Three-Dimensional Measurement of Fire-Damaged Concrete Crack Development Using X-Ray CT Images

This study focuses on the measurement of concrete cracks in three dimensions (3D) using the particle swarm optimization-based projection algorithm, OpenCV technique, and X-ray computerized tomography (CT) images. The primary objective is to visualize the development of cracks in fire-damaged concrete. The data for X-ray CT imaging were collected, consisting of 3,011 CT images obtained from damaged specimens. The sampling criteria employed ensured a convenient sampling process with a 95% confidence level and 5% limits of errors in the 50-50 category. The results reveal that the undamaged specimens exhibited an average of 406 smaller-sized pores, whereas the fire-damaged specimens, which were subjected to a temperature of 900°C for 1 h, displayed a significant increase in the number of pores and cracks. The proposed method successfully enables the plotting of 3D measurements of concrete crack development. This achievement has practical implications for practitioners, as it allows for (1) visualizing crack development as an initial step toward analyzing deterioration patterns in concrete, and (2) conducting an analysis of concrete failure in structures following fire scenario simulations. Overall, the findings of this study contribute to a better understanding of concrete crack development and offer valuable insights for practitioners in the field.