DEFLECTION CRITERIA FOR FLEXIBLE PAVEMENTS AND THE DESIGN OF OVERLAYS
THE LONG-TERM PERFORMANCE OF FLEXIBLE PAVEMENTS CAN BE DETERMINED BY THE MAGNITUDE OF THE TRANSIENT DEFLECTIONS WHICH OCCUR UNDER TRAFFIC. A CONTINUOUS PROGRAM OF DEFLECTION MEASUREMENTS EXTENDING OVER FIFTEEN YEARS HAS BEEN CARRIED OUT THROUGH FULL-SCALE ROAD EXPERIMENTS. OVER 300 EXPERIMENTAL SECTIONS AND, IN ADDITION, 30 LENGHTS OF MAJOR ROAD WHOSE CONSTRUCTION IS OF PARTICULAR INTEREST HAVE BEEN TESTED ANNUALLY WITH THE BENKELMAN DEFLECTION BEAM UNDER A WHEEL-LOAD OF 3175 KG (7000 LB). THE MEASURED DEFLECTIONS HAVE BEEN CORRECTED FOR THE INFLUENCE OF TEMPERATURE ON THE STIFFNESS OF THE BITUMINOUS COMPONENTS, AND THESE STANDARD DEFLECTIONS AT 20 DEGREES C HAVE BEEN RELATED: (A) TO THE AGE OF THE ROAD EXPRESSED IN TERMS OF THE CUMULATIVE TOTAL OF EQUIVALENT STANDARD 8200 KG (18,000 LB) AXLE LOADS CARRIED; AND (B) TO THE CONDITION OF THE PAVEMENT IN TERMS OF RUTTING AND CRACKING. THE DEFLECTION HISTORIES THUS DERIVED ENABLE THE DEVELOPMENT OF CRITICAL CONDITIONS WITHIN THE PAVEMENT WHEN STRENGTHENING OF THE ROAD WOULD BE MOST APPROPRIATE, TO BE RELATED TO DEFLECTION BEHAVIOR UNDER TRAFFIC. OVERLAYS HAVE BEEN APPLIED TO CERTAIN FULL-SCALE ROAD EXPERIMENTS AS THEY HAVE BEEN RETIRED FROM SERVICE AND DEFLECTION STUDIES HAVE BEEN CONTINUED. THE BEHAVIOR OF OVERLAYS LAID TO STRENGTHEN NORMAL ROADS IN BEING SIMILARLY STUDIED. DEFLECTION HISTORIES OF OVERLAID PAVEMENTS HAVE BEEN USED TO PREPARE RECOMMENDATIONS FOR OVERLAY THICKNESSES TO ACHIEVE ANY REQUIRED EXTENSION OF PAVEMENT LIFE. THE IMPLEMENTATION OF RECOMMENDATIONS FOR PAVEMENT STRENGTHENING IS CONSIDERED. /AUTHOR/
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Authors:
- Lister, N W
- Conference:
- Publication Date: 1972-9
Media Info
- Features: Figures; References; Tables;
- Pagination: 21 p.
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Serial:
- Volume: 1
Subject/Index Terms
- TRT Terms: Deflection; Flexible pavements; Overlays (Pavements); Pavement performance; Pavements; Thickness; Wheel loads
- Old TRIS Terms: Pavement deflection
- Subject Areas: Highways; Pavements;
Filing Info
- Accession Number: 00206052
- Record Type: Publication
- Files: TRIS
- Created Date: May 7 1973 12:00AM