Thermal Properties of Asphalt Pavements Modified with a Lightweight Silica-Based Composite

Abstract

Pavements are exposed to different external factors such as traffic loading, levels of moisture, and ambient temperature fluctuations. External temperature change affects the pavement’s temperature profile and therefore its behavior. Previous research states that the pavement’s surface temperature cannot be addressed by adjusting its thermal properties because it primarily relies on the color of the surface. Furthermore, the temperature gradients in the pavement’s temperature profile can be associated with thermal cracking, which is an aspect that has not been fully investigated. The objective of this article is to analyze the temperature profile of a modified asphalt pavement and its effects on the thermal gradients in different seasons. Consequently, the thermal properties of a modified asphalt pavement with a novel silica-based composite, developed at Arizona State University (ASU), called “aMBx” were calculated. Three types of mixtures were considered in this study: Control (0% aMBx), 10% aMBx, and 30% aMBx contents by weight of asphalt binder in the mixture. Moreover, slabs of 7.5 cm and 15 cm in thickness were built to monitor the thermal behavior in the field using wireless thermocouples, where the temperature was monitored and recorded for one year. In addition, a pavement temperature model was implemented using validated software developed at ASU. The full pavement temperature profile was simulated for the three types of asphalt mixtures discussed in this study. The results showed that the pavement surface temperature can be managed by changing the thermal properties, which, in this case, was driven by the materials and thickness of the materials. The temperature gradient was lower for the aMBx-modified pavements. Therefore, it was concluded that aMBx-modified asphalt pavements may lead to lower thermal susceptibility.