This research represents a laboratory study of the effect of the aggregate shape in HMA. The shape of
aggregates particles is not the only factor of aggregate characteristics which effect on HMA. Other
Parameters such as aggregate gradation and aggregate surface texture are also effect. The aggregate
shapes considered for the study were cubical, disk and blade shapes. Two aggregate surface textures used
in the mix which were smooth and rough particles. The aggregate gradations used in the mixtures were
maximum, medium and minimum gradation .Shape of aggregate was determined through two methods.
The first method was an image measurement of coarse aggregate while the second method was particle
shape index. Marshal tests and indirect tensile test were performed to investigate the different in
behaviors of different samples with different parameters considered in this study taking into account that
the control mix contains crushed gravel, rough aggregate particles with disk shape, medium gradation of
aggregate and 4% of limestone powder as mineral filler.
The results showed that using of cubical aggregate shape increased each of Marshall Stability, bulk
density, Marshall Stiffness, Marshall Quotient, Stiffness Modulus and the Indirect Tensile Strength
of the mix than disk and blade shapes while decreased each of flow and air voids. The results also,
showed that medium gradation of aggregate had good results than other gradations. By using rough
particles the values of ITS and stiffness modulus were higher than using smooth particles