Understanding the isothermal moisture absorption and desorption characteristics of building thermal insulation materials and how they affect thermal conductivity, is curial for accurate building thermal design and energy-saving calculation. In this paper, five types of building thermal insulation materials are selected for investigation. First, the variation trend of the equilibrium mass moisture content of materials in different moisture absorption and desorption stages is studied employing the saturated salt solution method and the constant temperature and humidity box method, and the effect of temperature on the moisture absorption and desorption processes is evaluated. Additionally, the applicable model of the material in the moisture absorption and desorption process is obtained through a fitting analysis of the experimental data. Finally, the influence of the material’s moisture absorption and desorption characteristics on the thermal conductivity is analyzed using the transient thermal conductivity test method. The results highlight that there is a need to consider the moisture absorption and desorption processes to accurately determine the wet material thermal conductivity, and the hysteresis effect of the material in the moisture absorption and desorption processes is directly related to its microstructure and the relative humidity at the initial moisture desorption. At a temperature of 25 , the autoclaved aerated concrete exhibits its highest hysteresis rate of thermal conductivity during the moisture desorption process of third stage, reaching 13.2%.

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建筑保温材料吸放湿特性及预测模型分析

了解建筑保温材料的等温吸放湿特性及其对导热系数的影响，对于精确的建筑热设计和节能计算具有重要意义。本文选取五类建筑保温材料进行研究。首先采用饱和盐溶液法和恒温恒湿箱法研究了物料在不同吸放湿阶段的平衡质量含水率的变化趋势，得出温度对吸放湿过程的影响为评价。另外，通过对实验数据的拟合分析，得到了材料吸放湿过程的适用模型。最后利用瞬态导热系数测试方法分析了材料的吸放湿特性对导热系数的影响。结果表明，准确确定湿材料的导热系数需要考虑吸湿和放湿过程，而材料在吸湿和放湿过程中的滞后效应与其微观结构和相对湿度直接相关。初始水分解吸。温度为25℃时，蒸压加气混凝土在第三阶段解吸水分过程中表现出最高的导热滞后率，达到13.2%。