盐分对水泥砂浆中水蒸气迁移的实验研究

Experimental Study on the Effect of Salt on Vapor Migration in Cement Mortar

滨海建筑受盐分侵蚀,其墙体材料的水蒸气迁移性能对建筑能耗有重要影响。因此,对于海洋大气中的建筑,有必要研究盐对建筑材料水蒸气渗透性能的影响。通过设置不同含盐量的水泥砂浆试件,测量其在不同湿度水平下的水蒸气渗透性能,得出水蒸气渗透系数随含盐量和相对湿度变化的规律,同时提出各工况下含盐水泥砂浆的水蒸气渗透系数代表值。实验结果表明:材料含盐后水蒸气渗透系数随湿度增加而增加的规律并未改变;在给定湿度的条件下,水蒸气渗透系数随着盐分含量的增加,先增加后减少。在高湿中盐工况下盐分促进水蒸气迁移的效果最明显,相较于未含盐时最高可达25.3%;在低湿高盐工况下抑制作用最明显,最低可达40.3%。此外,将本实验全工况分为9个区域,并确定了各区域的水蒸气渗透系数的代表值。探明了水泥砂浆受盐分侵入后水蒸气渗透系数的变化规律,并且为进一步探究含盐材料的水分迁移特性提供了方法借鉴。

Coastal buildings are eroded by salt, and the water vapor migration performance of wall materials has an important impact on building energy consumption. Therefore, for buildings in the ocean-atmosphere, it is necessary to study the effect of salt on the water vapor permeability of building materials. By setting cement mortar specimens with different salt content and measuring their water vapor permeability at different humidity levels, the variation law of the water vapor permeability coefficient with salt content and relative humidity is obtained. At the same time, the representative values of the water vapor permeability coefficient of salt-containing cement mortar under various working conditions are proposed. The experimental results show the law that the water vapor permeability coefficient increases with the increase of humidity has not changed after the material contains salt;At the condition of given humidity, the water vapor permeability increases firstly and then decreases with the increase of salt content. Under the condition of high humidity and medium salt, the effect of salt on water vapor migration is the most obvious, which is up to 25.3% compared with that without salt;Under the condition of low humidity and high salinity, the inhibition effect is the most obvious, with a minimum of 40.3%. In addition, the whole working condition of this experiment is divided into nine regions, and the representative values of the water vapor permeability coefficient in each region are determined. This study proved the variation law of the water vapor permeability coefficient of cement mortar after the salt intrusion and provided a method reference for further exploring the water migration characteristics of salt-containing materials.