混凝土质量控制过程中水溶性氯离子含量检测方法的对比研究

Comparative study on the detection methods of water soluble chloride contents in the concrete process of quality control

采用现行标准中的不同检测方法对混凝土拌合物及早期硬化混凝土中的水溶性Cl^-含量进行了对比研究。结果表明,参照标准JTJ 270、JGJ/T 322附录A中的两种Cl^-选择电极法测得的混凝土拌合物水溶性Cl^-含量测试值与理论值偏差基本都在20%以内,其中JGJ/T 322附录A的测试结果更接近理论值,而采用JGJ/T 322附录B的硝酸银滴定法得到的测试值与理论值偏差均小于10%。对于早期硬化混凝土,相比标准GB/T 50344附录C的电位滴定法,采用JGJ/T 322附录C中的硝酸银滴定法得到的水溶性氯离子含量与理论值更接近,其偏差均小于10%,且C30、C60两种强度等级混凝土硬化后水溶性Cl^-含量随着龄期延长而减少。

Water soluble chloride content of fresh and hardened concrete were studied comparatively with different testing method of the current standard.The results showed that the deviation of water soluble chloride contents between tested value and theoretical value in fresh concrete were both within 20% when referencing the chloride selective electrode method of JTJ 270 and JGJ/T 322 appendix A, and the tested value according to JGJ/T 322 appendix A was closer to the theoretical value.Also,all of the tested value according to JGJ/T 322 ap pendix B （silver nitrate titration method） was within 10%.For hardened concrete at early age, the tested value according to the silver ni- trate titration method of JGJ/T 322 appendix C was closer the theoretical value comparing the tested value according to GB/T 50344 ap- pendix C,both of the deviation were within 10%.In addition,the water soluble chloride content of C30 and C60 hardened concrete were decreased with the increase of age,