Asphalt concrete, more commonly known as blacktop or asphalt, form the mainstay of roads throughout the world. Asphalt concretes form strong weather resistant yet low cost materials for paving roads.  These mixes can support heavy pedestrian and vehicular traffic with durability and wear resistance. Among its many advantages, asphalt concrete can also be recycled.  Asphalt concrete can be removed from existing road ways, ground in smaller particles, and the resulting ground mix (reclaimed asphalt pavement (RAP)) can be incorporated with fresh binder to form new roadway material.:th

Asphalt concrete is composed of a mixture of one or more bituminous binder materials ("binders") with one or more aggregate materials ("aggregates"). Aggregate generally forms about 93%-95% of the weight of the mixture. Binder is generally composed of asphalt, a highly viscous, tar-like substance of petrochemical origin which can also be supplemented with polymers to improve various properties (e.g., one or more of resistance to rutting, thermal cracking, fatigue damage, stripping, and temperature susceptibility).  However, the greatest difficulty in the use of RAP is determining the amount of binder present in the RAP as this has great importance in determining the formulation of the new asphalt concrete. Determination of the aggregate composition of RAP is simple in that the binder can usually be burned off from a sample of the RAP, leaving only the aggregate. However, determining the amount and utility of binder and binder- derived products in RAP is more complicated.  The variability in the fraction of binder that occurs in RAP that is able to melt and mix with virgin binder included in the concrete mixture makes it difficult to select an appropriate amount of virgin binder.

To aid in the formulation of recycled asphalt concrete, the inventors have developed a method of making asphalt concrete mixtures including reclaimed asphalt pavement (RAP). These methods allow an asphalt concrete mix designer to determine the amount of virgin binder that can be combined with RAP and virgin aggregate in order to satisfy the minimum effective binder content of a job mix formula for such a concrete mix. This permits a more efficient use of RAP and permits use of RAP in higher amounts in asphalt concrete mixtures.

Potential Application

A method to aid in the determination of the formulation of asphalt concrete recycled mixtures.

Opportunity

Capital spending in the United States on highways, roads, and bridges by all levels of government (federal/state/local) totals about $80 billion annually, about half of which comes from federal funding. Of this spending, 65 percent of the asphalt pavement market is publicly funded highway projects, with residential and non-residential construction making up the remaining 35 percent.

Rowan University is looking for a partner for further development and commercialization of this technology through a license.