Tests and Numerical Studies on Strain-Rate Effect on Compressive Strength of Recycled Aggregate Concrete

In this study, the compressive strength of recycled aggregate concrete (RAC) was investigated by conducting quasi-static and split Hopkinson pressure bar (SHPB) tests. Three types of RAC specimens with recycled coarse aggregate (RCA) replacement percentages (i.e., 30%, 70%, and 100%) and the natural aggregate concrete (NAC) specimen as reference were prepared and tested. Failure modes of the specimens were observed and compared, and dynamic compressive strength was recorded. The effect of different RCA replacement percentages on the compressive strength under quasi-static and dynamic loads was studied. The empirical formulae were proposed for dynamic increase factor (DIF) of the compressive strength for RAC. In this study, the DIF of compressive strength raises with the rising RCA replacement percentage. Besides, the continuous surface cap model (CSCM) is developed by considering strain rate effect for RAC material, and its accuracy is calibrated with the SHPB testing data by using LS-DYNA. The numerical results show that CSCM incorporating strain rate effect can yield more accurate prediction on dynamic compressive strength of RAC.