核电安全壳混凝土抗冻性研究

发布时间：2018-02-04 01:47

本文关键词： 核电安全壳混凝土冻融循环管道洞口高温剥落物总质量相对动弹性模量　出处：《华中科技大学》2015年硕士论文　论文类型：学位论文

【摘要】：混凝土抗冻性是混凝土结构耐久性评价的重要指标,而核电站安全壳结构往往由于管线穿插等需要在结构中预留一些管道洞口,这些管道洞口处是混凝土整体结构中的受力薄弱区域,其在一定程度上影响了混凝土结构的受力性能和耐久性能。因此,本文模拟核电安全壳混凝土结构的管道洞口和高温条件,对核电安全壳混凝土的抗冻性进行研究具有很重要的理论意义和实际工程价值。本文采用单面盐冻的试验方法,通过预埋钢管模拟核电安全壳上的管道洞口,研究了管道洞口尺寸对混凝土抗冻性能的影响,并且通过单面冻融与单面高温的试验条件模拟出核电安全壳结构在经常性高温工作状态下的冻融过程。试验结果表明:(1)管道洞口的存在降低了混凝土抗压强度,管道洞口面积相对比例增大,混凝土抗压强度随之降低;(2)相对动弹性模量指标在本抗冻性试验中仅起辅助参考作用,有无管道洞口和高温条件对其影响不大;(3)随着冻融循环次数的增加,各组混凝土试件的单位面积剥落物总质量均呈线性增大的趋势,且管道洞口面积相对比例越大,单位面积剥落物总质量越大;(4)处于经常性高温工作状态的混凝土结构,内部高温工作环境能提高结构外表面的抗冻性能。本文以试验得到的相对动弹性模量损失和单位面积剥落物总质量为主要评价指标,建立了洞口尺寸对混凝土抗冻性影响的?(管道洞口面积相对比例)~DF(抗冻耐久性指数)预测模型和高温温度对混凝土抗冻性影响的t(温度)~?(质量损失抗剥落系数)预测模型,研究结果表明此模型拟合得到的理论值和试验值吻合得很好。论文的研究成果对提高核电安全壳混凝土结构的抗冻性有很好的理论意义和工程价值。
[Abstract]:The frost resistance of concrete is an important index to evaluate the durability of concrete structure. However, the containment structure of nuclear power plant often needs to reserve some pipe openings in the structure because of pipeline insertion and so on. The openings of these pipes are the weak areas in the whole concrete structure, which to some extent affect the mechanical performance and durability of the concrete structure. This paper simulates the tunnel opening and high temperature conditions of nuclear power containment concrete structure. It is of great theoretical significance and practical engineering value to study the frost resistance of nuclear power containment concrete. In this paper, single-side salt freezing test method is used to simulate the pipe orifice on nuclear power containment by pre-buried steel pipe. The influence of pipe opening size on the frost resistance of concrete was studied. The freeze-thaw process of nuclear power containment structure under the constant high temperature working condition is simulated by the experimental conditions of one-sided freeze-thaw and single-sided high temperature. The experimental results show that the structure of nuclear power containment is frozen and thawed under constant high temperature. The existence of pipe openings reduces the compressive strength of concrete. The concrete compressive strength decreases with the increase of the relative proportion of the opening area. (2) the relative dynamic modulus of elasticity is only an auxiliary reference in the frost resistance test, and the influence of the opening of the pipe and the high temperature condition on it is not significant; 3) with the increase of freeze-thaw cycle times, the total mass of spalling matter per unit area of each group of concrete specimens increases linearly, and the larger the relative proportion of tunnel entrance area, the larger the total mass of spalling matter per unit area. Concrete structures in constant high temperature working condition. The internal high temperature working environment can improve the frost resistance of the outer surface of the structure. In this paper, the relative dynamic elastic modulus loss and the total mass of the peeling matter per unit area are taken as the main evaluation indexes. The influence of the hole size on the frost resistance of concrete has been established. (the relative ratio of the opening area of the pipeline and the DFI (Frost durability Index) prediction model and the influence of high temperature temperature on the frost resistance of concrete (t (temperature)? (mass loss anti-peeling coefficient) prediction model. The research results show that the theoretical values obtained by the model fit are in good agreement with the experimental values, and the research results in this paper have good theoretical and engineering value for improving the frost resistance of nuclear power containment concrete structures.
【学位授予单位】：华中科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TM623;TU37

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