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实验室和工程现场经常用硝酸银显色法检测混凝土中氯离子的迁移。有3种硝酸银显色法,即AgNO3+K2CrO4法、AgNO3+荧光素法以及AgNO3法,其中AgNO3法使用最广泛,因为AgNO3法测试结果和其他两种方法相似却比其他两种方法容易操作。硝酸银显色法测量的变色边界氯离子浓度在很大范围内变化,很多因素诸如混凝土碱度、硝酸银浓度、取样方法以及混凝土中氯离子分析方法等均会对变色边界氯离子浓度测试结果产生影响。采用硝酸银显色法测试的自由氯离子渗透深度以及通过变色边界自由氯离子浓度计算的表观扩散系数可以简单、快速地评价混凝土抗氯离子渗透性。
Laboratory and engineering sites often use silver nitrate colorimetric detection of concrete chloride ion migration. There are three kinds of silver nitrate colorimetric method, AgNO3 + K2CrO4 method, AgNO3 + fluorescein method and AgNO3 method, of which AgNO3 method is the most widely used, because AgNO3 method test results and the other two methods are easier to operate than the other two methods. Chloride ion concentration in the discoloration boundary measured by the silver nitrate colorimetric method varies widely. Many factors such as concrete alkalinity, silver nitrate concentration, sampling methods, and chloride ion analysis methods in concrete all affect the chloride ion concentration in the discoloration boundary test results Have an impact. The chloride penetration resistance of concrete is evaluated simply and quickly by the depth of free chloride penetration as measured by the silver nitrate colorimetric method and by the apparent diffusion coefficient calculated from the free chlorine ion concentration at the discoloration boundary.