminars,conferences etc.
4. Conclusion
Since the establishment of theseAgency clusters some two yearsago, tangible benefits with respectto in-house technology transferhas been experienced. In
addition, the increased uniformityin documentation requirements, aswell as decision-making, betweenthe various Agency regions is ofbenefit to all its various serviceproviders. Finally, the formation ofthese clusters has become anintegral part of the Agency’ssuccession plan. �
39
Tangible benefits with respect to in-house technology transfer havebeen experienced.
Tosas Ad
40
In response to a RoadPavements Forum (RPF)resolution, Sabita and C&CI
commissioned CSIR Transportekto investigate and report on roadfinancing at national, provincialand local government level.
The aim was primarily to be ableto evaluate the service delivery ofthe road authorities, against theirbudgets, and hence that of thecountry. It was foreseen that theinformation would cover allexpenditure, conditional grantsand transfers, as well asexpenditure in SADC.
Our previous article titledUnderstanding Road Budgetsand Expenditures in South Africa(Sabita Digest published 2002)gave an overview of the initiationof the abovementioned process.The article also served to highlightthe difficulties in gathering thebudget information required, andreported that, to date, theinformation so far obtained camemainly from the provincial andnational road authorities. Thisinformation was presented and
discussed at the Road Pavementorums held in Gauteng during2001 and 2002.
In order to understand the overallfunding allocation process better,the funding path for the differentgovernment spheres responsiblefor roads was illustrated. In Figure1 overleaf a map, compiled byTransportek, shows the SouthAfrican road funding flows. Itreveals the intricate compositionof the funding structure of a
specific road authority. It alsoexplains why long-termexecutional programming andbudgeting by road authorities isvital for sustainable servicedelivery. It is equally importantthat such authorities at least havea sound understanding of thebasics of pavement managementand service delivery so that theycan understand their ownbudgetary needs properly, andconvey this information to therelevant authorities.
41
Service delivery by roadauthorities:
Road budgetsand managerialskills
Wynand SteynManager
Infrastructure OperationsCSIR Transportek
Long-term executional programming and budgeting by roadauthorities is vital for sustainable service delivery.
Eduard KleynConsultant to
CSIR Transportek
Essentially all income to be spenton roads (provincial and national)in South Africa is funnelledthrough the National Treasury,from where allocations are madeto SANRAL (national roads), theprovincial legislators (for distribu-tion to all departments, includingprovincial roads) and various othernational departments fordistribution to local authorities.
Funding that bypasses this systemis toll income on national (notPublic Private Partnership) tollroads which goes directly toSANRAL, and own source fundingof provinces such as vehiclelicence fees.
The budgetary survey shows thatprovincial funding levels have ingeneral been increasing since1999. In some cases this increase
has been substantial, while inothers it was only marginal.However, the funding levels stilldo not seem to bear muchresemblance to the backlog andneeds reported by the authorities.Hence, the condition reports fromthe different road authorities, byand large, still indicate a generaldeterioration in network servicelevels.
While this situation certainlywarrants concern, discussions withthe responsible personnel from thedifferent road authorities (in aneffort to better understand thereasons for the situation) give riseto further concern. It is becomingclear that very few of the author-ities have enough experiencedpersonnel in charge of planningand programming for substantiveaction to be taken. Many
42
Figure 1. Mapping of current road funding flows1
RoadRevenues
MAPPING OF CURRENT ROAD FUNDING FLOWS GENERALTAXES
DirectAllocations
Provincial
Roads
National
Roads
Local
Roads
Other
taxes
Other roads
Parks BoardsEg Northern Prov.
Road AgencyVAT
Customs and
Excise Duties
Company Tax
Income Tax
Local Rates
Roads and
Transport
& Provision
Provinces NDoT DPLG DPW Las
SANRALMetros
(JRA)
NATIONAL
REVENUE
ACCOUNT
(Treasury)
License Fees
Fuel Tax
Tolls
DPW: Department of Works;JRA: Johannesburg Road Agency;Las: Local Authorities;
NDOT: National Dept of Transport.DPLG: Department of Provincial and
Local Government;
authorities have lost their skilledhuman resources and have, asyet, not been able to replacethem.
In many cases, maintenanceactions were observably out ofphase with the performance of theroad, and hence the immediatemaintenance need. For instance,actions applicable to preventivemeasures were being appliedwhen deterioration had progressedbeyond even routine maintenanceneeds into the special mainten-ance category. In other words,what funding is available is notalways applied cost-efficiently.Hence, the survey revealed anaspect of the “roads dilemma” thatwas not quite anticipated to thelevel encountered. While it is true
that much more funding isnecessary, if only to restorenetwork service levels to afunctional and sustainable level, itwill most probably be to little availif the shortage of skilled manage-ment and technical support withinthe road authorities is not simul-taneously addressed effectively.
This situation, once more, explainsthe difficulty experienced inobtaining the managerialinformation from some of theauthorities over the two years thatthe survey was conducted — theanomaly lies a few steps back ofthe immediate lack of deliverymanifestation.
In the light of the abovementioneddifficulties and disclosures inobtaining the managerial infor-mation, it is paramount that adedicated and appropriatelystructured training campaign bedeployed — and it should be anon-going process. It is not amatter of the technology andmethodology not being availablelocally — the technical insight andunderstanding of South Africanroad engineers and technicianshas been internationally acknow-ledged over the past years.
It is a matter of properlyempowering the country’s present,relatively young, governmentalmanagement contingent byensuring that each authorityemploys a sufficient number of
well-trained road engineers andtechnical staff.
This is vital, even if roadauthorities are forced to buy-inexpertise from private enterprisefor long-term assistance, becauselocal governments must at leasthave sufficient understanding andin-house skill to manage theirconsultants as well as to run thedepartment service cost-efficiently.
With adequate skills to manageadequate budgets the condition ofthe country’s road network can beimproved to provide the requiredservice levels to all road users. �
43
Condition reports from the different road authorities... stillindicate a general deterioration in network service levels.
Much Asphalt has extendedit’s social responsibilityprogramme to include their
Quad Squad project. This is in linewith its business plan objectivesand commitment to making acontribution toward the upliftmentof the communities in and aroundthe company’s asphalt mixingplant operations.
With the assistance of com-munications and advertisingagency, Mad Dot, Much hascompleted the first of the QuadSquad projects at Lwandle PrimarySchool in Khayelitsha. Theprojects have been launched inpartnership with two key accountcustomers, Power ConstructionRoads, and Zebra BituminousSurfacing.
A need was identified by the taskteam, who acknowledged that theharshness of the wet Cape wintersmade the act of meeting for dailyassembly at schools in previouslydisadvantaged areas a reallyunpleasant daily activity, particu-larly in those schools which hadless than the basic infrastructure.The idea of providing a suitablegathering place for learners andeducators was conceived.
With the assistance of the ANCYouth League, the concept wasdeveloped and a strategic plan
formulated. Contact was madewith the local MEC for Education,Minister Advocate André Gaum,who approved the concept withouthesitation.
Lwandle Primary School wasidentified as a prime candidate forthe pilot project, and work startedin December 2002 on theconstruction of a quadrangle ofapproximately 500 square meters.Much supplied the hot mix asphaltto a Power Construction Roads’paving operation close to theschool, and recovered asphaltfrom nearby rehabilitation workwas donated to the project by theCity Of Cape Town for the baselayers.
Preparation work such as levelingand compaction of the foundationlayers started in December 2002,as soon as the schools closed forthe holidays. The final applicationof the asphalt layer took place justbefore school reopened in midJanuary 2003. The learners thusreturned to a brand newquadrangle, proudly completed bythe Quad Squad.
A grand opening ceremony washeld on 21 February 2003, and theceremony was attended by severalsenior provincial and local govern-ment dignitaries.
44
Social responsibility programme:
Much Asphalt kicks offits Quad Squad initiative
John OnraëtDirector
Much Asphalt
The development of anappropriate and suitable selectionprocess is currently underway, anda further six West Cape schoolsare to receive Quad Squadattention in the 2003 calendaryear.
Funding strategies are currentlyunder review, and these will
include the recruitment of largecorporate companies to “Adopt aQuad”. Much Asphalt will continueto champion the project.
Much Asphalt has commercialasphalt production facilities in allmajor centres, and the intention isto carry out Quad Squad activitieson a national level. �
45
Note for JON: John Onraet has promised a pic from today’s opening
46
47
2HumanCapital
Development
Introduction
Starting on familiar ground,we all know only too well theconcept of the life cycle of
roads. In fact, the concept of lifecycle engineering is daily breadand butter to most of us, andderives from the development ofinfrastructure managementsystems pioneered by people likeHudson and Haas with their workon pavement managementsystems (PMSs).
This small beginning in the early1970’s has led to the developmentof other systems to manage,maintain and even rehabilitatevarious other civil engineering
infrastructure facilities. Thisincludes buildings, airports,bridges, storm-water systems,road furniture and even footwaysand verges. There has also been ageneral awareness of the life cycleof engineering projects, with moreengineering activity in themanagement, rehabilitation andclosure of facilities versus thepre-1970’s focus on the planning,design and construction offacilities.
However, it is interesting thatalthough planning, design andconstruction make up only about 5to 10% of the total life cycle ofengineering facilities, the rest ofthe life cycle (90 to 95%) mostlydeals with the maintenance,rehabilitation and closure. Thereverse of this trend happens inthe training and education ofengineers. In general theeducation and training ofengineers all over the world, atundergraduate level, tends tofocus virtually 100% on thedesign, planning and constructionaspects of projects. It is acceptedthat the undergraduate
programmes are very compactand full. It is accepted thatknowledge of maintenance,management and rehabilitation isa specialist area which needs to beaddressed at the postgraduatelevel.
The reality is that even atpostgraduate level courses tend tofocus on the same small portion ofplanning, design and construction
48
ARE WE LEARNING?
Aspects of life-cyclelearning
Emile HorakHead, Department of Civil and
Biosystems Engineering,University of Pretoria
Life-long learning has to take place for any person to makeprogress in his or her career.
of the life cycle of engineeringfacilities. This is the mainmotivation for the recentdevelopment of a newpostgraduate masters degreeprogramme on Fixed AssetMaintenance and Management(FAMM) at the University ofPretoria (Horak, IMIESAConference 2002).
The investigation leading up to thedevelopment of the new FAMMmasters programme also drewstrong parallels between theissues faced in life cycleengineering in general, and that oflife long learning. As in the caseof life cycle engineering, the newengineer-in-training goes intohis/her professional life with verylittle life long learning skillsacquired to promote survival andsuccess in his/her professionalcareer.
In SA the new Skills DevelopmentAct is formalising this aspect,while in the European Union greateffort is currently being invested inharmonising and virtuallyinstitutionalising life long learning.The South African Institution ofCivil Engineers (SAICE) is alsoattempting to institute aContinuous Professional Education(CPE) system similar to thattouted by the medical profession.The fact that the aspect of life longlearning skills is being measuredas an outcome in the accreditationprogramme of the EngineeringCouncil of South Africa (ECSA) isfurther proof of the recognition ofthis need.
However, the complex process of
learning means that theacquisition of life long learningskills is not something which canbe achieved in a mechanisticfashion. How this skill is acquiredis still shrouded in vagueness. It isoften assumed or implied to besomething which will happenautomatically. Add to this thatmost of us have a naturalresistance to learning and thepicture becomes even morecomplex!
In this paper an attempt is madeto put together some pieces of thelife long learning puzzle based onconceptual models of careerdevelopment, aspects of learning,and creativity. Hopefully it can actas a road map to point the way forthe development of the skill of lifelong learning that is needed tomaintain and develop our owncareers.
It may also act as a mirror intowhich we can look and perhapsask the question: “Mirror, mirroron the wall, who is still learning ofus all?”
The Career Model
Edgar Schein, from the SloanSchool of Management, MIT,produced a paper in the 1970sentitled: “Personal Growth andCareer Development: Theindividual, the organisation andthe career: A conceptual scheme”.This study was based on researchon individuals and largecorporations, and has become abenchmark in human resourcestudies and practice.Schein developed a conceptual
49
model which is very useful fordemonstrating what happens to aperson’s career in an organisationor in the work environment ingeneral. During his/her careerevery practitioner has to cross anumber of barriers or hurdles inorder to progress with that career,and this process demands twomain skills — Socialisation andInnovation.
Figure 1 clearly illustrates that thesuccess of a person in theworkplace depends on his/herability to learn and exercise
organisational socialisation skillsas well as innovation skills.As can be seen, we enter anorganisation with hopefully arather high level of socialisationskills. Socialisation generallyrelates to the values, attitudesand culture of an organisation.
This definition of socialisation isalso strongly linked to educationand training. Upon crossing eachbarrier there is an increased needfor such socialisation skills,whereafter the need drops againuntil approaching the next barrier.The need for learning is thereforecontinuous throughout ourcareers. Let us take a look at whatthis really involves.
Go with the flow
Schein’s career developmentmodel clearly illustrates that life
long learning has to take place forany person to make progress inhis/her career. Educationalists tellus that we must get into the“flow” of learning! This “flow”theory of life long learning isdescribed by Reiber (1996) asfollows:
50
Figure 1. Career stages (Schein, 1976)
Innovation
Socialisation
High
Low
RELATIVESCALE
Pre-entry Entry Initiation Promotion TenureBasic First Second
Training Assignment Assignment
“Flow theory gets its name fromthe way so many adults havedescribed a peculiar state ofextreme happiness andsatisfaction. They are so engagedand absorbed by certain activitiesthat they seem to ”flow" alongwith it in a spontaneous andalmost automatic manner - being“carried by the flow” of theactivity."
Dr Mihaly Csikszentmihalyi (1990)is an educationalist who modelledthis “flow” theory of life longlearning. Educationalists like himbase this on Piaget’s theory whichboils down to the fact that nolearning can take place unless anindividual is challenged or in astate of disequilibrium. To get intothe “flow” and experience theassociated enjoyment, a personhas to strike a balance betweenanxiety and boredom!
In Figure 2 Csikszentmihalyi’smodel of the effects of skill and
challenge on enjoyment areillustrated conceptually.Enjoyment comes at the specificmoment when the person’s skillsmatch the challenges of the
activity. These educationalistspoint out that this enjoymentperiod is dynamic, since oneperson may experience boredomwhile another less skilled personmay experience anxiety. Duringthis enjoyment period, “flow”takes place. This dynamic processalso ties in with the fluctuation ofsocialisation skill levels, explainedby Schein in his model as varyingchallenges occur during thevarious stages of a career.
The problem is also thatknowledge can decay! In a senseknowledge acquired is like fruit. Ifyou don’t eat it and use it whileripe, it decays and wastes away. Itis literally like that frustratingrugby rule, “use it or lose it!”Educationalists tell us that the“half life” of knowledge acquired isoften less than the length of thestudy period. Personal experiencewith students tends to imply thatthis “knowledge half life”sometimes seems to be less than
one semester! This isfurther proof that learningmust be sustained inorder to ensure usefulknowledge and skills -which means that weliterally need to fluctuatebetween challenge andboredom, and shouldexperience changeperiodically.
The impact of change dueto the challenges we facecan also be described in
terms of various stages that we gothrough in the learning process. InTable 1 this is described in termsof feelings, thoughts andbehaviour. We all can associate
51
Enjoyment
Boredom
Anxiety
SKILLS
CHALLENGE
High
Low
Low High
Figure 2: Csikszentmihalyi’s learning model
and recognise these stages, sincewe must all have experiencedthem at some stages of ourcareers. Some readers may find itof interest to place themselves inthe context of these stages. Theprocess may help some of yougain an understanding of what is
currently happening to you.Csikszentmihalyi concludes thatthe flow of learning can only takeplace if one or more of thefollowing situations arise:
• The challenge is optimised;• Attention is completely
absorbed in the activity;• The activity has clear goals;• The activity provides clear
and consistent feedback as towhether one is reaching thegoals;
• The activity is so absorbingthat it frees the individual, atleast for the moment, fromother worries andfrustrations;
• The individual feelscompletely in control of theactivity;
• All feelings of self-consciousness disappear; and
• Time is transformed duringthe activity (eg. hours passwithout being noticed).
We can again test ourselvesagainst this “benchmark” to seewhether we are currentlyexperiencing “flow” or for that
matter, have ever experienced it!If not, it is suggested that youstart by looking at some newchallenges.
Innovation
The other important career skill,according to Schein, is the abilityto innovate. This skill can also berelated to the individual’s ability tohave influence on the organisa-tion. Schein’s conceptual model inFigure 1 clearly shows thatinnovation and influence onlybegin picking up after the “tenure”or the established phase isreached. This innovation skilldevelopment or the need for itonly occurs rather late in thecareer.
Innovation can also be associatedwith research or the acquisition of
52
Stage Feelings of: Thoughts are: Behaviour is:
Loss Fear Cautious Paralysed
Doubt Resentment Sceptical Resistant
Discomfort Anxiety Confused Unproductive
Discovery Anticipation Creative Energised
Understanding Confidence Pragmatic Productive
Integration Satisfaction Focused Generous
Table 1. The impact of change (Adaptation from Brock and Salerno, 1993
new useful knowledge. Using thisas an indicator, recent researchdone by the Centre for Inter-disciplinary Studies at theUniversity of Stellenbosch can beused to illustrate the point. Thisstudy found that the ability to doresearch or to be involved in ittends to be concentrated aroundthe middle and end stages ofcareers in SA. In Figure 3 theresults of age distribution versus
research activity clearly showsthat the median of the averageage of researchers in SA was inthe age group 40 to 49 years in1990.
However, this median of theaverage age of researchers hassignificantly changed to the agegroup 50 to 59 years in 2000. The
SA researchers have thereforeremained in place, while aging asa group due to limited newentrants into the research arena.It also appears as if research in SAis increasingly being done by“pensioners”! Whatever ouropinions, this is confirmation thatinnovation and creativity, in termsof research, are only being used orrequired towards the end ofcareers, even in SA!
The creativity link
Innovation and creativity go handin hand. Strictly speakinginnovation is defined as thedevelopment of an invention whichhas proven itself in the market. Inorder to innovate or invent, weneed to be creative. Lumsdaineand Lumsdaine in their handbook
53
Research in South Africa is increasingly being done by “pensioners”
Researcher age distribution(Centre for Interdisciplinary Studies, US)
Age
%
0
20
25
30
35
40
45
15
10
5
>6050 to 59
40 to 4930 to 39
<30
1990
2000
Figure 3. Age distribution of researchers in South Africa
“Creative Problem Solving:Thinking skills for a changingworld” (1995) define creativity as“... playing with imagination andpossibilities, leading to new andmeaningful connections andoutcomes while interacting withideas, people, and theenvironment”.
Creativity needs to be nurtured asit has a limited shelf-life. In timewe also develop a number of
barriers towards creativity in life.Lumsdaine and Lumsdaine showthat natural creativity can also bestrongly age related if notnurtured. Figure 4 shows thatnatural creativity is at its highestamongst children or toddlers, andthereafter rapidly diminishes withage if it is not nurtured anddeveloped.
There are various reasons for thisdecline of creativity with age, intowhich we will not go at present.We observed from Schein’s modelin Figure 1 that innovation skills,and therefore creativity, areneeded towards the end of
careers, yet the trend of creativeability shown in Figure 3 runscontrary to that. If we have notnurtured and developed ourcreative ability, we may not haveit available when we need ittowards the end of our careers!
The good news is that creativitycan be nurtured and creativeability can in fact be independentof age! We must howeverovercome the barriers or blocks to
creativity in order to nurture it.Lumsdaine and Lumsdaine (1995)identified a number of mentalblocks which need to be addressedto free our creative and learningability. They list the followingseven blocks or barriers tocreative thinking and learning:
• False assumptions;• “There is only one right
answer”;• Looking at a problem
in isolation;• “Following the rules”;• Negative thinking;• Risk-avoidance or
fear of failure; and• Discomfort with
ambiguity.
Most of these obstaclesare self-explanatory,and will not bediscussed here in anydetail. It may be aneducational treat for
some us to read more about thistopic in any case. Some of thesestumbling blocks can be examinedby means of specific examples orillustrations, which will help clarifythe issues. For example take the
54
Creati
vit
y%
Age
(years)5 17 25 30
2
10
50
90
40
Figure 4. Creativity versus age
mental block of false assumptions.
