MAXIMUM DENSITY DETERMINATION OF SUBBASE MATERIALS, MAY 1970

THE OBJECT OF THIS STUDY WAS TO ESTABLISH A SATISFACTORY TEST METHOD OF DETERMINING THE MAXIMUM DENSITY OF COHESIONLESS MATERIALS, SUCH AS SUBBASE, THAT WOULD PROVIDE COMPACTION CRITERIA FOR THESE MATERIALS AND BE COMPACTIBLE WITH CURRENT METHODS OF DENSITY DETERMINATIONS IN THE FIELD. IN ORDER TO ESTABLISH A TEST PROCEDURE FOR DETERMINING THE MAXIMUM DENSITY OF A SUBBASE MATERIAL, THREE DIFFERENT TEST METHODS WERE UTILIZED: THE STANDARD PROCTOR METHOD (AASHO T- 99, MEHHOD C) USING 4- AND 6-INCH CYLINDRICAL MOLDS, A VIBRATING TABLE TYPE OF COMPACTIVE EFFORT (ASTM D-2049) USING 6- AND 11-INCH CYLINDRICAL MOLDS, AND A RECTANGULAR MOLD VIBRATED FROM THE SURFACE. THE EFFECTS OF SUBBASE GRADATION, MOISTURE CONTENT, AMPLITUDE, SURCHARGE PRESSURE, AND VIBRATION TIME WERE INVESTIGATED AND ANALYZED. THREE TYPES OF SUBBASE MATERIALS - GRAVEL, LIMESTONE AND SLAG - WERE EMPLOYED TO EXAMINE THE EFFECTS OF SUBBASE TYPE ON MAXIMUM DENSITY. IT WAS FOUND THAT THE STANDARD PROCTOR TESTS CONSISTENTLY PRODUCED HIGHER DENSITIES THAN THE VIBRATORY MEHODS. MOREOVER THE STANDARD PROCTOR TEST UTILIZING THE 6-INCH CYLINDRICAL MOLD YIELDED DENSITIES THAT WERE APPROXIMATLY 2.8 PCF HIGHER THAN THOSE OBTAINED WITH A 4-INCH. A HIGH DEGREE OF CORRELATION WAS FOUND BETWEEN THE STANDARD PROCTOR METHOD (6-INCH MOLD) AND ASTM VIBRATORY METHOD, IN WHICH THE MATERIALS WERE VIBRATED AT 0.030-INCH AMPLITUDE AT A SURCHARGE PRESSURE OF 1 PSI. AN ESTIMATING EQUATION, RESTRICTED TO THE SUBBASE MATERIALS AND TEST CONDITIONS INVESTIGATED, WAS DEVELOPED FOR PREDICTING MAXIMUM DENSITIES FROM THE VIBRATORY TEST DATA. THE EQUATION MAY BE USED IN PLACE OF THE STANDARD PROCTOR COMPACTION METHOD. /AUTHOR/

Subject/Index Terms

Filing Info

  • Accession Number: 00230725
  • Record Type: Publication
  • Source Agency: Federal Highway Administration
  • Files: TRIS, USDOT, STATEDOT
  • Created Date: Apr 1 1971 12:00AM