Performance Evaluation of Rice Husk Ash Incorporated Multi-Bacterial Self-Healing Concrete for Enhanced Mechanical Properties, Durability, and Crack-Healing Efficiency

Abstract

Shrinkage, mechanical loading and environmental exposure are common causes of cracking in concrete structures, leading to increased permeability, corrosion of the reinforcement, and loss of service life. The previous studies on the self-healing were primarily conducted with a single bacterial species or additional cementitious materials, and the synergistic effect of multi-bacterial consortia and rice husk ash (RHA) has not been well investigated. This research suggests a sustainable approach to improve the mechanical properties, durability and self-healing ability of cracks through the synthesis of a multi-bacterial self-healing concrete using the Microbially Induced Calcium Carbonate Precipitation (MICP) technique through incorporation of rice husk ash (RHA). Three binary bacterial consortia and bacterial dosages (10, 50 and 100 mL/L) were investigated in 28 concrete mixes along with 10, 20 and 30% RHA using compressive strength, flexural strength, ultrasonic pulse velocity (UPV), water penetration, crack-healing efficiency, SEM analyses. The optimum BC-100-RHA20 mixture had a 28-day compressive strength of 32.9 MPa, flexural strength of 5.31 MPa, UPV of 4.78 km/s, minimum water penetration of 11.9 mm and crack-healing efficiency of 96%, which was significantly higher than the control concrete. SEM showed high degree of calcium carbonate precipitation and fine pore structures. The results show that the addition of binary bacterial consortium to RHA is an effective and sustainable method for building concrete with long life infrastructure applications and low maintenance.