Fungal-Induced Biomineralisation for Concrete Repair

Nuclear sites comprise huge volumes of concrete assets, which are exposed to differing environmental conditions resulting in variable mechanisms, and rates of, concrete degradation. For example, external concrete building facades may be exposed to freeze-thaw and high salinity, whereas some internal concrete structures may be exposed to high temperatures and high levels of radiation.

This project is focused on developing a novel technology for repair of concrete on nuclear sites. Traditional and established methods for concrete repair, disposal and decontamination are expensive, time-consuming and can result in the spread of contaminated particulates over large areas. Biomineral technologies are: non-destructive (no excavation is required); durable; and can significantly inhibit radionuclide migration.

In recent years there has been significant interest in bacterially-induced mineralisation for concrete repair. The overall aim of this PhD project is to assess the feasibility of deploying fungal-induced biomineralisation (FIB) for the treatment and repair of degraded concrete. Fungal-based strategies could potentially have a number of advantages over bacterial-based strategies including: improved uniformity of treatment, reduced number of treatment cycles, improved mechanical strength and reduced costs associated with transporting/cultivating microorganisms.

The objectives of this PhD are to:

1. Investigate different fungal-induced biomineralisation pathways (e.g. precipitation of calcium carbonates, calcium oxalates and phosphate minerals). The most promising of these pathways will be selected for further investigation in Objectives 2 and 3. Key drivers in the selection process will include the fungal growth rate, time required for mineral precipitation and the total mass of biomineral that can be precipitated.

2. Investigate the influence of fungal growth duration and treatment strategy on the spatial distribution of (i) the fungal network created and (ii) the resulting biominerals precipitated.

3. Investigate the hydraulic and mechanical behaviour of concrete repaired via fungal-induced biomineralization. Experiments will investigate the influence of fungal growth duration and treatment strategy on permeability and compressive and tensile strength.