FUNDEMENTAL PROPERTIES RELATIVE TO BEHAVIOR UNDER LOAD

This paper which describes the design of bases and subbases for flexible pavements, briefly reviews the intended functions of bases and subbases and discusses in detail the basic pavement behavior and methods of measuring stability. The difficulty involved in attempting to isolate the effect of multiple variables is pointed out, and simplified treatment is presented of the complex problem of defining the functions of the various pavement layers in providing protection against cracking, rutting and shear deformation without relying too heavily on slab action, which may be "initially approached" by stiffer bases. The concept of thickness equivalency based on fixed, empirically derived strength coefficient for broad classes of materials is cited as fallacions. Capacity of flexible pavements is brought about by the load-distributing characteristics of the layered system. The behavior of such pavements under load is extremely complex. The stresses in the pavement can induce consolidation, shear failures, rutting, fatigue and other distress manifestations. Many methods are available for measuring various strength properties of base materials. These include the CBR test, Hveem Stabilometer Test, Plate Bearing Test, the Standard Triaxial Test, the Resilient Modulus Test (detailed) and others. Equivalency factors are discussed and it is pointed out that the use of such factors without considering the true characteristics of the material, climate and other factors can be dangerous. The designer must account for drainage, frost action, fatigue and many properties that are difficult to evaluate.

• Supplemental Notes:
  • Proceedings from a conference on Utilization of Graded Aggregate Base Materials in Flexible Pavements, March 25-26, 1974, Oak Brook Hyatt House, Oak Brook, Illinois.
• Corporate Authors:

  National Crushed Stone Association

  1415 Elliot Place, NW
  Washington, DC  United States  20007

  National Sand and Gravel Association

  900 Spring Street
  Silver Spring, MD  United States  20910

  National Slag Association

  300 South Washington Street
  Alexandria, VA  United States  22314
• Authors:
  • Yoder, E J
• Publication Date: 1974

Media Info

• Features: Appendices; Figures; Tables;
• Pagination: p. III1-12
• Serial:
  • Publication of: National Crushed Stone Association
  • Publisher: National Crushed Stone Association

Subject/Index Terms

• TRT Terms: Base course (Pavements); Coarse aggregates; Fatigue (Physiological condition); Fine aggregates; Flexible pavements; Frost action; Loads; Measurement; Pavement cracking; Pavement design; Pavement performance; Plastic deformation; Resilience (Materials); Shear strength; Stability (Mechanics); Strength of materials; Subbase (Pavements); Surface drainage; Thickness
• Uncontrolled Terms: Base; Loading; Subbase
• Old TRIS Terms: Graded coarse aggregate; Graded fine aggregate; Highway drainage; Slab action; Thickness equivalence
• Subject Areas: Highways; Pavements;

Filing Info

• Accession Number: 00127528
• Record Type: Publication
• Files: TRIS
• Created Date: Apr 7 1976 12:00AM