WINDHAM – A new chemical is coating Windham’s roads this winter, as the town looks to cut down on the damage done by road salt.

The Windham Public Works Department has replaced the salt additive calcium chloride with magnesium chloride, and thus entered a debate over the best way to keep roads clear of ice and snow while cutting down on the corrision that the chemicals can cause.

Windham Public Works Director Doug Fortier said the department this summer received a shipment of magnesium chloride to replace its 2,000-plus gallon storage tank of liquid calcium chloride, which it depleted last winter.

“Mag,” as Fortier refers to the liquid de-icer, works similarly to calcium chloride by chemically boosting rock salt’s ability to melt snow and ice at lower temperatures.

There are two main reasons why the town switched over. The magnesium chloride costs 3 cents less per gallon, and with the town averaging 12,000 gallons per year, the cost savings is substantial, Fortier said.

Also, magnesium chloride is said to be much less corrosive, up to 50-60 percent less according to some studies, and Fortier hopes it will cause less corrosion to the metal undercarriages of plow trucks as well as other vehicles on the road.

Windham is the only municipality in the area to make the switch to magnesium chloride. Public works directors from Westbrook, Gray, Bridgton, Raymond and Standish say they still use calcium, as sparingly as they can and only when temperatures fall below 15 or 20 degrees, the point at which salt’s ability to melt ice diminishes.

Gorham doesn’t use either chemical, and has instead switched to a salty brine that when mixed with rock salt helps to melt ice at lower temperatures. In Raymond, Public Works Director Nathan White said the department uses calcium chloride sparingly, and only has one truck that can spread it. Most towns that use the calcium chloride opt for a corrosion inhibitor as well.

Ongoing debate

According to Fortier, there is a growing debate in the municipal plowing world regarding how to effectively treat roads while causing the least corrosion to vehicles. All salt corrodes to one degree or another, he said, but finding the balance between effective melting and preservation of metal is a constant challenge.

The issue is especially important in Windham, since the town’s public works garage on Windham Center Road doesn’t feature a wash bay where plow drivers can clean the undercarriages of their vehicles.

“We’re in it, constantly, and one of the things we battle – and I have said this at council meetings – is not having a place to wash effectively,” Fortier said. “If you come down here at midnight you can hear the rust eating our trucks. I’m exaggerating, but part of the inadequacy of this building here is we don’t have a wash station.”

Other departments, including Gorham and Gray, on the other hand, thoroughly wash their vehicles after every storm.

“Everything gets a heavy bath after each storm,” Gray Public Works Director Steve LeVallee said. “When you’re sitting on $25 million worth of equipment, it’s pretty smart to keep them well cleaned.”

Calcium chloride came into vogue in the 1990s, when drivers started demanding clean roads soon after storms cleared. Public works officials say driver demand has increased to the point where motorists expect ongoing efforts from plowing services to keep roads cleared during storms – and call to complain when their expectations aren’t met.

So, to comply, most towns now pre-treat roads with a salt and calcium mix to limit ice and snow build-up. Without the calcium or magnesium additive, which sprays onto the salt-sand mixture, rock salt alone would do little to limit the build-up, Fortier said.

While motorists likely appreciate a quicker commute, the use of calcium chloride has damaged their vehicles, said Pete Bailey, owner of Route 302-based Pete’s Auto in Windham.

“We’ve seen a lot of brake lines, oil pans, power steering pumps, exhaust manifolds,” Bailey said, while scanning his own tow truck for rust. “It’s attacking stainless steel, aluminum, steel, cast iron, and I’m hoping that swapping it over to this other salt, magnesium chloride, is going to make a difference.”

“See here?” he said, chipping off rust from the truck’s fuel tanks and rear bumper. “You can see the damage.”

At Windham Public Works, fleet maintenance supervisor Dave Poree said he constantly battles salt’s effect. He is in the process of changing over brake lines in town vehicles to a new copper nickel alloy that doesn’t succumb to calcium chloride’s corrosive effects. He has also coated the 60-plus electrical connections in each plow truck with a dielectric gel that fights corrosion and moisture.

Years of experience

While Windham is one of the few area towns to use magnesium, the state Department of Transportation, which plows some of Windham’s main thoroughfares, such as parts of Route 202 and 115, has been using “mag” since 2005.

Brian Burne, a highway maintenance engineer, said the jury is still out on whether magnesium is less corrosive than calcium.

“You can find all kinds of research online. There are calcium supporters out there and magnesium supporters out there,” Burne said. “But you can’t replicate in a lab the conditions you find out in the field.”

Dave Poree, Windham Public Works fleet maintenance supervisor,
coats an electrical connection on one of Windham’s plow trucks to
fight corrosion and moisture. In an effort to reduce the effect of
corrosion from road de-icer, the town has recently switched to
magnesium chloride, which is said to corrode metal at half the rate
of calcium chloride. (Staff photo by John Balentine)