Fly ash impact on characteristics of asphalt mixtures

Abstract

The paper presents the results of testing of asphalt mixtures AB11s made with various percentages of fly ash, where the ash was used as a partial or complete substitute for stone filler. The paper presents the results of the testing of fly ash properties to determine their suitability for use in asphalt mixtures. The experimental research was performed on asphalt samples containing fly ash from three different sources, with the degree of stone filler substitution amounting to 25%, 50%, 75%, and 100%.  The control mixture was prepared with 100% of stone filler. The paper also presents the volumetric structure of tested asphalt mixtures. The results of this study indicate that a satisfactory volumetric structure can be achieved through adding fly ash, while the bulk density and voids of the mineral and asphalt mixture generally depend on the type of ash and its content. The stability and flow of mixtures with fly ash are favorable compared to the control mixture. With the increase of the percentage of fly ash, the asphalt mixture’s resistance to permanent deformation has also increased. The water sensitivity is generally lower in mixtures with ash compared to the control mixture, and depends on the type and percentage of ash in the mixture.