Research Pays Off: Contour Plots Enhance Analysis of Pavement Data Collected with Nondestructive Survey Equipment

Nondestructive test (NDT) methods to collect pavement data—such as the falling weight deflectometer (FWD) or ground-penetrating radar (GPR)—collect data at great speeds and from multiple survey paths; however, the volume of the data also made it complex to analyze. An efficient and comprehensive method was needed to interpret and summarize the increased quantity of data.

In 2008, Florida Department of Transportation (DOT) engineers applied a commercially available contour plotting tool to visualize NDT data from multiple survey paths, improving the identification of pavement areas that required follow-up destructive tests. In a recent research project, Florida DOT pavement engineers developed a methodology to estimate asphalt pavement density with multiple survey paths from GPR.

Analyzing pavement data with contour plots offers an improved and efficient method for evaluating pavement characteristics and selecting the most critical areas for follow-up destructive testing. The contour plot analysis saves time and money by reducing the number of unnecessary destructive tests; improves safety by limiting the exposure of pavement technicians to highway traffic; and reduces disruption to the traveling public.

Florida DOT estimates that integrating NDT equipment and analysis through contour plots can reduce the costs of production testing by as much as 50 percent, because of the decreased need for destructive tests and the reduced duration of lane closures.