LABORATORY VERSUS NONDESTRUCTIVE TESTING FOR PAVEMENT DESIGN - DISCUSSION

The paper deals with a subject of practical importance in highway engi neering. The authors conclude that good agreement between lab-measured and field-measured moduli of pavement layers and the subgrade should not be expected, and that the moduli from field FWD testing are typica lly of high quality and more appropriate for mechanistic pavement desi gn than lab-measured moduli. However, the authors do not give sufficie nt evidence for the reliability of the FWD testing method. A good matc h of the deflection basin is not enough, because in pavement overlay d esign or structural condition assessment, the layer moduli are often r equired (Ullidtz and Stubstad 1990).