Screening of Fungi for Potential Application of Self-Healing Concrete

Abstract

Concrete is susceptible to cracking owing to drying shrinkage, freeze-thaw cycles, delayed ettringite formation, reinforcement corrosion, creep and fatigue, etc. Continuous inspection and maintenance of concrete infrastructure require onerous labor and high costs. If the damaging cracks can heal by themselves without any human interference or intervention, that could be of great attraction. In this study, a novel self-healing approach is investigated, in which fungi are applied to heal cracks in concrete by promoting calcium carbonate precipitation. The goal of this investigation is to discover the most appropriate species of fungi for the application of biogenic crack repair. Our results showed that, despite the significant pH increase owing to the leaching of calcium hydroxide from concrete, Aspergillus nidulans (MAD1445), a pH regulatory mutant, could grow on concrete plates and promote calcium carbonate precipitation.

Microbe‐Mediated Extracellular and Intracellular Mineralization: Environmental, Industrial, and Biotechnological Applications

“…[ 138 ] Filamentous fungi exhibit great potential for the precipitation of calcite and other biomineral crystals. [ 139 ] Cracks within the fungal hyphae contain a thick calcareous coating, which is the nucleation site for the precipitation of calcite. Formation of calcium oxalate proceeds via accumulation of Ca 2+ on the fungi surface.…”

Research on Improving Concrete Durability by Biomineralization Technology

“…With the increase in environmental protection awareness, these environmentally unfriendly repair materials must be eliminated. In addition, the repair effect of these substances is not very significant due to compatibility issues with the concrete substrate, so researchers from various countries have been working toward environmentally friendly and sustainable repair of biological systems [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22].…”

“…Many studies have pointed out that small cracks in concrete can be repaired by themselves based on the continuous hydration of cement or other physical and mechanical behaviors [5,6,10,11,13,14]. In the field of concrete science, this phenomenon is often called "autogenous healing" or "concrete self-healing."…”

“…Therefore, biomineralization can often form an ordered natural organic-inorganic composite material with excellent structure. In view of this, in recent years, microbiologically induced calcium carbonate precipitation (MICP) technology based on microbial mineralization has become a hot topic in concrete self-healing technology and has attracted widespread attention in the academic community [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23].…”

“…Many published studies have confirmed that calcium carbonate precipitates produced by bacteria have been successfully used to repair concrete or limestone surfaces, and that they significantly increase the strength or durability of concrete [6][7][8][10][11][12]15,16]. However, in essence, the bacteria in these studies were applied externally to cracked concrete structures or specimens.…”