Experimental Study on Durability and Mechanical Properties of Lightweight Mortar with Encapsulated Spore Forming Bacteria

Abstract

Concrete is a material that is used worldwide for centuries as a construction material. Increased consumption of concrete leads to vulnerability of structure physically, chemically and biologically. Exposure to extreme conditions and detrimental effects of corrosion of reinforcements leads to cracking of concrete. Compressive strength, Flexural strength, and permeability can be affected by these cracks consequently leading to shortening the useful life of the concrete. Repairing and maintenance of these infrastructures need higher cement consumption and expenses. The benefits of microbial concrete can reduce the consumption of cement for structural replacements and maintenance works. Self-healing concrete by microbially induced calcite precipitating bacteria is an economical and sustainable solution, as it autonomously repairs small cracks. In this paper, we discuss the mechanism and performance of bio-concrete along with the idea of microbially induced calcite precipitation (MICP). The Bacillus species is proven to be an effective microbial agent for self-healing concrete. Hence the sample preparation is done using encapsulated spore-forming Bacillus Subtilis bacteria species as a biological healing agent. Three concentrations of 105, 107, and 109 cells per millilitre are adopted for sample preparation. The mix proportion of cement mortar is 1:3, using expanded perlite as a replacement for the fine aggregate in the percentages 10% was done. The mechanical and durable properties of bio-mortar are evaluated to ascertain the possibility of the same as a resilient building material. © 2023, The Author(s), under exclusive license to Springer Nature Switzerland AG.