Experimental and numerical investigation on freeze-thaw performance of high-volume mineral admixture self-compacting concrete

The utilization of industrial by-products, such as fly ash (FA) and silica fume (SF), instead of cement to produce self-compacting concrete (SCC) has been demonstrated to result in a substantial reduction in the amount of cement used. In this paper, SCC was prepared using high-volume mineral admixtures (HVMA-SCC) with 40%, 50%, and 60% replacement of FA and SF, respectively. Test results indicate that at 40% mineral admixture content, increasing SF from 5% to 15% reduced the mass loss rate by approximately 36% after 200 cycles, increased the relative dynamic modulus by 6.7%, and decreased the damage degree by about 34%. When SF = 10%, each 10% increase in FA reduced the relative dynamic modulus by approximately 10% after 100 freeze-thaw cycles. Comprehensive evaluation indicates that after undergoing 200 freeze-thaw cycles, F25S15 demonstrated optimal performance, exhibiting the lowest mass loss rate of 1.52% and the highest relative dynamic modulus retention rate of 87%, and the total mineral admixture content should not exceed 50%. Furthermore, a discrete element model for HVMA-SCC considering freeze-thaw damage was proposed. The simulated results indicate that the bonding in the model was mainly subjected to tensile damage, which was consistent with the experimental situation of cement mortar being subjected to tensile fracture damage during freeze-thaw cycles. The numerical simulation's development pattern for the freeze-thaw damage degree matched the findings of the experiment, showing error ranges between 0.02% and 3.49%.