Evaluation of Test Equipment for Determination of Fine Aggregate Specific Gravity and Absorption

Abstract

Concern has been expressed about the repeatability of the current AASHTO T 84 method for determination of fine aggregate specific gravity. Two new methods are available for determining bulk specific gravity and absorption of fine aggregates: the AggPlus system using the CoreLok device and the SSDetect system. In addition, a new automated Langley de-airing device is available for AASHTO T 84. The objectives of this study were (a) to evaluate the reproducibility of SSDetect, CoreLok, AASHTO T 84, and AASHTO T 84 with the Langley de-airing device and (b) to determine if either of the new systems would produce results statistically similar to those produced by the current AASHTO T 84 procedure. The AASHTO procedure, when used with the Langley de-airing device, gave similar results to AASHTO T 84 but with reduced variability. The SSDetect procedure produced the highest bulk specific gravity and lowest percent absorption followed by the CoreLok and AASHTO T 84 procedures. There was no significant difference in apparent specific gravity values. Increasing the cure time for the SSDetect procedure resulted in increased saturated surface dry mass.

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