BEARING STRENGTH DETERMINATION ON BITUMINOUS PAVEMENTS BY THE METHODS OF CONSTANT RATE OF LOADING OR DEFORMATION

IT IS THE PURPOSE OF THIS PAPER TO SHOW, BOTH THEORETICALLY AND EXPERIMENTALLY, THAT TIME-SAVING METHODS USING CONSTANT RATE OF LOADING OR DEFORMATION ARE SUITABLE FOR THE DETERMINATION OF BEARING STRENGTH. BEARING STRENGTH MEASUREMENTS CARRIED OUT IN DUPLICATE UNDER A CONSTANT LOADING RATE OF 1 LB. PER SECOND ON SAND-ASPHALT MIXTURES CONTAINING VARIOUS AMOUNTS OF TWO DIFFERENT ASPHALTS SHOWED GOOD REPRODUCIBILITY OF RESULTS. THE BEARING STRENGTH INCREASED TO AN OPTIMUM WITH ASPHALT CONTENT. FOR THERMODYNAMIC REASONS, A DEVIATION IN THE VALUE OF THE BEARING STRENGTH IS EXPECTED AT HIGH RATES OF LOADING OR DEFORMATION. FOR THE DETERMINATION OF THE RATE LIMIT, THE SAND-ASPHALT MIXTURES AT OPTIMUM ASPHALT CONTENT WERE SUBJECTED TO CONSTANT LOADING RATES OF 1, 2, 4, 8 AND 16 LB. PER SECOND. THE BEARING STRENGTHS OBTAINED WERE REPRODUCIBLE AT RATES UP TO 4 LB. PER SECOND, AND WERE IN GOOD AGREEMENT WITH THE VALUES MEASURED BY STATIC LOAD TESTS AT ZERO RATE OF LOADING. THE EFFECT OF CONSTANT RATES VARIES WITH THE DIMENSIONS OF THE SAMPLE, THE UPPER LIMIT FOR CONSTANT RATE OF LOADING IS 1.27 PSI PER SECOND, AND FOR CONSTANT RATE OF DEFORMATION THE UPPER LIMIT IS OF THE ORDER OF .00015 TO .0002 IN. PER INCH THICKNESS PER SECOND. IT IS GENERALLY ASSUMED THAT THE MAGNITUDE OF THE COMPACTIVE EFFORT AFFECTS THE STABILITY OF BITUMINOUS PAVEMENTS. TO TEST THIS ASSUMPTION, AN ASPHALTIC CONCRETE MIXTURE WAS COMPACTED BY THE MARSHALL METHOD USING 25, 50 AND 75 BLOWS, AND THE SAMPLES WERE SUBJECTED TO A CONSTANT STRAIN RATE OF .00019 IN. PER SECOND. THE BEARING STRENGTH WAS THE SAME IN EACH CASE. HOWEVER, INCREASING THE DEGREE OF COMPACTION REDUCED THE WORK REQUIRED TO OBTAIN THE BEARING STRENGTH. THE METHOD OF CONSTANT RATE OF LOADING OR DEFORMATION ALSO CAN BE APPLIED FOR THE DETERMINATION OF THE BEARING STRENGTH OF GRANULAR MATERIALS AND SOILS. THE KNOWLEDGE OF THESE STRENGTHS SERVES AS A BASIS FOR THE DESIGN OF BITUMINOUS PAVEMENTS. /AUTHOR/

• Record URL:
  https://onlinepubs.trb.org/Onlinepubs/hrbproceedings/36/36-018.pdf
• Supplemental Notes:
  • Vol 36, pp 221-232, 5 FIG, 2 TAB, 3 REF, APP. 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:
  • Mack, C
• Publication Date: 1957

Media Info

• Media Type: Digital/other
• Monograph Title: Proceedings of the Thirty-Sixth Annual Meeting of the Highway Research Board, Washington, D.C., January 7-11, 1957
• Serial:
  • Highway Research Board Proceedings
  • Volume: 36
  • Publisher: Highway Research Board

Subject/Index Terms

• TRT Terms: Bearing tests; Bituminous pavements; Deformation; Deformation curve; Loads
• Uncontrolled Terms: Loading rate
• Subject Areas: Highways; Pavements;

Filing Info

• Accession Number: 00207348
• Record Type: Publication
• Files: TRIS, TRB
• Created Date: May 22 1972 12:00AM