ABSTRACT Existing models for predicting the time to the commencement of serious reinforcement corrosion in chloride conditions provide results that do not compare well with long-term observations and practical experience for actual concrete structures. Many high-quality concrete structures show little or no evidence of serious corrosion, even after decades of exposure to chloride conditions. Earlier it was proposed that the mechanisms for corrosion initiation differ from those for long-term corrosion. This is reviewed. New research shows corrosion initiation is dominated by the presence of air voids adjacent to the reinforcement. For good concretes this is mainly a short-term transient effect. Long-term active corrosion is the direct result of the usually slow loss of concrete alkalinity, a process accelerated by chlorides. This, rather than direct chloride attack, is the cause of damaging reinforcement corrosion. It is argued also that the role of concrete cracking intersecting the reinforcement must be reconsidered. These new interpretations open up the way for improved modelling and prediction of ‘chloride-induced’ corrosion.

中文翻译：

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钢筋混凝土结构耐久性建模

摘要 用于预测氯化物条件下严重钢筋腐蚀开始时间的现有模型提供的结果与实际混凝土结构的长期观察和实践经验不能很好地进行比较。即使在暴露于氯化物条件下数十年之后，许多高质量的混凝土结构也很少或根本没有严重腐蚀的迹象。早先有人提出腐蚀引发的机制不同于长期腐蚀的机制。这是审查。新的研究表明，腐蚀的开始主要是由与钢筋相邻的气孔的存在决定的。对于好的混凝土，这主要是一种短期的瞬态效应。长期活性腐蚀是混凝土碱度通常缓慢损失的直接结果，氯化物加速了这一过程。这，而不是直接氯化物侵蚀，是破坏性钢筋腐蚀的原因。也有人认为，必须重新考虑与钢筋相交的混凝土开裂的作用。这些新的解释为改进“氯化物诱导”腐蚀的建模和预测开辟了道路。