Effect of freeze–thaw and wetting–drying cycles on the CBR, shear strength, stiffness and permanent deformation of crushed waste rocks

Waste rocks produced from mining operations are widely reused for the construction of mine haul roads. However, seasonal changes expose mining facilities to repeated freeze–thaw and wetting–drying cycles which can significantly affect the geotechnical characteristics of the materials in situ. In this study, cyclic and monotonic triaxial and California bearing ratio (CBR) tests were conducted to measure the geotechnical properties of crushed waste rocks subjected to freeze–thaw and wetting–drying cycles. Results showed that freeze–thaw cycles caused a reduction of the resilient modulus and shear strength, and an increase of the permanent deformation. A greater water content during freeze–thaw cycles resulted in a significant increase of the permanent deformation. Wetting–drying cycles could contribute to increase the stiffness, CBR and permanent deformation of crushed waste rocks. Predictive models were also developed to estimate the effect of freeze–thaw cycles on resilient modulus and permanent deformation.