新型高强钢筋在含氯盐混凝土介质中腐蚀与防护的基础研究

The corrosion properties of two new-typed high-strength steel bars, namely HRB500 steel bar and HRBF500 steel bar in chloride contaminated concrete medium are further investigated through laboratory simulation, electrochemical measurements and microscopic analysis. The internal relation between local corrosion behavior and microstructure is established. The corrosion evolution of the interface of steel bar/ concrete medium is revealed. The corrosion mechanism of new-typed high-strength steel bars is illustrated. The essential differences of the corrosion characteristics of the new-typed high-strength steel bars and the common steel bars are proposed. The corrosion behaviors of the macrocells between new-typed high-strength steel bars and traditional normal steel bars which are connected directly are researched by galvanic corrosion test; the corrosion failure feature is investigated and the corresponding mechanism of the galvanic corrosion is revealed. The effect law and mechanism of the typical inhibitors on corrosion properties of new-typed steel bars is studied systematically. The self-healing properties of the corrosion inhibitors for steel bars are also analyzed. The corrosion protection methods with self-healing properties are proposed. This project will improve the corrosion mechanism and protection methods of the new-typed high-strength steel bars. The safety and durability of the concrete structure with new-typed high-strength steel bar will be enhanced. The scientific basis for popularization and application of new-typed high-strength steel bars in aggressive service conditions will be provided. The theories of corrosion and protection for steel bar in concrete structure will be enriched. Therefore, this project has important theoretical significance and precise application.

通过室内模拟、电化学测量和显微分析，深入研究HRB500级和HRBF500级两种新型高强钢筋在含氯盐的混凝土介质中的腐蚀行为，建立钢筋局部腐蚀行为与微观结构的内在联系，揭示钢筋/混凝土介质界面的腐蚀演化进程，阐明新型高强钢筋的腐蚀机理，并给出新型高强钢筋与普通钢筋的腐蚀特性的本质差异。通过电偶腐蚀试验，研究新型高强钢筋与普通钢筋直接接触时的宏电池行为，考察其腐蚀破坏特征，揭示相应的电偶腐蚀机理。深入研究典型钢筋阻锈剂对新型高强钢筋腐蚀性能的影响规律和机制，分析钢筋阻锈剂的自修复性，给出新型高强钢筋具有自愈性的防护方法。本项目可以完善新型高强钢筋的腐蚀机理与防护方法，提高新型高强钢筋混凝土结构的安全性和耐久性，为新型高强钢筋在苛刻服役条件下的推广应用提供科学依据，丰富混凝土中钢筋的腐蚀与防护理论，因而具有重要的理论意义和明确的应用前景。

细晶高强钢筋会产生巨大的经济效益和社会效益，已成为我国的主导受力钢筋，应用范围也在不断推广。然而，细晶高强钢筋因较多的活性晶界使得其腐蚀敏感性明显增大。为了确保苛刻服役环境下工程结构的安全性和耐久性，本课题通过室内模拟、电化学测量和显微分析等方法研究了细晶高强钢筋的腐蚀性能和腐蚀机制。通过动电位循环极化法、交流阻抗谱测量研究了细晶高强钢筋在混凝土模拟液中的腐蚀行为，并与普通钢筋做了对比，结果表明，细晶高强钢筋对氯离子和碳化的腐蚀敏感程度大于普通钢筋的。通过动电位极化、交流阻抗谱测量研究了各种缓蚀剂对细晶高强钢筋腐蚀行为的影响，结果表明，亚硝酸盐、钼酸盐、磷酸盐、钨酸盐、β甘油磷酸盐、癸二酸二异辛酯、烷基-β-氨基乙基咪唑季铵盐、氨基酸型两性表面活性剂等缓蚀剂对细晶高强钢筋在模拟混凝土孔隙液中会表现出不同程度的缓蚀效果，但大部分缓蚀剂的缓蚀效率不如其对普通钢筋的情况。苯并三氮唑、植酸等缓蚀剂对细晶粒高强钢筋没有缓蚀作用，不同其对普通钢筋的情况。通过Mott-Schottky测量研究钢筋表面腐蚀产物膜的半导体特性和载流子密度等，结果表明，在含氯离子的情况下，细晶高强钢筋表面腐蚀产物膜大部分为n型半导体，其致密度不如普通钢筋的，缺陷和载流子密度较大，膜层厚度较低，在较低的电位下膜层就会被击穿。不同缓蚀剂作用下腐蚀产物膜的致密度有所不同，这与显微分析的结果基本一致。.细晶高强钢筋的腐蚀性能不同于普通钢筋，腐蚀敏感性大于普通钢筋。对于工程结构中用到细晶高强钢筋，在进行工程结构服役寿命预测时，不能简单的套用传统普通钢筋的数据，应投入更大的人力物力加强对细晶高强钢筋腐蚀行为的研究。.本项目研究成果共发表学术论文7篇，其中SCI收录4篇，EI收录1篇；培养3名硕士研究生，培养17名本科生。