asphaltprofessional - institute of asphalt technology · pavement design and maintenance technical...

Pavement Design and MaintenanceTechnical Paper: Fast Curing Cold Mix Asphalt for Highways and Airfield Pavements

Rejuvenator trial in Norwich

Branch Reports

and your usual features

AsphaltProfessionalJOURNAL OF THE INSTITUTE OF ASPHALT TECHNOLOGY

No 58 • NOVEMBER 2013

www.instituteofasphalt.org

National Conference 2014“BRIDGING THE GAP”18-19 June, St. Andrews

Full details and online booking soon at

www.instituteofasphalt.org/conferenceSponsorship packages available, for details contact Andrew [email protected]

The Institute of Asphalt TechnologyPO BOX 17399, Edinburgh, EH12 1FR

01506 238 397 | [email protected] | www.instituteofasphalt.org

Wednesday, 18 June 2014Training Day Queensferry Crossing / St. AndrewsGolf Tournament St. AndrewsPresident’s Dinner St. Andrews

Thursday, 19 June 2014National Conference & Exhibition St. Andrews

© 2013 Institute of Asphalt TechnologyNo material in this issue may be reproduced in any form except by permission in writing from the Institute Secretary.Contributors express their personal and professional opinions in this publication and their views are not necessarily those of the Institute of Asphalt Technology.

Designed by Sharon Levett • [email protected]

Welcome Back!

Contents

The Institute of Asphalt TechnologyPO BOX 17399 • Edinburgh • EH12 1FRtel 01506 238 397email [email protected] www.instituteofasphalt.orgISSN 1479-6341

President Arthur Hannah, FIATVice President Geraldine Walsh, MIATEditor Pippa Birch, MIATBusiness & Development Manager Russell HunterHon Treasurer Ray Wood, MIATSecretary Michael Atkinson, FIAT

5 PRESIDEnT’S VIEw

6 InSTITuTE uPDATE and details on Peer Review

7 EVEnTS

8 InSTITuTE nEwS Scottish, East Midlands, South East, North East, Western, Irish & Pennines Branches

16 CASE STuDY A case study on a rejuvenator trial in Norwich

18 TECHnICAl PAPER Fast Curing Cold Mix Asphalt for Highways and Airfield Pavements

25 REVIEwS TRL Report PPR666

26 COnFEREnCE REPORT Low Temperature Asphalt

36 nARC Report on the meeting of the Nottingham Asphalt Research Consortium

39 ASPHAlT EXCHAngE

41 BOlDEn nuggETS – nEw!

42 ASPHAlT PEOPlE Chris Hudson

43 ASPHAlT AMuSEMEnT

So you’ve opened this copy, which means you must have enjoyed the last

one? I do hope so. We had some very favourable and constructive comments

from various quarters and I thank those of you who took the time to let me

know what you thought. Of course, more feedback is always welcome.

I can’t believe the time for this issue has come around so quickly. It only seems

like a week ago that we were putting the finishing touches to the new look

AsPro and wondering whether we had done a good job. I was so pleased with

the final result, the team worked very hard. I know we have a way to go, but we

are constantly improving on what we are doing and the journey we take to get

the finished publication.

Since the last issue, IAT Council have had a meeting in which we discussed

the direction of the IAT, including promotion and publication. We need to raise

awareness of the valuable educational work we do within the industry, which

means promoting ourselves and, ultimately, pulling in more members. As part

of our planning for promotion, Arthur, Jukka, Ray and I attended the Highways

Magazine Awards in October, which turned out to be a lovely evening with

some very worthy winners – and nominees. The IAT would like to get involved

in industry schemes and are thinking about sponsoring an award next year,

so it was an ideal way to check out how it all works. We also managed to

get a few cheeky AsPro’s around the room for people to thumb through!

In this issue we welcome back Bob Bolden with his Bolden Nuggets (get it?!).

Some of you may remember his amusing ‘President’s View’ a few years back.

Bob has an interesting take on life and the industry – we felt it would add

another dimension to the amusement pages at the back of the publication.

It also might provoke a response from our readers too…

Our next issue in February 2014 will be focussing on utility Reinstatements.

Please contact us if you would like to contribute your thoughts, technical papers

or have a product you would like to advertise – email address, as always,

is [email protected]

Copy date for the next issue is 15th January 2014.

See you next year – happy reading!

Pippa Birch Editor

[email protected]



AsphaltProfessional

Front Cover Kessock Bridge

More details on Page 8

National Conference 2014“BRIDGING THE GAP”18-19 June, St. Andrews

Full details and online booking soon at

www.instituteofasphalt.org/conferenceSponsorship packages available, for details contact Andrew [email protected]

The Institute of Asphalt TechnologyPO BOX 17399, Edinburgh, EH12 1FR

01506 238 397 | [email protected] | www.instituteofasphalt.org

Wednesday, 18 June 2014Training Day Queensferry Crossing / St. AndrewsGolf Tournament St. AndrewsPresident’s Dinner St. Andrews

Thursday, 19 June 2014National Conference & Exhibition St. Andrews

Highlights

A case study on the rejuvenator trial in Norwich

Bob Noakes provides a report

on the trial of Reclamite on the

A140 Inner Ring Road, Norwich.

Low Temperature Asphalt Conference

Report provided by Tony Stock on

the conference held at the National

Motorcycle Museum in June.

Report on the meeting of the Nottingham Asphalt Research Consortium (NARC)

Round up of presentations made concerning

temperature effects on warm mix asphalt

performance, the influence of moisture,

the role of contact pressure and multiscale

permanent deformation behaviour.Asphalt People – Chris Hudson

As Chris rejoined the Council this

year, he tells us about his plans to

assist the IAT in moving forward.

26 36

42

16 18

Kessock bridge: Surfacing the bridge

A report on the technical presentation

provided to the Scottish Branch regarding

the resurfacing of Kessock Bridge.

8

CASE STUDY TECHNICAL PAPER

4 Asphalt Professional • November 2013 www.instituteofasphalt.org


Fast Curing Cold Mix Asphalt for Highways and Airfield Pavements

This paper reports the stiffness, axial deformation

and XRD analysis of a new cold mix asphalt

developed for use in highway and airfield pavement

structural layers including surfacing pavement.

PRESIDENT’S VIEW

www.instituteofasphalt.org Asphalt Professional • November 2013 5

President’s ViewI am pleased to be able to report on the

recent Branch Chairman’s meeting which

took place before my first Council meeting

as President. Only one branch was not

represented at the meeting so it was

gratifying to see the effort put in by

your branch chairmen.

Ray Wood outlined the current financial

position of the institute and explained the

progress that is being made to bring all

the branch accounts under the roof of

one bank to enable the year end accounts

to be undertaken more efficiently. This

should be in place in the next 6 months

or so. The Chairmen all gave a brief review

of the activities in their branch and also

highlighted any concerns their branch

had about the Institute. The health of the

branches varies considerably; some hold

meetings nearly every month, all of which

are well attended whereas other branches

struggle to get attendees at one or two

meetings a year. However the view from

virtually all the Chairmen was a positive

one, with the expectation that things

are slowly getting better. Only the West

Midlands branch has not held any meetings

in the last year and this formed the heart of

a discussion about the size and boundaries

of the branches in England. The Council will

look at the branch population in respect to

the boundaries and ease of travel and will

see if there are any changes needed. In

the meantime, every effort will be made

to ensure that at least an AGM has been

held in all branches this year.

If any of the members in the West Midlands

have any suggestions about reinvigorating

the branch or any suggestions about

changes to the boundaries then please let

Russell have your comments so they can be

passed on to Council or feel free to give me

a call to discuss it.

The need for CPD was highlighted and we

are pleased to say that Russell Hunter has

done a significant amount of work on this.

We will shortly have an online system that

will be easy to use. This will be of great

benefit to all of our members when they

are called upon to show their CPD activities

in relation to their employment.

The view from the Chairmen was a positive one

The Worshipful Company of Paviors have

in recent years presented certificates of

merit to suitably qualified people who

have come up through the experience route

rather than the academic one. They have

3 levels – Apprentice, Journeyman and

Master Pavior – and our membership review

committee has vetted these applicants

on their behalf. We have now moved this

forward to enable them to the get the most

suitable candidates by asking our branches

to nominate suitable applicants. Brian

Downes is putting together a process for

this which will be issued early in the New

Year. The suitable applicants will be vetted

by our membership review committee and

the successful applicants will be passed on

the Paviors and then invited to London for

a grand award ceremony in conjunction

with all the other Worshipful Companies.

We will be relying on the members to

suggest suitable applicants to their Chairman

so look out for the notice about this early

next year.

The intake into the first year of the Derby

course has improved slightly this year

and we have also had a small number of

students doing the 1 year course, which

has bolstered the small number moving into

the third year. We are pleased and grateful

to see that the industry is supporting this

course, especially as times are still hard.

We hope that this will continue and that

the numbers will continue to increase

over the coming years.

Arthur Hannah FIAT President IAT


INSTITUTE UPDATE

Since the last issue, we have been working

on the following initiatives:

Your Details

We are working our way through some

holes and out of date information in

our database. We will be collecting the

information in a simple questionnaire

format, with few questions, to help us

ensure we focus on the actual requirements

of the membership. Your assistance with

this is appreciated.

Following on from this, applications in the

last couple of years had birth date omitted.

We will be looking to collect these, again so

we can gauge membership ages, to ensure

our output is relevant.

CPD Changes

As part of the branch event attendance

system, which was recently updated, the

delivery method of CPD certificates has

also been amended. In the past the member

would receive an email with the a link to

the CPD certificate. Now, the email will

advise that a new certificate has been

added to your account for viewing. It will

then be accessible via the membership

section of the website.

Institute Update - November 2013

Russell HunterBusiness and Development Manager

My contact details:

[email protected] 01506 238 397

Peer review of technical papersThe new editor reported in the last edition that

the intention was to make Asphalt Professional

a peer reviewed journal, but what does that mean?

The technical papers have been reviewed by a member of the

Technical Committee in the past, so what more is to be done?

The answer is that now it will be reviewed by three technical

experts, who may or may not be members of the Technical

Committee, using a standard review sheet. Those reviews will

be returned to the author(s) so that they can modify their

papers in line with the suggestions. The results should be that

the papers, when published, will be more authoritative but it

will take longer to get them published.

By moving to peer reviewing of the technical papers, we will:

n Give readers greater assurance of the technical relevance

of the papers.

n Give authors the kudos of publishing in a peer reviewed

journal (many organisations, including universities,

reward publication in peer reviewed journals)

This has the benefit of keeping all these

certificates in one place. You can log in

and view them at any time. It will also

track the amount of hours spent.

In addition to recording of our own events,

members will be able to add other activities

to their CPD list, enabling them to keep

a personal record of their time spent to

ensure they meet expected requirements.

Twitter Some changes have been made to the

Twitter account. As part of our events

system, technical evenings and social events

will be promoted with tweets 4 weeks,

7 days and then ‘Tonight!’, with event title

and link for more details and to register

your attendance. Please remember you

are welcome at events of all branches.

A member of Council, Ian Lancaster, has

kindly agreed to join the team making

posts. This shall ensure more regular and

spontaneous output that is worth catching.

So If you’re using Twitter, please do follow

us now to ensure you are kept abreast of

all the latest happenings @The_IAT

As always, please contact me with any

Institute related query.

EVENTS


Events www.instituteofasphalt.org/events

BRAnCH TECHnICAl AnD SOCIAl EVEnTS

Tuesday 12 November 2013 Scottish Branch Joint Meeting with The Institute of Quarrying new Thin Surfacings Alan Ferguson – Westerwood Hotel, 1 St Andrews Drive, Cumbernauld, Glasgow

Saturday 16 November 2013 western Branch 32nd Annual Dinner Dance The Bristol Hotel, Prince Street, Bristol

Thursday 21 November 2013 South East Branch Quiz night The Malborough Head, 24 North Audley Street London

Tuesday 3 December 2013 north East Branch The ramifications of High Modulus Base Bond Failures Professor John Knapton – Ramside Hall, Durham

Tuesday 21 January 2014 Scottish Branch EME2 A Scottish View Michael McHale – The Westerwood Hotel, 1 St Andrews Drive, Cumbernauld

Tuesday 21 January 2014 western Branch How low Can You go? Standardisation of Cool Asphalt Cliff Nicholls – Compass Inn, Tormarton, Badmington, South Gloucestershire

Tuesday 28 January 2014 north East Branch RAP Recycling Graeme Hall – Ramside Hall, Durham

Tuesday 11 February 2014 Scottish Branch AGM followed by The Falklands Runway Resurfacing - the Contractor’s View Brandi Davey – The Westerwood Hotel, 1 St Andrews Drive, Cumbernauld

Friday 7 March 2014 Scottish Branch IAT Scottish Branch Annual Dinner The Westerwood Hotel, 1 St Andrews Drive, Cumbernauld

Tuesday 11 March 2014 Scottish Branch Joint Meeting with The CIHT, North of Scotland Branch The Military Road Stuart Guthrie & Michael Gordon

Thursday 13 March 2014 western Branch Dam Asphalt - Hydraulic Asphalt Engineering for Dams, Reservoirs and landfill David Wilson – Fox & Hounds, Tytherington, Frome

OTHER EVEnTS

26-27 February, 2014 lJMu 13th International Conference Asphalt, Pavement Engineering and Infrastructure Liverpool, UK www.ljmu.ac.uk/BLT/BEST/LCMT/123156.htm

Thursday 19 June 2014 Scottish Branch The IAT national Conference- Bridging the gap Various – St Andrews University, St Andrews, Fife

INSTITUTE NEWS


INSTITUTE NEWS

Kurt started by showing some slides of

the condition of the bridge at the outset

of this Contract. These showed the existing

asphalt in a perilous condition. He was then

able to demonstrate using further graphic

slides how the asphalt had reached that

critical state. He explained that failure of a

bituminous surfacing is attributable to two

principle mechanisms: water penetration

and air penetration. The challenge was to

provide a surfacing, Gussaphalt, that was

impervious to air and water, smooth and

rut resistant.

Some of the factors considered in the

design of the surfacing were: Annual and

daily maximum and minimum temperature

variations, heavy goods vehicle frequency,

maximum axle loads and channelized

standing traffic loading, deck oscillations

and number of days at critically low

temperatures of less than 20ºC. Samples

of aggregate were taken from plant trials

at the quarry and combined to produce

a grading. Mix designs were completed

in Switzerland using the aggregate and

filler samples and bitumen from Scotland.

This talk was presented by Kurt Andres, CEO of Aeschlimann, and Adrian Pollitt, a Stirling Lloyd Representative.

The bitumen used was highly modified

elastomeric binder, Nynas Endura NS; this is

also the bitumen of choice of Aeschilmann

in Europe. Plant trials at Leith’s plant at

Achilty some 30 kilometres North of the

bridge were carried out and more samples

were taken for Type Approval Installation

Trials as demanded by Transport Scotland.

Additional samples were also taken for

laboratory testing in Switzerland.

Surfacing the Kessock BridgeTechnical Presentation – Scottish Branch – 10th September 2013

The material used for the Kessock Bridge

resurfacing is a Gussasphalt mastic asphalt.

