A Study on the Influence of Sodium Chloride on Alkali-aggregate Reaction

根据从周围环境向混凝土结构供应NaCl的假设进行的实验获得的结果总结如下：（1）从间歇供应NaCl的实验中，发现连续浸入NaCl溶液中的试样比间歇浸入溶液中的试样发生更大的膨胀。(2)在海岸和金泽大学校园内进行的试样暴露试验的结果如下：（a）碱-硅反应引起的损坏和膨胀程度在很大程度上取决于周围环境和温度提供的盐。(b)在自然环境下，开裂的发生之前，开始膨胀。(3)在含有NaCl和反应性骨料的混凝土中，碱-硅反应消耗的OH^-离子的量与仅含有反应性骨料的混凝土相比很小。(4)对于粉煤灰混凝土中的碱-硅酸反应，Cl-离子的存在降低了粉煤灰对碱-硅酸反应的抑制作用。

The summary of the results obtained from the experiments which have been carried out based on the assumption that NaCl is supplied to concrete structures from the surrounding environments is as follows;(1) From the experiments in which NaCl was supplied intermittently, greater expansions were found to occur in specimens which were continuously immersed in the NaCl solution than those immersed in the solution intermittently.(2) The results obtained from exposure tests of specimens at the sea coast and in the campus of Kanazawa University are as follows; (a) The degree of damages and expansions due to alkali-silica reaction greatly depends on the supply of salts from the surrounding environments and temperature. (b) Under natural environments, the occurrence of cracking was preceded by the initiation of expansion.(3) In concretes containing NaCl and a reactive aggregate, the amount of OH^- ions consumed by the alkali-silica reaction is small as compared to the concretes containing only the reactive aggregate.(4) As regards the alkali-silica reaction in concretes with fly ash, the inhibitive effect of fly ash on the alkali-silica reaction is reduced in the presence of Cl- ions.