Turn dirt into hard roads with enzyme-based additives

Around the world, there are thousands of kilometres of rural roads that support farms, ranches, mines, forestry and other operations; these roads are vital to many people and businesses, but often are left unpaved for cost reasons.

These roads, usually surfaced with gravel, tend to break down and require more regular maintenance than paved surfaces to keep them firm. There are a number of different tactics for solidifying road surfaces, but one company has taken a scientific approach to creating durable road surfaces at lower cost.

Substrata's approach to road surfacing focuses on the use of enzymes, a product its founder John Battistoni developed in the 1970s. Originally founded as International Enzymes, the company started out in soil stabilization, degreasing and deodorizing all done without problematic environmental effects. 

Today, the company has focused its efforts toward soil management in rural areas around the world, and now is targeting road construction and maintenance, according to CEO Royal Marty.

"Before I purchased the company we did the majority of our business internationally in developing countries; they rely a lot on unpaved roads," Marty described. "But you know, I think a lot of people forget about the amount of unpaved roads we have here in North America - there are thousands upon thousands of miles of unpaved roads in the U.S. and Canada. . . a lot of rural areas that rely on infrastructure but don't necessarily have the budget to build a regular asphalt road that will cost millions of dollars."

Stabilize native clay soils
Where asphalt paving is less feasible for financial reasons, unpaved roads provide key travel routes. In most cases they will be compacted and covered with gravel, but that requires regular maintenance work to keep the surface smooth and ensure safe travel. Substrata's Perma-Zyme soil stabilizing product combines with native clay soils to firm up the surface much more effectively than simple gravel covering.

When the product is applied, enzymes interact with the clay particles in the soil and create an electrochemical reaction that permanently bonds the material together, Marty explained.
"You come through with a grader, a blade or a till and rip up the soil, bringing fresh soil from underneath. Then you come through with a water truck that has Perma-Zyme in it - it's heavily diluted; for a kilometre of two-lane road you would need two five-gallon pails," he explained. 

"You spray that onto the soil, then come through with a grader and mix it into the soil as much as possible. Then you compact it - that's the most important part of the process, because that's what starts the electrochemical reaction."

On an unpaved road, the structure formed by Perma-Zyme is much firmer than might be gained by other methods, Marty said, and much more stable.

"Most unpaved roads have gravel or another material on the top, and you have to constantly be reapplying that gravel. When you use Perma-Zyme, you'll probably put a layer of gravel on the top of the road, just to increase the friction, but that gravel's not going to go anywhere - it's just going to stay right on top," Marty explained.

The surface is expected to last around 10 years with little to no maintenance, Marty said. In some places, it is also being used as a base layer for paved roads.

"We have a lot of rural areas where they'll apply Perma-Zyme, mix it into the soil and compact it, then instead of putting down a layer of asphalt 8 to 12 inches thick, they'll just put a few layers of double chip seal down on top of it," he said. 

"Perma-Zyme is giving you the strength you need for that road, and then the chip seal gives you a nice load-bearing surface."

Cold weather not a problem
Perma-Zyme also helps cut down on dust problems - a frequent challenge on rural roads - and is able to handle cold weather as well.

"It can go through freeze-thaw conditions just fine. . . if we go back to the electrochemical bonding, those particles are permanently bonded together, and when that happens no water can seep down into the soil. When it freezes and thaws, nothing can get between those particles and cause them to expand or contract," Marty described.

While much of its business has been done overseas thus far, Substrata has been working with a number of North American rural communities and finding success with its products, both for unpaved and surfaced roads. 

"We have been focusing a lot on working with rural areas in North America to provide them with a solution that will help them, either for their unpaved or paved roads, at a cost-effective rate," Marty said.