Durability restoration of cementitious composites via micro encapsulated mineral repair agents

This research proposes and evaluates an embedded self-sustained restoration system based on the trigger-release of microencapsulated repair agents within the concrete matrix. Micron-sized polymeric capsules carrying a mineral based repair agent were designed to rupture upon stress build-up, releasing the enclosed compound that set and bridged the formed cracks. Cementitious prisms incorporating microcapsules were subjected to controlled cracking and subsequently submerged in water to facilitate the self-repair process. Compressive, flexural strength and permeability tests were performed to evaluate crack width restoration and durability recovery. Two different mass fractions, i.e. 1% and 5% microcapsules/cement ratios were investigated to assess the effects on repair efficiency. The effect of age at crack onset was also considered. The healing products were isolated and characterised through SEM, TGA and XRD. Results were promising on the use of colloidal silica as a repair material for durability restoration of cementitious composites.