海洋环境下耐蚀钢筋与普通钢筋混凝土柱服役性能演变规律及差异研究

The performance degradation of concrete structure induced by reinforcement corrosion will affect its safety, applicability, economy and other requirements. Adopting corrosion-resistant bar is one of the effective methods to improve performance of concrete structure and prolong service life of structure. The service performance evolution rule and difference on reinforced concrete columns of corrosion-resistant bar and conventional carbon bar will be basically studied against the background of marine environment and taking structure performance as research object. Firstly, the material properties of corrosion-induced damaged concrete and corroded bars, including corrosion-resistant reinforced bar and conventional carbon bar, will be studied, and the mechanics performance degradation model of two kinds of material will be set up. Then, the corrosion behavior characteristics of corrosion-resistant reinforced bar and conventional carbon bar within concrete will be studied by comparing experiments, both of the space and time differences in corrosion depassivation critical chloride ion concentration, composition and morphology of corrosion products, corrosion rate and other aspects will be revealed. Furthermore, the predicting method of service life on corroded reinforced concrete column will be put forward by further comparing and studying the performance degradation mechanism and the damaged cumulative process of service corrosion-resistant reinforced concrete column and conventional carbon bar reinforced concrete column, and the time-varying predicting model of bearing capacity on corrosion-induced reinforced concrete column will be set up. Finally, the improved effect and degree of corrosion-resistant reinforced bar on life cycle performance of concrete column will be reflected by comparing service life, bearing capacity, etc of two kinds of corroded reinforced concrete columns. The research results can provide theoretical basis for the design of durable and long service life’s concrete structure.

钢筋锈蚀引起的结构性能劣化关系到结构的安全、适用、经济等要求。采用耐蚀钢筋是提升结构性能，延长使用寿命的有效方法。本课题以海洋环境为背景，以结构性能为研究对象，对耐蚀钢筋与普通钢筋混凝土柱服役性能演变规律及差异进行基础科学研究。首先对锈蚀损伤混凝土及锈蚀钢筋（包括耐蚀钢筋和普通钢筋）材料性能进行研究，建立两种材料力学性能退化分析模型。然后通过试验对比研究耐蚀钢筋和普通钢筋在混凝土内的腐蚀行为，揭示二者在锈蚀脱钝临界氯离子浓度、腐蚀产物组成及形态、腐蚀速率等方面的时空差异性；进而对比研究服役耐蚀钢筋和普通钢筋混凝土柱的性能劣化机理、损伤累积发展变化过程，提出锈蚀钢筋混凝土柱使用阶段寿命预测方法，建立锈蚀钢筋混凝土柱承载力时变预测模型。最后通过对比两类锈蚀钢筋混凝土柱的使用寿命、承载力等指标，明确耐蚀钢筋对混凝土柱全寿命性能提升的效果及程度。其成果可为设计耐久、长寿命的混凝土结构提供理论依据。

普通碳素钢筋耐氯盐腐蚀性能差，采用其建造海洋环境下的混凝土结构极易产生锈蚀。钢筋锈蚀引起的结构性能劣化关系到结构的使用寿命及安全性能。如何提升海洋环境下混凝土结构的耐久性能、延长结构的使用寿命，是混凝土结构耐久性领域研究的重要课题。项目将新型低合金耐蚀钢筋运用于海洋环境下的混凝土结构，以达到提升结构性能、延长结构使用寿命的目的。基于此，课题开展了新型低合金耐蚀钢筋与普通碳素钢筋在混凝土内的腐蚀行为对比研究，获得了5Cr1Ni和5Cr两种低合金耐蚀钢筋及普通碳素钢筋在混凝土内脱钝的临界氯离子浓度、腐蚀速率、腐蚀产物组成及形貌等，揭示了低合金耐蚀钢筋耐腐蚀的机理；研究了锈蚀钢筋（包括耐蚀钢筋和普通钢筋）和锈蚀损伤混凝土材料性能退化规律，建立了两种材料力学性能退化分析模型，该模型可为结构性能退化分析提供理论依据；研究了混凝土结构使用寿命的影响因素，提出了耐蚀钢筋混凝土柱使用寿命预测方法；结合耐蚀钢筋及普通碳素钢筋腐蚀特性的研究成果，对不同保护层厚度、水灰比及外掺料情况下，耐蚀钢筋和普通钢筋混凝土柱进行寿命预测分析，两种低合金耐蚀钢筋的侵蚀寿命是普通碳素钢筋的3倍以上；针对混凝土结构中最为重要的柱式构件，模拟其在氯盐环境下的服役工作状态（即考虑荷载与氯盐环境共同作用），对比研究了服役耐蚀钢筋和普通钢筋混凝土柱的锈蚀开裂性能、损伤劣化机理，建立了锈蚀钢筋混凝土柱承载力退化分析模型。项目成果为经济型低合金耐蚀钢筋运用于海洋混凝土结构奠定了理论基础，具有十分重要的实际工程意义。