Factors Controlling Maximum and Minimum Densities of Sands

MAXIMUM AND MINIMUM DENSITY TESTS, CONDUCTED ON A VARIETY OF CLEAN SANDS, SHOW THAT THE MINIMUM AND MAXIMUM VOID-RATIO LIMITS ARE CONTROLLED PRIMARILY BY PARTICLE SHAPE, PARTICLE SIZE RANGE, AND VARIANCES IN THE GRADATIONAL-CURVE SHAPE, AND THAT THE EFFECT OF PARTICLE SIZE IS NEGLIGIBLE. CURVES WERE DEVELOPED FOR ESTIMATING MINIMUM AND MAXIMUM VOID RATIOS FROM GRADATIONAL AND PARTICLE-SHAPE PARAMETERS. ESTIMATES FOR SEVERAL NATURAL AND COMMERCIALLY GRADED SANDS AGREE WELL WITH MINIMUM AND MAXIMUM VOID RATIOS MEASURED IN THE LABORATORY. MINIMUM DENSITIES (MAXIMUM VOID RATIOS) WERE DETERMINED BY THE STANDARD AMERICAN SOCIETY FOR TESTING AND MATERIALS (ASTM) MINIMUM DENSITY TEST METHOD (TEST FOR RELATIVE DENSITY OF COHESIONLESS SOILS (D 2049-69)), EXCEPT THAT SMALLER MOLDS WERE USED. MAXIMUM DENSITIES (MINIMUM VOID RATIOS) WERE DETERMINED BY REPEATED STRAINING IN SIMPLE SHEAR, A METHOD WHICH HAS BEEN SHOWN TO GIVE GREATER DENSITIES THAN STANDARD VIBRATORY METHODS. /AUTHOR/