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Highway Specification Appendix E Contents 1. Introduction 1.1 Link with Highways Agency's

Manual of Contract Documents for Highway Works

1.2 Future Amendments to specification

2. General Roadworks

Requirements 2.1 Structural Design 2.2 Structural Testing 2.3 Quality Assured Bituminous

Materials 2.4 Sampling and Testing 2.5 Road Construction Programme 2.6 Surface Levels of Pavement

Courses 2.7 Road Categories 2.8 Sustainable Drainage 2.9 Compliance with EC

Standards 3. Drainage

3.1 Pipes 3.2 Manholes, Gullies and other

Chambers 3.3 Manhole and Gully Positions 3.4 General Details 3.5 Covers and Frames

4. Carriageway Construction

4.1 Natural Formation 4.2 Design 4.3 Capping Layer 4.4 Sub-Base 4.5 Base 4.6 Binder Course 4.7 Surface Course – Distributor

Roads 4.8 Surface Course – Other Roads 4.9 Handling of Bituminous

Mixture 4.10 Carriageway Construction

Thickness 5. Footway Construction 5.1 Surface Course 5.2 Binder Course 5.3 Compaction 5.4 Weedkiller 5.5 Vehicle Crossings 5.6 Medium Temperature

Asphalt for Heavily Trafficked Footways

6. Miscellaneous Items 6.1 Grassed Areas 6.2 Services Margins 6.3 Visibility Splays 6.4 Traffic Signs and Road

Markings 6.5 Small Element Paving 6.6 Block Paving Alternatives 6.7 Coloured Surfacings 6.7.1 Resin Based Skid Resistant

Surface treatment

6.7.2 Coloured Surfacing for Traffic Calming and Surface Delineation Purposes

6.7.3 Coloured Surfacing for Cycle Tracks

6.7.4 Slurry Seal 6.7.5 Grouted Macadam 6.8 Cycleway Construction 6.8.1 Flexible Surfacing for

Cycleways 6.8.2 Cycleway Edging 6.8.3 Lighting Details 6.9 Dowel Bars in kerb

foundation and shared surface roads, mews and courts

6.10 Protection of Utilities from root growth

6.11 Dressed Natural Stone Setts 6.12 Advice on Design and

Specification issues

Index of Appendices Sub-Appendix 1/1 Notes for Guidance for Construction Works 1. Testing Regime 2. Design for Carriageway 3. Capping Layer 4. Sub Base 5. Base and Binder Course 6. Surface Course Sub-Appendix 1/2 Table 1– Air Void Requirements Carriageway Construction Table 2 – Air Void Requirements Footway Construction Table 3 – Equilibrium CBR Values Sub Appendix 1/3 Highway Ironwork 1. Introduction 2. Procurement Policy Sub-Appendix 1/5 Testing Frequencies and product certification (by the Developer) General Requirements

Sub-Appendix 1/7 1. Carriageway Construction

Materials 2. HRA SC for Footways 3. Recycling of Highway

Materials 3.1 Recycled Granular material 3.2 In-situ Recycled Material in

Base 4. Stone Mastic Asphalt Surface

Course Sub-Appendix 1/10 Highway Works Details Sub-Appendix 1/11 Surface Levels of Pavement courses Sub-Appendix 1/12 Formation Weedkiller Application Sub-Appendix 1/13 Construction Works in the vicinity of trees

Highway Specification (1.0) Introduction (1.1) This Specification for the development of residential estate roads supersedes previous guidance issued by Staffordshire County Council and is supplied as a guide to Developers and their Road works Contractors. It is not intended to be fully comprehensive and works must comply with the Manual of Contract Documents for Highway Works Specification for Highway Works and Highway Construction Details (MCDHW) current at the time of construction unless amended by this document. Developers are advised to acquire these two volumes of the MCDHW. (1.2) Future Amendments to Specification The details and requirements contained in this specification are correct at the time of issue of this document. It will, from time to time, be necessary to update and amend the specification to reflect changing technology and policies.

Developers are therefore recommended to check with the County Council’s Development Control Section that the edition of the specification which they intend to utilise, for incorporation into their development proposals, is the most up to date version available.

The document has now been placed on the County Council’s Website: (www.staffordshire.gov.uk/transport/roadand pathwaymaintenance/staffordshirehighways/highwaycontrol/ResidentialDesignGuide.htm)

(2.0) General Roadworks Requirements (2.1) Structural Design The Structural Designs referred to in this Specification assume a carriageway formation CBR of less than 2%, which requires a capping layer 600mm thick. However, if the Developer is able to provide formation equilibrium CBR values (see Sub-Appendix 1/2 Table 3) of 2% or greater, then the capping layer thickness may be reduced - see 4.10 Table 4. (2.2) Structural Testing This Edition of the Specification reiterates the need for “Air Void” coring upon completion of the Developer’s road works.

Cores will be removed and tested in accordance with Sub-Appendix 1/5. Road pavements and footpaths found to be sub-standard in either, material types, thickness, or degree of compaction, will not be adopted as Publicly Maintained Highways until defects have been remedied at the Developer’s expense. (2.3) Quality Assured Bituminous Materials All bituminous mixtures used in the works shall be produced in plants that are registered to BS EN ISO 9002 ‘and National Sector Scheme 14 “Production of Asphalt Mixes” and shall, after 1st April 2008, be laid by contractors registered to and operating in accordance with “Sector Scheme 16 for the Laying of Asphalt Mixes”. All non-proprietary asphalt mixtures shall be CE marked and comply with BS EN 13043 and the relevant annex of BSI PD 6691. (2.4) Sampling and Compliance Testing The Developer will be required to arrange for the sampling and testing of certain works, goods and materials. These are listed in Sub Appendix 1/5.

The Developer shall, upon request, provide the County Council with details of applicable Quality Management and Product Certification Schemes and one copy of all relevant test results. In addition, the Authority may require other sampling and testing of certain works, goods and materials, in which case the Developer shall render any access and assistance necessary. All testing and assessment work shall be carried out at the Developer’s expense The County Council’s Highways Laboratory is available to carry out testing work for Developers on a rechargeable basis. The Developer may elect to employ an alternative UKAS accredited testing laboratory to carry out material testing on his behalf; this will not obviate the necessity for testing work which the County Council may wish to carry out. Where an alternative laboratory is to be employed by the Developer care should be taken to ensure that the work is carried out to Staffordshire County Council’s specifications and requirements. The use of the County Council’s Highways Laboratory may, by use of local knowledge and historic information, allow a reduction in certain testing frequencies.

In any event, highway construction will only be adopted as Publicly Maintained Highways where all appropriate testing and assessment work has been carried out and results have been provided. (2.5) Road Construction Programme The road construction details assume that carriageways will be completed to final surface course level before they are subjected to the design traffic loadings. However, the Developer may wish to construct his roadworks in two stages, initially to top of base or binder course level, and then to final surface course level. This is permitted, but at the Developer’s own risk. In the event of the partially completed roadworks deforming, deteriorating or failing in any way, the County Council will require the necessary remedial and/or reconstruction works to be carried out before the roadworks are completed.

Where two stage construction is adopted, particular importance shall be given to thoroughly cleaning the existing surface prior to the superimposition of succeeding layers, and to the placement of material at the carriageway edge. Where base and binder course layers are completed prior to kerb laying, material subsequently placed between bituminous layers and the kerb face shall be adequately compacted.

Concrete (ST 2) may be used in-lieu of base and also binder course where the void between binder course and kerb face is <100 mm wide. Where the void is >100mm, the longitudinal edge of binder course shall be saw cut and binder course material shall be removed up to approximately 300mm from the kerb face. Vertical faces shall then be coated with bituminous edge seal prior to compaction of additional binder course material. Surface course materials, which in any way become damaged by the development works, shall be replaced at the Developer’s expense before the works are adopted. (2.6) Surface Levels of Pavement Courses These shall be constructed to comply with the requirements of MCDHW, Clause 702. (2.7) Road Categories This Specification covers different categories of road. Listed in Table 1 are the most common categories, the construction specification of which varies according to the road type. It is essential that the road category is clearly marked on the plans submitted for approval. Details of the road hierarchy are included in Appendix A of this Design Guide dealing with access layout.

