The investigation of early hydration and pore structure of Portland cements containing waste dolomite powder based on 1H NMR

Abstract

Waste dolomite powder (WDP) is being actively investigated as the additive of Portland cement (PC) for lowering the energy consumption and carbon emission of PC. In this work, 1H low-field nuclear magnetic resonance (1H NMR) was used to analyze the impacts of WDP on the hydration and pore structure of PC pastes at the early age. Meanwhile, the compressive strengths of blended cements containing 5–20% WDP were also measured. The results show that the T2 average value and evaporable water content of all the pastes decrease dramatically from 0 to 24 h, and the reduction rate slows down after 24 h. Adding 5% WDP can decrease further the T2 average value and evaporable water content attributed to its nucleating and filler effect, resulting in the compacted pore structure and the higher strength. However, adding more than 5% WDP degrades the pore structure and lowers the compressive strength.