OVERLAY DESIGN OF FLEXIBLE PAVEMENTS: OAF PROGRAM
A fully computerized rational method for the design of flexible overlays of flexible pavements is presented. The overlay thickness is determined based on a fatigue distress function developed from analyzing AASHO Road Test data. It relates horizontal tensile strain in the asphalt layer to the number of equivalent 18-kip (80-kN) axle loads to failure. A rutting criterion is not included because (a) rutting in unbound layers has generally stabilized by the time an overlay is contemplated, (b) rutting in the asphalt layer can be controlled by proper mix design, (c) the addition of an overlay decreases the stresses in the unbound layers, and (d) fatigue requirements generally dictate the overlay thicknesses. The existing pavement is evaluated by using nondestructive dynamic deflection measurements and a visual survey that includes general observations of drainage, the existence of rutting, and the presence and type of cracking. The deflection data are analyzed by using linear elastic theory in which the existing pavement is represented by a four-layer model consisting of a pavement layer, base and subbase layers, and a subgrade layer. The in situ layer stiffnesses are determined by matching measured deflections with those computed from layer theory. The design procedure recognizes that asphalt modulus is temperature-dependent. The in situ asphalt modulus is modified for temperature effects, and this adjusted modulus is used in design computation. The base and subgrade materials are corrected for stress effects when the state of stress is changed as a result of adding an overlay. The procedure also incorporates an environmental factor.
- Record URL:
- Summary URL:
-
Availability:
- Find a library where document is available. Order URL: http://worldcat.org/isbn/0309036208
-
Supplemental Notes:
- Publication of this paper sponsored by Committee on Pavement Rehabilitation. Distribution, posting, or copying of this PDF is strictly prohibited without written permission of the Transportation Research Board of the National Academy of Sciences. Unless otherwise indicated, all materials in this PDF are copyrighted by the National Academy of Sciences. Copyright © National Academy of Sciences. All rights reserved
-
Authors:
- Majidzadeh, Kamran
- Ives, George J
- May, Richard W
- Publication Date: 1983
Media Info
- Media Type: Print
- Features: Figures; References; Tables;
- Pagination: pp 18-25
- Monograph Title: Pavement design, performance, and rehabilitation
-
Serial:
- Transportation Research Record
- Issue Number: 930
- Publisher: Transportation Research Board
- ISSN: 0361-1981
Subject/Index Terms
- TRT Terms: Axle load force; Base course (Pavements); Computer aided design; Deflection; Dynaflect; Failure; Fatigue (Mechanics); Flexible pavements; Overlays (Pavements); Pavement design; Stiffness; Stresses; Subgrade (Pavements); Surveying; Tension; Thickness
- Uncontrolled Terms: Visual surveys
- Old TRIS Terms: Dynaflect deflections
- Subject Areas: Design; Highways; Maintenance and Preservation; Materials; Pavements; I22: Design of Pavements, Railways and Guideways;
Filing Info
- Accession Number: 00385684
- Record Type: Publication
- ISBN: 0309036208
- Files: TRIS, TRB
- Created Date: Jul 30 1984 12:00AM