NDT METHODS FOR THE IN-SITU EVALUATION OF PAVEMENTS IN THE USA - A REVIEW

In this paper, the non-destructive condition evaluation of both 'flexi ble' and 'rigid' pavement systems is discussed. The objective is to de scribe non-destructive test method(s) for the in-situ, or in-place, ev aluation of individual layers within rigid and flexible pavements. Suc h tests are: the static tests, steady-state dynamic tests, impact resp onse tests, electromagnetic tests, and the wave propagation tests, inc luding the ultrasonic tests, and impact testing. The characteristic th at is exploited is the elastic response of materials within individual pavement layers. It is from these responses that properties, such as strength, deformation, load-carrying capacity, and locations of cracks and flaws of the overall pavement system are inferred. This work aims comprehensively at new, old, and rehabilitated pavement systems. In a ll of these cases, the in-site properties of layers within the pavemen t system are of interest; specification compliance determination, mate rial condition monitoring, or rehabilitation effectiveness determinati on may follow from such knowledge.