By: Dan Lemke
Concrete is everywhere. From roads and sidewalks to home foundations and walls, concrete is ubiquitous to transportation and construction. Unfortunately, it also has its limitations.
“There are two kinds of concrete,” said AURI Business and Industry Development Director Harold Stanislawski, “concrete that’s cracked and concrete that’s likely to crack.”
AURI, along with the Minnesota Soybean Research & Promotion Council (MSR&PC) and the Soy Transportation Coalition, have set out to explore the utilization of soybean-oil based concrete enhancing products to preserve concrete’s qualities. Funded by the Soy Transportation Coalition, this work intends to increase utilization of Minnesota-grown soybean for applications in the transportation and construction sectors.
Applications of products, like soy-based concrete durability enhancer PoreShield®, show the ability to extend the life of concrete and help protect the often massive investments made in concrete.
Developed by Purdue University as a solution to extend the life of joints in cement roadways, PoreShield is a soy-based liquid that aims to enhance the durability of concrete.
“One interesting thing about this technology is that it came out of a need,” said PoreShield Technical Lead Paul Imbrock. “It wasn’t trying to find a replacement for something that exists, it was actually the Indiana Department of Transportation that came to Purdue University civil engineering and to some of the professors there and said, ‘hey, we have this problem.’”
The primary problem was deterioration seen in saw cut joints made in concrete roadways. These saw cuts are made to limit cement cracking and highway cerws typically fill the cuts with hot asphalt or insert a rod into the cut and cover iwt ith silicone caulk to keep water, ice and salt from getting into the crack. Even with these preventative measures, freezing, thawing and salt infiltration eventually break down the joints.
Imbrock says several Purdue professors collaborated to develop a soy-methylester- based solution. The result was PoreShield, which is sprayed into the saw cut joint as a liquid. Then, because concrete is porous and takes in moisture like a sponge, the PoreShield is absorbed into the concrete to protect the joint. Unlike a concrete sealer that simply forms a protective layer, PoreShield is absorbed deep into the pores of the concrete to increase its durability. “Water and salt that seeps into the joint can’t absorb into the concrete, so it simply runs through and drains out,” Imbrock explains. “It’s a little bit of a different school of thought, and a more innovative way of trying to provide that next level of protection.”
Joint deterioration is a critical factor in the surface life of concrete pavement. Imbrock says that nine times out of ten, saw cut joints are where concrete deterioration is going to start. Joints begin to open, exposing the concrete to water and salt, as well as to the pounding of vehicles. Imbrock says PoreShield works to keep that from happening, extending the road’s useful life, and delaying the need for repairs.
“Soy-methyl-ester can penetrate deep into concrete. If we spray it onto concrete and topically apply it, it’s going to spread into every nook and cranny that water can get into in the future,” Imbrock explains. “We’re trying to get into the pores of the concrete ahead of water and salt. We fill it with a viscous, hydrophobic fluid like soy-methyl-ester, so that we’ve essentially created a barrier inside the pore network of the concrete that creates that separation. Water and salt on the surface must find a drainage path or wash away rather than absorb into the pores where it’ll start to cause damage.”
Imbrock was a graduate research assistant at Purdue in 2008 when research began on the development of a concrete protectant. The Indiana Department of Transportation and Indiana Soybean Alliance supported the research and initial results were published in 2011. The first field tests were conducted on roadways
“We’ve had it on real world pavements in Indiana for 10 years and the pavement still looks like it did on the day PoreShield was applied,” Imbrock said. Because PoreShield is a soy-based product, the Indiana Soybean Alliance was interested in supporting its research and development.
“One of our challenges is creating new opportunities for soybeans to be used,” said Ben Forsythe, Sustainability and Value Creation Director for the Indiana Soybean Alliance. “That value creation vertical is looking into new and innovative ways to utilize the crops we’re growing today, and PoreShield is another great
opportunity for that, plus it enters a bit of a different market.”
Stanislawski said the PoreShield product was introduced to the Agricultural Utilization Research Institute (AURI) by the Soy Transportation Coalition and the MSR&PC. The MSR&PC supports new markets and new uses for soybeans and the Soy Transportation Coalition has an initiative to help state, county and local units of government find innovative ways to economically build or maintain important rural infrastructure like roads and bridges that keep ag products moving.
