Self-healing of cementitious composites to reduce high CO₂ emissions

Existing concrete structures worldwide are suffering from deterioration/distress. With ever-growing urban population and global warming, higher CO₂ concentrations in the atmosphere are likely to further weaken the chemical stability of concrete material, and it is very important to understand how its effects will impair the material. To help moderate the harmful effects of increased CO₂ concentrations, an experimental study was undertaken in which efforts were made to accelerate the capability of engineered cementitious composites (ECCs) with different pozzolanic materials (PMs) to self-heal its own damage (for example, cracks) in a CO₂-rich environment. Self-healing was assessed by electrical impedance (EI) and rapid chloride permeability tests (RCPTs) on 28-day-old specimens. Experimental findings show that self-healing in a CO₂-rich environment is more pronounced than it is in normal atmospheric conditions. The findings also show that PM type can be very decisive on self-healing performance in a CO₂-rich environment, depending on testing method. Results suggest that proper material design can lead to the development of environmentally friendly ECC options with superior mechanical and durability characteristics.