Professor Rebecca Lunn, University of Strathclyde

Maintaining and developing our national infrastructure comes with substantial financial and environmental costs. Industry deploys construction techniques that have changed little over decades, require the transportation of large volumes of carbon-intensive construction materials and produce significant waste streams. Through this Royal Academy of Engineering Chair, I aim to deliver low-carbon technologies to the construction industry that harness natural biochemical mineralization processes to provide reliable engineering solutions.

There is a rapidly growing interest in biologically-induced mineral precipitation for the repair and enhancement of civil engineering structures. These technologies inject specific bacteria, alongside a fluid containing selected mineral salts and nutrients. The bacteria metabolise the nutrient and a by-product of the reaction is mineral precipitation. The most well studied of these systems is microbially induced calcite precipitation which utilises natural soil bacteria to precipitate calcium carbonate. The precipitated biominerals can be used to strengthen soils, turning loose sand into weak sandstone, or to seal fractured rocks/damaged building materials to make them ‘water-tight’. Biomineral technologies are: non-destructive - they are injected in-situ; the minerals formed are durable in the natural environment; and they can form a low-carbon alternative to traditional cement-based solutions. At present, biomineral technologies are largely confined to the laboratory, although a small number of field trials (De Jong et al. 2013) and commercial applications are emerging (BIOCALCIS, Esnault Filet et al. 2012; Self-healing concrete, Jonkers, 2015). However, these applications remain bespoke, and significant research and development is required before biomineral technologies form an accepted, large-scale alternative to traditional construction methods.