Impact of Modified Axle Load Factors of Heavy-Duty Electric Trucks on Existing Highways

This study presents a framework to assess the impact of Modified Equivalent Axle Load Factors (EALFs) of heavy-duty Battery Electric Trucks (BETs) on existing highways. An as-built highway section from Montana, USA, from Long-Term Pavement Performance database was considered to demonstrate the framework. A three-dimensional finite element model was developed and validated against in-situ Falling Weight Deflectometer measurements. Viscoelastic asphalt concrete and stress-dependent unbound layers were considered to simulate the field responses. A tri-criteria mechanistic approach was adopted to compute the EALFs, based on three damage indicators: cumulative surface deflection, fatigue strain at the asphalt layer bottom, and rutting strain at the subgrade top. Loading configurations encompassing three tyre inflation pressures (550, 720, and 800 kPa) and three battery mass distribution ratios (70:30, 50:50, 30:70) between the steer and drive axles were investigated for BETs. The analysis confirmed that the Modified EALFs increased from 19.78 to 57.64 for Internal Combustion Engine Trucks (ICETs) and BETs, respectively, which demonstrates how the BETs would impact the existing pavements. Service-life projections suggested that full BET deployment would reduce design life by approximately 13% (a 5-year reduction) with the structural number required to increase from 6.7 to 7.0 to sustain the design traffic.