Characterising the resilient behaviour of pavement subgrade with construction and demolition waste under Freeze-Thaw cycles

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 en-hances 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 attenu-ation 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. ? 2021 Elsevier Ltd. All rights reserved.