ADHESION TENSION IN ASPHALT PAVEMENTS, ITS SIGNIFICANCE AND METHODS APPLICABLE IN ITS DETERMINATION

THE IMPORTANCE IS STRESSED OF SURFACE ACTIVITY AT A SOLID- LIQUID INTERFACE AS IT AFFECTS AN ASPHALT PAVEMENT. VARIOUS CONCEPTS SUCH AS ADHESION, COHESION, SURFACE TENSION, WETTING AND WORK OF IMMERSION ARE DEFINED AND GRAPHICALLY ILLUSTRATED. METHODS OF MEASUREMENT ARE DESCRIBED. NELLENSTEYN'S BUBBLE METHOD FOR SURFACE TENSION MEASUREMENT OF ASPHALTS IS REVIEWED. BARTELL'S WORK ON THE MEASUREMENT OF SURFACE ACTIVITY AT SOLID LIQUID INTERFACES IS DESCRIBED IN DETAIL. USING THE CAPILLARY TUBE METHOD, BARTELL COMPRESSES POWDERED MATERIAL OF UNIFORM PARTICLE SIZE IN BRASS DISPLACEMENT CELLS OF SAME SIZE AND SHAPE AS THOSE IN THE DETERMINATION OF ADHESION TENSION. THE METHOD IS ACCURATE BUT TEDIOUS AND TIME-CONSUMING. AS SUCH, IT IS NOT APPLICABLE TO ROUTINE MEASUREMENT OF SURFACE ACTIVITY AT AGGREGATE-ASPHALT INTERFACES. THE ADHESION TENSION OF 13 DIFFERENT PETROLEUM CRUDES FOR SILICA WAS DETERMINED BY THIS METHOD. THESE VALUES RANGED FROM 58.87 TO 72.68 DYNES/SQ CM., AS COMPARED TO 82.64 DYNES/SQ CM. FOR WATER-SILICA INTERFACES. THIS EXPLAINS THE TENDENCY OF WATER TO DISPLACE OILS FROM CRUDE OIL FORMATIONS AND IS ASSOCIATED WITH THE STRIPPING TENDENCY OF ASPHALT FROM MINERAL AGGREGATES. NUMEROUS TESTS WERE MADE ON THE STRIPPING OF ASPHALTS FROM VARIOUS TYPE MINERAL AGGREGATES. THE METHOD USED IS THE NICHOLSON TEST, WHERE THE COATED AGGREGATE IS IMMERSED IN WATER AND AGITATED FOR A SPECIFIED TIME TO DETERMINE THE EXTENT OF UNCOATING. THE UNIQUENESS OF ROCK ASPHALTS IS ILLUSTRATED. THIS MATERIAL DOES NOT UNCOAT UNDER THE TEST CONDITIONS EMPLOYED. NO EXPLANATION FOR THE STRONG ADHESIVITY OF ROCK ASPHALTS IS GIVEN.

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Filing Info

  • Accession Number: 00206775
  • Record Type: Publication
  • Source Agency: Highway Research Board Bibliography
  • Report/Paper Numbers: pp 28-49
  • Files: TRIS
  • Created Date: May 13 1994 12:00AM