Research progress on microbial self-healing concrete

Abstract

Crack formation in concrete is inevitable. The cracks allow the penetration of harmful substances which may decrease the durability and the service life of concrete structures. Self-healing concrete is therefore emerging as an innovative construction material to tackle the cracking issues. In recent years, microbial self-healing concrete is garnering interest from many researchers due to its environmentally-friendly nature and the concrete compatibility of microbially-induced calcium carbonate precipitation. Various metabolic mechanisms have been used for microbial self-healing concrete production and urea hydrolysis is the most preferable metabolic pathway due to its fast and high precipitation of calcium carbonate. In this paper, a comprehensive review on the research progress on microbial self-healing concrete is presented together with the numerical modelling of microbial self-healing concrete. The challenges and limitations of microbial self-healing concrete are discussed along with the recommendations for its prospective uses in the construction industry. It is found that the survival of bacteria through direct addition technique is limited and needs further investigation. The immobilization technique gives a promising result in durability properties but doesn’t reach the mechanical requirement. Moreover, a comprehensive assessment of self-healing efficiency is required, and more efforts are needed to improve from laboratory scale to large-scaled application.