(2.8) Sustainable Drainage Where it is feasible to provide a conventional positive drainage system, there will be a presumption that this is the preferred option. S100 (9) of the Highways Act includes for soakaways, therefore local authorities cannot decline the long term maintenance of such facilities on the grounds that a non-conventional system of drainage has been provided. Accordingly, where a conventional drainage system is not a practical option, a Sustainable Urban Drainage System (SUDS) will be considered for adoption providing that:-

• the developer provides comprehensive details of the porosity of the ground into which the soakaways will discharge, together with appropriate design calculations;

• a maintenance plan is provided detailing the method to be adopted when the soakaway is desilted, including access arrangements to the soakaways;

• a commuted sum is secured in respect of the extra cost of maintaining the system, over and above that for a conventional system.

The use of soakaway chamber will normally only be considered as a ‘last resort’ drainage measure, because of the inherent maintenance liability in comparison with that associated with balancing ponds and/or swales. Where soakaway chambers are to be used, then the maintenance will normally be carried out by the Highway Authority and a commuted sum commensurate with the projected additional maintenance liability will be required. Where SUDS involve the use of swales and/or balancing ponds outside the highway boundary, then clearly defined maintenance arrangements must be agreed prior to the adoption of the highway infrastructure. The presumption will be that, under normal circumstances, areas outside the highway boundary will be maintained by the District Council as public open space. Accordingly, such schemes being proposed for approval under Section 7 of The Staffordshire Act 1983 will need to:

• furnish evidence that the District Council will take responsibility for such maintenance;

• indicate the surface water drainage connections and

• where appropriate, the easements that would be required;

Where developers propose to use balancing ponds, appropriate measures must be included in the design to mitigate risks associated with drowning particularly in respect of children. A safety audit may be required. Permeable surfaces are not currently considered suitable for adoption due to the risks associated with inducing inadequate stability in the carriageway structure, due to water logging. Until statutory powers are available to govern the respective responsibilities of the relevant local authorities and drainage/ water authorities in respect of SUDS, it will be necessary to draw up ad-hoc agreements to define the shared responsibilities for drainage from land, roads and properties.

Table 1

(2.9) Compliance with EC Standards Any requirement in this document that any material or article shall comply with any specified standard, whether a British Standard, other named standard or otherwise, shall be satisfied by compliance with any relevant national or governmental standard of any member state of the European Communities, or any relevant international standard recognised in such a member state, provided that, in either case, the standard in question offers guarantees of safety, suitability and fitness for purpose equivalent to those offered by the Standard which is specified in this document, demonstrated to the satisfaction of the Highway Authority.

Road Category

Abbreviation

Distributor Road DR Collector Road CR Connector Road CN Major Residential Access Road

Maj RAR

Minor Residential Access Road

Min RAR

Minor Access Way MAW

Any requirement in this document to use a material or an article which is defined by reference to a named supplier or manufacturer or a specified Quality Assurance scheme or Agreement Certificate or HAPAS Certificate or which is registered with, or has otherwise received the approval of the Highway Authority, shall be satisfied using material or an article which has received equivalent approval in another member state of the European Communities, provided that the material or article in question is as safe, suitable, and fit for the relevant purpose, as a material or an article complying with the requirements as set out in this document, demonstrated to the satisfaction of the Highways Authority.

(3.0) Drainage (3.1) Pipes Materials for pipes will be restricted to clay, concrete or plastic, as approved for use by the appropriate Water Authority. (3.2) Manholes, Gullies and other Chambers Manholes, and other chambers shall be constructed in pre-cast or in situ concrete, or Class B engineering brickwork. Gullies connected to surface water drains may be fabricated from precast concrete, brick or insitu concrete with a plastic liner. All concrete and mortar shall incorporate sulphate resisting Portland cement.

(3.3) Manhole and Gully Positions (a) Manholes/catchpits should be provided at:

(i) every change of gradient or alignment

(ii) every change in size of pipe

(iii) a maximum spacing of 90m.

(b)Gullies should be positioned so that:

(i) The area draining to each road gully does not exceed 200 square metres.

(ii) The spacing of gullies does not exceed 50 metres along each channel.

(iii) Double gullies are provided at all low points on a concave channel profile. In this circumstance, separate connections should be made to each gully.

(iv) At all road junction, pedestrian crossings and private drive entrances they are sited on the upstream side of the road.

(v) The maximum length of connection is 20 metres

(3.4) General Details (a) The laying of pipes shall

start from the point of outfall immediately after completion of trench excavation.

Pipe lines shall be laid to straight lines and gradients. The lengths between manholes shall not be backfilled until they have been inspected and approved.

(b) Drainage works will not

be inspected for approval unless the sides of trenches and other excavations are adequately supported.

(c) Concrete grade ST1

shall be used to provide bed and surround for pipes:

(i) under carriageways

where the cover to the top of the pipe is less than 1.2m;

(ii) under any other part of the highway where cover is less than 0.9m;

(iii) wherever the cover

exceeds 5.0m; (iv) where directed by

the Highway Authority.

(d) Redundant gullies shall have gratings and any supporting brickwork removed and the pot filled with concrete grade ST2.

(e) A piped outfall discharging

into a ditch or watercourse shall have an invert level at least 150mm above either the level of average flow or the bed level, whichever is the higher. The angle of discharge shall not be greater than 60° to the direction of flow in the ditch or watercourse and a headwall shall be provided, to a design approved by the Highway Authority or the Environment Agency, to support the bank and to prevent scour.

(f) Drains shall be tested and

cleaned as described in MCDHW, on completion of the Works, and at other times at the direction of the Highway Authority. The drainage system shall be cleaned at the end of the maintenance period prior to the joint inspection for adoption. A CCTV survey of the system shall be carried out after completion of the Works and before the end of the maintenance period. A copy of the video tape shall be supplied, free of change, to the Highway Authority before the Works are adopted.

(3.5) Covers and Frames Attention is drawn to the significant change in the way that the supply and installation of gully and manhole ironwork is specified. All units shall comply with BS EN 124 as supplemented by BS 7903 and they shall also be supplied and installed following the guidance of Highways Advice Note HA104/02, contained within the Design Manual for Roads and Bridges vol. 4. Notes on the selection and installation of ironwork are given in Sub Appendix 1/3 (4.0) Carriageway Construction (4.1) Natural Formation If details of existing ground conditions are not available, the natural formation shall be assessed to ensure that the strength assumptions made in the design of the Developer’s roadworks can be substantiated. Fill materials shall be classified and placed in accordance with the requirements of MCDHW 600 series: acceptability parameters and testing regime shall be agreed, with the County Council’s Staffordshire Highways Laboratory, on a site specific basis.

(4.2) Design Carriageway construction layer thickness is specified in 4.10. A formation CBR of less than 2%, requiring 600mm of capping layer, will be assumed unless the developer is able to provide test results to show otherwise. A reduced capping layer thickness should not be allowed solely on the basis of in-situ CBR testing. Soil classification tests shall be used to assign an “Equilibrium CBR” based on material type, using table 3 in Sub-Appendix 1/2. (4.3) Capping Layer Capping layer shall comply with MCDHW table 6/1 class 6F2, 6F3 or 6F5 and be compacted following the requirements of table 6/4 method 6. In-lieu of testing to show full table 6/1 compliance it may be acceptable to show grading compliance supplemented by in-situ testing to demonstrate a bearing capacity of at least 15% CBR (or equivalent); contractors shall follow the requirements of table 6/4 method 6 in all circumstances. Material within 450mm of the finished road surface shall be non frost susceptible.

