In this article a new methodology is presented for the mechanical characterization of the asphalt mixes, specially the recycled asphalt mixes, which leads to define the adequate laboratory tests and to formulate a new constitutive model able to integrate the mechanical properties and reproduce the response of the material in a more complex context. The addition of asphaltic recycled material over a conventional mix, change in a significant way the properties of this mix. The design of recycled asphalt mixes requires additional information far away the properties of this mix. The design of recycled asphalt mixes requires additional information far away from the usual test used in the design of conventional mixes, to pick up the evolution of the tenacity of the cracking resistance, determinant variables in the recycled asphalt mixs behavior. For thid purpose, the direct tensile test in proposed as the experimental reference for the characterization of the material. A new constitutive model in formulated considering in a explicit shape, the influence of the strain shape, the influence of the strain rate of the material in the simulation of its response. The direct tensile test is used to calibrate the parameters of the model, and so characterize its structural response. The main objective of this development is the simulation of the behavior of the recycled asphalt mixture in a fleexible pavement. The results obtained reach a good approximation to the experimental measures with the proposed model.