MECHANISTIC ANALYSIS AND ECONOMIC BENEFITS OF FIBER-REINFORCED ASPHALT MIXTURES

Fatigue cracking and permanent deformation (rutting) are major distresses that occur in flexible pavements. Four-point bending beam as well as flow number laboratory tests have been used for several decades to evaluate the long-term fatigue and rutting resistance for asphalt mixture, respectively. One of the most significant solutions to prolong the fatigue life and improve rutting resistance for an asphaltic mixture is to utilize flexible materials such as fibers. In 2008 a laboratory testing program was performed on a conventional and fiber-reinforced mixtures to investigate the impact of added fibers on the mechanical, mechanistic, and economical attributes of asphaltic mixtures. Strain controlled fatigue tests were also conducted in that testing program according to American Association of State Highway and Transportation Officials (AASHTO) procedures. The results from the beam fatigue tests indicated that the fiber-reinforced mixtures would have much longer fatigue and rutting resistance life compared with the reference (conventional) mixtures. Additionally, a mechanistic analysis using 3D-Move software coupled with a cost-effectiveness analysis study based on the fatigue and rutting resistance performance on the two mixtures was performed for both newly constructed and overlay pavement structures. Overall, the analysis showed that fiber-reinforced asphalt mixtures exhibited significantly lower cost of pavement per 1000 cycles of fatigue and rutting lives per mile compared to conventional HMA mixture