Mechanical Response of Modified Asphalt Pavements

In this work, pavement cross-section as stipulated by the Indian Roads Congress code of practice for pavement design was used in the stress-analysis. Typically, two types of asphalt layers are laid over three to four layers of granular materials for pavements constructed for heavy traffic volume in India. Asphalt mixtures pertaining to these top two layers were fabricated with polymer modified and unmodified asphalts in the laboratory. These mixes were tested in the simple performance test equipment at temperature of 60 °C under a wide range of frequencies. A four parameter Burgers' model was used for fitting the experimental data for both the asphalt layers. A two-dimensional finite element model of the pavement structure was used within the ABAQUS computing environment. The granular base, subbase and subgrade granular layers were assumed to be elastic. The pavement model was subjected to cycles of periodic loading and the stresses and strains were monitored at all the critical locations. This was used to quantify the influence of modifiers on the mechanical response of the pavement and parametric analysis was carried out to find out enhanced service life of the asphalt layers that could be achieved due to the use of high-performance materials.