Tests for Evaluating Fine Aggregate Particle Shape, Angularity, and Surface Texture

Abstract

Particle shape, angularity, and surface texture are critical properties in assessing fine aggregate quality for asphalt concrete. The index for aggregate particle shape and texture and uncompacted voids tests indirectly measure these properties. Several sources of fine aggregate from Alabama were evaluated by both tests. Modifications to current test procedures to include all particle sizes normally included in fine aggregate are suggested. Particle index and uncompacted voids are affected by gradation, and this effect should be eliminated in assessing fine aggregate quality. Testing of individual size fractions and computation of composite indexes or void contents or testing of samples with standard gradations are viable options for elimination of gradation effects. Particle indexes or uncompacted voids of blends of two aggregates may be assessed by linear proportioning of values for individual components.