Concrete is the most used building material on Earth, and the part of it that does the heavy lifting is clinker, the fiercely heated ingredient that makes cement set. The Irish company Ecocem has spent more than ten years working out how to use far less of it. Their ACT cement replaces up to seventy per cent of the clinker with other mineral materials and limestone filler, and the clever part is what it does not require. It is a straight swap. No new factory, no new mixing plant, no retraining anybody on site, no change to the way a builder pours a wall on a Tuesday morning.
It has now had its proper examination. At Chessy, just outside Paris, a development called Parker and Baker has been built with ACT concrete in every single element, 147 apartments and four houses, around nine thousand cubic metres of it, batched in a mobile plant set up on the site itself. The finished structure carries a carbon footprint fifty five per cent lower than the conventional specification would have given it, and the buildings went up on an ordinary schedule with structural work finishing this September. Concrete produced using ACT has delivered excellent technical and environmental performance, says Olivier Guise, Ecocem's executive director for strategy, technology and development, while requiring no changes to the way the construction site operates. After more than forty pilot projects across Europe, that is the sentence that matters. The best inventions are the ones nobody has to be talked into using.
Our short take: announcement and project detail from Ecocem, with construction by Legendre.