Performance of NDT Technologies in Detection and Characterization of Reinforced Concrete Deck Deterioration

Abstract

The Strategic Highway Research Program 2 (SHRP 2) supported a study to assess performance of nondestructive testing (NDT) technologies that have potential to identify and characterize deterioration in concrete bridge decks. The study focused on deterioration of the highest importance to transportation agencies: delamination, reinforcement corrosion, concrete degradation, and vertical cracking. Performance of a number of promising NDT technologies was evaluated on a fabricated slab, a section of a removed bridge deck, and an in-service bridge. The technologies included ground penetrating radar, impact echo, infrared thermography, electrical resistivity, half-cell potential, galvanostatic pulse measurement, ultrasonic surface waves, and chain drag/hammer sounding. The technologies were graded and ranked based on five performance measures: accuracy, speed, repeatability, ease of use, and cost. It was determined that no single technology was capable of characterizing all four deterioration types, and that comprehensive condition assessment could be done only by using multiple NDT technologies. Recommendations were made with respect to the selection of the most appropriate technologies to identify specific deterioration types and for their most effective use. The information was summarized in an electronic repository named NDToolbox. The results of the study are applicable to many similar reinforced concrete structural elements, including those used in geotechnical engineering. The scope of the study and the summary of the most important results of the study are presented.