One of the challenges to reinforced concrete slabs in bridges is deterioration due to rebar corrosion by deicing salts. In order to simulate a concrete slab subjected to deicing salt penetration from the top surface of the bridge slab during winter, high-strength steam-cured concrete with double-layer reinforcements was exposed to 10% sodium chloride solution to investigate rebar corrosion. Five concrete mix proportions were prepared, including high early strength concrete and concrete containing fly ash and blast furnace slag as supplementary cementitious materials (SCMs). For both the high early strength and fly ash concretes, alkali active andesite in the pessimum proportion was mixed with coarse aggregates to investigate the effect of alkali–silica reaction (ASR) on rebar corrosion. It was found that the combined effects of chloride attack and ASR adversely affected the corrosion resistance of high early strength concrete. Fly ash concrete had excellent performance as to corrosion resistance and ASR mitigation. Results also showed that a widely used electrochemical technique known as the half-cell potential test can satisfactorily diagnose corrosion of double-layer reinforced concrete. Concrete specimens containing SCMs with no ASR threat showed no signs of steel bar corrosion and significantly low chloride diffusion coefficients after 3 years.

中文翻译：

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氯化物侵蚀和碱硅反应下蒸养混凝土中钢筋的腐蚀评价

桥梁钢筋混凝土板面临的挑战之一是钢筋因除冰盐腐蚀而退化。为模拟冬季桥板顶面除冰盐渗入混凝土板，将双层钢筋高强蒸养混凝土暴露于10%氯化钠溶液中，研究钢筋锈蚀情况。制备了五种混凝土配合比，包括高早强混凝土和含有粉煤灰和高炉矿渣作为辅助胶凝材料 (SCM) 的混凝土。对于高早强混凝土和粉煤灰混凝土，将最小比例的碱活性安山岩与粗骨料混合，以研究碱硅反应 (ASR) 对钢筋腐蚀的影响。结果发现，氯化物侵蚀和 ASR 的共同作用对高早强混凝土的耐腐蚀性能产生不利影响。粉煤灰混凝土在耐腐蚀和 ASR 缓解方面具有优异的性能。结果还表明，一种广泛使用的称为半电池电位测试的电化学技术可以令人满意地诊断双层钢筋混凝土的腐蚀。含有无 ASR 威胁的 SCM 的混凝土样本在 3 年后没有出现钢筋腐蚀迹象，并且氯离子扩散系数显着降低。结果还表明，一种广泛使用的称为半电池电位测试的电化学技术可以令人满意地诊断双层钢筋混凝土的腐蚀。含有无 ASR 威胁的 SCM 的混凝土样本在 3 年后没有出现钢筋腐蚀迹象，并且氯离子扩散系数显着降低。结果还表明，一种广泛使用的称为半电池电位测试的电化学技术可以令人满意地诊断双层钢筋混凝土的腐蚀。含有无 ASR 威胁的 SCM 的混凝土样本在 3 年后没有出现钢筋腐蚀迹象，并且氯离子扩散系数显着降低。