This summer saw publication of ‘Service life of surface treatments’ guidelines that have been developed jointly with local authority chief officers body ADEPT to provide an agreed service life for surface dressing, slurry surfacing incorporating microsurfacing and high friction surfacing. Howard Robinson says: “The guidelines come at a very opportune moment as local authorities have to produce lifecycle plans for their highway assets and report annual depreciation in the Whole of Government Accounts.
“They have been produced by industry experts and should be regarded as being the definitive view of the durability of surface treatments.”
New codes of practice covering surface dressing, high friction surfacing, and retexturing have been published this summer jointly with ADEPT. More new codes for slurry surfacing, geosynthetics and steel meshes, structural recycling techniques and patching solutions are expected to be published this autumn. A code on preservation techniques is being updated for publication at the end of this year. A new carbon calculator for surface treatments has recently been developed jointly by RSTA and the University of Nottingham. A number of seminars part funded by Construction Skills Management Leadership Development programme are planned for this autumn to roll out these new tools. Codes can be downloaded from www.rsta-uk.org/publications.htm
The new surface dressing code, endorsed by ADEPT, provides a comprehensive library of technical guidance and best practice. The document provides a full and in depth explanation of surface dressing and the key issues that must be addressed such as health and safety, the environment, training, site planning, equipment and installation.
There are guidance notes on types and design of surface dressings, binders, aggregates, road surface preparation, when to surface dress and guidance on the use of spray tankers.
High friction surfacing
The high friction surfacing code is endorsed by ADEPT and the Road Safety Marking Association.
High friction surfacing (HFS) significantly improves the skid resistance of roads and is particularly useful on approaches to pelican crossings, roundabouts, junctions and crossings as well as bends with a radius of tighter than 500m on single carriageways. Use of HFS can result in a 35% reduction in accidents.
The code examines both hot and cold processes in detail and provides best practice guidance and technical specification for their selection and application.
Surface retexturing offers a quick and cost effective way of maintaining skid resistant road surfaces by restoring their micro and/or macro texture. The speed and efficiency of the technique significantly minimises works duration and, therefore, traffic disruption.
For the best results it is essential to ensure that the correct retexturing technique is used. Techniques include: bush hammering; grooving/grinding; longitudinal scabbling; orthogonal grooving and water jetting. The Code explains which technique is most suitable for which road surface.
The code underlines the need for early contractor involvement to ensure the choice of the most appropriate treatment and provides technical information on the appropriate circumstances and treatments for retexturing bitumen bound and concrete road surfaces.
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