FLEXIBLE AND RIGID PAVEMENT OVERLAY DESIGN PROCEDURE

This manual presents design procedures for overlays of both flexible and rigid pavements. The design procedure includes an evaluation of the existing pavement based on nondestructive deflection testing, condition surveys, and materials sampling and testing. Based on this information the pavement is divided into separate design sections and each section is classified according to its condition of cracking. An analysis to determine the required overlay thickness is then made based on the category to which the existing pavement is assigned. The overlay analysis makes extansive use of elastic layered theory and selects the overlay thickness based on the concept of failure by fatigue cracking or rutting. The design procedure uses three computer programs for the pavement evaluation and overlay thickness design. Input guides and illustrative problems for the use of these programs are presented in this report. (FHWA)