Evaluation of Particle Shape and Texture of Mineral Aggregates and Their Blends

摘要

Two important factors for minimizing rutting of hot mix asphalt (HMA) mixturesare: (1) the fractured face count of aggregate when gravel is used as coarse aggregate, and (2) the use of manufactured sand. Both these factors relate to the shape and texture of the aggregate particles. One of the objectives of this paper was to study the effect of crushed particle count on the particle shape and texture index (ASTM D3398) of gravel coarse aggregate and to determine if there is an upper limit on the crushed face count above which the particle shape and texture index of the coarse aggregate fraction would not increase significantly. A definite relationship was found to exist between the crushed face count and index of particle shape and texture of the coarse aggregate. Higher percentages of crushed particles increase the index of particle shape and texture significantly. Highway agencies also limit the amount of natural sand in HMA mixes. This is usually done by generically specifying the maximum allowable percentage of natural sand.