Rebar Detection with Cover Meter and Ultrasonic Pulse Echo Combined with Automated Scanning System

Abstract

A sufficient concrete cover is essential to ensure the durability of reinforced concrete structures. Nondestructive testing methods that can measure the concrete cover are therefore promising tools. As a part of a research project funded by the Florida Department of Transportation, the capabilities and limitations of cover meter measurements in relation to this testing problem were investigated. Researchers designed a reinforced concrete test block on which properties such as rebar depth, size, and spacing and number of reinforcement layers were varied; the effects these variations had on the measurements were studied. The use of an automated testing frame consisting of two scanners that examined the test block from both sides ensured high positioning accuracy and constant quality in data acquisition and made possible the collection of the data along an extremely dense grid. In addition to the cover meter measurements, which referred only to the cover of the layer closest to the surface, ultrasonic pulse echo measurements were conducted, and a synthetic aperture focusing technique was applied to the data to make the rebars become apparent in refined B-scan images.