Hello, I hope everyone is doing well. I’ve been busy with the holidays but I’m finally going to get back to my blogging and will hopefully maintain my weekly posting schedule this time around. Today, I would like to talk about some research on applications of shape memory alloy (SMA) in concrete infrastructure rehabilitation being done at University of Houston and Qatar University.
SMA’s are metal alloys that can be deformed and then return back to their original shape when re-heated. In this case, researchers are testing the usage of SMA’s in a rod that would be wrapped around concrete beams or columns. Their ability to deform, then return to their original shape, would apply an active confinement pressure. The design/usage of SMA’s would perform the function of current fiber-reinforced polymers (FRP’s); however, FRP’s only apply a reactive confinement pressure. The confinement pressure provided by the SMA’s would, in theory, further reduce long-term deterioration and degradation.
The researchers will focus on determining the best available material for concrete columns and beams. There are three types of metal alloys being tested. The alloys that are most commonly available are the nickel/titanium alloys, referred to as binary alloys. Ternary alloys include a third metal in addition to the binary alloy metals. A third option are the iron- and copper-based alloys, which are generally less expensive. Since binary alloys require constant heating to have continuous active confinement pressure, the scientist are focusing their studies on a Ternary alloy using Niobium and Iron/Copper alloys.
I believe the application of SMA’s in this application could improve infrastructure rehabilitation. However, there are some concerns I have. I think we need to see definitive proof with testing that, by adding the active confinement pressure, we effectively improve the serviceablity life of the infrastructure. The other concern is that we don’t know how much the rods will expand due to creep – especially since the rods will be continuously loaded with an outward force and have already been deformed to a previously outward deformed shape.
What is your opinion on this application for shape memory alloys? Do you think it will be effective and practical for concrete infrastructure rehabilitation? If you enjoyed reading, like the post and share it with your friends. Thanks for your time and have a good week!
“Shape Memory Alloys Could Bring Stabilizing Force To Concrete Infrastructure”, David Hill, Civil Engineering Magazine, June 2014
“Shape Memory and Palladium Iron Alloys”, taboodada.wordpress.com/2011/03/31/41/, March 31, 2011