Utilization of Buton Natural Rock Asphalt as Additive of Bitumen Binder in Hot Mix Asphalt Mixtures

Abstract

In Buton Island, an island located in South-East Sulawesi Island in Indonesia is found about 700 million tons natural rock asphalt (NRA) which have not been maximally utilized yet. Buton-NRA contains 20 to 30% of bitumen. This paper reported the first part of the research on utilizing of Buton-NRA as additive of bitumen binder in hot mix asphalt (HMA) mixtures. Amount of 15, 20, 25, 30, 35, 50, and 65% of very fine of Buton-NRA was added into the bitumen, resulted Buton-NRA-Bitumens binder. Penetration and softening point test was conducted to get penetration index (PI) value, an index to determine the temperature susceptibility of the binder. The results show that the Buton-NRA-Bitumens binder has low temperature susceptibility. Use as binder in HMA mixtures also shown that the Buton-NRA-Bitumens binder can improve the performance of the mixtures. Marshall Stability and stiffness of the mixtures is higher compare to that of base bitumen binder, especially Buton-NRA-Bitumens binder with 50% of Buton-NRA, Marshall Stability reach 2374kg and stiffness 311kg.mm, while HMA mixtures with base bitumen (0% Buton-NRA) only has 1294kg of Marshall stability and 169kg/mm of stiffness.