APPLICATION OF AASHO ROAD TEST RESULTS TO DESIGN OF FLEXIBLE PAVEMENTS IN MINNESOTA

Abstract

THIS PAPER REPORTS ON A STUDY OF THE DESIGN OF FLEXIBLE PAVEMENTS IN MINNESOTA APPLYING SOME OF THE CONCEPTS OF THE AASHO ROAD TEST. THE METHOD PRESENTLY USED TO DESIGN FLEXIBLE PAVEMENTS IN MINNESOTA IS DESCRIBED; IT UTILIZES ADT AND HCADT, A DESIGNATION OF SPRING AXLE LOAD, THE AASHO SOIL CLASSIFICATION SYSTEM, AND GRAVEL EQUIVALENT FACTORS. THE DESIGN METHOD WAS STUDIED BY MEASUREMENTS ON 50 TEST SECTIONS ESTABLISHED ON IN-SERVICE HIGHWAYS THROUGHOUT THE STATE. THE PROGRAM OF FIELD PLATE AND BENKELMAN BEAM TESTS AND LABORATORY STRENGTH TESTS ON THE PAVEMENT MATERIAL IS DESCRIBED. AN IMPORTANT ASPECT WAS VARIATION IN STRENGTH THROUGHOUT THE YEAR. THE PERFORMANCE OF THE SECTIONS HAS BEEN STUDIED BY UTILIZING THE ROUGHOMETER IN DETERMINING PSI; TRAFFIC HAS BEEN EVALUATED; PERFORMANCE TRENDS ARE NOTED, AND PREDICTIONS HAVE BEEN MADE. THE AASHO INTERIM GUIDE AND ASPHALT INSTITUTE DESIGN PROCEDURES, WHICH ARE BASED ON THE CONCEPTS OF THE AASHO ROAD TEST, ARE USED AS A BASIS OF COMPARISON FOR THE PERFORMANCE OF THE MINNESOTA TEST SECTIONS. A RELATIONSHIP USING THE SPRING BENKELMAN BEAM DEFLECTION AND PERFORMANCE, ORIGINALLY DEVELOPED AT THE ROAD TEST, IS EXAMINED AND THE MINNESOTA RESULTS THUS FAR ARE STUDIED FOR COMPLIANCE. MODIFICATIONS OF THE PRESENT MINNESOTA FLEXIBLE PAVEMENT DESIGN ARE SUGGESTED ON THE BASIS OF THE OBSERVED PERFORMANCE OF THE TEST SECTIONS TO DATE. /AUTHOR/