EVALUATION AND COMPARISON OF VARIOUS NDT DEVICES IN SIDE-BY-SIDE TESTING ON INDIANA HIGHWAYS. SIXTH INTERNATIONAL CONFERENCE, STRUCTURAL DESIGN OF ASPHALT PAVEMENTS, VOLUME I, PROCEEDINGS, UNIVERSITY OF MICHIGAN, JULY 13-17, 1987, ANN ARBOR, MICHIGAN

As part of a research program designed to provide an overlay design procedure for pavements in Indiana, four Nondestructive Deflection Testing (NDT) devices were compared side-by-side on 73 pavement sections in Indiana. The devices were the Dynaflect, the Road Rater 400, the Road Rater 2000, and the Dynatest Falling Weight Deflectometer (FWD). The 73 sections represent overlaid flexible pavements and both overlaid and non-overlaid JRC pavements. Brief descriptions of activities performed prior to field testing - including data base development, statistical experiment design, and test section selection - are presented, as are preliminary findings from the first of two planned test sequences. Comparisons of the deflection basins and the deflection variations within pavement test sections are made. Equations are presented correlating deflections from the FWD with deflections from the other three devices. Finally, variables are calculated from the deflections and are used as indicators of relative pavement strength characteristics. These indicators are analyzed to predict which of the NDT devices offer the most usable deflection data for investigating pavement structural properties.