DEVELOPMENT OF CO₂ INHALING BIO-HEALABLE CONCRETE WITH ENHANCED IMMUNITY TO CORROSION

Abstract

Urbanization trend in Pakistan over the decades has increased abruptly which calls for increased construction to meet the demands of ever-growing population. Construction sector is one of the major contributors of CO2 emissions that has led to world facing global warming issues. Since concrete is a popular construction material primarily because of its strength, it has the tendency to develop micro structural cracks that gradually deteriorates its properties owing to embedded reinforcement exposed to chloride ions that leads to corrosion. Self-healing is potential remedy to this problem. Various researches have been conducted to investigate self-healing and bio-influenced self-healing has been concluded to be the best approach in terms of crack healing and strength recovery. Bio-influenced self-healing can be achieved by immobilizing bacteria in nano/micro fillers such as carbonized char, but most of these fillers are incompatible with alkaline concrete environment rendering the effectiveness of long-term healing. In this research study, nano/micro carbonized char was used to examine healing activity at various ages, investigate the corrosion potential and quantifying CO2 sequestration ability of self-healing concrete. Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), Thermogravimetric Analysis (TGA) and Optical Microscopy were conducted to verify self-healing. Corrosion was examined through Tafel Polarization, Weight Loss Measurement, Sorptivity test and Non-Steady State Chloride Ion Migration Coefficient Experiment. CO2 sequestration ability was quantified by developing a climate monitoring chamber. Experimental results reveal that carbonized char is an effective carrier to immobilize bacteria with maximum healing reported to be 4 mm having a strength recovery of 96.3%. corrosion reduction potential was found to be 82% and CO2 sequestration ability of self-healing concrete was 3 times compared with a normal concrete.