Environment

New biopolymer gives asphalt roads a soybean-based-boost

A paving project demonstrated SoyLei Innovations' soy-based asphalt technology at last year's Farm Progress Show near Boone, Iowa
Joclyn Bushman/Iowa Soybean Association
A paving project demonstrated SoyLei Innovations' soy-based asphalt technology at last year's Farm Progress Show near Boone, Iowa
Joclyn Bushman/Iowa Soybean Association

Along with their use in foods, soybeans have also been utilized as a source of graphene, a greener alternative to mulch, and an ingredient in longer-lasting tires. Now, they're additionally being used to extend the life of asphalt roads.

Usually, in order to make asphalt more pliable and thus less likely to crack, a synthetic rubber known as polybutadiene is added to it. Not only is that rubber in short supply, but it's also carcinogenic – and as is the case with other petroleum-based materials, the process by which its raw ingredients are obtained isn't very eco-friendly.

With these drawbacks in mind, scientists at Iowa State University looked to soybeans as an alternative. Led by Prof. Eric Cochran and Dr. Christopher Williams, they eventually developed a process for converting soybean oil into a biopolymer that closely matches the performance of polybutadiene.

The production process was initially a bit impractical, as it required the oil to pass through three reactors over a 24-hour period. Now, in a process called Poly100, batches of the biopolymer can be produced in just a few hours via a single reactor. According to the university, no volatile organic compounds are produced, and none of the oil is wasted.

The technology has been commercialized by spinoff company SoyLei Innovations, which is marketing the biopolymer under the trade name of BioMAG. It's being offered in several variants, including one for use in virgin asphalt, one that allows a greater amount of recycled asphalt to be used in roads, and one that helps rejuvenate asphalt shingles.

It should be noted that while the farming of soybeans may seem eco-friendly as compared to the mining of oil required for petroleum-based materials, there are still some concerns regarding its effects on the environment. For instance, the majority of soybeans are grown in Brazil, where large areas of rainforest are cut down in order to make way for farms. Additionally, shipping the beans from Brazil to other markets contributes to greenhouse gas emissions.

Sources: Iowa State University, SoyLei Innovations

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5 comments
TechGazer
So, you get people driving on these roads ... starving because the food supply is going into roads? I suppose if they're too starved to drive, the roads will last longer. If they spend all their money on food, can they afford to drive? Okay, I suppose this technique will make roads last longer. Releasing bioweapons will make roads last longer too, if road longevity is all you care about.
paul314
Replacing as much of asphalt paving as possible with non-carcinogenic ingredients sounds like a good idea, especially because so many of the compounds in current mixes end up leaching into soil and waterways.
ljaques
Biopolymer is making its rounds in both concrete and now asphalt roads, it seems. Good stuff.
Now, can the manufacturers promise that the soy stuff will give the roads boobs =only in the potholes=, where it will do some good?
TpPa
That is great that it would work just as well, and not kill us. BUT we are in a world wide food crisis, we waste corn on ethanol that isn't any better after all that is put into growing and make in it, now we want to use soybeans for millions of miles of roads, sorry stop both, the world needs the food.
madsci
The oil from soybeans and the protein (most important food component) are two different things.