Behaviour of ultra-thin continuously reinforced concrete pavements under moving axle loads

Abstract

Concrete pavements are typically considered to be rigid pavements and are designed using principles based on the beam-on-elastic support equations as derived by Westergaard in 1926. Ultra-Thin Continuously Reinforced Concrete Pavements (UTCRCP) have been constructed with concrete layers as thin as 40 mm. These pavements have been subjected to millions of load cycles without any noticeable damage. The design of these flexible concrete pavements has proven to be problematic as they are neither rigid nor truly flexible. To investigate the response of UTCRCP to traffic loading, a geotechnical centrifuge was used to test UTCRCP scale models at 10G. The results showed that the centrifugal forces had a significant effect on the stiffness of the scaled model. It was observed that the interaction between the substructure and flexible concrete layer differed notably from the assumed behaviour of both rigid and flexible pavements. When designing UTCRCP, not only the loading pattern caused by the interaction between the wheels on an axle and adjacent axles, but also the rutting of the substructure that results in the concrete layer spanning across gaps below it, causing increased vertical pressure between wheel paths, should be considered.