This is a special mastic asphalt which relies

on the properties of the bitumen mixed

with crushed stone and limestone fines to

provide the stiffness and durability required

for a bridge running surface. Mastic asphalt

is impermeable to air and water, which

provides a longer service life for the mastic

because it is the permeation of water and

oxygen which causes the ageing process

of asphalt pavements.

Aeschlimann developed the mastic asphalt

for Kessock Bridge. It was produced at

Leith’s plant in accordance with Aeschlimann

specifications. Leith’s were supplying the

material from their quarry at Achilty which

is in Contin – about 16 miles North of the

bridge. The Gussaphalt was transported

in special delivery trucks which have the

ability to mix and heat the material.

The mix was laid by using a surface finishing

machine travelling on steel rails which

enabled the best regularity to be achieved.

Good smoothness provides better ride

comfort and reduces bridge movement

under load, thus extending the life of the

bridge. A 4/6mm chip was embedded in

the surface course material to provide some

surface texture.

Through his slides and by use of a sample

of material that was passed around the

audience, Kurt was able to show how the

Gussasphalt worked with the eliminator to

bond to the steel deck. Good preparation of

the deck was vital and the work could only

be carried out in dry conditions. The deck

was shot blasted and a primer was applied

before the application of two coats of the

eliminator. A tack coat was applied to the

eliminator which is heat activated by the

surfacing. Gussasphalt had been used with

Stirling Lloyd Eliminator on many occasions

in Europe and in England. The advantages

were that the complete structure was

impervious to water with both an excellent

laminate bond of all courses and a stable

pavement construction.

No 57 • SEPTEMBER 2013INSTITUTE NEWS


Paving machine

The paving machine travelled on steel rails which had been set up and levelled to provide

a uniform thickness and smooth riding surface. Regulating of some areas of the deck was

required and this was hand spread. Two layers – a binder and surface course – were laid

by paver. Each layer was laid continuously over an extended shift to avoid transverse joints.

A 2/6mm grit was coated with bitumen and rolled into the hot surface by a gritting box

and roller connected with the paving machine. A positive texture depth of 2.3 mm was

achieved and a GRIP number of 0.79 was recorded on completion of the surfacing.

Surface after chip embedment before Sweeping

Kurt concluded by saying that the use of Gussaphalt offered quality and sustainability in

the interests of the client, the public and the road user. His final slide showed the significant

benefit in terms of life cycle costs when compared with other conventional surfaces.

This presentation was very well received by about 50 people at our new venue,

the westerwood Hotel in Cumbernauld. The IAT Scottish branch is grateful to Kurt

and Adrian for a most interesting and informative presentation.


INSTITUTE NEWS

Scottish Branch Technical Presentation 19 February 2013Kevin Skinner of Scottish Water gave this presentation and he started off by saying

that the name of Scottish Water is like a poisoned chalice because people tend to think

regularity. The view of utility companies by the general public tends to be very poor

because they always seem to be causing disruption.

Kevin explained that he was on the working

group of four road authorities and four

utility companies who operate in Scotland.

The purpose of the group was to review

and update the existing reinstatement

specification to the third edition. The English

version of the specification is called SROH

and the Scottish version is called SROR,

the difference is because there are roads

in Scotland and highways in England. There

are different laws in Scotland which allow

the application of a specification to be more

progressive and innovative.

Kevin explained the SROR is a statutory

instrument for utilities which provides

consistency across Scotland, protecting

both the Authority and Utility and is written

as an agreement between the two parties.

A utility company needs access through

another body’s asset to carry out its work.

The specification within the SROR is drawn

from three main areas – the Design Manual

for Roads and Bridges, the specification for

Highway Works and application experience.

Kevin explained there are a number of

issues in producing a Statutory Code which

is comprised of Sections, Appendices and

Notes for Guidance.

The preamble to the new Specification (third

edition 2012) states that there is a strong

focus on sustainability by encouraging first

time completion, reuse and recycling of

materials. The Sections S1 and S2 set out

the general parameters associated with

reinstatements and expected performance

requirements. Kevin identified and discussed

some of the changes to these sections:

n The Guarantee Period is now two years,

or, in the case of deep openings, three

years. It is also the onus of the Undertaker

to provide evidence of the date of

completion of any given reinstatement

for liability guarantee purposes.

n As before, an Undertaker may adopt an

alternative Specification for materials.

Approval trials are now recorded centrally

in accordance with Appendix 9.6 of the

SROR.

n Unless specifically and reasonably

required by the road authority, all

aggregates used in surface courses will

have a PSV value of not less than 55.

n There is also a section that deals

with cracks that occur beyond the

reinstatement limits as a result of the

Undertaker’s work. The stepped joint

is also considered and, for deeper

excavation, no step is required between

surface course and binder course

although a minimum 75mm step should

be made between base and binder

course.

n Asphalt Concrete surface course materials

are to be AC 10 close surface, laid 40mm

thick. Where the asphalt concrete binder

course is to be used as a running surface

for a period in excess of 6 months, the

usual supplier declared binder content

shall be increased by 0.5%.

n There are also new requirements

for surface dressing.

Kevin explained that there was a

comprehensive set of notes for guidance

which had also been amended, some

of the examples are given below:

n The undertaker should require the supplier

of bituminous materials to regularly

supply details of the constituent materials

– in particular PSV/AAV test.

n The application rates for tack coating

materials are now given in kg/m2.

n There is also a section that deals with

water egress and the Authority shall

initiate an investigatory works procedure

to determine the cause and source of the

water egress.

n There is also a lot more information on

the use of SMAs and the point is made

that HAPAS approved materials may also

comply with HAUC requirements but there

is no guarantee. Some HAPAS materials

can have void contents in excess of that

permitted in this Specification.

n Alternative Reinstatement Materials

(ARMs), particularly slow cure

Hydraulically Bound Mixtures, may not

achieve their full design strength for

some time after placement. It is therefore

recommended that Structural Materials for

Reinstatement, used as subbase or base,

should achieve a minimum Immediate

Bearing Index (CBR without surcharge)

of 30 prior to overlaying and trafficking.

INSTITUTE NEWS


The Scottish Branch held its Annual Golf

Day on Tuesday 11 June at Alloa Golf Club,

Schawpark. Twenty one members and

guests turned out to play on an afternoon

of sunshine and showers. Thankfully

the heavy rain held off for most of the

time. The course, as always, was in good

condition and provided a tough challenge

for all competitors, despite the poor

weather much of the area has had

to contend with so far this year.

At the conclusion of the round, players

retired to the clubhouse to enjoy a very

fine high tea ahead of the prize-giving.

Despite the weather, scoring was still very

reasonable. The event was an individual

Stableford Competition with the usual

additional prizes for nearest the pin at the

four par three holes and a longest drive

at the seventeenth.

The winner on the afternoon was Scott

Edmondson of Aggregate Industries with

a very creditable 38 points. Graham Kerr

The SROR is a statutory instrument for utilities which provides consistency across Scotland protecting both the Authority and Utility and written as anagreement between the two parties.

Kevin explained that producing a code was a

difficult process, made even more complex

and time consuming by the committee

nature of the process. From the examples

he gave us, it is evident that this review

is extremely useful in achieving a better

quality of reinstatement.

Kevin identified possible future changes

and some of the main points that can be

considered:

n National coring/compliance changes

n Promotion on Appendix A9 trials for

ARMs and registering the products.

n Bevel joints.

n Resolution on guidance on where a

reinstatement becomes resurfacing.

n Better training.

n Long term damage.

Some Scottish water employees are

members of the IAT and has a very

positive role in the committee and

attendance of presentations. The

meeting was extremely well attended

and the Scottish Branch are grateful for

Kevin’s insight into the review of this

Specification.

of Lafarge Tarmac finished second with 35

points, beating Simon Parker of Nynas into

third place by virtue of a better back nine.

However as Simon was the highest placed

IAT member he was awarded the Eric

Boyd Trophy.

Longest Drive went to Robert McNaughton

of Hillhouse for a monstrous effort at the

seventeenth and nearest the pin prizes

were claimed by Gordon Hogg also of

Hillhouse, David Longmuir of Colas and Alan

Houston. Extra prizes were also awarded

for the best front and back nine. These

went to Dave Rennie of Leith’s and

Paul Torrance from the Colas team.

The Scottish Branch would like to thank

Graham Wright for all his efforts in

organising the day and extend a special

thank you to all the members and guests

who kindly supported the event. Last

but not least, thanks are also due to the

Companies who provided additional prizes

on the day. These were most appreciated.

IAT Scottish Branch Golf Outing


INSTITUTE NEWS

East Midlands Branch Report by Graeme Richards

to the future developments of SMA

throughout the world.

With the location of this technical evening

being close to the boundary of other branches

it was hoped this would appeal to a wider

audience geographically. Although numbers

were not as anticipated, those that attended

regarded the event as very worthwhile and

our thanks go to Horst and Steve Joyce from

Rettenmaier for hosting this.

October brought the East Midlands branch

to Mansfield for a technical evening at

J Rettenmaier & Son fibre factory, where

Viatop fibre is produced for the industry.

Horst Erdlen, Business Unit Manager for

the company, gave a most informative

presentation on Stone Mastic Asphalt which

took us back to the start of mastic asphalt,

through the pitfalls and best practice of SMA

production and installation requirements,

South East Branch

North East Branch

Get your thinking caps on, your brain

buzzing and take part in IAT Southeast

Branch ‘Quiz Night’. This is one of the most

eagerly awaited events of the year and

Southeast Branch would hate for you to

miss out!

Teams: 4 to 8 people per team. Entry & buffet

are free thanks to sponsorship by Nynas.

Note: To verify numbers for buffet –

please contact Steve Anstee at

[email protected]

if you will be attending this event.

Even the losers got a chance to win again

with the luckiest loser draw after each race!

The evening was split up with a tasty pie

and pea supper, followed by entertainment

from local comedian Zack Stevens.

Note that Zack had his eyes fixed firmly

on the PAYOUT, but security was never an

issue with Bob Bolden & Co looking after

the readies!

THuRSDAY 21ST nOVEMBER 2013

The Marlborough Head

(downstairs room)

24 North Audley Street

London, W1K 6WD

IAT SOuTHEAST BRAnCH

QuIz nIgHT

STARTIng AT 19:00

RACE nIgHT REPORT

Date: 11th October 2013

Venue: Ramside Hall Hotel, Durham

Resurrecting the race night event was

a huge success!!

Many thanks to Michael Atkinson for

co-ordinating the event, the whole

committee got roped in and we ended

up with a pretty rounded night out.

6 races to put our bets on…..

Mike and I sold the tickets with a little help

and lots of glamour supplied by Melanie

and Adriene

Packed ballroom zack Stevens

INSTITUTE NEWS


The presentation began with an outline

of the background of the background

of the Construction Products Directive

(CPD), implemented in 1989, and the

history of the way construction products,

particularly asphalt and aggregates, had

been voluntarily CE marked in UK from

2004 was. An important issue was that

previously, a member state could interpret

the requirements of the CPD, whereas

now, with the CPR, the regulation has to

be implemented verbatim without national

interpretation.

The most significant change resulting from

the full implementation of the CPR on 1st

July 2013 is that all construction products

supplied meeting the requirements of

either a harmonised European Standard

or the alternative and voluntary European

Technical Assessment have to be CE marked

to enable them to be legally placed on

the market!

The Basic Requirements for Construction

Works (BRCW) under the CPR were identified,

noting the addition of a new requirement

for Regulated Dangerous Substances (RDS)

under BRCW 3 and the new environmental

and sustainability requirements under BRCW

7. The meeting was advised that the testing

methods for RDS were still being considered

and that testing requirements and limits

are unlikely to be implemented until 2015

with the format of Environmental Product

Declarations probably not being finalised

until 2016/7. Changes in terminology were

outlined and such complex terms as the

‘Assessment and Verification of Constancy

of Performance’ (AVCP) – which rolls nicely

off the tongue – were explained along with

the various systems of AVCP that apply

to the different products. System 4 being

the least onerous with no involvement

of a Notified Body, rising to System 1

where third party assessment of the AVCP

documentation and its implementation

is required along with third party product

testing. Asphalt continues to be System 2+,

requiring the Notified Body to assess and

certify the AVCP system. However,

the manufacturer completes and issues

its Declarations of Performance (DoP) and

CE marking. Examples of products covered

under the various systems of AVCP were

identified.

The requirement in the CPR to affix CE

marking to the product, packaging, label

or accompanying documents was stressed,

noting that UK best practice applied since

2004 under the CPD had been to make

both the DoP and CE marking available

on company websites.

All construction products supplied meeting the requirements of either a harmonised European Standard or the alternative and voluntary European Technical Assessment have to be CE marked to enable them to be legally placed on the market!

The Cambridgeshire Trading Standards

Primary Authority Agreement was mentioned

which legitimises the use of company

websites for making DoPs available and

also permits electronic submission of CE

Western BranchREPORT On THE PRESEnTATIOn MADE BY JOHn B-BullOCK TO wESTERn BRAnCH On 26TH SEPTEMBER 2013 On THE COnSTRuCTIOn PRODuCTS REgulATIOn (CPR) AnD CE MARKIng John B-Bullock of Technical Asphalt and Asphalt Solutions and Technical Adviser to the

Mineral Products Association (MPA) gave a presentation on 26th September 2013 at

Tytherington near Frome on the Construction Products Regulation (CPR) and CE marking.

marking, e.g. by email, to accompany

commercial transactional documents.

However it was stressed that the agreement

does not legitimise the use of company

websites as the sole medium for making

CE marking information sheets available

to purchasers! Examples of DoPs and CE

marking information sheets were shown.

To conclude the presentation, the meeting

was advised that various useful documents

providing guidance on CPR and CE marking

are available to Mineral Products Association

(MPA) member companies through the MPA

Members website at:

http://members.mineralproducts.org/

user/web/index.php utilising a user name

and password, and information focussed

more towards customers and clients through

the MPA public website at:

http://www.mineralproducts.org/

prod_cpr_ce_marking01.htm

Noting the number of acronyms in use

with AVCP being a classic example, a

reference document containing over

460 such acronyms titled; ‘Acronym

Alley - your guide to industry acronyms’

was recommended. This document being

available on the MPA public website at:

http://www.mineralproducts.org/

news_publications01.htm

A number of questions were presented

and the IAT western Branch Chairman,

David walker, thanked the speaker

for his presentation and reminded the

meeting of the forthcoming branch

Technical events and the annual Dinner

Dance on the 16th november 2013.


INSTITUTE NEWS

In terms of bitumen testing, most countries

require the standard pen and softening

point tests for penetration grade bitumens.

But, with the increased use of polymer

modified bitumens, tests that are more

performance based and that assess the

rheological properties of the binder are

now being used more often. They include

DSR (Dynamic Shear Rheometer) and MSCR

(Multi-Strain Creep Rheometer) testing. The

Superpave approached that was developed

in the USA is now also being specified in

some European countries and includes

assessment of the long term aging (8+

years in service) of the binder using the

PAV (Pressure Aging Vessel) test. Sonia

also pointed out that Eurobitume and CEN

Technical Committee TC336/WG1 are about

to publish performance related specifications

for binders.