According to Edward de Bono oneof the false assumptions we oftenmake is that highly intelligentpeople areautomatically good or creativethinkers. This is often referred toas the “Intelligence Trap”. Thereare various examples of“intelligence traps” in
organisations. We have all eitherseen such examples in life (wetend to identify our boss first!) orpossibly already havedemonstrated it ourselves.Another false assumption is that“play is frivolous”! Some of the
most innovative solutions havecome from a playful attitude.Humour is seen as an attituderelated to playfulness and is verybeneficial to creative thinking as itrelieves stress, tension, andmonotony - while also oftenswitching the mind to unexpectedtracks. “What-if” questions are notmerely daydreaming excuses, butare questions asked too seldom increativity exercises.
We engineers tend to be analyticaland hard-facts based, and oftenfind humour difficult to implementor understand. The result is thatwe hardly ever laugh at ourselvesor show enjoyment in our work.No wonder the youth look at ourprofession and often equate it withthe grey and drab world of beancounters.
Another angle to the “IntelligenceTrap” is lifted out by Chris Argyrisin Harvard Business Review(1991) in his article “TeachingSmart People How to Learn”. Itopens with the statement “Everycompany faces a learningdilemma: the smartest people findit the hardest to learn”. He goesfurther to state “....thosemembers of the organisation thatmany assume to be the best atlearning are, in fact not very goodat it. I am talking about thewell-educated, high-powered,high-commitment professionalswho occupy key leadershippositions in the moderncorporation.” This illustration
clearly relates mostly to themental block of risk avoidance orfear of failure. Argyris puts it verysuccinctly:
“Put simply, because manyprofessionals are almost alwayssuccessful at what they do, theyrarely experience failure. Andbecause they have rarely failed,have never learned from failure....they become defensive, screenout criticism, and put the ”blame"on anyone and everyone butthemselves." The latter clearlyrelates to the mental blocks ofnegative thinking and problemswith ambiguity since these peopletend to"...define learning toonarrowly as merely ‘problemsolving’, so they focus onidentifying and correcting errors inthe external environment."
55
“What-if” questions are not merely daydreaming excuses, but arequestions asked too seldom in creativity exercises.
Reflection in the mirror
Two things can happen now thatwe have seen ourselves in themirror image of life long learningskills. We may not enjoy what wesee, and may experience stress.The good news is that this isprecisely what is needed, since thefirst step in going through thelearning process is to experienceanxiety - a vital prerequisitebefore the change process cantake place! We need to bechallenged to acquire new skillsand knowledge and to go with the“flow” of the learning process.
The second possibility is that welike what we see and confirm that“if it isn’t broke, why fix it?” Youmay be the person sitting pretty inyour comfort zone bound forboredom and also in need of achallenge. Perhaps now is the timeto set some new goals and startdoing something about it. It mayinvolve formal learning courses oreven refresher courses. It may beself-study in an area likecreativity! It may even involvemaking some career changes.
According to Schein, by changingfunction or even discipline in anorganisation, the challenges
increase as more new boundarieshave to be crossed. By movingfrom one organisation to anotherthe number of boundaries to crossincreases even further, andrequires the change associatedwith a strong learning experience.Schein was one of the first topropagate the notion that careerdevelopment and personalfulfilment do not come frommerely trying to move verticallyup in the hierarchy of anorganisation as we may have beenprogrammed to think. The spaceat the top is limited in most cases.It may be better to considermaking moves horizontally overfunctional, discipline or evenorganisational boundaries.
If you are now inspired to makesuch suggested career moves,please do not leave the profession!We are already low on qualifiedpeople. We rather need to drawpeople into our profession with theexamples of people living excitingand challenging lives.
A final word of caution is that ifyou think this is a final andexhaustive review of life longlearning you are in serious need oflearning! �
56
Shell Ad
57
Introduction
It usually takes several yearsbefore medium term strategiescan be developed,
implemented, measured, adjustedand optimised — the fundamentallaws of time cannot be short-circuited without Orwelliantechnology! This basic principle isequally applicable to the strategyof the SANRAL Chair in PavementEngineering, and after our twoyears of existence the time is nowperhaps ripe for the SANRALChair’s activities and outputs to bemeasured against the aims of the5 year plan.
Advanced Courses
The main thrust of the SANRALChair is apparent from theobjectives of SANRAL itself,namely “development of humancapital and capacity building ... inthe field of pavementengineering”. As approached in2001, these objectives arepredominantly to be realisedthrough higher education andtraining activities, althoughresearch projects driven
specifically by the roads industryalso play a significant role.
Immersion courses that are shortand intensive, are presented overblock periods of a week at theUniversity of Stellenbosch as partof the main thrust in post-graduate capacity building andcontinuing education.
This has been identified as themost accessible and effective wayof engaging students andpractitioners in the roads industryalike. Such courses are aimed at
immersing delegates in thesubject matter that comprisesboth practical and theoreticalcomponents, using a combinationof lectures, workshops, tutorialsand practical sessions, whichprovides an excellent opportunityfor dissemination of knowledgefrom local and internationalexperts in the field of pavementengineering. Although the coursescarry credits that are transferableto other universities, delegates donot necessarily require a degreeas an entry criterion.
58
The SANRAL Chair in PavementEngineering
Overview of activitiesduring 2002
Kim JenkinsHead, SANRAL Chair inPavement Engineering
University of Stellenbosch
Cooperation with AsAc and Sabita will be extended
The scope of postgraduate coursesoffered was extended andformalised in 2002 to includeenough specialist courses inpavement engineering to supporta masters degree in this studyfield. A total of 7 courses is nowscheduled on a 3 year cycle ofpresentation, including PavementMaterials I (Granular andCemented), Pavement Materials II(Asphalt), Flexible Pavement
Design, Rigid Pavement Design,Pavement Evaluation andRehabilitation (Flexible), PavementConstruction and PavementManagement.Three block courses were offeredby the Chair in 2002, as shown inTable 1. Besides the mainpresenters, a greater proportion oflocal specialists was included inthe block courses to provide adeeper scope, and also to enhancethe practical component of thesubject material. Prof MarkAlexander, Dr Fenella Long, BryanPerrie, Pieter Strauss, Kobus
van der Walt, Gerrie van Zyl,Dennis Rossmann, Dave Collingsand Steph Bredenhann allprovided expert input on thecourses, in their specialist fields.
Pavement Materials II(Asphalt) Course
Professor Martin van de Ven ofDelft University of Technology andKOAC, the incumbent of the
former Sabita Chair, was invitedback to US, along with Dr LouisFrancken of the Belgian RoadResearch Centre (BRRC), toparticipate in presenting aweek-long course on asphalttechnology.This was an opportune time toengage these two asphalt experts,for a number of reasons. Prof vande Ven had been back in theNetherlands for a year, providingample opportunity for him toidentify appropriate technology inEurope for South Africa. DrFrancken, on the other hand, had
59
Course Duration Delegates(reg.
students)
SADCDelegates
Main Presenters
PavementMaterials II(Asphalt)
5 days 21(11)
3 Dr L. Francken andProf. M. vd Ven(International
experts)
RigidPavement
Design
5 days 32(12)
7 Prof. D. Zollinger(International
expert)
PavementEvaluation
andRehabilitation
5 days 30(12)
3 Prof. A. Molenaar(International
expert)
Table 1. Block courses offered by the SANRAL Chair in 2002
been involved in updating PRADO(a software package for modellingasphalt composition andbehaviour) and could provideinsights into BRRC’s latestdevelopments in this area justprior to his retirement.
The course covered many subjectareas but focused on binderrheology and modelling of binderbehaviour, PMBs, materialcharacteristics and specifications,asphalt mix design philosophies(including SA HMA Design Manualapproach), spatial composition,gyratory studies in Europe, fatigueand permanent deformation,
fracture mechanics, reflectivecracking, prediction of mixproperties from composition andvery thin layer asphalt.
Scheduling of the course inasphalt technology near thebeginning of the year was theprobable cause of the modestnumber of delegates. Thesubsequent courses attracted 30or more attendants, and this isillustrative of the growing interestof industry in continuingeducation. In particular, roadauthorities and consultants seemto be aware of the need forcontinual advancement of theirstaff’s skills levels. The number ofpostgraduate students attendingthe block courses for degreepurposes doubled in 2002, whichis a positive sign for the roadsindustry.
Rigid Pavement Design Course
A specialist course was offered inrigid pavement design in 2002with the primary input byProfessor Dan Zollinger of TexasA&M University. This course hadnot been offered previously at theUniversity of Stellenbosch.
Although it was not aimed at beingan advanced course, the combinedlack of work in rigid pavementdesign and the recent develop-ments in the technology in theUSA resulted in our exposure to avery challenging and exciting levelof technology.
The course content includedfoundation and subgradecharacterisation, stabilised layers,concrete mix design, durability,
types of concrete pavements andconstruction issues, failuremechanisms, pavement design,and rehabilitation. A designproject was included in theevening tutorials to allow variousdesign procedures to be tested.
Pavement Evaluation andRehabilitation
A formal memorandum ofagreement was signed in 2002 forcooperation between DelftUniversity of Technology and theUniversity of Stellenbosch, both atRector and departmental level.This will result in Prof. AndréMolenaar being engaged in US
60
There are signs of a growing interest in continuing education
activities more than ever. Hisinvolvement in postgraduatecourses and student exchange wasonce again evident in 2002.
Professor Molenaar assisted in thepresentation of the course onpavement evaluation andrehabilitation. The content of thiscourse included a recap of thefundamental principles ofpavement design and perform-ance, material characteristics andstresses and strains. In addition,statistics and probabilistic aspects,pavement evaluation, rehabili-tation design and non-standardmaterials were covered.
As with the other block courses,the attendance figures wereexceptional. Prof. Molenaar hasnow taught well in excess of 255students on these postgraduatecourses since 1995. In addition, itwas pleasing to have theattendance of delegates fromTanzania, Zambia and Lesotho.Since the transformation thatbegan in the early 1990’s, SouthAfrica has become the focal pointof technological transfer for otherAfrican states, particularly theSADC countries.
Undergraduate activities
Undergraduate studies provide thefeeder group for pavementengineers. Learners with thepotential to become pavementengineers need to be identifiedthrough carefully strategised andproperly structured events.Involvement by the Chair inWinter School activities (oneweek engineering orientation ofscholars in the July holidays) as
well as undergraduate coursessuch as TransportationEngineering 414 and DetailedDesign 446, provides excellentopportunities for profiling careeropportunities in pavementengineering.
Cooperation & Partnerships
Following on from the partnershipbuilding that was initiated in 2001,the SANRAL Chair continued tointeract with recognisedinternational institutions in 2002.
Two Dutch exchange studentsfrom TU Delft carried out researchat the University of Stellenbosch(US) in 2002. One masters degreestudent completed his thesisresearch in South Africa afterinitial involvement in HVS testingwith the CSIR. This studentfollowed up with laboratoryresearch on foamed bitumenmixes at the US. cooperationbetween the Chair, TU Delft,Gautrans and the CSIR affordedthis opportunity.The second masters degreestudent completed his “stage” orpractical phase at the University ofStellenbosch.
Cooperation between the SANRALChair and TU Delft also resulted intwo doctoral students from UScarrying out research in Delft.Both students benefited from the3-dimensional finite elementprogramme developed at TU Delftfor modelling pavement materials.The programme called CAPA 3Dwas used to model surface sealbehaviour and mechanical testingof asphalt with non-linearvisco-elastic behaviour.
61
Two major role-players in theasphalt industry in SouthernAfrica, Sabita and the AsphaltAcademy (AsAc), continued toenjoy cooperation with theSANRAL Chair in 2002. The “SkillsDevelopment Task Group” and“Accelerated Pavement TestingSteering Committee” of the RoadPavements Forum, as well as the“Foamed Bitumen Task Group”,provided scope for cooperation.
This cooperation involved theChair in the formulation of AsAc’sInterim Technical Guideline: Thedesign and use of foamed bitumentreated materials (TG2)and the dissemination of thisinformation through a series ofnational workshops.
In addition, the CAPSA SteeringCommittee activities got into fullswing in 2002, and the SANRALChair provided input as the Chairof the Technical Committee.
Research
Research effort of the SANRALChair is focused foremost onstudent development. However,scope exists for mutual benefitwhere the needs of industry andthe objectives of SANRAL can bemet through postgraduateresearch. Student orientatedresearch has included, amongstothers, the following subjects in2002:
• Investigation of theperformance properties of
emulsion treated mixes thatincorporate new types ofemulsifiers;
• Pre-coating of aggregateusing emulsions rather thantar based products;
• Development of aprobabilistic asphalt mixdesign model based onaggregate packing;
• High quality emulsion treatedblocks for road construction;
• Factors influencing asphaltcompactibility and theimplications of these mixcharacteristics on permanentdeformation of the mix.
Research for industry and SANRALin 2002 was carried out at theInstitute for Transport Technology
(ITT) at the US, where the Chair isrunning the laboratory pavementresearch. The following is asample of research completed in2002:
• Investigation of the ruttingand fatigue characteristics offour mixes for Texas CTR;
• Testing of a foamant forenhancing foamed bitumenproperties;
• Laboratory research(including triaxial testing) offoamed bitumen andemulsion mixes with cement,for cold mix recycling on theN7 near Cape Town; and
• Accelerated pavement testingof polymer modified asphaltmixes requiring rut resistantproperties.
62
A memorandum of agreement has formalised cooperation betweenDelft University and the University of Stellenbosch
Educational Activities
International seminars andconferences provide anopportunity for SA’s pavementindustry to be profiled. The Chairwas invited to present twointernational seminars in the fieldof Cold in Place Recycling in 2002,one at the University of Oporto inPortugal, and the other inWindhagen, Germany.
Several papers were presented atnational and internationalconferences, including AAPT inColorado Springs, and ICAP inCopenhagen.The Chair continued to serve asActing National Moderator for theATC courses. These courses arecurrently under review by theAsphalt Academy and Sabita forcompliance with the requirementsof the NQF.
Preview of 2003
Several postgraduate courses areplanned for 2003 covering thesubjects of Granular andCemented Materials, BitumenRheology, Introduction toConcrete Pavement Design andPMS for Gravel Roads.
Cooperation with the AsAc andSabita will be extended, especiallywith regard to the Training CourseFramework Workgroup, which alsofalls within the objectives of RPF.
One of the eagerly awaitedoutputs for 2003 is the stocktakingsurvey into the status of HigherEducation and Training (HET)within the pavement engineeringindustry. This survey wasconducted by the Chair, anddetails will soon be released onthe strengths and shortcomings ofHET in the industry as it currentlystands. �
63
After two years of operation,the year 2002 brought withit a much improved
understanding of how the AsphaltAcademy (AsAc) should positionitself in the blacktop industry toensure both that the objectives asstated in its mission are achieved,and that peripheral issues are notallowed to compromise primaryand long term focus areas.
AsAc’s Vision, Mission and Goalswere refined and clarified duringthe 2002, as follows:
Vision:
The Asphalt Academy is thepremier centre in southern Africafor knowledge transfer and skillsdevelopment in bituminousproduct technology.
Mission:
To collaborate with industry andinstitutions of research andlearning to:
• formulate, develop andsustain education andtraining programmes;
• promote continuousprofessional development;and
• advance best practice ineducation, standards, safetyand environmental issues.
Goals:
• to promote and encourage anadequate and consistentstandard of education andtraining at institutions oflearning to meet the needs ofindustry; and
• to provide knowledge transferfor the ongoing developmentof practitioners.
In terms of the above AsAc willnow concentrate on ensuringconsistency and quality ofeducation and training for newentrants to the industry, and onthe ongoing development ofpractising individuals throughcourses, seminars and workshops.
An important element of AsAc’sredefined position in the industrywas a re-evaluation, in 2002, of itslinks to and interaction with theConstruction Education andTraining Authority (CETA), theStandards Generating Board(SGB), and the Skills DevelopmentAct (SDA).
AsAc has decided not to becomean accredited institution oflearning in an effort to free itselffrom the ponderous bureaucracythat currently characterises theseinstitutions, and will now ratherrun and develop courses insupport of unit standards and
64
Best practice through an informedindustry
Asphalt Academyin 2002
Les SampsonCEO,
Asphalt Academy
qualifications developed by theindustry specifically to meet theirneeds. The unit standards andqualifications identified anddeveloped by the industry will, toa large extent, dictate trainingprogrammes, but that will notpreclude the development of othercourses and workshops for theindustry on an ad hoc basis as andwhen required.
Not being an employerorganisation, AsAc will also notcontract with employers andemployees to put the latterthrough learnership programmesand qualifications.
The academy’s strategic thrustareas were also given a sharperfocus in 2002, and have beenreduced to just two:
1. Education, Training andDevelopment
In terms of this action areaAsAc will:
Ensure that courses and curriculaoffered at institutions of learningare consistent and relevant toindustry needs through:
• regular assessment of coursecurricula;
• providing regular knowledgetransfer to lecturers, trainersand learners; and
• ensuring that courses andpostgraduate studies areproperly scheduled andcoordinated, and are aligned
with relevant legislation andquality standards.
2. Knowledge transfer topractitioners
To fulfil this objective AsAcwill:
• hold seminars and workshopsto disseminate best practice;
• publish and distributetechnical manuals;
• manage and maintainappropriate informationsystems;
• support and participate inCAPSA and RPF activities;and
• support Sabita and CSIRTransportek initiatives intoSADC countries.
In line with AsAc’s undertaking topublish and disseminate technicalmanuals, a major achievement in2002 was the launch of AsAc’ssecond technical guideline, InterimTechnical Guidelines: The designand use of foamed bitumentreated materials (TG2).
This guideline, which has extendedthe knowledge base associatedwith foamed bitumen treatedmaterials, has already generatedpositive local and internationalinterest, and is firmly entrenchingAsAc as southern Africa’s primaryeducation and training authorityfor the blacktop industry. Theguideline was launched at regionalseminars in Gauteng, KwaZulu-
65
AsAc will ensure that courses and curricula ... are consistent andrelevant to industry needs.
Natal, and the Eastern andWestern Cape in October.
Other highlights of a very busy2002, during which AsAc staged atotal of 27 courses, seminars andworkshops, and passed on bestpractice information to more than800 practitioners, included:
• 10 Introduction to Bitumencourses presented throughoutthe country and attended bymore than 200 delegates;
• Ultra-Thin Layer Asphalt(UTLA) workshops in Mayidentified a significantcommonality of need
between suppliers andspecifiers, initiating a Sabitaproject to develop genericguidelines for the design andconstruction of UTLAs. Theseare expected to be availabletowards the end of 2003;
• development of four newcourses for presentation in2003:
• application and constructionof surfacing seals (twocourses were presented in2002 with very positivefeedback;
• manufacture of HMA;• application and construction
of HMA;• surfacing repair and
maintenance.• a revised labour intensive
surfacing module to bepresented in 2003, as well ascourses on surfacing sealdesign (new TRH3) and
courses on the SAHMA designmethod, which will includesignificant sections onmodified binders;
• an advanced bitumen course,now being developed inassociation with StellenboschUniversity, to be presented inmid-2003 with Hussein Bahiras guest lecturer;
• initiation of a joint Sabita-Gautrans project, to beexecuted by CSIR, for thedevelopment of a technicalguideline on emulsion treatedmaterials. Publication andfeedback through AsAc isexpected by the end of 2003.
These, along with the existing ATCand BMOS modules, nowconstitute a comprehensiveportfolio of more than 50 coursesfor presentation around thecountry in 2003 - a significantincrease from the 27 modules thatwere run in 2002. It is expectedthat these courses will proveinvaluable in opening up the SADCmarket.
The activities and achievements ofAsAc over the past two years,linked to a critical appraisal ofpriorities, directions andresponsibilities, have thus resultedin a clear and focused distillationof AsAc’s strategic thinking, and apragmatic understanding of itscurrent position in the industry.
Plans developing from thisunderstanding will dictate AsAc’sdirection forward. �
66
Activities over the past two years have resulted in a clear andfocused distillation of AsAc’s strategic thinking.
The Past.
2002 was an exciting year forthe Society for AsphaltTechnology. This once
vibrant organisation hadessentially reached the crossroadsof survival - and the decision hadto be made to do something toensure continuity, or to closeshop. This followed a hiatus ofnine months between Councilmeetings, during which very littleCouncil activity took place,membership numbers began todwindle, and the regions wereoperating more or lessindependently, in isolation, andwithout coordination.
Furthermore, approximately 12months before this, Sabita founditself unable to continuesupporting SAT and ceased thesubsidy and secretarial supportwhich we had enjoyed sinceinception. Consequently, SAT wasset free and was compelled tooperate independently, and on atotally self-funding basis.
Having received a vote of supportfrom my employer Much Asphalt, Itook up the challenge of the SATpresidency in March 2002.
I was fortunate insofar as theimmediate past President Rob
Brown, and his team left the basicinfrastructure soundly in place,and I was able to pick up thereigns fairly easily.
