Thermodynamics-based simulations of the hydration of low-heat Portland cement and the compensatory effect of magnesium oxide admixtures
Wenwei Li, Yifan Zhou, Jiajie Yin, Yuxiang Peng, Yushan Wang, Shengwen Tang, Yan Shi, Yang Wang, Lei Wang
Abstract
Low-heat Portland (LHP) cement is a new type of Portland cement that has been widely used in recent years due to its low heat of hydration, which makes it exceptional in temperature control for mass concrete construction. However, limited studies have investigated the impact of temperature and magnesium oxide (MgO) content on LHP cement-based materials. This study utilizes thermodynamic simulations to study the hydration process, pore structure, and autogenous shrinkage of LHP cement pastes with different water-to-cement ratios (0.3, 0.4, and 0.5), curing temperatures (5, 15, 20, and 30 °C), and MgO contents (mass fractions of 2%, 4%, and 5%). Higher curing temperature is found to promote the hydration reactions in cement paste. Moreover, the incorporation of 4% MgO moderately decreases both porosity and dimensional shrinkage in pastes. The microstructural evolution of different LHP pastes is examined through a comparative analysis, lending insights into LHP cement-based material applications.