RESEARCH ON HEAT TRANSFER MECHANISM AND THERMAL PERFORMANCE OF WHEAT STRAW FLY ASH CONCRETE

A large number of rural residential buildings in the world did not take effective thermal insulation measures. The poorthermal insulation performance of the envelope led to low indoor temperatures in winter, and energy consumption was huge.The purpose of this study was to explore the effect of wheat straw and fly ash incorporated into concrete on its thermalproperties, and to provide a low-cost and energy-efficient solution for rural building wall materials. The experiment involvedpreparing concrete block samples containing different doses of fly ash and straw, building an experimental platform todetermine compressive strength and thermal conductivity, and simulating different humid environments using a saturatedsaline solution to analyse the effect of moisture content on thermal conductivity. The effect of moisture content on thermalconductivity was analysed by simulating different humidity environments with saturated salt solution. Combined with data fittingand comparative analysis, the mechanism of straw admixture, morphology and humidity on the material properties wasrevealed. The study showed that the thermal conductivity of wheat straw fly ash concrete decreased gradually as the contentof fly ash and straw increased, and the larger the content, the smaller the thermal conductivity. The thermal conductivity ofwheat straw fly ash concrete increased significantly with the increase in air humidity, and the relationship between moisturecontent and thermal conductivity was closely related to the content of straw and fly ash. The incorporation of fly ash and strawin concrete effectively improved the thermal insulation performance of building materials, and was an effective alternative forimproving building energy efficiency and reducing carbon emissions