EXPANDED CLAY HOT MIX STUDY

THIS IS PART I OF A TWO PART FINAL REPORT ON EXPANDED CLAY HOT MIX TO: (1) EVALUATE THE USE OF VARIOUS EXPANDED CLAY BITUMINOUS MIXTURES UNDER HEAVY TRAFFIC, (2) DETERMINE ADEQUATE AGGREGATE AND MIXTURE TESTING PROCEDURES AND CONSTRUCTION CONTROL PROCEDURES, AND (3) PREPARE A SUITABLE SPECIFICATION FOR EXPANDED CLAY BITUMINOUS MIXTURES. FOUR STANDARD GRAVEL HOT MIX CONTROL SECTIONS AND SIXTEEN EXPANDED CLAY HOT MIX SECTIONS WITH VARYING PERCENTAGE OF EXPANDED CLAY AGGREGATE, MINERAL FILLER, AND ASPHALT WERE EVALUATED. THE EVALUATION CONSISTED OF A STUDY OF THE PHYSICAL PROPERTIES OF THE PLANT MIXES, THE LAYDOWN AND COMPACTION OPERATION, DENSITY AND VOID ANALYSIS OF CORES TAKEN FROM THE PAVEMENT IMMEDIATELY AFTER CONSTRUCTION AND ONE YEAR LATER, ROUGHNESS MEASUREMENTS, SKID RESISTANCE AND PRESENT SERVICEABILITY INDEX MEASUREMENTS AT FOUR MONTH INTERVALS AFTER CONSTRUCTION. EXPANDED CLAY HOT MIXES APPEAR TO BE SATISFACTORY FOR BITUMINOUS PAVEMENT CONSTRUCTION. PROBLEMS WERE ENCOUNTERED IN DETERMINING THE TRUE DENSITY OF PAVEMENTS AFTER ROLLING AND THE CORRECT VALUES OF VOIDS AND RELATED PROPERTIES DUE TO THE GREAT DIFFERENCES IN SPECIFIC GRAVITIES OF THE EXPANDED CLAY AND THE SAND AND FILLER COMPONENTS OF THE AGGREGATE MIXTURES. IN THIS STUDY IT WAS FOUND NECESSARY TO EXTRACT THE ASPHALT FROM THE PAVING MIXTURES AND DETERMINE THE ACTUAL PERCENTAGE OF EXPANDED CLAY IN THEM. CORRECTIONS WERE THEN MADE FOR THE THEORETICAL MAXIMUM DENSITY VALUES IN ORDER TO OBTAIN THE CORRECT DENSITY AND PERCENTAGE OF AIR VOIDS IN THE PAVEMENTS. THE AVERAGE SKID NUMBERS FOR THE EXPANDED CLAY SECTIONS WERE INFLUENCED MORE BY THE PERCENTAGE OF COARSE EXPANDED CLAY AGGREGATE THAN BY THE ASPHALT CONTENT. SKID NUMBERS SHOW A CONTINUOUS RISE WITH WEAR AS MEASURED AT O, 4, 8 AND 12 MONTH PERIODS. THE AVERAGE SKID NUMBER ROSE FROM 45 TO 57 FOR EXPANDED CLAY MIXTURES WHEREAS THE CONTROL SECTIONS ROSE FROM 35 TO 47 IN THE SAME PERIOD. /AUTHOR/

  • Record URL:
  • Supplemental Notes:
    • Hpr-1(6), NO 5, STATE RES PROJ NO 65-3B
  • Corporate Authors:

    Louisiana Department of Highways

    P.O. Box 44245, Capitol Station
    Baton Rouge, LA  United States  70804

    Bureau of Public Roads /US

    400 7th Street, SW
    Washington, DC  United States  20590
  • Authors:
    • Arena, P J
  • Publication Date: 1969-4

Subject/Index Terms

Filing Info

  • Accession Number: 00210420
  • Record Type: Publication
  • Source Agency: Bureau of Public Roads /US
  • Files: TRIS, STATEDOT
  • Created Date: Oct 27 1994 12:00AM