Industrial Application of Biological Self-healing Concrete: Challenges and Economical Feasibility
Self-healing concrete has been scrutinized by several researchers and some industrial concrete producers in relation to the remediation of the occurrence of micro-cracks. Such cracks are a quite well known problem that can lead to corrosion of the steel reinforcement and thus to the possible failure of the entire concrete structure. The need to repair these cracks as soon as possible leads to maintenance costs which can be of the order of €130 (direct costs) per m3 of concrete. Recent scientific studies indicate that a Microbial Induced Carbonate Precipitation (MICP), using microbial spores as active agent, can be an alternative for the actual repair methods. However, the production of bacterial spores is yet imposing considerable costs. According to some concrete producers they would be willing to pay about €15 to €20 per m3 of concrete for a bio-based self-healing product. However, the actual cost of spores production and encapsulation represent a total cost which is orders of magnitude higher. This article analyzes the costs for the biological self-healing in concrete and evaluates the industrial challenges it faces. There is an urgent need to develop the production of a bio-additive at much lower costs to make the biological self-healing industrial applicable. Axenic production and a possible non-axenic process to obtain ureolytic spores were analyzed and the costs calculations are presented in this paper.