海洋环境中混凝土抗冻融循环试验研究

Research on the frost-resistant durability of concrete under sea water conditions

模拟海水盐溶液来研究海洋环境中混凝土的抗冻融循环性能.海水与淡水环境中混凝土冻融循环对比试验结果表明,海水加速高水胶比混凝土的腐蚀速度,主要表现为混凝土试件表面冻胀剥落,质量损失率增大.控制新拌混凝土含气量在6%±1%,同水胶比的普通混凝土和高性能混凝土抗冻耐久性相当.矿渣微粉的二次水化作用会降低硬化高性能混凝土的含气量,但气泡间隔系数仍低于200μm.为满足混凝土在海洋环境中抗冻耐久性要求,在保证混凝土气泡间隔系数低于300μm的同时,混凝土水胶比不宜大于0.40.

The frost-resistant durability of concrete is researched in simulated sea water conditions. Results of the concrete freezing and thawing cycle tests under sea water and fresh water conditions show that sea water accelerates corrosion of concrete with high water cement ratio. It mainly behaves that the concrete surface flakes away, and mass loss increases. When fresh concrete air content in volume is controlled to 6% ± 1% , the frost-reslstant capabilities of ordinary and high performance concrete with the same water cement ratio are equivalent. Because of the second hydration of blast-furnace slag, the air content of hard high performance concrete is depressed, but its air bubble distance coefficients are lower than 200 μm. In order to meet a demand for concrete durability of frostresistance under sea water conditions, concrete air bubble spacing coefficient should be lower than 300 μm, and concrete ratio of water to cement should be less than 0.40.