Promoting effect and mechanism of several inorganic salts on hydration reaction of magnesium oxychloride cement at low temperature

In this work, the Magnesium oxychloride cement (MOC) added with five kinds of inorganic salts (CaCl 2 , Ca(NO 3 ) 2 , KCl, LiCl, and NH 4 NO 3 ) were prepared under the low temperature (5 ℃), and the effects of inorganic salts on the hydration reaction and engineering properties were investigated. The results show that the addition of inorganic salt can significantly improve the hydration reaction rate, increase the content of the 5-phase, and shorten the curing time. Compared with pure MOC, the compressive strength of MOC added with CaCl 2 increased by about 128% after 7 days of curing. Moreover, the existence of inorganic salts weakened the surface shielding layer [Mg(H 2 O) 6 ] 2+ of active MgO, thereby improving the zeta potential of active MgO and promoting the diffusion rate of Mg 2+ . Overall, these results could provide valuable information for studying the hydration reaction and engineering performance of MOC at low temperatures.