The purpose of this paper is to present a new, rational and effective model for estimating the modulus of asphalt concrete using binder modulus and volumetric composition. The model is based upon an exixting version of the law of mixtures, called the Hirsch model whic combine series and parallel elements of phases. Models are presented for both dynamic complex shear modulus and dynamic complex extensional modulus. Semi empirical equations are also presented for estimating phase angle in shear loading and in extensional loading. The proposed model was verified by comparing predicted modulus and phase angles to values reported in the literature for a range of mixtures