Surface consolidation of natural stone materials using microbial induced calcite precipitation

Purpose – Deterioration in natural stone is associated with many decay mechanisms and often the inherent composition of the materials themselves. Sandstone varies considerably but they all require a cementing matrix to bind amongst others, the silica (SiO2) particles together (Reading, 1989). In calcareous sandstones and limestones this binding matrix is principally calcium carbonate based (Muir, 2006; Reading, 1989; McMillan et al., 1999) in the form of calcite (CaCO3). Friable sandstone substrates and stones suffering from “surface dissolution” or disaggregation (Muir, 2006; Smith et al., 1992) have been traditionally consolidated utilising a host of chemical compounds that had, in many cases negative effects on their long-term performance (Muir, 2006). A principle issue amongst many was moisture entrapment and irreversibility of the consolidants adopted. The paper aims to discuss these issues. Design/methodology/approach – This paper investigates the effect of microbial induced calcite precipitation (M...