酸雨环境下氨基醇类阻锈剂的阻锈机理

发布时间：2018-06-08 22:33

本文选题：氨基醇 + 阻锈剂　；参考：《湖南科技大学》2017年硕士论文

【摘要】：钢筋混凝土是目前最常用的建筑结构,由于混凝土孔隙液中的pH接近12.6,使钢筋在高碱性环境下形成钝化膜,不易受侵蚀性离子的破坏。随着工业的发展,酸雨日渐严重,尤其是工业重区,随着钢筋混凝土服役时间的延长,受到较严重的酸雨侵蚀。本文选取能同时抑制腐蚀的阴、阳极过程的氨基醇类阻锈剂,使用单氟磷酸钠阻锈剂做对比,探究氨基醇类阻锈剂在酸雨环境下的阻锈性能,并分析其阻锈机理。本试验通过宏观观察和计算碳钢和钢筋表面锈蚀面积初步判断钢筋阻锈剂的阻锈效果。然后使用微观表征法深入判断阻锈剂的阻锈性能,通过SEM电镜扫描法,测定碳钢表面钝化膜的完整性和致密度、混凝土孔隙的致密性;使用XRD物相分析法,测定碳钢表面和混凝土内的水化产物。最后对碳钢电极和钢筋混凝土电极采用电化学方法,测定其在添加不同阻锈剂的介质条件下的电荷转移电阻、腐蚀溶液电阻等。并与单氟磷酸钠阻锈剂做比较,综合评定氨基醇类阻锈剂在酸雨和氯盐环境下的阻锈性能并探究其阻锈机理。通过试验,本文主要得到了以下结论:1)钢筋混凝土结构中,氨基醇类阻锈剂一方面通过促进钢筋表面形成致密完整的钝化膜,提高钢筋表面活化能,来保护钢筋,另一方面,外涂型阻锈剂通过在混凝土表面形成沉淀,阻碍侵蚀性离子和介质进入混凝土内;内掺型阻锈剂促进混凝土水化,形成凝胶物质,吸附侵蚀性离子和介质,抑制侵蚀性离子和介质侵入混凝土内。从而达到保护钢筋的目的。2)模拟孔隙溶液中,不论氯盐环境还是酸雨条件下,宏观观察、微观表征和电化学阻抗测试均显示氨基醇类阻锈剂阻锈性能优于单氟磷酸钠,其中外涂型阻锈剂效果最佳。相比粉末状的单氟磷酸钠,不论在模拟孔隙溶液还是混凝土结构中,液状的氨基醇类阻锈剂更易扩散且与接触物融合。外涂型阻锈剂效果更优,原因是其扩散和毛细吸收能力强,更易渗入混凝土,不仅在混凝土表面与水泥中的部分物质形成白色沉淀,阻止外界侵蚀性离子的侵入,并且到达钢筋表面后通过特定的官能团或螯合物能与钢筋表面形成更均质稳定的钝化膜;内掺型阻锈剂的XRD物象分析图显示,其C3S衍射峰升高,说明该类阻锈剂能促进混凝土水化,增大其致密度起到阻止侵蚀性离子侵入的作用;到达钢筋表面后两类钢筋阻锈剂在钢筋表面形成保护膜。两类阻锈剂虽均改善了混凝土的致密度,阻止侵蚀性物质的进入,但也抑制了阻锈剂的进入。3)混凝土结构中,氯盐环境下的外涂型阻锈剂性能优于内掺型阻锈剂,而酸雨试剂条件下的内掺型阻锈剂性能优于外涂型阻锈剂,且均优于单氟磷酸钠阻锈剂。相比侵蚀介质单一的氯盐环境,酸雨试剂中较低的pH,复合离子能更快速改变试件所处的环境,加速钢筋脱钝,故钢筋阻锈剂在氯盐环境下能提供更好的阻锈效果。酸雨环境下,内掺型阻锈剂性能更优的原因是硫酸盐与氯盐的耦合作用影响了外涂型阻锈剂的迁移。4)氯盐环境中,模拟混凝土孔隙溶液和混凝土试件中外涂型氨基醇阻锈剂阻锈性能优于内掺型氨基醇阻锈剂。酸雨溶液中模拟混凝土孔隙溶液中外涂型氨基醇阻锈剂阻锈性能优于内掺型氨基醇阻锈剂,但混凝土试件中内掺型氨基醇阻锈剂阻锈性能优于外涂型氨基醇阻锈剂。原因是模拟孔隙溶液中,水剂型阻锈剂可以快速充分的与碳钢电极表面进行反应,外涂型氨基醇阻锈剂对碳钢表面的吸附能力强于内掺型氨基醇阻锈剂的,能更快速形成致密完整的钝化膜,保护钢筋。混凝土试件中,氯盐环境时,外涂型氨基醇阻锈剂通过在混凝土表面形成白色沉淀,能够直接抑制侵蚀性离子侵入混凝土内部,外涂型氨基醇阻锈剂进入混凝土内部后,相比内掺型氨基醇阻锈剂,通过毛细吸收、挥发等方式能更快速到达钢筋表面;酸雨中的氢离子结合混凝土中的碱性物质,降低了混凝土的pH,并且酸雨中的硫酸盐和混凝土中的碱性物质形成沉淀,虽一定程度上抑制侵蚀性物质的进入,但也抑制阻锈剂的进入。模拟孔隙溶液中,酸雨中的硫酸盐和氯离子间存在竞争关系,水化铝酸钙会先与氯离子结合,然后硫酸盐再与剩余的水化铝酸钙反应,所以氯离子能够延缓硫酸盐侵蚀,但降低了溶液pH,恶化了钢筋表面形成钝化膜的条件。
[Abstract]:Reinforced concrete is the most commonly used building structure at present. Because the pH in the concrete pore fluid is close to 12.6, it makes the steel form passivating film under the high alkaline environment. It is not easy to be destroyed by the corrosive ion. With the development of industry, acid rain is becoming more and more serious, especially in industrial heavy area. With the extension of the service time of reinforced concrete, it suffers more severe acid. This paper selects the amino alcohol inhibitor which can simultaneously suppress the corrosion in the negative and anodic process, and compares the rust resistance of the amino alcohol rust inhibitor in the acid rain environment with the contrast of the sodium monotrate rust inhibitor, and analyzes its rust resistance mechanism. This test is used to determine the initial corrosion area of the surface of carbon steel and steel bar by means of macroscopic observation and calculation. In order to determine the resistance of rust inhibitor, the resistance of rust inhibitor is determined by microscopic characterization method. Through SEM scanning electron microscopy, the integrity and density of the passivation film on the surface of carbon steel, the density of the concrete pores are measured, and the hydration products in the surface of carbon steel and the concrete are determined by XRD phase analysis. Finally, carbon steel electrodes and steel are used. Electrochemistry method was used to determine the electric charge transfer resistance and corrosion resistance under the medium of adding different inhibitors. Compared with the sodium monotrate rust inhibitor, the rust resistance of amino alcohol inhibitor in acid rain and chloride environment was evaluated and the mechanism of rust resistance was explored. The following conclusions are obtained: 1) in the reinforced concrete structure, the amino alcohol rust inhibitor can form a compact and complete passivation film on the surface of the steel bar to improve the surface activation energy of the steel bar to protect the steel bar. On the other hand, the coating type corrosion inhibitor can form precipitate on the surface of the concrete, and obstruct the corrosive ions and the medium into the concrete. The internal doping inhibitor promotes the hydration of concrete, forms the gel material, adsorb the erosive ions and media, inhibits the invasive ions and mediators to intruder into the concrete. Thus, the purpose of protecting the reinforced bar is.2). In the simulated pore solution, the macro observation, micro characterization and electrochemical