Stanislawski worked with PoreShield and the city of Hutchinson, Minn. to apply the product on an airport fueling pad, on a walking path and a bridge deck.
“I really like this product,” Stanislawski said. “There’s minimal training required, and no specialized equipment needed to apply it. You simply follow label instructions and apply it with a hand pump. It’s another biobased product that comes courtesy of the soybean plant.”
Hutchinson Public Works Manager John Olson said the city previously used a soy-based asphalt protectant with good success, so he didn’t hesitate to try PoreShield.
“When the opportunity came up, I thought it made a lot of sense,” Olson said. “We’ve seen the value of biobased preservation, so we wanted to give it a try to see how it behaves. This is one more opportunity to try something different to keep what we already have in good shape for as long as possible.”
AURI is working with PoreShield to help raise awareness of the product and to demonstrate how it can be used to protect municipal investments while generating a new, value-added use for soybeans.
Because soy is the primary ingredient in PoreShield, increasing its use increases demand for soybeans. Stanislawski said that a PoreShield application on a bridge deck 20 feet wide by 40 feet long would utilize the equivalent of 640 bushels of soybeans or 960 gallons of soy oil.
“That is good soy utilization that’s meaningful,” Stanislawski said, “and there are a lot of concrete bridge decks around Minnesota, the country and the world.”
“We’re able to provide another biobased answer to the problem of road preservation,” said Mike Youngerberg, Senior Director of Product Development and Commercialization for Minnesota Soybean. “This product has a lot of versatility from roads and streets to numerous other applications.”
Imbrock said one bushel of soybeans makes oneand one-half gallons of PoreShield. Treating only the pavement joints on 10 miles of state highway used 3,600 bushels of soybeans. New innovations with soybean oil are occurring regularly in this space. While this trial focused on Poreshield, other concrete preservation products are commercially available to meet the goal of preserving and extending concrete life as well.
Imbrock said one application of PoreShield protects for 10 years. It could last longer, but real-world trial data only dates to 2012. Beyond increasing the life of concrete, Imbrock said PoreShield also protects infrastructure investments.
“Something that we were told at the beginning of our research was that if you have pavement joint deterioration and you have to go gouge it out and replace it, you’re talking about $1 million per mile,” Imbrock said. “Obviously those are taxpayer funds that could be put to better use, either making some new roads or making things more accessible rather than replacing concrete that is in service but deteriorating.”
While PoreShield can add durability to any concrete surface, Imbrock stated the company is focusing on the transportation and construction markets first.
A lot of infrastructure, especially in rural areas, needs repair or replacement. Imbrock said he’s had a county engineer tell him that five bridges in his county needed replacement. However, replacing just one bridge would eat up five years of the engineer’s budget. Protecting infrastructure investments with a low-cost product like PoreShield that can dramatically extend the life of roads and bridges is becoming an increasingly attractive option. Poreshield can be applied
anytime after 7 days of a concrete pour and application requires no personal protective equipment.
Becker County Initiates RePlay Demonstration Site
In late July 2022, a soybean-based road sealant, RePlay™, was applied near Callaway, Minn. in Becker County on Highway 14. AURI Business and Industry Development Director Harold Stanislawski and United Soybean Board Director Bill Zurn met with Becker County Commissioners and highway department representatives to answer questions. Bargen Inc. of Mountain Lake, Minn. applied the material. Signage was placed marking the treated roadway.
RePlay has been used as an asphalt preservation product for over a decade in the city of Hutchinson, MN, and has been applied on roughly 130 locations across Minnesota.
RePlay Agricultural Oil and Preservation Agent® (RePlay), is a patented product created and manufactured by BioSpan Technologies, Inc. A life-cycle cost analysis conducted by SRF Consulting Group in 2021 revealed that road segments treated with RePlay have a statistically significant lower rate of pavement degradation compared to untreated segments. SRF combined rates of degradation from the statistical analysis with a model for untreated asphalt pavement degradation to estimate RePlay service life (worst to best-case scenarios). The service life analysis demonstrated that RePlay could increase the longevity of road surfaces by 2-7 years. RePlay uses approximately 90 bushels of soybeans per lane mile. Learn more about RePlay and related projects on AURI’s website.