Simplified crack, seat and overlay design for Scottish roads

In the 1970s the use of flexible composite road construction became popular in the UK and around 20% of the existing Scottish road network comprises pavements constructed with a lower cement bound material (CBM) overlaid with asphalt. In Scotland, structural maintenance of this type of pavement has typically entailed reconstruction. More recently, however, the crack, seat and overlay (CSO) and rubblisation processes have been shown to offer cost-effective sustainable alternatives. Ongoing research funded by Transport for Scotland to promote the use of sustainable techniques and the development of a new simplified design approach is described. Examples of schemes that have delivered substantial reductions on carbon dioxide equivalent emissions are given. The current design process is reviewed and the weaknesses of the present method are discussed. A partnering approach between Transport Scotland, Scotland Transerv and TRL to develop a new simplified approach is described. The new design model will be based on information collected from previous CSO schemes and validated against the existing method in planned future CSO schemes. It is intended that the model will make use of falling weight deflectometer (FWD) and other technical data used in the design and validation of previous schemes. It is anticipated that the new method will be more flexible and versatile allowing variation in thicknesses, materials and traffic to be easily accommodated. The method will make better use of FWD measurement taken before and after construction, and consideration of more recent design developments regarding foundation classes and pre-cracked hydraulically bound materials.

• Authors:
  • MCHALE, M J
  • LANGDALE, P
  • GUTHRIE, S
  • GORDON, M
• Publication Date: 2010

Language

• English

Media Info

• Pagination: CR026
• Serial:
  • TRL STAFF PAPERS
  • Publisher: TRL

Subject/Index Terms

• TRT Terms: Carbon dioxide; Pavement design; Rigid pavements; Structural strengthening; Surfacing
• Uncontrolled Terms: Rear
• ITRD Terms: 7393: Carbon dioxide; 3096: Overlay; 3055: Pavement design; 9067: Rear; 2953: Semi rigid pavement; 2972: Surfacing
• Subject Areas: Highways; Pavements; I15: Environment; I22: Design of Pavements, Railways and Guideways; I31: Bituminous Binders and Materials; I61: Equipment and Maintenance Methods;

Filing Info

• Accession Number: 01174589
• Record Type: Publication
• Source Agency: TRL
• Files: ITRD
• Created Date: Sep 30 2010 11:15AM