Corrodibility and Adherence of Reinforced Concrete Rebars Electroplated with Zinc and Zinc-Nickel Alloys

Reinforced concrete is the main structural material used in the world in the construction of bridges, roads and commercial and residential buildings. One effective method for preventing corrosion of steel reinforcement is the application of galvanic coatings to the reinforcement itself. The present study evaluated the performance of three groups of reinforcing steel bars (black steel, used as a reference and rebars electroplated with Zinc and Zinc-Nickel alloys) to corrosion and adherence to the concrete matrix. For the analysis of corrosion, the specimens were subjected to two different accelerated corrosion tests: salt spray exposure and wet and dry semi-cycles. The corrosion potential was measured for the qualitative monitoring of the corrosion process and the corrosion rate was estimated. In order to evaluate the steel-concrete adherence, the pullout test was used, in accordance with RILEM-CEB-FIP. The results showed that Zinc and Zinc-Nickel coatings increased the durability of the reinforcing bars and the accelerated corrosion test of wetting and drying cycles proved to be more aggressive compared to the salt spray method to evaluate the corrosion process in the reinforced concrete specimens. Additionally, galvanized reinforcement reduced adherence to the concrete matrix.

钢筋混凝土（Reinforced Concrete）是全球桥梁、道路以及商业与民用建筑施工中应用的主要结构材料。防止钢筋锈蚀的有效方法之一，是在钢筋本体表面施加电偶防护涂层（galvanic coatings）。本研究针对三类钢筋开展了腐蚀性能与混凝土基体黏结性能的评价试验：分别为作为参照组的黑钢裸钢筋、电镀锌钢筋以及电镀锌镍合金钢筋。在腐蚀性能分析环节，试样被施以两种不同的加速腐蚀试验：盐雾暴露试验与干湿半循环试验；通过测试腐蚀电位实现腐蚀过程的定性监测，并估算了腐蚀速率。为评价钢筋与混凝土的黏结性能，本研究依据RILEM-CEB-FIP标准开展了拉拔试验。试验结果表明，锌涂层与锌镍合金涂层可提升钢筋的耐久性能，且干湿循环加速腐蚀试验相较于盐雾试验法，对钢筋混凝土试样的腐蚀过程更具侵蚀性。此外，镀锌钢筋会降低其与混凝土基体的黏结强度。