Preparation Of Aerogel Thermal Insulation Material For Building Exterior Wall

In building energy consumption,the energy loss of external walls is higher,and its energy loss accounts for about 20%-30%of the total energy loss,which is the focus of building energy conservation.In recent years,SiO₂ aerogel as a new type of nano lightweight,multi-functional,environmentally friendly material,with its unique properties（low density,high specific surface area,low thermal conductivity and high light transmittance,etc.）has attracted more and more attention,especially as an efficient thermal insulation material has become a research hotspot.Therefore,it is of great significance to carry out the application of SiO₂aerogel in building energy conservation.In order to improve the thermal performance of building exterior walls and solve the problem of difficult treatment of thermal insulation solid waste,SiO₂aerogel thermal insulation mortar was prepared,and the influence of SiO₂ aerogel content on the performance of composite mortar was analyzed.Aiming at the excellent thermal insulation performance of SiO₂aerogel,SiO₂aerogel thermal insulation coating was prepared and its properties were studied.The heat transfer simulation of the composite structure exterior wall composed of SiO₂ aerogel insulation mortar and SiO₂aerogel insulation coating was carried out by finite element software ANSYS Workbench to predict the insulation effect.The results are as follows:SiO₂aerogel can reduce the dry density of composite thermal insulation mortar,mass water absorption,flexural strength,compressive strength,flexural compression ratio,thermal conductivity,improve the sound absorption effect of thermal insulation mortar.Fiber filler can increase the flexural-compression ratio of thermal insulation mortar and enhance the flexibility and crack resistance of composite thermal insulation mortar.When the cement 44wt%,aggregate 46wt%,SiO₂aerogel 10wt%,the dry density of thermal insulation mortar is 476 kg/m³,the thermal conductivity is 0.065W/（m·K）,and the compressive strength is 1.01 MPa.The new SiO₂ aerogel thermal insulation mortar meets the requirements of the current application of external wall thermal insulation mortar specifications.The SiO₂ aerogel insulation coating has a thermal conductivity of 0.043 W/（m·K）,no abnormality in water resistance test for 96h,no abnormality in alkali resistance test for 48h,no damage to the paint film after 2000 times of washing,a contrast ratio of 0.94,a smear rate of 8.7%,an aging time of 600h,no blistering,no peeling,no crack,a pulverization degree of grade 1,and a discoloration degree of grade 0.It can be applied to building exterior walls.SiO₂aerogel insulation mortar（30mm）and SiO₂ aerogel insulation coating（3mm）composite structure of the exterior wall,in the outdoor temperature of-10°C～40°C,the insulation effect is excellent,its energy-saving effect is suitable for China’s warm winter and cool summer areas.In cold regions,in order to achieve the same insulation effect,the thickness of the insulation layer can be increased on this basis.