Demonstrating the potential of biological self-healing for conservation through the healing masonry prototype

The option to heal our built environment, as an alternative to new construction, has the potential to become a more ethical approach. The Healing Masonry prototype investigates the application of emergent biological self-healing systems to masonry materials. It seeks to engage a wider audience in the repair of the built environment, specifically historic environments, and aims to go beyond demonstrating mechanical performance and durability to explore the visual communication of processes that are otherwise invisible through an exhibited installation at the HBBE experimental house, the OME. Red lime mortar samples, either with smooth surfaces or imprinted patterns were treated with Sporosarcina pasteurii to induce biomineralisation. After seven healing cycles, a stable deposit of calcium carbonate was observed on the surface. Following further cycles, sequential increase in calcium carbonate precipitation was observed along with a gradual colour change from red to white. For units with surface textures, calcium carbonate deposition initially occurred in the fissures. All cube modules have been displayed to highlight surface textures and colour variation. Each unit can be rotated and demounted for further inspection. The results indicate biomineralisation has the potential to heal damage and protect materials from further deterioration, while preserving marks of cultural significance. Current and future work focuses on improving the biological process efficiency, application methods, tailoring self-healing to respond to different stimuli, and exploiting engineering biology to develop genetic toolkits that enhance MICP production in Sporosarcina. Engagement activities with external stakeholders and qualitative data collection will continue to take place in the OME, through workshops and public open days.