在硫酸盐环境下冻融-干湿循环对混凝土的影响

Study on sulphate environment under freeze-thaw and dry-wet cycling of concrete

采用单一冻融、单一干湿和冻融-干湿循环交替作用的方法,研究了混凝土在不同浓度的硫酸盐溶液中的耐久性能。试验采用100 mm×100 mm×400 mm试件直立完全浸泡进行干湿循环。研究表明,硫酸盐冻融-干湿循环作用下,溶液浓度对冻融破坏的影响存在临界值C=4.7%。当C≤4.7%时,冻融-干湿破坏随着溶液浓度的提高相对动弹性模量损失增大,而质量损失减小;当C>4.7%时,溶液浓度对冻融破坏或冻融-干湿复合破坏影响不大。冻融-干湿破坏力最强、冻融破坏次之,干湿破坏最为缓慢;且干湿循环使冻融循环破坏加剧。试验发现15%FA取代水泥,混凝土抗硫酸盐腐蚀最佳。

Single freeze-thaw cycles, single wet-dry cycles, and freeze-thaw and wet-dry cycles studied by means of concrete in sulfate solutions of different concentrations of durability.Experiment with 100 mm× 100 mm×400 nun upright specimen completely immersed for wet and dry cycle.Studies have shown that sulfate freeze-thaw and wet-dry cycles,the concentration on the impact of freeze-thaw cycles damage there is critical value C=4.7%,when C ≤4.7%, the freeze-thaw and wet-dry cycles destruction increased as the relative concentration the greater the loss of dynamic elastic modulus, while the smaller mass loss, when C〉4.7%, the concentration of the freeze-thaw or freeze-thaw and wet-dry cycles damage has little effect;the freeze-thaw and wet-dry cycles destroy〉freeze-thaw cycles damage〉destruction of wet-dry cycles, wet and dry cycles to promote increased freeze-thaw damage; study found 15% FA replacement of cement,concrete resistance to sulfate corrosion of the best.