The first item of business was toamend the Constitution to allowfor a change in the composition ofCouncil. This was previouslyagreed by the general member-ship at the Annual GeneralMeeting of 3 April 2001. Thepurpose was to limit the numberto eight councillors (fromeighteen). This restructuredcouncil was to consist of fourregional chairpersons, anHonorary Secretary and Treasurer,and two ex-officio members. ThePresident would, in future, beelected from the four regionalrepresentatives on Council.
From 27 March 2002, this new andstreamlined council comprised thefollowing:
• John Onraët, Chairman,Southern Region
• Gary Swart, Chairman,Eastern Region
• Basil Jonsson, Chairman,Central Region
• Duncan Smith, Chairman,Northern Region
• Duncan Mason, HonorarySecretary
67
Re-structured SAT setsnew levels of memberservice
John OnraëtPresident
Society for Asphalt Technology
• Elzbieta Sadzik, HonoraryTreasurer
• Piet Myburgh, Ex-OfficioMember (Sabita)
• Les Sampson, Ex-OfficioMember (Asphalt Academy)
A decision was taken that theSecretariat, (previously offeredand subsidised by Sabita), wouldbe out-sourced, and Pat Loots ofExecutive Focus was dulyappointed to carry out the SATsecretariat functions.Further rationalisation was putinto effect in terms of education,
membership, and technologydevelopment, all of which wereissues previously dealt with byspecific Council sub-committees. Itwas decided to devolve theseactivities to the regions and in sodoing, empower them accordingly.Council could then be left to focuson more important strategic issuessuch as:
• SAT’s national image;• membership growth and
propagation;• promotion of SAT in
sub-regions;• marketing;• relationships with Sabita and
AsAc;• finance.
An organisation such as ourscannot run on “fresh air” and afurther priority was to review themembership subscriptions, whichinterestingly, had remainedunchanged for eight years! Thecouncil therefore approved a
subscription increase effectivefrom 01 July 2002.
The newly convened Councildecided that it would beappropriate to review and focus onhow the aims and objectives ofSAT were currently beingaddressed, and to determinewhere there was room forimprovement. As a reminder, Itable these as follows:
• to promote knowledge ofasphalt technology and makeit available to members;
• to encourage and promoteimprovements in the practiceand standards of asphalttechnology;
• to promote discussion of allquestions affecting asphalttechnology;
• to watch over, support andprotect the status ofmembers of the Society.
One of the fundamental challengesfacing SAT was, and continues tobe, delivery to its members. Inthis context, it was necessary toreview the content and make-upof the membership base.
The Present
As a founder member of SAT, Ireflect back to the beginning andam starkly reminded of the factthat members of SAT consist ofindividuals who are students,laboratory assistants andtechnicians, asphalt plantoperators, asphalt technologists,
68
One of the fundamental challenges facing SAT was, and continuesto be, delivery to its members
engineers, company managers,academics, executives - in fact allpersons who have any interest atall in asphalt technology.
The delivery mechanisms arenewsletters, industry forums,access to education at all levels,interaction with other members atSAT technical functions, access totechnical information, publicationsand audio-visual material,attendance at and participation inindustry meetings, access toinformation on asphalt research,representation of members’ viewsat industry functions, and so on.
So we made it our objective to goback to basics, and encourage alllevels of members to participateand thus obtain some value frominvesting in and belonging to theSociety.
The Southern Region has alreadydeveloped the concept of the“Understanding Hot Mix Asphalt”workshop series, and this hasproved to be a winning recipe,attracting ever-increasing interestand attendance by all levels ofmembership. The growth ininterest of members, andnon-members alike, is demon-strated in the table below:
The workshop on Mix Design wasa follow-up discussion forumpertaining to the AsphaltAcademy’s launch of theirguideline document on the samesubject.
The final workshop in this currentseries will be held in early 2003 oncase studies on Hot Mix Asphalt,relating to all the previousworkshops. The series will thenprogress to another level, and willaddress bitumen emulsions andsurface seals.Another very successful initiativeof the Southern Region is theconcept of “Cocktail HourPresentations”, which consist of ashort presentation followed bydebate and discussion. TheEastern Region has also found amodicum of success with this typeof meeting.
The sessions start at 16h30, thusnot interfering with a normalworking day, and are self-funding.It is amazing what diversesubjects can be presented whenindividuals are given theopportunity to share successesand experiences with their peers.Technology Transfer sessions haveoccurred in both Central andSouthern regions, when visitors
69
Topic Date Held Attendance
Understanding Bitumen November 2000 82
Understanding Aggregate March 2001 90
Understanding HMA Design August 2001 102
Understanding HMA Production March 2002 111
Understanding HMA Paving June 2002 133
Understanding HMA Compaction September 2002 154
from overseas visited our shores.
Members of the Australian AsphaltPavement Association (AAPA)shared their technologies andeducation and training initiativeswith members. The AsphaltAcademy conducted seminars andcourses on the TRH 3 Manual,Foamed Bitumen, and Mix DesignGuidelines. The introduction of aguideline document on Ultra ThinLayer Asphalt (UTLA) is expectedin 2003. The delegates to thesesessions are mostly SAT members,and regional non-members
(potential future members!!)
Site visits are also a valuablemeans of membership delivery. Agood example of this was the visitto a Western Cape Contractapplying UTLA, attended by 85practitioners.
It is interesting to note that, afterthe activities described above,there has been a noticeableincrease in membershipapplications and this trendappears to be gaining momentum,something the Council isextremely pleased to see.
The Future
Service Delivery To Members
The highly popular workshopseries on Understanding Hot MixAsphalt has already begun in theCentral Region. On 10 October2002, Understanding Aggregateand on 26 November 2002,
Understanding Bitumen workshopswere held at Pretoria University.More than 80 people attendedboth functions, and plans are afootfor the continuation of thisworkshop series in this region. Itis pleasing to note that theEastern Region is also taking upthe challenge.
Finance
It is imperative that members arerecruited and pay their subs. Wecan only operate the Societysuccessfully if there is a proper
cash management process inplace. Much has been achieved inthis regard, and with our newauditors, KPMG, on board, astrong transparent financial policyis now in place. My thanks go toBenoit Verhaeghe for his pastcontribution as outgoing HonoraryTreasurer, and now have thepleasure of welcoming ElzbietaSadzik to this position.
Membership
The future of SAT remainsentrenched in the growth of itsmembership base. Withoutmembers, there is no Society,and it is the express strategicintention of the Council to ensurethat a growth path in membershipacquisition is maintained. Anaccurate and up to date databaseof members and non-membersis the key to success, andPat Loots has been tasked withmaking sure this is in place andavailable.
70
There has been a noticeable increase in membership applications
CAPSA’04
SAT will offer its resources to theCAPSA’04 conference bycontributing to the Technical TaskTeam and other logisticalactivities. The conference is to beheld at Sun City and promises toattract many local and overseasparticipants. SAT will be strongly“flying the flag” at CAPSA’04.
Marketing
There are many sub-regions,which are largely starved of SATattention, and it is a priority topromote SAT and servicemembers in these outlying
regions. Examples of this are PortElizabeth, East London, Nelspruit,Polokwane and Bloemfontein.
A SAT website will also shortly beavailable as an additional serviceto members and others. Ourobjective is to provide aninformative site which will give all“surfers” an understanding of thestructure, objectives and activitiesof SAT. Members will be able toaccess up-to-date technicalinformation, news and the latestdevelopment in our industry.
We also plan to publish a SATnewsletter on the site, and toprovide an interactive facility togive members the opportunity tocommunicate and express views.Also, non-members will be able to
assess the proven value of SAT inadvancing their professionalstanding. They will be able toapply for membership directlyfrom the website.
Technology Development
Creative ways are currently beingsought to initiate awards forexcellence in asphalt technology.
Education & Training
SAT will continue to hold theirregional workshops and seminarsin collaboration with the AsphaltAcademy (an institution geared forformal E&T).
As with all organisations such asSAT, success is the result ofteamwork and joint effort. Thosemembers who have supported SATduring the past nine months of mypresidential tenure have morethan earned thanks andappreciation. You have ourassurance that we are committedto making SAT a society all will beproud of!
Finally, I would like to close byexpressing my sincere gratitude tomy fellow councillors who havehelped me kick-start therevitalisation process, and whosesupport has been strong and loyal.Particular thanks goes to PatLoots, who held the threadstogether while we, so to speak,rebooted the system. �
71
An informative and interactive SAT website, which will include anewsletter, is currently on the drawing boards
Much Ad
With the memory of theVictoria Falls andCAPSA’99 still fresh and
vibrant in our minds, it seemsimpossible that CAPSA’04,scheduled for Sun City from 12-16September next year, can be just18 months away! This graphicproof of how quickly time can slipaway from us is a reminder thatnot only must planning of thismomentous event shift into topgear right now, but also that thedelegates who will attend shouldstart preparing themselves, theirpapers and their golf kit!
Some of us, of course, are alreadycelebrating the fact that after allthese years, CAPSA is finallymoving closer to Gauteng!
As usual, the upcoming CAPSApromises to be a great event, andwe hope to make this one a littlemore special! The theme isRoads - The Arteries of Africaand the various focus areas thatwill be covered include:
• Economic growth anddevelopment (ruraldevelopment, urban renewal,
asset management,employment);
• Efficient road provision andmaintenance (institutionalarrangement, risk sharing);
• Human capital employment(education and trainingschemes, broader economicparticipation);
• Best practice in design,construction andmaintenance (performancestudies, innovation,application of research,pavement surveillance,health, safety, environment);
The event will focus on the fullrange of issues in flexiblepavements, including design,construction, operations andmaintenance. Sessions andworkshops will be geared toprovide a platform for allrole-players in the bituminouspavement industry in Africaranging from road constructorsand maintenance practitionersthrough to owners, designers andresearchers.
The first call for papers will appearshortly, and for those of you with
73
CAPSA’04 planningmoves into topgear
’
Arthur TauteChairmanCAPSA’04
Developments since the previous CAPSA include significantchanges in the delivery of roads.
Internet access, details areavailable on the CAPSA website,asac.csir.co.za/capsa
Developments since the previousCAPSA include significant changesin the delivery of roads that nowinvolve road agencies, concessioncompanies and private mainten-ance contractors. We hope tohave wide representation fromthese bodies to obtain feedback onthe pros and cons of thesedelivery models.
In the technical field, there hasbeen widespread use of a range ofmodified binders and no doubtthere will be several papers thatcover the application andperformance of these products.Add the developments in foamedasphalt and Heavy VehicleSimulator Testing of this productnear Cape Town, and you alreadyhave a wide range of discussiontopics. This can be topped offwith issues related to the provisionof low cost access and distributorroads all over Africa and then theConference will offer enough tokeep everyone interested andinvolved.
In addition to providing a varietyof technical sessions, theconference will also provide avaluable opportunity for contactwith people in the industry fromall parts of Africa and the rest ofthe world. Sun City is uniquelyplaced to combine the technicaland social issues and the spouses’programme will also be carefullyput together. The Cascades will
be the conference hotel and wehave managed to obtain specialrates for their rooms, as well as atthe Cabanas. Those of you whothink you can play golf, get outthere and practice your swing, aswe will be organising some golf onthe Wednesday afternoon forregular, as well as occasional,players who would like to try andconquer one of the Sun Citycourses.
CAPSA’04 will coincide with asignificant milestone for thesouthern African roads industry.Celebrating its 25th anniversary in2004, Sabita will look back withpride on its role in facilitating thegrowth of our roads industry, theenrichment of its humanresources, and the evolution ofvaluable partnerships with bothauthorities and road sectorstakeholders.
The theme of CAPSA’04, and manyof the topics to be covered duringthe conference, reflect Sabita’sstrategic focus on the vitalinfrastructure development issuesconfronting the industry.Sustainability, the promotion ofregional standards, engagementwith government and thepromotion of best practice are justsome of these.
CAPSA’04 promises to be “TheEvent” in the 2004 global roadpavement calendar and should notbe missed. I would like to urgeyou to register early (via thewebsite asac.csir.co.za/capsa) toensure attendance. �
74
Critical evaluation andre-appraisal of existingsystems, structures,
procedures, practices andtechnology is a vital component ofa progressive and responsibleindustry.
Since its inception in June 2000,the Road Pavements Forum (RPF)has performed this function onbehalf of the broader roadsindustry, taking over the functionsand expanded objectives of theBituminous Materials LiaisonCommittee (BMLC) and theCementitious Materials LiaisonCommittee (CMLC)).
However, while the BMLC focussedlargely on keeping the industryinformed of findings in the field ofbituminous materials research,and providing a forum fordiscussion of industry issues, theRPF dramatically broadened itsscope to embrace relevantstrategic political and economicissues, as well as industry-specificproblems.
The perceived value of the RPF tothe broader roads sector wasacknowledged in 2002 with theaddition of the Aggregate andSand Producers Association ofSouth Africa (ASPASA) to itsmembership. With its supplying89-90% of the blacktop road
industry’s aggregate, ASPASA’smembership of the RPF may proveto be an alliance of significantimportance to the growth anddevelopment of the road sector.
The RPF’s representative base wasfurther broadened in 2002 withthe addition of the South AfricanReady Mix Association (SARMA) toits membership.
A critical element of this newindustry approach is coordinationand linkage with groupings thatare inextricably linked in theiroperations. This is a stance thatunderlines the road industry’s newperspective of playing an activepartnership role with majorstakeholders in the roads industry- including all tiers of government.
A resolution adopted at the 5thRPF meeting at Dikhololo (Brits) inNovember 2002 is an example ofthis new awareness of the impactof broader economic issues on itsgrowth and development.
The resolution, “That the RPF beregularly apprised ofdevelopments in NEPAD, includingpossible mechanisms for RPFmembers to participate in andaccess information on NEPAD” isalso indicative of the roadindustry’s evaluation of thepotential of cross-border
75
Road Pavements Forum embracesstrategic issues
contracting — particularly intoSADC countries.
An issue of major importance tothe roads industry was identifiedby Sabita executive director PietMyburgh, who delivered apresentation focussing on theobsolescence of currentspecification documents, and thefact that most of these no longerreflect best practice. Following thispresentation the RPF adopted amotion that the task group onRoad Building Specifications beintegrated into the activities of thetask group on NationalSpecifications and Guidelines.
Addressing industry concernsabout the inconsistency of, andlack of confidence in, laboratorytest results, the RPF also approved
the formation of a working groupon Laboratory Testing andAccreditation, which will liaise withthe South African NationalAccreditation Service (SANAS) toexplore mechanisms and meansby which the proposed NationalProficiency Testing Scheme can beimplemented (See Page 109).
The November meeting of the RPFendorsed the Bitumen Price Index(BPI) developed under Sabitasponsorship, and directed theworking group to draft appropriateinsertions into contractdocuments, and to liaise withSAFCEC to facilitate itsimplementation. (See Page 80).
An important function of the RPFcontinued to be its facilitating rolein identifying technologydevelopment needs, the provisionof a forum for interaction toadvance best practice, and thedissemination of new technologies.
The Foamed Bitumen workinggroup was active in the past yearin promoting and accepting thedevelopment and publication, bythe Asphalt Academy, of theInterim Technical Guideline; Thedesign and use of foamed bitumentreated materials (TG2) (reviewedon page 84).
This valuable addition to, andextension of, current foamedbitumen technology, is now beingevaluated by the industry(including HVS tests in Cape Town
- see page 97). The working grouphas now been suspended untilsufficient field testing informationis available to allow a revision ofthe draft guideline.
Acknowledging the increasing useof sprayed hot binders, in additionto emulsions and cutbackbitumens, the RPF meeting atMagalies Park Country Lodge inMay 2002 accepted that outdatedspecifications and documentationare currently militating againstgood engineering practice in thefield of binder distributors.
Essential to the RPF’s ongoingsuccess is the willingness on the
76
The RPF dramatically broadened its scope to embrace relevantstrategic political and economic issues.
part of various sectors in theindustry, and those with aninterest in technologydevelopment and transfer, tocooperate and provide this forumwith healthy debate and
contributions — all in the interestof best practice. The RPF’sstrength lies in its flexibility andwillingness to be sensitive to theneeds of the industry, and toadapt accordingly. �
77
78
79
3New
Developments
The Bitumen Price Index (BPI)developed under Sabitasponsorship was endorsed by
the Road Pavements Forum (RFP)in November and will be includedin contract documents from 2003.This index will ensure thatbitumen prices can be adjustedthroughout a contract period toaccurately reflect price fluctuationscaused by foreign exchangevariations, the rise and fall ofcrude oil prices, or local influencessuch as the PPI.Designed to be equitable, fair andtransparent, the BPI will bepublished monthly, enablingcontract prices to be adjusted onan ongoing basis.
The proposal to develop a BPI wasinitiated by the Southern AfricanBitumen Association (Sabita) inthe wake of a CompetitionsCommission ruling that effectivelyscrapped the publicised WholesaleList Selling Price (WLSP) ofbitumen in August 2000. SinceSouth Africa is a price taker ratherthan a price maker, the BPIconcept was devised to give roadbuilders an adjustmentmechanism to compensate forprice increases brought about byglobal trading conditions, and to
ensure that road owners enjoy thefull benefits of improved foreignexchange rates and crude oilprices.
The introduction of a BPI is notan attempt to introduce pricecontrols or regulation. On thecontrary it is expected that thesystem will do the opposite, andencourage both price flexibilityand competition.
In the past, with no relevant localprice indicator, the only way toensure that contracts fairlyreflected price fluctuationsthroughout the contract periodwas by reference to the WLSP.
The BPI is a significant stepforward from this position since itallows the industry not only tocompensate for price increases,but also to capitalise on thepotential benefits of favourablemovements in indicatorparameters - to the ultimatebenefit of the taxpayer. Theintroduction of a BPI shouldtherefore be seen in the context ofthe blacktop industry’s ongoingefforts to achieve cost-effectiveroad provision for the benefit of allroad users.
80
Bitumen Price Index (BPI)adopted for roadsindustry
Piet MyburghExecutive Director
Sabita
In the past... the only way to ensure that contracts fairly reflectedprice fluctuations was by reference to the WLSP.
Sabita initially proposed theintroduction of a BPI at the RPF inMay 2001. The rationale was thatwith the demise of the WLSP, norational, widely acknowledgedbenchmark existed for contractprice adjustments of a productexposed to foreign exchangefluctuations, changes in crude oilprices and local influences.
The objective was to develop atransparent and defendablemechanism of price adjustment fora product driven largely by globalfactors, irrespective of discountagreements negotiated between
particular suppliers and theircustomers. (It is this aspect of thesystem which is expected topromote price flexibility andcompetition.) Initial studies soughtto establish how the WLSP ofbitumen varied compared to thelanded cost of related hydrocarbonproducts {eg 180cSt marine fueloil (MFO)}, and to create a modelwhich simulated WLSP movementsover the period January 1989 toSeptember 2000.
This preliminary investigationshowed a very close correlationbetween the bitumen WLSP andthe landed price of MFO, and thelimited scatter shown in Figure 1below was attributed to stepwiseadjustments to the WLSP and tothe effects of other factors such asinflation.
It was therefore considered logicalto conclude that, in anunregulated environment, thedriving force of input cost toproduce a ton of bitumen was to alarge extent dependent on thelanded cost (in SA Rands) of a
similar petroleum product.
It was also thoughtreasonable to assume thatthe influence of local inputcosts of production andstorage should also beincorporated into themodel through a factorsuch as PPI.
The following proposedsimulation model, whichprovides a periodic priceadjustment factor, wasdeveloped:
where f = 0.6i = current monthi-1 = previous month
This formula was used to arrive ata factored price, which was thencompared to the WLSP for theperiod January 1998 to August
81
600
400 600 800 000 1200 1400
700
800
900
1000
1100
1200
1300
1400
1500
1600
Bit
um
en
WLS
PR
/to
n
Correlation MFO - Bitumen (Durban)
(WLSP Jan 98 - Sept 00)
Y = 0.9075x + 348.86R = 0.9662
2
MFO R/ton
Figure 1. Correlation MFO-bitumen
WLSPi = f*MFOi/MFOi-1 + (1-f)*PPIi
WLSPi-1 PPIi-1
2000. Again, a very closecorrelation was apparent. The nextstep was to plot the market priceagainst the simulated price for thesame period, and a correlationvery close to unity was shown.Follow-up studies of the BPI modelrelative to price movements in themarket between January 2001 andNovember 2002 had confirmed theaccuracy and applicability of thefollowing BPI model:
Where: i = current monthi-1 = previous monthj = month of latest
available PPIj-1 = month before
latest available PPI
The working group pointed outthat the advantage of using a BPIas a monthly percentage changewas that it is independent of thecurrent price of bitumen, which isnot constant across the board.Development work on the BPI ledthe working group to the followingconclusions:
• the model simulates actualmovements in the WLSP verywell;
• it is a suitable mechanism forintroduction into contractdocuments;
• the introduction of local PPIimproves the simulationmarginally;
• in the absence of a WLSPthere is little alternative to aBPI;
• the notion that presentationof supplier invoices as a
means of substantiation ofprice increases is probablynaive;
• the method derived is animprovement on the WLSPbecause it indicates the needfor price reductions, withaccompanying benefits.
