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

[Display omitted] •A new self-healing concept is explored, in which fungi are used fill concrete cracks.•An initial screening of different species of fungi has been conducted.•Trichoderma reesei was found to be able to grow equally well with or without concrete.•Trichoderma reesei can promote the formation and precipitation of CaCO3. The goal of this study is to explore a new self-healing concept in which fungi are used as a self-healing agent to promote calcium mineral precipitation to fill the cracks in concrete. An initial screening of different species of fungi has been conducted. Fungal growth medium was overlaid onto cured concrete plate. Mycelial discs were aseptically deposited at the plate center. The results showed that, due to the dissolving of Ca(OH)2 from concrete, the pH of the growth medium increased from its original value of 6.5 to 13.0. Despite the drastic pH increase, Trichoderma reesei (ATCC13631) spores germinated into hyphal mycelium and grew equally well with or without concrete. X-ray diffraction (XRD) and scanning electron microscope (SEM) confirmed that the crystals precipitated on the fungal hyphae were composed of calcite. These results indicate that T. reesei has great potential to be used in bio-based self-healing concrete for sustainable infrastructure.