Study on carbon sequestration and CO₂ mixing of fresh cement mortar

To ensure sufficient reaction between concrete and carbon dioxide, carbon dioxide was added during the concrete mixing process. The study involved varying water-to-cement ratios (W/C), carbon dioxide pressure, and carbon dioxide concentration to create different cement mortar samples. The research aimed to observe the effects of carbon dioxide sequestration under these parameters. Subsequently, mortar concrete properties were tested at different curing times. The findings indicated that this method enhanced the efficiency of cement mortar in absorbing carbon dioxide. The results revealed that mixing mortar with carbon dioxide led to a rapid reaction, reducing the initial setting time of cement mortar. However, it was observed that this method significantly decreased the workability of cement mortar after carbon dioxide mixing, and this effect could potentially be mitigated by adjusting the W/C or using a superplasticizer. The bond of cement was also found to decrease after reacting with carbon dioxide, consequently impairing the compressive strength of the concrete. Nevertheless, the compressive strength remained within acceptable limits. It is essential to note that the carbonation of the concrete and its ability to protect reinforcement from rusting were compromised due to the reduced pH value of the concrete. Further assessment of the durability is necessary, particularly if this method is applied to reinforced concrete structures.