Because in the field asphalt concrete acoustic properties (i.e., velocities and corresponding attenuations) are unknown, a modified version of the non-collinear wave mixing method is proposed to evaluate oxidative aging levels. Longitudinal transducers mounted on angle wedges are employed to launch subsurface dilatational waves to allow evaluation when there is only access to one side of the asphalt concrete pavement. For the mixture used, one fixed incident angle was found, which is suitable for the range of oven-aged asphalt concrete specimens, i.e., 0–36 h. Theoretical explanation and experimental evidence supporting the validity of the proposed approach is presented.