impedance tests show ammonia in both the chlorine and acid rain conditions. The anti rust property of the basic alcohol inhibitor is superior to that of sodium mono phosphate, of which the external coating type inhibitor has the best effect. Compared with the powder like sodium monofluoride, the liquid amino alcohol inhibitor is more easily diffused and fused with the contact matter in the simulated pore solution or the concrete structure. The effect of the coating type inhibitor is better, the reason is its diffusion and capillary. The absorption capacity is strong, and it is easier to infiltrate into the concrete. It not only forms white precipitation on the concrete surface and the cement, prevents the invasion of the external corrosive ions, and can form a more homogeneous and stable passivation film with the surface of the steel bar through the specific functional groups or chelates to the surface of the steel bar; the XRD image analysis diagram of the internal admixture rust inhibitor It shows that the C3S diffraction peak increases, indicating that the rust inhibitor can promote the hydration of concrete and increase its density to prevent the invasion of corrosive ions. After reaching the surface of the steel bar, two kinds of reinforcing rust inhibitor can form a protective film on the surface of the steel bar. The two kind of rust inhibitor improves the density of the coagulant soil and prevents the entry of the erosive substance, but also, it also prevents the entry of the erosive substance. Inhibition of the entry of rust inhibitor into the.3) concrete structure, the performance of the external coated rust inhibitor in the chloride environment is better than the internal admixture inhibitor, while the acid rain reagent is superior to the external coating inhibitor and is better than the sodium monofluoride rust inhibitor. Compared with the single chloride environment of the corrosive medium, the lower pH in the acid rain reagents is complex. In the environment of acid rain, the coupling action of sulphate and chlorine affects the migration of the external coating type corrosion inhibitor.4) in the chloride environment, the simulated concrete hole is simulated in the chloride environment. The resistance to rust in the gap solution and concrete specimen is better than that of the inner admixture amino alcohol inhibitor. In the acid rain solution, the corrosion resistance of the coated amino alcohol inhibitor in the simulated concrete pore solution is superior to the inner admixture amino alcohol inhibitor, but the resistance to rust in the concrete specimen is better than that of the outer coated ammonia. The reason is that the water inhibitor can react quickly and fully to the surface of carbon steel electrode in the simulated pore solution. The adsorption capacity of the coated amino alcohol inhibitor on carbon steel surface is better than that of the inner admixture amino alcohol inhibitor. It can form a compact and complete passivation film more quickly and protect the steel. In the environment, the outer coated amino alcohol inhibitor can form white precipitation on the surface of the concrete, which can directly inhibit the invasion of the corrosive ions into the concrete, and the outer coated amino alcohol rust inhibitor enters the concrete. Compared with the inner admixture amino alcohol inhibitor, it can reach the steel surface more quickly through the capillary absorption and volatilization, and the hydrogen in acid rain The alkaline substance in the ion combined with concrete reduces the pH of the concrete, and the sulfate and the alkaline substance in the acid rain forms precipitation. Although it inhibits the entry of the corrosive substance to a certain extent, it also inhibits the entry of the rust inhibitor. In the simulated pore solution, there is a competitive relationship between the sulfate and the chloride ions in the acid rain, and the hydration is hydrated. Calcium aluminate combined with chloride ion first, and then sulfate reacts with the remaining hydrated calcium aluminate, so the chloride ion can delay sulfate erosion, but reduce the solution pH and deteriorate the condition of the formation of passivation film on the surface of the steel bar.
【学位授予单位】：湖南科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU528.042.6

【参考文献】