Axle Overloading and High Tire Pressure Effects on Flexible Pavements

Axle overloading and high tire pressures on the highways and motorways in Pakistan are some of the reasons that cause early pavement deterioration. This study aims to illustrate the effect of axle overloading and high tire pressure on the flexible pavement structure and derive the truck factors for trucks to quantify the damage to the pavement due to a single pass of 2-axle, 3-axle, 4-axle, 5-axle, and 6-axle truck using the results reported in the Pilot Axle Load Survey at N-5 conducted by the National Transport Research Centre in 2017. To determine the effect of axle overloading and high tire pressure, a theoretical linear elastic mechanistic-empirical analysis for four-axle configurations was performed using KENLAYER (KENPAVE) and eight regression models were developed to find the Equivalent Axle Load Factor (EALFs) for two pavement distress criteria; the tensile strain at the bottom of asphalt layer (fatigue cracking), and the compressive strain at top of the subgrade (permanent deformation).