Originally created 07/31/05

Enzyme can make dirt roads durable, man says



ATLANTA - Thomas Settles grew up on a dirt road in Edgefield, S.C., a road so crummy it washed out completely after a heavy rain and he sometimes couldn't get to school. Summers were spent choking at the road's dust.

Mr. Settles, 53, owns a paving company in Atlanta and is on a mission to save poor Southerners from the indignities he grew up with. He's out to make dirt roads as good as paved ones.

"Look at this," he says, holding up a plastic jug of molasses-looking brown stuff. "This is all it takes."

The brown stuff is an enzyme called PZ-22X that can toughen dirt roads and help them stand up better to rain. He says it will be a blessing for rural communities that can't afford to pave all their roads.

Mr. Settles didn't invent the enzyme, but he bought the rights to it, christened it Pave-Zyme and is getting permission across the Southeast to test it on dirt roads.

Mixed with water and sprayed on dirt, the Pave-Zyme acts as a sealing agent, making the dirt more impermeable to water.

"It seals, it acts as a dust suppressor and it compresses," says Mr. Settles, whose claims about the enzyme would seem ridiculous if he didn't appear to believe them.

He says Pave-Zyme can improve health (by reducing dust in the air around dirt roads), narrow the education achievement gap between rich and poor (because kids living off dirt roads wouldn't have trouble getting to school) and otherwise revolutionize life in rural America.

And he's spreading the dream.

Atlanta - which still has some dirt and gravel roads - will test Pave-Zyme on three roads starting in August. The enzyme recently was put down on a dirt road in Aberdeen, Miss., and also is being tested in Macon County, Ala.

Mr. Settles says Pave-Zyme can harden a dirt road for $60,000 to $100,000 a mile - versus $180,000 and up to put down a mile of asphalt.

He isn't charging for the tests, where Pave-Zyme is mixed with water and sprayed on dirt or used under asphalt to make regular roads hold up longer. Mr. Settles thinks that once local officials see how well it works, they'll come back to buy.

"It was a win-win," said Atlanta City Councilman Ceasar Mitchell, who sponsored the idea of allowing Mr. Settles' company to try Pave-Zyme for free in Atlanta. Included in the city's test is a dirt road where a girl died three years ago when her bike hit a pothole. The city still hasn't found money to pave that road.

"It's just unsightly," said Mr. Mitchell, adding that dirt roads often attract illegal garbage dumping.

In other communities, dirt roads can be dangerous. In Brantley County in southeast Georgia, which has 700 miles of dirt roads, emergency workers have reported getting stuck on their way to calls.

"It's always a challenge. In the winter when it's wet, you can get stuck. In the summer, it's all dust and sand, and you can get stuck in that. It happens quite frequently," said Tim Crews, the director of the county's Emergency Medical Service.

Mr. Settles says Pave-Zyme makes a road good for five to seven years, shorter than asphalt paving but still an improvement from plain dirt, although road officials were skeptical.

Experts warn Pave-Zyme probably isn't a low-cost cure-all. Other hardeners have been tried before, and products such as calcium chloride already are regularly added to dirt roads to help them last and reduce dust.

Nothing, so far, has completely solved the problem, said Dennis Rice, who puts together a quarterly newsletter on road technology for the Georgia Department of Transportation.

"If you want a road to be like it's paved, you've got to pave it," Mr. Rice said.

Dirt-road improvements are especially troublesome in the South, where heavy rains and hot summers work against road hardeners, he said.

"You really have to have something you can hold together real tight," such as gravel used in pavement, he said.

Mr. Rice and other transportation officials aren't completely dismissing Pave-Zyme. The Georgia DOT is monitoring the Atlanta test and might consider endorsing it for local use if Pave-Zyme performs well. (The department doesn't directly maintain any dirt roads; all the ones in Georgia are maintained by counties and cities.)

Georgene Geary, a materials and research engineer for the Georgia DOT, said she's curious to see whether Pave-Zyme does the job.

"We've had other products come through here and they weren't successful. They just didn't hold up," she said.

Mr. Settles is convinced he's about to change some minds.

"In some communities, they just can't afford to pave all their roads," he said. "This is something that will consistently make the roads better at a price they can afford."

It's wait-and-see for officials.

"There's a lot of snake oil out there that doesn't work, but the only way to know for sure is to put it down and try it out," Mr. Rice said.