A review of novel self-healing concrete technologies

Cracks and damage of concrete during service pose threats to its safety and durability. Compared to traditional repair techniques, self-healing strategy for concrete repair is regarded as a promising technology. This paper reviews the recent advancement in concrete self-healing. It primarily outlines various mechanisms and required repair materials for concrete self-healing. Two self-healing techniques, namely microcapsule self-healing and microbial self-healing, are highlighted. Internal and external factors influencing the effectiveness of concrete self-healing, characterization methods for self-healing effectiveness, and engineering applications are summarized and discussed in this paper. The combination of multiple self-healing techniques can yield excellent self-healing effect compared with the single technique. The maximum crack healing width by the microorganisms and microcapsules was 970 μm. However, most of the current self-healing research remains at the laboratory stage, the composite self-healing techniques should consider practical conditions and cost factors, and their self-healing mechansiums should also be investigated detailedly. Standardization and regulation of self-healing test methods are necessary to facilitate the development of new self-healing concrete materials and technologies.