It was therefore recommended tothe RPF in May 2002 that:
• the BPI (basedon the pastmonth’sbunker pricesin Rands and
the previous month’s PPI) beapplied to all bituminousproducts (this excludes tars);
• for contractual purposesbitumen be regarded as a“special product” subject to“rise and fall”;
• monthly adjustments bemade in terms of thepublished PPI and the ratesentered by the contractor onthe tender form.
The working group does notforesee any problems with theimplementation of the BPI, andbelieves a workable system can bedevised. It should be notedhowever that options are still openon how to apply the index tobinders such as cut-backs,emulsions and modified binders.
The rise and fall can either becalculated on the net bitumenvolumes or, in the interests ofsimplicity, the index could beapplied to the entire product(s). Itis likely that the most favourableapplication of the BPI to cutbacks,modified binders and emulsions
82
BPI = {0.6*(MFOi-MFOi-1) + 0.4*(PPIj-PPI j-1)} *100MFOi-1 PPIj-1
will emerge through practice.
However, it is clear at this stagethat tender information for priceadjustments will need to includethe following:
• applicable materials, egpenetration grade bitumen,emulsion, cutback ormodified binders;
• binder type and concentration(optional for emulsions andmodified binders);
• Price for the base month(excl. VAT);
• application rates for tenderpurposes;
• variations ordered.Recommendations proposed bySabita and adopted by the RPF in
November propose:
• that the RPF accept theconcept of a BPI andrecommend its introductioninto contracts;
• that a task team beappointed to draft insertionsinto contract documents tothat effect; and
• that the matter be taken upwith the South AfricanFederation of CivilEngineering Contractors(SAFCEC) to facilitate itsintroduction.
It is anticipated that the BPIsystem will be introducedinto contract documentsduring 2003. �
83
POWER CONSTRUCTION ROADS AD HERE
In September 2002, the AsphaltAcademy released TechnicalGuideline 2, “Interim Technical
Guidelines: The design and use offoamed bitumen treatedmaterials” (TG2).
TG2 is a comprehensive guidelinepresenting the latest available,published information on thedesign, construction andperformance testing (in thelaboratory and under the HeavyVehicle Simulator) of foamedbitumen treated materials.
It also includes the knowledge andexperience of the authors andreview panel regarding thebehaviour and performance ofsuch materials. It should be notedhowever that TG2 is intended asan interim guideline, and will beupdated as more informationbecomes available.
The guideline was compiled byKim Jenkins (University ofStellenbosch), Dave Collings(Loudon International), HechterTheyse (Transportek, CSIR) andFenella Long (Transportek, CSIR)for the Gauteng Department of
Public Transport, Roads and Works(Gautrans), and Sabita. Twentyindustry representatives exten-sively reviewed the guideline,which contains five Chapters andtwo Appendices:
Chapter 1 — IntroductionChapter 2 — Selection criteria for
identification ofsuitable projects
Chapter 3 — Mix designChapter 4 — Structural designChapter 5 — Construction aspectsAppendix A — Laboratory test
methodsAppendix B — Mechanistic-
empirical pavementdesign for foamedbitumen treatedlayers
Chapter 2 discusses the criteria forselecting suitable projects, riskassessment, the recycling process,traffic and environmental benefits.Chapter 3 discusses the mixcomponents and providesguidelines for the selection
84
Interim TechnicalGuidelines: (TG2)
A review andevaluation
Fenella LongResearcher
CSIR Transportek
Hechter TheyseResearcher
CSIR Transportek
TG2 has filled a gap in industry, both here and abroad, and is amuch needed guideline.
thereof, as well as the procedureand mechanical tests for theselection of the optimum foamedbitumen content. The proceduredifferentiates between Category Aand B, and Category C and Droads, with a more detailed mixdesign procedure recommendedfor Category A and B roads. Amaterial classification systemconsisting of four material classesis introduced. The classificationsystem depends on both UCS andITS values, in an effort to measureboth the compressive strength andflexibility of the material.
Chapter 4 reviews the typicalbehaviour of pavements withfoamed bitumen treated layers,and a mechanistic-empiricalapproach for designing thepavement structure is presented.The pavement life is determined intwo phases - effective fatigue andpermanent deformation. Theeffective fatigue life implies areduction in the initial stiffness ofthe material, until an equivalentgranular state is reached. At theend of theeffectivefatigue life,the layer isnot necess-arily in acracked state.The moreflexible themix, thelonger theeffectivefatigue life.
Catalogues fornewconstruction and design charts fordeep in situ recycling are included.
The design charts requireknowledge of the strength of thepavement to be recycled. Thecatalogues and charts arepresented for two of the fourmaterial classes. As databecomes available, additionaldesign catalogues and charts willbe introduced in future revisions.The full mechanistic-empiricaldesign approach, includingtransfer functions andrecommended input values, ispresented in Appendix B.Chapter 5 discusses the criticalaspects of the construction offoamed bitumen treated layersand provides recommendations forquality control. The chapterfocuses primarily on deep in siturecycling.
The Guideline was launched at aseries of workshops in Gauteng,KwaZulu-Natal, Eastern Cape andWestern Cape during September2002. Approximately 250 peopleattended the four workshops,which consisted of presentationson the main sections of the
guidelines bythe authors,with ample timefor questionsand discussion.The workshopswere facilitatedby LesSampson, CEOof the AsphaltAcademy(AsAc).
The workshopswere successful,and favourable
feedback was received. It was feltthat TG2 had filled a gap in
85
industry, both here and abroad,and was a much needed guideline.Commentators also remarked thatthe level of detail in TG2 wasappropriate.
Key points
Key points were raised fordiscussion at most of theworkshops. Some of these keypoints are listed below:
• Compaction: Thedifferences betweenlaboratory and fieldcompaction can be fairlysignificant, and therelationship between the twoneeds to be betterunderstood. It wasrecommended that refusaldensity type laboratorycompaction (i.e. Kangohammer) was preferable tomodified AASHTOcompaction. Field densityspecifications should specifyan achievable density, butallow an extra-over if agreater density is achieved.
• Laboratory mixing:The effects of temperature inthe laboratory during mixingneeds to be considered. Itwas also emphasised that themoisture contents foroptimum mixing andcompaction are essential forgood specimen preparation.This should be carefullymonitored in the preparationof all laboratory testspecimens. A procedure for
determining these optimummoisture contents is given inTG2.
• Fillers: Improvedunderstanding of the effectsof different filler types, bothactive and inactive, isnecessary. And, it must beensured that the mix andstructural design proceduresare applicable to all fillertypes.
• Measure of flexibility:The ITS test is not the besttest to measure flexibility,and another test is neededfor use in standardlaboratories. One possibilityis the four point beamstrain-at-break test. Theease of adapting this test forstandard laboratories needsto be investigated.
• Curing: Curing proceduresneed to take cognisance oftemperature and moisture. Asimple procedure thatprovides reliable equilibrium
moisture content results isneeded. Curing is an areathat requires furtherresearch.
• Moisture damage: There isa need for more fundamentalunderstanding anddevelopment/refinement oftesting procedures formoisture damage in foamedmixes.
86
A procedure for determining optimum moisture contents is given inTG2
• Resealing: The estimatedresealing times given in theguideline are thought to beconservative.
• Calibration of the structuraldesign models is essential,especially with field data.
• Trial sections: Theconstruction of trial sectionsare very important.
• Database: There needs to bea database of foamingactivities in South Africa.
• Emulsion treatedmaterials:There is a need to update theguidelines for the design anduse of emulsion treatedmaterials to the same levelas foamed bitumentreatment.
It is envisaged that TG2 will beupdated within two years. Themajority of the updates are likelyto focus on modifications to themix design procedure, where
necessary, and validation andmodification of the structuraldesign models. An extensiveHeavy Vehicle Simulator andlaboratory testing project isunderway on the N7 in theWestern Cape. This project willprovide much of the datanecessary to update and validateTG2 — a process dependent onfeedback from the users of theguidelines. These practitionersare asked to forward comments tothe Asphalt Academy([email protected]).
A project is also currentlyunderway to compile a companionTechnical Guideline for emulsiontreated materials. The availabilityof both guidelines will allow aunified approach to the design andconstruction of bituminous treatedmaterials, and will provide aplatform for the rationalassessment of the most applicablebituminous binder for anyparticular project. �
87
Background
In 1997 a technique wasdeveloped, by Kim Jenkins andLucas Ebels at the University
of Stellenbosch, for themanufacture of bituminous pavingblocks. The technique incorporatedthe stabilisation of locally availablenatural gravel with bitumenemulsion and foamed bitumen andthe compaction of paving blocksfor road construction.
This research was carried outunder the supervision of theSabita Chair in Asphalt PavementEngineering at the University ofStellenbosch (US).
The first attempts atmanufacturing cold mix pavingblocks and constructing trialsections with these blocks weresuccessful, but far from optimal.The block manufacturing systemdevised for the project wasextremely simple, and worked wellin practice. It included acompaction mould grid for theblocks using a collapsible grid ofsteel plates that allows blocks ofup to 100mm in height to bemanufactured and immediatelyextracted. An electrically poweredKango Hammer 167 (r) with acompaction foot of 100mm x200mm in plan, was used to
compact the cold mix placed inthe cells. Compaction times of 30to 40 seconds were commonlyrequired to achieve 95% ofModified AASHTO density.
Scope for improvement of the coldmix block technology wasparticularly evident with respect tothe nature of the materials andthe mix design used. G7 qualitygravels treated with 3,6% offoamed bitumen and emulsion(residual binder content) wereused for the full-scale trial section.The marginal nature of thematerial resulted in prematureravelling and aggregate-loss fromthe blocks. This is apparent in therelatively low resilient stiffness
88
Cold Mix Paving Blocks:Innovations for developingcommunities Kim Jenkins
Head, SANRAL Chair inPavement Engineering
University of Stellenbosch
Figure 1. Compaction of Cold MixBlocks with Kango Hammer®
values measured for the blocksmanufactured in laboratory andfield conditions, as shown below.
Further Trials: Phase 2
In 2002, additional trials werecarried out in the laboratory at USusing better quality materials, asan undergraduate researchproject. A G2 quality Greywacke
(Hornfels) aggregate was treatedwith approximately 3,4% grossemulsion and blocks weremanufactured from the mix.Various types of emulsion wereproduced in the laboratory usinga Rashig mill to investigate theinfluence of emulsion type onthe block properties.
The second phase of researchproduced blocks with improvedtensile strength and ravellingresistance. Tensile strengths of600 to 840 kPa were achieved forthe most effective emulsionbinders. This could have beenfurther enhanced had higher
binder contents been used, whichwould have further increased theblock resilient modulus.
Accelerated pavement testingusing the Model Mobile LoadSimulator (MMLS3) providedevidence that the use of suitablequality aggregate could notablyreduce the ravelling susceptibilityof the cold mix pavers. Mouldingof the joints with traffic andimproved load transfer conditionsbecame apparent for thesevisco-elastic blocks.
Although the second phaseresearch project was of a limitednature, it confirmed some of thebenefits that cold mix blockpavements enjoy relative to blocksmanufactured from othermaterials. These include theperformance properties of flexiblepavers, simple procedures formanufacure suited to SMMEs, and
economic benefits. If the bindereconomy, the material andtransport costs are balancedagainst the extra compactiveeffort requirements of cold mixpavers, a realistic benefit is stillachievable.
Cold mix paving blocks areconsidered to be a viabletechnique not only for labourintensive construction, but alsoconventional construction ofsegmental pavements. Potentialexists for their application onmedium to low traffic roads,parking areas and drivewaypavements. �
89
No traffic
With traffic
Foam
+ce
m(si
te)
Emulsion
+ce
m(la
b)
Emulsion
- cem
(site)
Emulsion
+ce
m(si
te)
0
200
400
600
800
1000
Block
Resilient
Modulus
(Mpa)
800
Figure 2. Influence of traffic on cold mixblock stiffness
Cold-mix paving blocks are...a viable technique for theconstruction of segmental pavements
1. Introduction
The International Society forAsphalt Pavement’s (ISAP)premier event, the 9th
International Conference onAsphalt Pavements (ICAP), washeld at the SAS Falconer Hotel inCopenhagen, Denmark on August17 - 22 20021.
More than 450 delegates and 70associate delegates from 51countries, including 22 sponsorsand 20 exhibitors, took part in theconference, which was precededby two days of tutorials, all wellattended by novices and expertsalike. These covered topicsranging from mechanisticpavement design, back
calculation, new AASHTO 2002Pavement Design Guide toAccelerated Pavement Testing(APT), mix design and roadsurface characteristics.
Nine topics were covered duringthe conference, setting the scenefor the technical presentations anddiscussions that followed inplenary and parallel sessions overthe following four days. A total of360 abstracts were received by
ISAP. The authors of 122 of thesewere offered the opportunity tosubmit full papers for peer reviewand for presentation at theConference. A pre-conferencecompact disc (CD) with all theaccepted papers was also handedout to delegates duringregistration.
The opening session wasaddressed by Thomas Egebo ofthe Danish Ministry of Transport,the Mayor of Fredericksburg (theCopenhagen Municipality wherethe conference was held), HenningChristiansen, Director General ofthe Danish Road Directorate, andProf. Stephen Brown of the
University of Nottingham, who isalso Chairman of ISAP.
Brown reminded the audience ofthe significance of this series ofconferences and of the veryimportant papers which had beenpresented over the previous 30years. Delegates were invited tojoin ISAP in order to supportfuture conferences and theexpanding program of activitiesset out in the Society’s strategic
90
The Ninth International Conference onAsphalt Pavements, Copenhagen,November 2002
An overviewMorris de Beer
Project ManagerCSIR Transportek
The lack of papers addressing construction and implementationissues ... is still a major shortcoming
plan. ISAP had a well-locatedstand in the technical exhibition,which was well organised andsupported by Gerhard Kennepohl.
All coffee breaks and lunches weretaken in the exhibition area,allowing delegates to meet and totake full advantage of thenetworking opportunities.
2. Plenary sessions
The plenary sessions were kickedoff by Dr Per Ullidtz who deliveredthe 4th ISAP Distinguished Lectureentitled “Analytical Tools for theDesign of Flexible Pavements.” Hereferred to the increasinglypowerful computer techniques nowat the disposal of researchengineers, and discussed the needto model reality, taking properaccount of the response ofpavement materials to repeatedloading.
The use of the Distinct ElementMethod (DEM) for modellingparticulate or granulate media wasdemonstrated. (See Figure 1.) Inthis method each grain isconsidered as a discreet particleand not as a homogeneouscontinuum that is associated withother methods. He also explainedthat modelling pavements onlycan never replace physical testingand evaluations.
Other plenary sessions coveredperpetual pavements, noise andthe AASHTO 2002 Mechanistic-Empirical Pavement Design Guide.See Section 4 for moreinformation on the new Guide.The parallel technical sessionsincluded presentations by authorsand were followed by discussions.The themes of the conferenceincluded:
• Design;• Performance;• Construction and
maintenance;• Accelerated testing;• Environment; and• Thin surface technology.
Among the lessons to be learntwere:
Firstly, that too many papers mayhave been crammed into thetechnical sessions, leaving little orno time for discussion andevaluation.
Secondly, the allocation of papersto each session was not alwaysaccording to the themes. Thenumbers of papers allocated toeach of the conference topics,together with some summary
91
Figure 1: Example of a 2-D computer-generated granulate (particulate) media
for layer analysis demonstrated byDr Per Ullidtz
remarks at the end of theconference by Prof. Brown, areindicated in Table 1 (page 96).
3. Analysis of papers bykeyword
As is often the case it is verydifficult to categorise papers intospecific conference topics.However, a more detailedelectronic search revealed thatpapers could be categorised byreferring to certain keywords usedby the authors in their papers. Thenumbers in brackets in Table 1indicate the number of papers inwhich keywords relating to theConference Topics appear in thetext of the papers presented.
Based on the above method ofevaluation by keywords, a furtherbreakdown of the officiallyaccepted 122 papers is illustratedin Figure 2. This breakdown isbased on selecting typical“pavement related” keywords
found in the conference papers,including the references given. [Itshould, however, be noted thatthe absence of a keyword from apaper does not necessarily meanthe topic was not discussed.]
Figure 2 indicates that the largestnumber of papers referred tokeywords such as “pavements”and “design”. However, it isimportant to note that 91 papersreferred to rutting (or plasticdeformation) of asphalt materials,by comparison with 27 papers thatreferred to traffic-associatedfatigue cracking.
Could this be a sign that the worldis struggling with stable asphaltmixes as opposed to flexurefatigue of these layers?
On the modelling side it seemsthat realisation of the non-uniformity of tyre loading on thepavement, as well as of thenon-linearity of material properties
92
Number of papers referring to keywords in text
Pavements
Design
Rutting, Plastic
Models
Pavement Design
Rehabilitation
Fine Elements
Linear Elastic
Guidelines
Fatigue Cracking
Backcalculation
Contact Stress
Thermal Cracking
Materials Design
New Methods
Keyw
ord
s
9th ICAP 2002, Copenhagen, Denmark.August 17 - 22, 2002
Figure 2: Breakdown of 122 papers based on selected keywordstypically used in the papers presented at the 9th International
Conference on Asphalt Pavements (9th ICAP) in Denmark.
(e.g. visco-elasticity and plasticity,stress dependency, etc.) isincreasing. {36 papers referred tothe Finite Element Method (FEM)by comparison with 30 papers thatreferred to Linear Elastic Modelling(LEM)}. A contributory factor hereis also the ever-increasingcomputational power of modernday computers.
In addition, there were 10 papersreferring to tyre pavement contactstress issues, in contrast to onlythree papers on the same topic atthe previous 8th ISAP conferenceheld at Seattle in 1997.
It was interesting to note that in aChinese paper it was stated(slightly modified by the presentauthor) that “In the case ofnon-uniform contact pressures,
the pavement distress caused byoverloaded light vehicles may bemuch greater than that caused bynormally loaded heavy vehicles.”
As far as implementation isconcerned, only 4 papers referredto this topic, although 90 papersreferred to construction, ingeneral. It seems that the lack ofpapers addressing constructionand implementation issues to“bridge the gap” is still a majorshortcoming of these traditionallytheoretically orientatedconferences.
It is hoped that the challengesgiven in Table 1 will be furtheraddressed at future conferences
such as the (next) 10th ISAPConference to be held in Quebec,Canada, in 2006.
4. 2002 AASHTOPavement Design guide2
In both the pre-conferencetutorials and in a plenary session,reference was made to the newmechanistic-empirical (M-E) basedAASHTO 2002 Guide. The plan isthat the U.S. National HighwayResearch Program (NCHRP)Project 1-37A will develop the2002 Guide for the Design of Newand Rehabilitated PavementStructures, with the emphasisbeing on design procedures forpavement rehabilitation. TheGuide will also focus on avoidingpremature failures as indicated inFigure 3.
The multi-year development of the2002 Guide will embrace thefollowing principles:
• Development will be based onexisting models, databasesand, to the greatest extentpossible, on soundmechanistic principles forboth flexible and rigidpavements.
• The Guide will reflectstate-of-the-art pavementdesign procedures availablein 2002.
• It will provide the foundationfor mechanistic-empirical(M-E) design for the next 10to 25 years. It will strive to
93
Encouraging advances have been made in the use of the FallingWeight Deflectometer.
set a worldwide standard forpavement design.
• Within the framework of theavailable technologies, theGuide will provide pavementdesigners with the greatestpossible flexibility to applylocal design options andapproaches.
• It will provide an equitabledesign basis from thestandpoint of pavement type.
• It will address all new andrehabilitation design issues.
• It will be presented in auser-friendly manner.
• Procedures can be calibratedto local pavementperformance.
