【作者】 朱鹏；

【导师】 屈文俊；

【作者基本信息】 同济大学 ， 结构工程， 2006， 硕士

【摘要】 再碱化应用电化学和电渗原理,在混凝土中钢筋与混凝土外围碳酸钠电解液之间施加一个电场,在直流电的作用下,在阴极钢筋处发生电化学反应产生氢氧根离子,同时碳酸钠电解质向钢筋周围的混凝土渗透,恢复钢筋周围混凝土的高PH值,达到防止钢筋锈蚀的目的。 本文首先对氯离子对混凝土的侵蚀作用进行研究。总结了氯离子扩散试验方法的发展情况,比较各试验方法的不同处,分析不同试验方法的优缺点。同时,对氯离子扩散理论进行研究。介绍了多种氯离子扩散理论模型,展示其理论体系的不断完善,在理论模型中逐渐考虑不同氯离子扩散因素的影响。在此基础上,分析了除盐技术的机理、操作步骤、优势和副作用等。 其次,对再碱化技术展开全面分析。①对于再碱化技术机理的研究,国内外已形成不同的观点,本文比较研究了现存的几种观点,对再碱化技术机理进行全面、深入分析,澄清其中疑问。②总结不同的再碱化技术实验方法,将其归为三类,并进行比较分析;考虑到再碱化技术实验研究中使用的许多技术手段并不为人所熟悉,文中选择介绍分析了较为准确的实验技术,供研究中参考使用。③剖析了控制研究的研究思路,分析其研究进展,揭示其中不足之处,并推荐较完善的控制理论。④分析再碱化技术效果、安全性及其它问题。 最后,对再碱化技术的耐久性进行研究,发现再碱化后混凝土中碳酸钠(常用的再碱化电解液成分)的反向扩散对耐久性有很大影响,并以此为研究对象。对碳酸钠扩散过程进行分析并合理简化,利用菲克第二定律进行推导,建立了碳酸钠浓度发展理论模型,运用此公式可计算再碱化后混凝土中碳酸钠的变化情况。由此理论公式结合理论实验研究进一步得到再碱化耐久性理论等相关理论,根据这些理论可以预测再碱化耐久寿命、计算最佳再碱化厚度和碳酸钠电解液浓度等,解决了再碱化技术研究中的重要问题。并通过算例说明这些理论的运用。另外,设计实验,按照此实验设计进行实验,实验结果可与文中建立理论的计算结果进行比较研究,进而可对各理论进行改进完善。更多还原

【Abstract】 Electrochemical rehabilitation methods are considered as the research objectives in this paper. The electrochemical chloride extraction (ECE) and the electrochemical realkalization (ERA) are studied systematically to promote the application of electrochemical rehabilitation methods.Firstly, the chloride’s corrosion effect on the concrete is studied. Based on the summary of the development of test methods of chloride diffusion, various test methods are compared, and strengths and weaknesses of varied test methods are listed. Then, theories of chloride diffusion are summarized. A list of theoretical equations of chloride diffusion are introduced, and it is demonstrated that the chloride diffusion theory is improved gradually by taking into account varieties of factors, which can affect the chloride diffusion. Based on all these research on the chloride diffusion, the mechanism, operation process, strengths and side- effect of ECE are analyzed.Secondly, the realkalization technique is introduced from diverse research fields. ① Different ideas on the mechanism of the realkalization technique are formed around the world. By comparing all these ideas, the mechanism of the realkalization is analyzed completely and profoundly, and questions about it are answered. ② Experimental methods for realkalization research are summarized and classified into three types. And differences among these methods are analyzed. Considering that many test techniques are rarely used, some reliable test techniques are discovered and introduced for researchers to use. ③ The research route of the control theory is anatomized, the development of research on it is analyzed, defects in the research are disclosed, and a comparatively accurate control theory is recommended. ④ The effectiveness, safety and other problems of the realkalization are analyzed.Finally, the durability of the realkalization is studied, and after the analysis of this problem, it is found that the outward diffusion of sodium carbonate, one of the common used electrolytes, can serve to affect the durability significantly. Therefore, the outward diffusion of sodium carbonate is studied in the thesis. By analyzing andsimplifying the diffusion reasonably, the theoretical model regarding the density development of sodium carbonate in realkalized concrete is established based on Fick’s second law of diffusion. According to this equation, the evolution of sodium carbonate can be computed directly and conveniently, and the theory of the durability longevity of the realkalization and some other relevant theories are deduced based on further theoretical and experimental research. These theories can be used to estimate the durability longevity, and to calculate the realkalization thickness and the density of the electrolyte of the sodium carbonate, which solves some vital problems in the realkalization research. Additionally, some examples are employed to illuminate the application of these theories. -Furthermore, an experiment is designed and the experimental procedure is presented. Experimental results can be used to be compared with calculated results by theories established formerly to improve these theories.更多还原