(4.4) Sub-base Sub-base material shall be manufactured, to comply with MCDHW Clause 801 & Clause 803. Where a Developer is not able to demonstrate full compliance with Clause 801 & Clause 803 then an acceptable alternative may be to show Clause 803 grading and plasticity compliance supplemented by in-situ tests to show a minimum dynamic stiffness of 70MN/m2, when tested using the light drop-weight tester. Other sub-base materials may be approved for use, but the Developer must demonstrate equivalent performance prior to their use. MCDHW clause 803 requires sub base to be produced under a “Factory Production Control” (FPC) system; details of suppliers FPC and test results shall be provided to the Council upon request. (4.5) Base Base materials shall be constructed using AC 32 Dense Base 100/150 recipe mix complying with Table B.11 of PD6691:2007. The asphalt shall be machine laid, except where agreed otherwise. Certain alternative construction materials and techniques, employing the use of recycled materials or in-situ stabilisation, are available. The use of Granulated Fly Ash (GFA) or Foamed Bitumen are examples. Specification details for recycled materials are given in Section 3 of Sub Appendix 1/7 of this Appendix.

Full specifications for these processes are available on request from the County Council’s Highways Laboratory and their use may be agreed on a site-specific basis. The base shall be constructed only after drains, sewers, service pipes and any other underground works have been satisfactorily completed. (4.6) Binder course Binder course shall be constructed with AC 20 Dense Bin 100/150 recipe mix to Table B.11 of PD6691:2007 except across bridge decks where HRA 50/20 Bin 40/60 to Table C1 of PD 6692:2007 shall be used. (4.7) Surface Course-Distributor Roads The surface course shall be either SMA 10 surf 40/60 or SMA 14 surf 40/60 to Table D1 of PD 6692:2007, as appropriate, with a minimum PSV appropriate to traffic flow but generally not less than specified in table 3. Staffordshire County Council’s Specification for Stone Mastic Asphalt, as detailed in Sub Appendix 1/7 gives supplementary information on the design and use of SMA.

(4.8) Surface Course-Other Roads The surface course shall be HRA 55/10 F surf 100/150 to Table C.2A of PD 6691:2007. The coarse aggregate shall be crushed rock with a minimum PSV appropriate to traffic flow, but generally not less than specified in table 3. An alternative option shall be SMA 10 surf 40/60. (4.9) Handling of Bituminous Materials All bituminous materials shall be transported, laid and compacted in accordance with the requirements of BS 594987, as supplemented or amended by the requirements of this document, to achieve the in-situ void levels in Sub-Appendix 1/2, table 1 when tested as described in BS EN 12697:8. (4.10) Carriageway Construction Thickness All carriageways will be constructed in accordance with Table 3.

Table 3 – Carriageway Construction Requirements

Road Type Surface Course

Thickness and material

Binder course

Thickness and material

Base Thickness

and material

SMA 14 surf 40/60,

40mm thick min psv 60

Distributor Road (inc. all industrial/ commercial roads)

SMA 10 surf 40/60

40 mm thick. min psv 60

AC 20 Dense Bin 100/150

recipe 60mm thick.

AC 32 Dense Base 100/150

recipe mix 200mm thick.

Collector/ Connector / Major Access Road

HRA 55/10 F surf 100/150 to


AC 20 Dense Bin 100/150

recipe 60mm thick.



Minor Residential Access/ Minor Access Way / Mews Courts / Housing Squares

HRA 55/10 F surf 100/150


AC 20 Dense Bin 100/150 recipe mix

60mm thick.



Carriageway sub-base and

capping Table 4 – Carriageway Sub-base and Capping Thickness CBR value of formation

Layer thickness

CBR 15% or greater 150mm sub-base CBR 5% to less than 15%

225mm sub-base laid in 2 layers (max single layer thickness 125mm)

CBR 2% to less than 5%

150mm sub-base plus 350mm capping

CBR less than 2% 150mm sub-base plus 600mm capping

For determination of formation CBR see section 4.2.

(5.0) Footway Construction Flexible footways on housing developments shall be constructed, as shown on standard detail drawing in Appendix 1/10, to the following thickness and specification. (5.1) Surface Course Adjacent to local Distributor Roads, Collector Roads, Connector Roads and in shopping areas, the footway surface course shall be 25mm thick SMA 6 surf 100/150 to Table D1 of PD 6692:2007, with reference to sub appendix 1/7, or HRA 45/6 surf 160/220 proprietary material as specified in Section 5.6 this document. In other areas the surface course shall be 20mm thick AC 6 Dense surf 160/220 to Table B15 of PD 6691:2007. The minimum PSV of coarse aggregate shall be 50. (5.2) Binder Course On all footways the binder course material shall be 50mm thick AC 20 Dense Bin 160/220 recipe mix to Table B.11 of PD6691:2007 (5.3) Compaction All asphalt layers shall be compacted to achieve the air void requirements specified in Sub-Appendix 1/2 Table 2.

(5.4) Weed Killer An approved weedkiller shall be applied to the sub-grade before laying the sub-base. The specification details are included in Sub-Appendix 1/12 (5.5) Vehicle Crossings Dropped crossing consisting of two type BNC150 x 125mm and two dropper kerbs types DL, DR, complying with the requirements of BS7263: Part 3: 2001 shall be constructed in the kerblines at the start and termination of all footways and across bellmouths. Footway crossings are shown on the Standard Detail Drawings in Sub-Appendix 1/10. (5.6) Heavily Trafficked

Footways HRA for use in heavily trafficked footways (near shops and schools and on higher category roads) The material shall comply with the general requirements of EN 13108:4 and Sub-Appendix 1/7 Table 1 and shall be designated HRA 45/6 surf 160/220 proprietary material as specified in Section 5.6 this document The coarse aggregate shall be crushed rock with a minimum PSV of 50. The minimum temperature on discharge from the delivery lorry shall be 135°C. The material shall be compacted to achieve air voids as specified in Sub-Appendix 1/2 table 2.

(6.0) Miscellaneous Items (6.1) Grassed Areas Turfing and Seeding shall be carried out in accordance with MCDHW clause 3005, using the seed mix specified below.

The developer will ensure that grassed areas are mown at least once before adoption, and on adoption, vegetation should not be more than 50mm high. Hydraulic mulch seeding may be permitted on areas with difficult access, subject to the prior approval of the proprietary process by the Development Services Directorate or Agent Authority.

(6.2) Service Margins

(a) In the absence of a footway, (e.g. on shared service roads) underground management services shall be located in grass service margins. A grass service margin must be rolled to give a satisfactory appearance and achieve a gradient of 1 in 12. In order to avoid damage to the mains and services, the planting of trees and shrubs in the service margin will not be normally permitted, except under a Licence to Plant, which must be obtained from the County Council or Agent Authority.

(b) Where the highway

boundary is not delineated by a wall or fence, the grass service margin must be clearly delineated on site by the means of granite setts at 2.0m intervals laid such that the top surface is flush with (and not proud of) the turf level between cross-over points. The intention here is that the grass service margin should appear to be part of the adjacent garden, and maintained by the frontages as such.

Perennial Rye Grass S23 27kg Red fescue S59 9kg Smooth Stalked Meadow grass

4.5kg

Crested dogstail 5.0kg White Clover S100 4.5kg

Notwithstanding the desirability of encouraging the frontagers to maintain the service margin, it will be necessary for the developer to ensure that a clause is provided in the individual plot conveyances, clearly indicating that the service margin does in fact form part of the publicly maintained highway.

(c) The developer will need to

comply with the specific requirements of the relevant statutory undertakers. In addition sewers, water mains and other underground services must be laid in accordance with the diagrams given in this specification and cross-connections shall be reduced to a minimum.

Work in connection with the installation of all services, and the subsequent reinstatement of trenches shall, wherever possible, be complete and the trenches fully consolidated before carriageway foundation work commences, and at all times, this must comply with the requirements of the HAUC specifications for reinstatement.

Where underground cables and services etc. are to be installed at some later date, suitable ducts under the carriageway must be provided at the expense of the developer, unless otherwise provided by the statutory undertaker, and their positions permanently marked.

(d) The developer is reminded of his responsibility for any gas, water, telephones, sewer or other service or main which may be damaged or require support during the progress of the road works. The cost of any such works, including any diverting of existing services carried out by the statutory undertakers concerned, is to be met by the developer.

