Influence of hygiene tissue paper used as an additive on the physicochemical and mechanical properties of CO2-cured belite-rich cement paste

The present study investigated the fresh, hardened, and physicochemical properties of CO2-cured belite-rich cement (BRC) paste incorporating hygiene tissue paper (HTP) as an additive. HTP was added at 0.5 and 1.0% by wt. of BRC paste. The BRC paste was prepared at a water-to-cement ratio of 0.4 and cured under water and carbonation. The results demonstrated that upon carbonation, the incorporation of HTP at 1.0% increases the CO2 uptake and compressive strength of specimens by 18.60% and 22.29%, respectively. A pore structure analysis shows a decrease in the threshold pore size diameter with an increase in the HTP content for CO2-cured samples. An SEM analysis revealed precipitation and impregnation of calcites in and around the HTP microfiber particles. The incorporation of HTP under water curing on the other hand did not significantly influence the strength or the physicochemical properties. It was observed that HTP contributes to improving the properties of CO2-cured BRC paste in two ways; the porous structure of HTP provides pathways for the deep permeation of CO2 into the matrix, and the surface of HTP offers an additional area for calcite precipitation.