Study On Physical And Mechanical Properties Of Silicon Based Aerogel Plate In Different Environments

Building energy consumption accounts for a high proportion of social energy consumption year after year.The use of new thermal insulation materials and the reduction of building energy loss are the main means to achieve building energy conservation.As the current research hotspot,aerogel materials provide a new way to solve the problem of building energy consumption.However,at present,aerogel materials are rarely used in wall insulation,and comprehensive research is needed to provide a theoretical basis for their use in the field of building insulation.In this paper,the performance test of fiber reinforced silicon based aerogel board in alkaline environment,humidity environment and freeze-thaw environment is carried out.The main research contents and results are as follows:(1)By using 5% Na OH solution to carry out alkali environment resistance tests for 0 d,7 d,14 d,21 d and 28 d respectively,the change rule of physical and mechanical properties of aerogel plate after immersion in alkaline environment for different periods was studied.The results show that the physical and mechanical properties of the aerogel plate decrease with the increase of immersion time.At the beginning of immersion,the physical and mechanical properties of the aerogel plate rapidly decline,and the decline rate begins to slow down after 14 days of immersion.At this time,the bending and compression properties of the aerogel plate have decreased by more than 90%,and the vibration mass loss rate has increased significantly;After immersion for 28 days,the aerogel plate completely lost its bending resistance,the compression strength and compression elastic modulus decreased to about 3% of the 0 d sample,and the vibration mass loss rate decreased.(2)The change rule of physical and mechanical properties of aerogel plate after moisture absorption saturation under different humidity conditions was studied by using a damp heat test chamber to place the aerogel plate in the environment with temperature of 20 ℃ and relative humidity of 0%,30% and 90%.The results showed that the physical and mechanical properties of the aerogel plate decreased with the increase of environmental humidity and water content,The bending and compression properties of aerogel plate decreased significantly at 30% ambient humidity,with an average decrease of 20%;When the ambient humidity continues to rise to 90%,the bending and compression properties of the aerogel plate decrease slightly,with an average decrease of 10%;The rate of vibration mass loss increases with the increase of environmental humidity.(3)The physical and mechanical properties of aerogel plate after different freezethaw cycles were studied by using the freeze-thaw test chamber for 0,100,200 and 300freeze-thaw cycles.The results show that the physical and mechanical properties of the aerogel plate decrease with the increase of freeze-thaw cycles.The moisture content can reach 10 times of the natural state after freeze-thaw cycles.The bending properties and compression properties decline linearly,and they decrease by 40% and 10%respectively after 300 freeze-thaw cycles;The rate of vibration mass loss increases with the increase of freeze-thaw cycles.(4)By comparing and analyzing the differences of physical and mechanical properties of aerogel plates in three low-quality environments,it can be seen that alkaline environment has the largest negative impact on the physical and mechanical properties of aerogel plates,followed by freezing and thawing environment,and humidity environment has the smallest impact.The long-term exposure of aerogel plates to alkaline environment or freezing and thawing environment will lead to the physical and mechanical performance parameters of aerogel plates being lower than the specification requirements.Therefore,aerogel plates are used in cold regions In the wall insulation project in the seasonal freezing area,or when directly contacting with non low alkalinity cement in the project,the corresponding isolation or protection measures shall be taken for the aerogel board in combination with the actual working conditions.