PERFORMANCE EVALUATION OF HOT-MIX ASPHALT MIXTURE USING BELESSA KAOLIN AS A FILLER WITH SUPERPAVE AGGREGATE GRADATION.

Abstract

Filler, as one of the components in asphalt mixtures, plays an effective role in their properties and behavior, especially regarding binding and aggregate interlocking effects. Mineral fillers and different aggregate gradation have a great effect on the mechanical property of asphalt concrete pavements. One of the main problems in the construction of asphalt paving mixture is obtaining a sufficient amount of qualified filler material. To overcome this problem it is important to come across alternative filler material that can address this gap which is easily available. The effects of different minerals are introduced on the performance of hot mix asphalt. However, the influence of Belessa Kaolin on the performance of HMA mixture with Superpave aggregate gradation are not properly established. This research is conducted by using laboratory experimental research design and Non-Probability sampling techniques adopted. In this research, the effect of non conventional material so called Belessa kaolin and superpave gradation on marshal Properties, moisture susceptibilities and permanent deformation in asphalt mixtures was investigated. The chemical composition of Belessa kaolin shows that the total content of Silicon Dioxide (SiO2), Iron Oxide (Fe2O3) and Aluminum Oxide (Al2O3) was 65%, 24.1% and 1.84% respectively. The physical properties of Belessa kaolin was conducted on specific gravity and Plastic Index were 2.62 and 3.24 respectively. Both the physical and chemical properties were address the requirements according to ASTM C-618. Based on the study area characteristics bitumen grade of 60/70 penetration is selected. HMA specimens were prepared from three different Superpave gradation with conventional filler Crushed Stone Dust (CSD) of different proportion (5.0%, 6.0%, and 7.0%) and five different bitumen content (4%, 4.5%, 5% 5.5% and 6%). A hot mix asphalt with 5.0% of CSD were selected as control mix based ERA specifications. The conventional filler was replaced by Belessa kaolin at different replacement rate (0%, 10%, 20%, 30%, 40% and 50%) on the basis of control mix with 5% CSD and 5.1% OBC. Marshal properties and moisture susceptibility were performed to determine the optimum replacement rate of Belessa kaolin. The replacement rate of 30% of Belessa kaolin provide better marshal properties and resistance to moisture susceptibility. This study also investigated the rutting resistance characteristics of HMA with optimum Belessa kaolin and control mix. The results of the experiments indicated that the use Belessa kaolin on HMA has fulfilled the criteria specified on the specification