Use of ground-penetrating radar data for rehabilitation of composite pavements on high-volume roads

Applications of ground-penetrating radar(GPR) to composite pavements were studied on sections of Interstate highway: I-495 near New York City, I-95 in New Haven, and I-90 in Chicago. The sections, which ranged in length from 4 to 15 mi, needed to be evaluated for asphalt thickness and condition of the underlying concrete in order to plan and carry out rehabilitation and reconstruction programs. Given the high traffic volumes on these roads, lane closures to allow for direct pavement evaluation were unacceptable, and GPR was chosen as the data collection method. The GPR data were collected at normal driving speeds without interference to traffic and were coordinated with mileposts and other structures to ensure ground control for location referencing. The data were then analyzed to produce graphical plots and tabular spreadsheets of asphalt thickness. Contour plots were also produced showing locations of likely deterioration in the underlying concrete. The GPR thickness results were evaluated for reliabilily through correlation with data from core samples. The results of each survey were used as input in planning and scoping the subsequent rehabilitation work. The project objectives, equipment used, data analysis methodology, results obtained, use of the GPR data, and correlations with available core data are described.