In terms of asphalt testing, Sonia outlined

the different approaches adopted in

Germany and France compared to Ireland

and the UK. In Germany, more focus is given

to testing the bitumen and using mixes with

high binder contents. Their philosophy is

that, if the bitumen is ok and there’s plenty

of it in the mix, then the mix will be ok. In

terms of asphalt mix testing, they use the

Marshall Test method, the Hamburg Wheel

Tracker and the Indirect Tensile Modulus

Test. In France, there is more of a focus on

testing the asphalt. Four levels of testing

are available, depending on the application

and level of performance required. A Level 1

assessment only requires Air Voids Content

and Water Sensitivity (Duriez) Testing. Level

2 requires Rut-Resistance Testing also. Level

3 requires the addition of Stiffness Modulus

Testing while Level 4 is required only for

the highest traffic loading applications and

included Fatigue Testing as a final measure.

Shell’s laboratory also perform all of the

standard UK tests including Wheel Tracking

to the BS test method, the Scuffing Test (TRL

176) and the TWIT test for assessing binder-

aggregate affinity.

Eurobitume and CEN Technical Committee TC336/WG1 are about to publish performance related specifications for binders.

In terms of trends in the asphalt industry,

Sonia described how warm-mix asphalts

are increasingly being used because of

their environmental and health and safety

benefits. Liquid additives (amines) can be

used to produce warm-mix asphalt that

gives a similar performance to hot-mix

asphalt. Waxes can be also be used and they

tend to produce warm-mix asphalt with

increased stiffness and increased resistance

to rutting. Shell has developed a third type

of warm-mix technology that involves the

use of foamed bitumen. The system, called

WAM-Foam, includes the use of RAP (with a

parallel drying drum), a bitumen rejuvenator

and wet dust (to foam the bitumen). Sonia

highlighted how one of the major benefits

of warm-mix asphalt is less binder aging

thanks to the lower mixing temperatures.

The bitumen does not drop by one grade,

due to oxidation during the mixing process,

as happens in the production of hot-mix

asphalt. The other major advantage with

warm-mix asphalt is that emissions are

significantly reduced: in fact, they are halved

for every 11°C drop in mixing temperatures.

At the end of her presentation, Alan

lowe, the newly elected Chairman of the

Irish Branch, thanked Sonia for her most

relevant and informative presentation.

Irish Branch Report by Tom Walsh PRO

On the 2nd of October, Sonia Hauguel, the Manager of Shell Bitumen’s European Solution

Centre gave a presentation to the Irish Branch at the Louis Fitzgerald Hotel, Dublin. The

presentation was entitled “European Testing of Bitumen and Asphalt: Differences and

Trends”. Sonia outlined the range of bitumen and asphalt tests that Shell perform in their

laboratory. Despite the introduction of harmonised European Standards for Asphalts in

2007 and Bitumens in 2009, there are still significant differences in the tests that are

being specified and conducted in each country.

IAT Vice President geraldine walsh, IAT Chairman Alan lowe and Sonia Hauguel, Shell


David then moved on to how tar had

been used in the 1950s to 1980s – from

grouting to surface dressing and fuel

resistant asphalt. In the late 1950s, of

the 1,000,000 tonnes of asphalt surfacing

produced, some 40% contained tar. Over

half a century later, this is presenting the

asphalt industry with some problems. One

of the problems faced by the industry is the

accurate determination of tar content, but

fortunately ADEPT has published guidance,

which is freely available via their website

(www.adept.net/research) .

The next part of David’s talk dealt with

the subject of scheme assessment and

how any excavated waste should be treated

as potentially hazardous. The final part of

David’s talk focussed on detection methods

and the options available to those finding

tar during construction and maintenance.

Thanks were expressed to the speaker and

all those who battled through the awful

traffic on the M6.

After a break for summer we resumed our

Technical Programme with a talk by Helen

Bailey (TRL) on “Use of Vegetable Oil in

Asphalt”. Helen explained the economic and

environmental benefits of her research and

then moved on to describe the fundamental

evaluation steps involved in taking the

initial concept to full-scale road trials.

One of the critical steps was to confirm

that the effects observed by blending

vegetable oil with bitumen would transfer

to asphalt mixtures. It was also important

that asphalt performance (stiffness, fatigue,

water sensitivity) were robust. Helen then

described the first site trials that were

carried out in 2009 and the difficulties that

were encountered with maintaining site

integrity during the “observations” of a

highly interested press corps. Finally Helen

explained how vegetable oils can be used

to rejuvenate asphalt planings and facilitate

more effective recycling.

In the late 1950s, of the 1,000,000 tonnes of asphalt surfacing produced, some 40% contained tar.

Our next Technical Evening is on 22nd

January 2014, and will feature Dennis

Day (Nynas) delivering a presentation

on “Cold Mix Technology”. We also hope

to incorporate a social event before the

end of the year.

All members of the Branch Committee

are very excited and honoured to be

given the opportunity to host the

2015 national Conference. If any of our

members would like to get involved in

organising this prestigious event, please

get in touch. Don’t forget to follow our

twitter feed (@IATPennines) and have a

look at our linkedIn page (IAT Pennines).

Stabilised Pavements LtdPO Box 6909, LutterworthLeicestershire, LE17 4WW

T: 01858 880499 F: 01858 881336E: [email protected]

www.roadrecycling.co.uk

ROAD RECYCLINGStabilised Pavements Ltd

AD RECYCLIN

EMISSION REDUCING

2CO SAVINGS

WITH IN-SITU

RECYCLING

StabilcourseDeep recycling

StabilhaunchHaunch recycling

TAR CONTAMINATED?

LOCK IT IN !

Pennines Branch Report by Ian Lancaster

The Pennines Branch has held two successful technical evenings

since our last report.

In May David O’Farrell gave an excellent talk on “Dealing

with Tar”. David gave a history of the use of tar in pavement

construction and explained the critical difference between tar

and bitumen. Specifically, David explained how the extremely

high temperatures used in the production of tar from coal lead

to the production of extremely high concentrations of polycyclic

aromatic hydrocarbons. This contrasts strongly with the production

of bitumen, where temperatures are very much lower.


CASE STUDY

Background of Reclamite Beginning in the mid 1950s, the

rejuvenator Reclamite® was developed

out of the work done by Dr. Fritz Rostler

and Richard White.

The interpretations of causes of aging

range from the assumption that bitumen

hardening and embrittlement is purely a

phenomenon of evaporation of the light

fractions, to more thorough explanations

predicated on the correlation of chemical

composition of bitumen to long-term

performance on the road. That is the inter-

relationship of the chemical fractions that

make up bitumen.

Bitumen consists of two main fractions;

“Asphaltenes” which are the hard brittle

component, insoluble and not affected

by oxidation, and the highly reactive sub-

fractions called “maltenes”. The maltenes

are oily and resinous in appearance

Rejuvenators need to be a fine particle-

sized, cationic, oil-in-water emulsion of

a selected blend of maltene components,

tailored to facilitate and assure the desired

mode of incorporation of the added maltene

fractions into an asphalt pavement.

Many features are considered and built

into the rejuvenator formulation, keeping in

mind that, after penetration of the emulsion

into the asphalt pavement, the essential

function is to deposit the blend of maltene

fractions onto the films of aged bitumen

without disturbing the existing structure

of the bitumen-aggregate mix with

respect to adhesion, cohesion or stability.

Of importance is that the deposited

maltene fractions must then flux with

the aged bitumen in place. Stability of the

emulsion, ease of handling and simplicity of

application are other significant objectives.

A cationic emulsification system is needed

which will penetrate rapidly into the pores

of the asphalt pavement, without displacing

the bitumen films from the aggregate or

destroying the existing structure of the

bitumen-aggregate mix.

In rejuvenator studies, different surfactant

technology has been tested as well as base

oil modification, but the fact remains that,

in order for a rejuvenator to penetrate, it

cannot be retarded by blending in a bitumen

emulsion or formulated into a quick dry

emulsion.

Once you stop the absorption, then you

lose the rejuvenation effectiveness. The

fact remains that, if the emulsion breaks

or cures on the pavement surface,

then it is sealing, not rejuvenating.

Details of norwich Trial The Internet research, as well as the

assurances given by the supplier, together

with a cost in line with market expectations,

was sufficient for Norfolk County Council

to consider undertaking a site trial.

The site at Daniels Road, Norwich had

been identified for surface dressing in

our programme. The existing surface is

Case Study on the Trial of Reclamite on the A140 Inner Ring Road Norwich Author Bob Noakes

Cl 942 Thin Surface Course and was installed

in 2006, it was showing some signs of

deterioration with some cracking from

underlying CBM bases, but overall is in a

good to moderate condition using TRL 674

descriptions.

The process is similar to a surface dressing

operation with a tanker application of the

emulsion through a rear mounted spraybar

and application of a fine aggregate prior

to opening to traffic almost immediately

following the break of the emulsion.

Therefore, it was easy enough to slot

the works into our programme.

Summary of site works 3rd October 2012

n Lane closure put on just after 9.30, 9.30

until 15.30 restrictions on road

n Sweeper turned up approx 10.15

n One sweep of the Newmarket bound

lane of the three coned lanes

n Gullys were then sealed

n Sweeper left area to park away from site

n Tanker then came to site at

approximately 11.00

n One full width and then one 3 jet widths

were sprayed on the road

n Material was allowed to soak in for

approximately 30 mins

n Tanker left site

n Gritter came to site

Introduction Norfolk County Council Highways Laboratory was contacted by a local supplier with regards to undertaking a trial of a rejuvenator

called Reclamite. Through work with the RSTA and ADEPT, the laboratory manager Bob Noakes is aware of surface applied treatments

to protect, maintain, improve asphalt pavements. Rejuvenators which can restore and improve asphalt properties offer great potential

in highway maintenance, if they actually work. Therefore Norfolk were keen to see if this process had some merit.

The laboratory manager undertook some googling prior to a meeting and discovered a wealth of data from the USA with many years

of successful applications as well as technical papers. The following technical information is based on a paper presented by Jim Brown-

ridge - Marketing Manager - Tricor Refining, LLC Bakersfield, California 93312 at ICPP April 2010 at Newport beach California entitled

”Role of Asphalt Rejuvenators in Pavement Preservation”. In USA pavement jargon, asphalt is bitumen and this has been changed to

enable UK pavement engineers’ easy reading.

CASE STUDY


n Gritter spread blast furnace bottom ash

on the road over the area which had

been sprayed.

n Additional grit was added near the

start of the rip due to excess amount

of solution on the road.

n Lane was open at approximately 12.15

n Centre lane was shut

n Same process carried out as above

n Less grit was used and spread at a better

rate the second time

n Process was completed faster

second time with the traffic swapped

over at approximately 13.30

n Process repeated for A140 direction lane

n All works were completed by 15.00

4th October 2012

n Site visit at 07:00, sweeper had just

completed site sweep

Discussion The results show that the existing asphalt

used included a Premium polymer modified

binder, most likely a high content SBS

elastomer. The Vialit curve closely resembles

results on bitumen used in asphalt on A143

Wortwell in 2003, which included Cariphalt.

The binder recovery process inevitably

homogenises the bitumen and the

subsequent tests are indicative. It is not

clear nor known whether the maltenes in

the Reclamite are in a separate phase to

the existing bitumen or whether they have

actually combined chemically. Does this

matter?

Conclusions The results indicate that penetration of the

rejuvenator has been to the full depth of

the layer. On a recovered binder sample the

results indicate the bitumen has reverted

to an as laid condition. Further trials will be

undertaken to establish if Reclamite has the

same effect on 40/60 pen binder and other

mixture types.

DETERMInATIOn OF COHEnSIOn OF BITuMInOuS BInDERS (VIAlIT PEnDuluM) EN13588-2008

RECOVERY OF BITuMEn – ROTARY EVAPORATOR (Including SP & Penetration) BS EN 12697-3:2005, BS EN 1427:2007 & BS EN 1426:2007

n Sweeper driver said that he hadn’t

removed much material from the road,

as not much there.

n Tried to skid to stop, but did not skid,

tried to wheel spin and did not wheel

spin.

Sampling and Testing In late January 2013, Sixteen 150mm cores

were cut from two different locations on

Daniels road, one set from the treated

section and the other untreated.

The surface course was cut into two 20mm

layers and all the 8 core layers combined to

give two test samples at each location. The

references being Existing Top and Bottom

and Treated Top and Bottom. This allowed

the testing to compare the treated and

existing untreated sections.

The bitumen was recovered from the

asphalt and tested for softening point

penetration and Vialit cohesion.

The results are shown below;

Existing top Penetration @ 25ºC 21 Softening Point ºC 63.6

Existing bottom Penetration @ 25ºC 26 Softening Point ºC 67.0

Treated top Penetration @ 25ºC 35 Softening Point ºC 58.0

Trial bottom Penetration @ 25ºC 38 Softening Point ºC 69.2

gOT An OPInIOn? we welcome your emails to:

[email protected]


TECHNICAL PAPER

1. Introduction

The use of Cold Bituminous Emulsion

Mixtures (CBEMs) for road construction,

rehabilitation and maintenance is gaining

interest day by day, as these mixtures offer

advantages over traditionally hot mixtures

in different terms such as environmental

impact, energy saving, cost effectiveness,

safer and cheap production processes.

In the UK today, the use of cold mix

generates less interest compared with Hot

Mix Asphalt, because these mixtures show

low earlier strength to resist the different

traffic loads and have low resistance to

water damage – especially rainfall. Other

countries such as USA, European countries,

and Australia showed more interest in the

uses of the materials due to the above

advantages.

Cold mix asphalt bituminous materials are

normally prepared at ambient temperatures.

In the UK, the use of

CBEM is largely restricted to surface

treatment such as surface dressing, slurry

surfacing and reinstatement work on low

trafficked carriageways and walkways

(HAUC, 1992; Read & Whiteoak, 2003),

due to the long curing time required for

such materials to reach their full strength

after paving, especially in the UK climate.

In addition, such mixes are highly sensitive

to rainfall at early life due to the high

voidage within the compacted mix.

Mechanical properties of CBEMs including

stiffness modulus, permanent deformation

and fatigue resistance, are affected by

many factors, including base binder grade

and characteristics, mixture void content,

curing time, aggregate characteristics and

additives (Needham, 1996; Thanaya, 2003).

Attempts to improve cold mix mechanical

properties have been investigated. An early

study (Head, 1974) indicated that Marshall

Stability of modified cold asphalt mix is

Hassan Al Nageim, Professor of Structural Engineering, Director of Studies, Head of Liverpool Centre for Materials Technology, School of Built Environment, Liverpool John Moores University, UK [email protected]

Shakir Al-Busaltan, LJMU PhD Graduate, School of Built Environment, Liverpool John Moores University, UK [email protected]

AbstractThis paper reports the stiffness, axial deformation and XRD analysis of a new cold mix asphalt developed for use in highway and

airfield pavement structural layers including surfacing pavement.

The main filler in the traditional cold bituminous emulsion mixtures (CBEMs) is replaced with treated biomass waste fly ash materials.

The waste or by-product materials were used as a modifier of the cold bitumen mixtures.

