The effect of concrete strength and fibre content on the fatigue performance of Ultra Thin Continuously Reinforced Concrete Pavement (UTCRCP)

Abstract

Ultra Thin Continuously Reinforced Concrete Pavement (UTCRCP) is an innovative road paving technology that can have significant advantages over traditional road paving techniques. Full scale testing has shown that UTCRCP can carry in excess of one hundred million E80s (standard 80 kN axle loads). The concrete used for the construction of UTCRCP is high strength and contains steel fibres. The purpose of this study is to investigate the effect of varying the concrete strength and fibre content on the mechanical properties of the concrete used to construct UTCRCP. In this study testing is restricted to laboratory methods. Fibre reinforced concrete is often tested with the same tests as those used for plain concrete. These are not adequate to fully capture the effects of the steel fibres. A number of test methods are used in this study and their suitability and shortcomings are discussed. Additionally, fatigue tests are conducted and a number of performance measures are used to track the fatigue damage. It was found that higher concrete strength and high fibre content did not necessarily result in highest performance in all cases. It was also found that there is not a single concrete strength or fibre content that always results in the optimum performance in all cases. For example the concrete strength and fibre content that produced the best results for tensile strength was not the best mix for energy absorption at high deflections. When selecting the concrete strength and fibre content for use in construction the application of the concrete element must be carefully understood. Based on this the designer can then select which of the concrete performance characteristics are of most importance to the desired application. Once this is done an appropriate concrete strength and fibre content can be selected.