AN INVESTIGATION OF ASPHALT-AGGREGATE ADHESION BY MEASUREMENTS OF HEATS OF IMMERSION

IN SPITE OF THE DIVERSIFIED ATTACK ON THE PROBLEMS OF ASPHALTS AND THEIR ADHESION TO AGGREGATES---21 ARE ENUMERATED IN THE INTRODUCTION---VERY LITTLE ATTENTION HAS BEEN GIVEN TO THERMODYNAMIC APPLICATIONS. ALTHOUGH THE INSTRUMENTATION REQUIRED TO MEASURE THE ENERGY RELEASED IN CHEMICAL CHANGES MAY BE QUITE ELABORATE, IT USUALLY DOES NOT HAVE TO BE AS SENSITIVE AS THAT REQUIRED TO DETECT THE SMALL AMOUNT OF ENERGY RELEASED IN PHYSICAL CHANGES. (ADHESION, WITHOUT CHEMISORPTION, IS CLASSED AS A PHYSICAL CHANGE.) FOLLOWING A SURVEY OF THE THEORY OF ADHESION AND SOME ANALYSIS OF CONTACT ANGLE STUDIES, IT IS NOTED THAT FOR MANY YEARS BONDING HAS BEEN APPROACHED THROUGH STUDIES OF THE ENERGY RELEASED WHEN A SOLID IS IMMERSED INTO A LIQUID TO DETERMINE THE AVERAGE POLARITY OF SOLID SURFACES, SITE ENERGY DISTRIBUTION OR HETEROGENEITY OF SOLID SURFACES, HEAT OF FORMATION OF DOUBLE LAYERS, FOREIGN MATERIAL ON THE SURFACE, ADDITIVES TO THE ADSORBATE, ETC. WHILE SENSITIVE TO MANY PARAMETERS, THIS METHOD HAD THE DRAWBACK THAT REPRODUCIBILITY DEPENDS ON EXTREME CAUTION WITH REGARD TO PURITY AND TREATMENT OF THE ABSORBENT AND ABSORBATE. ON THE ASSUMPTION THAT THE ENERGY RELEASED UPON IMMERSION INCREASES WITH THE STRENGTH OF THE SOILD--LIQUID INTERACTION, AND THE COROLLARY THAT GREATER HEATS OF IMMERSION INDICATE STRONGER BONDS AND MORE DURABLE HIGHWAYS, A STUDY WAS UNDERTAKEN TO DEVELOP SUITABLE EQUIPMENT AND TO CONDUCT EXPERIMENTS TO MEASURE THE HEATS OF IMMERSION OF ASPHALTIC AND OTHER MATERIALS. IT IS CONCLUDED THAT THE MICROCALORIMETER DESIGNED FOR THE EXPERIMENTS IS EXTREMELY SENSITIVE, THAT ENERGY RELEASE IS STRONGLY DEPENDENT ON ASPHALT ADDITIVES, AND THAT ADSORPTION OF ASPHALT ON THE TESTED AGGREGATES IS A SLOW PROCESS WHICH WOULD PROBABLY CONTINUE FOR MANY HOURS IF THE ASPHALT AND AGGREGATE WERE HELD IN CONCTACT AT HIGH TEMPERATURES. RECOMMENDATIONS FOR USING THE MICROCALORIMETER IN HIGHWAY CONSTRUCTION ARE MADE, AND DIRECTIONS FOR FURTHER RESEARCH ARE INDICATED.

  • Supplemental Notes:
    • 46 Pp, 21 FIG, 28 REF
  • Corporate Authors:

    Montana College of Mineral Science and Technology

    Butte, MT  USA 
  • Authors:
    • Ensley, E K
    • Scholz, H A
  • Publication Date: 0

Subject/Index Terms

Filing Info

  • Accession Number: 00211582
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Apr 25 1971 12:00AM