干湿循环作用下混凝土抗氯离子侵蚀研究

本文研究了混凝土在干湿循环-盐溶液耦合作用下，氯离子在混凝土不同深度处的浓度分布。结果表明，与自然浸泡盐溶液腐蚀方式相比，干湿循环作用加速了自由氯离子在混凝土内部的积累。干湿循环20次时，相对于长期浸泡方式，混凝土中不同深度氯离子质量分数增加96．8％～127．5％。同时试验表明，水灰比对于氯离子在混凝土中的传输有显著影响，低水灰比的混凝土其结构较为致密，从而提高了混凝土的抗氯离子性能。混凝土中矿粉的掺入能显著降低混凝土内部的自由氯离子浓度。混凝土中掺入粉煤灰，在早期粉煤灰的火山灰效应不显著，因而早期抗氯离子侵入性能不明显。

Study on chloride ion ingress into concrete under drying-wetting cycles

In this paper,the distribution of chloride ion in different depths of concrete under drying-wetting cycles and saline solution coupled reaction has been studied.The experiment results show that drying-wetting cycles accelerate the free chloride ion accumulation in concrete compared with long-period immersion in saline solution.Compared with immersion,the mass fraction of chloride ion in different depths increase 96.8%～127.5% after 20 drying-wetting cycles.Experiment results also indicate the W/C(water to cement ratio) has a significant impact during the transport of chloride ion in concrete.Due to the compaction structure with low W/C,the concrete has a good anti-chloride ion performance.The free chloride ion concentration can reduce remarkably when introduce GGBFS(Ground Granulated Blast Furnace Slag).Due to unremarkable pozzolanic activity of fly ash in concrete at an early age,the capability of anti-chloride ion ingress is not obvious of early period.