NONDESTRUCTIVE TESTING OF CONCRETE PAVEMENTS: EQUIPMENT EVALUATION

THE DYNAFLECT IS DESIGNED TO APPLY TO THE PAVEMENT A SINUSOIDAL DYNAMIC LOAD WITH A PEAK-TO-PEAK VALUE OF 1000 LB AT A SINGLE FREQUENCY OF 8 HZ. AN ARRAY OF GEOPHONES ATTACHED TO DEVICE SENSE THE VERTICAL VELOCITY OF THE PAVEMENT, WHICH IS PROCESSED THROUGH A NARROW BAND FILTER AND INTEGRATED ELECTRONICALLY TO OBTAIN DEFLECTION. THE TESTING PROGRAM CONSISTED OF COLLECTION OF DYNAFLECT TEST RESULTS OVER A BROAD RANGE OF AIRFIELD PAVEMENT THICKNESSES, SUBGRADE TYPES AND MODULI, CLIMATIC CONDITIONS AND GEOGRAPHIC LOCALES. THESE DATA WERE ANALYZED, THEN COMPARED WITH THE ACTUAL STRENGTH AND THICKNESS PARAMETERS OF THE VARIOUS PAVEMENT STRUCTURES TO ASSESS THE ACCURACY OF THE DYNAFLECT'S PERFORMANCE. THE RESULTS INDICATE POOR CORRELATION BETWEEN DATA COLLECTION BY THE DYNAFLECT AND ACTUAL PARAMETERIC VALUES. /AUTHOR/