Research On Key Influence Factors And Preparation Of High Performance Foam Concrete

Foam concrete is a new type of energy-saving insulation material with the characteristics of lightweight,heat preservation,heat insulation,shock absorption and wave absorption.It has been widely used in thermal insulation materials,wall materials,Processing,mining area filling and so on.Compared with the traditional organic insulation materials,foam concrete burning level is A,which can avoid the impact of fire.However,the foam concrete still has the problems of high thermal conductivity,low compressive strength,large shrinkage and poor integrity.In order to improve the above-mentioned problems of foamed concrete,this paper explores the influence of foamed concrete from both gas phase and solid phase,and draws the following conclusions:(1)Foaming gas affects the thermal conductivity of foamed concrete.With the same dry density of foamed concrete prepared from the same cementitious material,the smaller the thermal conductivity of the foaming gas,the smaller the thermal conductivity of the foamed concrete.(2)Gas-phase gas in foamed concrete can affect the compressive strength of foamed concrete.The carbon dioxide gas can react with the hydration products of the sulphoaluminate cement to form calcium carbonate and hemihydrate gypsum.It plays a role of internal curing inside the foamed concrete and improves the compressive strength of the sulphoaluminate cement foam concrete.(3)The cementitious material can affect the compressive strength of foamed concrete.The higher the strength of the cementitious material base material,the higher the compressive strength of the prepared foamed concrete.High-strength foamed concrete was prepared using magnesium phosphate cement as the cementing material and hydrogen peroxide as the foaming agent.When the dry density was 300~1000 kg/m3,the compressive strength was 1.8~22 MPa.Compared to OPC and SAC foamed concrete with the same dry density,magnesium phosphate cement foamed concrete has high strength characteristic.(4)When the foaming gas is the same,the thermal conductivity of the cementitious material determines the thermal conductivity of the foamed concrete.The higher the thermal conductivity of the cementitious material,the higher the thermal conductivity of the foamed concrete.The same dry density of foamed concrete,the thermal conductivity of magnesium phosphate cement foamed concrete is significantly higher than ordinary portland cement and sulphoaluminate cement foamed concrete.(5)During the test,attempts were made to prepare OPC and SAC foamed concrete with carbon dioxide as the foaming gas.The results show that SAC foamed concrete can be prepared by chemical foaming using aluminum nitrate and sodium bicarbonate as foaming agents,and the compressive strength is higher than SAC foam concrete with other gases as foaming gas.