The new CBEMs have minimised the restriction imposed by road engineers on the use of cold bituminous emulsified mixtures

by improving its mechanical and durability properties and hence provided products that have the following advantages compared

with the traditional Hot Mix Asphalt (HMA);

i) less energy consumption,

ii) substantial reduction in CO2 emission and emission of pollutants, and

iii) saving in pavement total construction costs.

A treated biomass fly ash which is waste or by-product material was incorporated in the cold bituminous emulsion mixtures with five

percentages (0.0 to 5.5%) of aggregate weight in the mixture. The results have shown outstanding comparative improvement in the

mechanical properties of the new cold mixtures compared with traditional cold mix asphalt and HMA. The reason for achieving these

results is explained in this paper by the use of XRD (X-ray diffraction) analysis of the fine mineral-emulsified mortar used in this study.

Keywords: cold bitumen emulsion mixtures, waste material, stiffness modulus, creep stiffness.

Fast Curing Cold Mix Asphalt for Highways and Airfield Pavement

increased by 250-300% with the addition

of 1% Portland cement compared with un-

treated mix. Oruc et al., (2007) conducted

experiments to evaluate the mechanical

properties of emulsified asphalt mixtures

having 0-6% Portland cement. The test

results showed significant improvement

with high Portland cement addition;

moreover they suggested, based on their

study test results, that the cement modified

asphalt emulsion mixes might be used as

structural pavement layers.

Thanaya et al. (2009) showed that the

addition of 1-2 % rapid-setting cement

accelerates the earlier strength as well

as improves the mechanical performance

of the modified cold mixes.

TECHNICAL PAPER


The results have shown outstanding comparative improvement in the mechanical properties of the new cold mixtures compared with traditional cold mix asphalt and HMA.

Pouliot et al. (2003) conducted a study

with the aim of understanding the hydration

process, the microstructure and the

mechanical properties of mortars prepared

with a new mixed binder made of a cement

slurry and a small quantity of asphalt

emulsion (SS-1 and CSS-1, i.e. anionic and

cationic emulsion). They proved that the

presence of a small quantity of emulsion

had an effect on the cement hydration. Their

test results also indicated that the launch

of asphalt droplets inside a cement mortar

matrix leads to a considerable reduction

in the compressive strength and elastic

modulus in addition to a slight decrease in

the flexural strength. Also, they found that

the cationic emulsion (CSS-1), in contrast

with anionic emulsion (SS-1), shows higher

mortars strengths and elastic modulus.

Another study (Wang & Sha, 2010) indicated

that the increase of cement and mineral

filler fineness has a positive impact on

micro-hardness of the interface of aggregate

and cement emulsion mortar.

Research by Thanaya et al. (2006) indicated

that pulverised fly ash (PFA) can be used

as suitable filler in cold mixes at full curing

conditions. Also they found the stiffness of

cold mix achieved is very comparable to hot

mixtures.

From the above research works and other

attempts in the use of waste and by-

products materials to improve cold mixes,

four main benefits can be achieved when

utilizing the by-product materials on CBEMs.

These are:

i) Improving mechanical properties. In

general there will be an enhancement

of ultimate mechanical and strength

properties due to the cementitous

properties.

ii) Gaining economic benefit as the

pozzolanic and cementitous materials

used are mostly industrial by-products.

iii) Trapped water could be reacted with

these materials to complete the

hydration process. The result being

removal of this water which is the main

cause of increasing the curing period

in CMAs.

iv) The ecological benefit factor.

The central theme of this work reported

here concentrated on the use of biomass

treated fly ash as filler in cold bitumen

emulsion mixtures to overcome the

following shortcomings of cold mix,

namely low early stage mechanical

strength, high void contents and long-curing

time, which may take from 2 to 12 months.

Biomass fly ash incorporated as filler in

Test sieve aperture

size mm

% by mass passing

specification range

% by mass passing mid

14 100 100

10 95-100 97.5

6.3 55-75 65

2 19-37 28

1 10-30 20

0.063 3-8 5.5

Properties Value

Coarse aggregate

Bulk specific gravity, Mg/m3 2.79

Apparent specific gravity, Mg/m3 2.82

Water absorption % 0.4

Fine aggregate

Bulk specific gravity, Mg/m3 2.74

Apparent specific gravity, Mg/m3 2.77

Water absorption % 0.4

Table 1: Aggregate grading for 0/10 mm size close graded surface course BS EN 13108-1

Table 2: Physical properties of aggregates

CBEMs in this study at a percentage of

replacing filler from 0.0 to 5.5% of the

aggregate weight. The improvement in

mechanical properties, determined using

the indirect tensile stiffness modulus

and unaxial compressive cyclic test, was

explained by using XRD analysis to provide

an understanding of the early stage stiffness

and strength developments.

2. Materials and sample preparation method

2.1 Materials

In order to ensure appropriate interlocking

between cold mix asphalt ingredient and

to provide high surface strength pavement

layer, 0/10 mm Close graded surface course

with mix gradation according to BS EN

13108-1 was selected for this research work.

The aggregate used in this study is crushed

green granite from Cliffe Hill quarry and

the aggregate gradation is given in Table

1. Physical properties of the aggregates

are given in Table 2. The aggregate was

dried, riffled and bagged with sieve analysis

carried out according to BS EN 933-1 and BS

EN 932-2. The grading of the 0/10 mm mix

is shown in Figure 1.


TECHNICAL PAPER

The selection of this gradation was

completed with consultation of our industrial

partners and based on, firstly, that this

gradation has been used successfully in the

heavy traffic surface coarse asphalt concrete

(BS EN 13108-1) and, secondly, the dense

gradation has a higher percentage of coarse

aggregate particles compared with close

graded hot mix coated macadam, (Doyle

et al., 2010) and not easily compacted.

Cationic slow setting bituminous emulsion

C 60 B 7 to BS 434-1:2011 was used in the

experimental programme to ensure high

adhesion between aggregate particles.

Table 3 shows the properties of the

selected emulsion.

2.2 Sample preparation

All samples produced for this study were

prepared according to the method adopted

by the Asphalt Institute (Marshall Method

for Emulsified Asphalt Aggregate Cold

Mixture Design) (MS-14, 1989). According

to the selected materials characteristics,

pre-wetting water content was observed to

be 4%, the optimum bitumen emulsion was

11.5% and optimum total liquid content at

compaction was 14.5%.

2.3 Sample conditioning

Cold mixture strength characteristics

are very sensitive to curing time and

temperature. Therefore, sample conditioning

for indirect tensile test was carried out

in two stages; stage one with 20ºC for

24 hours as the sample needs to be left

in the mould before extruded to prevent

specimen disintegration. Second stage

conditioning was achieved with three curing

temperatures (20, 40, 60ºC) and tested at

age of 2, 7, 14, 28, 90 and 180 days. The

selections of two stage sample conditioning

criteria was based on the past curing criteria

adopted by various researchers, see Jenkins

(2000)

3. Testing, results and discussion3.1 Indirect Tensile Stiffness Modulus

The Indirect Tensile Stiffness Modulus

(ITSM) is a non- destructive test used

mainly to evaluate the stiffness modulus

of hot mix asphalt. ITSM at 20°C was used

to evaluate the effect of the new filler on

stiffness modulus. The test was conducted

in accordance with BS EN 12697-26:2004

Annex C, using the Cooper Research

Technology HYD 25 testing apparatus,

Figure 2. The test conditions as in Table 4.

Specimens of cold bitumen emulsion

mixtures were prepared using different

ratios of biomass treated fly ash (0.0 -

5.5%) as a replacement of mineral filler.

All mineral filler comes from Cliffe Hill

aggregates. Impact compaction (Marshall

Hammer) was applied with 50 blows to

each face of the specimens. Moreover,

conventional hot mixture samples were

prepared with the same aggregate type,

same aggregate gradation and with 5.3%

binder content to match the BS EN 13108-1

0/10 mm size close graded surface course

mixture. Both cold and hot mixes were

prepared in quantity to produce three

1100 g specimens for each specific mix.

The cold mix specimens were mixed and

compacted at lab temperature (20 - 25°C),

while hot mix specimens were compacted

at 135-140°C.

Properties Value

Appearance Black to dark brown liquid

Boiling Point (º C) 100

PH 5

Residue by distillation (%) 56Figure 2: HYD 25 testing apparatus

Table 3: Bitumen Emulsion Properties

Figure 1: Grading 0/10 mm aggregate

TECHNICAL PAPER


3.2 Results and Discussion

3.2.1 Indirect Tensile Stiffness Modulus

(ITSM)

All cold bitumen emulsion mixture specimens

for the ITSM test were tested at age of

2,7,14, 28, 90 and 180 days. The first curing

time was 24 hours at 20ºC, then 24 hours

curing at three curing temperatures (20,

40 and 60ºC) in order to identify the effect

of replacing mineral filler with the newer

filler, treated biomass fly ash (TBFA), on the

mixture’s hydration mechanism and thus on

the improvement in ITSM strength. The results

of these tests are shown in Figures 3 to 5.

Results of ITSM tests shown in Figure 3,

indicate that the stiffness modulus of CBEMs

increased dramatically with the increased

percentage of the replacement filler, and

reached its ultimate values when all the

mineral filler was replaced with the new

filler. Additionally, the ITSM increased

significantly with time.

An outstanding gain in ITSM values was

experienced at the other curing methods

(i.e. stage two with 40 and 60ºC) with the

increase in curing time and TBFA percentage,

Figures 4 & 5. At the same time the HMA

showed unnoticeable changes in ITSM with

time. Hot Mix Asphalt was made from the

same mix gradation in Table 1 with 100/150

pen and 40/60 pen to represent both soft

and hard binders commonly in use. With no

or low percentage of the replacement filler,

no results after two days are shown in Figure

3 as the specimens could not withstand the

testing load.

Item Range

Specimen diameter (mm) 100±3

Rise time (ms) 124±4

Transient peak horizontal deformation (µm) 5

Loading time (s) 3-300

Poisson’s ratio 0.35

No. of conditioning pulses 10

No. of test pulses 5

Test temperature (°C) 20 ±0.5

Specimen thickness (mm) 63±3

Impact compaction (blows) 50×2

Specimen temp. conditioning 4h before testing

Table 4: ITSM Test Conditions

Figure 3: ISTM (MPa) of cold mix asphalt

Figure 4: Effect of TBFA % on ITSM (24h, 20 0C + 24 h. 40 0C)

Figure 5: Effect of TBFA % on ITSM (24h, 20 0C + 24 h. 60 0C)


TECHNICAL PAPER

Figure 6 shows the final conditions of

control and specimens containing the new

replacement filler. The control specimens

were made from the same materials used to

produce CBEMs but with 5.5% mineral filler

from Cliffe Hill aggregate. Control specimens

show a total collapse, where the specimen

with 5.5% replacing filler (complete filler

replacement) does not show any sign of

collapse. However, specimen with 2.5%

TBFA showed a partial sign of collapse.

3.2.2 Microanalysis of CM-TBFA -

XRD analysis

Figures 7 (a-e) demonstrate the XRD patterns

of powder produced from CM and TBFA

mastic which analysed after 2, 7, 14 and 28

days of curing, respectively. The results of

these figures indicate the following:

n The crystalline components of the blend

powder are Quartz (SiO2) feldspar

Microcline (K0.92

Na0.08

Al0.99

Si3.01

O8),

Kaolinite (Al2 Si

2 O

5(OH)

4), Lime (CaO),

Mayenite (Ca12

Al14

O33

), Calcite (CaCO3),

Gehlenite (Ca2Al

2Si

O7) as can be seen in

Figure 7 (a). The first three components

represent CMF phases, while the rest

represent TBMFA crystalline phases.

n TBFA phases showed significant changes

with time due to mix with bitumen

emulsion and water. Some phases were

released either completely at early age

like Lime, or with time like Mayenite

and Gehlenite which took more time.

Simultaneously, Portlandite (Ca(OH)2)

and Hydrotalicte ((Mg4Al

2)(OH)

12(CO

3)

(H2O)

3)

0.5) appeared progressively, and

the Calcite (CaCO3) increased, obviously,

as can be seen in Figures 6 (b to e)

Figure 6: The final conditions of control and TBFA specimens

a

b

c

Hot Mix 100/150 pen

Cold Mix 5.5 % TBFA

Cold Mix 2.5% TBFA

Control Cold Mix

The appearance of Portlandite and

Hydrotalicte give the evidence of hydration

process, which in turn prove that TBFA is

a hydraulic material not pozzolanic, and

its continuous reaction with water and

production of hydration products are the

main reason for the strength increase of

the new cold mix asphalt developed in

this research work. Hydraulic material is

a material chemically reactive with water

that leads to setting and hardening of the

material whereas the existence of pozzolanic

materials within the TBFA such as silica fine

particles act as filler to reduce the space

between the cement particles and resulting

in a much denser binder.

TECHNICAL PAPER


d

e

Figure 7: XRD patterns of TBFA -CMF powder (a) and CM-TBFA mastics (b-e)

4. Conclusions1. This experimental study has focused on

studying the effect of the treated biomass

fly ash on improving the engineering

properties of close graded surface course

Cold Bitumen Emulsion mixtures (CBEMs)

in terms of stiffness modulus.

2. Previous research works have shown

that adding cementitious fine materials

such as Ordinary Portland Cement,

Rapid Setting Cement (high early

strength cement) or CBEMs have shown

successfully improvement in engineering

properties of CBEMs. Unfortunately these

materials have a significant carbon

footprint, and are not cost effective.

Whereas current study concentrates

on the use of waste materials with

significant low or non carbon footprint.

3. The test results confirmed that there is a

significant improvement in the stiffness

modulus with the use of TBFA, especially

when 50% or more of the mineral filler

is replaced with TBFA. More than 9 times

the value of the traditional cold mix (non-

treated mixtures) stiffness was achieved

when all the mineral filler (i.e. 5.5%)

was replaced with TBFA. Furthermore,

the result showed that cold mix stiffness

modulus achieved is more than the HMA

after 14 day at 20°C curing. On the other

hand, it was clearly shown that the curing

temperatures played a considerable

influence on stiffness modulus values.

4. The improvements in stiffness modulus

due to the use of TBFA were due to two

valuable materials characteristics. Firstly,

the new filler has a high absorptive ability

for water which is obviously shown during

mixtures preparation process especially in

mixing. This property didn’t affect coating

of the aggregates with emulsion. Secondly,

the new filler’s cementitious property

which was clearly shown through the

increment in the stiffness modulus with

time of curing at all curing temperatures.

5. The aggregate used in this study is

crushed green granite from Cliffe Hill

quarry. The authors would anticipate

that the results would be the same for

limestone aggregate. This is currently

under investigation at our laboratory.

Acknowledgements

The Authors wish to thank both Dr. linda

Seaton and Dr. nicola Dempster of the

School of Chemistry and Bimolecular

Sciences, lJMu, for their continuous

support throughout this study.

ReferencesComité Européen de Normalisation (1997).

BS EN 933: Part 1.Test for Geometrical

Properties of Aggregate-Determination of

partical size distribution-sieving method.

British Standards Institution London,UK.

British Standard Institution (2005). BS

EN 13108-1: Coated macadam (asphalt

concrete) for roads and other paved areas:

Specification for constituent materials and

for mixtures. British Standards Institution

London,UK.

