MIT researchers may have found a way to produce “greener” cement, the emissions of which, compared to the commonly used mixture, would be reduced by more than half! Through detailed molecular analysis of the structure of concrete, the team has reached a conclusion that by reducing the amount of calcium silicate used in the mixture, not only would we get a material with lower CO2 emissions, but would also be able to produce better, stronger concrete.
A team of scientists led by senior research scientist Roland Pellenq, professors Krystyn Van Vliet, Franz-Josef Ulm, Sidney Yip, and Markus Buehle, found that changing the commonly used calcium-to-silica ratio of 1.7 to 1.5, produces a material two times the resistance of normal cement, in mechanical resistance to fracture. Besides improving mechanical strength of the material, this would also ensure “no residual stresses in the material”, which means the new type of cement would be more fracture-resistant.
The study was conducted in collaboration between MIT and Centre National de la Recherche Scientifique (CNRS), working in a joint laboratory at MIT called the Multi-Scale Materials Science for Energy and Environment. Their findings were published in the journal Nature Communications.
Learn more here http://newsoffice.mit.edu/2014/stronger-greener-cement-0925