Water evolution and hydration kinetics of cement paste under steam-curing condition based on low-field NMR method

Abstract The presented study focuses on the water evolution and hydration characteristics of Portland cement paste under steam-curing condition. The detailed information concerning water consumption and micro-pore network as well as the corresponding hydration kinetics of hydrating cement paste (HCP) during steam-curing process were discussed based on the low-field nuclear magnetic resonance measurement. The results indicate that, within steam-curing period, most of the free water in HCP are distributed in smaller pores less than 500 nm. The water evolution rate of paste system can be divided into three stages, i.e. acceleration stage within heating period and the first 2 h of constant-temperature period, rapid low-down stages in later constant-temperature period and diffusion stage in rest period. The curing temperature predominantly controls the water evolution rate. Finally, the hydration kinetics model of paste within steam-curing period is established and verified by experiment.