This project calls for the develop-ment of a design procedure basedon existing technology. However,several factors make the projectvery complex:
(a) This is the first compre-hensive mechanistic-empiricalprocedure for the design ofpavement rehabilitation. Variousgroups have developedmechanistic-empiricalprocedures for thethickness design of newpavements and asphaltconcrete overlays, butnone address all theexpected types of distresstogether with appropriatenon-overlay designs. Theproposed design procedurewill address all thecurrently usedcombinations of pavementtypes and materials, aswell as a wide variety ofexpected distress types
and numerous rehabilitationoptions.
(b) The mechanistic-empiricaldesign procedure included in the2002 Guide will further providetools to enable the designer toevaluate the effect of variabilityin materials (both inherentvariations and those due toconstruction procedures) onpavement performance.
The 2002 Guide will provide arational relationship betweenconstruction and materialsspecifications and the design ofthe pavement structure. Sincethe mechanistic procedures arebetter able to account forclimate, ageing, today’smaterials, and today’s vehicleloadings, variation inperformance in relation todesign life should be reduced, asindicated by the dashed linedistribution in Figure 3.
Informed decision making
This feature will allow agencymanagers to make more informed
94
Design Life
PrematureFailures
Observed Performance(Current Designs
Desirable
Construction TIME
PERCEN
TO
FPRO
JECTS
REH
ABIL
ITATED
Figure 3: Performance of existing pavementdesigns (from http://2002designguide.com)
decisions based on life cycle costsand cash flow. Based on aprobabilistic-based life-cycle costanalysis (LCA), it is conservativelyestimated that improvedpavement design procedures willreduce the number of prematurefailures as is indicated in Figure 3.This will result in average annualsavings of pavement rehabilitationcosts in the USA of $1.14 billionper year (1999 costs) over thenext 50 years.
This analysis was based on adesign life of 20 years and theassumptions that the percentageof early pavement failures(pavement lives of less than 10years) would drop from 5 to 0,5
percent. It was further assumedthat the range of performancelives for the remaining pavements,10 to 30 years in terms of currentpractice, would be extended to 15to 30 years using the 2002procedure.
5. SUMMARY
In summing up the conference,Prof Brown reviewed progress inasphalt pavement technologysince the 7th and 8th Conferencesin Nottingham and Seattle,respectively. Encouragingadvances had been made in use ofthe Falling Weight Deflectometer,computing power for pavementand materials modelling andaccelerated pavement testing.Stepwise progress had been madein most other areas. It is theauthor’s opinion that, although
this was not a “breakthrough”conference, there were manyindividual papers with goodinformation that could be applied(with adjustment) both in theoryand practice. Bridging the gapbetween research and practicecontinues to require attention andeducation.
A second CD is planned for this9th International Conference,which will include the officialconference proceedings, allpapers, and photographs. Formore information please visithttp://www.asphalt.org.The next International ISAPConference will be held in Quebecin 2006. Representatives of the
organising group, led by Guy Doréof Laval University, described theimpressive progress already madein preparation for the event.
The Canadian Ambassador toDenmark hosted a reception at hisresidence for a large party ofdelegates to mark this upcomingevent. Ray Brown from theNational Center for AsphaltTechnology (NCAT) at AuburnUniversity (Alabama) outlinedplans for the first ISAPInternational Conference on“Design and Construction of LongLasting Asphalt Pavements” to beheld at Auburn in June 2004. �
1. Most of the content of this introduction was taken from“The ISAP Reporter”, Issue No. 27, October 2002,available with more information onhttp://www.asphalt.org
2 The content was taken from: “Summary of theproposed 2002 pavement design guide”, NCHRP Project1-37A, K.H. McGhee, P.E. Co-P.I. (October 1999).
95
The 2002 Guide will provide tools for evaluating the effect ofvariability in materials.
96
Conference Topics Number ofpapers in each
session*
Technical remarks on papers presented for each of theconference topics
Design and Modelling 51 (86) Incremental Progress since 1997 (Seattle); Mechanistic-Empirical (M-E) : AASHTO 2002 awaited; Good work on durability;
Reflection cracking - modest progress; Good work on healing and interlayer bonding; Field testing to continue for
calibration;Foundation — slow to implement known principles of basic soil mechanics; Subgrade - elastic strain and CBR still
with us; “Shakedown” theory - not new but renewed interest; Non-linearity — more important to quantify its effects; Field
testing and evaluation to be increased; Top-down cracking in thicker AC layers still problematic - causes and modelling
problematic; 3-D FEM — increased usage to cater for non-linearity of road material and non-uniformities of tyre-pavement
contact stresses for both field and laboratory evaluations; New damage concepts for AC materials/layers; Importance of contact
stress distributions and tyre pressures; Improved pavement response models; Use of Weigh-In-Motion (WIM) results in M-E
pavement design.
Performance 29 (113) Pavement Management Systems; Innovative field measuring techniques; Perpetual pavements: not a new concept - renewed
interest (Up-coming Intermediate 1st International ISAP Conference in Auburn, Alabama USA - June 7-9, 2004). Contractual
implications and guarantees; Aim to have approximately 5 percent of network consisting of long-lasting (perpetual) pavements;
Thin (40 mm) and ultra-thin (15 mm to 25 mm ) surfacings have become more popular in Europe.
Construction and
Maintenance
15 (52) Implementation slow but steady; Contractor involvement helpful; Increased use of FWD during construction; Increased use of
Life Cycle Analysis (LCA) in the planning of road maintenance.
Accelerated Pavement
Testing (APT)
14 (21) Increased use and good progress internationally; Implementation: SA example in M-E design guidelines for Foamed Bitumen,
Improved specifications; Dynamic loading and “shakedown” testing and analysis; Use of in-situ instrumentation such as
vertical and horizontal pressure cells - also during construction. Effect of speed on pavement response.
Environment 13 (78) Good progress; Importance of noise reduction - “twin-asphalt-layer” use in Denmark; Use of Foamed Bitumen (FB) in
recycling - role of cementitious binders to be quantified further in these FB mixes; Mechanistic modelling possible in new
AASHTO 2002 Guide; Frost effects - improved understanding.
Innovation Pore pressure concept for asphalt materials; Improved understanding of “Shakedown theory” in labouratory; Durability;
Interface bonding and effects - constitutive modelling of interfaces; Damage modelling; Deep porous AC layers (noise
reduction, drainage); Pay factors for contractors - max. 5 percent bonus payment; Pavement inspection using the “borescope”.
Challenges for ICAP 2006 in
Quebec
Quieter pavements; Longer lasting (perpetual) pavements; Increased implementation of research findings; Fresh look at
reflection cracking; Incorporation of basic soil mechanics in subgrade design; Validate concepts with APT and “Smart roads”;
Need for “simple” laboratory tests; Training and communications/skills transfer.
Total Number of papers 122
Table 1: Broad categorization and summary remarks on 9th ICAP papers accepted for publication.
* ( ) = Number of papers in which the keywords related to the Conference Topics appear in the papers accepted for publication.Legend: AC = Asphalt Concrete; FWD = Falling Weight Deflectometer ; CBR = California Bearing Ratio; FEM = Finite Element Method.
Background
In last year’s edition of theSabita Digest Dr. Fenella Longreported on the Heavy Vehicle
Simulator (HVS) and laboratorytesting performed on emulsion andfoamed bitumen treated materials,which took place in Gauteng onroad P243/1.
The testing and compilation ofconstruction experience resulted inguidelines titled Interim TechnicalGuideline: The design and use offoamed bitumen treated materials
(TG2) published by AsphaltAcademy in September 2002.
The guidelines deal with aspectssuch as:
• Selection criteria foridentification of FB projects
• Mix design• Structural design and• Construction aspects
A shortcoming of these guidelinesis that the HVS and laboratorytesting were conducted only onone type of material, the ferricretefrom P243/1. The quality of thismaterial can be described asmoderate and was classified asFB3 type according to theguideline classification systembased on the UCS and ITS values.The mechanistic-empirical designmodel developed for the guidelineswas based on this material andtherefore requires validation.
Purpose of Testing on TR11/1
The purpose of testing of G2(crushed stone) material treatedwith foamed bitumen on TR11/1 isto calibrate the empiricalcomponents of the general designmodel for high quality materialthat would be used for the designof high traffic classes (ES3 -ES10).
97
Further testing offoamed bitumentreated materialson TR11/1 nearCape Town
Elzbieta SadzikMaterials Chief Engineer
Gautrans
Mervyn HendersonChief Engineer Materials Design
PAWC
The purpose of testing G2 material with foamed bitumen is tocalibrate the empirical components of the general design model.
The test results will be used torevise the Interim TechnicalGuideline TG2.
Pavement Structure on TR11/1
The pavement structure beforerecycling consisted of:
• 19mm Cape Seal• 200 mm G2 base (crushed
hornfels)• 150 mm G5 subbase
(crushed hornfels)• 400 mm selected layer
(natural sand)• Subgrade - sandy material
The pavement structure afterrecycling consists of:
• 18mm NovaChipTM on 35 mmasphalt;
• 200 mm G2 and 50 mm G5recycled with 1% cement and2.3% foamed bitumen;
• 100 mm G5 subbase;• 400mm selected layer
(natural sand); and• Subgrade - sandy material.
HVS Testing
The HVS testing on TR11/1 startedon 18 September 2002. Thetesting consisted of two phases.Phase 1 being 500 000 repetitionsof high wheel loads (80 kN to 100kN) to establish the basicbehaviour of the pavement, andPhase 2 to characterise thepavement behaviour under astandard wheel load of 40 kN.The planned completion date forthe HVS testing is the end ofJanuary 2003.
Pavement response to the appliedloads is measured by:
• Surface deflectometer;• Multi-depth deflectometer;• Laser profilometer; and• Straight edge.
Additional pavement datacollected during testing includesthe road surface temperature,moisture contents and surfacedefects.
At the end of Phase 1NovaChipTM surfacing was foundto compress under traffic, from18 mm thick layer to 15 mm,although it did remain quitestable. No crushing was visible.The multi-depth deflectometershowed that the permanentdeformation took place mainlyin the subbase layer.
Laboratory Testing
Objectives of the laboratorytesting were to:
• Quantify material behaviour;
98
Visual evaluation of the HVS test section(photograph by F. Long)
• Investigate the effects ofinteraction between cementand foamed bitumen in termsof material flexibility andstrength; and
• Obtain data for use instructural design models.
The following tests will beperformed:
• Standard materials tests;• UCS, ITS, CBR;• Flexural beam tests;• Fatigue tests;• Static and dynamic triaxial
tests;• Permeability and erodibility
tests;• Shrinkage; and• Microscope pictures.
Five tons of untreated (beforerecycling) material was removedfrom the road and transported toCSIR laboratory in Pretoria for
testing. It is expected that thelaboratory tests will be completedby July 2003.
Funding of projects
The first project on emulsion andfoamed bitumen treated materialscarried out in Gauteng on roadP243/1 was funded by theGauteng Department of PublicTransport, Roads and Works(Gautrans). Funds from Sabitahelped to develop the InterimTechnical Guideline TG2.
Further testing of foamed bitumentreated materials on TR11/1 nearCape Town was possible due tothe partnership of three roadauthorities, namely: Gautrans,SANRAL and the ProvincialAdministration Western Cape(PAWC). �
99
Participants of the HVS technical meeting: from left Johan Otte (PAWC), RonaldoLorio (UWP), Pikkie Genade (Consultant), Giliomee Matthee (PAWC), Fenella
Long (CSIR), Bruce Morton (CSIR), Mervyn Henderson (PAWC), Prof. Kim Jenkins(SANRAL Chair US), Hechter Theyse (CSIR), Elzbieta Sadzik (Gautrans),
Llewellyn Truter (PAWC).
Colas Ad
Introduction
Roughly 100 million litres ofbituminous binders aresprayed every year in South
Africa. The spraying of thesebinders is done by an estimated75 calibrated distributors, mostlyBearcat, Etnyre, Rosco or Acmardesign spray bar systems.
In recent years most of theattention and focus has been onthe development of binderspecifications with the emphasison a move from empirical to moreperformance related properties,
with little or no attention given tothe application side. We have alsoseen a significant shift fromspraying only emulsion andcutback bitumens to hot binders.With the increase in trafficvolumes, a sharp rise in demandfor and usage of more viscousmodified binders, equating to
almost 40% of all sprayed bindersused in seals, has been noted.
Issues facing binderdistributors
The above developments havemade it imperative that theblacktop industry acknowledgethat it is working with someoutdated specifications anddocumentation, which militatesagainst good engineering practice,when it comes to binderdistributors. At a meeting of the
Road PavementForum (RPF) inMay 2002 themain issuescausing problemsfor the industrywere identifiedas:
• Variousmethods andcriteria usedto determineon-site
transverse distribution of thespray bar;
• Varying periods of validity forbinder distributor calibrationcertificates;
• Unrealistic tolerances for thebinder spray rate; and
• Lack of agreed protocols forflushing and testing of spray
101
Update on the RPF’s task team onbinderdistributors
Trevor DistinChairman
RPF Task Team on Binder Distributers
Figure 1: Typical chip and spray sealing applicationusing PMB binder
bars on-site with respect tothe environment and workersafety.
RPF Binder Distributor TaskTeam formed
A resolution was passed by theRPF to form a task team with thefollowing terms of reference:
• Review the compliancecriteria for transversedistribution and develop arational and practical methodfor conducting on-sitetesting;
• Investigate the need for andrelevance of calibrationcertificates;
• Investigate spray tolerancesfor various binders; and
• Develop a protocol forflushing and testing spraybars on-site in line with HSErequirements.
A task team was formed withequal representation from allmajor sectors and across thegeographical spectrum. The taskteam is chaired by Trevor Distinand has the followingmembership;
Clients: Theuns Lewis, WallyBennett and Dennis RossmannConsultants: Wouter Schreuder,Russel Clayton and Douglas JuddContractors: Gerry Reitsma,Philip Kuun and Charlie BacklundApplicators: Denzil Sadler, KevinSpence and Kobus Louw
Desired outcomes
At the first meeting it was agreedthat the desired outcome of thedeliverables should be: To ensurethat the binder is sprayed at thecorrect rate, within acceptabletransverse distribution limits,within acceptable tolerance rates,and handled in a responsiblemanner with respect to workerhealth, safety and theenvironment. The task team alsoagreed that the industry shouldstrive to become self-regulating.However there needed to becertain controls in place, in whichcase the TMH 2 document shouldbe revised and published as a newstandard.
Work groups were established toaddress the most pressing issuesand their progress will be brieflydiscussed.
On-site measurement oftransverse distribution
Different methods are currently inpractice in South Africa todetermine on-site distribution ofbinder distributors. The mostcommonly known method is the‘bakkie’ (container) test.
This test consists of spraying theproduct for 15 seconds directlyinto a container. The containersare arranged so that there arethree nozzles per ‘bakkie’ and thenet mass of all the 14 containersis compared. While there aredifferent acceptance criteria, the
102
The industry should strive to become self-regulating
most common method is tocalculate the mean mass of all 14results and any value with avariance of more than 5 % will beconsidered unacceptable.
Appendix J of TRH 3 (1998edition) specifies that thetransverse distribution must bechecked by placing four troughs,one under each extension and twounder the main bar, and the massof binder sprayedmust not vary bymore than 5%.
The problem withthese methods isthat they do notcorrelate with thecriteria specifiedin TMH 2 (1979edition) for fix pitcalibration. Inthe latter test, oilwith a givenviscosity is
sprayed at a temperatureof 40°C into 50 mm widetrays placed at groundlevel. The transversedistribution is determinedby comparing thevolumetric quantitiesmeasured in all 81 slottedtrays. One of the criteria isthat 5% (ie four of thetrays) may not exceed18% of the mean value. Itis quite common to findthat the latter requirementwill be met, but that thesame sprayer will generallyfail the ‘bakkie’ test. As aninterim measure we arelooking at computing therecent values from thefixed pit test facilities with
the view of arriving at morerealistic acceptance levels. Thiswill bring the limits for both testsmore in line with one other.
Based on common practice inmany overseas countries, theworking group will be developing asimple and practical on-sitemethod of measuring transversedistribution using a suitableabsorbent material which is placed
103
Nozzle
Triple overlay
Double overlay
Single overlay
Poor coverage
Poor coverage
Good coverage
Spraybar
Figure A
Figure B
Figure 2: Typical ‘Bakkie’ tests results
trough number
%deviation
-15
-10
-5
0
5
10
1 2 3 4 5 6 7 8 9 10 11 12 13 14
Figure 3: The effect of the spray overlap on the transversedistribution
on the road surface. The net massof binder sprayed on the sectionsof absorbent pads will bemeasured and compared with anacceptable criteria.
Calibration of sprayers
There are only three fixed pitfacilities in South Africa - inPretoria, Pietermaritzburg and PortElizabeth - which currently issuecalibration certificates for binderdistributors. With the validityperiod of these certificates varyingfrom 3 to 12 months (dependingon the client) the cost of havingsay a Cape Town based distributorre-certified goes far beyond justthe cost of the test. One has onlyto take into account the timerelated costs associated withpreparation and travelling torealise the futility of the exercisewhen the likelihood is that thedistributor will fail the ‘bakkie’ teston return to the work site.
There is a strong consensus tostandardise the validity period andinvestigate some form ofself-regulation with theintroduction of ‘bakkie’ tests at theapplicator’s depot.
Matrix of spray rate tolerances
COLTO currently stipulates atolerance of +0.06 litre/m2 of netcold binder and +5% for bitumenrubber from the design spray rate.There are various factors whichinfluence the ability of thedistributor to comply with theserequirements, inter alia accuracyof the dip stick, the volume ofbinder sprayed, expansion of the
dip stick at high temperature,expansion/contraction of theproduct, and the viscous nature ofmodified binders.
Another working group isdeveloping a matrix for binderspray rates according to thefollowing criteria:
• Type of binder, namelyNewtonian vis-à-visnon-Newtonian;
• Types of application, namelysingle/double seal versussand seals and primes; and
• Traffic levels from residentialto freeways.
It was nevertheless agreed thatacceptance criteria should bebased on the minimum lot size of4,000 litres and expressed as apercentage at the spraytemperature.
Safety and the environment
A guideline document has beendrafted on best house keepingpractices covering the legalresponsibilities of the suppliersand applicators with respect to:
• Transportation of binders insprayers;
• Temporary storage of binderson-site; and
• Application of binders on-site.
This information, along with bestglobal practice and the legislationon waste disposal, will be incor-porated into an updated version ofSabita’s Bitumen Safety Handbook(Manual 8).
104
Conclusion
Whilst some good progress hasbeen made in certain areas we stillhave a long way to go beforeachieving acceptance by all partieson these issues. However therehas been open sharing of concernsby all participants, and we hope toexpand the membership of theworking groups to involve more
client bodies to broaden theirrepresentation. There is, however,still some concern over theupdating of the COLTO and TRHdocuments, wherein the workingsof the task team will ultimately bepublished. This issue is currentlybeing addressed by the RoadPavements Forum (RPF). �
105
106
107
BestPractice
4
108
Millions of Rands worth ofdecisions are maderegularly on the results
from our road industrylaboratories. However, the lack ofconsistency and reproducibility oflaboratory test results has led toan increasing lack of confidence inthe results by the industry, and aninsistence by major client bodiessuch as SANRAL, PAWC andGautrans that, where practical,such testing be carried out byaccredited laboratories.
While the accreditation processhas been accepted by some of thelarger commercial laboratories andthe client laboratories, the majorchallenge to the industry will be toensure some sort of quality controlover the consistency of resultsemanating from the increasingnumber of small, mainly site,laboratories that are nowundertaking materials testing.This situation is already receivingattention by the South AfricanNational Accreditation Service(SANAS).
Laboratory accreditation is linkedto a diversity of influences such asmanagement, equipmentcalibration and personnel skills so
that laboratories can “assure theaccurate, reliable and promptreporting of test results andassure the adequacy andcompetency of the laboratorystaff”, as required by SANAS.
The accreditation process alsorequires laboratories to be part ofa laboratory proficiency scheme.However, no functional laboratoryproficiency scheme/s in line withISO 043 exist to assess whethersuch tests are being performed
properly, and that the accuracy ofthe results are within the expectedprecision limits for the tests.
In an effort to tackle theseproblems the Road PavementsForum (RPF), in November 2001,resolved that the Asphalt Academy(AsAc) convene a task group toinvestigate the problems and giverecommendations on possiblesolutions. The role of the TaskGroup was to “coordinate theaccreditation, verification andproficiency activities of materialstesting laboratories with theultimate aim of improvingconfidence levels in test resultsemanating from laboratories”.
109
Laboratory proficiency scheme amust for SAroadsindustry.
Les SampsonConvenor
RPF Task Team onLaboratory Accreditation
The major challenge will be to ensure some sort of quality controlover the consistency of results emanating from laboratories.
