抄録
The objectives of this paper are to evaluate aggregate characteristics including elongation, flatness, and other shape indices. The following particle shapes were selected for this study: cubical, rod, disk, and blade. The change in rotation angle of coarse aggregate was found to correlate well with the internal resistance of a HMA mix. The particle index (PI) was shown to be an adequate measure of the combined contribution of particle shape, angularity, and surface texture to the stability of an aggregate. The PI value correlated well to aggregate geometric characteristics including elongation ratio, flatness ratio, shape factor, and sphericity. Cubical particles were desirable for increased aggregate internal friction and improved rutting resistance. The more cubical the aggregate, the higher the PI value. The PI value of coarse aggregate significantly affected the engineering properties of a HMA mix. The particle shape determined how aggregate was packed into a dense configuration and also determined the internal resistance of a mix. Of the four particle shapes evaluated, the cubical aggregate demonstrated the best rutting resistance. Flaky and/or elongated aggregate was shown to have lower compactibility and higher breakage.
