The effect of curing time and mix parameters on the sequestration of carbon dioxide in concrete
The purpose of this research is to investigate the potential for using recovered CO2 to develop a carbon-negative sustainable PCC. A preliminary study is presented to maximize the potential of PCC to absorb CO2 through optimized mix design and modified mixing/curing procedures. Accelerated carbonation through the use of a controlled CO2 chamber was used to enhance absorption. The effect of CO2 absorption is correlated with the PCC strength properties and the carbonation depth after 28-day. This study is different from previous work in that it is directed towards the influence of initial curing times as well as the introduction of using carbonated water in the mix design.
The experimental plan is to study the influence of water type, supplementary cementitious materials, local aggregate sources and curing combination between carbonated/non-carbonated medium to increase the capability of PCC mixes to absorb CO2. The PCC mixes were evaluated by the hardened properties and carbonation depth.
In this research, concrete with initial curing of 1- and 3-days, showed an overall higher compressive strength at 28-day. The batches mixed with 25% fly ash showed higher carbonation depths than the other mixes. Results implied that carbonation of concrete can overcome the effects of a shorter initial curing period. Also, fly ash has a greater effect on carbonation than mixes without mineral additives.