Experimental Study on Gilsonite-Modified Asphalt

This paper presents an experimental study on investigating the properties of Alaskan asphalt binder modified with different percentages of gilsonite over a wide range of climatic conditions by addressing the performance grade (PG) of gilsonite-modified binders according to Superpave specifications. The base asphalt used in this study was the neat asphalt with PG 52-28, and 5 different percentages of gilsonite (0, 3%, 6%, 9%, and 12% of total binder content) were introduced. With the increase of gilsonite content from 0% to 12%, the PG high temperature increased from 52°C to 70°C. However, the PG low temperature also increased from –28°C to –22°C. The results indicated that the addition of gilsonite tends to improve the rutting resistance of asphalt binders, however, increases the tendency for fatigue cracking and low temperature cracking. Adding low content of gilsonite (i.e. 3% within the scope of this study), the modified binder presents improved rutting resistance without any compromise of resistance to low temperature cracking.