Evaluation Of Concrete Overlays For Bridge Applications PDF Download

Concrete bridge deck overlays have been used in the United States since 1960 to extend the service life of deteriorated concrete bridge decks and improve reliability. Concrete bridge decks with overlays suffer various types of deterioration, so it is necessary to identify and assess the effectiveness of different nondestructive evaluation (NDE) technologies in the laboratory under controlled conditions and in the field under actual conditions. This report provides an overview of seven types of widely used overlays: asphalt with a liquid membrane, asphalt with a fabric membrane, asphalt without a membrane, silica fume-modified concrete, latex-modified concrete (LMC), epoxy polymer concrete, and polyester polymer concrete. This report identifies and ranks available and promising NDE technologies to assess the performance of different types of overlays and concrete bridge decks. This report describes laboratory validation on overlays for nine commonly used NDE technologies. The nine NDE technologies are: sounding, ultrasonic surface waves (USW), impact echo (IE), ultrasonic tomography (UT), impulse response (IR), ground-penetrating radar (GPR), electrical resistivity (ER), half-cell potential (HCP), and infrared thermography (IRT). This report details the results of laboratory tests validating the NDE technologies for the seven different types of overlays. Field validation using the RABITTM bridge deck assessment tool and manual testing equipment was also performed. Results from the study on which this report is based indicated that GPR was the most effective method for detecting defects in underlying concrete specimens through both bonded and debonded overlays; however, GPR could not detect overlay debonding. Results also showed that USW, IE, and UT were effective stress-wave-based methods for detecting defects under bonded overlays but not asphalt overlays. Researchers found that asphalt overlays at low temperatures (i.e., 32°F or below) improved the applicability of