Laboratory Performance Evaluation of Hot Mix Asphalt Mixture Using Belessa Kaolin as a Filler with Superpave Aggregate Gradation

Abstract

Mineral fllers and diferent aggregate gradations have a great efect on the mechanical property of asphalt concrete pavements. In this research, the efect of nonconventional material so-called Belessa kaolin and Superpave gradation on marshal properties, moisture susceptibilities, and permanent deformation in asphalt mixtures was investigated. Te chemical composition of Belessa kaolin shows that the total content of silicon dioxide (SiO2), iron oxide (Fe2O3), and aluminum oxide (Al2O3) was 63%, 24.1%, and 2.84%, respectively. Te physical properties of Belessa kaolin were conducted on specifc gravity, and the plastic index was 2.62 and 3.24, respectively. Based on the study area characteristics and temperature, a bitumen grade of 60/70 penetration is selected. Hot mix asphalt (HMA) specimens were prepared from three diferent Superpave gradations with conventional fller crushed stone dust (CSD) of diferent proportions (5.0, 6.0, and 7.0%) and fve diferent bitumen contents (4, 4.5, 5, 5.5 and 6%). A hot mix asphalt with 5.0% of CSD was selected as the control mix based on Ethiopian Road Authority (ERA) standard specifcations. Te conventional fller was replaced by Belessa kaolin at diferent replacement rates (0, 10, 20, 30, 40, and 50%) on the basis of the control mix with 5% CSD and 5.1% optimum bitumen content (OBC). Te replacement rate of 30% of Belessa kaolin provides better marshal properties and resistance to moisture susceptibility. Te results of the experiments indicated that the use of Belessa kaolin on HMA has fulflled the criteria specifed on the specifcation as a fller with Superpave aggregate gradation up to 30% replacement of conventional fller in HMA.