Hi, I stand before you today, readers, overwhelmed and embarrassed because I’m going to skip a written rule that I expressed in my last article: “My name is Rodolfo and I have the intention of creating a building with different materials and building systems, but all of them have to have been already used in some construction, if not, How will I know that it really works?”… Do you remember? I regretted to have written it, because I had discovered a very special place with a very special material… that you don’t want to miss!
A childhood friend is the guilty for all this, I not, of course, she is like Mafalda in various senses, as you know, Mafalda is a famous character of an Argentine cartoonist… is he called Quino? Anyway, the fact is that over the years she became an architect of weapons take and totally identifiable with the character of character… I do not recommend that you face it! Her name is Cristina and once took me to a place impressive where in addition to studying, they want to improve the world, this site is the M.I.T. (Massachusetts Institute of Technology) and there is where I discovered recently that they try to vary the concrete to a… Ecological concrete.
Ray and Maria Stata Center, Cambridge, Massachusetts, Estados Unidos
- Third Stop: The Ecological Concrete.
The concrete has very bad reputation, especially among the environmentalists, but it is not quite true that it is so bad. I do not defend what is, but i defend what it does. It is, without doubt, the material most used in the world. So much, that the Greeks already knew their existence in the year 500 BC (you did not know, huh?). The building of today is not understand structurally and aesthetically without it.
With the mixture of water, sand, gravel and cement is obtained concrete, it can add additives and different elements to vary its features and it make more durable, lighter, heavier… A fundamental quality is the solidification of the material: its components are mixed with the required dosage and after a few minutes starts to solidify, finally it takes the form with which we mold it and one strength and durability that will not make more than increase.
The main problem is that the concrete produces a tenth of the greenhouse gases generated by the industry and that, of course, this contributes to global warming, but we have to “the guys from the M.I.T.” as I affectionately call them. Recently I was invited to his laboratory and they taught me some tests and theories with which they are intend to manufacture a ecological concrete which will reduce the carbon footprint, it is fantastic!
Construction of bridge about the Almonte river, Cáceres (Spain)
- Pellenq and the “magic ratio”
The cement, a key element of the concrete, it is make by cooking to 1500 degrees centigrade of the limestone (rich in calcium) and the clay (rich in silica). These materials vary but the proportions of calcium and silica is must keep, this produces a paste that it is called Clinker. The most of the greenhouse gases produced by the material are responsability of the descarbonization of the calcium and the silica.
Well, Rolan Pellenq (MIT researcher) and the professors Krystyn Van Bliet, Franz-Josef Ulm, Sidney Yip and Markus Buehler is describe in the journal Nature Communications a new analysis that suggests that the reduction in the proportion of silica and calcium would lower CO2 emissions and they would also produce a better and stronger concrete.
Pellenq and his boys discovered that the ratio between the calcium and the silica could be reduced from the 1´7, which it is the accepted standard, to 1´5 and it achieve the twice of the resistance of normal cement. With this low ratio, the crystalline structure well ordered progresses into a disordered structure vitreous, this produces that the material improve their mechanical strength and eliminate the residual stresses, with this it is make more resistant to fracture. This ratio, the 1´5, it is called “the magic ratio” for Pelleq.
We imagine now that in the tallest building in the world, the Burj Khalifa, which it is located in Burj Dubai, (if you have not gone yet, I recommend) it would have used this new “concrete ecological”, as it did used 330,000 cubic metres of concrete which equals to 792,000 tons (around of nine million of people: I know cities more small) this would mean that instead of expell 316.800 tons of CO2 only would be expelled 158,000 tons.
In short, already I have ordered the staff of M.I.T. that they have to finish their experiments, because I want to use this concrete in my future construction. Bye bye.
Origen: The Ecological Concrete