Investigation on the properties of magnesium oxychloride cement prepared with seawater

摘要

Seawater from South China Sea was used instead of freshwater to fabricate magnesium oxychloride cement (MOC). To study the basic performance of the seawater-mixed MOC paste, the setting time, hydration exothermic characteristics, compressive strength, thermal stability, seawater resistance, phase composition and microstructure of the paste were analysed in detail. The results showed that the use of seawater in the MOC paste slightly retarded the setting time and increased the total hydration heat. The compressive strength and thermal stability of the seawater-mixed MOC were slightly lower than those of the MOC paste prepared with freshwater. The main hydration product of both MOC pastes was 5Mg(OH)(2)center dot MgCl2 center dot 8H(2)O. The residual strength ratio of the seawater MOC paste was 9.70% higher than that of the freshwater MOC paste after 28 d immersion in seawater. However, the standard deviations suggest that the properties of MOC pastes prepared with seawater or freshwater were not significantly different.