Structural and Economical Effect of Over Weight Trucks on Asphalt Pavement

Abstract

The general authority of road, bridges, and land transportation (GARBLT) specify the limitation of truck loads that run on Egyptian highways. Many trucks violate these limits by loading additional weights to decrease the transportation unit cost. This behavior causes severe deterioration to the pavement. Such violating trucks are charged by eventually little penalties compared to the damage they cause to the pavement. The objectives of this study is to evaluate the effect of increasing axle load, due to overloaded trucks, on the pavement life and to estimate a critical load that makes a boundary between penalized loads and the unallowable loads by developing a relationship between the number of load repetition to failure and axle load. The research used the KENPAVE software to calculate the horizontal tensile strain occurring at the bottom of the asphalt layer and the vertical compressive strains occurring at the top the subgrade soil due to the different axle loads. The calculated strains are then utilized to estimate the number of load repetitions to failure due to fatigue cracking using the Asphalt Institute (AI) method. Finally, relationships relating the predicted numbers of load repetitions with axle load and tire pressure were developed using regression analysis. In this study, Cairo-Alexandria desert highway was used as a case study.