British Standard Institution(2001). BS EN

12697:Part 28.Bitumenous Mixtures-Test

Methods for Hot Mix Asphalt- Preparation

of Samples for Determine Binder Content,

Water Content and Grading. British

Standards Institution London, UK.

BS EN 932-2:1999 Tests for general

properties of aggregates. Methods for

reducing laboratory samples and BS

434-1:2011 Bitumen road emulsions.

Specification for anionic bitumen road

emulsions

Doyle, T., Gibney, A., McNally, C., &

Tabakovic’, A. (2010). Developing

Spesifications for Cold-mix Pavement

Materials. Submitted to Transport

Research ArenaEurope.

Head, R. W. (1974). An informal report of

cold mix research using emulsified asphalt

as a binder. Association of Asphalt Paving

Technologists Proceeding(AAPT), Vol.43,

pp. 110-131.


TECHNICAL PAPER

Highway Authority and Utility Committee,

(1992). New Roads and street works Act

1991- Specification for the reinstatement

of opening in highways,. HMSO, London.

Asphalt Institute (1989). Asphalt Cold Mix

Manual, manual series No.14 (MS-14)

(3rd ed.). USA.

Jerkins, K. (2000). Mix design considerations

for cold and half-warm bitumious mixes

with emphasis on foamed asphalt.

PhD thesis, university of Stellenbosch,

South Africa.

Needham, D. (1996). Developments

in Bitumen Emulsion Mixtures for Roads.

Ph D thesis . University of Nottingham.

Oruc, S., Celik, F., & Akpinar, V. (2007).

Effect Of Cement On Emulsified Asphalt

Mixtures. Journal of Materials Engineering

and Performance, Vol.16(5), PP.578-583.

Pouliot, N., Marchan, J. d., & Pigeon,

M. ( 2003). Hydration Mechanisms,

Microstructure, and Mechanical Properties of

Mortars Prepared with Mixed Binder Cement

Slurry-Asphalt Emulsion. Journal of Materials

in Civil Engineering, Vol. 15,No. 1, pp. 54-59.

Read, J., & Whiteoak, D. (2003). The Shell

Bitumen Handbook. (S. U. products, Ed.)

1 Heron Quay, London.: Thomas Telford

Publishing.

Thanaya, I. (2003). Improving The

Performance Of Cold Bituminous Emulsion

Mixtures Incorporating Waste Materials.

PhD thesis. The University of Leeds.

Thanaya, I., Forth, P., & &Zoorob, S. (2006).

utilisation of coal ashes in hot and on cold

bituminous mixtures. International Coal

Ash Technology conference, Paper ref.A9.

Birmingham, UK.

Thanaya, I., Zoorob, S., & Forth, P. ( 2009).

A laboratory study on cold-mix, cold-lay

emulsion mixtures. Proceedings of the

Institution of Civil Engineers, Transport 162,

pp.47-55.

Wang, Z., & Sha, A. (2010). Micro hardness

of interface between cement asphalt

emulsion mastics and aggregates. Materials

and Structures, vol.43, pp.453–461.

REVIEWS

Review of TRL Report PPR666 Report by Stephen Child

n Standard specification for half-warm

mix asphalt

n Standard specification for emulsion-based

cold mix asphalt

n Aggregate grading of reclaimed asphalt

n Example standard specification for half-

warm asphalt concrete

n Example of standard specification for

half-warm hot rolled asphalt

n Example of standard specification for

half-warm stone mastic asphalt

n Example specification for emulsion-based

cold mix asphalt

n Specification requirements for low

temperature asphalt mixtures

n Notes for Guidance on specification

requirements for low temperature

asphalt mixtures

The Appendices are similar to the current

European Standards, supporting National

Guidance documents and the SHW clauses.

The final paragraph of the report states that

“It is intended that the availability of these

Specification for low Temperature Asphalt Mixtures

This report does exactly what the title

suggests and provides specifications and

guidance for various low temperature

asphalt mixtures. The main text of this 68

page report is only 12 pages; however, this

nugget gives the background on the need for

such materials to support sustainability and

the reduction of the carbon footprint. There

are a both very informative schematic and

descriptions showing the differences between

cold, half-warm, warm and hot mix asphalt.

The report then describes the current situation

regarding specifications which are primarily

based on BSEN1308 for hot mix asphalt.

The appendices provide the majority of the

text and the reader can utilise any of the

following example documents:

n Standard specification for warm mix

asphalt

documents will allow warm mix asphalt,

half-warm asphalt and emulsion-based

cold-mix asphalt to be procured and that

feedback from their use will help to develop

the European and national documents

that will replace them in due course”. All

practitioners within industry, particularly

members of the IAT, have the opportunity to

encourage greater use of low temperature

asphalt mixtures until the relevant standards

are developed. In doing so it is essential,

as with current material specifications, that

competent personnel review such documents

and, when appropriate, specify requirements

that are needed for performance. As we

seek to manage the asset in these difficult

times we need to remember our role and

responsibility for a sustainable future.

Author JC Nicholls (TRL), HK Bailey (TRL),

N Ghazireh (Lafarge Tarmac)

and DH Day (Nynas)

Pages 68

Reference PPR 666

Contracting+ Materials

AGGREGATESGritstone / Greywacke +68 PSVGritstone / Greywacke +65 PSVBasalt AggregatesSub-Bases

High Specification Aggregatesfor the UK and Ireland

With quarrying operations dating back over 50 years, we are a leader in our chosen markets and our quality aggregates are used by the major asphalt manufacturers across highway construction and civil engineering projects. All aggregates are produced in accordance with European Standards with our quarries and products holding relevant CE Marking and Type Test Certifications.

MATERIALSAggregatesAsphaltBitumenSpecial Products

CONTRACTINGAirfieldsCivil EngineeringHighwaysInert Waste

T: +44 (0) 28 9250 1000E: [email protected]


CONFERENCE REPORT

Details of the specification clauses can be

found in Published Project Report PPR666

on the TRL website www.trl.co.uk by

searching “PPR666”. It’s free of charge.

The Conference consisted of 12

presentations, and whilst the main and key

theme was the warm asphalt itself, there

was a very strong subtext around innovation

and how to move from an innovative idea

to implementation.

Donna James’ presentation set the scene

for innovation, informing the audience that

the Highways Agency sets out to “make

innovation integral to everything we do

in search of sustainable solutions”. Donna

went on to indicate that Warm mix asphalt

has passed the first two stages in the HA

“4D – phased approach” to implementing

innovation. It has demonstrated that it is

available through small scale trials, and it

meets the requirements of the design risk

assessment tool. That leaves the need to

develop a programme of larger scale trials,

which needs to be followed by the delivery

of full scale schemes. Donna helpfully

described the procedure used by HA to

assess risk in which the total risk is the

product of confidence (in the technology)

and the potential consequence. By way of

additional explanation, the “consequence”

is the product of the difficulty to remediate

a failure and the volume of traffic that

will be disrupted. Finally Donna told the

audience that the HA was actively looking

for sites for trials – perhaps by now there

are some strong candidates.

Malcolm Simms, Technical Director at the

Mineral Products Association, summarised

work presented at the European Asphalt

Pavement Association (EAPA) which took

place in Istanbul, Turkey in 2012 and at

the EAPA General Assembly in Tallinn,

Estonia in June 2013. EAPA has helpfully

provided the following set of definitions

so that conversations and debates have

some common boundaries:

Hot Mix

Produced and mixed at temperatures

roughly between 140°C and 190°C.

warm Mix

Produced and mixed at temperatures

roughly between 100°C and 140°C.

Half warm Mix

Produced with heated aggregate at a mixing

temperature between approximately 70°C

and 100°C.

Cold Mix

Produced with unheated aggregate and

bitumen emulsion or foamed bitumen.

nATIOnAl MOTORCYClE MuSEuM. 20 JunE 2013 Introduction to the ConferenceThe driver for the conference is the need to make reductions in energy consumption and carbon emissions in order to meet sustain-

ability targets deemed appropriate for the future wellbeing of the environment. A collaborative project, led by Lafarge Tarmac, and run

as part of the Industrial Energy Efficiency Accelerator Program, provided much of the information for the presentations that were given,

(other original partners were Nynas, Atkins and Miro with TRL replacing Atkins for the second phase) and there was input from a large

number of local authorities. The primary aim of the conference was to make the Industry aware of the draft clauses that have been

developed for European Standards, National Guidance documents and the National Specification, with the associated notes for guidance,

for low temperature Asphalt. The conference was part of the “The Sustainability Breakthrough Series” overseen by the Carbon Trust.

Low Temperature Asphalt Report by Dr A F Stock

Focus Objective Technology

Binder Additives Alter bitumen viscosity Organic waxes

Compaction aids Anhydrous chemical surfactants

Mix Additives Alter mix viscosity Chemical foaming agents

Compaction aids

Viscosity modifiers

Process Modification N/A Utilisation of water and foaming bitumen

Warm mix asphalt has passed the first two stages in the HA “4D – phased approach” to implementing innovation.

It is not surprising to find that the initiatives

across Europe utilise a number of different

technologies, and that the drivers are

different. One common question relates to

identifying tests that are appropriate for the

evaluation of innovative technologies, and

will be accepted as helping to demonstrate

low risk in the HA risk assessment

procedure. The conventional approach

of full scale trials is very expensive, very

limited and very time consuming. Malcolm

suggested a trial of three technologies, Cold

(Emulsion), Foam, and Chemical Additive,

against a conventional Hot Mix Asphalt

system, focusing on the binder and surface

courses.

Dennis Day provided an overview of the

technologies currently being promoted

to reduce temperatures in paving. Those

related to warm and half warm mixes

are summarised in the table below.

Dennis summarised the results of testing

in the UK as follows:

n Retained stiffness similar to hot mix

equivalent material

n Stiffness comparable to equivalent

hot mix material

n Binder ageing on mixing less than

equivalent hot mix material

n Wheel-tracking results comparable

to hot mix material

n Voids similar to equivalent hot materials.

Dennis also raised the question of

whether innovation should be judged

on the basis of “cost reduction” or “value

added” as judgements based purely on

“cost reduction” have obvious negative

connotations when additives are part

of the innovation.

It is not surprising to find that the initiatives across Europe utilise a number of different technologies, and that the drivers are different.

Mr Ian Waddell, managing director of

Tayside Contracts, briefed the audience on

“Tayset”, a cold mix product containing

approximately 65% reclaimed materials

developed to be suitable for use in Scotland.

The product was developed through a

Knowledge Transfer Partnership involving

the University of Dundee and Tayside

Contracts with input from the bitumen

supplier Nynas. The results of stiffness

tests carried out at 10ºC show significant

development of stiffness with time, with

values in the range of 5000MPa to 6000MPa

being obtained after 180 days. Three trials

were described, the first being as a base

layer in a Park and Ride area in Stirling in

which 530 tonnes of Tayset was laid with

a saving of 12,000 kg of CO2. The second

project was on the A90 between Snabs and

Star Farm in which 1600 tonnes was laid

as a base leading to a saving of 43 tonnes

of CO2 emissions. The final trial was on a

road in Central Scotland when Tayset was

placed as the surface layer and then surface

dressed immediately. This latter project is

very similar to the “Retread” process which

has been available for quite a few years.

Detailed information on performance was

not presented.

Mr Jonathan Tamblin from Gloucestershire

Highways shared some very valuable

experience of using cold mix processes

to process arisings containing tar into

useable paving material for very low traffic

volume rural roads. One great advantage

of the process is that it complies with the

900 series clauses in the HA specification

documents and that it contains very little,

if any, new aggregate. There are a number

of very helpful practical observations with

respect to the cold mix as follows:

n It is best laid 80mm thick, on sites

with retained edges for binder courses.

n It remains mobile for some time after

laying as it has a “setting” phase

n It has a certain self healing property as it

is less brittle than conventional blacktop

and can be laid over cracked surfaces

as reflective cracking is reduced by the

material.

n It can be laid on unrestrained sites but

verge make up would be expensive.

n It is a water-based emulsion product

and should be laid in dry conditions

with temperatures well above freezing.

n Laying under trees is not ideal as the

product takes longer to set when

sheltered

n It likes a PTR roller to lay it

n A 20mm binder course material for

use on minor roads has been trialled

n A 20mm deferred set material has

been developed for use in potholes

n Cold mix can be used as a binder in

footways, and also as a binder in

haunching and patching, however

a surface course will be required

Having satisfied themselves that satisfactory

binder course materials can be produced,

the next phase for Gloucestershire Highways

is to develop a 14mm surface course.

Mr Brian Kent, the National Technical

Director at Lafarge Tarmac, described how

a supplier looks at Warm Mix development.

The first important issue is to understand the

client driver, and the importance of making

good decisions, which he explained by using

an analogy with football management,

where the consequences of managers

making incorrect decisions are very obvious

and well known. Brian demonstrated an

analysis of the “Warm” and “Cold” processes

for producing asphalt against four criteria:

n Embedded carbon at the gate

n Set-up cost

n Running cost

n Heating and drying fuel usage

This analysis showed very clearly that there

was no single process that came out on top

against all criteria, which adds significantly

to the complexity of decisions relating to

investment in plant and technology and

emphasises the need for engagement

between Client and Supplier. In this respect

the following points are significant:

n Clarity with respect to client priorities

will assist investment decisions

n The level of demand for low

temperature asphalts will determine the

level of investment from suppliers, and

consistency of daily production demand

is essential before any potential cost

savings can be obtained.

n The specification will not dictate ‘how’

to make LTA

n Clients should engage with supplier(s)

so that they can understand how best

to meet needs / priorities

CONFERENCE REPORT



CONFERENCE REPORT

Dr Mike Gibb of Hyperion Infrastructure

Consultancy made a presentation on

behalf of Atkins on Perceptions and Barriers

to Uptake. This was a very interesting

presentation as it reported on a project

designed to find out, primarily by engaging

with highway authorities but including

consultants and contractors, what barriers

exist with respect to the implementation of

warm mix asphalt solutions. It has provided

significant insights which probably have

relevance to innovation as a whole. It was

carried out in two phases, the first designed

to identify barriers, and the second to

develop understanding of the blockers and

to develop practical measures to overcome

them. In order to provide a framework for

the study, four key sectors within which

barriers could be defined were identified.

These are;

n Cultural

n Perception

n Organisational

n Technical

A scoring system was developed so that

specific barriers could be ranked, and also

so that the relative importance of the four

sectors could be assessed. The study showed

that the sectorial boundaries, in order of

significance, are:

n Technical

n Perception

n Cultural

n Organisational

Within the Technical sector, again in order

of severity, the barriers, all with high scores,

are:

n Knowledge and Understanding

n Guidance

n Specification

n Specialist impartial assistance

Within the Perception sector the barriers,

with the first two rating well above the

other three, are;

n Evidence of performance

n Affordability

n Personal views

n Benefits unclear

n Proprietary processes

Within the Cultural sector the barriers have

similar rankings, but in order they are;

n Engineering skills

n Confidence in success

n Attitude to risk

n Absence of established advocacy

n Priority for attention

Within the Organisational sector the barriers

are closely matched and are close to neutral,

in order they are;

n Regulator approval

n Key action drivers

n Leadership views

n Procurement

n Logistical planning

n Organisational structure

None of the organisational barriers

came within the top ten barriers overall.

