RBSM-based mesoscale study of mechanical properties and frost damage behaviors for recycled fine aggregate concrete

This paper investigates the influence of recycled fine aggregates (RFA) on RFA concrete through a mesoscale approach, mainly focusing on mechanical properties and frost resistance. First, considering the higher water absorption and weaker mechanical performance of RFA, the original Rigid Body Spring Model (RBSM) for normal concrete was modified according to various collected experimental parameters, including porosity, pore size distribution, and basic mechanical parameters. Then, the modified model was applied to analyze frost damage behaviors of RFA concrete and verified with experimental data. Furthermore, the verified model was extended to a wider range of influential factors, such as RFA replacement ratio, water -to -cement ratio, and water absorption ratio of RFA, to obtain a general and quantitative evaluation of frost resistance for RFA concrete. Finally, a probabilistic damage model based on a two -parameter Weibull distribution was constructed to establish a relationship between the life (i.e., the number of freezing -thawing cycles) and key parameters (RFA replacement ratio, water -to -cement ratio, and water absorption of RFA). It is both shown in the experiment and simulation that the frost resistance of RFA concrete decreases significantly as the RFA replacement ratio and RFA water absorption ratio increase, and the water absorption of RFA has a significant effect on the performance of RFA concrete under FTCs.