As with the previous two symposia, the 32 papers from the June/July, 1999, Seattle symposium present advances in the nondestructive testing of pavements using conventional falling weight deflectometer techniques and other promising techniques such as ground penetrating radar, rolling weight deflecto

The first step in selecting the optimal rehabilitation strategy for any pavement is to identify the cause of the existing defects. In recent years nondestructive technologies such as Falling Weight Deflectometers and Ground Penetrating Radar have been used to evaluate subsurface conditions. However when used independently these technologies are not always adequate for identifying the cause of pavement deterioration. This paper will present the argument for developing an integrated approach to pavement evaluation wherein the high speed GPR survey results can be used to identify homogenous sections, locate potential subsurface defects and estimate layer thicknesses. The GPR then provides critical inputs to both the processing of the FWD data and the interpretation of the results.

In Project 0-4495 an integrated software package called PAVECHECK was developed to merge the Falling Weight Deflectometer (FWD) and Ground Penetrating Radar (GPR) data together with digital video images of surface condition. The new feature in this analysis is that point-specific layer thickness estimates from the GPR can be used within the layer backcalculation process. Most of the features of the existing COLORMAP and MODULUS programs have been incorporated into PAVECHECK. This report provides a user's manual for the new program.

The objective of this project was to render the Falling Weight Deflectometer (FWD) and Ground Penetrating Radar (GPR) road assessment methods accessible to field engineers through a software package with a graphical user interface. The software implements both methods more effectively by integrating the complementary nature of GPR and FWD information. For instance, the use of FWD requires prior knowledge of pavement thickness, which is obtained independently from GPR. 17.

Ground-penetrating radar (GPR) is a rapidly developing field that has seen tremendous progress over the past 15 years. The development of GPR spans aspects of geophysical science, technology, and a wide range of scientific and engineering applications. It is the breadth of applications that has made GPR such a valuable tool in the geophysical consulting and geotechnical engineering industries, has lead to its rapid development, and inspired new areas of research in academia. The topic of GPR has gone from not even being mentioned in geophysical texts ten years ago to being the focus of hundreds of research papers and special issues of journals dedicated to the topic. The explosion of primary literature devoted to GPR technology, theory and applications, has lead to a strong demand for an up-to-date synthesis and overview of this rapidly developing field. Because there are specifics in the utilization of GPR for different applications, a review of the current state of development of the applications along with the fundamental theory is required. This book will provide sufficient detail to allow both practitioners and newcomers to the area of GPR to use it as a handbook and primary research reference. *Review of GPR theory and applications by leaders in the field*Up-to-date information and references*Effective handbook and primary research reference for both experienced practitioners and newcomers