One of the challenges to reinforced concrete slab in bridge is the 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 the coarse aggregates to investigate the effect of ASR on rebar corrosion. It was found that the combined effects of chloride attack and ASR adversely affected the corrosion resistance of the high early strength concrete. Fly ash concrete had excellent performance in terms of corrosion resistance and ASR mitigation. Results also showed that a widely used electrochemical technique known as the half-cell potential test also can be used to diagnose corrosion of the double-layer reinforced concretes. Concrete specimens containing SCMs with no ASR threat showed no signs of steel bar corrosion and significantly low chloride diffusion coefficients after three years.

中文翻译：

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氯化物侵蚀和ASR下蒸汽养护混凝土中钢筋的腐蚀评价

桥梁中钢筋混凝土板面临的挑战之一是除冰盐对钢筋腐蚀造成的劣化。为了模拟混凝土板在冬季从桥板顶面经受除冰盐渗透，具有双层钢筋的高强度蒸汽养护混凝土暴露于 10% 氯化钠溶液中以研究钢筋腐蚀。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渣作为补充胶凝材料 (SCM) 的混凝土。对于高早强混凝土和粉煤灰混凝土，将碱活性安山岩与粗骨料混合，以研究 ASR 对钢筋腐蚀的影响。结果表明，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。粉煤灰混凝土在抗腐蚀和缓解 ASR 方面具有优异的性能。结果还表明，一种广泛使用的电化学技术，称为半电池电位测试，也可用于诊断双层钢筋混凝土的腐蚀。含有无 ASR 威胁的 SCM 的混凝土样品在三年后没有显示出钢筋腐蚀的迹象，并且氯化物扩散系数显着降低。结果还表明，一种广泛使用的电化学技术，称为半电池电位测试，也可用于诊断双层钢筋混凝土的腐蚀。含有无 ASR 威胁的 SCM 的混凝土样品在三年后没有显示出钢筋腐蚀的迹象，并且氯化物扩散系数显着降低。结果还表明，一种广泛使用的电化学技术，称为半电池电位测试，也可用于诊断双层钢筋混凝土的腐蚀。含有无 ASR 威胁的 SCM 的混凝土样品在三年后没有显示出钢筋腐蚀的迹象，并且氯化物扩散系数显着降低。