A comparison of laboratoryprocedures and results hadrevealed a variety of factors whichwere causing concern. Theseincluded undefined andunstructured operations, poorcalibration of equipment andnon-compliance with standard testmethods.
By contrast, a properly formulatedlaboratory Proficiency Schemewould provide quality assuranceaccording to national andinternational standards, wouldinstall well designed andstructured procedures, andensure that theseprocedures arecoordinated bycomprehensive guidelinesand manuals — ultimatelyincreasing the confidencein the test resultsemanating from thevarious laboratories.
The Task Groupestablished the followingProficiency Scheme actionplan:
• establishment of asub-committee toinvestigate appropriateproficiency schemes;
• create a prioritisationframework for test methodsrequired to undergoproficiency testing;
• prioritise test methods forproficiency testing;
• develop guidelines on aproficiency scheme for theroad sector in line withISO 43;
• establish a coordinatingstructure;
• identify potential serviceproviders to manage thescheme; and
• identify and motivate fundingto implement the scheme.
At the RPF meeting in November2002, the Task Grouprecommended that:
• A National ProficiencyScheme, as shown in Figure 1below, be established for theroad sector in support of theaccreditation process;
• This scheme should becontrolled by a NationalCoordinating Body to benamed the NationalProficiency AssessmentService for Roads (NPASR);and
• The Proficiency scheme wouldbe run by independentservice provider(s) who willanswer and report to NPASR.
Subsequent to the meeting, theTask Group was requested toconvene a meeting of interested
110
Laboratory 1 Laboratory 2 Laboratory n
SANAS(Specialist testing
committee)
National Coordinating
Body
(NPASR)
Proficiency Scheme ManagementSampling plans and procedures
Validation of test methodsStatistical evaluation of results
Reporting and certification
Accredited reference
laboratories
MTC
Figure 1. Proposed structure of a NationalProficiency Scheme
parties to evaluate the fundingimplications associated withestablishing a laboratoryProficiency Scheme, and to set upmechanisms and procedures tosecure that funding.
While it is envisaged that theProficiency Scheme wouldultimately be self-supportingthrough the participating
laboratories (each test will have aproficiency requirement, which willbe charged for), upfront fundingwill be required to set up theprocedures, documentation andmanagement structures -including the establishment of anational database.
Meetings with potential fundershave been scheduled for 2003. �
111
Introduction
The South African BitumenAssociation (Sabita) hasdeveloped guidelines on
health, safety and environmentalconservation as related to the useof bitumen and related products1.
However, although the approachtaken in the document is excellentand in line with best South Africanand international practice, thesection on the disposal of bitumenwaste products does not adequat-ely cover current South Africanrequirements.
In terms of the EnvironmentalConservation Act, all wastes mustbe classified and disposed of in amanner that complies with theMinimum Requirementsdocuments published by theDepartment of Water Affairs andForestry, (DWAF) 19983-5. Of
particular importance are theMinimum Requirements for theHandling, Classification andDisposal of Hazardous Waste3,which dictate the procedures thatmust be followed for the classi-fication and assessment of theenvironmental impact of wastematerials.
As the Department of WaterAffairs and Forestry is planning torevise current documents in thenear future, an excellentopportunity to revise the
classification of bitumen hasbecome available. This projecttherefore evaluates theclassification and disposaloptions for bitumen, focusing ondeclassification of bitumen as ahazardous material in line withEuropean classification.
112
Bitumen waste management:
Evaluation of options forclassification anddisposal
Mannie LevinSenior Geohydrologist
Africon
PROJECT TEAM
Dr M Levin - AfriconDr W van Niekerk - InfotoxDr D Baldwin - Environmental & Chemical Consultants
All wastes must be classified and disposed in a manner thatcomplies with the minimum requirements of the DWAF.
Types of bitumen and bitumenderivatives
Bitumen products are complexcombinations of petroleumformulations, and are classifiedunder different names.
Bitumen is a black or dark brownsolid or semi-solid thermo-plasticmaterial possessing waterproofingand adhesive properties. It isessentially non-volatile at ambienttemperatures, and has low watersolubility. Bitumen is manufac-tured from crude petroleum oiland is a complex combination ofhigher molecular weight organiccompounds with a high carbon tohydrogen ratio, containing arelatively high proportion ofhydrocarbons with carbonnumbers greater than C25. Itmay also contain trace amounts ofmetals such as nickel, iron andvanadium.
Bitumen is very different from coaltars and pitches, which areobtained by the destructivedistillation of coals, or mixtures ofthese with bitumen or bitumenderivatives. Chemically, coal tarmaterials are composed mainly ofhighly condensed-ring aromatichydrocarbons.
Bitumen, on the other hand,contains a much higher proportionof relatively high molecular weightparaffinic and naphthenichydrocarbons and theirderivatives. For example, theconcentration of polynucleararomatic hydrocarbons (PAHs) incoal tar pitches is several orders of
magnitude higher than thatdetermined in bitumen.The term bitumen is also used fornatural bitumens that can occur asnatural deposits or as a com-ponent of naturally occurringasphalt, in which it is associatedwith mineral matter. Althoughnatural bitumen may be similar inphysical properties to processedbitumen, it is different in chemicalcomposition.
Asphalt refers to a mixture ofbitumen (as defined above) withmineral matter such as stone,sand or other filler material.However, in the USA, asphaltrefers to bitumen as definedabove.
Three main types of bitumen:
• Penetration grades areusually produced from crudepetroleum oil atmosphericdistillation residues by usingfurther processing such asvacuum distillation, thermalconversion, partial oxidation,or solvent precipitation. Acombination of theseprocesses can be used tomake different grades, whichare normally classified bypenetration valuespecifications. Penetrationgrade bitumens areprincipally used for roadsurfacing and in roofing.
• Hard bitumens aremanufactured usingprocesses similar to thoseapplicable to penetrationgrades, but have lowerpenetration values and highersoftening points, i.e. they are
113
harder and more brittle. Themain use of hard bitumen isin the manufacture ofbitumen paints and enamels.
• Oxidised bitumens areproduced by passing airthrough a bitumen feedstockunder controlled conditions,which produces highersoftening point bitumen withreduced susceptibility tochange under the influence oftemperature, and a greaterresistance to imposed
stresses. Applications includeuse in roofing materials,waterproof papers, electricalcomponents and many otherbuilding and industrialproducts. Classification isnormally by both penetrationvalue and softening pointspecifications.
There are four basic types ofbitumen derivatives:
• Cutback bitumens aremixtures of bitumen withvolatile petroleum diluentssuch as white spirit andkerosene to render themmore fluid for ease ofhandling and application.Depending on the level andvolatility of the diluents, theoriginal properties of thebitumen may be partly orcompletely recovered byevaporation after applicationof the cutback. Cutbacks aresometimes heated to
temperatures of up to 175°Cfor handling and application.Cutback grades are mainlyused in road surfacedressing.
• Fluxed bitumens aremixtures of bitumen withfluxes to make products thatare easier to use in certainapplications. Typical fluxesinclude high boiling pointpetroleum products such asindustrial process oils, orheavy distillates, typicallywith initial boiling points
above 350°C. There is onlylimited evaporation of theflux after applications, andfluxed bitumens have limitedapplications.
• Bitumen emulsions are finedispersions of bitumen inwater, normally manufac-tured from penetrationgrades. Some emulsionsmay contain fluxing agentsand/or volatile diluents eitheradded during production orpreviously blended. Thebitumen solids content of anemulsion varies between 40and 80 per cent, andapplication temperaturesrange from ambient to 90°C.Three types exist, defined bythe type of electrical chargeimparted by the stabilisingagent (emulsifier or soapsolution) to the bitumenparticles, i.e. anionic, cationicand nonionic. Cationicemulsions are used mostfrequently, and in many parts
114
Further projects on the declassification of bitumen emulsions andcutback bitumens are envisaged.
of the world they are morewidely used than cutbackbitumens. Some specialemulsions may bemanufactured from modifiedbitumens, or have polymersadded in the form of a latex.
• Modified bitumens arebitumens in which fluidmechanical properties havebeen substantially changedby the addition of a physicalor chemical agent. They aremainly used in roadconstruction, roofing andwaterproofing, sometimes atelevated temperatures (up to230°C).
The present project focuses onlyon penetration grade bitumens,but future projects on thedeclassification of bitumenemulsions and cutback bitumensare envisaged.
Methodology
Selection of bitumen samples
While many bitumen products areavailable in South Africa, it wasdecided to do an initial study on abitumen sample that could beconsidered to be typical of thoseproduced in South Africa. Theobjective was to obtain anunderstanding of the behaviour ofthis material before other bitumenproducts were classified andevaluated according to therequirements.
Sasol Oil was asked to supply abitumen sample and they providedan 80/100-penetration gradebitumen produced by Natref.
Natref produces 80% straight run80/100-pen grade bitumen and20% straight run 150/200-pengrade bitumen: other penetrationgrades, namely 60/70 and 40/50,are produced from 80/100-pengrade bitumen.
As part of the second phase study,representative samples ofpenetration grade bitumens wereobtained from the other threerefineries in South Africa, plus asample of a used road bitumen.This was done in order to comparethe bitumens produced by thedifferent refineries and to assessthe impact of ageing andweathering on a bitumen that hasbeen used in its most commonapplication as a road surfacingmaterial.
It should be noted that smalldifferences in the chemicalcomposition are expected, whenbitumens produced at differentrefineries in South Africa arecompared: the differences inchemical composition are largelydue to the different crude oilsused in these refineries.
Analysis required
The bitumen samples weresubmitted to Test House, a SABSaffiliated company that was askedto undertake the US EPA ToxicityCharacteristic Leaching Procedure(TCLP), followed by analysis of theleachate for a standard list of 18heavy metals.
Note that the TCLP was chosenrather than the South African AcidRain Leaching Procedure (ARLP),
115
as the bitumen is an organicmaterial and it will be disposed toco-disposal sites, i.e. ones thatcontain general (household andcommercial) waste.
Portions of the samples were alsoforwarded to CSIR Bio/Chemtek,Modderfontein, Johannesburg, fororganic analysis. The sampleswere analysed for volatile andsemi-volatile organic compoundsboth in the bitumen samples andthe TCLP extracts produced byTest House: the bitumens werealso analysed for PolycyclicAromatic Hydrogens (PAHs) usinga High Performance Liquid
Chromatography (HPLC) method.
Classification of PenetrationGrade Bitumen
Primary ClassificationAccording to SABS 0228
SABS Code 0228, which iseffectively the IMDG (InternationalMaritime Dangerous Goods) Code,classifies bitumen (UN # 1999) asa flammable liquid, i.e. class 3,which is defined as:
“Liquids or mixtures of liquids orliquids that contain solids insolution or in suspension (e.g.paints, lacquers, but not includingsubstances that, on account oftheir other dangerouscharacteristics, have beenincluded in other classes) that giveoff a flammable vapour at orbelow 60.5°C, closed cup(corresponds to 65.6°C, open
cup). This class also includesliquids that emit flammablevapours at or below the maximumtransportation temperature.”
Bitumens can belong to dangergroup II, i.e. flash point < 23°C orgroup III with a flash point> 23°C but < 60.5°C. However,note that penetration gradebitumens are normally handledand transported at 150°C-170°C,where the potential risk associatedwith the flammability hazardouscharacteristic is naturally higher.Penetration grade bitumengenerally has a melting pointbetween 38 °C and 56°C, and will
thus, for disposal purposes, be a
solid at room temperature. Theflash point of penetration gradebitumen is given as 2300C .
Thus, the only potentiallyhazardous characteristic is that oftoxicity in terms of inorganic ororganic compounds. The bitumensamples were evaluated for thetoxicity characteristic according tothe procedures in the MinimumRequirements.
Inorganic Species
TCLP extracts were performed on18 elements of concern. The pH ofthe leach solution used in theTCLP is 4.93 +0.05 and, afterextraction of the penetrationgrade bitumens, the laboratoryrecorded the final pH values of allfour leach solutions as 4.9. Thus,as expected, these organic
116
The only potentially hazardous characteristic is that of toxicity interms of inorganic or organic compounds
materials do not have anysignificant alkalinity and, whenextracted at a low pH and underexhaustive conditions, i.e. for 20hours, the leaching of tracequantities of heavy metals, ifpresent, must be expected.
Note that water extraction testshave shown that As, Cd, Cr, Cu,Hg, Pb, Ni and Zn did not leachfrom bitumen samples, even atvery low detection limits8.
Organic Results
A wide range of chlorinated andnon-chlorinated aliphatic andaromatic volatile organic com-pounds were targeted, togetherwith semi-volatile compounds.Bitumens are complex mixtures ofrelatively high molecular weightcompounds that typically contain82-85% combined C; 12-15% H;2-8% S; 0-3% N and 0-2% O1.The organic compounds inbitumen include alkanes,cycloalkanes, aromatics, heteromolecules containing S, N and/orO, plus small amounts of poly-cyclic aromatic hydrocarbons1.
The following were noted: Thepenetration grade bitumenscontain small, but significant,amounts of volatile aromatichydrocarbons, notably the BETXcompounds (benzene, ethyl-benzene, toluene and xylenes)plus trimethylbenzenes. Onesample contained low amounts ofbenzene, which is a recognisedhuman carcinogen.
However, as its concentration isless than 1% (10,000 ppm), thecarcinogenicity is not taken into
account in the MinimumRequirements for the Handling,Classification and Disposal ofHazardous Waste and it,therefore, classifies as a highhazard, HG2 rather than anextreme hazard.
Environmental RiskAssessment
The secondary environmental riskassessment includes an evaluationof waste and site specific issues,such as environmental fate, loador dose to the landfill site, type oflandfill site, etc6. As previouslymentioned the next edition (3rd)of the Minimum Requirements forthe Handling, Classification andDisposal of Hazardous Waste isexpected to give guidelines andMinimum Requirements for theevaluation of these issues.However, as the development ofthe new document will onlycommence in 2003, the approachthat will be used in the documentis not certain.
Nevertheless, in this section of thereport, some of the key issuesthat mitigate the impact ofbitumen, when it is co-disposed toan HH, Hh or G landfill, arediscussed. The issues selected arethose that are considered by theconsulting team as the most likelyissues to be in the reviseddocument:
Environmental Fate of SelectedSpecies
In this section, the possibleenvironmental fate of each of thespecies that are present in andobserved to extract from the
117
bitumen samples using the TCLP isevaluated. Note that thediscussion is limited to the fate ofthe species within the landfillenvironment, and the environ-mental fate, if a species managesto escape from the site, i.e. intoground and surface waterresources, is not considered.
Load or Dose Disposed toLandfill
Although a waste material leachesa hazardous species, it could stillbe disposed to a general wastesite, depending on the amount ofwaste that requires disposal, theleachable concentration of thehazardous species and the size of
the landfill.
Disposal of the BitumenWastes
As indicated above, theDepartment of Water Affairs andForestry normally requires adelisted waste to be disposed toan H or alternatively a GMB+ orGLB+ landfill, i.e. one that isclassified as medium or large andis equipped with a leachatemanagement system. However,there is a paucity of such landfillsin South Africa. They are fairlycommon in the coastal or waterexcess areas, simply becauseleachate will be generated and,
therefore, a leachate managementsystem must be in place. In thewater deficit areas, i.e. in most ofSouth Africa, the sites that areavailable are normally permittedas GB- sites. Very few GMB+ orGLB+ landfills are available andthese tend to be in large urbanareas such as the East Rand,where the co-disposal of liquids isrequired. Thus, the requirementto dispose in H, GMB+ or GLB+landfills would require bitumenwaste to be transported over longdistances with corresponding veryhigh costs.
In some instances the Departmentof Water Affairs and Forestry hasrelaxed the above requirement
and allowed some wastes to be
disposed of in permitted and welloperated GMB- or GLB- landfills.This has been allowed where it canbe demonstrated that the wastewill not contribute to thegeneration of leachate, i.e. iseffectively dry, and the quantitiesgenerated are small.The bitumen wastes discussed inthis report could fall in thiscategory. It is therefore proposedthat application be made, on thebasis of the results presented inthis report, for general permissionto dispose of small amounts atGMB- or GLB- landfills, where anH, GMB+ or GLB+ landfill is not
118
The penetration grade bitumens and used road bitumen can bedelisted for disposal to GMB- or GLB- landfills.
available within a reasonabledistance.Conclusions
It is concluded that:
• As no organic compoundsleach from the penetrationgrade bitumen and the usedroad bitumen samples, it isthe leachable heavy metals inasphalt that determine thehazard rating. Samples closeto the detection limits arere-analysed to ensurecompliance.
• The penetration gradebitumens and the used roadbitumen can be delisted fordisposal to GMB+ or GLB+landfills, according to thecurrent requirements of theDepartment of Water Affairsand Forestry. It is proposedthat once the current studyhas been completed,application be made to theDepartment for permission todispose of small amounts of
the wastes to GMB- or GLB-landfills.
• Additional work that needs tobe undertaken should includethe other types of bitumensuch as bitumen emulsionsand cutback bitumens. �
References
1 Health, Safety and Environmental Guidelines forBitumen and Coal Tar Products; Revised edition July1998, Sabita.2 Leith, Jacqueline, “An Incident that may Reforman Industry”, Resource, 3(2), 11-13 (2001)3 Department of Water Affairs and Forestry,Minimum Requirements for the Classification,Handling andDisposal of Hazardous Waste, 2nd edition, 1998.4 Department of Water Affairs and Forestry,Minimum Requirements for Waste Disposal byLandfill, 2nd edition, 1998.5 Department of Water Affairs and Forestry,Minimum Requirements for Monitoring at WasteManagement Facilities, 2nd edition, 19986 Baldwin D A, “Waste Classification and Site RiskAssessment”, 3rd Conference on EnvironmentalEngineering", SAICE, Kwa Maritane, May 19997 Department of Environment Affairs and Tourismand the Department of Water Affairs and Forestry,“National Waste Management Strategy”, Version C,PMG 130/PSC69, September 19998 Bowen C, de Groot P and Brandt C A, Health,Safety and the Environment - Leaching of PAH’sfrom Bitumen, Proceedings 2nd Eurasphalt andEurobitume Congress Barcelona, 2000, Book II-754to 761
119
In the mid 1980’s the pre-fabricated, bitumen-rubberbound road patch was
developed and refined as aproduct to deal with routine roadmaintenance projects whereconventional, brittle asphaltproducts were inappropriate. Thebitumen-rubber used as the roadpatch binder has the flexibility toabsorb both surface andfoundation movements withoutcracking, and the road patch hasbeen used with considerablesuccess. This mechanical propertyadded to the prefabricated formatof the road patch resulted in asuperior maintenance solutionwith distinct economic benefits.
Application developments inthe 1990s
During the 1990’s road authoritiesplaced more emphasis on theimplementation of traffic calmingand safety projects using devicesthat were purpose-designed forthe specific sites.
Rumble Strips were easilyfashioned from prefabricated roadpatches by pre-cutting the patches
into the desired strip width. Thesestrips provide effective vibratoryand audible warnings to motoristsof an impending change in theroad conditions.
A further development was that ofrumble humps consisting of two ormore layers of varying widths ofroad patch. They are installed inareas where a structure isrequired to force motorists tocomply with the posted speedlimit. Rumble humps are moresevere than rumble strips, but lesssevere than conventional speedhumps. The ability to havenumerous combinations of bothwidth and height by varying the
aggregate size and the number oflayers gives the authoritiesunlimited variations of rumblehump configurations when usingroad patches.
Prefabricated crack sealing stripswere developed from the roadpatch to prevent activebase-caused cracking reflectingthrough overlays or reseals. Againcold application without capitalexpenditure has proved a boon toroad authorities.
120
Development of theprefabricated bitumenrubber boundroad patch
Michael ChurchProject Engineer
AJ Broom Road Products
These strips provide effective vibratory and audible warnings tomotorists of an impending change in the road conditions.
Edge-break repairs could easily beundertaken using the roadpatches. This material, beingsurface installed, precludes theneed to square cut the edge andset down the shoulder compactingmaterial as is necessary whenusing conventional methods.
Application developments inthe 2000s
Further emphasis was placed onroad safety in this period and twosignificant developments wereintroduced.
Firstly mountable traffic circlesprefabricated in bitumen-rubberbound road patches weredeveloped. This system hasadvantages over concrete or
asphalt traffic circles, such as theavoidance of any need to cut akey into the existing surface toavoid feather edging, and therebeing no curing period with roadpatches.
Secondly centre line and shoulderline lane diverters were developedto prevent vehicles straying acrossthe centre line. This system hashelped to reduce collisions, andhas been equally successful inpreventing vehicle run-offs wheninstalled as shoulder line lanediverters.
