Taiyuan Ligong Daxue xuebao (Nov 2023)
Research on Internal Defects of Self-compacting Concrete Steel Pipe Column by Ultrasonic Detection
Abstract
Purposes This work has been done in order to study the quantitative test of the internal defect and interfacial bond detection of self-compacting concrete steel tube columns has been a hot research topic in the industry. Methods In this paper, ultrasonic non-destructive testing method is used to detect and analyze the defect of C60 self-compacting concrete steel pipe column. The first wave time is used to detect the transmission path of ultrasonic wave, and a method to determine the abnormal value of wave velocity is proposed. The measuring point with velocity less than 4.5 km/s is determined as the abnormal point according to the embedded defect. The location of defects is determined by 3D wave velocity curved surface and defect height curved surface. According to the sound time difference of each measuring point, the defect size is quantitatively analyzed by geometric method. Findings The research shows that the steel pipe wall has little influence on the ultrasonic parameters of inner concrete. The shorter the first wave sound time, the higher the compactness of concrete. When concrete in steel pipe column is defective, the longer the sound time, the smaller the amplitude and the smaller the first wave and adjacent wave amplitudes. The anomalous area of each plane velocity basically corresponds to the actual defect location, the maximum defect size is 233 mm, and the location corresponds to the location of embedded cubic and spherical defects. When the speed of ultrasonic wave is less than 4.0 km/s and the height of defect exceeds 50 mm, it can be preliminarily determined that there are large defects or voids in concrete. The calculated size of defect differs slightly from the actual defect size, which indicates that ultrasonic nondestructive testing technology can be applied in engineering practice.
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