Road brining before winter storms is gaining more traction around Philly and the nation

With ever-growing concerns about the damage that salt is doing to the environment, not to mention to vehicles and footwear, highway departments have been turning to a rather prosaic solution to cut back on its usage: home-brewed saltwater.

You might have noticed that more roadways in the region are bearing those rows of ghostly white streaks, like so many omens of winter icy horrors to come, whenever storms are in the forecast.

That’s the visible evidence of the “anti-icing” brine movement, which has been gaining popularity around here and the nation. Studies affirm that it has been a major salt saver, if not a popular one.

“The really, really big advantage of brine is that you waste less. ... It’s going to be so much better for the environment,” said Victoria Kelly, a program manager at the Cary Institute of Ecosystem Studies in upstate New York.

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“We can definitely spread less salt,” said John Krafczyk, maintenance manager for PennDot’s Philadelphia region, adding that it can reduce usage by as much as 45%. Some research shows it can cut use by as much as 75%, said Stephen Schapiro, spokesman for the New Jersey Department of Transportation.

The concept has been around for decades, but highway departments didn’t get into pre-storm brining until about 2010, said Stephen J. Druschel, a professor of civil engineering at Minnesota State University and an expert on brining, which he acknowledges is a lonely pursuit in the academic community. (The “real experts” are the truck drivers, he says.) The origins of the practice are somewhat unclear, he said, and statistics on its usage are wanting.

But its popularity is indisputably spreading.

Some brines contain additives — New Jersey has used beet juice when it’s been extremely cold — aimed at further combating low temperatures, but basic brine is a mixture of 23.3% salts. Highway departments make it in massive mixers and then spread it with trucks equipped with udder-like dispensers. As for why the 23.3%, that’s the maximum salt concentration that water can dissolve.

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The liquid adheres to the paving, as opposed to salt pellets that bounce off of hard surfaces and scatter like so many hailstones.

“Treating roads before a storm is a lot like cooking pasta,” said Druschel. The liquified solution can speed up the melting of ice and snow on streets the way adding salt can speed the heating of a pot of water for pasta, said Druschel. One doesn’t have to add salt to boil the water, he said, but “it just takes longer.”

The mixture gloms on to the paving and works its way into nooks, crannies, and cracks in ways pellets cannot. That prevents or at least delays snow and ice from forming an epoxy-like bond to a road surface.

“The last thing I want that to do is have it pack and stick to the road where we can’t peel it off,” said PennDot’s Krafczyk.

Experimentation with brines dates to the 1960s, said Daniel Sullivan, a spokesman for the salt giant Cargill.

Druschel said that more than 25 years ago, the Minnesota Department of Transportation came up with the concept of “pre-wetting” salt before putting it on the road. That now is a common practice among highway departments, including PennDot, and was a precursor to today’s pre-storm brining. “That was a big step forward,” Druschel said.

In some instances water might constitute two-thirds of the weight carried on snow-fighting trucks, said Druschel.

A major obstacle was equipment, said the Cary Institute’s Kelly.

The old snow-fighting trucks were manufactured to spread crystals, not brine. “That was one of the stumbling blocks. What do we do with all these old trucks,” she said. “Spraying is different from spreading.”

In addition to the trucks, brining requires other machinery to mix the melter cocktail.

But another factor was “inertia,” she said. It can just take awhile for highway departments to change their ways.

PennDot’s Krafczyk said it has looked at additives, but, “We didn’t see any advantages.”

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Kelly said that “the jury is still out. There just isn’t anything in the scientific literature just yet. Ideas get formulated and implemented and science tries to catch up with, how effective is this?”

They make a “tiny bit” of difference, said Druschel, adding that Minnesota has used corn water and sugary beet residue. He said the deer are grateful for the resulting roadside detritus — to them it’s, “Oh, sticky toffee,” he said. Unfortunately, he added, that has led to more deer-car collisions.

The short answer is yes, and brining’s impacts on metal have been the subject of multiple media reports.

Kelly, however, argues that salt is salt, diluted or otherwise, and that it’s going to corrode, period. She said the fact that brine is more evenly spread might enhance the impact, but that no one she’s aware of has conducted a controlled experiment to isolate the effects of brine versus dry pellets.

“I think the bottom line is we’re going to see just as much corrosion,” she said.

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Cargill’s Sullivan concurred. Regarding corrosive effects, he said, “It is unclear, as there is little hard data to confirm this.” He added that even solid salt treating snow and ice “is eventually converted to a brine anyway.”

Kelly, who lives in a small town about 90 miles due north of New York City, says that when snow is in the forecast, she’ll be walking on a half-inch layer of rock salt in front of the local library and post office. She wondered whether perhaps someone could brine the sidewalks with, say, a backpack sprayer.

PennDot’s Krafczyk said he did try to brine his own driveway. He used a hydrometer to measure the salt level in the water in his sprayer and then fired away. Unfortunately, the nozzle quickly clogged up after he had covered all of one square foot. Eventually, he did get it to function.

“It was a lot of work,” he said. “Was it worth it? No. I found it better to take a handful of salt and throw it on the driveway.”