The second part of the study started with

the objective of understanding the reason

for the popularity of existing hot mix asphalt

and discovered the following:

It was discovered that while 75% of

participants would consider a lower carbon

foot print product with similar properties

to a hot-mix, as listed in the table above,

only 42% would consider its use in a

surface course.

It can be argued that this conference is one of the most important held during the year, or even in recent years, because it focuses on a significant innovation being made available within the paving industry, and one which addresses the priorities of the Government based client.

The sessions to explore and overcome

key barriers led to the following outcomes.

general appeal Requirements for base/

binder layer

Requirements for surface

course

Familiarity Durability Skid resistance and texture

Proven performance Stiffness Durability

Forgiving/repairable Impermeability Ride quality

Availability Deformation resistance Deformation resistance

Investment value

CONFERENCE REPORT


The final general findings were;

Skills base

n Concerns that in future the highway

engineering profession is likely to

become more “general” with even

less specialist expertise.

n This will impact upon the depth of

understanding, particularly in client and

procurement sectors, and the confidence

and appetite to embrace and accept new

technologies.

uptake and implementation

n Difficult experiences of modifications

to imported asphalt technologies for

UK highway environment.

n Concern that this could recur; must be

addressed in design and application

from a risk and durability point of view

for UK conditions.

Dr Nizar Ghazireh, Senior Manager – R & D,

Lafarge Tarmac, described the Specification

Trials undertaken as part of the Industry

Energy Efficiency Programme. The trial

consisted of ten 75m long sections in which

“Half-Warm” and “Cold” binder course

layers were trialled with Half-Warm and

conventional hot mix surfaces. The trial

was built on an Unclassified Road with

traffic loading up to 0.5 msa in 2011.

Cores extracted from the trial showed well

compacted layers. ITSM measurements on

the cores from the surfacing layer at 11 and

64 weeks were reported together with Light

Weight Deflectometer determined surface

modulus values after installation. The trial

has demonstrated that both half warm and

cold mixes can be laid successfully and has

contributed to the first draft of specification

clauses. It is planned for this trial to be

monitored and for further tests to be

carried out.

The project is not complete and Dr Ghazireh

indicated that the next stage is to undertake

a validation trial, in accordance with

the developed specifications, which will

hopefully be co-ordinated with the HA

trials which Donna James mentioned. The

validation trial will trigger a review of the

draft specification, which will be undertaken

in consultation with the Industry to iron out

any issues identified in relation to the use

of the specification.

One more task within the project is to

develop case studies with the Carbon Trust,

which should help to deal with some of

the barriers identified in Dr. Mike Gibb’s

presentation.

Dr Cliff Nicholls, Senior Academy Fellow

at the TRL, gave the presentation of the

specification as developed to date. He

started by reminding the audience that

there are various levels of specification,

with the European Standard at the top

of the hierarchy, followed by National

Guidance, National Specification and finally

the Job Specification. It was indicated that

having considered preparing standalone

specifications, the preferred option is to

modify existing documents to include the

categories of “warm mix asphalt”, “Half-

warm mix asphalt” and “Cold mix asphalt”.

Cliff indicated that at European level the

key documents are BS EN 13108 and BS

EN 12697.There is also the need to cover

transport, laying and compaction, which

involves BS 594987. At National level

PD6691 is a key document. Other issues that

flow from specifying warm, half-warm and

cold mixes concern grading of reclaimed

asphalt which is widely used in these

products, and dealing with tar which can

be permitted in cold mixes but not in warm

and half-warm.

Readers are referred to PPR666, which can

be sourced as indicated at the start of this

report, for the details.

Peter Barclay, the Manager of the Midlands

Highway Alliance, gave a presentation on

a Local Authority perception of the path to

adoption of low temperature asphalt and

the drivers that influence their actions.

Reinforcing previous presentations he

indicated that the barriers are;

n No proven track record

n No tangible benefits

n Concerns about cold weather laying

n Supply

n Suitability

n Workability

n Too many types

n No standard LA carbon calculator

Also reinforcing previous presentations, as

well as adding a useful requirement, Peter

indicated that the next steps should include;

n Include in Harmonised Specification

as an option

n Encourage more pilots

n Monitor usage and performance

between locations/use/authorities etc.

n Measure benefits and build confidence

n Case studies and evidence

n Need to develop an evidence database

n Set up and monitor usage KPIs.

e.g. % used/tonnage per authority

n Develop case studies nationally

to highlight benefits (HMEP)

n Develop a universal carbon calculator

Issue Measure

Fragmented and dwindling human resource Establishment of a knowledge transfer network

Absence of a forum for cross industry sharing of knowledge especially LAs

Collaborative working groups - as element of UK Roads Board for example

Lack of skills and technical knowledge Demonstrate that expert knowledge offers potential savings. Introduce technology at lower risk levels first to build understanding and create a platform for trust and development

Possible mistrust between LAs/client and Contractor in respect of advice.

Critical need for impartial, authoritative, case studies.


CONFERENCE REPORT

Summary

It can be argued that this conference is one

of the most important held during the year,

or even in recent years, because it focuses

on a significant innovation being made

available within the paving industry, and

one which addresses the priorities of the

government based client.

There are clear groups of processes:

warm, half-warm, and cold which fall within

the general label of “Low Temperature

Asphalt” (LTA). It is clear from the papers

delivered at this conference that there are

no practical obstacles to the production

and laying of low temperature asphalt

mixes, and that cold mixes are already

included in specifications under the

“Retread” process which dates back to

the 1950s. It is equally clear that whilst

there are a few issues to be dealt with,

workable specifications and guidance can

and have been produced. Despite this, and

in the case of using cold mixes the fact

that specifications and practice has been

available for many years, the adoption of

LTA is facing some very strong barriers,

so it can be said that the most significant

information presented in the conference is

that related to the barriers. The LTA project

team, led by Lafarge Tarmac, are to be

commended for including a task to identify

“market barriers”. The table above shows

the top ten barriers that were identified,

and their sectors. Other presentations, and

most notably that by Peter Barclay, broadly

confirm these barriers, and underpin them

by providing information on client drivers,

such as “carbon content.”

It is notable that nearly all these barriers

have a “technical” component, the possible

exception being “affordability”, though even

that one does have a technical aspect if the

assessment of “affordability” includes

a cost-benefit or life cycle cost element.

The second most highly ranked barrier is

“knowledge and understanding”. It is clear

that the development of knowledge and

understanding of Low Temperature Asphalt,

in the broad context of how pavements

work and of paving materials will address

all the other barriers in the list.

It is widely known that the pavement

related skill base has been progressively

reduced in size for many years, and is under

pressure as a result of the need to reduce

expenditure in response to the recession,

particularly in local government, where

there are also demographic pressures

coming into play. This same recession is

creating a demand for innovation so that

“more can be done for less” and “value

for money” is improved. There is a clear

implication from this conference that

timely and successful innovation requires

knowledge and understanding, and it is to

be hoped that this message will be added

to the one that at the very least LTA has

passed two of the four hurdles (see notes

on Donna’s presentation) that it needs

to cross.

Rank Barrier Sector

01 Evidence of performance Perception

02 Knowledge and understanding Technical

03 Design Guidance Technical

04 Affordability Perception

05 Specification Technical

06 Impartial assistance Technical

=7 Personal views Perception

=7 Engineering skills Cultural

09 Confidence of success Cultural

10 Attitude to risk Cultural

Dr A F Stock Leader, Asphalt and Pavements Programme University of Derby

REVIEWS


Closer to your needs. Quicker to your door1.Thames Oil Port opening soon. Uniquely positioned to provide the South East with a local supply of bitumen products – for a faster, more efficient1 service for you. Which we think is the best way of getting closer to your needs.

Connect with Shell on +44 (0)870 201 7777 or visit www.shell.com/bitumen

1Based on Shell calculated delivery times to 71 Asphalt Plants within 250 km radius of Thames Oil Port compared to equivalent delivery times from Eastham Refinery. Calculations are based on delivering 25 Tonne loads, driving at an average speed of 63km/h, not taking delays into account.

108050 Shell_Surveyor_FullPage_210x297.indd 1 20/08/2013 10:19

Felixstowe Docks

Though the port has developed good rail links, the bulk of the 3 million-plus container units it handles travel through the port gates by road. The toll from the many thousands of trucks beating a path along the access road to this import and export hub is also, inevitably, heavy.

Over the years the Port Authority’s engineers have specified a range of materials to combat the problem of deformation. The materials used have ranged from traditional hot rolled asphalt (HRA) to advanced thin surfacing materials, but until now, those efforts have met with limited success.

The biggest issue has been the rutting of the pavement. Trucks passing through the gates of the port use a two-way, two-lane access road. Unlike on a motorway where there is a mix of vehicles and choice of lanes, the unrelenting, ‘channelized’ flow to and from the port is of heavy goods vehicles that barely deviate from the same track. Ploughing the same furrows, their wheels accelerate wear on the road surface, leading to ruts, cracking and further damage as the weather elements go to work beneath the rapidly deteriorating surface.

The civil engineering team at Felixstowe and its contractors R W Hill (Felixstowe) Ltd and Waveney Surfacing had already decided to use a thin surfacing with a polymer-modified bitumen when they approached asphalt supplier Eurovia Roadstone.

The Port of Felixstowe is not just Britain’s biggest and busiest port, it also boasts the best connections. Shipping lines operating from the port – which is the main hub of the ‘Haven area’ that includes Harwich and Ipswich – serve 365 ports around the world. And on terra firma, Felixstowe is just as well situated to distribute goods throughout the country. Some 70% of the containers coming through the port are delivered to the ‘Golden Triangle’ – an area in the middle of Britain where the high street brands and online retailers have their national distribution centres – only a short haul away.

“Several solutions were considered but the nature of the site and the type of traffic involved meant that UL-M would be the most resilient for this application,” says David Jones, Technical and Systems Manager, Eurovia Roadstone.

UL-M has a proven international track record (see box) but Jones could also point to a similar application closer to home. Lanes one and two of the Queen Elizabeth II Bridge were resurfaced with UL-M, more than five years ago, when the Thames crossing was operated by the Eurovia Group’s joint venture, Le Crossing. This surfacing is still bearing up well under the daily onslaught (more than 140,000 vehicles use the M25’s Dartford-Thurrock Crossing each day), and it’s believed to be the longest life cycle yet for the toll booth sections.

Resurfacing of the port’s access road was postponed twice due to adverse weather before going ahead on Saturday 20 April 2013. Waveney’s team planed off the old, failing surface to a depth of 40-50mm for the UL-M course. During production of the 116 tonnes of material, samples were tested at Eurovia’s Ipswich laboratory to ensure it conformed to the design mix. On site in Felixstowe, Eurovia Roadstone’s technician carried out an audit of the laying process, ensuring the material was installed to the system’s specific guidelines, an integral part of which is the use of a bond coat. This provides an excellent bond to the

underlying substrate whilst also providing waterproofing, ensuring a greater service life of the whole pavement.

“The whole operation went exceptionally well,” says John Murphy, Contracts Manager of Waveney Surfacing. “The material supplied and the cooperation from the plant were first-class, and the attention of Eurovia Roadstone’s materials technician also played such an important part in the successful completion of the contract.”

R W Hill (Felixstowe) Ltd and Waveney Surfacing have been associated with maintenance of Port of Felixstowe infrastructure for over 30 years and have been supplied by Eurovia for over 24 years, a long lasting relationship.

The toll of traffic on the access road can only get heavier. With Felixstowe aiming to double capacity by 2030, the port’s infrastructure – like its link to the British road network – must bear the burden of this growing trade.

The Port of Felixstowe:• Receives more than 4,000 ships each

year

• Handles more than 3.4m TEUs (twenty-foot equivalent units)

• Its 33 shipping lines offer 90 services to and from 365 world ports

• Can accommodate the world’s largest container vessels

The port is owned and operated by Hutchison Ports UK, a member of the Hutchison Port Holdings Group, which is a subsidiary of Hutchison Whampoa Ltd (HWL), the Hong Kong-based multinational conglomerate. HWL claims to be the largest foreign investor in the UK.

UL-MDeveloped in France during the 1980s, UL-M was the first conventionally installed thin surfacing system to be introduced to the United Kingdom.

UL-M utilises high-performance polymer-modified bitumen, which has high cohesion, low thermal sensitivity and excellent resistance to aging. Different degrees of modification make it possible to adapt the choice of binder to the performance requirements, nature and characteristics of the substrate, traffic loading and weather conditions.

HAPAS-approved, the UL-M thin surfacing system has been proven worldwide, with more than 100 million square metres laid around the world, of which some 20 million square metres are within the UK – mainly on motorways and urban roads, including notable locations such as London’s Park Lane, Victoria Embankment and Tower Hill.

UL-M can be specified with aggregates of varying sizes (6mm, 10mm and 14mm) and laid to thicknesses of 15-50mm.

Eurovia Roadstone | 1 Western Extension | Chequers Lane | Dagenham | Essex | RM9 6QD

T: 0208 593 7666 | F: 0208 593 7668 | W: www.euroviaroadstone.co.uk

IAT Felixstowe docks.indd All Pages 21/10/2013 17:33:09


ADVERTISEMENT

Felixstowe Docks

Though the port has developed good rail links, the bulk of the 3 million-plus container units it handles travel through the port gates by road. The toll from the many thousands of trucks beating a path along the access road to this import and export hub is also, inevitably, heavy.

Over the years the Port Authority’s engineers have specified a range of materials to combat the problem of deformation. The materials used have ranged from traditional hot rolled asphalt (HRA) to advanced thin surfacing materials, but until now, those efforts have met with limited success.

The biggest issue has been the rutting of the pavement. Trucks passing through the gates of the port use a two-way, two-lane access road. Unlike on a motorway where there is a mix of vehicles and choice of lanes, the unrelenting, ‘channelized’ flow to and from the port is of heavy goods vehicles that barely deviate from the same track. Ploughing the same furrows, their wheels accelerate wear on the road surface, leading to ruts, cracking and further damage as the weather elements go to work beneath the rapidly deteriorating surface.

The civil engineering team at Felixstowe and its contractors R W Hill (Felixstowe) Ltd and Waveney Surfacing had already decided to use a thin surfacing with a polymer-modified bitumen when they approached asphalt supplier Eurovia Roadstone.

The Port of Felixstowe is not just Britain’s biggest and busiest port, it also boasts the best connections. Shipping lines operating from the port – which is the main hub of the ‘Haven area’ that includes Harwich and Ipswich – serve 365 ports around the world. And on terra firma, Felixstowe is just as well situated to distribute goods throughout the country. Some 70% of the containers coming through the port are delivered to the ‘Golden Triangle’ – an area in the middle of Britain where the high street brands and online retailers have their national distribution centres – only a short haul away.

“Several solutions were considered but the nature of the site and the type of traffic involved meant that UL-M would be the most resilient for this application,” says David Jones, Technical and Systems Manager, Eurovia Roadstone.

