Bacteria-based Self-Healing Concrete− A Life Cycle Assessment Perspective

A life cycle assessment (LCA) was utilised to evaluate the environmental impact of bacteria-based self-healing concretes (BBSHCs), where non-ureolytic bacterial endospores are encapsulated in porous calcium silicate granules. Findings reveal that 1 m3 of BBSHC has an overall 85% higher environmental impact than equivalent conventional concrete, primarily due to calcium nitrate and polyvinyl acetate. Furthermore, BBSHC has a 36% larger embodied carbon footprint (120 kg CO2 eq) and a 51% larger water footprint (260 L). However, by selectively incorporating BBSHC in specific areas of reinforced concrete structures, leveraging its inherent self-healing properties to deliberately allow wider crack widths, and consequently, reduce the amount of non-structural steel needed to control early-age cracking, sustainability improvements ranging from 12% to 50% can be achieved depending on the impact category. In this regard, a BBSHC-structure can potentially save up to 51 kg CO2 eq per m3.