CAUSES OF RIPPLES IN HOT MIX

THE MORE OR LESS REGULARLY SPACED SHALLOW WAVES FOUND IN CERTAIN HOT MIX ASPHALT PAVEMENTS HAVE BEEN TERMED RIPPLES. RIPPLES ARE VISIBLE IMMEDIATELY AFTER CONSTRUCTION AND FOR THIS REASON ARE BELIEVED TO BE BUILT IN DURING CONSTRUCTION. THEY REMAIN VISIBLE FOR SEVERAL YEARS AND ARE NOT IRONED OUT BY TRAFFIC. THIS INDICATES THAT RIPPLES ARE CAUSED BY MORE VOLUME, OR POUNDS OF MIX, BEING PLACED AT THE CREST OF THE WAVE THAN IN THE TROUGH. SOME HAVE FOUND THAT RIPPLES DEVELOP MORE OFTEN IN FINE MIXES AND MIXES OF LOW STABILITY. ONE SOLUTION FOR CURING RIPPLES IS CHANGING THE SEQUENCE OF WEIGHING AGGREGATES. IN SOME CASES RIPPLES CAN BE REDUCED BY CUTTING DOWN ON THE AMOUNT OF FINES. RIPPLING CAN BE KEPT WITHIN ACCEPTABLE BOUNDS BY ONE OR MORE OF THE FOLLOWING ACTIONS: (1) USING A VIBRATORY RATHER THAN A TAMPER-BAR SCREED, (2) USING SILICONE IN THE ASPHALT, (3) USING AN ADJUSTABLE STRIKE-OFF AHEAD OF THE SCREED, (4) ENSURING DRY SAND, (5) USING AS HARD AN ASPHALT AS POSSIBLE, AND (6) AS A LAST RESORT, CHANGING FINE SAND. RIPPLING IS LIKENED TO TRACKED VEHICLES PUSHING THE SNOW IN TRAFFICABILITY TESTS. THE SIMILARITY INDICATES THAT RIPPLES IN HOT MIX ARE PRODUCED BY THE SCREED PUSHING MIX AHEAD UNTIL A BULGE OR A RESULT OF COMPACTED MIX IS PRODUCED. RIPPLING APPEARS TO OCCUR IN MIXES THAT HAVE LOW STABILITY AND LIE DOWN AND THAT ARE LAID WITH A PAVER THAT TENDS TO PUSH MIX AHEAD OF THE SCREED.

  • Supplemental Notes:
    • pp 1-8, 3 FIG, 2 REF
  • Corporate Authors:

    Louisiana State University and Agriculture & Mechanical College, Baton Rouge

    Highway Engineering Conference
    Baton Rouge, LA  USA  70803
  • Authors:
    • Foster, C R
  • Publication Date: 1968-2

Subject/Index Terms

Filing Info

  • Accession Number: 00214820
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Jun 18 1994 12:00AM