Preparation And Performance Investigation Of Basic Magnesium Sulfate Cement Foamed Concrete

In this paper,lightweight and high-strength basic magnesium sulfate cement was used as a base material to prepare foamed concrete insulation materials by adding modifier,foaming agent,expanded perlite,foamed stabilizer,water reducing agent and mineral admixture.The influence rule of each component on the basic magnesium sulfate cement foam concrete was studied,and the material ratio was optimized by orthogonal test and variance analysis,so that the material properties could meet the requirements of low thermal conductivity,low density,high strength and low water absorption.By means of X-ray diffraction?XRD?and scanning electron microscopy?SEM?,the hydration products and microstructure of samples and their correlation with macroscopic properties were analyzed.By researching the effect of each component on the performance of basic magnesium sulfate cement foamed concrete,the following laws are obtained.Compared with hydrogen peroxide solution,hydrogen peroxide powder lags behind in the process of forming bubbles,which can reduce the generation of through holes.With the increase of foaming agent content,the dry density,flexural strength and compressive strength of samples decreased.With the increase of the content of modifier and expanded perlite,the dry density,flexural strength and compressive strength of the samples increased.When the content of water reducer is between 1%and 3%,the dry density,flexural strength and compressive strength of the specimens increase with the increase of water reducer content,and the pore structure is uniform and dense.When the content of foamed stabilizer is between 1%and 3%,the dry density,flexural strength and compressive strength of the samples decrease with the increase of the content of foamed stabilizer.With the increase of slag content,the dry density of the sample increases and the compressive strength decreases,but the flexural strength increases.It has good acid corrosion resistance and can be used in projects requiring high acid corrosion resistance.The dry density,flexural strength,compressive strength,water absorption and thermal conductivity of the material were obtained by orthogonal test,and the variance analysis method was used to determine the two optimal mix ratios.The optimum mix ratio of comprehensive equilibrium method is 9:1:20 for MgO:MgSO₄:H₂O,1%for modifier,15%for expanded perlite,7.5%for foaming agent,0.5%for water reducer and 2%for foamed stabilizer.The basic magnesium sulfate cement foamed concrete slab with dry density of 312.5kg/m³,flexural strength of 0.34MPa,compressive strength of 1.12MPa,water absorption of 46%and thermal conductivity of 0.117W/?m·??were prepared.Compared with the standard,the dry density decreased by 30.56%.The optimal mix ratio of optimal order method is 8:1:20 for MgO:MgSO₄:H₂O,1%for modifier,15%for expanded perlite,4.5%for foaming agent,0.5%for water reducer and 3%for foamed stabilizer.Thebasic magnesium sulfate cement foamed concrete slab with dry density of 472.3kg/m³,flexural strength of 0.95MPa,compressive strength of 3.05MPa,water absorption of22%and thermal conductivity of 0.166W/?m·??were prepared.Compared with the standard,the dry density decreased by 27.34%.By analyzing the hydration products and microstructure of the magnesium sulfate cement foam concrete,it is found that the hydration products of foam concrete mixed with cement modifier,foaming agent,expanded perlite,foam stabilizer,water reducing agent and mineral admixture have not changed.The change of the strength of the sample is mainly caused by the change of the internal pore structure.When the pore size is less than 1mm,the properties of the sample are better.