Experimental investigations of damage evolution in concrete during bending by continuous micro-CT scanning

The paper describes experimental investigation results of fracture in notched concrete beams under quasi-static three-point bending. To visualize 3D fracture in concrete under bending, an extended X-ray micro-computed tomography system was used, i.e. the tomography system SkyScan 1173 was connected to the loading machine ISTRON 5569. This combined system enabled to shot images of deforming concrete beams during a continuous deformation process, i.e. without beams' unloading for scanning. The shape, volume, size of cracks and pores were non-destructively measured during deformation. The maximum crack width during continuous micro-CT scanning was higher by about 20-30% than in the beam that was subjected to unloading for scanning.