Abstract:
The purpose of this study is to evaluate the effect of the Superpave aggregate gradation on Marshall Parameters. The Superpave Specifies aggregate gradation was
used to select aggregate gradation as such blending of available aggregate was carried out and that the gradations were above, through and below the Superpave restricted zone. The Marshall method was used to design the asphalt mixtures. Asphalt concrete mixes were designed for 28 numbers of Superpave aggregate gradations and were tested in the laboratory to evaluate their stability and flow value. In addition, density - void analysis was carried out to find Marshall Parameters.
Statistically, all type of mixes (over, through and above the restricted zone) did not
show any significant difference on Marshall Stability and Void in Mineral aggregate
(VMA) in this study. The gradation pass below the restricted zone, those mixes showed higher Va and lesser Flow value than the gradation pass above / through the
restricted zone.
Based on the testing perfonned In this study, following recommendations can be
made;
1. Superpave specifies aggregate gradation could be used as a guide to develop
100 percent crushed granite aggregate blends for wearing course.
2. Superpave coarser aggregate gradation (gradation that pass through or below
the Superpave restricted zone) could be used as wearing courses with local
conditions (still not use such a gradation for wearing coarse in Sri Lankan
specifications) .
