Effect of Exposure Conditions and Internal Curing on Pore Water Potential Development in Cement-Based Materials

Abstract

Moisture availability is a crucial factor for ongoing hydration reactions and controlling capillary pore water potential (PWP) development in cement-based mixtures. Harsh exposure conditions (such as low relative humidity, high temperature, or high wind speed) or incorporating fine cementitious materials may increase the mixture susceptibility to PWP development, and thus, early-age shrinkage. This study aims to investigate PWP and electrical conductivity development in cement paste and mortar mixtures with various water-to-cement ratios (from 0.25 to 0.4), silica fume substitutions, and internal curing in both sealed and harsh exposure conditions (ambient temperature from 10 to 35°C and relative humidity from 25% to 75%). The results indicate that high ambient temperature and silica fume incorporation substantially accelerate moisture loss and PWP development. The outcome of this study also shows the capability of internal curing using lightweight fine aggregate to delay PWP development in mixtures containing silica fume or exposure to low relative humidity and high-temperature ambient environments.