ANDERSON — For many highway officials in Indiana, the chore of maintaining more than 200,000 miles of paved roads around the state is a seemingly perpetual process of planning, proposing and paving.
A new soy-based concrete sealant may also make it an environmentally beneficial task.
PoreShield, a substance its inventors describe as a concrete durability enhancer, is gaining traction as a promising solution not only for lengthening the lifespan of roads and bridges, but also as a boost to improving the environment.
“Since it’s applied topically and it absorbs into the concrete and fills the pores, it works on really any kind of concrete, whether it’s new or existing or whether it’s horizontal or vertical,” said Paul Imbrock, who served as the technical lead for the Indiana Soybean Alliance’s PoreShield project. “We’ve done a lot of bridge decks, and it’s been really well received, especially around the state of Indiana.”
The solution is applied to surfaces by spraying from backpack-style tanks, much like mosquito repellant treatments. Since it’s almost completely natural, those applying the product need no personal protective equipment.
Earlier this year, workers in southern Indiana’s Orange County applied PoreShield to some of the county’s more than 50 bridges. The county used an ISA grant valued at about $2,000 to purchase a 55-gallon drum of the solution – money officials believe was well spent.
“We did some of the sealing over running water, and it was nice to not have to stress out if we got a few drips down in the stream,” said Carl Anderson, highway superintendent in Orange County. “I do like the product. Any time you can keep the moisture out of those cracks, it’s going to make it last a lot longer.”
PoreShield emerged from a years-long research project at Purdue University undertaken in part to meet a request from the Indiana Department of Transportation for a more durable, cost-effective alternative to hazardous, silane-based sealants in use in the early 2000s.
“An environmentally friendly, sustainable product was certainly one of the aims that came out of that research project,” said Scott Manning, deputy chief of staff for INDOT. “That was one of the intents, along with being able to achieve the desired results from a standards and specifications standpoint in the field as well as cost effectiveness.”
The problem addressed in the research, Imbrock explained, originates in the design of most roads in use today.
The center lines cover pavement joints that must be cut in order to control cracking near those joints. But cutting those joints, he said, leaves tiny hollow areas that invariably attract water which, over the course of a year’s worth of Indiana weather, repeatedly freezes and melts. When repeated over several years, Imbrock said the process “leaves crystal and salt behind…and really aggressively deteriorates that pavement.”
A team led by Purdue engineering professors Jason Weiss and Bernard Tao began researching soy methyl ester, a substance produced when triglycerides are chemically converted into biodiesel fuels. They found that, with its non-toxic properties and scarcity of volatile organic compounds (VOCs), soy methyl ester is slow to evaporate, which prolongs its useful solvent life and increases its effectiveness as a preserving agent for mixtures like concrete.
Imbrock noted that road treatment methods which made use of agricultural products already existed, but weren’t as environmentally friendly as the approach the emerging PoreShield technology was built on.
“I think one thing that these professors had in mind was that for something to work on this level, it needs to be very scalable as far as the technology being able to grow,” Imbrock said. “The goal was for departments of transportation to be able to take something like this on and use it on every mile of concrete pavement.”
Each gallon of PoreShield solution is made from a bushel of soybeans, according to the ISA. A gallon covers, on average, about 180 square feet of bridge decking, and approximately 200 bushels of soybeans will produce enough solution to treat a mile of two-lane pavement.
“We’re thrilled with it as much as anything because it’s another way folks can use soybeans,” said Dave Blower, news and media relations manager for the Indiana Soybean Alliance.
Manning noted that while PoreShield can be used in virtually all types of road projects, its longer cure time — a result in part of the soy methyl ester needing longer to evaporate — makes it more ideally suited for major building or reconstruction projects, as opposed to quick overnight patch jobs.
For now, INDOT likely will not make PoreShield a mandatory component in its project contracts, he said.
“It’s one tool in the tool kit,” Manning said. “It’s really identifying on a case-by-case basis and determining which products can best meet our needs in a given scenario.”
© 2024 Community Newspaper Holdings, Inc.