Research On Thermal Performance Of Cast-in-Place Concrete Insulation And Structural Integration Wall

With the vigorous development of low-carbon energy-saving buildings,higher requirements are put forward for the optimization of building energy structure and construction mode.At present,the traditional external wall insulation system appears many problems in practical applications,mainly including different life between thermal insulation and structure,system cracking,system hollowing,system ooze water,system fall off and so on.In order to solve these problems,insulation and structural integration technology has been vigorously developed and popularized.This paper takes the cast-in-situ concrete insulation and structural integration wall as research object,explores the thermal performance of two kinds of integration walls.Firstly,the external formwork of cast-in-situ concrete insulation and structural integration wall with 3,6 and 9 connectors are experimentally studied,and the measured heat transfer coefficient of the wall is obtained and verified by simulation.The results show that the comparison error between simulation and calculation is within 5%,which meets the requirements of engineering calculation.Secondly,numerical calculation is used to analyze the influence of reinforced ribs in the external formwork cast-in-place concrete insulation and structural integration wall on its heat transfer coefficient,and then the overall thermal performance of the wall with extruded board and graphite extruded board as insulation layer is analyzed.The change of heat transfer coefficient and the comprehensive correction coefficient of heat preservation material are obtained when the number of connectors is 6/m~2,8/m~2 and 9/m~2 respectively.Then,the influence of the web bars and the connectors in the cast-in-situ concrete built-in insulation and structural integration wall on the heat transfer coefficient is studied,and then the thermal performance of wall with the thermal insulation layer of extruded board,graphite extruded board,molded board and graphite molded board is analyzed respectively.Finally,the influence of the web bars and the connectors on the heat transfer coefficient and the equivalent comprehensive correction coefficient of thermal insulation material are obtained when the thickness of the thermal insulation layer are 80 mm-110 mm.The heat transfer coefficients of the external formwork cast-in-situ concrete insulation and structural integration walls with extruded board insulation layer and the cast-in-situ concrete built-in insulation and structural integration wall are calculated,and then the influence of connectors with different heat conductivity coefficients on the heat transfer coefficient of these two walls is studied.Finally,aim at the heat transfer of the thermal bridge at the joints between exterior wall and overhang of the cast-in-situ concrete built-in insulation and structural integration wall,a three-dimensional steady state heat transfer model is established.Aided by the three-dimensional steady state simulation method,the wall heat transfer condition of the 75%energy-saving and ultra-low energy buildings at different outdoor temperatures is simulated with the consideration of the web bars and the connectors.Moreover,the temperature distribution of the exterior wall is analyzed to estimate whether there are thermal defects.In conclusion,this paper systematically investigated the thermal performance of cast-in-situ concrete insulation and structural integration wall and the thermal defects of the overhang.The findings will have guiding significance for product research and development,building energy-saving design,standard establishment,atlas compilation and so on.