A RIGID PAVEMENT OVERLAY DESIGN PROCEDURE FOR TEXAS SDHPT

The Texas State Department of Highways and Public Transportation (SDHPT) rigid pavement overlay design procedure was developed by evaluating, improving, modifying, and simplifying a recently developed Federal Highway Administration overlay design method. This overlay design procedure involves fatigue cracking and reflection cracking subsystems. Linear elastic layered theory is the basic model for computing stresses and strains in the pavement system for fatigue computations. The condition and remaining life of the existing pavement are considered in the fatigue cracking analysis, and thickness designs for practically all types of asphaltic concrete and portland cement concrete overlays on rigid pavements can be obtained using this computerized method. The reflection cracking analysis, intended for use with asphaltic concrete overlays, involves the computation of strains in the overlay due to horizontal, thermal, and vertical load-associated movements in the overlay. The final overlay thickness is selected to meet both the fatigue cracking and reflection cracking criteria. The design procedure uses four computer programs for pavement evaluation, overlay thickness design and reflection cracking analysis. A detailed User's Manual intended for use by Texas SDHPT is included in the report. It is recommended that this design procedure be implemented for trial use as soon as possible. This design method is a useful research tool as well as a practical design procedure.