USE OF HYDRATED LIME IN BITUMINOUS MIXTURES TO DECREASE HARDNESS OF THE ASPHALT CEMENT

WHEN ASPHALTIC CEMENT HARDENS, CRACKING AND RAVELING OCCUR WHICH CAUSE DETERIORATION OF THE PAVEMENT. IT WAS FOUND THAT THE ADDITION OF HYDRATED LIME IN BITUMINOUS MIXTURES DECREASES THE RATE OF HARDENING OF THE ASPHALT, THEREBY PROLONGING THE LIFE OF THE PAVEMENT. THE EVALUATION OF THE EFFECTS OF HYDRATED LIME ON ASPHALTIC PAVEMENTS WAS BASED ON VISCOSITY MEASUREMENTS OF THE EXTRACTED ASPHALTS, BECAUSE LOWERING OF VISCOSITY IS AN INDICATION OF REDUCTION OF HARDNESS OF THE ASPHALT. FIELD AND LABORATORY STUDIES WERE CONDUCTED ON COMBINATIONS OF ASPHALTS AND AGGREGATES WITH AND WITHOUT HYDRATED LIME. THE VISCOSITIES OF THE ASPHALTS EXTRACTED FROM BITUMINOUS MIXTURES WITH HYDRATED LIME AS AN ADDITIVE WERE LOWER THAN THE VISCOSITIES OF ASPHALTS EXTRACTED FROM THE SAME BITUMINOUS MIXTURES WITHOUT HYDRATED LIME. ALONG WITH THE DECREASE IN VISCOSITY, AN INCREASE IN THE DUCTILITY OF THE ASPHALTS WAS OBSERVED. THERE EXIST CONTRADICTORY EXPLANATIONS REGARDING THE CHEMICAL REACTIONS IN THE BITUMINOUS MIXTURE WHEN HYDRATED LIME IS ADDED. SOME RESEARCHERS BELIEVE THAT HYDRATED LIME ACTS AS A CATALYST, OTHERS THAT IT REACTS WITH THE ACIDIC AGGREGATE IN THE BITUMINOUS MIXTURES, AND OTHERS THAT IT REACTS WITH THE ASPHALT TO FORM SOAPS. IT IS THE OPINION OF THE AUTHORS BASED ON THE PRESENT DATA, THAT A SAPONIFICATION REACTION OCCURS WHICH RESULTS IN SOFTENING OF THE ASPHALTS STUDIED. /FHWA/

  • Supplemental Notes:
    • REPORT NO 500-909
  • Corporate Authors:

    Utah State Department of Highways

    757 West Second South
    Salt Lake City, UT  USA  84104
  • Authors:
    • Chachas, C V
  • Publication Date: 1971-12

Media Info

  • Pagination: 74 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00210480
  • Record Type: Publication
  • Source Agency: Federal Highway Administration
  • Files: TRIS, USDOT
  • Created Date: Apr 8 1973 12:00AM