Effects of Forta-fi Fiber on the Resistance to Fatigue of Conventional Asphalt Mixtures

摘要

In order to deal with the issues of rutting in Vietnam, asphalt mixtures have been highly modified using a variety of additives, e.g. SBS, Polyethylene, crumb rubber or even produced with less bitumen so as to improve its resistance to permanent deformation. As a result, the flexibility of modified asphalt mixtures much decreases compared to unmodified mixtures, giving rise to a reduction in the resistance to fatigue cracking. Moreover, the thickness of flexible pavement structures in Vietnam is typically small ranging from 12 to 15 cm in asphalt layers while overloaded vehicles cannot be effectively controlled. Consequently, fatigue cracking occurs more and more often and early after opening to traffic. This paper aims at evaluating the effectiveness of Forta-fi fiber in improving the resistance to fatigue of conventional asphalt mixtures produced with low bitumen content and a very coarse dense gradation. Marshall method was used for sample compaction and mix design, whereas cyclic indirect tensile test was used for fatigue characterization. The experimental results show that adding 0.1% of Forta-fi fiber to asphalt mixtures significantly improves its resistance to fatigue, up to 2 times higher.