Stress-strain behaviour and pore structure of microcapsule-based self-healing cementitious composite under triaxial tests

In this study, the physical triggered self-healing cementitious composites were prepared by mixing the epoxy resin based microcapsules with the cement, and its mechanical properties and microstructure were investigated as well. The effects of the different content of the microcapsules, proportion of prepressing stress, confining pressure and curing days on the mechanical parameters and microstructure of cementitious composite were carried out by the triaxial compression test and the mercury intrusion porosimetry (MIP) tests. The results indicated that the strength, cohesion, internal friction angle of specimens gradually decreased with an increase in microcapsules content or with an increasing of preloading stress, and the deterioration degree gradually increased with an increase in the microcapsule content or the preloading stress, but peak strain increased to vary degree. The mechanical parameters of the healed samples were repaired to different degrees compared with damaged samples. Microcapsules have significant and positive influences on the healing rates and recovery rates of mechanical properties, pore structure. The healing effect of cementitious materials was improved with increasing microcapsule content. However, the effects of microcapsules on microstructure of sound samples has to be considered. (C) 2020 Elsevier Ltd. All rights reserved.