Development Of Basic Magnesium Sulfate Cement Decorative Mortar

In this fast-developing country,the construction industry is rapidly developing,and the use of building mortar is also increasing.For the wall decoration materials,decorative mortar have characters of breathable,good hydrophobic,environmental friendly,long life and high safety,and with good prospects for development.In this paper,basic magnesium sulfate cement as the cementitious material,selecting the different molar ratio,mortar ratio,quartz sand particle size ratio for the initial exploration test.Through the test mortar at different ages consistency,water retention,flexural strength,compressive strength,bending bond strength,etc,and the initial choice of test mortar mix required.Then,the different grade of quartz sand particles were optimized by orthogonal test to determine the gradation of quartz sand particles for follow-up test.With reference to the literature on decorative mortar,selecting the admixture to improve the performance of the decorative mortar and determine the extent of admixture incorporation.Firstly,the optimization was choose from the single variable through the control variate method.Then the three factors three levels orthogonal experiment was established by the incorporation of redispersibility emulsion power,cellulose ether and slag,and the optimal ratio was optimizeel.Finally,the mechanism of the components of the basic magnesium sulfate cement influence the performance of decorative mortar was further studied through the microstructure analysis of XRD and SEM.Under the same curing conditions,the mix propotion of decorative mortar was optimized by the control variable method and the orthogonal test.The molar ratio of MgO:MgSO₄:H₂O was 5:1:20,the sand-blinder ratio of the mass of MgO and sand was 1:2,quartz sand particle size ratio?the quartz sand mass ratio of 20 to 40 mesh,40 to 80 mesh and 80 to 120 mesh?was 3:1:3,citric acid content is 1%of the mass of MgO,the content of the redispersibility emulsion power is 2%of the mass of MgO,the content of cellulose ether is 0.5%of the mass of MgO and the content of slag is15%of the mass of MgO.Through the optimization of each component?Consistency:105±10mm.Appearance:uniform,non-sticky,no impurities.30 min operational time:blade coating easily.Initial dry cracking resistance:no cracks.Water retention above 95%,28 d flexural strength?2.50 MPa,28d compressive strength?4.50 MPa,28d bending bond strength?0.50MPa?,the qualified and decorative basic magnesium sulfate cement decorative mortar was obtained.