Study of natural self-healing of hydraulic concrete damaged by up to 200 freeze-thaw cycles

To investigate the recovery effect of natural self-healing of freeze-thaw damage of cementitious material-poor hydraulic concrete, we carried out a natural self-healing test for hydraulic concrete damaged by up to 200 rapid freeze-thaw cycles. The self-healing effect of macro-mechanical properties of hydraulic concrete damaged by freeze-thaw cycles was quantitatively characterized by the recovery rate of the specimens which underwent different numbers of freeze-thaw cycles then continued the standard curing to 28 days. Next, the microscopic properties of damaged hydraulic concrete after self-healing were further investigated by combining XRD, SEM and nitrogen adsorption tests. Finally, a prediction model of the recovery rate of macro-mechanical properties was established by using the microscopic pore test results. The results showed that, when the hydraulic concrete undergoes the damage of different freeze-thaw cycles and continues to standard curing for 28 days, the concrete specimens manifest natural self-healing to some extent even if damaged by up to 200 freeze-thaw cycles.