UL-M has a proven international track record (see box) but Jones could also point to a similar application closer to home. Lanes one and two of the Queen Elizabeth II Bridge were resurfaced with UL-M, more than five years ago, when the Thames crossing was operated by the Eurovia Group’s joint venture, Le Crossing. This surfacing is still bearing up well under the daily onslaught (more than 140,000 vehicles use the M25’s Dartford-Thurrock Crossing each day), and it’s believed to be the longest life cycle yet for the toll booth sections.

Resurfacing of the port’s access road was postponed twice due to adverse weather before going ahead on Saturday 20 April 2013. Waveney’s team planed off the old, failing surface to a depth of 40-50mm for the UL-M course. During production of the 116 tonnes of material, samples were tested at Eurovia’s Ipswich laboratory to ensure it conformed to the design mix. On site in Felixstowe, Eurovia Roadstone’s technician carried out an audit of the laying process, ensuring the material was installed to the system’s specific guidelines, an integral part of which is the use of a bond coat. This provides an excellent bond to the

underlying substrate whilst also providing waterproofing, ensuring a greater service life of the whole pavement.

“The whole operation went exceptionally well,” says John Murphy, Contracts Manager of Waveney Surfacing. “The material supplied and the cooperation from the plant were first-class, and the attention of Eurovia Roadstone’s materials technician also played such an important part in the successful completion of the contract.”

R W Hill (Felixstowe) Ltd and Waveney Surfacing have been associated with maintenance of Port of Felixstowe infrastructure for over 30 years and have been supplied by Eurovia for over 24 years, a long lasting relationship.

The toll of traffic on the access road can only get heavier. With Felixstowe aiming to double capacity by 2030, the port’s infrastructure – like its link to the British road network – must bear the burden of this growing trade.

The Port of Felixstowe:• Receives more than 4,000 ships each

year

• Handles more than 3.4m TEUs (twenty-foot equivalent units)

• Its 33 shipping lines offer 90 services to and from 365 world ports

• Can accommodate the world’s largest container vessels

The port is owned and operated by Hutchison Ports UK, a member of the Hutchison Port Holdings Group, which is a subsidiary of Hutchison Whampoa Ltd (HWL), the Hong Kong-based multinational conglomerate. HWL claims to be the largest foreign investor in the UK.

UL-MDeveloped in France during the 1980s, UL-M was the first conventionally installed thin surfacing system to be introduced to the United Kingdom.

UL-M utilises high-performance polymer-modified bitumen, which has high cohesion, low thermal sensitivity and excellent resistance to aging. Different degrees of modification make it possible to adapt the choice of binder to the performance requirements, nature and characteristics of the substrate, traffic loading and weather conditions.

HAPAS-approved, the UL-M thin surfacing system has been proven worldwide, with more than 100 million square metres laid around the world, of which some 20 million square metres are within the UK – mainly on motorways and urban roads, including notable locations such as London’s Park Lane, Victoria Embankment and Tower Hill.

UL-M can be specified with aggregates of varying sizes (6mm, 10mm and 14mm) and laid to thicknesses of 15-50mm.

Eurovia Roadstone | 1 Western Extension | Chequers Lane | Dagenham | Essex | RM9 6QD

T: 0208 593 7666 | F: 0208 593 7668 | W: www.euroviaroadstone.co.uk

IAT Felixstowe docks.indd All Pages 21/10/2013 17:33:09

ADVERTISEMENT



ADVERTISEMENT

For your toughest challenges

www.nynas.com

If you are challenged to design an asphalt solution that can handle the toughest

circumstances, bring that challenge to us. We will show you how we have applied our

toughest binder, Nynas Endura, to challenges all over Europe and fi nd the right design

for your needs. Want to know more? Visit nynas.com/endura

DOCKS AIRPORTS RACETRACKS ANY HEAVY TRAFFIC AREA

Talk to us about Nynas Endura

11-0008tg-NYN_Ad_Endura_Hamn_FINAL.indd 1 2012-06-11 15.49

ADVERTISMENT


O’Hara Bros buy new Dynapac SD2500WS paver for work across London’s road network

The SD2500WS paver continues to be well

received with O’Hara Bros Surfacing adding

one to their fleet. O’Hara Bros Surfacing

are looking for increased efficiency from

their machines to reduce fuel costs and

down time so the ergonomically designed

SD2500WS was a great fit.

O’Hara Bros Surfacing, established over

thirty five years ago, have expanded their

fleet of pavers to cope with the increasing

demand in London and surrounding areas.

The company, that has its own Aggregates

Division, is based in North London and takes

on contracts across the capital on some of

London’s busiest and most prestigious roads.

Michael O’Hara, Operations Director for the

surfacing firm, explains why he chose the

SD2500WS, “We chose the Dynapac machine

as we think it’s the best on the market,

especially after trialing it. Our work tends to

be very demanding requiring high amounts

of asphalt being laid in short time frames.

That’s why we need pavers we can rely on

and back-up we can count on.” Michael goes

on to say the efficiency of the paver helps

them achieve their goals of cutting fuel

costs and increasing productivity.

Donato Campanaro, Sales Manager for

Road Construction Equipment says, “O’Hara

Bros are a large and professional outfit

that needed a high capacity and reliable

paver. The SD2500WS is such a versatile

machine it easily met their wide ranging

requirements.”

The Dynapac paver combines

outstanding paving performance

with excellent operator comfort

and fuel efficiency. It is part of

a renewed focus from Dynapac

on the UK market, offering more

ergonomic, economical and

robust machines for these

tougher economic times.

Atlas Copco is an industrial group with world-

leading positions in compressors, expanders and

air treatment systems, construction and mining

equipment, power tools and assembly systems.

With innovative products and services, Atlas Copco

delivers solutions for sustainable productivity.

The company was founded in 1873, is based

in Stockholm, Sweden, and has a global reach

spanning more than 170 countries. In 2012,

Atlas Copco had 39 800 employees and revenues

of BSEK 90.5 (BEUR 10.5). Learn more at

www.atlascopco.com

Road Construction Equipment is part of the

Construction Technique business area. The

division is a leader in asphalt, soil and concrete

applications, committed to customer performance

worldwide. Products and solutions are marketed

under the Dynapac and complementary brands.

Headquartered in Wardenburg, Germany, the

division has production facilities in Europe, USA,

South America, and Asia.

For further information please contact: Jessica Porter, Marketing & Communications Manager – Construction Technique +44 (0) 1442 222 407 or +44 (0) 7971 650 444

Mark Black, Business line Manager – Road Construction Equipment +44 (0) 845 601 0001 or +44 (0) 7971 650 492


NARC

REPORT On MEETIng – 11 SEPTEMBER Temperature Effects on warm Mix Asphalt Performance Venon Jalali

(The presentation was given by Dr

James Grenfell as Mr Jalali had a prior

commitment.)

Warm Mix Asphalt technology makes use

of additives to modify the temperature/

viscosity relationship in the bitumen and/

or the mix. This project will determine

the implications of the inevitable cooling

which takes place between mixing and the

completion of compaction, particularly what

happens if mixtures are produced at lower

temperatures than those specified, and will

investigate the fundamental reason for any

changes identified.

Two additive technologies have been

selected for the study:

n Sasobit Wax technology

n Rediset LQ chemical additive, which

works by modifying the mix

The additives will be combined with a

0/14mm limestone aggregate (granite

aggregates will also be used in the testing

matrix to assess compatibility) and three

grades of bitumen, 160/220 pen, 70/100

pen, 30/45 pen.

To date, a detailed literature review has

been produced which is included in an

interim university report.

The three grades of bitumen, combined

with three levels of addition of each of the

additives, have been characterised with

penetration and softening point tests,

by measuring viscosity at a range

of temperatures in a Brookfield viscometer,

and with Dynamic Mechanical Analysis.

Testing on the combination of bitumen

and additives has shown that;

n Sasobit decreases the penetration and

increases the softening point of the

bitumen.

n Rediset LQ has no effect on pen and SP.

n Sasobit decreases the viscosity above its

melting point, but below this point has

an adverse effect

n Rediset appears to have no effect on

the viscosity.

n Sasobit increases the complex shear

modulus (G*).

n Readiset LQ has minimal effect on the

complex shear modulus (G*).

n Sasobit improves the wetting potential

of the binder.

n Readiset appears to have no effect on

the wetting potential of the binder,

although it does change the acid and

base components of its surface energy.

Tests carried out on mixes have shown that

addition of Sasobit can lead to a reduction

in production temperature of 15°C and lead

to increased bulk density. It has been shown

that addition of Rediset LQ can lead to a

reduction of 20°C in production temperature

and to increased bulk density.

It is important to note that the project is

at an early stage and, as yet, no tests have

been carried out to assess the effects of the

additives on the mechanical performance

of the asphalt mixes.

Influence of moisture on asphalt mastic mechanical properties Dr Alex Apeagyei

This project is part of a Research Council

sponsored program researching the micro-

mechanical interpretation of moisture

induced damage in asphalt. The objective

of Dr Apeagyei’s project is “to determine the

constituent material parameters necessary

for Finite Element simulation of moisture

damage in asphalt pavements”.

Two types of aggregate, one being granite

and the other being limestone have been

selected for the research programme,

together with a 40/60 pen bitumen. The

test programme is being carried out on a

mastic mix with the following proportions –

25:25:50 (bitumen:filler:fines) by weight.

Two mechanical tests have been selected:

a tensile tests using a “dog bone” shaped

specimen for stress-strain properties, tensile

strength and to estimate poisson’s ratio; and

an adhesive test in which a 3mm thick layer

of the mastic is used to stick two prepared

stone substrates together.

Test samples were conditioned by soaking

them in water at 20°C for 110 days, and

water uptake was monitored by looking

at the change in weight with time.

The observations to date have shown

that moisture has little effect on the bulk

properties of the mastic, but that it causes

a rapid degradation in bond strength at

the aggregate – mastic interface.

HElD On wEDnESDAY 11 SEPTEMBER 2013The Nottingham Asphalt Research Consortium is a research-led collaboration between the Universities of nottingham and Cambridge

and companies which are active within the asphalt and paving industries. The Consortium meets at regular intervals and provides

the forum for a co-operative dialogue between academia and industry to develop, evaluate and implement innovative solutions

to pavement problems. Members pay a subscription which is used to fund research on topics that are defined collectively by the

members of the consortium and to fund the technical meetings.

The IAT, as the learned society concerned with disseminating technical knowledge through the Asphalt Industry, has been granted

“observer” status by the Consortium.

Report on the meeting of the Nottingham Asphalt Research Consortium (NARC) Report by Tony Stock

NARC


The role of Contact Pressure in Pavement Engineering Dermot Casey

This project is part of a Marie Curie Initial

Training Network (ITN) programme “Training

in European Asset Management.” The

overall goal of the network is to assess

infrastructure by innovative methods.

Traditionally the stress applied to a

pavement through a pneumatic tyre

has been modelled as a uniform vertical

pressure applied over a circular area. It has

been widely known that his is not a precise

model and that tyres apply transverse and

longitudinal stresses to the pavement as

well as vertical ones. The majority of work

carried out to date is a study of the US

“Perpetual Pavement” structure using a

finite element research program CAPA-3D

from TU Delft, which allows simulation of

a moving wheel load, using a sinusoidal

loading function which includes horizontal

stresses.

The following response parameters were

calculated:

n 38mm of surface course mix

n 150mm of base mix

n 75mm of asphalt treated drainage layer

n 150mm of cement stabilised base layer

n 175mm of aggregate subbase layer

The perpetual pavement consists of:

n Maximum strains, on the transverse and

longitudinal directions, in the asphalt

surface.

n Maximum tensile strains in the

transverse and longitudinal directions

at the bottom of the asphalt layers.

n Maximum vertical compressive strain

at the top of the subgrade

n Maximum shear strain in the asphalt

layers – under and beside the tyre

There were two wheel configurations

compared, a dual tyre system, as seen

on many commercial vehicles, and a new

generation wide (super single) tyre with a

contact width of 378mm.

It was observed that significant reductions

in the time required to analyse a pavement

could be achieved by changing the finite

element mesh to larger elements with

depth, without sacrificing the precision of

the analysis. This reduces the computation

required, allowing more pavements to be

analysed.

The analysis showed that details of the tyre

construction, such as the tread pattern, axle

load and inflation pressure, had significant

effects on the detailed distribution of strain

in the asphalt layer very near to the surface.

The difference between the simple uniform

stress model and the detailed model is

important when modelling the development

of permanent deformation. This difference

can have a significant impact on the

prediction of the pavement life, especially

for the surface and near surface layers.

From Binder to Mixture; Multiscale Permanent Deformation Behaviour Mahmoud Elnasri

This project is seeking to investigate

the interaction between components in

terms of permanent deformation of the

asphalt mixtures by a staged process of

characterising the pure bitumen and mastic

phase first, followed by characterising the

mortar phase, and then the asphalt mixture.

The experimental programme involves

shear and uniaxial creep and creep recovery

testing and some preliminary results on

the mastic and mortar phases have been

reported.

In the first phase mastic mixes with 35%,

50%, and 65% filler have been tested.

The preliminary results show an expected

result that, as the filler content increases,

the resistance to deformation increases

and the steady state conditioned can be

characterised by the Modified Cross Model.

Recovery tests, carried out at 50ºC and

30ºC, indicate that recovery is in a linear

relationship with the applied strain up to

a limit, after which it becomes constant.

The constant recovered strain is

independent of temperature and increases

with increasing stress level and/or reducing

the filler content. A brief description of

new developed multiple stress-strain

creep recovery test was presented.

Similar tests were carried out on the

mortar phase, in addition to the uniaxial

compression test. The results have shown

that behaviour deviates from that predicted

by the Modified Cross Model and that of the

mastic phase, at high temperature, due

to the effect of the aggregate.

Testing of the third phase, an asphalt mix,

will include X-ray characterisation of the

structure of the sample to study the coarse

aggregate and air voids influence.

BEnEFITS OF nARC MEMBERSHIP All NARC members have the right to

attend the regular technical meetings. The

membership decides the topics for these

meetings which brief members on the latest

developments in relevant research, often

well before it appears via electronic media,

conferences and journals. In addition to

being an excellent networking opportunity

this is a very cost effective way of ensuring

that members are kept abreast with the

latest developments in technology.

In addition to the technical meetings for

members, NARC runs courses during the

year on topics that are of interest to the

Asphalt Industry, and members are entitled

to preferential rates.

Individual member companies also have

the opportunity to develop a dialogue

with University staff in relation to any

developments and innovations that

they are considering.

Future activities.

nARC Courses: The following short (one day) courses are planned:

‘Higher-Volume Hot Mix Recycling’ – provisionally 27th June 2014 (Jukka Laitinen, Nynas)

‘Asphalt: What’s around the corner’– Joint SCI/NARC Seminar 20th March 2014 (Nizar Ghazireh, Lafarge-Tarmac, James Grenfell, NTEC)

For further information on nARC and its activities visit the website at www.nottingham.ac.uk/narc

ASPHALT EXCHANGE


Asphalt Exchange

lInKED In – HOT TOPICS SInCE lAST ISSuE ARE HRA AnD RAP

14mm Pre Coated Chips for HRA - Has anyone any experience with using 14mm rather than 20mm PCC? My main query revolves around the fact

that 20mm PCC being the norm where I am,

is there any considerations or adjustments

to be made to the chippers to facilitate

chipping with 14mm PCC? Any experience

or helpful tips would be appreciated.

