Guidance document on surfacing options …

1 Guidance document on surfacing options for Highways 2010 Edition Technical Advice Group Hampshire County Council Capital House Andover Road Winchester Hampshire SO23 7BH HAMPSHIRE COUNTY COUNCIL ENVIRONMENT DEPARTMENT TECHNICAL ADVICE GROUP Guidance document ON surfacing options FOR HIGHWAYS CONTENTS Page Number 1 2 3 surfacing Preliminary Effect of Existing Substrate on Material Overlay or Inlay?..4 Inter-layer Quality Materials Testing Strategy (MTS)..6 Layer Thicknesses and Weather Considerations for Hot Applied Deferred Set Traffic 4 SELECTION OF AGGREGATES AND Aggregate Aggregate Selection for Surface 5 SELECTION OF APPROPRIATE surfacing Relative Properties of surfacing Guidance on Choice of Sites with a Speed Limit of 40 mph or Sites with a Speed Limit of Less than 40 Detailed Consideration Of Alternative surfacing 6 SURFACE Surface Dressing on Surface Dressing on 7 REHABILITATION OF THE EXISTING Pothole Repairs and Reinstatements Within Special Crack Sealing Asphalt 8 ROAD In-situ Ex-Situ Recycling ( Cold Recycled Bituminous Bound)

2 Material)..56 9 CONCRETE SLAB Exposed 10 HIGH FRICTION AND DECORATIVE High Friction Surfacings (decorative surfacings derived from HFS systems)..58 Coloured 'Gateway' Surfacings - Resin Bonded Resin Bound Decorative 11 BLOCK PAVING AND NATURAL STONE General Block Paving for Vehicular Block Paving for Pedestrian Block Paving for Shared Improving Skid/Slip Natural Stone 12 ASPHALT REINFORCEMENT Choice of Grid Thermal Cracking with some anticipated Vertical Displacement Clay Shrinkage Concrete Joint problems/severe Clay Shrinkage Guide to Successful 13 General A note on Slurry Treatment of APPENDIX A.

3 PERMITTED PAVEMENT Appendix 7/1 Appendix 7/1 Appendix 7/1 Appendix 7/1 Appendix 7/1 Appendix 7/1 Appendix 7/1 Appendix 7/1 Appendix 7/1 Appendix 7/1 Appendix 7/1 Appendix 7/1 APPENDIX B : KEY CHANGES SINCE 2002 Revised Bituminous Material New Materials and Page 1 of 101 Published April 2010 1 INTRODUCTION The last 50 years have seen significant changes to road legislation and automotive technology. Higher traffic loadings now impose greater stresses on road materials and have highlighted some weaknesses in traditional surfacing materials. There is a need now also to consider the sustainable use of materials and the potential influence of climate change on the future performance of materials.

4 The highways industry has responded by both improving the specification and properties of traditional materials and by developing new surfacings However, there is no one surfacing material that is "perfect" for all applications and some, whilst ideal in certain circumstances, would be totally unsuitable in others. Additionally, the costs between materials can vary significantly. Purpose of this document The purpose of this document (first published in February 1989) is to provide Highway Engineers with Guidance on the various highway surfacing materials/products on the market so that the most suitable and cost-effective material is selected on a site specific basis.

5 As far as is possible, all the Guidance is based upon practical experience both within Hampshire and nationally. The Highway & Transport Branch strongly support the use of environmentally sustainable or 'green' alternatives to conventional maintenance operations. Many 'green' solutions are now incorporated into standard maintenance treatments. This document aims to provide Engineers with a combination of information, advice, Guidance and Departmental policies/standards. All Guidance / information is given in normal type and Engineers are encouraged to use their judgement on a scheme specific basis. All text in bold type, however, are requirements with which Engineers must comply unless a departure has been agreed at SMG level in advance.

6 The requirements noted are generally due to National/County Standards or because specialist advice is crucial to obtain a satisfactory product and for ' best value' in the particular activity concerned. Failure to comply with these requirements could produce sub-standard works and possibly even leave the County liable to legal action. Since the previous edition of this document there have been numerous changes to Standards, Specifications, Materials and Practice and it is these changes which have prompted this revised edition. Many staff will already be familiar with the changes and it is not necessary to know the full detail in order to use this document . Accordingly these are not dwelled upon but have been summarised as Appendix B for those new staff who may appreciate the background.

7 Page 2 of 101 Published April 2010 . Both the Highways and Transport Branch Management Team and the Highways Technical Group (formerly Departmental Standards Committee) have endorsed this document prior to publication. This heavily revised edition has only been published after a comprehensive internal consultation process. However, it is recognised that the document may contain errors, omissions, contradictions, etc. It is also likely that particular scenarios may not be covered. For these reasons, feedback from Engineers (both positive and constructively negative!) would be welcome. Any such feedback should be sent to the Technical Advice Group - Tel.

8 01962 845735, Fax. 01962 854045 or email 2 SCOPE Whilst this document has been formulated primarily as a guide to the selection of surface treatments for highway maintenance works in areas not subject to special requirements, the concepts are equally valid for new works in similar areas. The document complements but is not intended to replace The Highways Environment - Design guidelines for Special Areas or Traditional Materials a guide to the use of natural materials in the Highway , both of which remain current and should be referred to when considering surfacing works in special areas . The purpose of this document is to provide sufficient Guidance for Engineers to enable them to specify safe and durable surface treatments which will give an adequate level of performance over their service life.

9 Reconstruction and similar treatments are generally outside the scope of this document and hence materials primarily involved in such operations ( Base and sub-base) are not covered. Eight basic groups of surface treatment are covered: Bituminous surfacings - HRA, AC, Thin Surface Courses, SMA, etc. Surface dressing Rehabilitation of existing surfacing Road recycling Treatment of concrete roads Special surfacings (High Friction surfacing , Coloured surfacing , etc) Block paving and Natural Stone Paving. Footway surfacings Flow charts are used to guide users to the most appropriate group for any given maintenance scenario. Within each group, the merits of a range of possible treatments are discussed and the preferred option is suggested for any particular set of circumstances.

10 In all cases the preferred option has been selected for its engineering properties. Page 3 of 101 Published April 2010 However, there may well be over-riding environmental conditions which will affect the choice of treatment/material Conservation Areas. The intention is that this document should have a long life and therefore no attempt has been made to quantify prices. Prices can be influenced by many factors and specifiers are encouraged to evaluate prices at scheme level. Prices for most of the processes covered will be available through the Term Highway Contract. 3 surfacing GENERAL Preliminary Works Whilst all the materials quoted should perform adequately under the circumstances discussed, it should be borne in mind that any surfacing /surface treatment is only as good as the base upon which it is laid.