混凝土双轴压缩强度尺寸效应机理

发布时间：2018-06-19 04:08

本文选题：混凝土 + 双轴压缩强度　；参考：《北京工业大学学报》2017年08期

【摘要】：为了研究混凝土双轴强度尺寸效应产生的机理,考虑混凝土尺寸效应及其宏观力学非线性源于其材料组成的非均质性,结合混凝土细观结构形式,从细观角度将混凝土看作由骨料颗粒、砂浆基质和界面过渡区组成的三相复合材料,建立了尺寸分别为150 mm×150 mm、300 mm×300 mm和600 mm×600 mm的数值混凝土试件.首先通过对150 mm×150 mm方形混凝土试件进行单轴压缩力学特性模拟,采用反演法确定了界面过渡区的力学参数,进而对双轴压缩加载下混凝土的破坏行为及其尺寸效应进行了分析.研究结果表明:1)损伤破坏形式随试件尺寸发生变化,试件最终破坏消耗的断裂能不同是导致混凝土双轴压缩强度产生尺寸效应的主要原因;2)混凝土单、双轴压缩强度均存在明显的尺寸效应行为,并且Bazant尺寸效应律能够较好地描述混凝土在单、双轴压缩加载下的强度尺寸效应.
[Abstract]:In order to study the mechanism of size effect of concrete biaxial strength, considering the heterogeneity of concrete size effect and its macroscopic mechanical nonlinearity from its material composition, combined with concrete mesoscopic structure form. The concrete is regarded as a three-phase composite composed of aggregate particles, mortar matrix and interfacial transition zone. Numerical concrete specimens with the sizes of 150mm 脳 150mm, 300mm 脳 300mm and 600mm 脳 600mm, respectively, are established. Firstly, the uniaxial compression mechanical properties of 150 mm 脳 150 mm square concrete specimens are simulated, and the mechanical parameters of the interface transition zone are determined by the inversion method. Then the failure behavior and size effect of the concrete under biaxial compression loading are analyzed. The results show that the damage failure mode varies with the specimen size, and the fracture energy consumed by the specimen is different, which is the main reason for the size effect of the biaxial compressive strength of concrete. The biaxial compressive strength has obvious size effect behavior, and Bazant size effect law can better describe the strength size effect of concrete under uniaxial and biaxial compression loading.
【作者单位】：北京工业大学城市减灾与防灾防护教育部重点实验室;防灾减灾科技学院;
【基金】：国家自然科学基金资助项目(51421005) 教育部创新团队资助项目(IRT13044)
【分类号】：TU528

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