A new building material developed at Empa is about to be launched on the market: “memory-steel” can not only be used to reinforce new, but also existing concrete structures.
When the material is heated (one-time), prestressing occurs automatically. The Empa spin-off re-fer AG is now presenting the material with shape memory in a series of lectures.
So far, the steel reinforcements in concrete structures are mostly prestressed hydraulically. This requires ducts for guiding the tension cables, anchors for force transfer and oil-filled hydraulic jacks. The space requirements of all these apparatuses created the geometric framework conditions for every prestressed concrete structure; the strengthening of older structures therefore sometimes fails due to the high space requirements of this proven method.
In around 15 years of research work, experts from Empa and re-fer AG have now brought an alternative method to series production readiness: shape memory alloys based on iron, which contract during heating and thus permanently prestress the concrete structure. Hydraulic prestressing can thus be avoided – it is sufficient to heat the steel shortly, for example by means of electric current or infrared radiators. The new building material will be marketed immediately under the name “memory-steel”. Several pilot projects, such as the reinforcement of various reinforced concrete slabs, have already been successful.
Development of memory-steel
The development of memory-steel began in the early 2000s. In the previous decades, Empa had already pioneered the strengthening of concrete with carbon fibre reinforced polymers (CFRP). This led to the idea of using shape memory alloys for prestressing concrete. Initial tests with nickel-titanium alloys were positive. However, the material known from medicine is far too expensive for use in the construction sector. In 2009, Empa researchers succeeded in developing an iron-based shape memory alloy, which they also patented. In 2012, researchers around Julien Michels finally founded the company re-fer AG; Michels has been CEO of the young company ever since.
New opportunities for old buildings
Memory-steel should first of all be used for the strengthening of existing buildings. As soon as, for example, new windows, doors or lift shafts are installed in the concrete structure of an old building, a new reinforcement of the load-bearing structure is often unavoidable. In industrial buildings, the load-bearing capacity of an old suspended slab sometimes has to be increased. Thanks to memory-steel, such tasks can now also be easily solved in confined spaces: Either a strip of special steel is fastened under the ceiling using dowels and then heated with electricity or an infrared radiator. Alternatively, the reinforcement can also be set in concrete: First a groove is milled into the surface of the concrete slab, then a ribbed reinforcement bar made of memory-steel is inserted into the groove and filled with special mortar. Finally, the profile is heated with the aid of direct current and thus prestressed. Another variant is to embed the reinforcement bar in an additional shotcrete layer.
Precast concrete elements with special geometry
In the future, memory-steel could also be a proven method for manufacturing precast concrete parts with a previously unknown geometry. The hydraulic prestressing used up to now creates friction in curved structures, which greatly limits the use of this method. With a memory-steel profile embedded in concrete, highly curved constructions are now also possible: when heated, the profile contracts uniformly over its entire length without friction losses and transfers the stress to the concrete.
Market launch of memory-steel
The ready-to-install memory-steel profiles are manufactured by Voestalpine Böhler Edelstahl GmbH & Co KG in Austria. The company is also working with re-fer and Empa to further develop the composition of the alloy.
The new building material memory-steel will be presented to interested building experts and architects during four technical seminars. Contact persons include experts from re-fer, Empa researchers, concrete experts from Sika AG and concrete profile manufacturer Stahlton AG.
The Latest on: Memory-steel
via Google News
The Latest on: Memory-steel
- Tommy Hilfiger Stainless Steel Memory Steel Bangle 2780250 on August 10, 2019 at 10:25 am
Interest-free payment plans that allow you to spread the cost over equal monthly payments. Just select Openpay at the checkout, on purchases between £30.00 and £280.00. There are no long forms to ...
- Memory steel—a new material for the strengthening of buildings on October 24, 2018 at 4:20 am
A new building material called memory steel, developed at Empa is about to be launched on the market. The material can be used to reinforce new and existing concrete structures. When the material is ...
- Memory-steel -- A new material for the strengthening of buildings on October 23, 2018 at 7:18 am
The new building material will be marketed immediately under the name "memory-steel". Several pilot projects, such as the reinforcement of various reinforced concrete slabs, have already been ...
- memory-steel - a new material for the strengthening of buildings on October 23, 2018 at 4:27 am
A new building material developed at Empa is about to be launched on the market: "memory-steel" can not only be used to reinforce new, but also existing concrete structures. When the material is ...
- She started acting at 88; 4 years later, she's recognized everywhere for 'Black Panther' on March 23, 2018 at 9:10 am
Dorothy Steel, 92, starred as a merchant tribe elder in the blockbuster film, "Black Panther." (Photos courtesy of Cindy Butler and Matt Kennedy)[/caption] Dorothy Steel's mind was made up. She had ...
- She started acting at 88. Four years later, she’s recognized everywhere for ‘Black Panther.’ on March 23, 2018 at 5:35 am
Dorothy Steel’s mind was made up. She had only been acting for three years and didn’t want to audition for some “comic strip” movie she had never heard of. At 91, Steel told herself there was no way ...
- iPhone X first impressions: The 10 year itch on October 30, 2017 at 10:08 pm
If you thought the change from a physical key to a touch-sensitive one a few years back was jarring to your muscle-memory, steel yourself for an even bigger evolution. Still, there are really only ...
- FIRST LOOK: You’ll forget you’re in a mall at Cooper’s Hawk on April 19, 2017 at 9:15 am
Palm Beach County has its first Cooper’s Hawk — a three-in-one dining vibe that is both luxurious and casual. If you walk into the modern-day wine-tasting experience, you’ll forget you’ve been ...
- NEW Made in USA MemoryFlex™ Surgical Scissors on February 17, 2017 at 11:17 am
The memory steel patented technology provides the ultimate in durability. Memory steel flexes, maintaining a high sheer bias on the cutting edge and enabling the scissors to cut all the way to the tip ...
via Bing News