Industrial Application of Biological Self-healing Concrete: Challenges and Economical Feasibility

Abstract

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.

A Review of Self‐Healing Concrete for Damage Management of Structures

“…Silva et al calculated an operational expense cost (OPEX) of more than 400 € kg −1 of bioagent for the production of axenic ureolytic spores, a cost that was highly affected by the need for sterile production conditions . Nonaxenic (nonsterile) production of ureolytic bacterial spores would allow to reduce production costs.…”

Interactions of fungi with concrete: Significant importance for bio-based self-healing concrete

“…So far there has been little success with respect to the long-term healing efficacy and in-depth consolidation, mainly due to the limited survivability and calcinogenic ability of the bacteria. Furthermore, from the economical point of view, the production of bacteria-based self-healing concrete currently results in considerable costs due to the need of aseptic conditions to produce the microbial spores and the use of expensive growth media, making this approach unlikely to be applied in practical applications 33 . In summary, there are still huge challenges to bring an efficient self-healing product to the concrete market with the guaranty that this product can both attain legislative requirements and be costeffective.…”

Microbially Induced Calcium Carbonate Precipitation (MICP) and Its Potential in Bioconcrete: Microbiological and Molecular Concepts

“…These factors cause microcracks formation, which affect mechanical and durability properties of concrete such as compressive strength, flexural strength, and permeability, consequently reducing the useful life of concrete and increasing the cost of the maintenance and repair of infrastructures. Although the global cost of concrete production ranges between e 60/m 3 to e 75/m 3 , the average cost for crack repair in Europe is about e 130/ m 3 (Silva et al, 2015), which reveals the high cost involved in the maintenance and repair of concrete structures. In the last two decades, incorporation of a bacterial metabolic process known as Microbially Induced Calcium Carbonate Precipitation (MICP) has emerged as an alternative method to reduce the cost and environmental impact.…”