USE OF ROAD TEST FINDINGS BY AASHO DESIGN COMMITTEE

THE DEVELOPMENT IS PRESENTED OF A DESIGN PROCEDURE FOR FLEXIBLE PAVEMENT STRUCTURES AND FOR RIGID PAVEMENT DESIGN PROCEDURE. THE PAVEMENT SERVICEABILITY-PERFORMANCE CONCEPT, USED TO ANALYZE ROAD TEST DATA, IS ACCEPTED AS THE BASIS OF THE DESIGN PROCEDURES. THE GENERAL AASHO ROAD TEST EQUATION IS PRESENTED AND DEFINED. DESIGN CHARTS DEVELOPED FROM THE EQUATION ARE PRESENTED. ASSUMPTIONS MADE ARE REVIEWED TO OBTAIN DESIGN CHARGE APPLICABLE TO A WIDE VARIETY OF SOIL TYPES, TRAFFIC LOADINGS, AND ENVIRONMENTAL CONDITIONS. A TABLE OF COEFFICIENTS FOR THE TYPES OF SURFACE COURSE, BASE COURSE AND SUBBASE ARE PRESENTED IN THE APPENDIX. IN DEVELOPING THE RIGID PAVEMENT DESIGN PROCEDURE, THE FIXED FACTORS EXPRESSED IN THE ROAD TEST EQUATION INCLUDE: (1) MODULUS OF ELASTICITY OF CONCRETE, (2) MODULUS OF RUPTURE OF CONCRETE, (3) MODULUS OF SUBGRADE REACTION, (4) ENVIRONMENTAL CONDITIONS, (5) LIFE SPAN, AND (6) LOAD TRANSFER CHARACTERISTICS. THE SPANGLER EQUATION WAS USED FOR CORNER LOAD STRESSES. NECESSARY COMPUTATIONS ARE PRESENTED FOR: TRAFFIC LOAD APPLICATIONS, WORKING STRESS IN CONCRETE, AND MODULUS OF SUBGRADE REACTION.