【作者】 刘中辉；

【导师】 施养杭；

【作者基本信息】 华侨大学 ， 结构工程， 2006， 硕士

【摘要】 混凝土结构耐久性是目前国际结构工程学科研究的热点问题。由于人们过去忽视了混凝土结构的耐久性，致使大量的混凝土结构仅仅服役三四十年甚至一二十年就因耐久性失效而提前破坏，造成了巨大的经济损失和不良的社会影响。引起混凝土结构耐久性破坏的因素很多，究其根本，最主要的是钢筋锈蚀。其中，氯离子又是造成钢筋锈蚀的首要原因。因此，研究氯离子侵蚀环境下混凝土结构的耐久性问题有着极其重要的现实意义和深远的历史意义。本文以“国家混凝土规范第6批科研课题[GBKY6001]”和“华侨大学高层人才科研基金[05BS303]”为依托，对氯离子多维侵入混凝土和引起钢筋锈蚀的机理及钢筋初锈时间的确定进行了研究，具体研究内容如下： 1、分析了氯离子引起钢筋锈蚀的机理及氯离子侵入混凝土的机理，详细介绍了影响氯离子侵入速度的内外部影响因素及规律，为混凝土结构的耐久性设计提供科学依据。 2、介绍可靠度的基本原理及计算可靠度的主要方法，首次采用JC法建立氯离子侵入混凝土的一维扩散可靠度模型。经分析与研究发现，与中心点法相比，该模型的计算精度高，对钢筋初锈时间的求解精度要求较高的结构尤为适用。 3、首次应用无条件稳定的交替方向隐格式，建立氯离子侵入混凝土的二维扩散有限差分模型。在步长为任意取值的情况下，该模型可确保计算结果的绝对收敛，主要可应用于计算初始条件和边界条件比较复杂的矩形等截面构件边角处钢筋的初锈时间。经与解析解模型对比发现，该模型计算精度高，应用范围更为广泛，可直接应用于工程实践之中。 4、分析影响氯离子二维扩散的主要因素，即扩散系数、扩散时间、钢筋位置、边界浓度、截面尺寸等。经研究发现，扩散系数和扩散时间既影响氯离子的二维扩散区域大小，又影响其扩散程度，可将这两者定义为一级影响因素；而其他因素仅影响二维扩散程度，不影响扩散区域，可定义为二级影响因素；当截面尺寸大于某一数值后，二级影响因素对氯离子二维扩散几乎没有影响。更多还原

【Abstract】 The durability of reinforced concrete structure is now a concerned problem researched by the international subject of structural engineering. Because The durability of reinforced concrete is ignored by people in the past years,a lot of reinforced concrete structure which is used only thirty to forty years or even ten to twenty years failed before its normal using years due to durability failure,and it results in huge economic loss and bad social impact.There are many factors which can cause reinforced concrete structure durability destruction,but reinforcement corrosion is the uppermost one.Chloride ion is the principal factor causing reinforcement corroding,therefore it is a matter of great significance to research the durability problem of reinforced concrete structure under the circumstances of chloride ion.Based on the background of ’The Six Group Researching Subject of National Concrete Code Project[GBKY600]’ and ’Scientific Research Found of Person with Excellent Ability of Huaqiao University[05BS303]’,this paper researched the mechanism of chloride multiple- dimension erosion、 the mechanism of chloride ion action on steel bar,and the beginning corrosion time of steel bar. Exact researching contents are as follows:1 、 The mechanism of chloride erosion and the mechanism of chloride ion action on steel bar are analyzed.Inner and outer factors having an effect on erosion speed of chloride ion and its impacting law are detailedly introduced,at the same time this paper provided scientific advice for the durability design of reinforced concrete.2、 The structural reliability theory and the primary calculation methods of degree of reliability are introduced. Model of degree of reliability of one-dimension diffusion of chloride ion is set up using JC method for the first time;It is found after analyzing and researching that this model is preciser than the model of degree of reliability set up using the center method, and fit the structure which demanded better solving precision for the beginning corrosion time of steel bar.3 、 A finite difference model of two-dimension diffusion of chloride ion erosion is set up using unconditionally stable alternating direction implicit scheme for the first time.This model can make sure steps are free and calculation result is absolute convergence,and is used mostly to conculate the beginning corrosion time of steel bar in the corner of rectangle section members whose boundary and initial conditions are complex. After comparative analysis of this model and analytical model,it is found that the calculation precision of this model is high and application range is wide.This model can be applied to practice.更多还原