Comparing the Performance of Granular and Extracted Binder from Buton Rock Asphalt

Abstract

Buton Rock Asphalt (BRA) is natural rock asphalt found in Buton Island, Northwest Sulawesi, Indonesia. This study compares the performance of asphalt concrete made by two different methods of BRA binder preparation. The first method heats and crushes the rock into granular asphalt, while the second method extracts and recovers the bitumen out of the rock to produce pure BRA bitumen. Petroleum bitumen is used as a control. Rheological properties of pure BRA bitumen, a blend of petroleum bitumen, and pure BRA bitumen were determined. The properties of these binders were used to quantify the contribution of binder in resisting permanent deformation and fatigue cracking. Bituminous mixtures of different BRA binders and petroleum bitumen were prepared. Ordinary bitumen was added to the mixture of granular BRA to achieve the optimum bitumen content. It was found that BRA binders yield mixtures with better stiffness modulus, rate of permanent deformation, and creep stiffness compared to petroleum bitumen mixture. Mixtures with a higher percentage of granular BRA yield a better performance when compared to the mixture of pure BRA bitumen. It may be concluded that granular BRA would be the best alternative, provided that the transportation cost of the material from Buton Island can be competitive.