Dynamic Compressive Performance of Recycled Concrete Considering the Effects of Pretreatment of Recycled Coarse Aggregate and Calcium Leaching

Abstract To promote the resource utilization of construction solid waste and realize the sustainable development of building materials, it is an effective way to develop the recycled aggregate concrete. This study first examined the pretreatment effect of 5% water glass solution on recycled coarse aggregates (RCAs) by soaking them for varying durations. Then, the dynamic compressive performance tests were conducted on the pretreated recycled coarse aggregate concrete (PRCAC) using the split Hopkinson pressure bar device, considering the effects of the soaking duration of RCAs, the incorporation ratio of pretreated RCAs (PRCAs), and the calcium leaching. The results indicate that the water glass treatment improves the pore structure of RCA, reducing its water absorption, crushing index, and porosity. After 12 h of soaking in the water glass solution, the water absorption, crushing index, and porosity of RCA decreased by 13.7%, 11.3%, and 11.2%, respectively. Dynamic compressive strength and dynamic increase factor (DIF) of PRCAC are sensitive to strain rate, and increase with the increase of the strain rate. The dynamic compressive strength of PRCAC exhibits a positive correlation with the incorporation ratio of PRCAs and a negative correlation with the duration of calcium leaching. Additionally, the sensitivity of PRCAC to strain rate is negatively correlated with the incorporation ratio of PRCA and positively correlated with leaching duration. As the soaking duration of RCAs increases, the dynamic compressive strength of PRCAC first increases and then decreases. The degree of strength degradation of PRCAC due to calcium leaching decreases as the soaking duration of RCAs increases. The above research findings contribute to the improvement of the performance of recycled concrete and the correct evaluation of its dynamic mechanical properties.