Development of Engineered Self-Healing and Self-Repairing Concrete-State-of-the-Art Report

Abstract

Challenging studies of engineered self-healing and self-repairing functions in concrete structures are briefly reviewed. While self-healing of concrete has been studied for a long time, it was only recently noticed that some engineered technologies are useful to stimulate the potential of concrete to be self-healed. For example, fiber reinforced cementitious composites (FRCC) have a much higher potential of self-healing than ordinary concrete because of their capability to keep cracks thinner and also because of the bridging network system in cracks; a specific bio-chemical approach, i.e. the application of mineral-precipitating bacteria, is now available; and various mineral admixtures are useful for practical application. Furthermore, the new concept of self-repairing concrete, which is based on the design concept of intelligent materials, is reported. Self-repairing concrete is concrete that incorporates devices for achieving the three key functions of an intelligent material, (1) sensing, (2) processing, and (3) actuating. This paper is a state-of-the-art report on the recent development of engineered self-healing and self-repairing concrete.

Effects of autogenous healing on the recovery of mechanical performance of High Performance Fibre Reinforced Cementitious Composites (HPFRCCs): Part 1

“…As reportedly known since 1836 (French Academy of Sciences) and as also demonstrated by several tailored or "serendipity" studies all along the last century, even ordinary concrete inherently possesses an "autogenous" self-healing capacity due to either delayed hydration of cement/binder or carbonation, or the combination of both [1,2]. As a matter of fact, because such a capacity turned out to be quite randomly scattered and thus neither reliable nor predictable in an engineering application perspective, a paramount effort is currently challenging the concrete research community: "engineering" self-healing capacity of concrete and cement based construction materials.…”

“…The not seldom dramatic deterioration of existing building structures and infrastructures have revamped in the last decade the technical interest and related research efforts on the self-healing capacity of cement-based construction materials [1,2].…”

“…As a matter of fact, because such a capacity turned out to be quite randomly scattered and thus neither reliable nor predictable in an engineering application perspective, a paramount effort is currently challenging the concrete research community: "engineering" self-healing capacity of concrete and cement based construction materials. With that purpose, tailored mix design concepts and related additions are being investigated with the aim of making healing less scattered and hence more reliable, predictable and able to be controlled and regulated as required by the anticipated service and exposure conditions [1][2][3][4].…”

Self-Healing Ability of High-Strength Fibre-Reinforced Concrete with Fly Ash and Crystalline Admixture

“…Autonomous healing is another healing process based on engineering that improves the self-healing properties. Moreover, engineered healing is further classified as 'active' and 'passive' modes [11,12,14]. To activate the active mode, human help is required, but for 'passive' mode, no such help is required.…”

“…Many self-healing approaches, including autogenous, adhesive-based, mineral admixtures-based, and bacteriabased methods, have been developed [7]. There are two mechanisms for self-healing in concrete such as autonomous healing and autogenous healing [10][11][12]. Autogenous healing is a natural process which heals small cracks depending upon the composition of the concrete.…”