Effects of modifiers on properties of magnesium oxysulfide cement prepared with additives of mineral and solid waste
Magnesium oxysulfide(MOS)cement is a gas-hardening cementitious material composed of MgO-MgSO4-H2O ternary system,which is used in the fields of fireproof door core panels and exterior wall insulation panels.However,traditional MOS cement is limited in wider application due to the lack of modification treatment.In this paper,MgO powder and magnesium sulfate are used as the main raw materials to prepare MOS cement with mineral kaolin and solid waste fly ash as active admixtures.The effects of modifiers,such as citric acid,malonic acid and trisodium phosphate,on the phase compositions,mechanical properties,and microstructures of MOS cement are investigated.The results show that when using 0.5%citric acid and 0.2%malonic acid,the 5Mg(OH)2·MgSO4·7H2O phase characteristics of MOS cement become significant.The sample structure is compact,and its 28-day mechanical properties have the best performance,with compressive strength and flexural strength reaching 100.14MPa and 28.61MPa respectively.
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