Song Bo

Study on Test Methods for Mechanical Properties of Semi-rigid Base Cores of In-service Pavements

Compressive strength and compressive resilience modulus are two important parameters to measure the mechanical properties of semi-rigid base. The test methods of semi-rigid base cores are different from those of the laboratory samples in terms of sample acquisition, sample selection and humidity requirements. Core-drilling location, size of core sample, smoothness and humidity conditions were analyzed. The test methods of compressive strength and compressive resilience modulus were proposed. The research results show that compressive strength of lime fly-ash stabilized gravels base has a tendency of increasing during a long period. The compressive resilience modulus increases significantly with compressive strength of semi-rigid base. The compressive resilience modulus generally is 3-4 times than the recommended range of asphalt pavement design specifications. The fluctuation range of compressive resilience modulus is obviously higher than the compressive strength. The compressive resilience modulus is more sensitive to the construction variability. The overall trend between the compressive resilience modulus and the back-calculation modulus is consistent. FWD (falling weight deflectometer) back-calculation modulus can reflect the stiffness and bearing capacity of asphalt pavement. Ker words: Road engineering, semi-rigid base cores, compressive strength, compressive resilience modulus, test methods.