Chloride transport and intelligent repair processes in microencapsulated self-healing concrete: A review

Chloride ingress and the resulting steel corrosion are primary contributors to deteriorating concrete durability. Self-healing technology is promising for enhancing concrete durability. Compared to other repair techniques, the microcapsule self-healing technology offers convenient preparation, easy dispersion, and effective repair outcomes. Substantial research has been conducted on microencapsulated self-healing concrete (MSHC). However, systematic reviews on the repair and chloride transport mechanisms in MSHC are lacking. This paper reviews the characterization methods, influencing factors, and modification methods for the repair process of MSHC and describes chloride transportation and detection in MSHC. The results demonstrate that simulation techniques such as X-ray computed tomography (XCT), finite element analysis, and molecular dynamics provide valuable insights for analyzing the repair process of MSHC. The repair performance of MSHC is primarily influenced by the characteristics of the microcapsules and the service environment. Incorporating nanoparticles or using multilayered microcapsules can enhance the mechanical properties and repair performance of microcapsules in MSHC. The ingress of chlorides in MSHC can be quantified by integrating experimental and numerical simulation methodologies. Moreover, chloride erosion resistance in MSHC can be enhanced by improving the repair efficiency of microcapsules and the performance of cracks and interfacial transition zones. •The microcapsules’ characteristics and environment affect MSHC's repair performance.•Microcapsules with nanoparticles or multilayers have enhanced mechanical properties.•Triggering and binding mechanisms of chloride in MSHC can be achieved using ions.•Numerical simulation helps to quantify the ingress behavior of chloride in MSHC.