Evaluation of Self-Healing Properties of Mortar Containing Microencapsulated Epoxy Resin

Under the complex environment of soils, rocks and underground water, the challenges in the repair and maintenance of urban metro structures confront engineers daily. The use of microcapsule-enabled self-healing cementitious composite has high potential as a new repair method for cracked concrete under complex service conditions. The benefit of using microcapsule-enabled self-healing cementitious composite will evidently provide extended durability, service life and security for the metro tunnels. In this study, the self-healing microcapsules enclosing epoxy resins as the adhesive agent are embedded in mortar to achieve the self-healing capability. The properties of healing agents are investigated. The microcapsules are observed by SEM (scanning electron microscope) to obtain the micrographs. The self-healing efficiency is assessed by mechanical restoration of the damaging specimens. The four-point bending test is used. The influence of the content of microcapsules and initial damage is investigated. The results demonstrate that the microcapsule-containing mortar can achieve the mechanical restorations depending on the content of microcapsules and initial damage. Some conclusions about the healing agents and the shell are drawn.