| dc.description.abstract | Reinforced Concrete (RC) is a highly non-uniformed complex material composed of cement, sand, aggregate, water, and admixtures. Due to the nature of RC, it is still very difficult to achieve expected accuracy in determining the size of steel bars and locating concrete defects in RC members. This thesis provides several non-destructive testing methods using penetrating γ-rays to project images of steel bars, cracks and holes in RC members on a film. These images are compared to the image of an iron ball whose size is known and hence the size of steel bars and concrete defects can be determined. To further increase the accuracy of inspection, the geometry of the projected images is developed to examine sizes and locations of steel bars, defects and cover depth.
It is known that the key factor of obtaining successful result in (RT) method is the exposure time Radioactive Testing. Therefore, an exposure curve of γrays is generated from testing data and by which the relationship of radioactivity strength, thickness of the reinforced concrete, and exposure time can be precisely established. Through laboratory tests and on-site applications, these methods are proved to effectively increase the accuracy in locating and determining the size of steel bars and defects in RC structures, and the result of inspection can be used in evaluating the safety of construction structures. | en_US |