Study on aggregate interlock behavior of pre-cracked recycled aggregate concrete without stirrups

In this study, experiments on pre-cracked push-off specimens without stirrups were conducted to analyze the aggregate interlock behavior of recycled aggregate concrete (RAC). The major variables considered in this study were the surface roughness, recycled coarse aggregate (RCA) replacement ratio, concrete strength, aggregate particle size and loading rate. Experimental results indicate that the roughness of the fracture surface relating to the ratio of aggregate fracture significantly affects the shear stress of pre-cracked push-off specimens. The findings reveal that the RCA replacement ratio has adverse effects on the macro-roughness and the aggregate interlock behavior of RAC. The increasing concrete strength leads to a decrease in the surface roughness and the aggregate interlock capacity of RAC. The inferior properties of RCA contribute to decreasing the aggregate interlock behavior of RAC specimens with larger RCA particles. The influence of the loading rate on the aggregate interlock behavior of RAC is insignificant with the increase from 0.06 mm/min to 0.6 mm/min.