Gradation design and effect of the forta-fi fiber on the mechanical properties of SMA 12.5 mixture

Abstract

ABSTRACT

Rutting phenomenon is a real problem for the asphalt pavement of Vietnam due to important impacts of overloaded vehicles, especially in the hot and sunny conditions. Besides using the bitumen with higher levels of rutting resistance, modifying and improving the composition of the mixture such as aggregate gradation and binding content could be an altenative solution for this problem. Employing the Stone Mastic Asphalt (SMA) with discontinuous granulation is a suitable to this problem. Due to its special structure consisting of coarse aggregate and its higher percentage of binder, this material has proven its superiority in rutting and fatigue resistance throughout a wide rang of researches in the world. However, the SMA is not widely used yet in Vietnam. The first specification of design, construction and inspection for this kind of material has only been issued at the end of 2021. This paper aims at introducing an initial gradation design with some principal characteristics of the SMA mixture. The influence of the Forta-fi fiber to the mechanichal characteristics of SMA mixture is also investigated. According to the experience results, this additive
fiber permits to improve the Indirect tensile strength up to 21.9%.

Keywords: SMA; Stone Mastic Asphalt; Marshall stability; flow; bitum polymer; cellulos; Forta-fi; Indirect Tensile Strength