Study on concrete in macro-and meso-scale mechanical properties based on homogenization theory
Received:August 18, 2007  
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DOI:10.7511/jslx20096019
KeyWord:concrete  meso-mechanics  homogenization method  asymptotic expansion  random aggregate model
     
AuthorInstitution
唐欣薇 清华大学 水利水电工程系 水沙科学与水利水电工程国家重点实验室,北京
张楚汉 清华大学 水利水电工程系 水沙科学与水利水电工程国家重点实验室,北京
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Abstract:
      In this paper, concrete is taken as a type of three-component composite material composed of mortar matrix, aggregates and interfaces on the meso-scale. Based on the homogenization theory and finite element method, the equivalent macro-elastic constitutive relationship of concrete is analyzed. Through the use of asymptotic expansion of the displacement and the homogenization theory, the FEM equilibrium equations in multi-scale are established. In this analysis, the influence of unit cell size on the elastic properties in macro-scale is studied and the minimum ratio of unit cell size to the maximum aggregate diameter has been obtained, i.e. 5-10 times of the maximum aggregate diameter. Finally, comparison analysis of the macroscopic and the mesoscopic simulation of a 3-Point concrete beam are presented. It is concluded that the macroscopic characteristics of the concrete can be predicted with good accuracy by the presented method. It is also observed that the stress distribution appears a gradual and smooth variation on the macro-scale while a local abrupt change on the meso-scale due to the interaction between mortar matrix and aggregates.