Flexible Pavement Evaluation and Rehabilitation

A method for evaluating a flexible pavement and designing overlays based upon its in-place strength is presented. Strength is determined through a nondestructive dynamic deflection device trade-named Road Rater. Statistical laws are used to determine the characteristic deflection of the pavement, which is then modified to standard conditions. AASHO Road Test data are then used to determine the permissible deflection depending upon the traffic that will be imposed during the overlay design period. Using the modified characteristic deflection and the permissible deflection, the thickness of the overlay required is then computed. The design process is computerized and several practical steps that identify cause and type of failure, which are to be taken in conjunction with the design are advised.