Study on the effect of carbonation treatment on concrete wash water

Abstract Wash water is a by-product of ready-mixed concrete production and currently lacks scientific recycling measures due to its high alkalinity and suspended solids content. To address this issue, this project investigated a novel approach utilizing a self-designed carbonation device. This device effectively carbonates the wash water, enabling its subsequent integration into cement mortar to assess its impact. A comprehensive analysis of the wash water was carried out using a variety of techniques. The findings from XRD, SEM-EDS, and ICP tests revealed that the carbonation triggers reactions in the hydration products of the wash water, leading to the formation of calcium carbonate, and TG analysis revealed a carbon sequestration rate of 16.11%. Notably, particle size analysis demonstrated that the calcium carbonate particles produced were nanosized, which could fill the tiny voids in the cement mortar, thereby enhancing its compressive strength. The strength test of the cement mortar showed that the compressive strength of the cement mortar mixed with carbonated wash water was improved, which increased by 13% compared with the control group.