【正文】 workability, shear resistance, tensile strength, stiffness, fatigue response, and optimum binder content of the mixture [1]. The successful quantification of aggregate geometric irregularities is essential for understanding their effects on pavement performance and for selecting aggregates to produce pavements of adequate quality [2]. Aggregate morphological characteristics are very plex and cannot be characterized adequately by any single test. As a result, conflicting results have been reported on how aggregate shape influences the quality of HMA mixtures [39]. Due to their irregularity, the shape of aggregates is not accurately described by Euclidian geometry. Fractals are relatively new mathematical concept for describing the geometry of irregularly shaped objects in terms of frictional numbers rather than integer. The concept of fractals introduced by Mandelbrot [10], which has the shape formed in nature, has been usually analyzed using Euclidian geometry. The key parameter for fractal 1 analysis is the fractal dimension, which is a real noninteger number, differing from the more familiar Euclidean or topological dimension. The fractal dimension for a line of any shape varies between one and two, and for a surface between two and three. Fractaltheory uses the concept of fractal dimension, DR, as a way to describe the shape of aggregates. In recent years, fractal geometry techniques have found widespread applications in many disciplines, including medicine, biology, geography, meteorology, manufacturing, and material science. Relatively, there have been a few applications of fractal geometry in civil engineering. Some studies have been devoted to developing procedures to determine the particle fractal dimensions [1117]. Others have focused on the effect of fractal dimension of aggregate on engineering properties of soils [18, 19] and asphalt concrete [20, 21]. However, there is no prehensive study that investigated the effect of aggregate fractal dimension to the Marshall stability, flow, and Marshall Quotient (MQ). Consequently, the present study was undertaken to verify whether there is a relationship between the fractal dimension (DR) and the mechanical properties of asphalt concrete. 2. Materials and Methods The bitumen used was AC20 bitumen. Crushed Basalt was used as the aggregate material. A typical heavy traffic gradation for hot mix asphalts (HMA), designated as Type I in the Turkish State Highway Specifications, and was selected. The Marshall stability and flow tests were carried out following the procedure of the Test Method for Resistance of Plastic Flow of Bituminous Mixtures Using Marshall Apparatus in ASTM D1559. The imaging system used by the authors consists of a Nikon D80 Camera and Micro 60 mm objective manufactured by Nikon. ImageJ was used as the image analysis program. The other properties of used materials test procedures, imaging system and image processing steps were also detailed in Arasan et al. [22]. Additionally, fractal dimension of aggregates was calculated with areaperimeter method [16]. 3. Correlation between fractal di