氯盐诱导合金钢筋锈蚀行为及其钢筋/混凝土界面特征演化机制研究

This research project is set according to the urgent demand of the long-life of the concrete structures and materials serviced in the severe corrosive environment. A new strategy is proposed aiming to the "bottleneck" problem of the corrosion-induced concrete cracking due to the limited corrosion resistance of the carbon-steel rebar, that the alloyed steel rebar with potential characteristics of “high corrosion resistance” and “lower rust expansion rate” is used to inhibit the rust expansion and cracking of the reinforced concrete structure. The project will be executed according to the slow corrosive-cracking process of the reinforced concrete structure with alloyed steel rebar under the chloride environments. The “rebar corrosion” and “rebar/concrete interface characteristic” are regarded as the dual-core problem during the whole research. Firstly, the macro/micro corrosion characteristic of the alloyed steel rebar, including the corrosion rate and the non-uniform corrosion, will be systematically investigated. The developing model of the rebar corrosion and the corrosion evaluating system will be established. Meanwhile, the electrochemical mechanism and the dynamic law of the alloyed steel rebar corrosion will also be revealed. Secondly, the evolution law of the microstructures and stress state of the rebar/concrete interface caused by the dynamic development of the corrosion products will be investigated. Meanwhile, the key control parameters and the threshold values of the interface deterioration will be monitored. And then, the evolution law of the corrosive cracking induced by the interface deterioration will be clarified, and the corrosive-cracking model of the alloyed steel rebar concrete under the contamination of chloride will be established. Based on the above systematic investigation, the anti-corrosion mechanism dominated by the alloying elements of the rebar, as well as the interface deterioration mechanism controlled by the chloride environment, of the alloyed steel rebar concrete will be completely revolved. This study will establish sound theoretical basis for the long-life service of the reinforced concrete structure with alloyed steel rebar under the severe corrosive environment.

本项目瞄准严酷环境下混凝土材料与结构长寿命的迫切要求，针对碳素钢筋耐蚀性不足导致混凝土锈裂这一瓶颈问题，提出以合金钢筋潜在的“高耐蚀性”和“低锈胀率”特征阻抑锈胀延缓锈裂的策略。以氯盐诱导合金钢筋混凝土缓慢锈裂过程为主线，紧扣“钢筋锈蚀”和“钢筋/混凝土界面特征演化”两个核心问题，深入研究合金钢筋锈蚀速率和非均匀锈蚀等宏/微观锈蚀特征，建立其锈蚀发展模型和耐蚀性评价体系，多尺度揭示其腐蚀动力学规律与电化学本质；研究锈蚀产物动态发展引起的合金钢筋/混凝土界面微结构和应力状态演化规律，掌握界面劣化的关键控制参数与阈值，探明界面劣化引起的锈胀裂缝形成与发展规律，构建氯盐诱导合金钢筋混凝土锈裂模型。结合材料学、力学和腐蚀电化学原理，阐明合金元素主导的合金钢筋耐蚀机理，揭示氯盐诱导合金钢筋/混凝土界面劣化机制，为严酷环境下合金钢筋混凝土结构长寿命服役打下坚实的理论基础。

海洋环境氯盐侵蚀诱导钢筋锈蚀引起混凝土开裂是导致钢筋混凝土结构提前失效的主要原因。项目面向海洋混凝土结构长寿命安全服役的迫切需求，研制了具有“高耐蚀性”和“低锈胀率”特征的00Cr10MoV新型合金钢筋，并系统研究了氯盐诱导下合金钢筋锈蚀行为及其钢筋/混凝土界面特征演化机制。项目研究了合金钢筋显微组织特征和宏微观力学性能，多角度地揭示了合金钢筋的高强韧机理；采用浸泡腐蚀、盐雾腐蚀和通电加速锈腐蚀等多种手段，运用腐蚀电化学试验系统研究合金钢筋及其砂浆/混凝土试件的钝化行为和锈蚀行为，全面掌握了氯盐侵蚀条件下合金钢筋耐蚀性，探明了基于复合钝化膜和复相基体组织的合金钢筋耐蚀机理；借助先进的微结构分析测试技术和X-CT断层扫描技术，掌握了合金钢筋的宏微观锈蚀特征、锈蚀产物特征和锈蚀界面特征，探明了合金钢筋/混凝土界面劣化机制；借助数字图像相关技术连续监测合金钢筋/混凝土锈蚀界面劣化引起的锈胀裂缝特征及其演变规律，构建了氯盐诱导合金钢筋混凝土锈裂模型。结合项目研究，以第一作者和通讯作者发表SCI论文8篇，EI论文1篇，合作发表EI论文和中文核心期刊论文各1篇；授权发明专利1件，申请受理（公开）发明专利1件。获教育部科技进步二等奖1项（排名6/15）。培养博士后1名，博士研究生2名，硕士研究生5名，参加国际学术会议3次。