Self-healing bacteria concrete: an approach for sustainable crack repair for Ethiopian construction industry

Abstract

Cracking is a natural phenomenon in concrete under ageing, exposure to severe cli-mate conditions and under certain loading conditions in a structure. There are sev-eral methods which are available for crack repair that are mostly labor intensive and not cost-effective. Sporosarcina Pasteurii bacteria which is a common type of bacte-ria found in soil when exposed to air produces calcium carbonate around its body. This mechanism can certainly be helpful for auto healing the cracks in concrete when these bacteria are used in the concrete mixing process. Few research has shown that these bacteria have the ability to fill the cracks when used in concrete. In essence, this paper presents the mechanical and durability properties evaluation of concrete when mixed with bacteria. Compressive strength and tensile strength have been in-vestigated from a mechanical properties perspective and resistance to acid attack, water desorption, carbonation and effect of high temperature have been studied as part of the durability investigation. The experimental results revealed that, there was no negative effect of bacteria on the compressive strength of concrete however the tensile strength showed an improvement by 10%. The durability test results revealed that the resistance of bacteria concrete to water desorption, acids attack, carbona-tion and high temperature enhanced compared to controlled concrete and the opti-mum percentage of bacteria was found to be 3%. So, bacteria concrete can certainly be used as a crack healing measure in concrete for a cost effective and sustainable approach for Ethiopian construction industry.