(e) Where the installation of Cable Television will result in significant disturbance to footways and other public areas, a suitable duct for cable TV shall be included as part of the overall service arrangements for the site, at the outset. When developments are likely to be served by the Cable TV network, prior agreement should be reached with the National Joint Utilities Group and the Highway Authority as to the positioning of any necessary ducting.

(f) Where work is to be undertaken to form a development road connection, or other vehicle crossing to an existing highway, attention is drawn to Section 184(9) of the Highways Act 1980 (as amended by Chapter 22 of the New Roads and Streetworks Act 1991 and any other amendment or enactment in force at the time of the construction of the works), with regard to statutory undertakers plant.

Attention is also drawn to Section 50 of that Act regarding the licences necessary for non-statutory apparatus which includes requirements in respect of insurance against third party liability. Any duct, cable or concrete surrounds thereto must be at least 380mm below finished carriageway level.

(g) Special attention must be

paid to cross-over points. The specification should be 30mm dense surface course with a 50mm binder course (see section) and a minimum of 150mm sub-base. The width should be a maximum of 6m and slightly splayed to a maximum of 0.5m. The extremity of the service strip within the cross-over point should be delineated by the use of bullnose kerbs.

(h) The entrance to a Shared Service Road will be via a physical demarcation which is located 10m back from the channel line of the priority road. This demarcation line must comply with current legislation for traffic calming and would normally be 1m in width. The footway at such a location should extend for 2m beyond the carriageway demarcation line.

(6.3) Visibility Splays A flat topped edging kerb, as described in 6.2(b) shall be provided on the highway boundary every 5m and two blocks laid end-to-end shall be fixed at every change in direction along the line of the highway boundary. (6.4) Traffic Signs and Road Markings All developments shall be signed and marked with white and yellow lining as appropriate. The signs and markings shall be in accordance with The Traffic Signs Regulations and General Directions 2002.

(6.5) Small Element Paving Where appropriate, small element 80mm thick concrete block paving for roads shall be laid on a foundation comprising machine laid 100mm minimum compacted thickness of AC 32 Dense Base 100/150 recipe mix complying with Table B.11 of PD6691:2007 compacted to achieve a maximum air void as specified in Sub-Appendix 1/2, Table 1. The underlying sub-base shall comply with MCDHW Clauses 801 & 803. Alternatively, the dense asphalt concrete may be replaced by ST2 material complying with MDCHW Clause 1001 laid to a minimum compacted thickness of 130mm. Concrete blocks to be laid in accordance with the Code of Practice BS6717: Part 3. 50mm minimum laying course. Clay and Calcium Silicate Pavers to be laid in accordance with the relevant Code of Practice for design and construction BS6677: Part 2 and Part 3 respectively specified thickness 50mm laying course. Samples of bedding sand shall be submitted for approval at least 2 weeks before it is intended to be used onsite.

(6.6) Block Paving Alternatives Where a block paved finish is required in a situation where block paving construction is unsuitable, because of the propensity for the paving to become dislodged or subside due to repeated impact or channelised traffic loading, then an acceptable alternative would be the use of a hot applied, polymer modified, synthetic bitumen-based compound, incorporating graded rubber and granite aggregates reinforced with metal and glass fibres. This type of surfacing may be applied to sound bituminous and concrete surfaces, however, a tack coat must be applied to concrete surfaces for extra adhesion. The block paving texture is produced by placing a metal grid over the spread material. Suitable materials are available in proprietary form which:

(a) provide a skid resistance in

excess of SRV55 having a curing time of approximately 45 minutes;

(b) penetrate the jointing sand

used between block paving and, on polymerisation, bind sand particles together and to the sides of pavers.

(6.7) Coloured Surfacings The choice of coloured surfacing materials shall be governed by the degree of usage in terms of volumes of vehicular pedestrian and cycle traffic likely to use or cross the surfaces. (6.7.1) Skid Resistant Surface Treatment The specification and method of application shall be in accordance with Clause 924 of the HA's Specification for Highway Works. Under normal circumstances, a calcined bauxite aggregate with a minimum PSV of 70 will be required. Treatments shall be HAPAS approved and used in situations appropriate to the class of certification.

(6.7.2) Coloured Surfacing for Traffic Calming and Surface Delineation Purposes Coloured surfacings for traffic calming and surface delineation purposes shall, wherever practical, be coloured variants of HAPAS approved skid resistance treatments. The aggregate used shall have a PSV appropriate to the location but shall have a minimum value of 55. The surfacing shall be spread to achieve a finished thickness of 3 – 5 mm (10 – 12.5 kg/sqm).

For sites subject to high traffic volumes a high durability material complying with MCDHW Clause 924 classification reference-type 1 will be required.

For Traffic Calming purposes the aggregate colour shall normally be BS381 Signal Red. (6.7.3) Coloured Surfacing for Cycle Tracks Coloured surfacing shall be applied to achieve a finished thickness of between 2 and 3mm with a coverage rate of not less than 6.7 – 7.1 kg/m2. The aggregate shall have a minimum PSV of 55. The colour of the aggregate shall normally be BS381 Signal Red. (6.7.4) Slurry Seal Slurry seal to BS 434 Parts 1 and 2 laid at 6mm nominal thickness with a minimum PSV of 55 complying with Clause 2 to 19 of Clause 918 Volume 1 of the HA's Specification for Highway Works. The colour shall normally be BS381 Signal Red for Cycle Tracks. (6.7.5) Grouted Macadam Where a coloured surface course is required e.g. in connection with the surfacing of a cycle track or the definition of traffic calming or bus lay by feature, an acceptable alternative is the use of a thin macadam surface course incorporating a liquid asphalt grout.

Such treatments have the advantage of colour longevity and durability due to the pigmented material being integral to the wearing course. Proprietary products are available which enable a wide range of surfacing colours to be utilised. (6.8) Cycleway Construction The guiding principle in selecting the appropriate treatment should be the achievement of the lowest whole life cost, compatible with the delivery of a satisfactory level of services. Thus the need to provide surface treatments such as resin based anti-skid surfacing should be questioned to ensure that the subsequent maintenance costs are justified in the circumstances.

(6.8.1) Flexible Surfacing for Cycleways

- Surface course 20mm thick

- Binder course 50mm thick

- Granular Sub-Base 150mm thick

- Surface course to be AC 6 Dense surf 160/220 in accordance with Table B15 of PD 6691:2007, Minimum PSV 55

- Binder course to be AC 20 Dense bin 160/220 recipe mix in accordance with Table B.11of PD 6691:2007

- Cycle tracks that are

constructed as part of the carriageway shall be constructed to carriageway standards.

- The specification for coloured surfacing is referred to in Para. 6.7.3 of this Appendix.

(6.8.2) Cycleway Edging

Footway edging shall be 150mm x 50mm concrete footway edging to BS 7263 Part 3, Type EBN. (6.8.3) Lighting Details The role of footways and cycleways do not necessarily reflect the road hierarchy. For example, a Strategic Route with high levels of traffic flow may well have very little if any pedestrian activity. Conversely a minor access road may have a predominance of pedestrian movement.

The following table identifies a separate hierarchy for footways and cycleways which has been determined by pedestrian usage and/or the proximity of schools or industrial premises, which attract an unusually large number of pedestrians and is therefore appropriate for use in determining the appropriate lighting requirements for individual sites.

Table 5 Cycleways Lighting Details

Footway/

Cycleway Group

Definition Lighting Class*

1 Very heavily used fways/cycleways e.g. Town centre pedestrian precincts, footways near very large schools, factories and offices.

S1

2 Very heavily used fways/cycleways e.g. Small shopping parade fways, footways near schools, factories and offices not included in Footway Group 1

S2

3 Frequently used fways/cycleways e.g. in residential areas and villages or fronting houses in rural areas.

S4

4 Other fways/cycleways i.e. little used rural

S5

* Lighting Classification Codes as per BS 5489. (pr. EN 13201; 1998 Parts 1 and 2).

Except where a cycleway forms part of the adjacent highway or footway infrastructure, separate lighting should be provided in all urban and suburban locations. The level of lighting for cycleways shall be as for Corresponding footway categories defined in the above table. (See Appendix B for Lighting Specification).

