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.

Keywords:

• Waste dolomite powder
• ¹H NMR
• hydration
• pore structure

Conflict of interest statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The authors would like to acknowledge the National Natural Science Foundation of China (52208279), Natural Science Foundation of Jiangsu Province of China (BK20220639), and Natural Science Foundation of the Jiangsu Higher Education Institution of China (20KJB560007).