Healing the Infrastructure: Bio concrete as a Sustainable Frontier for the Circular Economy A Review

Abstract

The best thing about concrete is that it’s the backbone of modern infra, but it can crack because of
environmental or mechanical pressure. These cracks threaten the longevity and integrity of the
building by allowing water and corrosive fluids to penetrate. The objective of this study is to
examine how Microbiologically Induced Carbonate Precipitation (MICP) aims at production of
"self-healing" bio concrete as an environmentally friendly solution. We study the incorporation of
nutrient precursors, namely calcium lactate and alkaliphilic microorganisms (predominantly from
Bacillus species) into the concrete matrix. The methods described in this article provide protective
encapsulation for bacterial spores during the high-pH mixing process. These include hydrogels,
bio-based polymers, melamine-based microcapsules, and nano-encapsulation. Bio-concrete can
even be able to improve about 95% tensile strength by comparing to the autogenous healing
method in repairing of crack ranges from 0.5mm -1.0mm, according to a recent study. In addition,
MICP use is proven in increasing compressive strength and water impermeability for up to 40%,
gaining the infrastructure with a service life of 50 years to over 100 years. Even though bio
concrete utilization and industrial by-products for bacterial activation is a revolutionary step
toward concepts of the circular economy, still the issues with bacteria activation dependency,
precursor price and homogeneity exist. For wide application to engineering, future studies should
transfer focus on genetic modifications of highly alkaliphilic bacteria and low-cost feeding
substrates.