Modification Of Foamed Concrete

Foam concrete is a new inorganic insulation materials,light weight,good insulation properties,excellent sound insulation fire resistance,good seismic performance,strong waterproof performance,has been used in many aspects of construction projects for building energy efficiency demand,has great room for development,but because of the lightweight foam concrete is bound to have insufficient strength.And the development of waste,such as the application of fly ash,silica fume,slag,phosphorus slag powder,rubber powder in the foam concrete have significant resource recycling and environmental significance.In this paper,hydrogen peroxide as a foaming agent,used mineral admixtures replace part cement to prepare the density 400kg/m3～700kg/m3 foam concrete,use additives and basalt fiber modified foam concrete.Study the mineral admixtures,additives,rubber powder and fiber influence on the mechanical properties of the foam concrete physics.And on this basis,use orthogonal experiment to design experiment to study the effect of ash,rubber powder,basalt fiber,calcium stearate on foam concrete block compressive strength,water absorption and thermal coefficient of volume,derived foam optimum concrete mix.Test results show that compared fly ash,silica fume,slag,phosphorus slag powder these four mineral admixtures,used fly ash to prepare foam concrete,the performance of foam concrete is relatively good,and the best content is 30%.The influence of admixtures on foam concrete,the calcium stearate content should be>0.8%and 1%for the best content.Adding the right amount of polyacrylamide and hydroxypropyl methyl cellulose in foam concrete can have a good foam stabilizing effect,the best amount isl.5%.For foam concrete water-cement ratio is also appropriate range,too large or too small will cause a decline in compressive strength.Taken together,the appropriate water-cement ratio is 0.55.With the increase of rubber powder content,the foam concrete dry density fell,40 mesh rubber powder with minimal impact on the dry density foam concrete,120 mesh greatest impact.Foam concrete mixing rubber powder produced lower compressive strength and the same dosage,the smaller the particle size,the greater the compressive strength decreased.With the increase of rubber powder content,the thermal conductivity of the foam concrete is reduced,it means the block insulation performance improvement.The smaller the particle size of the rubber powder is,the larger the heat transfer coefficient is reduced.Mixing rubber powder can improve the water-absorbing of foam concrete.With the increase of basalt fiber content,density and water absorption almost no change,compressive strength and flexural strength are first increased,then decreased.With the increase of basalt fiber length,foam concrete compressive strength and flexural strength are first increased and then decreased.The influence of basalt fiber length on foam concrete thermal conductivity is not affected.Designed four factors and three levels orthogonal experiment,comprehensive water absorption,compressive strength,thermal conductivity three performance assessment indicators,and ultimately determine the amount of mineral admixture fly ash of 30%;calcium stearate in an amount of 1%;40 mesh rubber powder in an amount of 7.5%;basalt fiber in an amount of 1.2kg/m3.This experiment will provide a reference for the research on the modification of foamed concrete.