RHEOLOGICAL BEHAVIOR OF ASPHALT PAVINGS UNDER TRAFFIC

THE COMPRESSION/TIME RELATION OF ASPHALT PAVINGS UNDER THE PRESSURE OF MOVING VEHICLE WHEELS HAS BEEN STUDIED BY THE USE OF A COMPRESSION GAUGE INSERTED IN THE PAVING UNDER THE WHEEL. THE PAVING IS IN SUCH A PROCESS SUBJECTED TO AN APPROXIMATELY CONSTANT PRESSURE DURING A SHORT PERIOD OF TIME (MILLISECONDS), AND THE COMPRESSION WAS FOUND TO INCREASE MONOTONOUSLY AND THEREAFTER TO DECREASE FOR A PERIOD OF TIME MANY TIMES LONGER THAN THE TIME OF LOADING. THE MAXIMUM COMPRESSION VARIED SLIGHTLY WITH THE POSITION UNDER THE TYRE/PAVING CONTACT AREA BUT DECREASED AT A CONSIDERABLE RATE WITH THE DISTANCE FROM THIS AREA. THE MAXIMUM COMPRESSION DECREASED WITH THE VEHICLE SPEED, EQUIVALENT TO AN APPROXIMATELY LINEAR INCREASE WITH TYRE/ PAVING CONTACT TIME. THE INITIAL SLOPE OF THE COMPRESSION/ TIME CURVE (RATE OF COMPRESSION) INCREASED WITH WHEEL SPEED BUT SHOWED QUITE A MODERATE VARIATION WITH AXLE LOAD. THE COMPRESSION RECOVERY, REPRESENTED BY THE TIME REQUIRED FOR DECAY FROM PEAK COMPRESSION TO 50% OF PEAK COMPRESSION (HALF TIME), INCREASED SLIGHTLY WITH AXLE LOAD AND DECREASED CONSIDERABLY WITH INCREASED WHEEL SPEED, I.E. REDUCED CONTACT TIME. THE BEHAVIOR SO FOUND HAS BEEN ILLUMINATED BY STUDYING CREEP AND RELAXATION OF BITUMINOUS MIXTURES AND ESPECIALLY CONSIDERING THE CHANGE OF THESE PROPERTIES WITH THE RATE OF APPLICATION OF LOAD AND THE RATE OF COMPRESSION PRECEDING THE CREEP AND RELAXATION PROCESSES. AN INCREASE IN THESE RATES IS KNOWN TO CHANGE THE TIME SCALE OF CREEP AND RELAXATION. THE MEAN RELAXATION TIME, DERIVED FROM THE INFLEXION POINT OF THE RELAXATION CURVE WHEN PLOTTED ON A LOGARITHMIC BASIS, DECREASED NEARLY LINEARLY WITH THE PRECEDING RATE OF COMPRESSION, BOTH PLOTTED ON A LOGARITHMIC SCALE. ALSO, "TIME OF EQUAL CREEP", DERIVED FROM CREEP CURVES AND EQUIVALENT TO THE "HALF TIME" DECREASED LINEARLY WITH THE RATE OF LOADING ON A LOGARITHMIC SCALE, CURVES FROM DIFFERENT BITUMENS AND DIFFERENT AGGREGATES BEING IDENTICAL. SIMILAR INFLUENCE OF THE RATE OF CHANGE OF PERTINENT QUANTITIES ON THE TIME SCALE OF RATE PROCESSES IS KNOWN FROM OTHER BRANCHES OF RHEOLOGY, ALTHOUGH ITS PRACTICAL IMPLICATIONS HAVE NOT BEEN EMPHASIZED, AND NO THEORETICAL EXPLANATION HAS SO FAR BEEN OFFERED. /AUTHOR/

• Supplemental Notes:
  • Preprint VoL, PP 374-383, 14 FIG, 14 REF
• Authors:
  • Andersson, O
• Conference:
  • Intl Conf Struct Design Asphalt Pvmts
• Publication Date: 1967-1

Subject/Index Terms

• TRT Terms: Asphalt pavements; Axle load force; Bituminous mixtures; Compression; Measurement; Motion; Motor vehicles; Rheology; Speed; Time; Vehicles; Wheels
• Uncontrolled Terms: Moving vehicles
• Old TRIS Terms: Compression ratio; Relaxation time
• Subject Areas: Highways; Pavements; Vehicles and Equipment;

Filing Info

• Accession Number: 00206641
• Record Type: Publication
• Files: TRIS
• Created Date: Sep 27 1994 12:00AM