ABSTRACT
When recycled aggregate concrete (RAC) reaches its service life in freeze-thaw environment, it is critical to consider how to reuse it for the sustainable development of civil engineering. This paper studied the frost resistance of RAC with different strength grades (C40, C50, and C60) and explored the performance index (apparent density, water absorption, crushing value, aggregate output rate, and adhesive mortar content) of the second-generation recycled coarse aggregate (2nd-RCA). Results showed that the relative dynamic elastic modulus of RAC with three different strength grades decreased after the freeze-thaw cycles. When the number of freeze-thaw cycles reached 400, the relative dynamic elastic modulus of C60 was the highest with 75%. According to the performance of 2nd-RCA produced by C40, C50, and C60, all three groups of 2nd-RCA can meet the grade III coarse aggregate standard, indicating the recyclability in a freeze-thaw environment. It is possible to use C40 concrete in an area with few freeze-thaw cycles, C50 and C60 are recommended when the freeze-thaw cycles are excessive.
