Published Online: 26 July 2007
Page Count: 7
Ph.D., P.E., Research Engineer, INDOT, Division of Research, West Lafayette, Indiana
Senior System Analyst, INDOT, Division of Research, West Lafayette, Indiana
Ph.D., PE, Transportation System Management Section Manager, INDOT, Division of Research, West Lafayette, Indiana
(Received 7 November 2006; accepted 10 June 2007)
This paper reviews the requirements established by the Indiana Department of Transportation for the properties of aggregate materials to avoid poor friction characteristics of the coarse aggregates and provide durable pavement friction performance. The focus is on the construction of the tables of the friction characteristics for the typical aggregates and the friction performance for the typical hot-mix asphalt (HMA) mixtures used in Indiana. Without traffic application, the aging of HMA materials may not cause enough changes in pavement friction. In order to better evaluate the friction characteristics of the aggregates, this paper introduces the decreasing rate of the British pendulum number, which provides more consistent evaluation of the friction durability. This paper divides the variations of pavement friction over time into three phases and shows the corresponding friction patterns. Open-graded friction course and stone mastic asphalt mix produce more consistent friction performance than SuperPave mix. For a certain mix, steel slag provides greater friction numbers than crushed gravel, crushed stone, and dolomite aggregates. For SuperPave 9.5-mm mix, crushed gravel provides more consistent friction properties than dolomite and crushed stone in the first year. However, they may become compatible with each other in friction properties later.
Paper ID: JTE100903