CHANGES IN FUNDAMENTAL PROPERTIES OF ASPHALTS DURING SERVICE IN PAVEMENTS

DURING 1954-1956 THE BUREAU OF PUBLIC ROADS COLLECTED OVER 300 ASPHALT CEMENT SAMPLES REPRESENTING OVER 100 REFINERY SOURCES IN THE U.S. THE ASPHALTS WERE IDENTIFIED WITH ABOUT 285 CONSTRUCTION PROJECTS WHERE THEY WERE USED. THE ASPHALTS SAMPLES WERE THOROUGHLY ANALYZED TO DETERMINE THEIR CHEMICAL AND PHYSICAL PROPERTIES. IN 1967 PUBLIC ROADS INITIATED A FIELD SURVEY AND DESIGNED A SAMPLING PLAN TO DETERMINE THE OVERALL CHANGES IN THE ASPHALTS DURING 11-13 YEARS OF SERVICE. A CONTRACT WAS AWARDED TO MATERIALS RESEARCH AND DEVELOPMENT TO ASSIST IN PLANNING AND EXECUTING THE FIELD SURVEY, DETERMINING THE CHEMICAL PROPERTIES OF THE RECOVERED ASPHALTS AND GLASS-TRANSITION TEMPERATURES OF SELECTED ASPHALTS BEFORE AND AFTER AGING IN SERVICE AND TO CONDUCT AN OVERALL ANALYSIS OF ALL INFORMATION AND TEST DATA COLLECTED. THE BUREAU OF PUBLIC ROADS DETERMINED THE PHYSICAL PROPERTIES OF THE PAVEMENT SAMPLES, EXTRACTED, RECOVERED, AND DETERMINED THE PHYSICAL PROPERTIES OF THE RECOVERED ASPHALTS AND MADE GRADATIONS AND IDENTIFICATION OF THE AGGREGATES. IN ADDITION, LABORATORY AGING TESTS WERE CONDUCTED BY THE CALIFORNIA DIVISION OF HIGHWAYS AND BY THE BUREAU OF PUBLIC ROADS. ALL DATA WERE FURNISHED THE CONTRACTORS FOR ANALYSIS. FIFTY-THREE PAVING PROJECTS LOCATED IN 19 STATES WERE SELECTED FOR STUDY. THE REPORT PREPARED BY THE CONTRACTOR INCLUDES DETAILED PROCEDURES USED IN THE SUBJECTIVE PAVEMENT CONDITION SURVEY AND IN LABORATORY TESTING OF MIXTURES, RECOVERED ASPHALTS, AND AGGREGATES. WITHIN PROJECT AND BETWEEN PROJECT VARIABILITY OF THE PROPERTIES OF PAVEMENT SAMPLES AND COMPONENT MATERIALS ARE SUMMARIZED. IN ADDITION TO THE ABOVE SEVERAL OTHER DETAILED STUDIES OF THE DATA ARE SUMMARIZED. THE MOST IMPORTANT CONCLUSIONS OF THIS DATA ANALYSIS ARE: (1) THE MOST IMPORTANT FACTOR IN HARDENING OF ASPHALT BINDER IN THE PAVEMENT IS THE VOIDS CONTENT OF THE PAVEMENT, (2) WIDE WITH-PROJECT VARIATION IN MIXTURE PROPERTIES AND PROPERTIES OF RECOVERED ASPHALTS EMPHASIZES THE NEED FOR MULTIPLE SAMPLES AND COMPLETE ANALYSIS OF THE SAMPLES TO OBTAIN RELIABLE DATA ON DURABILITY OF ASPHALTS AND PAVEMENTS, (3) THE CALIFORNIA WEATHERING OVEN AGING AND THE PUBLIC ROADS MODIFIED THIN-FILM OVEN AGING RESULTED IN HARDENING OF THE ASPHALT COMPARABLE TO 11 TO 13 AGING IN A PAVEMENT WITH ABOUT 4 PERCENT VOIDS, (4) THE TYPE OF CHEMICAL CHANGE TAKING PLACE IN LONG-TERM FIELD AGING DIFFERS SOMEWHAT FROM ACCELERATED LABORATORY AGING, AND (5) ATTEMPTS TO CORRELATE OBSERVED PAVEMENT DISTRESS WITH CONSTRUCTION VARIABLES, ENVIRONMENT, TRAFFIC HISTORY OR ORIGINAL AND PRESENT PROPERTIES OF ASPHALTS WERE THWARTED BY THE LARGE NUMBER OF VARIABLES BETWEEN PROJECTS. /BPR/

  • Corporate Authors:

    Materials Research & Development

    ,    

    Bureau of Public Roads /US

    400 7th Street, SW
    Washington, DC  United States  20590
  • Authors:
    • Vallerga, V A
    • White, R M
    • Rostler, K S
  • Publication Date: 0

Subject/Index Terms

Filing Info

  • Accession Number: 00210434
  • Record Type: Publication
  • Source Agency: Bureau of Public Roads /US
  • Contract Numbers: DOT-FH-11-6147
  • Files: TRIS
  • Created Date: Jul 14 1970 12:00AM