混凝土裂缝对氯离子侵蚀作用的影响研究

发布时间：2018-04-03 20:36

本文选题：钢筋混凝土　切入点：裂缝　出处：《中南大学》2014年硕士论文

【摘要】：摘要：氯离子侵蚀是影响混凝土结构耐久性的主要因素之一,混凝土裂缝的产生加剧了氯离子的侵入过程,并最终影响整个结构的耐久性,研究裂缝对氯离子侵蚀作用的影响,对准确预测开裂混凝土的耐久性寿命并进而采取相应措施提高其服役寿命具有十分重要的理论和工程实用价值。依托国家自然科学基金项目“混凝土开裂状态对其内部钢筋锈蚀的影响研究(51278495)”,本文以持续荷载开裂状态下的钢筋混凝土板为试验对象,重点研究了氯离子侵蚀下裂缝对混凝土结构渗透性、钢筋锈蚀速率的影响,主要研究工作如下： (1)分析了氯离子在开裂混凝土中的传输机理及氯离子对钢筋锈蚀的影响原理,针对裂缝对氯离子侵蚀下钢筋混凝土结构耐久性影响研究的不足,开展了持续荷载开裂状态下的钢筋混凝土板的氯盐浸泡试验。 (2)对试件各截面的氯离子浓度进行了详细的剖析,分析了水灰比、裂缝宽度及侵蚀时间的变化对混凝土渗透性的影响,得到了氯离子在开裂混凝土内的扩散规律；建立了综合考虑裂缝、水灰比、时间等多种影响因素的氯离子扩散模型,通过工程实例验证,证明本文的扩散模型具有良好的实用性和适用性。 (3)通过分析开裂混凝土横向裂缝区钢筋腐蚀电流密度随时间的变化关系,得到了水灰比、保护层厚度及裂缝宽度等因素对钢筋锈蚀的影响规律；建立了钢筋腐蚀速率试验模型,并对模型进行了验证分析,相关结论可为工程提供参考。
[Abstract]:Abstract: chloride ion erosion is one of the main factors affecting the durability of concrete structures. The occurrence of concrete cracks intensifies the intrusion process of chloride ions and ultimately affects the durability of the whole structure.It is of great theoretical and practical value to accurately predict the durability life of cracked concrete and to take corresponding measures to improve its service life.Based on the National Natural Science Foundation project "Research on the effect of concrete cracking state on internal steel corrosion", this paper takes the reinforced concrete slab under the condition of continuous load cracking as the experimental object.The influence of cracks on the permeability of concrete structure and the corrosion rate of steel bars under chloride ion erosion is studied emphatically. The main research work is as follows:In this paper, the mechanism of chloride ion transport in cracked concrete and the influence of chloride ion on corrosion of steel bar are analyzed, and the shortage of research on the effect of crack on durability of reinforced concrete structure under chloride ion erosion is discussed.The chloride immersion test of reinforced concrete slabs under the condition of continuous load cracking was carried out.The influence of water cement ratio, crack width and erosion time on the permeability of concrete is analyzed in detail, and the diffusion law of chloride ion in cracked concrete is obtained.A chloride diffusion model considering the factors such as crack, water-cement ratio and time is established. It is proved that the diffusion model in this paper has good practicability and applicability.By analyzing the relationship between corrosion current density and corrosion current density of steel bar in transverse crack area of cracked concrete, the influences of water cement ratio, thickness of protective layer and crack width on corrosion rate of steel bar are obtained, and the corrosion rate test model of steel bar is established.The model is verified and analyzed, and the relevant conclusions can be used as a reference for the project.
【学位授予单位】：中南大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU375

【共引文献】