(6.9) Dowel bars in kerb foundation concrete on access and shared surface roads, mews and courts Where it is intended that concrete kerb foundations will be constructed sufficiently in advance of the kerb laying operations for the protruding dowel bars to form a hazard, the Developer may opt instead to form a continuous shear key recess, in the upper surface of the kerb base, 100mm top width x 50mm deep x 70 mm bottom width.

The recess shall be at least 175mm from the base face of the kerb base and shall be thoroughly cleaned and coated with neat cement grout immediately before the kerb backing concrete is placed.

(6.10) Protection of Utilities from Root Growth

Proprietary materials are available which when positioned between Utility Company’s plant (including highway drainage) and tree roots, acts as a barrier and prevents the roots from growing into the services and these shall be used where there is a risk of root growth causing damage to adjacent utility plant. (6.11) Dressed Natural Stone Setts Dressed natural stone setts shall comply with BS435 and shall be laid in accordance with the relevant sections of BS7533. In particular, setts shall be laid on a 150mm wet lean concrete bed; Grade ST3 concrete; jointing and painting shall be in high strength (HA designation I 1;:¼:3 cement, lime, sand mix), with a Styrene Butadience Resin (SBR) admixture to facilitate durable bonding.

(6.12) Advice on Design and Specification issues Highways Design, Maintenance and Laboratory staff are available to give technical guidance on design and specification issues. Enquiries on specification issues should be addressed to:

Staffordshire County Council Development Services

Department Staffordshire Highways

Laboratory Sandyford Street Stafford ST16 3NF Tel: 01785 277360 Fax: 01785 277370 Other enquiries should, in the first instance, be addressed to:

Staffordshire County Council Development Services Directorate Development Control Section Riverway Stafford ST16 3TJ Tel: 01785 276597 Fax: 01785 211279

References 1. BS EN 12697 Bituminous

mixtures - test methods for hot mix asphalt, part 5 determination of maximum density and part 6 determination of bulk density

2. Highway Agency Manual of

Contract Documents for Highway Works, Volume 1 Specification for Highways Works SHW, Volume 2 Notes for Guidance Volume 3, Highway Construction Details.

3. BS EN 13108:1, 4 and 5

Asphalt concrete, Hot Rolled Asphalt and Stone Mastic Asphalt specification requirements

4. PD 6691 guidance on the use

of BS EN 13108. 5. British Standard 6717, Part 3,

Code of Practice for Laying Concrete Blocks.

6. British Standard 6677, Parts 2

and 3, Codes of Practice for Design and Construction for Clay and Calcium Silicate Pavers.

7. BS 594987 Specification for

transport, laying and compaction and type testing protocols.

Sub-Appendix 1/1

Notes for Guidance 1. Testing Regime

From the Design Guide Specification cl 2.4, Sub-Appendix 1/5 work is entirely the responsibility of the Developer, who must produce details of Quality Management Schemes, Product Certification details etc, as requested by Staffordshire Highways staff. The Developer must also give “access and assistance” to Staffordshire Highways staff to carry out any necessary additional sampling and testing work that may be required. This work may be carried out by SHL, again at the Developer’s expense.

2. Design for Carriageway

Construction Carriageway construction

layer thickness is specified in cl 4.10 Table 3. A formation CBR of less than 2%, requiring 600mm of capping layer, is assumed unless the developer is able to provide test results to show otherwise.

Reduced capping layer thickness should not be allowed solely on the basis of in-situ CBR testing. It is intended that soil classification tests be used to assign an “Equilibrium CBR” based on material type.

3. Capping Layer

This should be 6F2, 6F3 or 6F5 material. The Specification for Highway Works (SHW) specifies the placement of capping to a “method”. However, a developer must demonstrate that his material complies with SHW Table 6/2 grading requirements, and placed as appropriate. Plate testing on the compacted material must be carried out to demonstrate that the design assumption of 15% Equivalent CBR has been achieved. Full SHW Appendix 1/6 method specification requires Optimum Moisture Content to be determined and the material moisture content to be measured at point of deposition to show that it complies with the specified range of Optimum Moisture Content to Optimum Moisture Content - 2%

The use of 6F2, 6F3 or 6F5 material is specified. The finer graded 6F1 and 6F4 materials are likely to be more susceptible to moisture content problems and 6F1 and 6F4 material outside the specified moisture range is less likely to provide adequate bearing capacity.

4. Sub-base Type 1 sub-base should be

placed to a method specification (SHW). Clause 803 and Table 8/1 specifies compaction and layer thickness requirements. Note that the most common layer thickness is 150mm and in Staffordshire County Council’s experience the most common roller used by developers is a BOMAG 120AD or equivalent. A roller of this type (less than 1300kg/m width) is unsuitable for 150mm thick layers. If an unsuitable roller has been used or if any doubt over the Table 8/1 method having been followed then the Design Guide cl 4.3 requires plate testing at the developers expense. SHL can give guidance about the selection of suitable rollers.

5. Base and Binder course Core sampling shall be

carried out routinely on every scheme to check for air voids and layer thickness. Cores are normally cut through binder course and base but contractors should note that they cover the roadbase at their own risk.

6. Surface Course Core sampling of surface

course is normally only carried out if problems are suspected.

SUB-APPENDIX 1/2

TABLE 1: AIR VOID CONTENTS OF COMPACTED MATERIALS USED IN CARRIAGEWAY

MATERIAL MEAN OF 6 CORES

MEANS OF ANY PAIR

Min. %

Max. % Min. %

Max %

AC 32 Dense Base 2 8 1 10 AC 32 or AC 20 Dense Bin

2

7

1

9

All HRA surf and bin 2

6

1

8

10mm 2 6 1 8 SMA surf 14mm 2 6 1 8

TABLE 2: AIR VOID CONTENTS OF COMPACTED MATERIALS USED IN FOOTWAY

MATERIAL MEAN OF 6 CORES

MEANS OF ANY PAIR

Min. % Max. % Min. % Max %

AC 20 Dense bin 2 9 1 11 AC 6 dense surf 2 9 1 10 SMA 2 7 1 9

TABLE 3 Equilibrium CBR Values to be used for design purposes within Staffordshire

Soil Type Plasticity Index

Equilibrium CBR %

Clay/Silt

“ “ “ “

Silt Silt

Poorly graded SAND Well graded SAND

Poorly graded GRAVEL

Well graded GRAVEL

50 or greater

35 - 49 26 - 34 16 - 25 10 - 15

less than 10 Non-plastic

“ “ “ “

less than 2

3 4 3 2

less than 2 less than 2

7 10 10 15

N.B.(i) Granular material with greater than 15% passing 63 µµµµm test sieve will be considered on a site specific basis. (ii) CBR values for made or placed ground may be determined using insitu methods if the material is granular in nature.

Sub-Appendix 1/3 Highway Ironwork

1. Introduction

A significant change to this edition of the Design Guide is the requirement for ironwork to be selected and installed following the advice set out in the Highways Advice Note HA 104/02 2. Procurement Policy Only products that fully comply with EN 124 as supplemented by BS7903, and HA 104/02 are permitted Notes for Guidance on Interpretation of HA 104/02 Notes for Guidance on the Selection, Installation and Maintenance of Chamber Tops and Gully Tops The following notes are not intended to be a substitute for HA 104/02. 1. Introduction and Scope. 1.1 The document covers most

aspects of selection and installation of chamber tops, gully tops and associated bedding systems and materials.

1.2 Premature failure is a major problem. Failures are not usually of the frame and cover but of the adjacent surfacing due to ‘rocking’ frames after the failure of the supporting system and/or bedding.

1.3 Recent research has shown that failure of the bedding material is one of the main factors. Conventional materials and procedures have become superseded by recent developments, improved specifications for bedding materials and improved frame and cover designs are available.

1.4 HA 104/02 sets out ‘Best Practice’ and defines materials.

HA 104/02 should be considered to supersede previous SCC procurement requirements and installation methods

2. Definitions 2.1 HA 104/02 Chapter 2 lists

definitions and terminology.

