Autogenous self-healing of thermally damaged cement paste with carbon nanomaterials subjected to different environmental stimulators

Autogenous self-healing of post-fire damaged concrete enables structure performance auto-recovery leading to reduced repair costs, less generated waste, and lower CO2 emissions. In this paper, improve the efficiency process understand underlying mechanism, 0.1 wt% MWCNT-modified pure cement paste subjected novel environmental stimulators was tested. High-temperature damage induced at 200 °C 400 °C, followed by a cyclic treatment with water, mixture water phosphate-based retarding admixture, limewater. The proposed solutions were compared based on crack closure, strength regains, porosity, chemical composition changes. surface closure after varied between 33% 60%, whereas for only admixture exposure obtained over 50% most considerable decrease in average width paste. highest values compressive recovery, equal 18% 14%, exceeding intact specimen's strength, observed healed Water an extended wetting phase enhanced recovery materials. Strong (r = 0.87) moderate 0.52) positive correlations temperature loading flexural parameters, respectively. Higher porosity interconnected network, caused high temperature, facilitated process. Porosity changes before healing pronounced contrast amount unhydrated cement, which did not exhibit noticeable mechanism included three processes: calcite formation, further hydration inside cracks, rehydration bulk