Bond Properties of Glass Aggregate-Reinforced Concrete after Freeze-Thaw Cycles

This study investigates the bond behavior of glass aggregate-reinforced concrete (GARC) after freeze-thaw cycles, considering a number of freeze-thaw cycles (10, 20, and 30) and fine aggregate replacement rates (25%, 50%, and 75%) as variable parameters. Sixteen groups of specimens were designed to conduct central pullout tests after freeze-thaw cycles, and the bond-slip curves of each group were plotted. The bond performance of the GARC and its failure mechanism after freeze-thaw cycles were examined by analyzing the failure mode, ultimate bond strength, peak displacement, and bond stiffness. The results indicated that freeze-thaw cycles had a deteriorating effect on the bond performance of GARC. However, under the effect of the same number of freeze-thaw cycles, in comparison with the bonding performance of natural aggregate-reinforced concrete, GARC exhibited a higher resistance to the deterioration effect of freeze-thaw cycles, which was enhanced by increasing the replacement rate. In addition, the optimization effect of glass sand on the bonding properties became increasingly prominent as the freeze-thaw cycle deepened. Therefore, after freeze-thaw cycles, GARC exhibited excellent bonding behavior, and 75% GARC exhibited the best bonding performance. Based on the experimental data, considering the number of freeze-thaw cycles and aggregate replacement rate, the bond-slip constitutive equation of GARC after freeze-thaw conditions was established. Glass aggregate-reinforced concrete has excellent resistance to freeze-thaw cycle damage. After freeze-thaw cycles, glass aggregate concrete has better bonding performance with reinforcement than natural aggregate concrete, and the degree of improvement is related to the replacement rate of glass sand. The bond mechanism between the glass aggregate concrete and reinforcement was explained after freeze-thaw cycles. The research results proved the potential capacity and advantages of glass aggregate concrete under a complex environment and demonstrated the research potential of glass aggregate concrete. In addition, this study provided a new approach to improving the resistance of conventional concrete materials to complex environments. By replacing part of the river sand in concrete with glass sand, the resistance of concrete to freeze-thaw cyclic damage could be significantly improved without affecting the mechanical properties of reinforced concrete. This could also effectively address the problem of recycling waste glass and increasing shortage of river sand.