Evaluation of Fiber-Reinforced Asphalt Pavements : Laboratory Study

2016PDFTech ReportFHWA-ID-16-237RP 237UI-14-02Hot mix paving mixturesAsphalt pavementsPavement performancePaving materialsPolymer fibersFiber-Reinforced Asphalt Pavements (FRAP)mix designperformance evaluationAASHTOWare Pavement MEIdahoUnited StatesIdaho. Transportation Dept.Bayomy, FouadMuftah, AhmedWen, HaifangBahadori, AmirUniversity of Idaho. Dept. of Civil EngineeringIdaho. Transportation Dept. Research ProgramUnited States. Federal Highway AdministrationUS Transportation CollectionThe Idaho Transportation Department (ITD) initiated a field project to evaluate the effectiveness of using fibers to mitigate rutting and fatigue distresses at US-30 east of Montpelier in south Idaho. The project was constructed in August 2014 to address the observed excessive rutting and fatigue cracking. The constructed project is a 3.22-mile road stretch where 0.4 ft of the existing asphalt surface was milled and replaced by a new HMA overlay. The project length was divided into four sections that are approximately equal in length. Three sections were built with fiber-modified dense graded asphalt mixes. The fibers used were polyethylene blended with aramid fibers provided by Forta Fi Corporation; aramid fibers treated with wax (ACE fibers) provided by Surface-Tech, Inc., and glass fibers provided by Nycon Corporation. Fiber contents and methods of fiber addition were established and controlled by the vendors during field production. The fourth section was built with a conventional unmodified mix as a control section. The mix design included high RAP content (47%). All mixes had the same mix design with no alteration due to fiber addition. ITD intended to evaluate the long-term performance of the four pavement sections by monitoring the field performance over number of years. This report is about Phase 1 of the project and is limited the evaluation of the laid asphalt mixes using standard lab testing procedures. To perform the lab testing program, plant mix samples from the field were collected and used to prepare specimens in the lab for various lab characterization tests. In addition, cores were also collected to verify the mix design volumetrics and to conduct some other lab tests. Performance evaluation by laboratory tests included dynamic modulus, flow number, Asphalt Pavement Analyzer (APA), Hamburg Wheel Track, Indirect Tension (IDT), and Creep Compliance tests. Analysis of laboratory test results indicated that there is no significant difference in performance of rutting, fatigue and low temperature cracking among the four mixes. Performance evaluation using the AASHTOWare Pavement ME Design software revealed similar conclusions where predicted performance over a 20-year design life did not vary significantly among the four mixes. It is the authors\u2019 belief that the non-uniformity of the fiber dispersion in the mixes as observed during construction and the relatively small fiber contents recommended by the vendors could have contributed significantly to these results