Nanomaterials based self-healing concrete

Abstract

Concrete after water is the second most-consumed material on this earth. Concrete consists of cement, sand, aggregate and water. It is cheaper, can resist high compressive stress and moulded in a variety of shapes. In general cement materials, in aggressive environments, have very low resistance and durability and service life deteriorate. Due to aggressive environment expansion and cracking of concrete may be enhanced. As a result, microcracks are generated, which shortens the life of buildings. Now, a new concrete known as self-healing concrete, is coming up, which contains fibres or capsules, containing some adhesive liquids. When cracks occur, the fibres or capsules break and the liquid present, heal the crack. During the last years researches have been done on the use of nanomaterials (NMs) in enhancing the healing capability of concretes. Due to advances in the field of nanoscience, self-healing materials have taken new shape. Number of NMs such as nano-silica (n-SiO2), carbon nano-tubes (CNTs), nano-clays, nano calcium carbonate (n-CaCO3), and many other nano-sized materials are being used as healing agents in concretes. However, only a limited studies on the use of NMs in enhancing the self-healing properties of concretes have been made. So, the mechanism of action of NMs as self- healing agent is not been fully understood. This article summarises the latest contributions in the area of NMs based self-healing concrete with mechanistic point of view.