Precisions of Flat and Elongated Particle Tests ASTM D4791 and VDG-40 Videograder

Abstract

The design procedures for Superpave and stone-matrix asphalt mixtures emphasize the importance of aggregate shape. The current test procedure for characterization of aggregate shape, ASTM D4791, lacks a precision statement and is extremely time-consuming. A round-robin analysis was conducted with 15 laboratories, five materials, and two replicates to determine a precision statement for ASTM D4791. The results from the round-robin analysis, and for two additional materials obtained by the current procedure, were compared with results from the VDG-40 videograder, a promising automated device for measurement of aggregate shape. Although a correlation was indicated, further research is needed to relate the measurements of aggregate shape obtained by both tests to hot-mix asphalt performance.

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