盐冻环境下钢筋混凝土桥面板耐久性寿命研究

发布时间：2018-05-08 09:50

本文选题：桥面板 + 盐冻　；参考：《东北林业大学》2014年硕士论文

【摘要】：钢筋混凝土结构是当今应用最广的结构形式,在西部盐碱地带及北方应用了融雪剂的路桥工程环境中,氯离子侵入混凝土导致钢筋脱钝并发生锈蚀,随着锈蚀的发生与加剧,锈蚀产物体积膨胀导致混凝土保护层胀裂或剥落,造成钢筋混凝土结构发生耐久性破坏。钢筋混凝土桥面板在桥梁各个构件中受到盐冻破坏最严重也最直接,盐冻环境下耐久寿命的预测是钢筋混凝土桥面板耐久性设计、评估和结构维修决策亟需解决的问题。本文在总结前人对钢筋混凝土结构冻融研究工作的基础上,选取了钢筋混凝土桥面板作为研究对象,设计制作了15根梁试件、75块钢筋拉拔试件,其中每种试件包括3个不做处理的对照试件,在构件进行有限次冻融循环后进行相关数据的测定和研究。本文主要工作如下： 1.对12根100mm×100mm×400mm的试件进行300次冻融试验,每25次循环进行一次重量损失与动弹性模量的测定。 2.对72块钢筋拉拔试件进行冻融试验,冻融循环次数包括50次、100次、150次,拉拔试件中粘贴钢筋应变片,待冻融试验结束后进行拉拔试验,测定钢筋与混凝土粘结力的变化、钢筋与混凝土相对滑移等数据。 3.拉拔试验结束后,取试件表层、距表层25cm和钢混结合面处的混凝土做电镜扫描,测定不同深度混凝土氯离子的含量,观察其水化物形貌特征和孔隙结构变化,探究不同冻融次数、不同氯离子浓度、不同层深下氯离子的分布规律和扩散规律。 4.以质量损失、动弹性模量、钢混粘结应力为参数,通过建立基于可靠度理论的钢筋混凝土桥面板耐久性寿命模型,对传统的盐冻后钢筋混凝土桥面板耐久性寿命数学模型进行修正,探究并提出评价桥面板结构耐久性寿命预测的科学、准确的方法。
[Abstract]:Reinforced concrete structure is the most widely used structural form nowadays. In the road and bridge engineering environment where snow melting agent is used in the western saline-alkali land zone and the northern part of the area, chloride ions intruding into concrete lead to the desensitization and corrosion of steel bar, and with the occurrence and aggravation of corrosion, The volume expansion of corrosion products results in the cracking or spalling of concrete cover, which results in durability damage of reinforced concrete structure. The reinforced concrete deck slab is the most seriously damaged and directly damaged by salt freezing in each component of the bridge. The prediction of durability life in salt frozen environment is an urgent problem for durability design evaluation and structural maintenance decision of reinforced concrete bridge deck slab. On the basis of summing up the previous researches on the freeze-thaw of reinforced concrete structures, this paper selects reinforced concrete bridge deck as the research object, and designs and manufactures 15 beams and 75 steel drawing specimens. Each specimen consists of three untreated control specimens. The data are measured and studied after limited freeze-thaw cycles. The main work of this paper is as follows: 1. Three hundred freeze-thaw tests were carried out on 12 100mm 脳 100mm 脳 400mm specimens. The weight loss and dynamic elastic modulus were measured once every 25 cycles. 2. The freeze-thaw test was carried out on 72 steel bar drawing specimens. The number of freeze-thaw cycles included 50 times, 100 times and 150 times. The steel bar strain gauges were pasted in the drawing specimens. After the freezing and thawing tests were finished, the tensile tests were carried out to determine the change of the bond force between steel bars and concrete. Relative slip of steel bar and concrete. 3. After drawing test, the surface layer of the specimen was taken and the concrete from the surface layer of 25cm and steel concrete was scanned by electron microscope. The chloride ion content of concrete with different depth was measured, and the morphology characteristics of hydrates and the changes of pore structure were observed. The distribution and diffusion law of chloride ions in different depth and different concentration of chloride ions were studied. 4. Taking mass loss, dynamic modulus of elasticity and bond stress of steel mixing as parameters, the durability life model of reinforced concrete deck slab based on reliability theory is established. The traditional mathematical model of durability life of reinforced concrete deck slab after salt freezing is revised, and a scientific and accurate method for evaluating durability life prediction of bridge deck structure is put forward.
【学位授予单位】：东北林业大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U448.34;U441

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