Experimental study on bio-concrete for sustainable construction

Abstract

Concrete, a widely used building material, is highly susceptible to cracking, significantly reducing its lifespan and leading to expensive repairs. Cracks may occur in both the plastic and hardened stages due to various reasons such as formwork movement, plastic settlement, weathering, drying shrinkage, and thermal stress, among others. While it is impossible to prevent cracks from occurring, there are several techniques available for repairing them. However, some of these methods, such as the use of chemicals and polymers, have been found to be harmful to both human health and the environment, and they only provide temporary solutions. Alternatively, microbial self-healing concrete has been shown to be a promising approach, due to its compatibility with concrete and effective bonding ability. Self-healing concrete or bacterial concrete is a type of concrete that can repair structural flaws by filling them with bacteria that cause a biological reaction that seals the crack. Microbial concrete is a sustainable solution to reduce and repair concrete cracks compared to passive treatments such as chemical sealants which have several limitations. This article provides an overview of the microbiological methods employed for manufacturing calcium carbonate, which is used in microbial crack therapy. It was observed that the compressive strength of biomimicry concrete was found to be greater than ordinary concrete. It yields 15% greater value than control concrete for split tensile strength test. The flexural strength was found to be 30% more than control concrete. It has also been found that it has the capability to withstand larger strain, i.e., even after the formation of cracks, the specimens did not collapse. The paper also discusses the potential issues associated with this technique and offers suggestions for further research.