PHYSICOCHEMICAL ASPECTS OF ASPHALT PAVEMENTS: ENERGY RELATIONS AT INTERFACE BETWEEN ASPHALT AND MINERAL AGGREGATE AND THEIR MEASUREMENTS

ENERGY RELATIONS AT THE INTERFACE BETWEEN ASPHALT AND MINERAL AGGREGATE WERE MEASURED AND CORRELATED WITH BEHAVIOR AND STABILITIES OF ASPHALT PAVEMENTS EXPOSED TO WATER. THE MOST IMPORTANT ENERGY RELATION IS THE INTERFACIAL TENSION BETWEEN SOLIDS AND LIQUIDS. TYPICALLY HYDROPHILIC SOLIDS HAVE ENERGY RELATIONS AT THEIR INTERFACES WITH PURE LIQUIDS WHICH ARE APPROXIMATELY THE SAME AS AT THE INTERFACE BETWEEN WATER AND LIQUID. TO ILLUSTRATE THIS, ADHESION TENSION OF 17 LIQUIDS AGAINST QUARTZ WERE SHOWN TO BE QUITE SIMILAR TO THE INTERFACIAL TENSION OF THE SAME LIQUIDS AND WATER. ADHESION TESTS AGAINST CARBON WERE VASTLY DIFFERENT. A SIMPLE METHOD WAS DEVISED TO MEASURE INTERFACIAL TENSION BETWEEN SOLIDS AND LIQUIDS WHICH ALLOWS THE POWDERED SOLID TO SETTLE FREELY FROM THE LIQUID. WITH FEW EXCEPTIONS, THE VOLUME TO WHICH THE POWDER SETTLES IS PROPORTIONAL TO THE INTERFACIAL TENSION BETWEEN THE TWO PHASES. IN THE CASES CITED FOR HYDROPHILIC SILICA, LIMESTONE AND BLUE CLAY, THE SETTLING VOLUMES OF THE POWDERS DECREASE WITH THE INTERFACIAL TENSION OF THE LIQUID, AND INCREASE FOR THE HYDROPHOBIC CARBON BLACK. THIS RELATIONSHIP DOES NOT HOLD FOR ASPHALT. SILICA HAS AN INTERFACIAL TENSION AGAINST THE SIX ASPHALTS INVESTIGATED WHICH ARE HIGHER THAN THOSE AGAINST WATER. LIMESTONE AND BLUE CLAY HAVE NEGATIVE INTERFACIAL TENSION AGAINST THE ASPHALTS. THIS DEVIATION FROM PURE LIQUIDS IS ASCRIBED TO A DIFFERENCE IN ABSORPTION OF CERTAIN ASPHALTIC COMPONENTS ON THE SURFACE OF THE SOLID AND WATER. ENERGIES OF ADHESION AND COEFFICIENTS OF SPREADING WERE CALCULATED FROM INTERFACIAL TENSION OF ASPHALT AGAINST AGGREGATE AND THE SURFACE TENSION OF ASPHALTS. THE DEGREE OF WETTING IS INDEPENDENT OF THE VISCOSITY OF THE LIQUID AND THE DIAMETERS OF CAPILLARIES ON THE POWDER. ASPHALTS WHICH HAVE A HIGH COEFFICIENT OF SPREADING TOWARDS AN AGGREGATE, POSSESS A HIGH DEGREE OF WETTABILITY FOR THE SOLID, RESULTING IN A THIN FILM OF ASPHALT. AN ACCURATE ACCOUNT IS GIVEN OF THE PHYSICOCHEMICAL PROPERTIES OF BITUMINOUS MIXTURES.

  • Supplemental Notes:
    • Vol 27, pp 1500-1505
  • Authors:
    • Mack, C
  • Publication Date: 1935

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  • Accession Number: 00206776
  • Record Type: Publication
  • Files: TRIS
  • Created Date: May 21 1994 12:00AM