COMPARATIVE STUDY OF SELECTED NONDESTRUCTIVE TESTING DEVICES

An extensive program of flexible-pavement nondestructive testing (NDT) was conducted by the Illinois Department of Transportation (IDOT) in cooperation with the University of Illinois. Different (mostly in-service) pavements were tested. Conventional granular base and stabilized base material sections were studied. NDT devices used were the IDOT road rater model 2008, the Benkelman beam, and the falling-weight deflectometer. An accelerometer was used to measure surface pavement deflections under moving trucks. The main findings of the comparative NDT program are reported. Deflection-basin parameters for structural pavement evaluation are defined. Correlations and comparisons between the different devices are presented. Overall, the falling-weight deflectometer is the best NDT device for simulating pavement response under moving wheel loads. The road rater, because of its harmonic loading without rest periods and the static preload, induces pavement deflections lower than those achieved with the falling-weight deflectometer and moving wheel loads. Finally, the quasistatic loading in Benkelman beam measurements induces the highest pavement deflections. (Author)