Comparative evaluation of nondestructive devices for measuring pavement thickness in the field

Estimating pavement surface thicknesses without requiring large footprint equipment or pavement repairs is critical for the structural evaluation of airfield pavement. A research team from the U.S. Army Engineer Research and Development Center conducted an evaluation of eleven nondestructive technologies, including eight ground penetrating radar (GPR) devices and three wave propagation technologies, on twenty-one hot-mix asphalt concrete (AC) and nineteen portland cement concrete (PCC) test locations with varying pavement thicknesses. The different technologies were used to estimate pavement thickness over predetermined test points. For each pavement structure, a core was extracted from one of the test points to provide calibration data of each testing device for data refinement. The accuracy of each technology was quantified by calculating the absolute difference between the actual core measurement and the estimated thickness measurement. The results from the devices tested led to the conclusion that separate devices are required on AC and PCC for optimal performance. The ultrasonic tomography and impact echo devices worked best on PCC surfaces, and the 1 GHz horn antenna GPR devices performed best on AC surfaces. The side-by-side testing demonstrated the capabilities of the technologies on varying pavement structures without discrepancies that would likely occur when comparing one set of results to those from a different study.