Research On Ultrasonic CT Technology To Detect Concrete Medium Hidden Danger

Concrete structure due to improper construction and external force, influence and properties of building materials, the hidden trouble caused by the internal structure of the medium. Medium hidden in concrete structure are mainly cellular voids, cracks and local density. Because of these shortcomings, the concrete structure is incomplete, resulting in the tensile strength and the compressive strength and durability seriously reduce. Hence the need for rapid detection of concrete member in the construction site, is important to ensure the safety of project construction. The current concrete nondestructive testing methods are mainly the rebound method, impact echo method and radar method. These methods have their own drawbacks in the detection process, restricted to the case detection of concrete surface quality, cannot reflect the internal situation, concrete medium instrument more expensive and subject to greater impact on site detection of steel bar, not good for medium resolution scale expansion and the hidden trouble of smaller lower. Ultrasonic detection method can solve these problems effectively, such method has features of high penetration, strong resolution, detection equipment is simple, easy operation, so the detection cost and later data inversion effect than the other method has a great advantage.This paper first made a numerical simulation of a known model. Numerical simulation based on the conclusion, extract the relevant wave field snapshot, preliminary study on ultrasonic propagation in concrete structures. Can be derived from the wave field snapshot, ultrasonic showed obvious differences in concrete medium dissemination of different geological hazard in settings. Secondly, through the numerical simulation to study the effect of ultrasonic observation system of CT imaging resolution, in a basis set of similar numerical simulation model, the arrangement of different observation system, and obtained the best observation system for nondestructive testing of concrete is compared with the CT diagram, studies that measured stage try using a variety of observation system of mutual comparison, mutual confirm the conclusion. In this paper, a numerical study of the sandwich, do empty defect ultrasonic CT probe in concrete, ultrasonic CT diagram obtained the good convergence, more clearly reflect the position and size of abnormal area. The numerical simulation method and physical model test, finally the application of combining, explain each other mutual guidance, the results show that the ultrasonic CT has good resolution in the measurement stage feasibility and high.At the same time, the paper also points out the direction of research is insufficient to detect existing and future nondestructive ultrasonic CT in concrete, physical model is done in this paper, the small size, less abnormal types and the set, although the detection effect is very good but not representative. In actual engineering, concrete structure is complex, and the larger size, the actual effect of detection remains to be further experimental research.