Comparative evaluation of dynamic responses of RCC composite pavement under different moving axles

Abstract

Roller-compacted composite pavement is considered as an alternative for traditional pavements that provides the desired benefits of both rigid and flexible pavements in a cost-effective manner. To evaluate the performance of roller-compacted concrete (RCC) composite pavement under moving loads, a three-dimensional finite element model (FEM) was developed. A realistic dynamic moving load was applied to the surface of the pavement via DLOAD subroutines developed by FORTRAN. The dynamic response of the pavement at critical locations induced by single, tandem, and tridem axles at speeds of 8 and 80 km/h was determined using the developed FEM model and utilized to estimate pavement performance. Sensitivity analysis of design factors considering variations of hot mix asphalt (HMA) and RCC thicknesses, RCC elastic modulus, axle configurations, and moving speed was conducted to evaluate their impact on fatigue life and rutting development of RCC composite pavement. The results show that the performance of the pavement is significantly affected by axle configurations and moving speed. Among different axle configurations, the tandem axle creates the highest tensile stress and shear stress in the RCC base and HMA layer, respectively. The fatigue life of the pavement prolongs by increasing in the speed of moving loads, so it is expected that the pavement withstands higher load repetition when it is subjected to higher speed traffic. Moreover, increasing layer thicknesses and stiffness of the RCC layer improve fatigue life and rutting performance of the pavement. Even though increasing the thickness of the HMA layer enhances the fatigue life of pavement, increasing it to over 15 cm increases the potential of rutting.