阻锈剂对海水拌和再生胶砂力学性能和钢筋腐蚀行为的影响研究

针对海水拌和再生骨料混凝土的耐久性问题,对比分析了两种阻锈剂在单掺和复掺下对海水拌和再生胶砂力学性能和钢筋腐蚀行为的影响,并通过X射线衍射(XRD)、压汞(MIP)等测试手段分析其影响机理。结果表明:海水拌和再生胶砂在不掺阻锈剂的情况下前期腐蚀速度较快,7 d后腐蚀速度较慢,逐渐趋于钝化;氨甲基丙醇对海水拌和再生胶砂力学性能和钢筋锈蚀性能起不利影响,主要原因是其抑制了水泥水化进程,增加了孔隙数量;五水偏硅酸钠能使海水拌和再生胶砂中的钢筋发生钝化,具有显著阻锈作用,同时可促进C-S-H的形成,优化孔结构,对海水拌和再生胶砂力学性能影响较小。该试验可对海水拌合再生骨料混凝土耐久性的改善和服役安全性的提升提供参考。

Effects of Corrosion Inhibitors on Mechanical Properties and Corrosion Behavior of Recycled Mortar Mixed with Seawater

In view of the durability of reclaimed aggregate mixed with seawater, effects of corrosion inhibitors on mechanical properties and corrosion behavior of recycled mortar mixed with seawater were analyzed and the mechanism was revealed through microscopic experiments such as X-ray diffraction analysis (XRD) and mercury intrusion (MIP). The results show that recycled mortar mixed with seawater has a fast corrosion speed in the early stage, and then the corrosion speed slows down after 7 d and gradually tends to passivation. In addition, aminomethyl propanol has an adverse effect on mechanical properties of the mortar and accelerates the corrosion of steel bars. The main reason is that aminomethyl propanol inhibits the cement hydration process and increases the number of pores. Sodium metasilicate pentahydrate has a significant rust-inhibiting effect, which is beneficial to promote the passivation of steel bars in recycled mortar mixed with seawater. At the same time, sodium metasilicate pentahydrate is helpful to promote the formation of C-S-H in the mortar and optimizes the pore structure, which has little effect on mechanical properties of recycled mortar mixed with seawater. This research provides reference for the improvement of durability and service safety of recycled concrete mixed with seawater.