Evaluating the impact of vehicle overloading on the structural layers of road pavement (PDF)

Master's Thesis from the year 2023 in the subject Engineering - Civil Engineering, grade: 3.96/4, Mekelle University (Ethiopian institute of Technology Mekelle), course: Road and Transportation Engineering, language: English, abstract: Many researchers agree that the contribution of vehicle overloading in the degradation of road pavement over the environment and the aging of materials is significantly larger. As such, the thesis emphasized overloading vehicles, which is considered a major factor responsible for most pavement damage worldwide.

The thesis aimed to evaluate the effect of overloading on pavement layer deterioration and its effect on the life of the asset and the economic loss induced due to overloading. The input data for analysis were collected as a secondary source. Moreover, KENLAYER, part of the KENPAVE Computer Program, was applied for the pavement layers' nonlinear analysis and critical responses. The damage ratio indicating premature failure of the road is then determined from these critical responses and the actual reduction in service life of the road segment in years was determined. An economic evaluation criterion, the net present value was used to determine the economic loss for two scenarios, with and without overloading for the road investment.

The road segment under study was designed for a traffic of 1.651*10^6 ESAL. On the other side, from the actual traffic and axle load data analysis results, the actual on-road traffic was 3.02*10^6. Thus, the overloaded truck traffic has created an extra load on the road pavement. As a result, pavement structures were damaged in an unexpected situation.
The critical response results revealed that the tensile strain at the bottom of the asphalt layer and compressive strain at the top of the subgrade increased with increasing axle loads. Damage analysis was performed based on the Ethiopian Road Authority failure criterion, the permanent deformation on the top of the subgrade was the governing for the single axle with a single axle. In addition, the fatigue cracking on the bottom of the asphalt layer was the governing condition for single axles with dual wheels, tandem, and tridem axles.