3. Design considerations for

chamber and gully tops. 3.1 Chamber tops and gully

tops shall be specified to comply with BS EN 124 and HA 104/02.

3.2 The minimum class of chamber top or gully top to be installed in major carriageway locations shall be D400. In traffic categories 5 and 6, where the ironwork is to be subjected to only occasional traffic loading up to 5 tonnes, class C250 may be used.

3.3 Where ironwork is located in the wheel paths of major routes, carrying >1500 cvd in each direction, then class E600 ironwork is required.

3.4 All products used shall have been assessed and certified as required by HA 104/02 and shall have been issued with product conformity certificates to BS EN 124.

Design of Chamber Tops. 3.5 Any chamber constructed

for man-entry purposes, with a rectangular opening, should have a minimum clear opening of 600mm with a diagonal measurement >700mm. Circular openings should be 700mm minimum diameter. Triangular openings should have a minimum diametric measurement of 700mm.

3.6 Class D400 frames should be a minimum 150mm deep. The depth of insertion of the cover within the frame should be 50mm minimum if the cover is secured or 80mm minimum if relying on the depth of insertion for security.

3.7 Seatings of covers in frames shall be such that stability and quietness are achieved without the need for cushioning inserts or the need for periodic maintenance.

3.8 The frame bearing area

shall be designed in such a way that:

a. The nominal bearing

pressure, in relation to the appropriate BS EN 124 test load, shall not exceed 2.1N/mm2.

b. The minimum bedding width of the frame at any point shall be 50mm.

3.9 Frames weighing more than

15kg should be provided with lifting holes, located to permit a balanced lift.

3.10 Frames should not contain bedding flange holes located beneath the cover seatings. Any bedding flange holes present should be allowed for when calculating the bearing pressure under test load.

4. Design of Gully Tops. 4.1 Gully tops shall comply with

BS EN 124 and HA 104/02 4.2 Hinged gully gratings and

frames may be kerb hinged or side hinged as appropriate to the traffic flow. The minimum area of waterway should be 900cm2

5. Bedding Materials. 5.1 Chamber tops and gully

tops shall be bedded using material with the following properties : a. Non-shrink. b. Minimum workable

life of 15 min. c. Compressive

strength >30N/mm2 in 3 hrs.

d. Tensile strength > 5N/mm2 in 3 hrs.

5.2 This specification is for a rapid hardening material and is typically achieved by the use of resin based products.

5.3 Bedding materials should be laid strictly in accordance with manufacturers recommendations, taking particular account of site conditions, temperatures and thickness of material used.

5.4 Packing material may be used provided that it is within the recommendations of the mortar manufacturer.

6. Packing Material. 6.1 Packing materials have

historically been used to raise the finished levels of chamber and gully tops, while retaining the existing supporting structure e.g. in overlay maintenance work.

6.2 However, SHW clause 507 clearly does not intend packing materials to be used. If packing material is to be permitted then it should be purpose made. It should be ensured that the product is compatible with the bedding material used. The use of materials such as quarry tile and slate is not permitted.

7. New Installation. 7.1 Frame supporting structure

shall be constructed to such level that packing materials, within the bedding mortar, are not needed.

7.2 Operatives should be appropriately trained.

Mixing Mortar

7.3 Mechanical mixing is preferred; the maximum quantity mixed should not exceed 50kg. Hand mixing is allowed, with a maximum mix of 25kg. Manufacturer’s recommendations for mixing, water content etc shall be followed.

7.4 Bedding must be placed onto the chamber without delay after mixing and floated to an even finish approximately 5mm thicker than required.

7.5 When using polymer resin materials the following points should be noted :

a. Harmful vapour may

be produced and the use of gloves, goggles and barrier cream is recommended.

b. Select the appropriate grade of product to suit temperature conditions and the time available for the initial set.

c. Setting may be very rapid and bedding must take place promptly.

d. The bond may be impaired if the surfaces are not kept clean and dry, site conditions may require extra measures to maintain a dry and clean condition.

e. Removal of frames previously bedded with resins is likely to damage the supporting structure.

f. Once set the material is inert and is therefore not classed as toxic waste.

g. Any unmixed material must be mixed prior to careful disposal (COSHH) and in accordance with manufacturers' instructions.

Placing of frames and covers

7.6 Health and Safety considerations mean that frames should preferably be lowered into positions with mechanical lifting devices.

7.7 The frame shall be placed

so that the bedding flange, webs etc are fully supported and there must be no voids between the bedding material and the frame.

7.8 The frame must be tamped down to the appropriate level.

7.9 Any holes within the frame must be filled with bedding material and the frame flange enveloped by a minimum of 10mm of the same material. A greater thickness is permitted provided that sufficient depth is available for surfacing layers.

7.10 Exposed bedding shall be floated to fill any voids and the bedding material inside the chamber must be pointed to a smooth finish.

7.11 Covers should be placed in the frames after the bedding is sufficiently set, preferably using a mechanical lifting device .

7.12 No surround material shall be placed until the bedding has achieved sufficient tensile and compressive strength

8. Reinstatement Works.

General Considerations

8.1 a Reinstatements of failed installations are likely to be carried out against time constraints.

b. Frame supporting structures may need renovation.

c. Time constraints may make bedding thickness limits unrealistic.

d. Usual layered construction of surround material may not be possible or desirable.

e. Re-use of frames and covers requires Client approval.

f Any of the above considerations may warrant a departure from the standard but departures should only be made with Client approval.

Removal of existing installations

8.2 Mark the position of cuts, to

enable removal, at least 200mm from the estimated outer edge of the frame. Cut positions should be adjusted to encompass any existing cracks, with a clearance of at least 50mm.

8.3 Cut through the full depth of the bound layers, with a circular saw, and remove material to expose the frame along each edge.

8.4 Remove the cover and frame. HSE manual handling guidance means that this will usually require at least two operatives.

Re-use of existing covers and frames.

8.5 Where re-use is permitted, examine cover and frame for damage. If either cover or frame is unfit then the complete unit should be replaced. Previous use of polyester resin will prevent re-use. Any adhering cementitious bedding should be removed prior to the re-use of any frames.

Frame supporting structure.

8.6 The structure should be inspected for integrity.

8.7 All old bedding material must be carefully removed, avoiding dropping loose material into the shaft.

8.8 Consider Health and Safety regulations and Confined Spaces regulations before operatives enter manholes.

8.9 If the previous bedding was polyester resin it will be necessary to remove and rebuild the top layer of the supporting structure to suit the depth of reconstruction. If the structure is brickwork, all joints shall be full and pointed.

8.10 The bedding surface must permit a bedding thickness of between 10mm and 75mm.

8.11 The frame supporting structure must be either class B engineering bricks or pre-cast cover frame and seating rings, laid with proprietary mortar which will develop a minimum 20N/mm2 prior to trafficking. (This requirement will not be readily met by use of OPC and sand mixes)

Re-bedding of Covers/Gully Gratings

8.12 Bedding layers >50mm should be laid in 2 stages. The first layer no thicker than 40mm and must be covered with proprietary packing material while the mortar is workable. The packing should be tamped down to ensure a uniform and even contact with the bedding. Reinstatement of surrounding flexible carriageway

8.13 Once the mortar is set and the cover has been placed in the frame, the bituminous reinstatement should be carried out in accordance with usual patching techniques and subject to the following considerations:

a. The cover and frame should not be exposed to any load or disturbance until the bedding material has attained sufficient strength.

b. Care must be taken to avoid contact between compaction plant and the frame in order to avoid damage to the frame, cover or bedding layer.

c. If compaction plant will not fit between the frame and the reinstatement sides then a self setting material, compatible with the bearing material, should be used.

d. The level of any self setting material used should allow for the specified surface course thickness to be placed. Some materials will require a bonding agent.

e. Vertical faces of frames and existing surfacing shall be painted with hot 50pen bitumen or other approved edge sealing system.

Sub-Appendix 1/5 TESTING FREQUENCIES AND PRODUCT CERTIFICATION (BY THE DEVELOPER) General Requirements 1.1 Tests comparable to those

specified in this Appendix will be necessary for any equivalent work, goods or materials proposed by the Developer.

