Abstract: In the aim of assessing the impact of different compound salt solution concentrations on the frost resistance of recycled aggregate concrete (RAC), we conducted freeze-thaw cycle tests on RAC samples by varying the concentration of the compound salt solution, the strength grades, and the number of freeze-thaw cycles. We scrutinized apparent damage, mass loss rate, splitting tensile strength loss rate, cubic compressive strength loss rate, and relative dynamic elastic modulus loss rate. Our findings reveal that higher strength grades correlate with better salt-frost resistance in RAC. After 30 cycles, mass loss, compressive strength and splitting and tensile strength loss, as well as relative dynamic elastic modulus loss decrease with increasing concentration of compound salt solution. However, after 90 cycles, salt-frost damage escalates with rising solution concentration. We established exponential function and Weibull distribution salt-frost damage models for RAC in consideration of the solution concentration and strength grades. Comparison manifests that the survival function graph and failure rate fuction rendered from Weibull distribution model better describe the salt frost damage level and efficiency. Moreover, the Weibull distribution model result aligns well with experimental results from other scholars.

Key words: recycled aggregate concrete, compound salt solution cncentration, salt-frost cycle, mechanical properties, Weibull distribution function, damage model