Quantification of Truck Electrification Damage to Flexible Pavements

Abstract

The transition to electrified freight transport is poised to introduce heavier axle loads because of the placement of battery packs and higher torque that is instantaneously available from the electric motor design. The current road infrastructure may not be equipped to meet such technologically driven demands, further straining the already deteriorating road network. This study quantifies the impact of heavy-duty electric vehicles (HDEVs) on the structural and near-surface behavior of flexible pavements. Three-dimensional finite element models of a truck tire, loaded on typical interstate, arterial, rural, and state pavement sections in Illinois, U.S., were analyzed. The resulting strains served as inputs into mechanistic-empirical transfer functions, and a cumulative damage framework is proposed. A parametric assessment of the combined impact of battery placement configuration and slip ratio (acceleration) evidenced two clear trends: 1) axle load redistribution because of battery-placement-influenced tensile, shear and compressive strains throughout the depth, accelerating bottom-up and top-down cracking, and rutting, and 2) higher acceleration-affected near-surface shear strains, driving shoving and shear-driven top-down cracking as the critical distresses. The Electric Truck Adjustment (ETA) index is introduced to evaluate relative pavement damage induced by different HDEV battery placement scenarios and acceleration with respect to internal combustion engine trucks. A step-by-step implementation scheme to embed the ETA framework into pavement design guidelines is detailed. Using the ETA parameter, optimum HDEV configurations reduced predicted service life by up to 30% for a typical interstate, rural, and state road, and up to 47% for arterial roads.