Ester man experiments with coal fly ash
(Newsminer.com 07-29-2013) FAIRBANKS — Fairbanks has an abundance of coal fly ash, the byproduct of Interior Alaska’s many coal-fired power plants, and few places to put it.Much of the fly ash is destined to be thrown in landfills, but a small amount ends up in what was supposed to be Cole Sonafrank’s glass mosaic art studio. That’s because Sonafrank sees an opportunity, not just for himself, but for Alaska. It’s an opportunity to make a cement that is stronger, more durable, cheaper and more environmentally friendly than traditional Portland cement.
Sonafrank, a longtime Ester resident, computer programmer, artist and self-described renaissance man, has dedicated much of his time and effort to developing a cement that he says could radically change construction in Alaska.
“I took a long time deciding what to do with my life,” he said. “In college, I started as a physics major, switched to a philosophy major, got a degree in economics, and should have got a degree in art or computer science. And now I wish I got a degree in chemistry.”
Sonafrank began his quest for a higher grade cement when he began working with glass mosaics. He quickly found nothing on the market quite worked like he wanted to, so he decided to make it himself.
That brought him to geopolymer cements, a broad term for cements that employ materials and chemistry that are fundamentally different than the widely used Portland cement.
Portland cement is largely based on lime and silica, requiring large processing plants and a large release of greenhouse gases. The key to geopolymer cements is they can often be created with local raw materials, require little processing and can be made in a mixer.
Geopolymer cements are made with a different chemical bond than Portland cement that yields a much more stable bond.
Geopolymer cement and Portland cement can be mixed with rock aggregate into concrete, where it can be used for sidewalks, foundations, bridges and buildings.
Geopolymers have been studied since the 1950s, but there are thousands of variations and none were suited for Alaska’s unique raw materials or environment.
“This isn’t my invention. It’s not new technology,” he said. “You can make it from a whole bunch of different source material and how you do that depends on the source material. I’ve taken fly ash here and done 800 and some experimental mixes coming up with ones with different properties that work with materials we have here in Alaska.”
Sonafrank has been working for several years on perfecting the mix of fly ash-based geopolymer cement. He did much of his research at the Cold Climate Housing Research Center but has since taken his work home.
Outside his Ester home there are hundreds of neatly stacked concrete cylinders, each about the size of a Morton Salt container and marked with a different batch number.
Each sample is the result of a slightly different recipe that includes various types of coal fly ash from different local power plants (he says the Healy 1 power plant produces the best), blast furnace slag and a strong alkali like sodium hydroxide or potassium hydroxide.
The results are impressive by Sonafrank’s account. The geopolymer cement-based concrete cylinders have nearly twice the strength of Portland cement. It also doesn’t begin to break down nearly as quickly as Portland cement, so it’s less likely to crack and lasts much longer.
The geopolymer cement samples are much more resistant to extreme temperatures, expand and contract far less and are waterproof.
“It’s essentially a synthetic rock,” he said in his studio, surrounded by dozens of recent experiments. “You start to think about what these differences mean. They don’t seem like much, but each one has very serious implications regarding how you can take advantage of that characteristic and what it means to how you can use the material.”
He’s produced concrete foams that could be used for insulation, ultra-thin fiber-reinforced sheets and a wide array other applications in various shapes and sizes.
In homes, it would mean foundations that would be less likely to crack and less likely to leak. It also could be used to mass-produce masonry heaters, where its heat-resistant properties would keep it from cracking.
It also presents big potential at mines, where tailings or silt could be used to create geopolymer cements. Because it’s impervious to water and resistant to breaking down, it presents a good way to trap toxic waste products.
But despite the promise of geopolymer cement, you still can't pick up a bag at a hardware store or have a foundation poured with it anywhere in the United States.
“Why hasn’t this taken off? And if it’s so much better than Portland cement then why haven’t we used it all along?” he said. “Well Portland cement is much easier, and it’s also an established multibillion-dollar industry.”
The precise mixtures of geopolymer cements varies wildly depending on what you have to make it with and some parts, like the blast furnace slag, still need to be brought up from the Lower 48.
But Sonafrank is confident that with economies of scale geopolymer cement could cost more than 30 percent less than Portland cement and far less when you factor in its longevity.
To find adoption in Alaska, Sonafrank said geopolymer cements will have to go past the lab and be proven in the real world. That’s his next goal.
“In my mind (geopolymer cements) have the potential to change the development of Alaska,” he said.
Sonafrank says he’s looking for projects to prove his geopolymer cement mix works, and the clock’s ticking. There’s a possibility that a multimillion-dollar Portland cement plant could be built in Alaska, which would leave millions of tons of fly ash, volcanic ash and mine tailings in the waste pile.
He said in the near term, he’ll look to niche products that take advantage of geopolymer cement’s specific properties. That will include products like siding, roofing shingles and countertops.
“There’s lots of different ways to do this and the way that seems to work elsewhere in the world is to make niche products and not going after the structural replacement right away,” he said.
A studio expansion at his house will use geopolymer cement for its radiant heat floor, and a friend of Sonafrank’s plans to use it for the foundation of a new home.
Once the owner of a proud, bushy beard, Sonafrank recently trimmed it down to just a bushy mustache so he could more easily wear a respirator mask to continue work on geopolymer cements.
Despite the big uphill battle, Sonafrank said he’s not going to give up.
“There are people out there doing good things for the rest of the world, but I’m focused on what’s the best for Alaska and good for the world,” he said. “I believe geopolymers are a piece of that.”
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