Journals Proceedings

Abstract

The dynamic modulus is a required parameter in the design and analysis of asphalt pavements. The dynamic modulus of asphalt mixtures increases with aging as the mixture becomes stiffer. This paper presents an experimental evaluation of dynamic modulus of asphalt concrete field cores in the State of Qatar where asphalt mixture is subjected to harsh weather condition of elevated temperature. A total number of six different pavement sections were selected to study the aging effect and mix design on the mechanical performance of asphalt pavements in Qatar. These six different sections were constructed by using different types of aggregates and different bitumen types. Field cores were extracted from these sites. The extracted field cores were sliced into base and wearing layers and dynamic modulus tests were performed on these specimens. The test results demonstrated that the effect of aging was more prominent in the wearing course of pavements as it is subjected to elevated temperatures compared to the base layer. Comparison of dynamic modulus master curves showed that the dynamic modulus of wearing asphalt mixture is higher in comparison to base mixture especially at high temperature-low frequency region. In addition, the results showed that asphalt mixtures prepared with modified binders showed higher dynamic modulus at high temperature-low frequency test condition in comparison to unmodified binders.