Environmental Impacts of RAP Research Study Completed

Rowan University, in collaboration with Columbia University and the Stony Brook, has completed a 2-year study of the environmental impacts of RAP. This study was conducted on samples of RAP from stockpiles throughout New Jersey. The conclusions of the study are that RAP has no detrimental impact on the environment.

Specifically, the research included samples of RAP from stockpiles in northern, central, and southern New Jersey and subjected those samples to a series of tests to determine whether polycyclic aromatic hydrocarbons (PAHs) or heavy metals could leach out or the RAP or become airborne. In addition, the leachate from the experiments was used to determine whether it would impact marine environments, testing for mortality and genetic damage to fish embryos.

The recommendations from the research study include:
  • RAP may be used as an unbound material in all environments except those which are highly acidic (pH £ 4.0)
  • Acceptable, beneficial uses of RAP include, but are not limited to, using the unbound RAP as surface materials for parking lots, farm roads, or pathways; for quarry reclamation; as non-vegetative cover underneath guiderails; and mixed with other materials for subbase or base materials; in addition to the current uses in hot mix asphalt applications
  • Highly acidic environments are defined as those where sulfur-containing minerals may come into contact with RAP (mines) or where other materials may decompose and create an acidic environment (landfills) where the pH £ 4.0
  • If RAP is proposed to be used in highly acidic environments (pH £ 4.0), testing is recommended to determine whether PAHs or heavy metals may leach from the RAP

The New Jersey Asphalt Pavement Association has always maintained that reclaimed asphalt pavement is safe for reuse in a variety of applications. This research study validates our position.

RAP is:
  • Safe
  • Sustainable
  • Non-toxic
  • Economical

The NJAPA will work with the New Jersey Department of Environmental Protection and the New Jersey Legislature to implement changes to the reuse of RAP in recognition of the findings of this study.

The Technical Brief and the full report are available here:

EIRAP Technical Brief

EIRAP Final Report