OPTIMAL DESIGN OF ASPHALT OVERLAYS

This paper presents a new method for designing asphalt overlays when optimization is required at least from an economic standpoint. Two main situations are taken into account: the existing pavement needs only to be strengthened as no important distorsions are reported, the existing pavement is heavily rutted, cracked or disintegrated and it is supposed to undergo particularly deep investigation and--if necessary--a new and complete structural design would be done. Only the first situation is studied in this paper. The new method is based upon an energy approach which requires that the energy absorbed by the highway body, when deflection under exterior loading occurs, should not exceed a limited amount which is related to the composition and the value of the traffic the pavement is supposed to bear through the design period. The design criteria are based upon limiting tensile stresses at the bottom of the layers, shear stresses in the center plane of the layers and--most of all--requiring given bearing capacity of the "rejuvenated" pavement. Since only one layer (as overlay) may not fullfill all requirements derived from the design criteria, it has been assumed that in certain situations two layers would be necessary, such a solution being supposed to offer both economic and constructive advantages. The method also permits an iterative procedure in order to get an economic optimum. Since new developments have been made, both theoretical and experimental accuracy checks have been done. The method has been accepted for current overlay design and is now in use in parallel with the existing standardized method.

• Supplemental Notes:
  • Volume I of proceedings of 4th International Conference on Structural Design of Asphalt Pavements, Ann Arbor, Michigan, August 22-26, 1977.
• Corporate Authors:

  University of Michigan, Ann Arbor

  Department of Civil Engineering
  Ann Arbor, MI  United States  48109
• Authors:
  • Ratiroiu, M D
• Conference:
  • Volume I of proceedings of 4th International Conference on Structural Design of Asphalt Pavements, Ann Arbor, Michigan, August 22-26, 1977.
• Publication Date: 1977-1

Media Info

• Features: Figures; References; Tables;
• Pagination: p. 697-709

Subject/Index Terms

• TRT Terms: Asphalt pavements; Deflection; Flexible pavements; Loads; Optimization; Overlays (Pavements); Pavement cracking; Pavement design; Pavements; Ruts (Pavements); Shear stress; Tension
• Uncontrolled Terms: Loading; Rut; Tensile stress
• Old TRIS Terms: Pavement deflection
• Subject Areas: Highways; Pavements;

Filing Info

• Accession Number: 00170244
• Record Type: Publication
• Report/Paper Numbers: Proceeding
• Files: TRIS
• Created Date: Mar 29 1978 12:00AM