Enhancement of the performance of concrete and flexural behaviour of beam using two-step CO2-mineralization

The reaction of the hydrating phase of cementitious materials with CO 2 produced micro-scale calcium carbonate, densifying concrete. Hence, this gives rise to double-fold benefits, improving concrete performance and permanently sequestrating CO 2 . The primary method for adding CO 2 to concrete is accelerated carbonation curing; the limited diffusion rate, the requirement for a large airtight chamber, and use exclusively in pre-cast concrete are some of the limitations of carbonation curing. Aiming to overcome these limitations of using CO 2 in concrete only through accelerated carbonation, a novel two-step CO 2 mineralization method was used in the present work. In the present work, CO 2 was first sequestrated into calcium-rich cementitious materials such as cement, and then it was mixed with the rest of the concrete ingredients to produce CO 2 -mineralized concrete. Findings of the present work reveal that a dose of 0.2 % of CO 2 by the weight of cement gives rise to optimum compressive strength, 19.78 % higher than conventional concrete at 28 days of testing. The benefit of strength gain can be used to leverage the cement content, and this practice of CO 2 mineralization leads to lowering the consumption of cement by 7.5 % without compromising concrete performance, and a total of 8 % carbon emissions reduction can be achieved. Using CO 2 in concrete improves the first crack load and the ultimate load capacity by 14.80 % and 14.72, respectively. Additionally, the tested CO 2 mineralized concrete with lowered cement content has equivalent durability performance marginally higher than conventional concrete.