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Preventive Measures and Mechanisms of Concrete Deterioration due to ASR under Marine Environments

海洋环境下ASR混凝土劣化的预防措施及机理

基本信息

批准号：
02650333
负责人：
KAWAMURA Mitsunori
金额：
$ 1.41万
依托单位：
Kanazawa University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1990
资助国家：
日本
起止时间：
1990 至 1991
项目状态：
已结题

项目摘要

The results obtained in this fiscal year are divided into the two categories, i. e. the one on the reaction products and expansion behavior in opal-bearing mortars immersed in NaCl solutions and an artificial sea water, exposed to a marine environment.The major results obtained in the former experiments are summarized as follows ;(1) Great amounts of Ca (OH)2 in all mortars with the opal were dissipated during the immersion in 1 N NaCl solution.(2) Great amounts of the chloride-bearing ettringite was found in the portions as well as in voids in opal-bearing mortars immersed in 1 N NaCl solution for longer than one vear. It is likely that the greater the expansion of mortars, the greater the amount of ettringite found in the mortars.(3) The concentration of NaCl solution in which mortar specimens were immersed, greatly influenced the expansion of mortars with relatively low alkali/opal ratio. However, in the range of high alkali/opal ratio, the concentration of the NaCl solution little influenced the expansion of the mortars.The following new findings were obtained in the latter experiments which have been successively carried out for these several years.(1) Rapid expansions occurred on the exposed surfaces in reactive aggregate-bearing concrete specimens with the unit cement content of 450kg/cm3. This fact suggests that spray of sea water is influencing the expansion of the concrete due to the alkali-silica reaction.(2) There is found a trend that the less the alkali content in the concretes, the greater the expansion of the concretes exposed to the marine environment.

本财政年度取得的业绩分为两类，即：e.实验结果表明：（1）在1 N NaCl溶液中，蛋白石砂浆中Ca（OH）_2大量散失;（2）在1 N NaCl溶液中，蛋白石砂浆中Ca（OH）_2大量散失; (2)大量的含氯钙矾石被发现的部分，以及在空隙中的蛋白石轴承砂浆浸泡在1 N的NaCl溶液中超过一个vear。很可能迫击炮的膨胀越大，迫击炮中发现的钙矾石的量就越大。(3)砂浆试件浸泡的NaCl溶液浓度对碱/蛋白石比相对较低的砂浆的膨胀有很大影响。但在高碱/蛋白石比范围内，NaCl溶液浓度对砂浆的膨胀影响不大。(1)单位水泥用量为450 kg/cm ~ 3的活性骨料混凝土试件的暴露面发生了快速膨胀。这一事实表明，由于碱-硅反应，海水的喷射影响了混凝土的膨胀。(2)发现混凝土中的碱含量越少，暴露于海洋环境的混凝土的膨胀越大。