A new molecular analysis of concrete’s structure leads to a new formula that would reduce its greenhouse gas emissions and produce better, stronger concrete.
Concrete is a leading contributor to global warming, producing between 5 to 10 per cent of industry-generated greenhouse gas emissions. With urbanisation expected to grow exponentially over the coming decades, there is an urgent need to reduce the carbon emissions of the world’s most used construction material.
Concrete is made from sand, gravel, water and cement. By undertaking the most detailed molecular analysis yet of its complex structure, a team of MIT researchers discovered that reducing the ratio of calcium to silicate in cement from the conventional 1.7 down to 1.5 would produce cement that has two times the mechanical strength of normal cement and is also more fracture-resistant.
The new formula also promises to reduce carbon dioxide emissions by as much as 60 per cent because it requires less calcium in the cement mix, explains MIT senior research scientist Roland Pellenq.
So far, the work has remained at the molecular level of analysis. “Next, we have to make sure these nanoscale properties translate to the mesoscale” — that is, to the engineering scale of applications for infrastructure, housing, and other uses,” says Pellenq.