Performance Comparison between Fiber-Reinforced and Rubber-Modified Asphalt

This paper presents the performance and evaluation of fiber-reinforced asphalt concrete (FRA) in comparison with the rubber modified asphalt (RMA) through laboratory experiments and field observations. Rubber/polymer is believed to enhance the binding properties of the asphalt pavements to increase their engineering characteristics. Some of researchers and highway agencies in the cold regions have considered to add fibers in the currently used RMA to produce fiber-reinforced rubber-modified asphalt concrete (FRMA) to improve its resistance to low temperature cracking and reflective cracking. However, due to the recent cost increase of polymer/rubber material, the possibility of replacing RMA with FRA is being proposed. Thus, it is important to research and investigate the performance between the FRA and RMA. A fiber reinforced asphalt overlay project was constructed on S. Knoles Drive near the Applied Research and Development (ARD) Building at Northern Arizona University. The overlay project (429’Length x 16.75’ Width) was conducted with two types of asphalt mixtures including RMA and FRA to be placed adjacent to each travel lane of the road. Because fiber reinforced asphalt mix has never been used in roadway design and construction in Northern Arizona, it is of interest to understand its resistance to freezing-thawing effect, fatigue cracking, and low temperature cracking. A material testing is undergoing to investigate the performance of FRA pavements in comparison with the currently used RMA pavements so as to provide better understanding of the role played by the fiber in improving the performance of conventional asphalt pavements. Asphalt samples from both asphalt mixtures were collected at the back of a paver from both lances at the time of laydown. These samples were used in the following lab tests: freeze-thaw cycle durability test, and low temperature cracking resistance test using a bending beam rheometer (BBR). The results from the lab tests help generate predictions of low-temperature performance of the two types of asphalt pavement. Field inspections have been scheduled to assess pavement surface conditions. By combing the lab test results with field assessments, the paper provides an analysis to help with decision making in whether it is appropriate to replace currently used RMA pavements with FRA pavements.