New CRCP Designs in the UK

The paper presents the main findings of a 3-year project to develop new designs and specifications for continuously reinforced concrete pavement (CRCP). The performance and design parameters investigated were surface cracking, the concrete strength, and the foundation. The effects of these parameters on the structural integrity and durability of CRCP were assessed and the results were used to develop new thickness design curves. It was found that the aggregate type in a CRCP has more influence on the crack pattern than the subbase type. Locating the reinforcement at one third of the slab depth gives a significantly better crack pattern in CRCP made with siliceous gravel. A review of international standards and practices has shown the widespread use of flexural strength rather than compressive strength for design purposes. Reliable relationships between flexural and compressive strength were established. These were used to develop new CRCP designs with thinner slabs for higher strength concrete. The cemented subbase layer under CRCP, as previously specified in the UK, has a significantly higher strength than that used in other countries. These new designs consider the new UK foundation classes, which have a range of subgrade strength and use a wider range of hydraulically bound materials. This could result in significant economic benefits.