Mechanical properties of recycled aggregate concrete under cyclic loading and unloading in alpine areas

This paper focuses on the mechanical properties of recycled aggregate concrete under cyclic loading and unloading conditions after freezing and thawing in alpine regions. The differences in the properties of recycled aggregate concrete and ordinary concrete, including the residual deformation characteristics under cyclic loading and unloading, hysteresis loop characteristics, elastic-plastic deformation, and the damage characteristics introduced based on the energy method, are comparatively analyzed. Experimental results show the final damage variables of the RC50 specimens increased by 1.82%, -0.83%, and -0.66% at 0, 25, and 50 cycles of freezing and thawing, respectively, compared to the NC specimens, which indicates the RC50 specimens have better resistance to cyclic unloading damage when the number of freezing and thawing cycles is less than 50. The RC50 and NC specimens perform similarly, whereas the RC100 specimens exhibit irregularity in the late stages of cyclic loading and unloading and freeze-thaw cycles.