Preparation and characterization of one-part magnesium oxychloride cement

This work aims at enhancing the commercial viability of magnesium oxychloride cement (MOC) by preparing one-part MOC (just added water). It was synthesized by mixing of magnesium chloride (MgCl2) with magnesium oxide (MgO) at water to MgO (W/MgO) ratios, making MOC-paste in non-workable form. The MOC-slurry was immediately dried in an oven at 60 °C for 24 h, yielding solidified material which pulverized to produce one-part-MOC powder with a fixed particle size. Two major factors, which affect the performance of one-part MOC, were examined: the first is the increase of MgO/MgCl2 molar ratio, while the W/MgO ratio is kept maintaining constant. The second includes the increase of W/MgO ratio at constant MgO/MgCl2 molar ratio. One-part-MOC powder was mixed with water at W/MOC powder ratio of 0.25, and then cured. A traditional two-part MOC containing MgO (solid part) and MgCl2 solution (liquid part) was used for comparison. The results revealed that the W/MgO ratio and MgO/MgCl2 molar ratio strongly affect the performance of one-part MOC. The compressive strength development of the hardened cement pastes proved the continuation of hydrate phases formation after mixing one-part-MOC with water. At 14-day of curing, the compressive strength value of an optimal one-part MOC was found to be lower than that of two-part-MOC, containing the same MgO/MgCl2 molar ratio, by 14%.