Numerical Test And Research On Affection Of Microscopic Constituent To Macroscopic Property Of Concrete And Granite

Concrete and granite are two kinds of heterogeneous material that are widely used in many engineering including structural engineering. Therefore, the investigation on their mechanical properties and fracture process is of a vital importance to mining engineering, underground engineering and engineering. The classic macroscopic mechanical models, which characterize the concrete and granite as continuums at macroscopic level and consider the test results of laboratory scale specimen as the mechanical properties of the material, could analyze the mechanical response of structures with greater size. In reality, the test results of laboratory that are generally called physical and mechanical parameters of material are average responses of a heterogeneous specimen with a certain size. This kind of homogenization is very important to the investigation of concrete structures and numerical analysis of engineering. But it is difficult to use these models to study the complete failure process caused by the initiation, propagation and coalescence of cracks when subjected external loading. At present, international investigations on the mechanical properties of concrete are beginning to transfer from the classic macroscopic mechanical level to a minor level, i.e. microscopic level, and a lot of microscopic mechanical models had been proposed. But these models are not perfect to some degree. In China, these kinds of research are very few.The textual research contents are as follows with main conclusion:(l)The numerical simulation models of the concrete and granite have been built up, and the tendency of the macroscopic strength has been analyzed, which is influenced by the variety of microscopic components.(2) The influence of the variety of â…  and â…¡ to the macroscopic strength of concrete is important. The tendency of variety, which is received by numerical simulation, is fit the results of experiments well. The strength of concrete is the highest when the ratio of â…  and â…¡ is 4:6.(3)Though the variety of the biotite content in granite is not very important to the influence of macroscopic peak strength of granite, from the microscopic view, a range still a demand attractor that it affect, the peak strength of granite is the highest when the biotite content is about 5%.