Strength properties of self-healing mortars

Abstract

Cementitious materials are the most widely used in building materials all over the world. However, deterioration is inevitable even since in the very beginning of the service life. In addition, the maintenance and repair work which are often labor- and capital-intensive, would be followed. Thus, self-healing of the affected cementitious materials is of great importance. Self-healing phenomenon in cementitious materials has been noticed and been studied for a long time. Self-healing of micro cracks by introducing bacteria at the time of formation of mortar or concrete is gaining momentum these days. However presumably self-healing with polymeric admixtures might be relatively more durable and faster process. The development and characteristics of self-healing synthetic polymeric materials have been inspired by biological systems in which damage triggers an autonomic healing response. This is an emerging and fascinating area of research that could significantly extend the working life and safety of the polymeric components for a broad range of applications. In this research an epoxy resin (diglycidyl ether of bisphenol A) without any hardener is used as polymeric admixture to prepare polymeric-cementitious materials and their self-healing function is evaluated. Epoxy-modified mortars are prepared with various polymer-cement ratios subjected to initial wet/dry curing plus long term dry curing and tested for strength properties. The fundamental properties such as workability, influence of curing, strengths, strength development, porosity, permeability and water absorption are investigated. The ultrasonic pulse velocity (UPV) and compressive strength test were conducted to determine the ability of self-healing of Mortar by used liquid polymer. The result shows that 10% of polymer is the best percentages of polymer - cement and wet dry curing was the best mechanism to heal the hairline crack in mortar.