Study On Fire Resistance Performance And Microstructural Regulation Of Foam Concrete

As an excellent lightweight material,the application of foam concrete in buildings can not only reduce building energy consumption,but also reduce the great damage caused by fire caused by building insulation materials to human life and property.Under the condition of fire,the non combustibility and smokeless properties of foam concrete make it occupy a great advantage in building insulation materials.Therefore,it is particularly important to study the microstructure,thermal conductivity,mechanical properties and fire resistance of foam concrete in order to enhance the fire performance of foam concrete.In this paper,two kinds of cementitious materials,composite Portland cement and magnesium oxysulfate cement,were used to make foam concrete respectively.By means of single variable method,water-cement ratio to 0.45-0.65,hydrogen peroxide content in4%-7.5%,xanthan gum content in 0.01%-0.05% and polycarboxylic water reducer content in0.02%-0.05% was changed.The basic ratio changed to the foam concrete with two different cementing materials.The influence of structure,thermal conductivity,mechanical properties and fire resistance,and the relationship between the thermal conductivity of foam concrete and the average pore size and porosity are discussed.The results show that with the increase of water-cement ratio and hydrogen peroxide content,the average pore size,porosity and pore size distribution of foam concrete increase,and the thermal conductivity decreases.With the increase of xanthan gum content and polycarboxylic water reducer,the average pore size,porosity and pore size distribution of foam concrete decrease,and thermal conductivity increases.The average pore size,porosity and pore size distribution of acid foam concrete are smaller than those of magnesium oxysulfate foam concrete,and the thermal conductivity of composite silicate foam concrete is larger than that of magnesium oxysulfate foam concrete.Under the condition that the average pore size and porosity were not controlled,the thermal conductivity of composite silicate foam concrete and magnesium oxysulfate foam concrete decreased with the increase of average pore size and porosity of foam concrete.With the increase of water-cement ratio and hydrogen peroxide content,the compressive strength loss rate of composite silicate foam concrete and magnesium oxysulfate foam concrete gradually increased when the calcination temperature was 800 degrees high.With the increase of xanthan gum content and polycarboxylic water reducer content,the compressive strength loss rate of composite silicate foam concrete and magnesium oxysulfate foam concrete decreased first and then increased.Under fire condition,with the increase of water-cement ratio and hydrogen peroxide content,the fire resistance time of composite silicate foam concrete and magnesium oxysulfate foam concrete decreases.With the increase of xanthan gum content and polycarboxylic water reducer,the fire resistance time of composite silicate foam concrete and magnesium oxysulfate foam concrete increases.By studying the microstructure,thermal conductivity,mechanical properties and fire resistance of composite silicate foam concrete and magnesium oxysulfate foam concrete,this study has great guiding significance for the study of foam concrete and the application of foam concrete in building thermal insulation and fireproofing materials.