饰面砂浆泛碱性试验方法研究

Research on the efflorescence test method of decorative render for out-wall

现行行业标准JC/T 1024—2007《墙体饰面砂浆》中的"抗泛碱性"试验方法存在缺陷。研发的电控淋水装置可以很好地测试试样的泛碱性。试样淋水时间对泛碱程度影响较大,淋水时间应在30 min以上;淋水时,环境湿度对试样泛碱程度影响不大。淋水后试样的干燥制度对泛碱有较大影响,烘干的比自然干燥的泛碱严重;烘干时,烘箱门关闭与烘箱门开度约15°的试件比较,后者泛碱程度大于前者;烘箱温度分别为50℃、70℃时,泛碱程度差异不大,但70℃时试件明显变色。间接证明了泛碱的主因是水泥水化产物中Ca(OH)_2的碳化。研究结果可为JC/T 1024—2007的修订提供直接的依据,也可为相关方提供一定的借鉴。

There are lots of defects on the efflorescence test method in the JC/T 1024-2007 ＂Decorative render ＆ plaster for wall＂. The sample efflorescence could be well tested using the self-made water spray device. The sample effloreseenee is much in flueneed by ihe spray time and the spray time should be more than 30 rain;the ambient humidity has little effect on effloreseenee of render when under spraying, the drying system after spraying has great effect on effflorescence,the efflorescence by oven drying is more severe than by natural curing;the door of the drying oven should be open with about 15 ~. The efflorescence is not significant whether the temperature is 50 ~ or 70 ~C, but the sample color of the latter is changed obviously. It is indirectly certified that the main reason of the efflorescence is the earbonation of Ca（OH）2 from the hydrating of the eement. The test results provide direct evi- denee for the revision of JC/T 1024--2007,and also can be used for eertain reference for relevant parties.