Experimental investigations on MICP-based autonomous crack-healing recycled aggregate concrete: a sustainable approach for enhancing the strength and durability
Mohd Abu Bakr, Birendra Kumar Singh, Ahmed Hussain
Abstract
Cracks in concrete, including recycled aggregate concrete (RAC), lead to durability issues from substance penetration. This study introduces microbial precipitation for crack healing in RAC. It substitutes 50% and 100% of natural coarse aggregate with recycled coarse aggregate and replaces cement with blends of hydrated lime and brick powder. Self-healing effectiveness is assessed through compressive strength, RCPT, UPV, and microscopic analysis. Results show complete healing of 0.58 mm cracks over 56 days, with compressive strength regain ranging from 94% to 56%. RCPT variation ratios range from 142% to 173%. Microstructural analysis through FESEM, EDS, and XRD reveals microbial precipitate properties. FTIR and TGA analyses explore CaCO3 through infrared absorbance and mass variation with temperature. The study suggests that microbial-induced self-healing improves strength and durability in recycled aggregate concrete.