FREE AND WATER-SOLUBLE CHLORIDE IN CONCRETE
FREE AND WATER-SOLUBLE CHLORIDE IN CONCRETE
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DOI：
10.1016/0008-8846(95)00042-b
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发表时间：
1995-04-01
影响因子：
11.4
通讯作者：
KAYYALI, OA
中科院分区：
文献类型：
--
作者：
HAQUE, MN;KAYYALI, OA
两种方法被用来确定“自由”和“水溶性”氯离子浓度在四个不同强度等级的混凝土。每个等级的混凝土都有不同浓度的Cl-，如NaCl。在所有24个不同批次的混凝土中，所述混凝土具有按水泥重量计从0.2%变化至2%的所期望的Cl-浓度。第一种方法是分析从标本中表达的孔隙溶液，第二种方法是分析粉碎标本的倾析溶液。结果表明，Cl-和OH-离子的浓度，在所表示的孔溶液中测量代表其真实的自由离子浓度。此外，表达和滗析的解决方案的Cl-浓度被发现取决于（i）的钦佩的Cl-离子的浓度;（ii）混凝土的强度;（iii）存在或不存在的粉煤灰和（iv）存在或不存在的超增塑剂。因此，在倾析溶液和孔隙溶液中发现的Cl-浓度之间没有简单的关系。而粉煤灰的存在提高了混凝土的氯离子结合能力，超塑化剂的存在往往会降低它，本文的结论是，为了限制所造成的损害的Cl-在混凝土中，所钦佩的氯离子的总Cl-含量的上限，而不是Cl-的水泥重量的百分比应规定。
Two methods were used to determine the 'free' and 'water soluble' chloride ions concentration in four differing strength grade concretes. Each grade of concrete had varying concentration of Cl- admired as NaCl. In all 24 different batches of concretes were made with admired Cl- concentration varying from 0.2 to 2%, by weight of cement. The first method was the analysis of the pore solution expressed from specimens and the second by the analysis of the decanted solution of pulverised specimens. The results suggest that the concentration of Cl- and OH- ions as measured in the expressed pore solution represent their true free ion concentrations. Furthermore, the Cl- concentration of both the expressed and decanted solutions were found to depend on the (i) concentration of the admired Cl- ions; (ii) strength of the concrete; (iii) presence or absence of fly ash and (iv) presence or absence of a superplasticiser. Accordingly, there is no simple relationship between the Cl- concentration as found in decanted and pore solutions. Whereas the presence of fly ash improves the chloride binding capacity of a concrete, the presence of superplasticisers tends to lower it. The paper concludes that in order to limit the damage caused by Cl- in the concrete, an upper limit on the total Cl- contents of the admired chloride rather than the percentage of Cl- by the weight of cement should be prescribed.