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| FRACTAL COMPARISON RESEARCH OF FRACTURE OF CONCRETE SAMPLES UNDER STATIC AND DYNAMIC UNIAXIAL TENSILE USING CT |
| DANG Faning，FANG Jianyin，DING Weihua |
| (Institute of Geotechnical Engineering，Xi?an University of Technology，Xi?an，Shaanxi 710048，China) |
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Abstract In order to study the static and dynamic strength and crack evolution law of concrete quantitatively by using CT numbers，the portable loading device suitable for CT scanner is used to carry out the static and dynamic uniaxial tensile tests of the cylindrical concrete specimen. Then，the fractal dimension of CT scan section is calculated by using differential box program. And on this basis，the differences of the uniaxial tensile strength feature，failure mechanism and fractal characteristics of crack of the concrete samples under static and dynamic loading were analyzed comparatively from the microscopic level. The results show that the damaged crack of concrete under static uniaxial tensile load grows slowly，the crack surface is rough and twists，and the crack around aggregate follows the weakest interface. The damaged crack of concrete under dynamic uniaxial tensile load grows quickly，the crack surface is flat，and the crack cutting aggregate follows the path which energy released fastest. The static and dynamic CT scan sections have obvious fractal characteristics. The fractal dimension develops with the crack propagation regularly. The CT scan section can well reflect the crack evolution law of the concrete material and can be used as a quantitative parameter of the crack evolution.
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2015, Vol. 34 
