Adhesive road asphalt from hog wastes focus of current research

Thursday, October 18, 2012

The pork industry, highlighted during October -- National Pork Month, has, through use of various byproducts, made numerous contributions symbolizing its role in value-added agriculture.

Among the newest of these thanks to the efforts of a North Carolina A&T State University researcher, Dr. Ellie Fini, Ph.D. PE, among others, may improve the nation's network of highways and roads.

An assistant professor of civil engineering at A&T, Fini is project leader of current research studies for use of swine wastes from on-farm lagoons for adhesive asphalt.

The asphalt project was outlined at the North American Manure Expo, Prairie du Sac, Wisc. in August.

She terms the pork production waste a "promising candidate" for partial replacement of the current petroleum-based binder used for infrastructure repair.

Contacted by the Sentinel at her office in Greensboro, N.C., Fini said conversion of the wastes into a useable "bio-binder" for the asphalt used to repair highways and roads offers several important benefits to the pork industry as well as highway repair and maintenance industries.

"We see it as environmentally good in that, for pork producers, it offers a unique approach that addresses the continued concern over manure pollution and greenhouse gases," Fini said. "Use of the swine manure in this way can also lessen storage loads for a pork operation and mean a reduction in lagoon cleaning time for increased operation maintenance efficiency."

This adhesive asphalt also provides the highway construction industry with an eco-friendly, renewable and lower-cost repair option as crude oil prices increase, she said.

A comparative production cost savings is estimated at 13 cents for the bio-adhesive as compared to 53 cents for an asphalt product.

Fini said that use of the adhesive also addresses the increased concern about depletion of petroleum resources.

In addition, the adhesive has improved cracking resistance, an important factor especially in the winter.

This, she said, is a result of what researchers call the black box (reactor) technology to extract minerals used in the adhesive production.

The black box technology utilizes a hydrothermal process to initially convert the swine wastes to a bio-oil, Fini said.

The bio-oil is then fractionated to extract water, solid residue and some of the organic compounds with the "sticky residue" remaining used as the asphalt binder replacement.

Fini said the A&T researchers are presently interested in working with pork producers in the three-state area with sufficient hog numbers to justify their participation in the research underway and possibly becoming a part of the project.

The research team is also interested in possible industrial groups or companies including those in Iowa and Nebraska wanting to learn about their possible involvement in the bio-binder research, Fini said.

Additional project information is she said available by contacting her at