Study on Autogenous Self-Healing Concrete Using Crystalline Admixtures

Abstract

The shrinkage, thermal changes and external loadings of concrete structures can cause cracking, leading to increased water and aggressive agent penetration and deterioration and shortened service life. A sustainable solution to mitigate crack propagation has been found to be autogenous self-healing utilizing the inherent healing properties of cementitious materials. Most of the self-healing methods have received extensive research interest, especially crystalline admixtures which encourage the growth of non-soluble crystalline products to seal cracks and enhance the impermeability of concrete. This study focuses on the effectiveness of the crystalline admixture to improve self-healing capacity of concrete. The concrete specimens were formed having various doses of crystalline admixtures and the specimens were subjected to a controlled crack creation in a laboratory environment. After a curing period, the healing criteria for the appearance of cracks, recovery of compressive strength, reduction of water permeability, sorptivity and ultrasonic pulse velocity testing were applied. The experimental results show that the use of crystalline admixtures show significant enhancement in crack closure as well as improvement of mechanical and durability properties of concrete, compared to conventional concrete. Concrete containing crystalline admixtures exhibited higher healing efficiency, higher strength recovery, less water penetration, less sorptivity and improved internal concrete integrity. The results suggested that use of crystalline admixtures could be considered a viable and eco-friendly option to prolong the service life of concrete structures and decrease maintenance efforts and life cycle costs. Thus, the proposed solution has a great potential for the development of long-term and sustainable smart infrastructure applications.