Elastic Modulus Of Steel Fiber Reinforced Concrete Based On The Theory Of Asymptotic Homogenization

Steel fiber reinforced concrete, with its outstanding performance, has been widely usedin varies engineering domains. Several factors will do effects on the mechanical propertiesdue to the compositional features of the materials. Elastic modulus is one of the significantparameters of steel fiber reinforced concrete which is necessary for calculation of deformationand crack width. Thus intensive theoretical research on elastic modulus of steel fiberreinforced concrete is of notable importance and will put forward the technical developmentand the practical progress of the materials as well. In this thesis, by applying theory ofasymptotic homogenization and finite element method,3D model of structure cell wasproposed with the assumption of qusiperiodicity distribution of internal structure in steel fiberreinforced concrete. Computational program of homogenization was compiled. Therelationship of mechanical performance and internal structure of steel fiber reinforcedconcrete has been studied. The contents and results are summarized as follows:1. Development, application and research on basic theories of steel fiber reinforcedconcrete were reviewed and summarized;2. Effective modulus of steel fiber reinforced concrete was calculated by utilizing thetheory of asymptotic homogenization. Effects of volume fraction and aspect ratio of steelfiber and the matrix intensity on the elastic modulus of the composites were studied;3. The results show that the modulus of the material increases with the increment ofsteel fiber volume fraction and intensity of the matrix concrete. For a given volume fraction,aspect ratio of steel fiber has little effect on modulus;4. Method of predicting the modulus of fiber reinforced concrete was proposed based onsimulating the experiment with finite element method. By comparing the results with thoseobtained from the theory of asymptotic homogenization, it shows that similar numericalvalues of modulus can be obtained during the corporation period of the steel fiber and theconcrete matrix without consideration the interfacial adhesion, which conformed the validityof the simulation method for the prediction of modulus;5. Transverse and longitudinal effective modulus as well as the Poisson ratio of steelfiber reinforced concrete with concrete matrix of C30and C40were compared by finiteelement method. The results indicate that both effective modulus and Poisson ration exhibitanisotropy. As volume fraction increase, the anisotropy will be more and more pronounced.