Research On The Properties Of Mgnesium Oysulfate Cment Modified By Cfbc Fly Ash And Its Application

Traditional magnesium oxysulfate cement was made of light-burned magnesia and magnesium sulfate solution,which is poor physical and mechanical properties, poor water resistance, poor volume stability, easy crystallization. Fly ash can improve the physical and mechanical properties and water resistance of magnesium oxysulfate cement, there are many similar characteristics between fly ash and CFBC fly ash,but now CFBC fly ash has large annual discharge. Therefore, this study aimed to study the influence of CFBC fly ash on the magnesium oxysulfate cement properties,It is expected that the production of lightweight partition wall panels is prepared with magnesium oxysulfate cement modified by CFBC fly ash.The ranges of Mg O/Mg SO4 molar ratio, H2O/Mg SO4 molar ratio, and the citric acid content were determined by single factor experiments. Mg O/Mg SO4 molar ratio, H2O/Mg SO4 molar ratio, and the citric acid content were determined by orthogonal experiment,therefore,the fiducial mix pro portion of magnesium oxysulfate cement could be determined.For improving properties of magnesium oxysulfate cement further, some industrial by-products were mixed in this system, The study shows CFBC fly ash can well improve the performances of magnesium oxysulfate cement.In order to achive hight performances magnesium oxysulfate cement with CFBC fly ash, we study the influences of finensee,content and chemical composition of CFBC fly ash on the properties of magnesium oxysulfate cement,therefore,the optimal mix proportion of magnesium oxysulfate cement was determined, Exploration Production process parameters of lightweight partition board made of magnesium oxysulfate cement foamed concrete.The results show that :citric acid can significantly improve the ph ysical and mechanical properties of magnesium oxysulfate cement, the optimal mix proportion : Mg O/Mg SO4 molar ratio is 20, Mg O/Mg SO4 molar ratio is 12 and the citric acid content is 1.5%. Magnesium oxysulfate cement with citric acid provides very good performances. CFBC fly ash can reduce the heat of cement hydration in the early stage, reduce the shrinkage rate of magnesium oxysulfate cement, reduce the porosity of cement stone,improve the density of cement stone, improve the physical and mechanical prope rties of cement stone.When the CFBC fly ash content is 20% of light-burned magnesia,the comprehensive strength at 28 days achieved 78.7MPa, improve 12.3MPa, improve the rate of 18.45%. When the CFBC fly ash was grinded into a median diameter of 15.88 μm, the CFBC fly ash content of 8%, the comprehensive strength at 28 days achieved 80.7MPa, improve 14.3MPa compared with the blank control grou p, improve the rate of 21.55%.At lower contents of active Si O2,f-Ca O,SO3 in CFBC fly ash, increasing the content will extend the setting time, improve the comprehensive strength, with the increasing of the content of active Si O 2,f-Ca O,SO3 in CFBC fly ash,it will have the opposite effect. The optimally technical parameters of lightweight partition board made of magnesium oxysulfate cement foamed concrete are that the dilution ratio of foaming agent was 1:20, foam formation rate was 20, drying environment maintenance at 20℃,the content of foaming agent was 1.11% of the light-burned magnesia quality.The samples satisfy the requirement of standard of GB/T 23451-2009,and the comprehensive strength and water resistance of samples are better。...