Coloured surfacing is also nowavailable in a prefabricated roadpatch format for easy demarcationof lanes and barriers, and on roadsigns and corporate logos. �
121
AJ Broom Ad
1. Introduction
Enrichment or rejuvenatorsprays are verycost-effective remedial
treatments for extending the lifeof an oxidised blacktop surfaceshowing signs of stone loss and/orsurface cracking. While the use ofdiluted emulsion as an enrichmentspray is a fairly common practicein South Africa, many roadengineers are sceptical aboutso-called rejuvenation sprays andtheir appropriateness, given therange of other products available.
The purpose of this paper is tocapture best practice in the use ofboth diluted emulsions as enrich-
ment sprays, and a typical pro-prietary product as a rejuvenatorspray.
2. Functions of enrichment/rejuvenator sprays
Diluted emulsions
The main function of a dilutedbitumen emulsion is to retardstone loss by adding binder, andto partly enrich the binder in ageddry stone seals. Dilution of
bitumen emulsion with waterlowers the viscosity, permittingeasier penetration into the surface
123
Surface enrichment sprays:
A cost-effective solutionfor preventativemaintenance Trevor Distin
Marketing ManagerColas SA
Figure 1: Dilute emulsions for enrichment
Many road engineers are sceptical about so-called rejuvenationsprays
voids, as shown in Figure 1. Thewater evaporates leaving aresidual deposit of bitumen toimprove stone retention. Excessbitumen deposited on the stone isridden off with traffic.
This is somewhat different fromapplying a diluted emulsion as acover spray to a newly constructedsingle or double seal to preventaggregate loss. The purpose of thebinder is to create a bond acrossthe top of the aggregate as can beseen in Figure 2.
While a product such as this alsoadds new bitumen to thesurfacing, it has the added benefitof rejuvenating the aged bitumen.This is achieved by means of thecutter medium, which also helpsthe rejuvenator penetrate theexisting surface by up to 10 mm,depending on the type of surface.Other benefits are:
• it helps close up hairlinecracks over time undertraffic;
• assists in the prevention ofstone loss;
• improves surfaceimpermeability
3. Types of enrichment/rejuvenator sprays
3.1 Dilute emulsions
The following grades of bitumenemulsion can be diluted with waterand used for enrichment sprays,also known as fogsprays:
• Anionic or Cationic Stablemix60%;
• Unfluxed Cationic Spray 60,65 or 70%;
• Unfluxed Cationic Spray 65 or70% modified with SBR latex(Rubspray); and
• Latex Modified CationicMicrosurfacing Emulsions.
3.2 MSP 3TM
This product is an invertedemulsion manufactured from abinder containing bitumen,aromatic oil and a cutbackmedium. It is designed as asurface enrichment orrejuvenating agent, and oncesprayed, penetrates into dried andaged bituminous surfaces,rejuvenating the binder andextending the period beforeresurfacing becomes necessary.
124
Figure 2: Dilute emulsion for cover sprays
When more binder is required inthe surfacing it is recommendedthat bitumen emulsions be used.When the oxidised binder needs tobe rejuvenated, inverted cutbackemulsion is more suitable.Unfluxed latex modified emulsionscan be applied on surfaces that
show early signs of surfacecracking, the precursor to thedevelopment of crocodile cracking.This emulsion will set rapidly andsurfaces can thus be opened fairlyquickly to traffic.
4. Performance
The factors mostly affecting theperformance of emulsions as anenrichment spray are:
4.1 Type of emulsion to usefor enrichment spray
Cationic spray grades will tend tobreak quicker than anionic andcationic stablemix emulsions,which are more stable. Thus withspray grade emulsions the binderwill tend to be deposited on top of
the stone chips, whereasstablemix emulsions will tend toflow into the voids more easily.
Cationic grade emulsions willrender improved binder/aggregateadhesion due to the chemicalreaction which takes placebetween the positively chargedbitumen droplets in the emulsion(and latex if used) and the freenegatively charged ions of theaggregate.
4.2 Weather conditions(dilute emulsion)
The prevailing weather conditionswill affect the ‘breaking’ of adiluted emulsion. In the case ofcolder weather and in shadedareas, the lower temperatureretards the breaking action of theemulsion, and in this case quickerbreaking cationic spray gradesshould be used.
During hot weather, latex modifiedemulsion will tend to form a skinwhich could create a falseperception that the emulsion hasbroken. When this phenomenonoccurs, total breaking of theemulsion can be delayed forseveral hours. The emulsion mustbe checked by scratching with aknife to ensure that it is uniformlyblack under the skin.
In hot weather, the residual binderfilm tends to become tacky,resulting in pick-up on the tyres.When the expected road surfacetemperature is above 50°C, ahigher softening point binder suchas 60/70 penetration basebitumen must be considered.
125
Typical application of rejuvenatorspray
As a general guideline thefollowing closure times should beobserved after spraying, based onprevailing weather conditions:
• hot, windy day: 2 hours• overcast, cool day: 4 hours
If the road is opened too early,the fog spray will be picked up. Ifit becomes necessary to open totraffic, use coarse sand to blind inorder to reduce the tackiness.
Proprietary inverted cutbackemulsions
There are some time and dryingconstraints to be considered whenselecting candidate pavements fortreatment with inverted cutbackemulsions, particularly in coolclimates.
However this should not be adeterrent to their use, because thecost of any traffic accommodationis far less than the cost ofalternative treatments. Invertedcutback emulsion is ideal for hot,dry climates. In cool climates, thedrying time will be extended, andtraffic control on roads could bedifficult, although this will be lessof a problem on areas such asairport secondary runways.
When applied on coarse surfacessuch as chip seals, traffic can beallowed onto the surface withinfour hours, while the drying/penetration time on dense asphaltsurfaces could be up to 36 hours.
This limits the application to roadsthat:
• can be closed for a period;• roads with several lanes, of
which one can be closed;• where the traffic can be
diverted;• airport pavements.• very light traffic, two-lane
roads, where single laneoperation can be put in placefor several kilometres. Inpractice this might meanexecuting the work over aweekend.
4.3 Presence of cutter(dilute emulsions)
The presence of cutter in emulsionis not desirable when used as anenrichment spray, because theresidual binder tends to remaintacky after breaking. It must alsobe noted that all standard spraygrades of emulsion are formulatedwith between 2% to a maximumof 5% cutter to improve thecohesion development of theresidual binder when applied instone seals.
It is therefore important, whenordering spray grade emulsions forfogspraying purposes, that thebinder supplier be requested toomit the cutter in the emulsionformulation. Contrary to the abovethe product is specially formulatedwith cutter to enable the binder topenetrate into the existingsurfacing and soften the agedbinder.
126
5. Application ofenrichment/rejuvenatorsprays
5.1 Road preparation
The road surface should be cleanas dust will cause the diluteemulsion or inverted cutbackemulsion to pick up on tyres.Patching and cracksealing isusually done after the applicationof rejuvenating sprays, especiallywhen applying proprietaryinverted emulsion.
5.2 Selection criteria foremulsions
The decision on which type ofemulsion to use will dependlargely on the most desirable flowcharacteristic of the emulsion. Thisis most critical to the applicationof the enrichment spray - i.e. the
low viscosity characteristics ofstablemix for maximumpenetration into surface voids,versus the quick breaking action ofspray grades. Stablemix emulsionsare more stable than spray gradesonce diluted. Of the stablemixgrades anionic is more commonlythan cationic due to the loweremulsifier cost.
5.3 Binder application rates
The texture of the existingsurfacing largely determines theapplication rate. A fine texturerequires a light fogspray whereasa coarse or open textured surfacecan take a heavier spray rate.
An indication of the maximumapplication rate that a surface cantolerate is when there are definitesigns of run off from the existingroad surface.
127
Condition Type of emulsion
Stablemix Spray grade Latexmodified
MSP
Coarse textured ** * * **
Dense textured ** * ! !
Flat gradient< 4%
** * * *
Steep gradient> 4% < 6%
! **refer par. 5.4
* !
Dirty surface * ! ! !
Cold temp. * ** * !
Hot temp. * * ! **
Trafficaccommodation
* ** * !
Table 1. ! = not suitable* = can be used** = most suitable
The typical spray rate for a 50:50diluted emulsion is 0.8 l/m² withthe maximum being not more than1.0 l/m² and the minimum 0.5l/m². The latter equates to a netresidual binder of 0.15 l/m² for a60% solids emulsion.
The lowest application rate is afunction of the minimum sprayrate that the binder distributor canspray accurately. Some guidelinesappear in Table 2, but theapplication rate should beadjusted on-site to avoid problemswith over application.
5.4 Binder content
The bitumen emulsion use forenrichment sprays is normallydiluted in a 1:1 ratio with water.This ratio can be varied toovercome certain constraints.However the lowest recommendedbinder content of the dilutedemulsion is 25% m/m. Dilutingthe emulsion further will weakenthe electrochemical charges thus
rendering the end productunstable.
In the event of steep grades it isrecommended that a spray grade
be used with a lower dilution of70:30 to prevent runoff. If theemulsion has to be transportedlong distances from the sourcethen consideration must be givento using a higher binder contentemulsion such as a cationic spraygrade 70, and to rather diluteon-site to reduce the transportcosts.
5.5 Dilution process
The water used for the dilutionmust be potable, free of solublesalts or suspended solids i.e. itshould be suitable for humanconsumption. It is recommendedthat the candidate water besubjected to a simple dilution testto check its compatibility with theproposed grade of emulsion.
If coarsening of the bitumen
128
Existingsurfacing
Diluted emulsion(l/m2)
MSP3TM
(l/m2)
Diluteemulsion
Residualbinder
MSP3TM Residualbinder
13mmsingle seal
1.0 0.30 0.6 0.27
13/6mmdouble seal
0.8 0.24 0.5 0.23
Cape Seal 0.5 0.15 0.5* 0.23
Asphalt 0.5 0.15 0.5* 0.23
Table 2. Application ratesNote. * = only if surface is open textured
particles in the emulsion occurs,then the water can be stabilisedby adding HCL for use withcationic grades and caustic sodafor anionic grades.It is best to dilute the emulsionon-site immediately prior tospraying particularly if cationicspray grades are used. Stablemixemulsion is chemically the moststable grade of emulsion fordiluting with water.
The water must always be addedvia a transfer hose to the bottomof the predetermined volume ofemulsion in the distributor whilecirculating in order to avoid theformation of lumps in the dilutedemulsion.
The diluted emulsion should beheated to 60°C to facilitate ease ofspraying.
5.6 Application procedure
Once the diluted emulsion/inverted cutback emulsion issprayed, it must be allowed to drywith no covering, before openingto traffic. The drying time is
affected by a number of factors,as described above, and adequatetraffic accommodation planning isneeded.
A trial section is essential to allowa known quantity of product to bespread over a predetermined area,and to allow the drying time to bemonitored. The trial section will
indicate whether overnight closureof the road will be required, andserves as a check on theapplication rate.
• any pools which develop maybe blended with washedcrusher dust or coarse sandprior to opening;
• spray inverted cutbackemulsion only when the roadtemperature is at least 20oCand rising;
• do not spray if rain isexpected;
• keep traffic off wet invertedcutback emulsions and avoidusing in residential areas;
• generally stop spraying by14h00, unless the road isclosed overnight;
• in any areas of handapplication, exercise care notto over-spray;
• place sand berms if steepcross-falls are encountered.
About 6-10 weeks should beallowed before a new bitumenstone seal is placed on a roadtreated with a fogspray or invertedcutback, and ball penetration testsare essential for the seal design.
6. Common problems
6.1 Poor penetration
• Dirty surface - prevents thebinder from flowing into thesurface voids.
• Too dense road surface - notsufficient voids in thesurfacing for the binder.
129
Stablemix emulsion is chemically the most stable grade of emulsionfor diluting with water.
• Emulsion breaks too rapidly,thus not allowing sufficienttime to flow into the voids.
• Application rate too low, sothat the binder is not able to‘wet’ and flow into thesurface voids.
6.2 Pickup on tyres
• Over application resulting inhigh residual binder;
• Road opened too early totraffic (before the emulsionhas broken);
• Presence of cutter in theemulsion;
• Dusty road surface;• Road surface temperature
50°C in the case of dilutedemulsions;
• Fine textured surface
6.3 False break
Emulsion develops a skin withoutbreaking at the bottom. This isparticularly a problem with latexmodified emulsion when applied inhot weather.
6.4 Foaming
Foaming is a common problemwhen working with a high dilutionratio of water to emulsion. A smallamount of illuminating paraffin(one litre) can be sprinkled on thesurface of the diluted emulsion inthe sprayer to reduce foaming.
7. Cost-effectiveness
With most Road Authorities facingthe dual problem of a rapid ageingroad network and limited financialresources, the use of dilute
emulsion or inverted cutbackemulsion offers a low risk andcost-effective solution to extendthe life of existing surfacings untilsuch time that a reseal is required.Depending on the state of theexisting surfacing, the use ofdilute emulsions can delay theneed to reseal by up to threeyears, and some proprietaryproducts by up to six years.
Again, depending on the textureand permeability, an existingstone seal can be fogsprayed orrejuvenated up to three timesbefore resealing is required. TRH 3also prescribes that porous anddry surfacings be treated withdiluted emulsion prior to resealing.This is to prevent the absorptionof the newly sprayed binder whichoften results in loss of aggregatefrom the new seal.
Yet the proof is on the road, andactual inspection of roads treatedwith proprietary products such asMSP 3, some up to 5 yearspreviously, showed excellentresults. Chiselled open sections ofvarious treated surfacings, showedthat the inverted cutback emulsionhad penetrated the road surface5-10mm or greater. The enrichedbitumen was black and alive,which contrasted with the greyaged bitumen at the bottom of thesurfacing and in adjacent roadsections that had not beentreated. �
References:
Colas Products and Services CD-ROM,TRH 3 (1998),Gerry Van Zyl, Consulting Engineer
130
Road engineers in southernAfrica have long recognisedthe long term benefits of
using hot modified binders for theconstruction of surfacing seals,and the use of these binders hassteadily increased over the last 10to 15 years.
However with the increasedviscosity properties associatedwith hot modified binders,adequate adhesion between thebinder and the stone becomesmore critical than when usingconventional binders. Thereforethe aggregates used in surfacedressings must be precoated inorder to reduce the surfacetension between the coldaggregate surfaces when spreadon the rapid cooling thin film ofnewly sprayed modified binder. Tothis end it becomes necessary toprecoat the aggregates with a fluidon-site or at the stone source afew days before use. The otherbenefits of precoating theaggregate are:
• Any residual dust remainingon the aggregate is bound bythe precoating fluid, ensuringexcellent adhesion of theaggregate to the binder,thereby minimising the
• amount of loose aggregatethat can damage vehicles;
• The surface has a uniformblack appearance and formsa sharp contrast withroadmarkings, making nightdriving considerably safer;
• No diluted emulsion coverspray is required.
Use of tar based precoatingfluids
Tar based precoating materialshave traditionally been usedsuccessfully for this purpose formany years, but these materialshave the following disadvantages:
• Irritation to the skin and eyesand in some cases respiratorytracts.
• When surfacing is performedin residential areas,complaints may be receivedfrom the residents due to thepungent odour.
• Softening of the rubberconveyor belts on chipspreaders and prematuredeterioration of the front-endloader and roller tyres.
While bitumen does not normallyraise environmental concernsbecause of its low toxicity, studies
131
Bitumen based precoatingfluid forsurfacedressing Kobus Louw
Research and Development ManagerColas SA
have shown that prolongedcontact with coal tar pitch maypresent carcinogenic hazards.Colas recognised the need for amore user-friendly pre-coatingfluid about five years ago, and thenon-tar based Colkote STM wasdeveloped. Since the introductionof this product a number of majorsurfacing projects have beensuccessfully completed.
Properties of bitumen-basedprecoating fluids.
Typically, the new generationprecoating fluid is a bitumen-based cutback blended fromselected petroleum derivatives andspecial chemical additives. Theproduct is environmentallyfriendly, non-irritating and after ashort curing period, is completelyodourless. It can be used with allbituminous binders, includingemulsions without the risk ofincompatibility problems.
A typical bitumen-basedprecoating fluid specification isshown in Table 1.
Application
The chemical additives inbitumen-based precoating fluidsmake them suitable for use withall local aggregate types, including“difficult” aggregates such as
quartzites and granites. In thelatter case the precoatedaggregates will tend to have abrownish appearance. While thismay not be as aestheticallypleasing as the pitch-black colourachieved with tar based precoatingfluids, the slight discolouration willnot affect the binder/aggregateadhesion. Such coated aggregatewill also initially be slightly tackierthan the tar based products, butthis phenomenon will disappearwithin a few hours of trafficking.
132
Property Requirement TestMethod
min max
Density @ 250 C (kg/l) 0.922 0.928
Dynamic viscosity @ 250C(cps)
75 120 ASTM D4402
Distillation to 3600C (% v/v)To: 1900C
2250C2600C3160C
0155080
15557595
ASTM D402
Residue from distillation to3600C (% v/v)
42 48 ASTM D402
Penetration of distilled residue(0,1mm)
300 ASTM D 5
Table 1
The type of aggregate being usedwill dictate the optimum appli-cation rate. Trial quantities shouldfirst be prepared to determine theoptimum application rate. Typicalapplication rates are shown inTable 2 below.
Bitumen-based precoating fluid isgenerally supplied in either bulk or200 litre non-returnable drums.
Conclusion
In line with the worldwide trend
towards worker health, safety andenvironmental conservation, theSouth African roads industry nowrecommends that materialspecifiers move away fromtar-based products towards moreuser-friendly bituminous products.
The possibility of incurring a smallpremium to the overall surfacingcost due to higher applicationrates, and/or product price, ismore than justified by the benefitsto the environment, and to overallproduct quality.�
133
Typical application rates for various stone sizes (l/m3)
Nominal stone size (mm) 6,7 9,5 13,2 19,0
Colkote STM 14-18 13-17 12-16 11-15
Table 2. Application rates
1. Introduction
The Natref refinery recentlyunderwent a major expan-sion program designed to
increase the production capacityby 20 %.
Changes made to the refineryinfluencing bitumen productionwere the addition of crude andvacuum pre-flash columns. Thecrude pre-flash column removeslight ends from the crude enteringthe atmospheric distillationcolumn, while the vacuumpre-flash column removes lightgas oils from the reduced crudeentering the vacuum distillationcolumn.
It is the inclusion of the crudepre-flash column thatdistinguishes the Natref refineryfrom other conventional refineries.
After recommissioning in October2002 penetration and cutbackbitumen product quality had to beverified, to ensure that no changein the product quality hadoccurred.
The results obtained indicate thatthe quality of the bitumenproduced at the Natref refinerywas maintained subsequent to thechanges.
2. Primary bitumen properties
2.1 Specification Testing
The penetration grade and cutbackbitumen samples were submittedto the Natref laboratory for fullspecification testing according toSABS 307 and 308 respectively.Penetration grade and cutbackbitumens produced before theexpansion project were used asreference samples to evaluate theimpact of the expansion project onthe bitumen quality. The results ofthe 80/100 penetration grade andMC 30 are presented to illustratethe quality of the new product.
2.2 Rheological Properties
The bitumen samples were alsosubmitted to a temperature sweepon a Paar Physica Dynamic ShearRheometer (DSR) before and afterRTFOT (Rolling Thin Film OvenTest).
The following test conditions wereused:
• Temperature range: 80ºCdecreasing to -20ºC (100measuring points)
• Frequency: 1 Hz or 10 1/sradials
• Amplitude: 10%• Duration: 40 minutes
134
Bitumen quality:
Natref production afterexpansionprogramme
Anelize Loftie-EatonBitumen Specialist
Sasol Oil R&D
• Sample size: ~0.5 (±0.05)grams
• Gap size: 1 mm
2.3 Force Ductility
Force-ductility tests wereperformed on the bitumensamples produced afterimplementation of the expansionproject and compared to thereference samples to assess thelow temperature durability. Theforce-ductility was done on all thesamples before and after RTFOT.
The following test conditions wereused:
• Temperature: 10ºC & 15ºC• Extension rate: 50 mm/min
2.4 Wax and asphaltenecontent
The wax and asphaltene contentwere determined using Total321/83 method and UOP 614method respectively at the Natreflaboratory. The asphaltenes werealso done according to the ASFAN02 Extractor method.
2.5 Properties of SecondaryBituminous Products
Bitumen samples were submittedto Tosas for evaluation of theeffect of the refinery changes onthe secondary products, such asanionic and cationic bitumenemulsions, polymer modifiedbitumen and bitumen rubber.
