Correlation of non-destructive pavement test devices

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University of New Brunswick


Currently the New Brunswick Department of Transportation (NBDOT) utilizes the Dynaflect for all non-destructive testing (NDT) of pavement structures. The Dynaflect has been utilized since 1971 to obtain deflection results for use in asphalt overlay design calculations. The deflections obtained with the Dynaflect have to be converted to equivalent Benkelman Beam deflections which are then used to calculate overlay thicknesses. NBDOT is of the opinion that the Dynaflect has some limitations, one of these being that the applied loads do not simulate a moving vehicle either in weight or load application. A new device used for this same type of testing is the Falling-Weight Deflectometer (FWD). This device applies much higher loads which more accurately reflect that of a moving vehicle. This report will investigate if there is a correlation between the Dynaflect and FWD. A correlation between the deflections measured by the devices will allow NBDOT to convert the Dynaflect deflections into equivalent FWD deflections, enabling the use of several overlay thickness software packages designed for the FWD.