Detecting and evaluation of fatigue damage in concrete with industrial computed tomography technology

For effective maintenance of concrete structures, it is necessary to detect and evaluate the increasing fatigue damage. Fatigue loading tests under uniaxial compression was conducted on cylindrical concrete specimens with a diameter of 50 mm and a length of 100 mm. Spatial distribution of fatigue cracks within concrete was observed using industrial computed tomography (ICT) technology, the expanding process was summarized, and the internal fatigue crack ratio of concrete was accurately described. In addition, based on the quantitative description method of the overall distribution of fatigue cracks in concrete, the fatigue damage parameter D was defined which can better reflect the overall crack distribution of concrete fatigue. By comparing with the existing damage parameter in other researches, it can be indicated that the definition in this study can better characterize the evolution process of material fatigue damage of concrete under compression from the overall distribution of fatigue cracks. This method provided an effective opportunity to estimate fatigue damage status of concrete, and promoted the research of concrete fatigue from basic theory. (C) 2019 Elsevier Ltd. All rights reserved.