Study On The Mechanics Behavior Of The Concrete Through The CT Technique

First of all, the principle of the computed tomography (abbreviation, CT) technique of the concrete is briefly introduced. Meanwhile, the current CT research about the mechanical behaviors of concrete material is also summarized and analyzed; the deficiency of the current research used and the trend are discussed, too. Then, the paper makes use of the latest CT experimental loading apparatus to obtain the CT image under the condition of the uniaxial compression and the stress-strain curve for the sake of collecting and arranging each datum of the CT image. The destruction process of the concrete can be divided into four stages, that is, compression, enlargement, the expansion of the CT crack, and destruction, which are verified through macroscopic analysis of the image data. Furthermore, the spatial distribution of the crack is pictured and measured by virtue of lateral-level theory combined with the application of the support vector machine and image morphology.Additionally, in view of the research method of the damage-fracture evolution theory and the CT datum drawn from the experiment, new index of physical status of the CT image that changed and developed in accordance with the loading process, e.g. related data ofλ-level perfectness,λ-level damage,λ-level perfect field,λ-level damage field,λ1-λ2 interpreted section in concrete CT image is computed and analyzed, base on which the quantitive description of the CT data is realized. The measuring method, the place where the partial damage and crack occur, their amount as well as spatial size of each index and each parameter are further verified.Based on the idea of partition description used in image disposal, the concrete CT images are divided into different areas, that is, the area of aggregates, motor, cracks and gape. After the minimum and maximum of CT number on the whole region defined are traced, the experienced thresholds of the division criteria are confirmed, based on which the aggregate, motor, crack area or gape of CT image in the phase of different stress on the fixed sections are picked up. At the same time the CT information pertains to different subareas is analyzed. By virtue of the frequency, contour, subarea and extremum of CT number, the beginning position of crack is located, the criterion of CT number is determined when the crack appears, the meso-mechanics of damage evolution is studied. Above all, a statistical damage variable is defined; a damage evolutional equation and constitutive equation based on CT number are developed, too. In breif,the disposal and quantitative description method of the experimental datum based on the image measuring is explored in this paper.