The Study On Insulation Materials Of Solid Waste Base Ultra-low Density Foamed Concrete

With the improvement of urbanization level in China,the energy consumption of buildings has become a huge burden for China’s economic development,and the use of thermal insulation materials is an important measure to reduce the energy consumption of buildings.At present,the commonly used organic thermal insulation materials are forbidden to use because of their weak resistance to fire,and the safety hidden danger.The inorganic thermal insulation materials will be the development direction of the thermal insulation materials.Density of super light foamed concrete(<300 kg/m3)due to its high porosity,make its have relatively low coefficient of thermal conductivity,and has good fireproof performance,make it have broad application prospects in the field of thermal insulation material.But the current frequently during the preparation of super light foamed concrete with large amount of high grade cement as raw material,match again with a certain amount of admixture to achieve lower density strength standard at the same time,this lead to product cost rise,directly influences its popularization and application.Therefore,it is necessary to research low cost and high performance ultrafine foamed concrete.In this study,vacuum foaming and polystyrene insulation boards were used to prepare ultrafine foamed concrete.The main research contents were as follows:(1)vacuum foaming method is used to prepare ultra-light foamed concrete.Firstly,water cement ratio,aluminum powder addition,calcium chloride addition and temperature were optimized under normal pressure condition,and then vacuum foaming experiment was carried out on this basis.Through the study of the on-line monitoring of vacuum foaming process,found that through in the process of slurry foaming vacuum can further reduce the density of foam concrete block,but for the slurry viscosity have higher requirements.With the increase of thickening agent,the foaming multiple of the slurry in vacuum condition is stable and then decreases.With the increase of vacuum degree,the foaming multiple of the slurry increased first and then decreased.At the same time,the density and strength of the test block showed similar trend of change,which decreased first and then increased.The change of water absorption rate is the opposite of density and intensity.Through the analysis of the change of the pore structure of foamed concrete under different vacuum degrees,it is found that the change of the test block performance is closely related to the pore structure change.Under this experimental system,the best thickening agent content is 0.2%,the lowest density of the vacuum degree is 0.02 MPa,density of 226 kg/m,relative to the atmospheric pressure foaming density was reduced by 31%,the compressive strength of block is 0.32 MPa.(2)preparation of polystyrene insulation composite foamed concrete insulation materials.The composite foamed concrete insulation material was prepared by pre-adding the polystyrene insulation board to the mold.In addition,the surface of foam board is pre-staggered and perforated to produce a chimeric effect between the foamed concrete and the insulation board,and the combination is more compact.When adding a thermal insulation board,the density of the composite material was 251kg/m3,and the compressive strength was 0.53MPa,which was 16.89%lower than that of the non-foam board,and the compressive strength was basically unchanged.When adding two insulation boards,the density of the composite material was 209kg/m3,the compressive strength was 0.86MPa,and the density decreased by 30.79%compared with the non-foam board,and the compressive strength increased by 51.05%.The compressive strength in the parallel direction of the composite material after adding the insulation board is higher than that in the vertical direction.After adding insulation board,the thermal conductivity of composite material decreased by 27.94%compared with that of pure foamed concrete.