Research Pays Off: Reclaimed Asphalt Pavement with Steel Slag Aggregate: Successful Use in Illinois Pavements
Reclaimed asphalt pavement (RAP) consists of reprocessed HMA pavement material, such as asphalt and aggregates. RAP often contains high-quality, well-graded aggregates that are coated with asphalt cement but may include steel slag, a by-product of steel making.
Steel slag, however, may contain free lime and magnesia, which can react with water and cause the slag to expand.
To address the issue, the Illinois Center for Transportation took on a project to determine the expansive properties for RAP materials, especially those including recycled steel slag aggregates that could be used as pavement base materials in Illinois.
A clear conclusion from the research was that RAP materials with slag aggregate that was partly coated with asphalt had much lower tendencies to expand than the virgin steel slag aggregates, which showed high expansion potentials.
Before this research, steel slag RAP not used within 2 years was consigned to land fill. Blending steel slag RAP with the other RAP allows the entire HMA pavement to be milled together.
This Summary Last Modified On: 3/30/2014