Efficiency of self-healing cementitious materials with encapsulated polyurethane to reduce water ingress through cracks

Cracks in reinforced concrete elements can cause major durability issues due do the accelerated ingress of aggressive substances. In this study, repair of cracks was addressed by incorporating encapsulated polyurethane based healing agents in the cementitious material as an autonomous healing mechanism. Capillary sorption tests showed that a high viscosity healing agent could reduce the water ingress in cracked mortar, but a large scatter in the results was found, resulting in a large range of healing efficiencies (18 – 108%). The low viscosity polyurethane showed a more complete and consistent crack healing. Healing efficiencies ranging from 95 to 124% were observed (crack width up to 295 μm). The proposed healing mechanism is very effective in blocking the ingress of water. This will enhance the durability of cementitious materials and consequently extend their lifetime.