1.2 Unless otherwise shown in

this Appendix tests for work, goods or materials as scheduled under any one Clause are required for all such work, goods or materials in the Development.

1.3 Cube strength tests are not

required for concrete complying with Clause 2602.

1.4 Unless otherwise shown in

this Appendix tests certificates for work, goods or materials as scheduled under any one Clause are required for all such work, goods or materials in the Development.

1.5 The Appendix refers to mandatory testing. Additional appropriate testing and assessment may be required on a site specific basis; details of any additional work will be agreed with Development Services staff

1.6 Unless otherwise

scheduled under Clause 2603 samples of concrete complying with that Clause are not required.

1.7 Testing which is required to

be carried out by the Director of Development Services may be arranged through:-

Staffordshire Highways Laboratory

Sandyford Street Stafford ST16 3NF Tel; 01785 277360 Fax; 01785 277370 N.B. Clause Numbers in

This Appendix Correspond with those in the HA MCDHW

Table 1/5

00Clause Work, Goods or Material

Test Frequency of Testing

Comments

Earthworks N/A Natural

formation Equilibrium

CBR based on Plasticity testing of cohesive

material or grading of

granular material

1 per material type

sampled from

formation inspection every 30m

N/A Made ground

formation

Equilibrium CBR of natural materials or in-

situ testing of manufactured

granular material

As above for natural

material. In-situ test

every 30m on

manufactured

General fill M/C, MCV, OMC, PI,

Grading

1 per 1000m3

Testing and acceptability parameters

to be agreed with SHL on

a site specific

basis Full MCDHW

table 6/1 testing

1 per source For method compaction

6F2, 6F3, 6F5

Selected Fill Or Grading

and sight of FPC data

where appropriate

supplemented by in-situ CBR

1 per source plus in-situ tests every

30m

Method compaction

procedure still to be followed

600 series

6N Fill to Structures

M/C, OMC, Grading

Field dry density

1 per source 1 per 400t

End product compaction

803 Type 1 sub base

Grading, PI and sight of

FPC data.

Dynamic stiffness

measurement

1 per source

Every 30m

Where adherence

to MCDHW method

compaction can’t be

demonstrated

900

series Asphalt

mixtures Binder content

and grading 1 per source

Compaction of

Asphalt layers

Air void content

3 core pairs for schemes

<1000m2 then pro-rata

Sub-Appendix 1/7 1. Carriageway Construction Materials The County Council is keen to promote environmental sustainability through the use of secondary or recycled aggregates. Developers are, therefore, encouraged to consider ways in which they can minimise the use of primary aggregates. Proposals for construction works, using recycled options, will be considered on an individual basis. 2. Hot Rolled Asphalt Surface Course for Footways Table 1 HRA 45/6 surf 160/220 – proprietary material .

The coarse aggregate shall be crushed rock with a minimum PSV of 50. The binder shall be 160/220 pen bitumen. The material shall be compacted to comply with the air void requirements as specified in Sub-Appendix 1/2 table 2. 3. Recycling of Highway

Materials 3.1 Recycled Granular Material Attention is drawn to amendments to MCDHW which allow the use of recycled aggregate for many classes of unbound granular materials: principally pipe bedding, filter media, capping layer and sub base. It has not been considered necessary to specify these products individually as they are required to comply with relevant clauses of MCDHW and hence their use does not require any exceptional permission or concession.

Chapter 2 BS test sieve (mm)

% by mass of total aggregate passing BS test sieve

10 100 6.3 85 – 100 2 45 – 57

0.500 34 – 57 0.250 10 – 40 0.063 4.0 – 8.0

Maximum % of aggregate passing 2mm

and retained on the 0.500mm test sieves

12

Target binder content % (m/m) of total mixture

6.6

3.2 In-situ Recycled Material in Base In-situ material, recycled in-

place using bitumen, bitumen emulsion, foamed bitumen, cement, lime, pfa, or a combination of these or other binding agents, shall be subject to the proposals being previously agreed with the County Council Development Services Directorate or their representatives. Foamed bitumen usage shall be based on and follow the principles set out in MCDHW clause 948. Targets of 95% confidence levels for the dynamic stiffness and fatigue strength of the in-situ recycled material shall be either previously agreed or agreed, following Joint pilot trials carried out by the Developer and Staffordshire Highways Laboratory (SHL). Sampling plans and testing ages and rates shall be agreed before any work commences on site. SHL will sample and test the recycled material on equally shared cost basis for both the Developer and the County Council.

4. Staffordshire County Council Policy for Use and Specification of Stone Mastic Asphalt (SMA). March 2005

Policy

1. Material Selection 14mm Nominal Size SMA The use of 14mm Nominal

Size SMA should be restricted to high speed sites where a 1.3mm texture depth requirement exists i.e. where the 85 percentile speed exceeds 55 mph. (see Specification for Highway Works clause 921 for Guidance).

There are concerns

regarding the durability and stability of lower pavement layers where 14mm SMA surface course is used. Due to its inherent porosity the use of 14mm material above construction layers which are susceptible to the ingress of moisture should be avoided. In such cases, where a texture depth requirement exists, consideration will need to be given to the provision of a bond coat sealing layer below the 14mm SMA interface. Details are given in BS 594987 cl 5.5.

10mm Nominal Size SMA The use of 10mm Nominal

Size SMA is appropriate on lower speed sites including roundabouts and junctions where a texture depth of 1.0mm is required. The 10mm material has a relatively low porosity and good durability characteristics. However the use of bond coats, as above, may still be prudent.

6mm Nominal Size SMA The use of 6mm SMA is

permitted in heavily used footways but due to potentially very low surface texture should not generally be considered for carriageway use.

2. Early Life Skid Resistance The early life skid resistance

of SMA is a cause for concern due to the presence of significant amounts of surface bitumen which may result in skid resistance values in dry conditions similar to those experienced on “run in” material in wet conditions.

Use of Sealing Grit The use of sealing grit on SMA has been found to provide a significant improvement in early life skid resistance and its use should be specified. However it should be noted that the application of grit will reduce texture depth to some degree – possibly to less than 1.3mm even where 14mm material is used. Therefore, if as a result of a site specific risk assessment, a texture depth > 1.3mm is considered paramount then the gritting process should be omitted. The surface skid resistance should then be measured and “Slippery Road Signs” (Diag. 557 with Supplementary Plate to Diag. 570) should be provided whenever the values fall below HD 28 investigatory levels. The rate of spread of sealing grit should be approximately 0.5 to 0.7 kg/sqm and should be applied by mechanical means to ensure an even rate of spread and to avoid the occurrence of excessive localised accumulations of material. For sites where speeds are restricted to 20 mph or less, early life skid resistance should not be a problem.

On sites where grit has been applied “Slippery Road” signs will not normally be needed and skid resistance tests will only be carried out where there is an accident related problem, or a previously high level of skid resistance which has come to be relied upon by road users. For high speed sites where grit has not been applied the Staffordshire Highways Laboratory should be asked to test the skid resistance at the site after 6 months prior to the removal of the signs to determine that an acceptable level of skid resistance exists. On heavily trafficked sites where the skid resistance may well have reached its desired value within 3 months, a 3 month skid test could be requested. This would have the advantage of avoiding an unnecessary proliferation of signs. In all cases, the aim should be to avoid leaving signs in place after their usefulness has expired to avoid “familiarity breeding contempt”. SPECIFICATION Stone Mastic Asphalt Surface Course 14mm SMA surf 40/60 10mm SMA surf 40/60 6mm SMA surf 40/60 or 100/150 6mm SMA bin 40/60 or 100/150 – for regulating.

