67 / 2022-04-06 17:01:10

Novel mineral-based capsule that using SAP as an expansion agent for self-healing concrete

Self-healing, Cementitious capsules, Swelling agent, Concrete

Self-healing technology has been proven to be an effective means to improve the durability of concrete. In this study, a novel type of mineral-based self-healing mechanism with ion binding and crack filling capacity was designed and prepared for the automatic healing of cracks in concrete. The healing agent consists of a mixture of calcium sulfoaluminate cement(CSA), gypsum(CA), and expansion agent superabsorbent polymer (SAP). A multi-layers waterproofing shell was employed to encapsulate and protect the healing agent from being defunctionalized before the cracking. The survival rate of the capsule was investigated in simulated pore solution and real test block. The degree of crack healing was evaluated by the recovery of mechanical properties, water absorption and the change of apparent width. The healing products of capsules were characterized by XRD and TG. The test results implied that the proposed self-healing mechanism can be used as an ideal option for revitalizing the performance of cracked concrete.