ADDITIVES AND ADMIXTURES FOR ASPHALT CONCRETE - ASBESTOS, RUBBER, TALC, AND HYDRATED LIME

THE INFLUENCE VARIOUS ADMIXTURES HAVE ON THE PERFORMANCE OF ASPHALT CONCRETE SURFACE COURSE MIXTURES WAS DETERMINED. TEST PAVEMENTS, WITH CONTROL SECTIONS, WERE CONSTRUCTED CONTAINING ASBESTOS AND TALC FIBERS, CRUMB AND FIBERS, CRUMB AND LATEX RUBBER PRODUCTS, AND HYDRATED LIME AS ADMIXTURES. FOUR TEST PAVEMENTS CONTAINING ASBESTOS WERE OBSERVED FOR PERIODS OF FROM 4 TO 10 YEARS. IT IS CONCLUDED THAT THE ASBESTOS FIBER DID NOTHING TO IMPROVE THE PERFORMANCE OR SKID RESISTANCE OF CONCRETE MIXTURES CONTAINING AN APPRECIABLE COARSE AGGREGATE CONTENT. THREE TEST PAVEMENTS CONTAINING TALC FIBER HAVE BEEN OBSERVED FOR PERIODS RANGING FROM 4 TO 6 YEARS. THOUGH THIS ADMIXTURE PRODUCED AN INCREASE IN THE STRENGTH PROPERTIES OF BITUMINOUS MIXTURES AS MEASURED IN THE LABORATORY, NO MARKED BENEFITS WERE NOTED IN PAVEMENT PERFORMANCE. FIVE TEST PAVEMENTS INCORPORATING EITHER CRUMB OR LATEX RUBBER PRODUCTS HAVE BEEN OBSERVED FOR A PERIOD OF 2 TO 4 YEARS. NEITHER OF THESE ADDITIVES IMPARTED ANY BENEFICIAL EFFECTS TO STANDARD TOP COURSE MIXTURES, AS JUDGED BY THE PHYSICAL PROPERTIES OF CORE SAMPLES REMOVED FROM THE PAVEMENTS OR BY VISUAL COMPARISON OF TEST AREAS AND CONTROL AREAS. TWO TEST PAVEMENTS CONTAINING HYDRATED LIME HAVE BEEN OBSERVED FOR SIX YEARS. THE AGGREGATES USED IN THESE PAVEMENTS WERE OF HIGH QUALITY, FREE OF DUST OR CLAY COATINGS, AND THEREFORE THE ADDITION OF LIME WOULD NOT HAVE SIGNIFICANTLY AFFECTED THE MIXTURE PROPERTIES. THE USE OF HYDRATED LIME AS A MINERAL FILLER IS NOT RECOMMENDED IN SURFACE COURSE MIXTURES HAVING ACCEPTABLY PROCESSED AND WASHED AGGREGATES. BASING CONCLUSIONS ON THE VISUAL OBSERVATIONS OF THE TEST SECTIONS, IT WAS CONCLUDED THAT THESE ADMIXTURES HAVE LITTLE OR NO EFFECT ON THE PERFORMANCE OF THE NYS STANDARD SURFACE COURSE MIXTURES USED IN THE INVESTIGATION. HOWEVER, THESE ADDITIVES MAY HAVE BENEFICIAL EFFECTS IN SPECIAL MIXTURES SUCH AS A CURBING MIX OR A FINE SAND SHEET MIX, OR POSSIBLY WITH MARGINAL MATERIALS. /BPR/

  • Corporate Authors:

    New York State Department of Transportation

    1220 Washington Avenue
    Albany, NY  United States  12232

    Bureau of Public Roads /US

    400 7th Street, SW
    Washington, DC  United States  20590
  • Authors:
    • Thomas, J J
    • Clark, W H
    • Molinaro, T F
    • ZDEB, M S
  • Publication Date: 0

Subject/Index Terms

Filing Info

  • Accession Number: 00210427
  • Record Type: Publication
  • Source Agency: Bureau of Public Roads /US
  • Report/Paper Numbers: 20-5
  • Files: TRIS, STATEDOT
  • Created Date: May 13 1970 12:00AM