Experimental Study On Silica Aerogel To Improve The Thermal Insulation Performance Of Foam Glass And Expanded Perlite

Combined with China’s current building energy consumption structure,the study of building exterior wall insulation materials is conducive to promoting China’s building energy conservation to reach a new height.The insulation performance of organic insulation materials is excellent while taking into account the light weight,but the service life is not long,easy to age,easy to burn and the combustion products are toxic.At a time when fire safety is getting more and more attention,inorganic insulation materials are getting more and more attention.Although inorganic insulation materials have a longer service life and are non-flammable,their thermal insulation performance is usually slightly inferior to organic insulation materials,and some inorganic insulation materials also have the disadvantage of strong water absorption,which limits the use of inorganic insulation materials in the field of building exterior wall insulation.SiO₂aerogel water is a nanoporous material with low thermal conductivity but poor mechanical strength.Therefore,considering the use environment of exterior wall insulation materials,SiO₂aerogel is used as the matrix and inorganic insulation materials are used as the carrier to prepare SiO₂aerogel/inorganic insulation composite board with good thermal insulation performance,good waterproof performance and certain mechanical properties,which has a broad application prospect for the field of exterior wall insulation.In this paper,SiO₂ aerogel/inorganic composite insulation board with excellent thermal insulation,waterproofness and certain mechanical strength was prepared using SiO₂aerogel as the matrix,foam glass and expanded perlite as the carrier,and it was applied to the building exterior wall in cold areas.The main work of this paper includes:The orthogonal test was designed to configure SiO₂ aerogel modified solution,SiO₂aerogel powder was added to absolute ethanol,and silane coupling agent KH550 and Tween 80 were added respectively,and finally SiO₂ aerogel powder,silane coupling agent KH550 and Tween 80 were configured according to the mass fractions of 6%,5%and 10%as the best proportions,and the SiO₂ aerogel modification solution with the best modification effect could be configured.Foam glass and expanded perlite were used as carriers,SiO₂ aerogel was used as matrix,foam glass and expanded perlite were placed in SiO₂ aerogel modified solution by atmospheric pressure infiltration,and then SiO₂aerogel/foam glass and SiO₂ aerogel/expanded perlite composite insulation board were obtained by atmospheric pressure drying.The results showed that under the best process conditions,the short-term water absorption of SiO₂ aerogel/foam glass composite board was 0.135kg/m²,which was reduced by 28.9%,the thermal conductivity was0.043W/m·K,which was reduced by 25.9%,and the compressive strength was 753k Pa（failure load）.The short-term water absorption of SiO₂ aerogel/expanded perlite composite plate was 2.9 kg/m²,which decreased by 66.3%,the thermal conductivity was0.039 W/m·K,which was reduced by 18.75%,and the compressive strength was 5765k Pa（failure load）.Then,the prepared SiO₂ aerogel/inorganic insulation board was further applied to a residential building in cold area,and the energy-saving effect of SiO₂ aerogel/inorganic insulation board in cold area was studied and compared with the exterior wall insulation materials commonly used in cold areas.Through the De ST building energy consumption simulation software,the energy consumption model of residential buildings was established,and the energy saving rates of six different thermal insulation systems of two composite insulation boards（SiO₂ aerogel/foam glass and SiO₂ aerogel/expanded perlite）,organic insulation materials（EPS and XPS）and inorganic insulation materials（foam glass and expanded perlite）were selected in Xi’an,a cold region.The results show that compared with the absence of insulation,the energy saving rate of building thermal indicators that can be achieved by the above six insulation systems reaches 15%～25%.Compared with unmodified inorganic insulation materials,the energy-saving rate of SiO₂aerogel/inorganic insulation board has been greatly improved,which is close to or even better than organic insulation materials.Through the above research,the modification process of SiO₂ aerogel for inorganic insulation materials has high value in the production and application of exterior wall insulation materials,and has certain reference significance for the application of SiO₂aerogel/inorganic composite insulation board in the construction field of cold regions.