Mesoscale Damage Detection and Surface Deterioration of Freeze–Thawed Concrete Cores Using 3D CT Scanning and Roughness Quantification

Abstract

The durability of bridges plays a vital role in their regular operation and transportation, particularly as service life increases. The ability of a bridge to reach its expected service life is closely linked to its durability. In cold regions, the deterioration of bridge concrete durability due to freeze-thaw damage is a common cause of failure, posing a threat to structural safety. In this study, a highway bridge over a sluice that was built 63 years ago was selected for coring and freeze-thaw testing. Two nondestructive testing methods were employed: three-dimensional optical scanning and X-ray computed tomography (X-CT). The former was used to observe and analyze the external surface of the concrete, while the latter was used to analyze its internal structure. The surface morphology was characterized using height, spatial, hybrid parameters, and fractal dimension, and the Abbott–Firestone curve reflected the profile characteristics of the material surface. Moreover, the internal components of concrete were identified and reconstructed in three dimensions based on threshold segmentation, and the changes in internal porosity, pore fractal dimension, and pore size distribution were calculated. Finally, the evolution of bandwidth in the color heat map was analyzed, combining the gray level cooccurrence matrix (GLCM) to reflect the growth of cracks and defects with freeze-thaw cycles.