Influence of Multiple Factors on Compressive Strength of Magnesium Oxychloride Cement Concrete

The compressive strength of magnesium oxychloride cement concrete in western regions of China was studied. The adaptability of the Taguchi method in mix proportion design of concrete was also studied. The effects on the compressive strength of magnesium oxychloride cement concrete were studied utilizing the following variables: molar ratio of active MgO to MgCl₂, fly ash, water resistance modifier, and the percent of water reducer. Through quantifiable characterization, the impact of these variables on the compressive strength of magnesium oxychloride cement concrete was determined. A multivariate nonlinear regression model was proposed to determine the signal-to-noise ratio of magnesium oxychloride cement concrete. When designing for the 28 day compressive strength, it was concluded that the optimum magnesium oxychloride cement concrete composition is as follows: molar ratio is 5.4, no fly ash, 1% phosphoric acid as a water resistance modifier, and 1% water reducing agent. The impact of the variables from largest to smallest is as follows: water reducer, fly ash, molar ratio, and percent of water resistance modifier. However, when designing for the long-term compressive strength, the optimal composition of magnesium oxychloride cement concrete is as follows: molar ratio is 5.4, no fly ash, 2% phosphate fertilizer as the water resistance modifier, and 1% water reducing agent. The impact of these variables also changes, and the effects in order from largest to smallest are: molar ratio, fly ash, water-resistant modifier, and water-reducing agent percentage.