SOME NOTES ON PAVEMENT STRUCTURAL DESIGN

THE EMPIRICALLY DERIVED DESIGN EQUATION RESULTING FROM THE ANALYSIS OF LOAD TEST DATA OBTAINED BY THE CANADIAN DEPARTMENT OF TRANSPORT ON AIRPORT PAVEMENTS IN CANADA BY MEANS OF PLATE BEARING TESTS, IS REVIEWED AND SHOWN TO BE AN ELASTIC EQUATION, AND IS FOUND TO BE RELATED MATHEMATICALLY TO THE ELASTIC EQUATIONS DEVELOPED BY BURMISTER FOR HIS LAYERED SYSTEM APPROACH TO PAVEMENT DESIGN. ANALYSIS OF THE HYBLA VALLEY LOAD TEST DATA SHOWS THAT FOR ANY GIVEN SIZE OF LOADED AREA, THE PAVEMENT FACTOR VARIES WITH PAVEMENT THICKNESS AND HAS A MINIMUM VALUE AT SOME THICKNESS ROUGHLY BETWEEN THE RADIUS AND THE DIAMETER OF THE LOADED AREA. ON THE BASIS OF HYBLA VALLEY LOAD TEST DATA, THE INFLUENCE OF VARIABLES SUCH AS SIZE OF LOADED AREA , PAVEMENT THICKNESS, AND DEFLECTION, ON VALUES OF THE PAVEMENT ELASTIC MODULUS AND SUBGRADE ELASTIC MODULUS IS INVESTIGATED, AND THE NEED FOR A RAPID, SIMPLE, PRECISE METHOD FOR EVALUATING THE ELASTIC MODULI FOR BOTH DYNAMIC AND STATIC LOADING CONDITIONS IS EMPHASIZED. DATA PRESENTED SUGGEST THAT THE CONVENTIONAL METHOD OF FLEXIBLE PAVEMENT DESIGN, WHICH CALLS FOR GREAT THICKNESSES OF GRANULAR SUBBASE AND BASE COURSE MATERIALS OVER POORER SOILS, TENDS BE WASTEFUL OF THE DIMINISHING AGGREGATE RESOURCES. THE TECHNICAL UTILITY OF THIS SOLUTION TO THE PROBLEM OF ACHIEVING GREATER BEARING CAPACITY IS QUESTIONED AND IT IS SHOWN THAT THE ADDED THICKNESS IS OFTEN WELL DOWN ON THE CURVE OF DIMINISHING RETURNS WITH REGARD TO STRENGTH INCREASE. THE QUALITY OF INFERIOR GRANULAR MATERIALS COULD BE ACHIEVED BY TREATMENT OF THE ENTIRE DEPTH OF PAVEMENT MATERIAL ABOVE THE SUBGRADE TO INCREASE THE ELASTIC MODULUS SO THAT A PAVEMENT STRUCTURE OF MUCH SMALLER THICKNESS WOULD HAVE THE NECESSARY OVERALL STRENGTH. INCREASING THE ELASTIC MODULUS OF THE PAVEMENT COMPONENT REQUIRES UPGRADING THE STRENGTH CHARACTERISTICS OF GRANULAR OR SOIL MATERIALS BY THE APPLICATION OF STABILIZATION PROCEDURES, AND THE INCORPORATION OF BITUMINOUS BINDERS.

Media Info

  • Media Type: Print
  • Features: Appendices; Figures; References; Tables;
  • Pagination: pp 66-141
  • Monograph Title: Flexible pavement design
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00205291
  • Record Type: Publication
  • Files: TRIS, TRB
  • Created Date: Jan 23 1994 12:00AM