Current ICT Project
Investigators:
  E. Tutumluer (Primary), J. Popovics
Project Title:
  Expansive Characteristics of Reclaimed Asphalt
Start Date: 2/1/2007
End Date: 4/30/2009
Summary of Project:
  Reclaimed asphalt pavement (RAP) is the reprocessed hot mix asphalt (HMA) pavement material containing asphalt and aggregates. A viable solution for deposing of large quantities of RAP is to incorporate them into base and subbase applications for highway construction. However, RAP materials may contain an expansive aggregate such as steel slag that is not allowed in Illinois for use in the pavement substructure layers. Steel slag aggregates are particularly useful in areas where high frictional properties are required, such as HMA surface courses, yet, they may contain free lime and magnesia that may cause the slag to be expansive when reacted with water.
Objective of Project:
  The main objective in this project is to determine the expansive properties for reclaimed asphalt pavement (RAP) that may be used as pavement base materials in Illinois. Additional objectives will be to determine a test method for the expansion of RAP aggregate, the maximum acceptable level of expansion for different RAP aggregate types, properties and blending proportions with virgin aggregates, and the effects that RAP materials may have on pavement performance.
Expected Outcome:
  Processed RAP consists of high quality, well-graded aggregates coated by asphalt cement. Currently, the use of RAP is not allowed in the pavement substructure layers according to Illinois Department of Transportation (IDOT) specifications. Whether or not this is a major concern for Illinois will need to be studied by first successfully identifying the expansive nature of RAP sources statewide and secondly by establishing guidelines for blending recycled and virgin aggregates for the pavement substructure use. This research project is therefore aimed at such an evaluation of steel slag commonly found in reclaimed asphalt pavement materials in Illinois.
Click here to check the status of this project.
Last Updated: 11/18/2009