1. General 1.1 Stone Mastic Asphalt shall generally comply with the requirements of PD 6691 annex D except where amended by this document. 1.2. 14mm SMA. A general SMA material to be used on all high speed roads in Staffordshire where a texture depth of 1.3mm is required and specified (note, not suitable for roundabouts see 10mm SMA below) - 10mm SMA. A 10mm SMA material, for use on all other roads, including roundabouts, a minimum texture depth of 1.0mm is required and specified. The minimum texture depth may be increased to 1.2mm on a site specific basis. - 6mm SMA. Used in heavily used footways and as carriageway regulating material. 2. Materials 2.1 POLISHED STONE VALUE -

generally not less than 60, but as specified In Appendix 7/1 after reference to HD36/06 table 3.1.

RESISTANCE TO FRAGMENTATION – Category LA30, or as specified in Appendix 7/1.

MAXIMUM AGGREGATE ABRASION VALUE – not more than 12, or as specified in Appendix 7/1 after reference to HD36/06 table 3.2

DURABILITY (WATER ABSORPTION) – Category WA24 or as specified in Appendix 7/1.

2.1.2 When tested in accordance

with the procedures in BSEN 13043, the fine aggregate shall comprise crushed rock or crushed slag fines, which may be blended with not more than 50 percent natural sand.

2.1.3 Added filler shall only be

crushed limestone in accordance with the requirements of BS EN 13043, 5.2.1 and shall be at least 2 percent by mass of total aggregate.

3. Mixture 3.1 The target aggregate grading

and target binder content proposed for the mixture shall fall within the limits given in Table 1, unless agreed otherwise by SHL

3.2 The manufacturer shall carry

out initial type testing in accordance with EN 13108 – 20 in order to demonstrate conformity with EN 13108 – 5 and PD 6691, as amended below.

3.3 Minimum binder content for 14mm SMA shall be Bmin6.0, Bmin 6.4 for 10mm and Bmin 7.0 for 6mm.

3.5 Void content shall be Vmin1.5

and Vmax4 4. Compaction 4.1 Stone mastic asphalt shall be

compacted to practical refusal following the general requirements of BS 594987 cl 9.

4.2 The degree of compaction shall be assessed by extracting 150mm dia cores, at a rate of 6 No cores per 1000 m2. The maximum density shall be determined in accordance with EN 12697 – 5, procedure A, in water. For reference purposes and in the event of dispute the bulk density shall be determined in accordance with EN 12697 – 6 procedure C sealed specimen, for routine purposes the bulk density may be determined in accordance with procedure A, surface dry specimen. The maximum density and core bulk density shall be used to determine air void content in accordance with EN 12697-8. Compliance shall be judged by comparison with the specified air void content shown in table 3.

Core holes will be reinstated by the Contractor. Coring shall be restricted to a trial sections of each pavement or to other areas at the direction of the SHL.

4.3 Each set of six cores will be

taken as 3 sets of 2. The cores from each core pair shall be taken one from each wheel track zone of the finished road pavement. For the purposes of this Clause the wheel track zone shall be taken to be between 0.5m and 1.1m and between 2.55m and 3.15m from the centre of the nearside lane markings for each traffic lane.

5. Surface Texture 5.1 Texture depth as specified in

Appendix 7/1. 5.1.1 10mm SMA material to

achieve a minimum Clause 921 texture depth of 1.0mm or 1.2mm.

5.1.2 14mm SMA material to

achieve the standard Clause 921 texture depth of 1.3mm.

6 Thickness of Material 6.1 Nominal compacted

thickness of14mm and 10mm material shall be 40mm.

6.2 6mm material to be laid in a

layer 25mm thick.

Sub-Appendix 1/10 Highway Works Detail HWP Combined Specification Sub-Appendix 1/11 Surface Levels of Pavement Courses 1. Horizontal Alignments,

Surface Levels and Surface Regularity of Pavement Courses shall comply with the requirements of MCDHW clause 702. For the purposes of this document Distributor roads shall be designated category A roads and all other roads shall be category B.

Sub-Appendix 1/12 Formation Weedkiller Treatment 1 Surfaces shall be sterilised by

the application of a weedkiller. In the case of completed formations, the surface shall be sterilised prior to the laying of sub-base or base material.

Where weedkiller is to be applied to a surface to sterilise it on a permanent basis, prior to superimposing further construction layers, a suitable residual weedkiller shall be used in accordance with the manufacturer’s instructions, in order to prevent weeds growing within the construction surface.

A granular residual herbicide shall be used which contains 6.75% Dicholobenil as the active ingredient, and shall be spread at the rate of 175kg per hectare, or as directed by the manufacturer. The type of weedkiller to be used shall be approved by the County Council prior to its use.

2 The Developers shall ensure that surfaces and vegetation beyond those surfaces to be sterilised do not receive weedkiller. Areas to be treated shall be suitably screened and shall receive measures to prevent animals entering onto treated surfaces being in contact with or consuming treated vegetation. The Developer shall not contaminate any watercourse with the use of weedkillers. The Developer shall display and remove as necessary, appropriate notices to warn the public of hazards from his operations and the treated surfaces.

The Developer shall be responsible for any adverse effects of herbicides on desired vegetation, particularly the effects of drift or seepage onto roadside planting, adjacent trees, shrubs, agricultural crops and gardens.

3 Vegetation removed from the surface to be treated, part used materials and containers, shall be transported and disposed of by approved means, to a licensed tip to be provided by the Developer.

4 The Developer shall take into account the recommendations contained in the Health and Safety Commission Approved Code of Practice “The safe use of pesticides for non-agricultural purposes”.

5 The storage of weed

spraying materials will not be permitted within the highway boundary.

6 Herbicides shall be applied in

carriageway channels to give a maximum treatment width of 300mm, which shall comprise a 150mm width at the front and rear of the kerb face. At the back of the footway, the maximum treatment width shall be 225mm.

7 All spraying equipment must be capable of operating 1m or less above ground level and be of sufficient pressure to produce a coarse spray quality to prevent wind-drift of chemicals.

8 The method of filling the water tanks of the spraying vehicles is to be carried out in accordance with the requirements of the Environment Agency.

Sub Appendix 1/13 Construction Works in the Vicinity of Trees 1. Where it is proposed to

construct highway infrastructure or buildings in the vicinity of trees, then appropriate measures must be taken to ensure that existing trees are not damaged by the construction works and that new or existing trees are not adversely affected during their natural life cycle and, equally importantly, that those trees do not have an adverse effect on the adjacent infrastructure.

2. In preparing proposals for

development work in the vicinity of existing trees, the guidelines and recommendations set out in BS5837 “Guide for Trees in relation to construction” shall be followed. This standard gives guidance on the principles to be applied to achieve a satisfactory juxtaposition of trees, including shrubs and hedges, and structures. Appendix A to the Guide also provides guidance on the most appropriate species for new planting in relation to construction constraints.

3, The criteria which must be addressed in preparing proposals for highway related development works in the vicinity of trees include the following:-

- Effect of leaf deposition - Effect of trees/branches on

visibility - Proximity of vehicles to

trees - Effect of construction works

on root system inc. compaction, soil stripping, oxygen starvation, etc.

- Need to adopt special construction measures to avoid damage to roots

- Need for exclusion zone, to prevent storage of materials and plant

- The age of the trees; in general, the older the tree, the more susceptible it will be to disturbance through changes in the surrounding ground conditions. It is recommended that expert arboricultural advice is sought to assess the effect of construction works on mature tree specimens.

Where young tree specimens are involved, the effect of tree and root growth on the carriageway and footway must be considered.

4. Where it is necessary to construct footways within the curtilage of the trees root system then it will be necessary to adopt a “no-dig” type of construction in carrying out this work, no roots should be severed, soil must not be compacted and oxygen must be able to diffuse into the soil beneath the constructed surface.

5. The construction should

incorporate a high tensile synthetic geogrid overlaid with a layer of granular sub-base with a minimum thickness of 150mm, 6mm – 50mm graded granular sub-base and a porous tarmacadam surface course 60mm in thickness.

6. The edge of the footway

should be a minimum of 0.5m from the trunk of the tree and should be supported by timber edging and retaining pegs. The original ground surface should be stripped of non-woody vegetation only. The maximum depth of excavation should not exceed 100mm.

7. Further details of “no-dig”

construction may be obtained from the Arboricultural and Advisory Information Service, tel. 01420-22022.