AASHO ROAD TEST EQUATIONS APPLIED TO THE DESIGN OF BITUMINOUS PAVEMENTS IN ILLINOIS

THE ILLINOIS DIVISION OF HIGHWAYS STUDIED THE RESULTS OF THE AASHO ROAD TEST PROJECT AND IS DOING RESEARCH DIRECTED TOWARD DEVELOPING PRACTICAL APPLICATION OF THE FINDINGS. THIS WORK RESULTED IN THE DEVELOPMENT OF TWO INTERIM DESIGN PROCEDURES, ONE FOR BITUMINOUS PAVEMENTS AND THE OTHER FOR PORTLAND CEMENT CONCRETE PAVEMENTS. BACKGROUND INFORMATION AND CONCEPTS USED IN DEVELOPING THE DESIGN PROCEDURES OF BITUMINOUS PAVEMENTS, DESCRIPTION OF THE DEVELOPMENT OF THE PROCEDURE AND APPLICATION DEMONSTRATED ARE PRESENTED. THE PROCEDURE PROVIDES FOR ESTABLISHING THE TYPES AND THICKNESSES OF MATERIALS TO BE USED IN THE VARIOUS LAYERS OF THE PAVEMENT STRUCTURE CONSISTENT WITH THE VOLUME AND COMPOSITION OF TRAFFIC, THE LENGTH OF TIME THE PAVEMENT IS TO SERVE THIS TRAFFIC, THE STRENGTH CHARACTERISTICS OF THE SUBGRADE SOILS AND PAVEMENT MATERIALS AND THE MINIMUM LEVEL OF SERVICE TO BE PROVIDED BY THE PAVEMENT DURING ITS LIFETIME. THE AASHO ROAD TEST FLEXIBLE PAVEMENT PERFORMANCE EQUATION SERVES AS THE BASIS OF THIS DESIGN PROCEDURE.