橡胶混凝土强度细观机理研究

发布时间：2018-04-14 06:35

本文选题：橡胶混凝土 + 强度机理　；参考：《郑州大学》2017年硕士论文

【摘要】：强度是混凝土结构设计和安全评定的重要指标,橡胶混凝土中由于橡胶材料的引入,强度较普通混凝土有较大程度的降低,严重影响了其在实际工程中的应用。为了有针对性地提高橡胶混凝土的性能,需对橡胶混凝土强度形成的内在机理进行系统深入研究。本文采用细观力学的方法,建立橡胶混凝土强度细观数值计算模型,模拟橡胶混凝土开裂破坏过程,分析其强度形成机理。主要工作内容和结论如下:(1)整理分析了橡胶混凝土主要组分的本构关系及力学性能。在调研了橡胶材料、混凝土界面过渡区等组分研究现状的基础上,整理了关于橡胶的本构关系和力学性能、混凝土界面过渡区的微观结构和本构关系等相关研究成果,为橡胶混凝土细观模型中材料本构关系的确定和细观参数的取值提供了依据。(2)建立了橡胶混凝土细观数值模型。在细观层次上将橡胶混凝土看作由砂浆基体、粗骨料、橡胶颗粒、粗骨料-砂浆界面、橡胶-砂浆界面和初始缺陷组成的多相复合材料,构建了更接近橡胶混凝土真实结构的细观数值结构模型。通过与橡胶混凝土单轴抗压和劈拉试验的宏观试验结果的对比,验证了模型的适用性。(3)模拟了橡胶混凝土开裂破坏过程,研究了各细观组分对其宏观强度的影响规律。分析了砂浆强度、两类界面中初始缺陷含量、橡胶掺量及粒径等因素对混凝土单轴强度的影响;分析结果显示,砂浆强度和橡胶掺量对橡胶混凝土强度影响最大,其次为界面中初始缺陷含量;橡胶粒径对橡胶混凝土强度影响很小。(4)综合细观模拟和宏观试验结果,对橡胶混凝土强度和破坏机理进行了研究。与普通混凝土相比,橡胶混凝土中增加了橡胶-砂浆界面,界面情况更加复杂。橡胶的掺入将更多的孔隙和微裂纹等初始缺陷带入橡胶混凝土,界面内初始缺陷含量随着橡胶掺量的不断增加而增大。采用细观数值模拟的方法,计算结果显示,随着初始缺陷含量单元面积的增加,橡胶混凝土的强度不断降低。
[Abstract]:Strength is an important index of structural design and safety assessment of concrete. Because of the introduction of rubber material, the strength of rubber concrete is lower than that of ordinary concrete, which seriously affects its application in practical engineering.In order to improve the performance of rubber concrete, the inherent mechanism of strength formation of rubber concrete should be studied systematically and deeply.In this paper, the meso-numerical calculation model of rubber concrete strength is established by using the method of micromechanics, and the cracking and failure process of rubber concrete is simulated, and the mechanism of strength formation is analyzed.The main contents and conclusions are as follows: 1) the constitutive relations and mechanical properties of the main components of rubber concrete are analyzed.Based on the investigation of rubber materials, concrete interface transition zone and other components, the related research results about the constitutive relationship and mechanical properties of rubber, the microstructure and constitutive relationship of concrete interface transition zone, and so on, are summarized.A meso-numerical model of rubber concrete is established, which provides a basis for determining the constitutive relation of material and the value of meso-parameters in the meso-model of rubber concrete.At the meso level, rubber concrete is regarded as a multiphase composite composed of mortar matrix, coarse aggregate, rubber particle, coarse aggregate and mortar interface, rubber mortar interface and initial defect.A mesoscopic numerical structure model which is closer to the real structure of rubber concrete is constructed.By comparing with the macroscopic test results of uniaxial compression and splitting tensile tests of rubber concrete, the applicability of the model is verified. The cracking and failure process of rubber concrete is simulated, and the influence of various meso-components on its macroscopic strength is studied.The effects of mortar strength, initial defect content, rubber content and particle size on the uniaxial strength of concrete are analyzed, and the results show that mortar strength and rubber content have the greatest influence on the strength of rubber concrete.Secondly, the initial defect content in the interface and the influence of rubber particle size on the strength of rubber concrete are small. (4) the strength and failure mechanism of rubber concrete are studied by synthesizing the results of meso simulation and macroscopic test.Compared with ordinary concrete, rubber-mortar interface is added in rubber concrete, and the interface is more complex.With the addition of rubber, more initial defects such as pores and microcracks are introduced into rubber concrete, and the initial defect content in the interface increases with the increase of rubber content.The results show that the strength of rubber concrete decreases with the increase of the area of the element with the initial defect content.
【学位授予单位】：郑州大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU528

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