Flexible Pavement Damage Quantification for Heavy-Duty Electric Trucks

Abstract: The transition towards freight electrification and the growing charging infrastructure network are set to become key strategies in decarbonizing the transportation sector. However, transportation agencies worldwide remain uncertain about ensuring that current road systems have the capacity to meet the demands of heavy-duty electric vehicles (HDEV). These trucks, with their increased axle loads—largely owed to the location of heavy batteries—and higher torque, introduce loading scenarios that could adversely impact pavement service life through mechanisms not captured by conventional design approaches. This study proposes a generalized approach to quantify the combined damage induced by HDEVs on asphalt concrete pavements, especially at near-surface. The approach not only provides a weighted combination of distress mechanisms into one metric, but also establishes a full-truck damage representation through an effective number of repetitions to failure that enables a full truck comparison of an HDEV with the reference internal combustion engine vehicle (ICEV).
The starting point of the generalized approach is a two-pronged finite element model to establish three-dimensional contact stresses and quantify pavement stresses, strains, and deflections. The model includes: (i) three potential battery locations on the semi-truck cab, which led to load redistribution along the truck axles, relative to an ICEV reference case, coupled with varying acceleration levels; and (ii) pavement structures strategically selected to represent various functional classes in the State of Illinois: interstate, arterial, and rural roads.
As anticipated, increased axle loads invoked higher pavement responses throughout the structure. Conversely, higher acceleration rates predominantly affected near-surface responses, such as the longitudinal shear strain (along the traveling direction and direct component from in-plane shear). Following the mechanistic-empirical pavement design guide, transfer functions were applied to quantify various distresses, including bottom-up cracking, top-down cracking, shoving, and rutting. The combination of the various distresses indicated that while higher loads led to a faster rate of failure, acceleration independently influenced near-surface damage, which also depended on the pavement structure in consideration.
By investigating the impact of HDEV load magnitude and acceleration effects, this study provides a preliminary understanding of HDEV’s impact on flexible pavements with the overarching goals of withstanding the forecasted increasing presence of heavy-duty electric vehicles and developing more resilient pavements. The proposed generalized approach may be applied to other loading conditions (e.g., autonomous and connected platooning) and has the potential to be implemented as a modification to existing pavement design frameworks.