“We used to use them on 25mm thick

HRA overlays, and surface courses on

new build development quiet back streets

back when I worked with the councils in

Scotland as 20mm chips would simply be

too big to embed. Although the surfacing

teams used to hate laying HRA that thin

on carriageways compared with the

40mm thick used everywhere else.”

“I’m the same as xxx with 25mm Overlays

but only in summer, all the chipper

operator has to do is a tray test and turn

the chipper down and the roller driver

needs to be right up to the back of the

chipper. Our squad had no problems with

the 14mm pre-coats apart from them

sticking together.”

“As xxx mentions, it’s usually used on

thinner overlays. I’ve seen it used on

mastic asphalt bridge decks on a 35mm

overlay. If the overlay is in thicker you

may get over embedment. To check the

rate of spread required you can use the

test where you get a 1m X 1m tray and

tessellate the chips touching shoulder

to shoulder and weigh them. Smaller

trays 500mm X 500mm or ever 250mm

X 250mm can be used. If I remember

you are looking for 70% or 75% of the

shoulder to shoulder weight of 1 Sq/m”

“IMO I’ll never understand why HRA has to

be a departure. It’s still has it’s place and

is successfully used, on major roads, on a

daily basis in Scotland. I can’t help thinking

we are throwing the baby out with the

bathwater.”

We‘ve had some positive feedback on the newly tweaked AsPro – keep it coming please!

“I’m with xxx on this one, although

when working with a Local Authority the

bathwater got too hot and it was SMA

that was banned and HRA made a quick

comeback. I have overlaid quite a few

housing estate roads successfully with

30/14 at 25mm thick with 14mm precoats

and even 30/10 with the same results but

I would never lay the spec Jennifer was

given. I have laid 30/14 design mix 50mm

thick with 20mm pre coats on roundabouts

overnight and still looks OK.”

“Probably digressing but I’ve only seen

14mm PCCs applied for ‘aesthetic’ reasons,

normally into AC 4 Fine Surf. We had to

increase the binder content to allow for

the PCCs to roll into the mat more easily.”

Has anybody any experience with using additives to treat mixtures with RAP to increase the workability of the mixture?

“We are currently experimenting with 55%

RAP in HMA with 2% 40/50 pen bit for our

BTB mixes. Only down side is that when

the mix gets below 125 celsius it becomes

a bit “hard” to rake and make neat joints.

We have used this in our BTB mixes and

compaction results are all good. We are

currently adding 10% RAP to our medium

HMA with great success.”

(Member from South Africa)

“Dr Helen Bailey from the TRL has done

some interesting work on this - worth you

chasing up. But before you go down the

additive route, from past experience, you

will obviously need to factor in the Pen of

your RAP feedstock. PD6691 suggests P15

as a (I think?) minimum value. You will

need to mix your BASE/BIN with a much

softer binder grade to achieve 50pen in

your final mix if you are adding 20-30%

RAP.”

“http://www.greenwisebusiness.co.uk/

news/first-ever-chip-fat-road-laid-in-

bedfordshire-841.aspx Have a look at this.

Worth a read anyway. Can you not switch

one tank to 250/330 and then blend?”

I had expected a full inbox, both with emails and letters since the last issue, but it hasn’t been quite that prolific,

however, people do have plenty to say elsewhere. Various topics have been debated on LinkedIn and I’ve chosen a

couple to look at in detail. The site has grown to almost 1800 members now and the discussions are lively and varied,

with global opinion that always makes for a good read. We‘ve also had some positive feedback on the newly tweaked

AsPro – keep it coming please! A couple of members said they would like to hear more about what our members get

up to away from the world of work, so we have included some details of how people have helped charity recently.

Note from Ed: The IAT is planning a

debate with regards to HRA v SMA early

in 2014 in the Western Branch region,

to be held jointly with the IOQ. Please

keep an eye on the events page on

the website for details.

Note from Ed: The technical papers

talked about in this article were

published in the 2013 Yearbook.


ASPHALT EXCHANGE

“I have done it and designing the RAP

asphalt milled to virgin materials and

it’s used in Entebbe International Airport

Project in Uganda. I have repeated it also

in Pilot project in Chalinze Dar-es salaqm

road project in Tanzania using Super paved

Gyratory compactor and I’m using 45%

Rap asphalt mix with 55% Virgin asphalt

way back 90’s and we don’t have prob”

(Member from Sri Lanka)

“In the Netherlands base layers containing

up to 60% rap have been produced

and processed successfully. In most

cases pen100/150 or pen 160/220

bitumen is used. For higher percentages

strict handling of the rap is required in

combination with rejuvenators.”

(Member from the Netherlands)

FEEDBACK On THE nEwlY TwEAKED ASPRO “@The_IAT just had a quick half-time flick

through #aspro like the layout. glad to

see “reader’s drives” back! #sexyroad“

“like it! Especially the sections that

encourage member comment/input.

The technical sections remain good

as ever and I note the Branch input

seemsmore comprehensive.”

“great stuff.”

“My overseas issue ( Belgium ) arrived

today. looks good !”

“Really liked it, in particular the peer

review and the Asphalt Exchange.

upping the game springs to mind.......”

“Tar porn at its best. Marvellous!”

Chris and friends

MEMBERS wHO gIVE THAT lITTlE BIT EXTRA What do people get up to outside of the

industry? Well, Ray Wood and his wife

raise money for charity. Ray gives talks

on ‘Antiques’ and Marylyn on ‘Women

in Avaition’ and ‘Wind Tunnel testing for

military and civil aircraft’. They open their

garden to local groups providing cream teas

or cheese and wine and Marylyn pots up

around 150 plants for sale. And this year

they have just organised a dinner auction

of ‘Antiques, Art and Collectables’. So far

this year they have raised in excess of

£3500 for Marie Curie Cancer Care.

Past President walks part of the Camino de Santiago For the past 4 years Chris Lycett, past

President of the IAT, and a small group

of his friends have walked a section of the

Camino de Santiago (The Way of St. James).

The walk follows medieval pilgrimage

routes from towns and cities over Europe

and beyond to the small city of Santiago

de Compostela in Northern Spain. Legend

has it that St James was buried in the city

following his death

in Jerusalem in 43 AD. Traditionally, pilgrims

walked the Way of St. James, often for

months, to arrive at the great church in the

main square of Compostela to pay homage

to St. James.

Note from Ed: Sadly our Irish members

did not receive their hard copy – we have

now rectified this oversight and they

should receive it at the same time as

all other members in the future (postal

service willing!)

Nowadays, the route is walked by people

from many cultures and backgrounds for

reasons other than religious. In Chris‘ case,

he enjoys the hospitality of the people

in the region and exploring the beautiful

countryside at a walking pace.

He also arranged sponsorship from friends

and colleagues back home and in the IAT for

a children’s hospital charity in Dublin. This

year he received donations of over €2000

for the charity. He is very pleased with

the donations which will be used to fund

research into diabetes in children and

young adults.

AggREgATE InDuSTRIES SAlES TEAM TARgETS HOSPICE CARE In THE wEST Liz Halliwell (Secretary of Western Branch)

and Denise Selvaggio (Member of Western

Branch) have organised several charitable

events as part of Aggregate Industries’ drive

to help the local community. The Frome

Office nominated local charity Dorothy

House Hospice Care as their charity of the

year and organised several fundraising

events consisting of homemade cakes, jams

and home-grown vegetable sales, so far

raising £119.61. In addition to this, on 14th

September members of the Asphalt Sales

and Order Team participated in the Bath

8km Midnight Walk, dressed for the occasion

in their onesies. The challenge was keeping

everyone awake until midnight! It was an

enjoyable night and they were very proud

to be part of the 1100 participants for such

a special cause close to their hearts. They

raised a brilliant total of £807 to contribute

to the events final total of £110k.

why not tell us about what you’ve been doing to help others or any challenges you’ve been a part of?

The girls from the AI Sales team at Frome.

ASPHALT EXCHANGE


Bolden Nuggets – Episode 1MEATS wITH OuR APPROVAl

Was I the only one to be absolutely

shocked to find that some unscrupulous

manufacturers were putting horsemeat

into some of those nutritious and delicious

budget level value “Hamburgers”?

Yes reader, I was indeed shocked to the

core to find that there was meat of any

description whatsoever in those things.

To be honest, at those prices I’m surprised

we weren’t eating E number flavoured soil.

Let’s face it, for 25p a throw somebody has

to gather up all the ingredients, transport it

to a factory, turn it into something that in

an extremely bad light may just about pass

as edible, add lots of expensive packaging,

put it onto lorries and drive halfway round

the world and then get some retailer to sell

it onto us. Hardly surprising then that it may

be just a little less than top-quality meat

in there.

Basically – you get what you pay for. If you continually drive down costs the quality of what you get will suffer.

Luckily our politicians were on hand to

explain that it (a) had absolutely nothing to

do with them and (b) they were powerless

to stop it and (c) that there would be a full

enquiry to discover what went wrong and

most importantly who is to blame. Of course,

as Harold Wilson most famously pointed

out, public enquiries do not discover who

is to blame. No, they are there precisely to

make sure that nobody ever finds out who

is to blame. True to form, despite enquiries,

police investigations and much pontificating

by the press, nobody has yet been charged

with anything remotely illegal. True to, form

the leader of the opposition explained that

he was absolutely outraged – yet again!

While failing to explain a little less than

candidly that it was actually his lot, while

he was himself was in government, which

relaxed the rules and allowed this sort of

thing to happen in the first place.

Not quite sure what all the fuss is about

personally, indeed in Belgium these Neddy

burgers would be considered a gourmet

treat. It is difficult to understand why we

British can separate animals into distinct

categories such as: cute, furry and cuddly as

opposed to cute, furry and edible. What is it

within our national psyche that decrees that

poor old Daisy and Flossie can be served up

as a main course: whereas good old Rover,

Tiddles and Dobbin are strictly off menu,

it is completely nuts!

Of course what is really at issue here is

how we view the true cost of the food we

eat. Therefore, we insist on trying to force

down the cost of food and to hell with the

consequences. Then as a direct result of

this, we are going to find ourselves eating

reconstituted mush that bares little or no

resemblance to what it is we thought we

ordered. Basically – you get what you pay

for. If you continually drive down costs the

quality of what you get will suffer. Perhaps

there’s a lesson for all of us there.

gOT SOMETHIng TO SAY? wHY nOT JOIn In OuR ASPHAlT EXCHAngE?

we welcome your emails, letters, tweets, phone calls and texts. You may want to let us know your opinion on a recent issue,

tell us about something exciting that is happening, thank someone for something, send us a picture, talk about an IAT event

you’ve been to, or just let us know you’re there and interested - we will review everything that comes our way and perhaps

use it in the next issue. You can contact us in various ways by calling 07787 501652 or emailing

[email protected] or by post to PO Box 17399, Edinburgh, EH12 1FR

Asphalt Professional is YOuR magazine - we want you to be involved!

Bob Bolden

Note from Ed: Some of you remember

Bob’s ‘President’s View’ a few years

back. We now welcome him back

to AsPro with a regular column.


ASPHALT PEOPLE

Chris Hudson – Council MemberWe introduce Chris Hudson to you. He is enthusiastic about being a part of Council and plans to use his knowledge and experience

to help take the IAT in the right direction.

How did you start in the industry?

From school I joined Tilcon as a management

trainee – they sponsored me through

Doncaster College and Leeds University.

what did you do before your

current role?

Varied career – Operational Director for

various AI businesses including pre-cast

concrete, train and barges businesses,

merchanting etc.

what do you do in your current role?

Profit responsible for the asphalt business –

involves travel across the country, customer

meetings etc.

How long have you been doing it?

Since beginning of 2011.

why did you choose it?

(or have it thrust upon you)

I was ‘volunteered’.

what is the best thing about it?

The people – great team.

what is the worst thing about it?

Nothing.

where do you get your information

from to do your job better?

Trade publications, IAT, MPA and discussions

with customers, suppliers and stakeholders.

Have you done /received anything

memorable?

Led the aggregate supply to the Olympic

Park build over three years, involving

frequent visits.

Describe a typical day?

There is no ‘typical’ day – each one

is different.

would you recommend your job

to another person?

Yes.

would you recommend them to

start in the industry? why/why not?

It’s a great career with plenty of opportunity

to get responsibility at an early age.

when did you join the IAT Council

and why?

I joined the institute in 2012 in order to

get more information regarding the industry

and also to offer assistance in direction.

what do you want to achieve

whilst on Council?

To assist it in continuing to help

educate the industry.

Is there anything that worries

you about your role?

Consistency in public spending.

How do you want to see the

IAT grow in the future?

With industry education at its core.

Is there a message you want

to give the members?

Continue to learn if you want to survive!!

Chris HudsonAsphalt Director

Born: 1958

Brought up: Devon

Education: Degree and MBA

work for: Aggregate Industries

Since 1986

Job Title: Asphalt Director

IAT Role: Committee Member

Note from Ed: We’d like to feature members from all areas of our industry. If you know

someone who’d like to tell us about what they do, get in touch with your answers and

a headshot.

ASPHALT AMUSEMENT


Remember, it’s just for fun – answers in the next issue!

ASPRO CROSSwORD

Note from Ed: We are still looking for a

crossword compiler – please contact us if

you fancy having a go

Asphalt Amusement

where’s that Road?What a stunner!

Reader’s DrivesLast issue’s specimen was

from Malcolm Simms, MPA,

but which Dr does this one

belong to? I am reliably

informed it was all his/her

own work too.

note from Ed: If you’ve got

any fabulous pics of roads and

other asphalt surfaces in the

UK, send them in and we’ll

print them. #sexyroad

note from Ed: Send us pics

of your drive and let’s see

if we can guess – some clues

might be a good idea too!

So you’ve reached the end of our new look Asphalt Professional. What did you think? Please let us know via email, Twitter or LinkedIn – we’d love

to hear from you! [email protected], @The_IAT or www.linkedin.com – look for The Institute of Asphalt Technology in Groups.

Across

1 Difficult to believe (4,2,7)

8 Be servile (4)

9 Sideways (8)

10 Presence (10)

12 Nun’s headgear (6)

14 Breathe out (6)

15 Annihilate (10)

19 Banter (8)

20 Stench (4)

21 Clergyman (3,2,3,5)

Down

2 Slaughterhouse (8)

3 Close knit (5)

4 Late (7)

5 Van, lorry (5)

6 Simple, unsophisticated (3-4)

7 Expel (4)

11 Misuse (3-5)

13 Condition (7)

14 Drastic (7)

16 Minimum (5)

17 Bucolic (5)

18 Molten matter from volcano (4)

ASPHAlT AnAgRAM

‘Adopt harlot’s hell’

last issue answer –

Asphalt Professional of course!

Answers from last issue:

Across: 2. Members 3. Conference

6. Road 9. Professional 10. Asphalt

11. Geraldine 13. Arthur 14. Jukka

Down: 1. Pavement 3. Contractor

4. Laboratory 5. Twitter 7. Technology

8. Bitumen 9. Pothole 12. Aggregate

#

Cut

here

#

asphaltprofessional - institute of asphalt technology · pavement design and maintenance technical...

Documents