Commodities

Road builders have been modifying their techniques to adhere to Federal Highway Administration (FHWA) Superpave specifications—asphalt mix design specifications created as a standard for the industry.

Does RAP (recycled asphalt pavement) fit into the Superpave picture? At least one presenter at an event held by the Asphalt Recycling and Reclaiming Association (ARRA) believes the presence of RAP in Superpave mixes will increase. “With binder prices going up, we will see more use of recycled asphalt pavement in the future,” remarked Randy West of APAC Inc., Smyrna, Ga., at the “Superpave: Building Roads for the 21st Century” conference held in Denver.

West noted that when doing a Superpave mix design using RAP, virgin materials and RAP are blended to meet the applicable aggregate properties, gradation and volumetric properties of the Superpave specifications.

West said RAP percentages of 20% to 35% or greater often could be used without failing PB binder fatigue and low temperature properties. In some cases, he noted, extra caution may be required to assure achievement of the desired high temperature properties.

The use of mixes with stiffer PG binders may limit RAP percentages, added West. The Superpave Mixtures Expert Task Group has issued “Guidelines for the Design of Superpave Mixtures Containing Reclaimed Asphalt Pavement.”

N.C. DRYWALL CONTRACTOR STARTS RECYCLING OPERATION

Steve Davis, the owner of a gypsum drywall contracting firm based in Marshville, N.C., has purchased land and buildings from a former turkey farm to create a gypsum drywall recycling facility.

Operating under the name Union Gypsum, Davis processes his own residual gypsum materials and also operates a scale to accept materials from other contractors.

Partially using a grant from the North Carolina Division of Pollution Prevention and Environmental Assistance, Davis purchased the land, buildings and equipment necessary to process scrap gypsum drywall.

He sells his ground gypsum to area farmers at a price below what they have been paying for virgin agricultural gypsum, which is used as a soil additive by the farmers.