Quick look
Soy pavement technology developed by Iowa State engineers helped fix 24 miles of rural roads in northeast Iowa's Clayton and Fayette counties and the town of Volga. The "soy roads" used 12,000 to 15,000 bushels of soybeans and eliminated the need for 40,000 barrels of crude oil.
AMES, Iowa - A train of heavy equipment slowly worked its way across 8.6 miles of a northeast Iowa county road last summer.
The corn growing along C14 just south of West Union was dark green and high. Farmhouses and outbuildings were on the horizon. The ditches along the roadway were freshly mowed. It was a good day to fix a rural road built in the 1960s, patched up and covered over ever since, now deteriorated and even crumbling beneath the surface.
The fix was soy pavement technology developed by Iowa State University engineers.
The repairs to C14 were part of a full-scale, 24-mile demonstration of "soy roads" in rural areas of Fayette and Clayton counties and the town of Volga. Four different road projects used soybean-based paving products developed by Iowa State engineers Eric Cochran, the Mary Jane Skogen Hagenson and Randy L. Hagenson Professor in Chemical and Biological Engineering, Christopher Williams, the Gerald and Audrey Olson Professor in Civil Engineering, and their research groups. The technology is now produced by their startup company, SoyLei Innovative Products.
A full-scale project, indeed:
Leading the paving train along C14 was a tanker truck carrying refills of asphalt pavement emulsion, including soy-based binders, for rehabilitating and bonding recycled pavement material. Next was a semi pulling a tank full of water to cool the sharp bits of the next machine.
That big yellow machine ripped up the top 4 inches of a lane of asphalt, ground it and put it on a conveyor to the next machine. That one chewed up more of the pavement and mixed it with emulsifier, including soy oil polymers that replaced petroleum-based ones. In prior tests and demonstrations, the soy alternative has been the better option for binding and boosting pavement flexibility and performance.
The mixing machine dumped the cold and raw asphalt on the stripped roadway, and a trailing paving machine picked it up and spread a new and dark base layer across the lane for a pair of rollers to smooth. Paving crews later covered the base layer with a layer of hot-mix asphalt, also containing a soy-based binder.
