A new nondestructive, noncontact method for thickness measurement is available and can be implemented from a survey vehicle moving at highway speed. The technology incorporates horn antenna radar equipment coupled with customized processing software. This report describes an accuracy evaluation of this technology in which results from 10 Strategic Highway Research Program Long Term Pavement Performance (SHRP-LTPP) asphalt pavement sections in 10 states were compared to core data. The results were evaluated and reported in two steps--blind and calibrated.

The proceedings of June 1993 international symposium held in Atlanta, Georgia, called specifically to develop and standardized evaluation procedures for non-destructive methods of testing pavements. The 29 papers discuss analytical models and techniques, measurement and calculation techniques in the field and laboratory, problems and errors associated with backcalculation methods and design parameters, and testing for other pavement uses. Also includes a history of the quest for a standard and the status of that effort. Reproduced from typescripts. Annotation copyright by Book News, Inc., Portland, OR

This synthesis will be of interest to state Department of Transportation (DOT) geotechnical, bridge, and pavement engineers, engineering geologists, consultants involved with ground penetrating radar (GPR) investigations for state DOTs, and researchers. It describes the current state of the practice of using GPR for evaluating subsurface conditions for transportation facilities. This was accomplished by conducting a literature search and review and an extensive survey of U.S. and Canadian transportation agencies and practitioners, as well as limited international information collection. GPR is a noninvasive nondestructive tool used in transportation applications such as evaluation and characterization of pavement systems, soils, and environmental problems. This report of the Transportation Research Board presents information on the principles, equipment, logistics, applications, and limitations of GPR pertaining to transportation applications. Selected case studies for which ground truth information is available are presented. In addition, an extensive bibliography and glossary are provided as well as appending information about GPR manufacturers from their literature.

The research project objective was to develop an implementation strategy for the use of Ground Penetrating Radar (GPR) technology to address pavement systems and underground utilities. The project was divided into three tasks. Task 1 dealt with a review in the state-of-the-art in technology, relevant applications, and regulations in the use of GPR. Task 2 discussed the effort and results of GPR survey projects on pavements systems and underground utilities that were performed as part of this project in selected locations. Task 3 developed an implementation strategy for NYSDOT for defining and procuring GPR services in addressing problems in pavement systems and mapping & locating underground utilities.