Effects of mineral fillers on hot-mix asphalt laboratory-measured properties

Abstract

It is well recognized that mineral fillers play an important role in the properties of mastics and hot-mix asphalt (HMA) mixtures. Better understanding of the effects of fillers on the properties of mastics and HMA mixtures is crucial to good mix design and high performance of HMA mixtures. This paper presents a laboratory investigation into the effects of different fillers on some properties of asphalt mastics and HMA mixtures. Three filler types and four filler contents were used to obtain the master curves of mastics and to characterize the stiffening effect of filler in mastics. The effects of filler on the characteristics of HMA mixtures were also investigated. The properties of HMA mixtures evaluated include optimum asphalt cement (AC) content, indirect tensile (IDT) strength, toughness index (TI), tensile strength ratio (TSR) and asphalt pavement analyzer (APA) rut depth. The results suggested that fillers had significant influence on the properties of HMA mixtures. With the increase of filler content, some properties of HMA improved while others decreased. Filler content for mix design should be determined based on the overall performance of HMA mixtures.