ASPHALT CONCRETE PAVEMENT DESIGN-A SUBSYSTEM TO CONSIDER THE FATIGUE MODE OF DISTRESS

IN THIS PAPER A WORKING MODEL IS PRESENTED FOR A SUBSYSTEM TO CONSIDER THE FATIGUE MODE OF DISTRESS FOR ASPHALT CONCRETE PAVEMENTS. THE DESIGN SUBSYSTEM IS DIVIDED INTO THREE GENERAL SECTIONS -- (A) PRELIMINARY DATA ACQUISITION, (B) MATERIALS CHARACTERIZATION, AND (C) ANALYSIS AND EVALUATION. IN DEVELOPING A PARTICULAR DESIGN WITH THIS SUBSYSTEM, USE IS MADE OF TRAFFIC AND WHEEL LOAD DISTRIBUTIONS, ENVIRONMENTAL CONDITIONS BASED ON AVAILABLE WEATHER RECORDS FOR THE VICINITY OF THE PROPOSED DESIGN, MULTILAYER ELASTIC THEORY, RESILIENT RESPONSE OF UNTREATED GRANULAR MATERIALS AND FINE-GRAINED SOILS, STIFFNESS AND FATIGUE CHARACTERISTICS OF THE ASPHALT CONCRETE, AND A CUMULATIVE DAMAGE HYPOTHESIS BASED ON THE SIMPLE LINEAR SUMMATION OF CYCLE RATIOS. TO EXPEDITE THE DESIGN PROCESS, THE MAJORITY OF THE DESIGN COMPUTATIONS HAVE BEEN PROGRAMMED FOR USE WITH A HIGH-SPEED DIGITAL COMPUTER. AN EXAMPLE SHOWS THE USE OF THE DESIGN PROCEDURE FOR A STRUCTURAL PAVEMENT SECTION CONSISTING OF ASPHALT CONCRETE RESTING DIRECTLY ON THE SUBGRADE SOIL. THE DESIGN DEVELOPED IS SHOWN FOR CONVENTIONAL MATERIALS AND TRAFFIC TO RESULT IN A THICKNESS THAT IS QUITE REASONABLE BASED ON COMPARISONS WITH OTHER DESIGN METHODS. THIS PARTICULAR SUBSYSTEM WOULD APPEAR TO HAVE SOME ADVANTAGES, HOWEVER, IN THAT IT CAN BE EXTENDED TO CONSIDER LOADING CONDITIONS AND MATERIAL CHARACTERISTICS FOR WHICH EXPERIENCE IS NOT AVAILABLE. /AUTHOR/