多孔烧结陶片吸水特性实验方法

Experimental methods for water absorption characteristics of porous firing clay tiles

建筑被动蒸发降温效益以多孔材料吸水特性为基础。以广泛应用的多孔烧结陶片为例,相关参数测试方法标准并不一致。笔者参考国际标准采用"单面浸泡法"测试了3种多孔陶片的毛细吸水系数及毛细饱和含水率,实验结果表明,在第1吸水阶段,材料孔隙率与毛细吸水系数及毛细饱和含水率呈现显著正相关关系。参考中国标准,采用"整体浸泡法"和"真空饱和法"测试了上述3种材料在水中浸泡24h后的含水率,并与"单面浸泡法"测试结果进行了对比研究,结果显示,后者实验结果分别比前两者低3.25%和21.58%。研究表明,第1阶段吸水速率高的材料具有更高毛细饱和含水率,此种陶片更适宜蒸发降温应用。测试方法上单面浸泡法优于整体浸泡法。采用重复性误差衡量实验精确度,分析结果表明上述实验的重复性误差均低于2.40%。

Efficiency of building passive cooling is based on the water absorption characteristics.Illustrated by the example of porous firing clay tiles,test methods are different between national and international standards.Capillary water absorption coefficients and capillary saturated water contents of three kinds of porous face tile are measured through partial immersion method referred to the international standard.The results show that both porosity/capillary absorption coefficient and porosity/capillary saturated water content have a linear positive correlation.Water contents after 24 hours absorption are measured through integral immersion method referred to the national standard,and vacuum saturation method.The results are compared to those abtained through partial immersion.It is showed that the results of partial immersionis less than the results of integral immersion by 3.25%,and less than the results of vacuum saturation by21.58%.The result shows that higher capillary water absorption coefficients means higher capillary saturated water contents.The corresponding kind of tile is more suitable for passive cooling.For the test method,partial immersion is more appropriate than integral immersion.Repeatability errors of all the tests are under 2.40%,showing high precisions.