Autogenous self-healing of cement with expansive minerals-I: Impact in early age crack healing

Abstract

This study investigates the impact of expansive minerals, namely magnesium oxide, bentonite clay, and quicklime on the early age autogenous self-healing capacity of Portland cement (PC) paste. Individual mineral dosage in PC was studied comprehensively together with several multiple mineral combinations. The study also covers a brief state of the art on autogenous self-healing and the use of minerals. The healing performance was compared using flexural strength recovery, crack sealing, and permeability tests. Materials microstructural investigations were carried out using XRD, TGA and SEM-EDX. The hydrated and swelling products of expansive minerals have effectively contributed to the production of healing materials. Cracks in the range of 150 µm healed efficiently in a mineral containing mixes within 28 days. Self-healing recovery was triggered through the crack bridging (strength recovery), sealing (physical closer of cracks through crystallisation) and durability performance improvement.