AN EVALUATION OF THE BULK SPECIFIC GRAVITY FOR GRANULAR MATERIALS

Abstract

ACCURATE DETERMINATION OF BULK SPECIFIC GRAVITY OF AGGREGATES IS OF PAVAMOUNT IMPORTANCE FOR SUCCESSFUL DESIGN OF BITUMINOUS PAVING MIXTURES AS WELL AS PORTLAND CEMENT CONCRETE. THE COMPLICATING ELEMENT IN SPECIFIC GRAVITY DETERMINATION IS THE ACHIEVEMENT OF SATURATED SURFACE-DRY CONDITIONS. THE VARIOUS MODIFICATIONS SUGGESTED BY SEVERAL INVESTIGATORS EITHER OFFER LITTLE IMPROVEMENT OR ARE TOO ELABORATE TO BE OF PRACTICAL VALUE IN THE FIELD OR COMMON LABORATORY. IN THIS STUDY, THE BULK SPECIFIC GRAVITIES OF CRUSHED AGGREGATES AND CYLINDRICAL ROCK CORES FROM SIX LIMESTONE QUARRIES, ONE SLAG, ONE CRUSHED TRAP ROCK, AND ONE SYNTHETIC AGGREGATE (SYNOPAL) WERE DETERMINED BY FIVE METHODS. THE METHODS ARE STANDARD ASTM, GEOMETRICAL MEASUREMENT, MERCURY DISPLACEMENT, AND TWO CHEMICAL INDICATOR METHODS PROPOSED BY THE AUTHORS. THE RESULTS BY THE STANDARD ASTM METHODS, IN TERMS OF REASONABLENESS AND REPEATABILITY, ARE COMPARED AND EVALUATED IN RELATION TO RESULTS BY THE OTHER FOUR METHODS. THE PROCEDURES OF THE PROPOSED CHEMICAL INDICATOR METHODS (COBALT CHLORIDE AND FLUORESCEIN SODIUM SALT) ARE DESCRIBED. THE REPEATABILITY AND REPRODUCIBILITY OF THE COBALT CHLORIDE INDICATOR METHOD ARE PRESENTED. /AUTHOR/