An Investigation on Carbon Dioxide Incorporated Sustainable Ready-Mix Concrete Using OPC and PPC

Carbon dioxide, or CO 2 , is responsible for most global greenhouse gas emissions. Sequestering CO 2 in concrete can potentially reduce carbon emissions while simultaneously improving concrete's characteristics. This study's main objective is to use carbon dioxide in the Ready-Mix Concrete (RMC) during the mixing phase. This study also investigates the effects of carbon dioxide incorporation on the properties of concrete at different dosages (0% to 0.20% by weight of the binder) and binder types such as Ordinary Portland Cement (OPC) and Portland Pozzolana Cement (PPC). Through a detailed experimental study, the paper seeks to understand the changes in the various mixes' fresh, hardened, and microstructural properties. The results indicate that carbon dioxide had no adverse effect on fresh concrete properties, with minor changes leading to improved performance in concrete samples at precise dosages. The microstructural results reveal that the concrete tends to densify by utilizing the optimum dosage of carbon dioxide and thus achieve the best performance. Concrete mixtures treated with CO 2 showed increased compressive strength; 0.10% CO 2 in OPC-based mixes gave up to 30% benefit, and 0.05% in PPC-based mixes gave up to 25%. PPC-based had the highest compressive strengths at later ages, OPC-based at early ages. The time of set was reduced by 18% in OPC mixes and 28% in PPC mixes. Furthermore, the addition of CO 2 during mixing had a positive impact on the concrete's durability. Therefore, it can be concluded that utilizing CO 2 in concrete can help produce sustainable RMC with enhanced properties and reduced emissions.