Since 2009, the PCA has supported the Concrete Sustainability Hub at MIT. Recent news from MIT provides some interesting results of research into the formulation of cement. Many people know that the reaction of calcium, silica, and water in cement provides most of the strength we see in concrete. The news reports on the latest findings provide that research into the ratio of calcium to silica in cement has revealed that the optimum ratio is closer to 1.5 as opposed to the ratio of 1.7 more commonly used in industry. This reduction in the ratio of calcium in the mix means a reduction in CO2 released during production. More importantly, the change in C:S ratio provides for a greater mechanical strength and resistance to fracture. Additional research is anticipated in this area, but this research shows that much remains unknown about many of the fundamentals of how cement works….