Effect of chemical composition of polymeric precursors on the healing capability of cementitious materials

Cracking in concrete is frequently a concern since these cracks can provide easy entry channels for the penetration of aggressive liquids and gases into the concrete, leading to deterioration. The repair of these cracks is, therefore, indispensable. However, manual crack repair is expensive and difficult when cracks are not visible or accessible. Thus, the design of concrete with self-healing properties would be highly beneficial to improve its durability. One of the crack repair approaches makes use of capsules sequestering polymer-based healing agents. The self-healing mechanism is triggered upon crack formation, leading to release and reaction of the healing agent in the zone of damage. In the present work, we aimed at determining the most suitable polymer backbone to be applied for self-healing of cementitious materials. For this purpose, several key prerequisites such as viscosity, curing time and mechanical properties of different polymeric precursors including siloxane-, urethane-, epoxy- and polyester-based have been evaluated. To assess the effect of high alkalinity on the degradation of the polymerized healing agents, stability tests have been performed. The results indicate that different healing agent solutions show adequate curing time, viscosity and mechanical properties. The various healing agent solutions were manually injected into cracks of mortar samples to evaluate their sealing capability and strain capacity