Mechanisms of Combined Effects of AAR and Reinforcement Corrosion on Concrete

通过详细的实验研究外加海水和氯化钠溶液对ASR的影响，以及加盐和不加盐砂浆中ASR的化学反应过程，可以对氯化钠和海水促进ASR的机理提出新的思路。阐明了试件表面不同深度的孔溶液组成随时间的变化及其与试件中钢筋锈蚀的关系。另一个重要结果是研究了含有亚硝酸盐的砂浆中亚硝酸盐的有效性与孔隙溶液组成之间的关系。主要结果如下：(1)浸泡360d后，0.51 MmNaC l溶液中砂浆中的Cl-/OH-比大于海水中的。致密的层状文石和水镁石的形成可能会阻碍氯离子侵入砂浆圆筒和从砂浆圆筒中渗出OH-离子。(2)从孔溶液组成来看，反应中钢筋的腐蚀程度要大得多。含有骨料的砂浆是意想不到的。(3)用更多的活性骨料替换砂浆中的标准砂，除1例外，钢筋的锈蚀程度较小。含活性集料的砂浆在海水和氯化钠溶液中的腐蚀抑制似乎是由于钢筋周围形成均匀的ASR凝胶层所致。

We could propose a new thought on the mechanisms of the promotion of ASR due to sodium chloride and sea water through detailed experiments concerning the effects of externally supplied sea water and sodium chloride solution on ASR and the process of ASR chemical reaction in mortars with and without NaCl. Furthermore, the changes in pore solution composition with time at various depths from the surfaces of specimens and their relation to the corrosion of reinforcement steel bars in the specimens were elucidated. Another important result was a finding on the relation between the effectiveness of nitrites and the pore solution composition in mortars containing the nitrites.The major results obtained were summarized as follows ;(1) The Cl-/OH- ratios in mortars in 0.51Mm NaCl solution were greater than in sea water at 360 daysafter, immersion. The formation of dense layrs aragonite and brucite might hinder the intrusion of the Cl- ions into mortar cylinders and the leakage of OH- ions from them.(2) From a point of view of the pore solution composition, far greater corrosion degree in steel bars in reactive. aggregate-containing mortars was unexpected.(3) Replacement of greater amounts of reactive aggregate for standerd sand in mortars resulted in less degree of corrosion in steel bars except one case. The depression of corrosion in reactive aggregate-containing mortars in sea water and NaCl solution appears to result from the formation of homogeneous ASR gel layrs surrounding the steel bars.