Application of bacteria in concrete: a critical evaluation of the current status

Abstract

Microbially induced carbonate precipitation has been tested over more than a decade as a technique to enhance concrete properties. Mainly bacteria following the pathways of urea decomposition, oxidation of organic acids, or nitrate reduction have been studied for this purpose. For bacteria mixed into fresh concrete, it is difficult to prove that they actively contribute to calcium carbonate precipitation and the effects on concrete strength are variable. Application of bacteria for surface consolidation has been shown to reduce water absorption and increase durability. Microbial self-healing of cracks in concrete shows promising results at the laboratory scale. Especially the use of self-protected mixed cultures opens perspectives for practical application. However, their self-healing efficiency needs to be further proven in larger concrete elements, and under non-ideal conditions. The use of denitrifying cultures for concurrent self-healing and production of corrosion inhibiting nitrites is a promising new strategy.

Nitrite producing bacteria inhibit reinforcement bar corrosion in cementitious materials

“…The self-healing control tested in this study was significant to reveal the sole effect of microbial induced crack healing on the corrosion behaviour of the steel. Obtained results revealed that only biomineralization is not an effective method for protection of the steel reinforcement as opposed to the claims in previous microbe-based self-healing studies 4–6,9,14 . Corrosion of the steel reinforcement in self-healing control continued even after the noted complete crack closure on day 28.…”

“…Such regain in functionality is desired to hinder the ingress of aforementioned aggressive substances and to protect the good state of the rebar 11–13 . In previous microbe-based self-healing studies, it was claimed that biomineralization in microcracks is an effective method for protection of the steel reinforcement 4–6,9,14 . Yet, available data lacks solid evidence on the protective effect of MSCC against rebar corrosion.…”

Bacteria-based self-healing concrete: evaluation of full scale demonstrator projects

“…Limestone, or calcium carbonate, is a concrete compatible material that is perfectly suitable for sealing (waterproofing) of cracks in concrete. Several research groups worldwide have developed bacteria-based healing agents to enhance the self-healing capacity of cement pasts, mortars and concrete [7][8][9][10][11][12]. Pioneering and lab-based research by the Delft research group has shown that lactate-based organic compounds like calcium lactate and lactide-polymers) are suitable carbon sources for the bacteria and that these compounds are furthermore concrete compatible in the sense that they as additive, within limits, do not negatively affect strength development of concrete [7, 8 13,14].…”

Preliminary research for identification of bacteria useful in microbially induced calcium carbonate precipitation

“…It is possible to lower the cost of the method by optimizing the concentration of urease and carbonate. However, calcium carbonate is hygroscopic, which triggers high probability of damage in the stone [8].…”

“…Microbially induced calcium carbonate precipitation (MICP) in environmental engineering has been studied mainly for crack remediation in concrete, soil improvement and application in the fields of surface protection of natural stone [8]. MICP as a new technique in engineering is better than conventional chemical methods, which are environmentally harmful, often toxic and expensive [1,7].…”