Effects of Asphalt-Mixture Characteristics and Vehicle Speed on Fuel-Consumption Excess Using Finite-Element Modeling

Abstract

The effects of pavement type on fuel consumption have received considerable attention in recent years, yet the influence of asphalt mixes characteristics and vehicle speed on fuel consumption excess has not been evaluated. This paper evaluates the effects of asphalt concrete (AC) characteristics and vehicle speed on fuel consumption excess using a three-dimensional (3D) finite-element (FE) approach. Finite-element modeling is used to simulate three flexible pavements typically used for low, medium, and high traffic volume. The effects of AC mixes with different binders and varying percentages (0, 15, and 40%) of reclaimed asphalt pavement (RAP) on fuel consumption excess are evaluated. The FE models are validated based on field stress and strain measurements obtained from the Louisiana Accelerated Loading Facility (ALF). Energy dissipation is calculated for the whole FE model due to materials’ viscous properties and is used as an input in fuel consumption estimation. Results indicate that fuel consumption due to energy dissipation constitutes only a very small fraction of the total vehicle fuel consumption. Nevertheless, pavements with the stiffer mix, i.e., the mixes with high percentage of RAP, consume less energy. Therefore fuel savings can be expected when increasing the stiffness of AC layers using RAP materials. Fuel consumption excess is lowest at the highest speed and increases with decreasing speed. The fuel consumption excess is higher for pavements with greater thickness of the AC layer, indicating a noticeable impact of AC thickness on fuel consumption excess.