無電鍍鎳鋼筋應用於混凝土中腐蝕行為之初步研究

Preliminary Study of Corrosion-related Behaviors of Concrete Using Electroless Nickel-Plated Steel

無電鍍鎳係化學鍍方法之一種，其鍍膜厚度極薄且其表面硬度高、耐磨、耐蝕性佳，同時兼具焊接性良好等特質，可能適合應用於營建產業鋼筋表面之防蝕處理，而目前仍缺乏相關之研究，在提升材料品質增加實質經濟效益方面，值得深入加以探討。本研究以一般營建用鋼筋為底材，表面施以無電鍍鎳鍍層被覆形成防蝕鍍層，取代傳統一般鋼筋，製作三種不同細骨材含量（含海砂、部分海砂及河砂）之鋼筋混凝土試體，以海水潮間帶之養生池長時間浸泡，同時另一批試體置於台中港區自然環境中，測試不同齡期下混凝土試體處於高氯離子及濱海惡劣環境下鋼筋混凝土之腐蝕行為，另以凍融循環加速試驗測試試體之抗凍融環境能力。試驗結果在防蝕性能方面，由鋼筋拉拔試驗後之鋼筋巨觀檢視中可知，在混凝土的保護下，無電鍍鎳鋼筋具有良好之防蝕性能。在鋼筋握裹力測試方面，無電鍍鎳鋼筋與一般鋼筋之握裹強度差異並不大，顯示鋼筋握裹強度未受鍍膜厚度及其性質之影響。

Electroless Nickel-Plated has been known as one of the chemical electroplates. It’s featured by producing the thin film with remarkable surface hardness, wear resistance, corrosion resistance as well as good adhesion which make it a very promising method of surface coating on steel used for construction. However, the studies for this Electroless Nickel-Plated is still very limited and not yet widely explored. Accordingly, to further improve the process as to increase the economic benefits of its applications will be remained a critical subject to get studied. In this paper, we used Electroless Nickel-Plated steel to replace the conventional steel and embedded in three kinds of reinforced concrete specimens (ie: 100% sea sand; partial sea sand and 100% river sand) and immersed in the pool emulated for the environment of sea shore curing pond for long time. At the same time, we put another set of concrete specimens outdoor inside Tai-Chung Harbor as to test the corrosion resistance under rich chorine environment near by the sea shore. Besides, we also performed the freeze-thaw cycling test in order to test the specimen’s capability of resisting the freeze-thaw conditions. The steel bond stress test showed the excellent corrosion resistance for Electroless Nickel-Plated steel embedded in concrete specimen. And the other steel bond stress test revealed Electroless Nickel-Plated steel has similar performance with the conventional one which means the electroplating has no significant impact on steel bond stress.