Can concrete be green?

Science topics February 2013

Consumption of concrete currently stands at three tonnes per person per year, making it the world’s most used manufactured material, and this figure continues to rise, fuelled by emerging countries. It behaves like liquid rock at ambient temperatures, making it uniquely straightforward to use and therefore difficult to replace. In France more than 80% of our buildings are made of concrete.

Its generalized use is not without impacts, for example on CO2 emissions, mainly due to the manufacture of cement, or the production of mineral wastes after deconstruction.

In this context, it is urgent to explore possible ways of producing green concrete. First, IFSTTAR is working on re-using demolition concrete as aggregates, developing ways of treating the concrete that trap the CO2 in order to improve the quality of the aggregates and the total life cycle emissions of the material. For the more distant future, IFSTTAR is also working on materials that can replace Portland cement, which is the “glue” used in present-day concrete.

Before these new cements and concretes can be used on an industrial scale they must be tested and accepted by the construction sector and demonstrate that they are compatible with modern construction techniques.