Study On Relative Properties And Preparation Of Basic Magnesium Sulfate Cement Based Lightweight Materials

Basic magnesium sulfate cement,as a new type of cementitious material with high light and high strength and low energy consumption,has an important development and application prospect in lightweight wall materials.Based on the research status of basic magnesium sulfate cement-based lightweight wall materials,this paper takes basic magnesium sulfate cement as the main cementitious material,and prepares basic magnesium sulfate based lightweight materials by foaming technology,lignin fiber modification,using vermiculite and pottery as light aggregates,and mixing with building gypsum powder,and studies its related properties,It provides theoretical and experimental basis for the development of basic magnesium sulfate cement-based lightweight materials and their application in wall materials.In this paper,the effects of foaming technology and lignin fiber modification on the properties of basic magnesium sulfate cement-based lightweight materials and their laws were studied.On this basis,the basic magnesium sulfate based lightweight materials with different density grades were prepared by using light aggregate such as ceramics and vermiculite and gypsum admixture,and their related properties were studied.The results can provide theoretical and experimental basis for the development and application of basic magnesium sulfate cement-based lightweight materials.The specific research contents and results of this paper include:(1)Preparation of basic magnesium sulfate cement foaming materials and related properties of the study.The effects of water cement ratio,cement dosage,foaming agent dosage and lignin fiber dosage on the mechanical properties,softening coefficient and water absorption rate of basic magnesium sulfate cement foaming materials were considered,and the changes of microscopic phase composition and microstructure were observed by scanning electron microscopy and XRD.Basic magnesium sulfate cement lightweight materials with a density range of480kg/m~3~880kg/m~3,a compressive strength range of 2.8MPa~7.8MPa,a low water absorption rate and a good softening coefficient were prepared.(2)Preparation of basic magnesium sulfate ceramic foam lightweight concrete test block.The effects of cement content,water cement ratio,lignin fiber dosage and ceramic dosage on the strength,softening coefficient and water absorption rate of ceramic foamed concrete test block and its regularity were studied.And the basic magnesium sulfate ceramic foamed concrete with apparent density in 700kg/m~3~800kg/m~3 and compressive strength in 3.5MPa~6.2MPa,with good water resistance and water absorption rate was prepared.(3)Preparation of basic magnesium sulfate ceramics-vermiculite lightweight concrete test block.According to the design ratio of dry apparent density method,the lightweight concrete test block of dry apparent density 900kg/m~3 was prepared by using basic magnesium sulfate cement,lightweight aggregate vermiculite and light ceramics.The effects of the pretreatment mode and reasonable dosage of vermiculite and the amount of ceramics,cement and lignin fiber on the strength of ceramic-vermiculite concrete test block were investigated.Based on this,a ceramic-vermiculite lightweight concrete test block with ideal homogenization and compressive strength and good softening coefficient was prepared.(4)Preparation of basic magnesium sulfate-building gypsum composite lightweight materials.Using building gypsum powder instead of a certain proportion of basic magnesium sulfate cement,the basic magnesium sulfate-building gypsum composite lightweight materials were prepared,and the effects of water cement ratio,building gypsum dosage,mechanical strength of water reducer on the mechanics of composites,slurry flow,setting time and softening coefficient were studied.The changes of microscopic crystal structure and phase composition were observed by scanning electron microscope and XRD.The effect of methyl silicate aqueous solution on the water resistance of composite test blocks was investigated.The apparent density was lower than1950kg/m~3,and the basic magnesium sulfate-building gypsum composite lightweight material with high early strength,good mechanical properties,ideal softening coefficient and suitable setting time was prepared.