氯离子腐蚀与碱集料反应双重破坏因素作用下混凝土膨胀行为的研究

RESEARCH ON CONCRETE EXPANSION BEHAVIOR SUBJECTED TO CHLORIDE CORROSION AND ALKALI-AGGREGATE REACTION

进行了氯化钠与碱集料反应双重破坏因素作用下混凝土的膨胀试验 ,目的是研究有氯化钠存在时碱集料反应的规律。试验中采用了高低两种不同碱含量的混凝土 ,浸泡液用 1NNaCl、1NNaOH及其分别与3%和 7%的NaCl的复合 ,碱集料反应环境温度为 38℃。研究结果表明 ,不论何种复合 ,高碱含量混凝土的膨胀均比低碱含量的混凝土高 ;对于低碱含量混凝土 ,在早期 ,1NNaCl溶液对混凝土膨胀的值高于 1NNaOH溶液 ,NaOH与NaCl的复合会导致更低的膨胀值 ,但在后期 ,结果正好相反 ;对于高碱含量混凝土 ,则不论在早期还是后期 ,1NNaCl溶液对混凝土膨胀的值均低于 1NNaOH溶液 ,NaOH与NaCl的复合会导致更高的膨胀值。

Concrete expansion test was conducted under the actions of sodium chloride and alkali-aggregate reaction,whose aim was to study the rule of alkali-aggregate reaction in the presence of sodium chloride.The concretes with high and low alkali contents were used for the test.1N NaOH, 1N NaOH+3% NaCl and 1N NaOH+7% NaCl were all used as the soak, and the ambient temperature of the reaction was 38℃.The results show that under all soaks the expansions of the high-alkali concrete are higher than those of the low-alkali concrete.At the period of low-alkali concrete, the expansion by 1N NaCl soak is higher than that by 1N NaOH, and a further lower expansion can be produced by NaOH+NaCl soak, yet at the late stage the results are exactly opposite; whereas at the early and late stages of high-alkali concrete, the expansion by 1N NaCl soak is lower than that by 1N NaOH, a further higher expansion can be produced by NaOH+NaCl soak.