The Transport Scotland Pavement Forum (TSPF) promotes and develops best practice and knowledge sharing for the management and maintenance of Scottish trunk roads.
The TSPF was formed in 2007 to address problems with the surface layer of roads including durability, cost effectiveness and workmanship. Due to the success and popularity of the Forum within the Scottish road maintenance community, the remit was broadened in 2010 to cover all aspects of road pavement design, construction and maintenance, including materials, drainage and innovation.
Transport Scotland Pavement Forum: Terms of Reference
The TSPF meets quarterly and member organisations include:
- Transport Scotland
- Scottish Trunk Road Operating Companies
- Mineral Products Association
- Society of Chief Officers of Transportation in Scotland (SCOTS)
- Office of the Scottish Road Works Commissioner
- Road Design Consultants
- WSP (Secretariat)
- The Institute of Asphalt Technology
The Forum provides an opportunity for specific studies and research to be shared with the road maintenance community and acts as a crucible for the creation and promulgation of new ideas. Accordingly, the Forum has facilitated a number of developments including the following:-
Formation of the Scottish Inspection Panel
The Scottish Inspection Panel (SIP) consists of a team of road engineers that annually inspect sections of the trunk road network that were resurfaced as maintenance schemes around two years earlier, in order to assess how they are performing. This allows us to assess not only the quality of the material used but also the workmanship and laying techniques employed. We can also consider other aspects which are not directly pavement related but can have an impact on the road pavement, for example drainage. The team identifies recurring issues which are then raised at the TSPF for focussed attention and the development of corrective action plans. Where a concern has been identified, subsequent SIP inspections are undertaken to evaluate the effectiveness of the action plans.
The 2018 surface inspection was carried out in September 2018 and results show an improvement in the quality of work being carried out in the trunk road network Scottish Inspection Panel Report 2018. The inspection revealed a measurable difference in the quality of both the materials used and of the workmanship, as evident in aspects such as tighter construction joints and denser asphalt. This will lead to more durable surfaces resulting in improved value for money and reduced disruption to road users over the long term.
Development of a new surfacing material - TS2010
In 2010, Transport Scotland published a specification for a new road surfacing material, known as TS2010. The development of the specification was led by a technical team within Transport Scotland following a period of extended research. The Transport Scotland Pavement Forum acted as a vital sounding board by providing peer review and challenge to this process and continues to do so under an arrangement of continuous review.
TS2010 Specification and Guidance
TS2010 is more durable than traditional thin surfacing materials and is therefore Transport Scotland’s surfacing material of choice. TS2010 has been used on several major construction projects, including on the new approach roads to the Forth bridges and on the Queensferry Crossing. Results from the Scottish Inspection Panel indicate that the material is performing as expected and is on track to achieve a service life of around double that of previously used materials.
Trial of new products and systems
New systems and products which are trialled on the trunk road network are reported to the TSPF, which provides a valuable peer review function and scrutiny of the output. Trials to date have included the use of recycled tyre rubber in roads and the use of additives in road materials to make them easier to compact and reduce CO2 emissions.
Formation of Road Recycling Subgroup
In 2019 it was noted in the Pavement Forum that recycling of road materials was becoming more important particularly as a way to re-use life expired roads containing Coal Tar. This is because the recycling processes effectively encapsulate the Coal Tar within the new binding agents. In order to encourage and control reuse of these materials a Road Recycling subgroup was instigated. Members were drawn from the Pavement Forum and recycling practitioners. Through collaborative working of the group a guidance document has been written:
An Approach to Cold Recycling of Bitumen and Tar bound Roads
It is hoped that this will be adopted by the wider roads community in Scotland.
Measurement of road and outdoor sports surfaces foundations
The Light Weight Deflectometer (LWD) is a device that plays a vital role in checking the quality of road foundations and base installations for sports facilities, such as football pitches and athletic tracks. It was brought to the Pavement Forum that there was no system for control and correlation of LWD machines used for this purpose. Therefore through the Pavement Forum Transport Scotland commissioned WSP in partnership with National Highways and AECOM, to assess the performance of LWD devices operating in the UK. The report gives full details of the correlation trial findings.