STUDY ON DAMAGE TO CONCRETES ATTACKED BY SULFATES
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摘要: 对普通混凝土和高强混凝土在5.0%Na2SO4(质量分数,下同)、10%MgSO4溶液以及青海盐湖卤水溶液中的损伤失效规律、特点进行研究。结果表明:混凝土在Na2SO4溶液中浸烘循环腐蚀破坏,SO42-导致混凝土产生膨胀性破坏;其损伤劣化包括3个阶段:初始劣化段、性能改善段和性能劣化段。混凝土在MgSO4溶液、青海盐湖卤水中浸烘循环腐蚀损伤,腐蚀溶液中的SO42-和Mg2+共同作用导致混凝土产生剥落型破坏;其相对动弹性模量和重量随腐蚀时间先下降,后稳定,最后加速下降。此外,用SEM、能谱和XRD分析了混凝土在硫酸盐腐蚀作用下的腐蚀产物。Abstract: The damage processes of an ordinary concrete and a high strength concrete, attacked by solutions of 10% Na2 SO4 (in mass, the same below), 10%MgSO4 and Qinghai salt lake solution in cycles of drying-immersion are studied. The results show that the damage process of concretes attacked by Na2 SO4 exhibits a decreasing stage followed by improved performance stage, finally the failure stage because the SO2- 4 ions lead to expansion damage to concrete. Abrasion and mass loss of concrete are the main deterioration form when concrete exposed toMgSO4 solution or to Qinghai salt lake solutions, its relative dynamic elastic modulus and mass decreased first, then kept stable, lastly to failure. Moreover, corrosion elements of concretes attacked by sulfates are studied by SEM, EDS and XRD.
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Key words:
- concrete /
- sodium sulfate /
- magnesium sulfate /
- salt lake /
- microstructure
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