氯盐侵蚀条件下混凝土受压疲劳剩余强度试验研究

发布时间：2018-03-28 21:07

本文选题：氯盐侵蚀　切入点：混凝土疲劳　出处：《长沙理工大学》2015年硕士论文

【摘要】：混凝土桥梁结构中,某些构件,长期遭受高应力循环荷载作用,极易导致疲劳损伤甚至破坏;除了疲劳,混凝土桥梁长期在腐蚀环境服役,会缩短使用寿命。混凝土桥梁处于腐蚀环境和循环荷载的复合作用下,桥梁结构的服役寿命会大幅缩短。因此,对在腐蚀条件和循环荷载复合作用下混凝土疲劳性能进行研究,具有重要的理论意义和工程价值。由于混凝土疲劳性能劣化主要表征为混凝土剩余强度的衰减,因此,本文着重开展了氯盐侵蚀条件下混凝土受压疲劳剩余强度试验研究,主要研究内容如下:(1)选取浓度为10%的NaCl溶液对63个混凝土棱柱体试件进行了侵蚀,观察混凝土试件表面形态的变化,对混凝土试件进行静载破坏试验,发现氯盐侵蚀后混凝土试件的破坏形态同未侵蚀混凝土试件存在区别;对试件进行受压疲劳寿命试验,比较氯盐侵蚀混凝土试件和未侵蚀混凝土试件在相同应力水平下疲劳寿命的变化规律。(2)对126个未侵蚀和氯盐侵蚀的混凝土棱柱体试件进行了静载受压试验、疲劳寿命试验和受压疲劳剩余强度试验,分析发现:混凝土剩余强度和疲劳寿命存在比较大的随机性和离散性,有必要引入概率统计方法和可靠度理论对其进行统计分析。(3)推导了利用小样本试验数据对三种概率分布模型的参数进行回归的方法,利用混凝土试件受压疲劳寿命试验的数据,建立了不同应力水平下混凝土受压疲劳寿命的概率分布模型,在此基础上开展了疲劳可靠度的算例分析。(4)利用未侵蚀混凝土和氯盐侵蚀混凝土试件初始受压强度和剩余强度试验数据,建立了不同应力水平下混凝土初始受压强度和剩余强度的概率分布模型,结合混凝土剩余强度衰减模型得到混凝土的P-R-N曲线,对不同应力水平经过不同疲劳加载次数后混凝土的剩余受压强度进行预测,并给出了相应的可靠度。
[Abstract]:Some concrete bridge structure, and long suffering high stress cyclic loading, can easily lead to fatigue damage or even failure; in addition to fatigue, concrete bridge long service in the corrosive environment, will shorten the service life of concrete bridges. In a corrosive environment and composite under cyclic loading, the bridge structure will greatly shorten the service life of it. In the condition of corrosion, and cyclic loading under fatigue performance of concrete is studied, which has important theoretical significance and engineering value. Due to the fatigue performance of concrete deterioration is represented by the attenuation of residual strength of concrete mixing, therefore, this paper focuses on the chloride erosion condition test on fatigue residual strength of concrete in compression, the main research the contents are as follows: (1) selecting concentration were eroded into 10% NaCl solution of 63 concrete prism specimens, observe the concrete specimen surface morphology The change of concrete specimens of static loading test, found the Chloride Erosion of concrete after the failure form of specimens with no erosion of concrete specimens are different; for compressive fatigue life test of the specimen, comparison of Chloride Erosion of concrete specimens and concrete specimens without erosion of fatigue life at the same stress level next. (2) of 126 concrete prism without erosion and chloride corrosion specimens of static compression test, fatigue test and analysis showed that the compressive fatigue residual strength test, concrete residual strength and fatigue life of the relatively large randomness and discreteness, it is necessary to introduce the method of probability and statistics the reliability theory and its statistical analysis. (3) using the method of using small sample test data of three kinds of probability distribution model parameter regression, the concrete compressive fatigue life test The data, set up different probability distribution model of fatigue life of concrete compressive stress level, carried out on the basis of examples analysis of fatigue reliability. (4) the erosion of Chloride Erosion of concrete and concrete specimen with initial compressive strength and residual strength test data, establishes different probability distribution model of initial compressive strength the residual strength of concrete and the stress level, P-R-N curve of concrete attenuation model combined with the residual strength of concrete, the residual compressive strength of different stress level after different fatigue cycles of concrete for prediction, and gives the corresponding reliability.

【学位授予单位】：长沙理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U444

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