砂及新拌混凝土中氯离子含量快速测试方法的研究

Study on the rapid determination methods of chlorine ion content in sand and fresh concrete

利用可快速测定水溶性氯离子含量的速测条(简称速测条法),对上海市某混凝土搅拌站的砂及新拌混凝土中的氯离子含量进行测试。并与硝酸银滴定法、电极电位法进行对比,从3种方法的关联性,速测条法测试的重复性、温度的敏感性和操作的便捷性方面进行对比研究。当测试砂时,速测条法与硝酸银滴定法有较高的相关性,但在混凝土测试过程中,二者的相关性较低;速测条法对同一砂样测试的重复性好;温度敏感性小,4~40℃范围内与25℃测试的结果偏差不超过±10%;测试速度快,30min可完成对砂、新拌混凝土中氯离子含量的测试。

In this paper,a fast test method commonly used to measure chlorine ion content in sand and fresh concrete from a fresh concrete mixing station in Shanghai.This method can determinate water-soluble chloride ion content rapidly with the test strip,which can be called fast test strip method.And,after comparing with the silver nitrate titration method and the chloride ion selective electrode method;a comparative study was conducted from four aspects,which was the correlation between the three methods,the repeatability,temperature sensitivity and convenience of the fast test strip method.It was found that there was a high correlation between the fast test strip method and the silver nitrate titration method when testing sands,but the correlation between them was lower when testing concrete.The fast test strip method had a good repeatability to test the same sample of sand.In the range of 4~40℃,the deviation from the test result of 25℃does not exceed±10%.Also,this method was the fastest one,the content of chloride in sand or fresh concrete can be tested in 30 minutes.