不同孔隙率下加气混凝土吸放湿性能试验研究

Experimental study on moisture adsorption and desorption properties of autoclaved aerated concrete with various porosities

为研究孔隙率对加气混凝土中湿分迁移特性的影响,采用恒温恒湿箱控制环境相对湿度和温度的方法对具有三种不同孔隙率的加气混凝土试样的动态吸湿和放湿过程进行了测试。研究结果表明,在等温吸湿过程中,加气混凝土试样的孔隙率越大,其含水率增长速率越大且平衡含水率也越高;而在等温放湿过程中,孔隙率越大的试样含水率下降速率越快且平衡含水率也越小,达到放湿平衡所需的时间则随相对湿度的提高而增长。比较不同环境温度下的吸放湿过程可知,较低的环境温度使得试样达到平衡状态所需的时间显著增加。此外,根据等温吸湿数据给出了加气混凝土吸湿平衡含水率随相对湿度变化的分段函数拟合公式。

In order to explore the effect of porosity on the moisture transfer characteristics of autoclaved aerated concrete （AAC） , the dynamic moisture adsorption and desorption processes of AAC samples with three different porosities were tested by controlling the environmental relative humidity and temperature via a climatic chamber. It was shown that during isothermal moisture adsorption, the AAC sample with a higher porosity lead to a faster increase in its moisture content and a higher equilibrium moisture content. However, during isothermal moisture desorption, as a consequence of increasing the porosity, the decreasing rate of the moisture content became greater with a lower equilibrium moisture content and the time elapsed to reach a desorption equilibrium became longer with increasing the relative humidity. A comparison among the adsorption/desorption processes under different environmental temperatures revealed that a longer time was required for the samples to reach the equilibrium state at a lower environmental temperature. In addition, based on the isothermal desorption data, a piecewise correlation was proposed for the desorption equilibrium moisture content of the AAC samples as a function of relative humidity.