STUDY OF THE ELECTRO-CHEMICAL REACTIONS IN AN AGGREGATE- ASPHALT SYSTEM

STUDIES RELATING TO ASPHALT COMPOSITION AND TO THE ADHESION OF ASPHALT TO AGGREGATE IS SUMMARIZED. THE STUDIES WERE DESIGNED TO DEVELOP AN ADHESION THEORY BASED ON HYDROGEN BONDING AND RELATED PHENOMENA, SUCH AS VISCOSITY, FREE ENERGY OF ACTIVATION AND DIELECTRIC PROPERTIES, AND TO EXPLAIN THE MECHANISM INVOLVED IN ADHESION AND STRIPPING IN ASPHALT-AGGREGATE SYSTEMS. A QUANTITATIVE METHOD WAS DEVELOPED FOR ADDITIVES IN ASPHALTS USING INFRA-RED SPECTRA. AVERAGE HYDROGEN BONDING ENERGIES WERE ESTIMATED FOR 70/85 GRADE ASPHALTS AND FOR CUTBACKS IN TERMS OF GIBBS FREE ENERGY OF ACTIVATION DETERMINED FROM VISCOSITY DATA USING THE EYRING TRANSPORT THEORY. BONDING ENERGY FOR POLAR GROUPS IN AN SC-5 WAS DETERMINED FROM DIELECTRIC CONSTANT MEASUREMENTS OVER A RANGE OF TEMPERATURES. INFRA-RED ANALYSES WERE MADE ON ASPHALTS AND COMPONENTS OF ASPHALTS OBTAINED BY THE MARCUSSON AND BY THE TRAXLER-SCHWEYER FRACTIONATION METHODS. VARYING THICKNESSES OF TEST SPECIMENTS AND HIGH RESOLUTION EQUIPMENT GAVE COMPLEX SPECTRA INDICATING THE PRESENCE OF MANY FUNCTIONAL GROUPS AND ORGANIC LINKAGES. THE ADDITIVE CONTENT DETERMINATION USED SYNTHETIC MIXTURES MADE BY DISSOLVING VARIOUS ADDITIVES IN SOLVENTS SUCH AS BENZENE. THE ASSUMPTION WAS MADE THAT AGGREGATES CAN BE CLASSIFIED AS LEWIS ACIDS OR BASES AND THAT ACTIVATION ENERGY FOR ADSORPTION IS A MEASURE OF THE DEGREE OF SURFACE ACIDITY /OR BASICITY/. SINCE THEORY RELATES ACTIVATION ENERGY TO POLARIZABILITY AND TO ADSORPTION, THE LATTER WAS DETERMINED FOR SEVERAL AGGREGATES USING A POLAROGRAPH AND A STANDARD SULPHATE SOLUTION. RESULTS LED TO THE CONCLUSION THAT ADSORPTION MEASUREMENTS CAN SERVE TO CLASSIFY AGGREGATE SURFACES AS TO LEWIS ACIDITY OR BASICITY. A GOOD RELATION WAS FOUND BETWEEN AGGREGATE ADSORPTION AND STRIPPING RESISTANCE AND WITH ACIDITY CONCEPTS, FOR THE ASPHALTS WITH AND WITHOUT ADDITIVE.

  • Supplemental Notes:
    • Hpr-1/4/, ITEM-4, STATE R-7
  • Corporate Authors:

    Montana State Highway Commission

    ,    
  • Authors:
    • Wellman, R P
  • Publication Date: 1966-10

Subject/Index Terms

Filing Info

  • Accession Number: 00210371
  • Record Type: Publication
  • Source Agency: Bureau of Public Roads /US
  • Files: TRIS
  • Created Date: Jul 5 1994 12:00AM