MIT Researchers Discover Why Concrete Breaks Down
The old saying “step on a crack, break your mother’s back” may not apply to sidewalks for much longer now that MIT researchers have figured out why concrete breaks down. As a result of the discovery, structures like buildings, bridges, and yes, sidewalks, could last for hundreds of years longer than they currently do. A nuclear waste container built to last 100 years could, for example, last 16,000 years.
- » See also: Best Counterargument to Price on Carbon Hurting Jobs?
- » Get CleanTechnica by RSS or sign up by email.
According to MIT professor Franz-Josef Ulm, creep (the process that create cracks) is created when calcium-silicate-hydrates (CSH) rearrange at the nano scale. When mixed with water, CSH particles change in density from 64% to 74%. By adding silica fumes–a waste product from aluminum production–to concrete, overall density can increase to 87%. That’s a change that could eventually lead to longer-lasting, lighter structures.
If Ulm’s theories are put it into practice, the concrete industry and the planet could benefit immensely. 5 to 8% of all manmade CO2 comes from manmade concrete construction, so any reduction in the need to produce more of the stuff would slow global warming. And with twenty billion tons of concrete churned out annually, there’s plenty of room to cut down on production.
another nitpick: the 5-8% figure is usually attributed to the production of cement, not concrete itself. So really, an improved method for producing cement is needed.
The original item from MIT.
http://web.mit.edu/newsoffice/2009/creep-0615.html
Seems the 16000 year number comes from mathematical modelling.
The information is not adequate, and does not highlight the breakthrough of the MIT researcher. It needs clarifications.
“Seems the 16000 year number comes from mathematical modelling.”
Bull hooey! My pappy’s great-great-great-great-great-great-grande-great-grate-gyrate-great-grand-father had that study passed down to him from his great-great-great-great-great-great-grande-great-grate-gyrate-great-grand-father!
I finally saw degradation in the sample so I reported it as it was my and my family’s sworn duty to the tribe, the elders, and the shaman.
[...] is estimated to account for about 5% of all carbon dioxide emissions from human activity, with concrete accounting for about 8% overall. Though rubber surfaces do involve some greenhouse gas in the manufacturing process, [...]
Scientifically we can’t judge on this article if we didn’t see any results and trends, like what is the becoming compressive strength,expansion test during a certain period of time with different % of silica fume mixed with the concrete. Also what is the future of the silica fume after being solidified inside the concrete, is there any study done concerning the permeability of the silica and its content such as heavy metals when they are facing acidic environment like acid rain or in Alkali environment.
this is landmark achievement by researchers.i would
add it further by further curbing global warming .
csh particle can be neutralize by adding gravel and sand process in bricks kiln and closing it mouth.then adding in concrete.moreover collecting the smoke from all industries and adding in concrete alongwith lime then that would also reduce global warming.
ur sincerely
kashif