Influencing Factors on the Healing Performance of Microcapsule Self-Healing Concrete

The amounts of the components in a microcapsule self-healing system significantly impact the basic performance and self-healing performance of concrete. In this paper, an orthogonal experimental design is used to investigate the healing performance of microcapsule self-healing concrete under different pre-damage loads. The strength recovery performance and sound speed recovery performance under extensive damage are analyzed. The optimum factor combination of the microcapsule self-healing concrete is obtained. Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) are carried out on the concrete samples before and after healing to determine the healing mechanism. The results show that the healing effect of self-healing concrete decreases with an increase in the pre-damage load, and the sound speed recovery rate increases with an increase in the damage degree. The influence of the sodium silicate content on the compressive strength and compressive strength recovery rate of the self-healing concrete increases, followed by a decrease. The optimum combination of factors of the microcapsule self-healing system is 3% microcapsules, 30% sodium silicate, and 15% sodium fluosilicate. The results can be used for the design and preparation of self-healing concrete.