Analysis of Damage in Specimen Under Cyclic Uniaxial Loading Test by X-Ray CT Method

The X-ray method was applied to evaluate damages, namely deterioration in concrete specimen under cyclic uniaxial loading test. The μ-focus X-ray CT scanner was used in this research. The concrete cylinders with a diameter of 50 mm and a length of 100 mm were prepared as specimen. The cyclic uniaxial loading tests were conducted for the specimen. At that time, the load level at each step of cyclic loading were 60%, 70%, 80% and 90% of the uniaxial compressive strength of specimen. The X-ray CT images of the specimen were taken before and after loading. The 3DMA (3 Dimensional Medial axis Analysis) method was applied to the 3D CT image to estimate porosity and width, length, persistence of cracks. As results, it was shown that the porosity increased with increasing applied cyclic load and that the new micro-cracks occurred with increasing applied cyclic load through analysis of the burn number which indicates the crack width. Consequently, it was concluded that the X-ray CT method is available for evaluating the porosity and the burn number which are parameters of the deterioration estimation of the specimen.