135
Properties Units Limits Old80/100
New80/100
Viscosity @ 600C Pa.s 75-150 125 130
Viscosity @ 1350C Pa.s 0.15-0.40 0.31 0.34
Penetration @250C/100 g/5 sec
0.1 mm 80-100 90 87
Softening point 0C 42-51 46 47
Spot test % Xylene 30 max 25 25
After RTFOT
Mass change % Mass 0.5 max 0.11 0.09
Viscosity @ 600C % oforiginal
300 max 140 189
Softening point 0C 44 min 48 52
Retainedpenetration
% oforiginal
50 min 70 64
Increase insoftening point
0C 9 max 2 5
Table 1. Penetration grade bitumen produced after the implementationof project 2000
3. Results and Discussion
3.1 Specification testing
The results of the comparisonsbetween penetration grade andcutback bitumens before and afterthe implementation of theexpansion project, being similar,confirm that the quality of thebitumen produced wasmaintained. The comparison alsoconfirms that the quality of thebitumen produced after thechanges on the refinery is thesame.
3.2 Comparison of Rheologicalproperties
During the temperature-sweep thefollowing rheological parameters
were measured:
• Loss Modulus (Viscouscomponent)
• Storage Modulus (ElasticComponent)
• Damping Factor:
Damping Factor = loss modulusstorage modulus
The damping factor is anindication of the visco-elasticbehaviour of the vacuum residue.A damping factor >1 indicates thatthe viscous componentpredominates and a dampingfactor <1 indicates that the effectof the elastic component is larger.
Therefore, the temperature atwhich the damping factor is 1, aswell as the positioning of the
136
Properties Units Limits OldMC 30
NewMC 30
Kinematic viscosity @600C
cSt 30 - 60 49
Distillation @ 101.325kPa abs
Distillate (v/v) of totaldistillate to 3600C
Up to 1900C vol% 0-15 1 0
Up to 2250C vol% 15-60 40 33
Up to 2600C vol% 50-85 72 68
Up to 3160C vol% 80-100 93 92
Residue fromdistillation to 3600C
(by diff)
vol% 50 min 58 63
Penetration @ 250C onresidue fromdistillation
0.1 min 90-180 138 149
Table 2. Cutback bitumen produced after the implementation of project 2000
curves relative to one-another,can be used to judge the relativetemperature susceptibility ofbitumen.
Comparison of the old 80/100 andnew 80/100 curves of thetemperature sweeps indicated thatthe bitumen produced before andafter implementation of theexpansion project performssimilarly in terms of rheologicalbehaviour. The curve of the new80/100 lies beneath the curve ofold 80/100, indicating that thenew 80/100 is less temperaturesusceptible.
3.3 Force Ductility
Although it is not a requirementof the SABS specification, forceductility analyses were performed.The force-ductility results indicatethat the penetration gradebitumen samples behave in a
similar way to their respectivereference samples. This test is anindication of the durability andtenacious behaviour of thesamples.
3.4 Wax and Asphaltene
Wax and asphaltene resultscompare well with referencesamples.
3.5 Properties of SecondaryBituminous Products
Tosas produced and evaluated theentire range of secondary productsusing this bitumen. Theseproducts include:
• All grades of bitumenemulsions
• Homogeneous modifiedbitumens
• Non-Homogeneous modifiedbitumens
137
Comparison of the damping factor for 80/100 bitumens
0.01
0.1
1
10
100
1000
-20 -15 -10 -5 0 5 15 20 25 30 35 40 45 50 55 60 65 70
Temperature,°C
Old 80/100
New 80/100
Dam
pen
ing
Facto
r.ta
n(d
elt
a)
Figure 1: Comparison of the damping factor for 80/100 penetration gradebitumens
These evaluations confirmed thatthe base binder quality is thesame as that supplied prior to theupgrade.
4. Consistency of Production
Since the implementation of theexpansion project, six 80/100 runshave been completed. Sampleswere taken at regular intervalsduring each run to determine theconsistency of the product. Noproblems were observed with theconsistency of the viscosity andpenetration values. See table.
5. Conclusion
The results obtained confirm thatthe bitumen produced after theimplementation of the expansionproject is of the same quality asbefore the modifications to therefinery.
Comparative results wereobserved for all the penetrationgrade and cutback bitumenproduced before and after theexpansion, in terms of both thephysical and chemical properties.
The comparison also confirms thatthe additional pre-flash columnsadded to the manufacturingprocess have no effect on thebitumen quality.
The consistency and quality offinal bitumen products producedafter implementation of theexpansion project are similar tothat experienced by the marketsince 1995. This is applicable toboth primary and secondarybitumen applications.�
Acknowledgments
The contributions and inputs of K Raijmakers, P Roets,J van Heerden, D Sadler and J Muller to this project aregratefully acknowledged.
138
Comparative Force-ductility curves of 80/100
Ductility (cm)
Fo
rce
(H
)
0
10
20
30
40
50
60
0 2 4 6 8 10 12 14 16 18 20
Old 80/100
New 80/100
Figure 2: Comparison of the Force-ductility curves of 80/100penetration grade bitumens (See 3.3)
Background
Adequate compaction ofasphalt layers is essential forthe achievement of
acceptable pavement durabilitystandards. While there are manyinfluences which can impact oncompaction — weather, equip-ment, lay-down temperature etc.— it is my opinion that rapidcooling is the primary cause oflow densities being achieved inthin HMA mats.
A practical guideline for estimatinghow much time is available inwhich to achieve compaction (theso-called “compaction window”)can be a great help in assessingthe parameters influencingcompaction, and this articleattempts to develop such aguideline.
Examination of the issue revealsthe following:
• Mat thickness has asignificant effect on thecooling time. On thin layers,and in unfavourable condi-tions, the time available forcompaction may be as littleas a few minutes. Under thesame conditions, a thick matwould retain its temperaturefor up to an hour or more.
• A further problem is that,using the same rollers, it ismore difficult to obtainconsistently good density onthin mats compared withthick ones.
In previous Digests1, I reported onthe results of infrared imageryinvestigations on compactionwindow times for thin HMA pavedin summer and in winter in CapeTown.
This article converts these findingsplus other information (seeReferences), into a practical guidefor estimating the compactionwindow for varying mat thick-nesses, temperature conditionsand wind strengths.
How the mat cools through itsdepth
A drawback of infrared imagery isthat it reads surface temperatureonly, and ignores temperatures inthe middle of the mat and lowerdown — which may be consider-ably lower under the influence ofbase temperature and otherfactors.
Figure 12 is an illustration only ofhow a 20mm thick mat may coolover time, from a deliverytemperature of 1500C.
139
Estimating the compaction time forhot-mix asphalt
A Practical GuideJulian Wise
Technical DirectorZebra Bituminous Surfacing
A guide for the compactionwindow
The factors which most seriouslyaffect this window are:
• Base and air temperatures• Delivery and paving
temperatures• Wind chill effect• Mat thickness
From all the information available,we can construct a practical guidefor estimating compaction windowtimes to allow for these factors.This guide can then be used towork out the maximum rollingzone distance for each situationwhere there is risk of rapidcooling.
Assumptions for the guide
Certain conditions are fairlystandard for the majority of thinHMA paving:
1. Weather conditionsencountered when pavingthin mats in South Africaoften range from:
• A low of about 100C at thestart of paving in winter, orwhen paving at night;
• Around 200C in thein-between seasons, orin-between times of day;
• 300C and above during thehot summer days; and
• Other conditions can beinterpolated.
2. Base temperatures areusually higher than airtemperatures:
• Up to 30% higher in coldconditions, and to 60%higher in hot weather.
E.g. (air = 100C, base =130C) and (air = 300C,base = 500C)
140
20mm Thick Mat
20 min 10 min 5 min 3 min 1 min
Temperature (Deg. C)
Th
ickn
ess
)m
m)
20 30 40 50 60 70 80 90 100 110 120 130 140 150
0
5
10
15
20
Figure 1
Note: At the start of rolling, the surface is cooler than the centre (usually by 100 to 150C for thin mats)3
The base has a strong cooling effect on the lower matAt rolling temperatures, the surface temperature gives a reasonable indication of the average mat
temperature.
3. Delivery temperatures
These are around 1500C for HMAmade with 60/70 pen bitumen, butdrops to about 1350C immediatelybehind the screed.
4. 60/70 pen bitumen
For this material the compactionwindow is usually taken to end atabout 800C.Compaction can still be achievedat lower temperatures, butbecomes increasingly difficult.
5. Wind chill
The influence of cool or cold windon the rate of cooling can beserious. This guide is thus basedon windless conditions, with acorrection chart for estimating the% reduction in compaction windowtime for varying wind speeds.
6. Thick mats
Once a mat is 50mm thick ormore, the fear of rapid coolingceases, and there is usually morethan enough rolling time.
7. Appendix A
This provides a guide to estima-ting wind speeds.
THE GUIDE (Figures 2 and 3)4:
Using the guide
Two recently completed contractsin Cape Town are used to illustratethe use of the guide.
Contract A. TOWNSHIPROADS
• 25mm SABS wearing course• Air temp = 140C• Base temp = 180C• Wind = 25 km/hr• From Figure 2: compaction
time = 9 mins.
141
20
25
3030
35
40
50
45
Mat
thic
kn
ess
(m
m)
Compaction window time (minutes)
2015105 25 30 35 40
Wind speed = zero
Temp. Of mat behind paver = 135 deg C
Cut-off temp. For compaction = 80 deg C
Cooling rate of HMA mats for:
Air 10 deg., Base 10 - 15 deg C
Air 20 deg., Base 20 - 30 deg C
Air 30 deg., Base 30 - 50 deg C
Effects of wind on compaction window time
Wind speed (km/hr)
%le
ss
com
pact
ion
tim
ea
0 5 10 15 20 25
0
-5
-10
-15
-20
-25
-30
Figure 2
Figure 3
• From Figure 3: compactiontime corrected for wind = 6mins.
In that situation 6 mins was tooshort in which to achievecompaction. It meant that thecalculated rolling zone was only18m, which is clearly not practical!
However, this was a “must pave”situation and an instruction topave was given — with the resultthat 80% of the cores failed toachieve the 95% minimumMarshall density!!
Contract B. MAJOR ROAD(paved at night in winter)
• 35mm Colto Medium wearingcourse
• Air temp = 100C• Base temp = 110C• Wind = 3km/hr• From Figure 1: compaction
time = 16 mins
• From Figure 2: compactiontime corrected for wind = 15mins.
This was a production job, straightpaving with no hindrances. Thecalculated rolling zone was 40m,which was quite adequate,allowing us to achieve the required94% Rice density!!
So even though a SABS mix isnormally easier to compact than aColto Medium, the SABS spec was95% Marshall vs 92% Rice for theColto Medium and temperatureswere lower in Contract B, thegreater mat thickness and lack ofwind in Contract B made all thedifference to the density results.
Conclusion:
The historically accepted practiceof specifying 25mm HMA for“township” roads is fraught with
142
Windspeed(km/hr)
Description Guide
0 - 2 Calm Smoke rises vertically
2 - 4 Light air Smoke drifts in direction of wind
4 - 7 Light breeze Wind felt on face, leaves rustle
7 - 11 Gentle breeze Wind extends a light flag, leaves inmotion
11 - 18 Moderatebreeze
Wind raises dust and light paper
18 -25 Fresh breeze Small trees sway, wavelets form onwater
25 - 32 Strong breeze Large branches sway, whistling inwires
32 - 36 Near gale Whole trees move, affects walking
APPENDIX A. Wind speed guide2
risks, when one considers thequality and finish of bases,resultant variations in thicknessand rapid cooling of asphalt.
The current exercise by Sabita onUltra Thin Layer Asphalt (UTLA)should bring better understandingand assist in reducing the risk.�
REFERENCES:
1. Sabita Digests 2000 & 20022. Compaction and Paving, Theory and PracticeSvedala Dynapac Publication No. IHCCCAPEN13. Willoughby: “Temperature and DensityDifferentials in Asphalt Concrete Pavements”4. PaveComp software programmeMetso Dynapac International High CompactionCentre
143
Zebra Ad
144
Background:
In a joint initiative during thelatter part of 1999, ZebraBituminous Surfacing and
Much Asphalt explored thefeasibility of developing a thinlayer hot-mix asphalt surfacingseal. This product was envisagedas an alternate to slurries andother surfacing seals, while at thesame time delivering the superiorsurface finish commonlyassociated with hot-mix asphalt.
During a visit to Australia, whichincluded attendance at the AAPAWorld of Asphalt Pavementsconference in February 2000, itwas demonstrated that products ofthis nature enjoy a reasonabledegree of popularity, and are stillin demand.
The development team came upwith the following productdescription:
“An asphalt mix, specificallydesigned to provide an even,durable, waterproof material forthe resurfacing of light dutypavements. The product must bespecially formulated to enable theapplication of a thin layer ofasphalt (average less than 13mmthick) which provides the benefits
of conventional surface seals whilealso greatly enhancing ride qualityand appearance”.
MICROPAVETM has a maximumsize aggregate of 4.75mm, and abinder content of 5.5%. Thisbinder is modified to ensuredurability and flexibility. Theproduct is placed by conventionalpaver and compacted in the usualmanner.
It is important to emphasise thatthis product must be regarded asa surface seal, since the naturalinclination is to categorise it in thesame context as continuouslygraded wearing courses, most ofwhich have structural value andare subjected to stringentcompaction criteria.
The product has been registeredas a brand name owned by Zebraand Much, hence the reference“ZM12".
145
MICROPAVE ZM 12:
A viable off-the-shelfsurfacingsolution
Andrew ThompsonDirector
Zebra Bituminous Surfacing
John OnraëtDirector
Much Asphalt
Performance Characteristics
The marketing of the appropriateapplication of the product wasapproached with a certain degreeof caution, as a “fix all” approachwas bound to create dangerouslyhigh expectations.
In January 2000 an initial trialsection was undertaken inpartnership with OostenbergMunicipality on NooiensfonteinRoad. This test location wasspecifically chosen for it’s highvolumes of heavy and light traffic,and was thus deemed to beextreme in terms of the possibleareas in which the product couldbe applied in the future.
A total of 12 trial sections,including the one referred toabove, were constructed betweenJanuary 2000 and May 2000, andall have been monitored annuallysince commencement.
The criteria used for evaluationare:
• Surface texture: bleeding,shoving, reflective cracking,and surfacing loss
• Permeability• Skid resistance• Channel tie in quality• Joint quality• Ride quality at manholes and
bell tobies
Overall performance of theproduct has thus far been verysatisfactory. Some of the mainobservations are:
• The surface is not susceptibleto bleeding.
• There has been very limitedshoving of the mix in areas ofhigh stress due to braking orturning.
• The layer is sensitive torecently applied cracksealant, especially thebandage method. Someshoving and reflection of thesealant occurs.
• The layer is sensitive toreflective cracking, whichmanifests itself within a yearof application.
• Permeability is low withresults of 0.1 to 0.2 litres perhour.
• Skid resistance wasmeasured using comparativeanalysis with conventionalasphalt, using an advanceddriving instructor in wet anddry conditions. Despite thesmooth appearance, theresults were comparable with
conventional asphalts andseals, which can be mainlyattributed to themicro-texture of the mix.
• Joints and tie ins aregenerally neat.
Comments on the application andlimitations of the product are:
• It is paved over existing blacktop and concrete roadsurfacing, not directly on tobasecourse, and is verysuitable for resurfacing lightduty pavements such as
146
Skid resistance .... results were comparable with conventionalasphalts and seals.
residential roads and carparks.
• It is a suitable surfacingmedium for roads that have a60km/hr speed limit
• The profile of the existingroad must be suitable for thepaver screed configurationsuch that no ridges/crowns orcurved surfaces interfere withthe screed or the desiredtarget thickness.
• Minor levelling layers can bedone up to 8mm. Themaximum layer thicknessshould not exceed 20mm.The target thickness shouldbe 12-14mm.
• Normal repairs must becarried out prior to paving.This includes patching offailed areas, crack sealing,trench crossingreinstatement, levellinglayers in low areas,adjustment of covers andframes if necessary, andrepair or replacement ofdamaged kerbs and channels.
• Cracksealing must be left tocure for a minimum of 6weeks before application ofthe layer.
• Tack must be applied evenlyand timeously, so that thenew layer bonds to theunderlying surface. It isimportant that existing roadmarkings be tacked properly,and it may be necessary toroughen these surfaces first ifthe paint is thick and verysmooth.
• Keys along kerbs and orchannels are not essential,however it is important thatthe beginning and end ofeach paved section is tiedinto a transverse key. Wherea paved section passesthrough a road intersection, akey should be cut for theunconfined edge. The depthof the keys should not exceed20mm.
Since January 2000 MICROPAVETM
has been used extensively withinthe Cape Town area and thegreater surrounds, with480 000m2 already placed.Applied correctly in terms of “fitfor purpose” usage, the product isa valuable addition to theoff-the-shelf range of surfacingproducts.�
147
148
Author Index
Author Page
Blaauw, Pierre 33Church, Michael 120de Beer, Morris 90Distin, Trevor 101,123Henderson, Mervyn 97Horak, Emile 48Jenkins, Kim 58, 88Kleyn, Eduard 41Levin, Mannie 112Loftie-Eaton, Anelize 134Long, Fenella 84Louw, Kobus 131Mashatola, Daniel 28Myburgh, Piet 80Onraët, John 44, 67, 145Ross, Don 13, 20Rossmann, Dennis 37Sampson, Les 64, 109Sadzik, Elzbieta 97Steyn, Wynand 41Taute, Authur 73Theyse, Hechter 84Thompson, Andrew 145Wise, Julian 139
149
Sabita ManualsManual 1 Construction of bitumen rubber sealsManual 2 Bituminous products for road constructionManual 5 Manufacture and construction of hot-mix asphaltManual 7 SURF+ Economic warrants for surfacing roadsManual 8 Bitumen safety handbookManual 9 Bituminous surfacings for temporary deviationsManual 10 Appropriate standards for bituminous surfacingsManual 11 Labour enhanced construction for bituminous
surfacingsManual 12 Methods and procedures - Labour enhanced
construction for bituminous surfacingsManual 13 LAMBS - The design and use of large aggregate
mixes for basesManual 14 GEMS - The design and use of granular emulsion
mixesManual 16 REACT - Economic analysis of short-term
rehabilitation actionsManual 17 The design and use of porous asphalt mixesManual 18 Appropriate standards for the use of sand asphaltManual 19 Technical guidelines for bitumen-rubber asphaltManual 20 Sealing of active cracks in road pavementsManual 21 ETB: The design and use of emulsion treated basesManual 22 Hot-mix paving in adverse weatherManual 23 Bitumen Haulier’s Code: Guidelines for Loading
Bitumen at Refineries
Asphalt Academy publications
TG1 Technical Guidelines: The use of modified binders inroad construction
TG2 Interim Technical Guidelines: The design and use offoamed bitumen treated materials
150
Training Guides
TRIP — Technical Recommendations in PracticeHMA — Hot Mix Asphalt Training seriesHSE — Health, Safety and Environmental Guidelines
for Bitumen and Coal Tar ProductsRDP — Roads Develop People workshop notes & CD
Sabita Video Training AidsVideo series on testing of Bituminous Products
Bitumen
AV-1 Penetration test / Softening point (ring and ball)AV-2 Spot test / Rolling thin film oven testAV-3 Brookfield viscosity / Ductility
Bitumen Emulsion
AV-4 Sayboldt furol viscosity / Water content of emulsionsAV-5 Sedimentation value of emulsions / Residue on sievingAV-6 Coagulation value with chippings / Coagulation value with
Portland cementAV-7 Binder content of slurry / Particle charge test
Hot-mix Asphalt
AV-8 Optimum binder content for asphaltAV-9 Marshall testAV-I0 Binder content / Moisture contentAV-11 Static creep test / Immersion indexAV-12 Rice’s density and binder absorption/Bulk relative density
and voids
Bitumen Rubber
AV-13 Ball penetration and resilience test / Dynamic viscosityAV-14 Compression recovery / Flow testAV-15 Bulk density of crumb rubber / Grading and loose fibre
test of crumb rubber
Video series on Blacktop Roads
AV-21 Black-top roads for reconstruction and developmentAV-22 Black-top surfacing and repair (with Instructor Training
Manual)AV-23 Pavement surfacing and repairs for black-top roads
Video series on Hot-mix Asphalt
AV-25 ManufactureAV-26 PavingAV-27 Compaction
151
For order information contactSabita at:
152