Experimental study on magnesium oxychloride cement concrete

Magnesium oxychloride cement concrete specimens can be produced in different ratios by experimental design and analysis using the Taguchi method. The significance sequences of strength and water resistance of the selected controllable factors were studied under dry and flooding conditions respectively, and the sensitivity sequence and the most robust set level of the factors were analyzed. The results show the following: the significance sequences are consistent under different conditions. The selected controllable factors were phosphate, fly ash, molar ratio of activated magnesium oxide (MgO) to magnesium chloride (MgCl₂) of 5·4 and phosphoric acid. The maximum sensitivity factor under both conditions is phosphate; the most robust levels are consistent for a molar ratio of activated magnesium oxide to magnesium chloride of 5·4, without ash and without phosphoric acid. However, the results for phosphate are inconsistent. The amount of phosphate, added at the most robust level under dry conditions, is more than the amount under flooding conditions, so that the most robust set level of the factor under dry conditions will reduce its water resistance.