Effect of carbonation on the moisture transport characteristics of cement blended with blast furnace slag

Understanding the water distribution and drying process in hardened cement pastes is essential because it directly influences several durability-related properties. It is widely established that the water distribution during drying behaves anomalously in both carbonated and non-carbonated cement pastes. To investigate the key differences in moisture transport, drying process, and water retention, specimens made with 40% and 60% ground granulated blast furnace slag, both carbonated and non-carbonated, were investigated. The results showed that carbonation-induced microstructural changes were minimal, with limited densification due to CaCO3 precipitation. This led to a greater mass increase in the cement pastes compared to those with ground granulated blast furnace slag. During drying, carbonated ground granulated blast furnace slag mixtures exhibited a higher initial drying rate than their non-carbonated counterparts. However, in the later stages, the drying behavior of all specimens converged. Overall, the drying curves of the carbonated samples can be accurately described using an exponential function that reflects the influence of microstructural modifications, complex internal structures, and heterogeneous porosity introduced through carbonation.