Papers by Author: Wei Xie

Abstract: To discuss the influence of coarse aggregate size, water cement ratio and ages on the concrete compressive strength，the compressive strength tests were carried out by 54 cubic specimens of pebbles concrete in dimensions of 150mm, 18 cubic specimens with dimensions of 200mm and 72 specimens with size of 150mm×150mm×300mm. The results show that the maximum size of coarse aggregate rises with the decrease of the concrete compressive strength; Concrete compressive strength of coarse aggregate size affects more apparently as the ratio of water-cement decrease; with the increasing of age, concrete compressive strength of the aggregate size effect has no significant changes.

Abstract: Concrete is widely used in engineering construction, and studying how to improve the strength of concrete is particularly important. The coarse aggregate is one of the elements in concrete, its property affects the strength of concrete prominently. The effect of coarse aggregate size distribution on the development process of concrete strength was studied, while keeping the constant content of coarse aggregate and altering the size distribution of coarse aggregate and the water to cement ratio. The experimental results show that when the maximum aggregate size is 10mm, 20mm and 30mm respectively, the compressive strength of concrete will be increased, and the flexural strength of concrete will be reduced.

Abstract: A dynamic elastic-plastic microplane constitutive model for concrete based on M2 which is proposed by B.P. Bazant etc., is presented in this paper. The state of each microplane is characterized by normal deviatoric and volumetric strains and shear strain.The strain-stress relations for deviatoric and shear component is described as elastic-plastic model. A new concept: failure strain has been introduced. The stress shall be zero after the microplane stress reaches failure stain level. The reinforced effect of steel fiber on concrete is taken account in this paper. Finally 2 calculation examples have been adopted to verify the rationality and correctness of the proposed module.