Characterising the resilient behaviour of pavement subgrade with construction and demolition waste under Freeze–Thaw cycles. (1st June 2021) - Zhang, Junhui
Abstract: Recycling construction and demolition (C&D) waste as fillers in pavement subgrade is a sustainable paving technology with environmental and economic merits. The performance of pavement subgrade with C&D waste depends on its dynamic resilient modulus. Meanwhile, freeze–thaw cycles are also an important issue for engineering in seasonal frozen regions. However, research on characteristics of the dynamic resilient modulus of C&D waste, especially the properties under freeze–thaw cycles, is limited. To this end, this study aims to reveal the variation law of the dynamic resilient modulus of C&D waste under repeated freeze–thaw cycles and establish a reasonable performance prediction model. This study conducts a series of laboratory tests after various freeze–thaw cycles. Results indicate that the soil–water characteristic curves of C&D waste with different compactness and number of freeze–thaw cycles can be well described by Van Genuchten's model. Moreover, the dynamic resilient modulus enhances with the increase of matric suction, compactness, deviator stress and minimum bulk stress and exhibits a stress-hardening characteristic. Freeze–thaw cycles attenuate the matric suction and dynamic resilient modulus of C&D waste. Besides, high moisture contents, low stress levels and more freeze–thaw cycles all aggravate the attenuation of the dynamic resilient modulus in certain extent, but the attenuation is not sensitive to the compactness. Finally, this study establishes a high-accuracy prediction model of the dynamic resilient modulus considering the effect of repeated freeze–thaw cycles. This study can supply useful information on the application of C&D waste in pavement subgrade in seasonal frozen regions. Highlights: Basic performance tests, filter paper tests and dynamic triaxial tests were undertaken. The soil–water characteristic curves of construction and demolition waste subjected to freeze–thaw cycles were described. Effects of freeze–thaw cycles, compactness, matric suction, and stress states on the dynamic resilient modulus were analysed. An excellent model for the dynamic resilient modulus of construction and demolition waste under freeze–thaw cycles was built.