BIO-HEALING OF GENERATED CRACKS IN ROCK MASS USING ENZYME

Abstract

Rock masses in tunnels, slopes, foundations and underground excavations are highly susceptible to crack development caused by blasting, excavation, weathering and repeated mechanical loading, which compromises their strength, permeability and long-term stability. Conventional repair techniques such as cement grouting and epoxy injection are costly, environmentally damaging and often ineffective for fine or inaccessible cracks. This study investigates Enzyme-Induced Carbonate Precipitation (EICP) as a sustainable, bio-based alternative for healing artificially generated cracks in rock specimens. Rock core samples retrieved from a field borehole were characterized for their physical properties, after which artificial cracks were induced and treated with an enzyme healing solution containing urease, urea and calcium chloride. The treated specimens were cured under controlled conditions to allow calcium carbonate precipitation within the crack network. Post-treatment evaluation included measurements of weight change, density, water absorption, crack width closure and Uniaxial Compressive Strength (UCS) recovery, which were compared against untreated cracked specimens. The results demonstrate that EICP treatment produced measurable healing efficiency, with enzyme-induced calcium carbonate deposits sealing crack surfaces, reducing permeability and restoring a significant portion of the original compressive strength. These findings confirm that enzyme-based bio-healing offers a viable, eco-friendly and cost-effective approach for repairing damaged rock masses in geotechnical and underground engineering applications, with potential for further validation over longer curing durations and varied rock types. The other serval application of EICP in tunnel stabilization, Sustainable rock engineering and foundation improvement.