Effect of Polymer-based Self-healing Agent on the Gas Permeability of Cement Mortar After Compressive Loading

Abstract

Concrete is easily to crack due to its low tensile strength. Once harmful substances ingress through cracks, the service life of concrete will be endangered. The self-healing agent with a high healing efficiency and multiple autonomous is prepared based on pyrogallol and polyethylenimine. This self-healing agent is in liquid state, when the solution is exposed to air, there will be a film formed at the liquid/air interface. This film exhibited well regenerative properties which can be used to seal the cracks of concrete to reduce the risk of ingress of aggressive substances. In this paper, the ratio of the two components of the self-healing agent was investigated to achieve an optimization of strength and generation rate of this film. Then cement mortar specimens of Ф100×50 mm are immersed in the self-healing agent under a vacuum environment to let the pores fill with self-healing agent. Thereafter, the discs are subjected to gas permeability test to exam the effects of self-healing agent on the permeability of cement mortar before and after compressive loadings. Results showed that this material can effectively reduce the gas permeability coefficient of cement mortar with micro cracks. Scanning electron microscopy (SEM) results also confirmed the crack barrier effect of this self-healing agent. Through several loading cycles, this self-healing agent also retained a certain self-healing effect in cement matrix, indicating that this self-healing agent appears to be a promising approach to increase concrete durability.