An investigation into the viability of using recycled asphalt pavement (RAP) as a more sustainable option for road maintenance treatments. This research paved the way for the development of new standards to allow RAP to be used for road maintenance in Pennsylvania.

Author(s): Shervin Jahangirnejad, Ph.D., P.E.
Venue: TRB
Date: 2019
Keywords: RAP, Bituminous Seal Coat
Client: PennDOT


The Pennsylvania Department of Transportation (PennDOT) has developed a process for using recycled asphalt pavement (RAP) as chip seal aggregates for low volume roads. The focus of the current effort has been on developing a specification which can be uniformly applied statewide in successfully using this strategy to maintain low volume roads.

The project collected information from PennDOT maintenance staff with experience in this sustainable variation on pavement maintenance and preservation strategy. A literature review identified comparable experience in Los Angeles County, California. Information was compiled from both these sources as background for progressing to an effective specification.

As PennDOT processed RAP material for chip seal aggregate for use in the summer of 2018, material samples were collected and evaluated. Gradations and asphalt extractions were performed to provide realistic data upon which a specification could be based.

The placement of RAP aggregate chip seals were monitored on several roads in July 2018. The chip seal product and placement process were evaluated as the product was placed.

The results of the investigation and materials analyses provided the basis for the development of a specification for using RAP as aggregate for low volume road chip seals. A draft specification has been prepared and is being implemented to specifically allow and control the use of RAP as chip seal aggregate in Pennsylvania. The specification is based on a revised RAP gradation developed from the work described herein.