Centre for Technological Research of Crete

Transcription

VO: The Center for Applied Energy Research, at the University of Kentucky, and Minova partnered on a new concrete product marked by unprecedented speed and strength. The goal, create a new kind of concrete that could save lives in damaged structures and underground mines. Rodney Andrews: The project that led to the development of this product was originally funded through National Institute of Hometown Security based in Somerset, Kentucky. Their program is directed at solving infrastructure and related issues for Department of Homeland Security. Tom Robl: NIHS and the Department of Homeland Security, they wanted something to repair shock-damaged structures. This is a tough assignment. You’re adding weight to the structure which is already damaged and weakened. So what you’ve done is you’ve created what’s called a “parasitic load”. Whatever you’re putting on there had better react quickly and had better form strength quickly. Bob Jewell: You can think of a supportive structure where the rebar is expose and the joints between beams and columns. You don’t have time to go in and clean off a structure, wipe away debris, clean up dust, this doesn’t make sense. So, you need a material that sticks, adheres to pretty much anything you spray it to, and still gives you the strength, compressive, flexural strength and integrity that you’re wanting out of the concrete. And the product from this project did just that. Peter Mills: They are cementitious products, which means that you just mix them with water and they set hard. They harden so quickly that not only are they set in a few minutes, they are rock hard in a few minutes. We’re talking structural strength in as little as 15 minutes of hardening time, which is unheard of in the world of concrete. Bob Jewell: What are we trying to achieve? Fast setting strength, but also, we don’t want it to fail catastrophically. In the case of first responders, you’re entering a building…you want some integrity beyond its load capacity and the fibers give you that. What you’re doing is creating a dense network of fibers. So, instead of breaking concrete and having one main break, fibers allow that crack to break into a multitude of cracks, so you’re dispersing that energy throughout the concrete. For a high-strength concrete, you’re looking at maybe 4 to 700 psi in flexural strength testing while the final product … we were achieving 1200 psi, tripling the capacity of its flexural strength. Tom Robl: You can imagine where you would have a shock-damaged structure or a military type application, but also, for example, in the mining environment, which Minova is, of course, very intimately associated with the mining environment. Peter Mills: We manufacture steel and chemical consumables for mining, tunnel and civil engineering markets. We also make a huge array of different cementitious products, particularly in America, which are sold to mines and used for making the mines safer and more productive. Rodney Andrews: The relationship with Minova is a great example of how we partner with companies to develop new products. Tom Robl and his group have been working with them for many years. It was a natural on this project to bring them in as a partner as they know the application methods, they know a lot of the chemistries—what is needed to be done to create a final product that can be sold. Peter Mills: I’ve often used Tom and his colleagues as a source of expertise when it comes to fly ash. Tom thought of us and our knowledge of cement products to help to work with them to develop this product for the infrastructure project. And that’s how Tekcrete Fast came about. Tom Robl: We started out with one product, and Minova’s already got two out of it. Peter Mills: The difference between Tekcrete Fast and Tekcrete Fast M is that the M has been specially treated so that it’ almost dust free. Tom Robl: All of the mining companies they’ve shown it to are really happy with it. In the mining environment, when something needs to be fixed or stabilized, it’s got to be done quickly. It’s almost a crisis situation, like a shock-damaged structure. Peter Mills: These products are unique, not only in America, but I believe in the world, too. So wherever you could see a need for structural support effectively immediately, these products will fit the bill. VO: Fast set times and extreme strength come from fly ash—a byproduct of coal combustion. Rodney Andrews: CAER has the largest program in the United States looking at the use of coal combustion, gasification byproducts. These are things like fly ash… Rather than putting them in a landfill or into a pond we try to find ways to have these used…as sustainable construction materials. They work very well as replacements for Portland cement. More recently, the work’s been focused on using them to make specialty concretes, low-energy cements, fast-setting cements, and what are called calcium-sulfoaluminate cements, which are a completely different chemistry than Portland. VO: Concrete typically contains crushed stone, sand, and Portland cement. Tom Robl: It’s called a pozzolan…and what it does it makes the concrete stronger, it makes it more durable, and it makes it more resistant to certain kinds of chemical attacks. You can’t make high-performance concrete without a pozzolan. The number one role of fly ash is to replace Portland cement. In my opinion, replacing Portland cement and displacing it represents the greatest engineering materials challenge of our time. Portland cement is the third largest emitter of carbon dioxide on the planet. What we’re doing here with CSA, these calcium sulfoaluminate-based materials… they can be formulated by using coal-combustion byproducts at carbon emission levels a third that of Portland cement. We were able to take a system that is fundamentally different from Portland, and use a whole different set of chemical tools in engineering this material. Instead of forming a gel, they form an actual crystal. You can use nucleating agents… things that force the crystal to form faster. That’s one of the key things that we’ve done. Minova handled all the patent work. They simultaneously filed patents in London and Washington D.C. Peter Mills: We need to protect our very valuable intellectual property. Bob Jewell: This project has embodied research. What I love about research, you can sit down with an idea or concept and you get to follow it through. And every step poses new problems, new questions, and allows you to come up with these new answers. From concept to trial in the lab to field testing to actual product—it’s pretty amazing and unique. Tom Robl: We’re actually looking at some derivative technologies... If not this exact formulation, probably something that is the daughter or son of—at least grandson—of this. So we view this as the beginning of a fruitful and hopefully very lucrative collaboration between Minova and the University of Kentucky. 1