When conversation turns, as it frequently does these days, to carbon emissions and climate change, the question of concrete always arises.
As we all know, concrete is incredible stuff. It’s the most-used man-made product in the world with more than 30 billion tonnes produced annually. It’s hard to imagine where we would be without it.
But it’s also one of the most carbon-intensive manufactured products, generally acknowledged as being responsible for about 8% of anthropogenic carbon emissions. That’s a bit embarrassing if you’re a climate-conscious construction professional.
And that’s why reducing concrete’s carbon footprint is one of the most varied and ingenious areas of research in the industry today.
Some of the ideas are actually not that old: the substitution of blast furnace slag or fly-ash for cement in mixes goes back decades. But while it was hailed as a cost-saving solution in the 1990s, it’s a mainly a carbon-saving idea today. It just depends how you sell it.
In this issue of the magazine we look at a project to commercialise a method that accelerates natural geological processes to bond so much atmospheric carbon into a cement additive that the resulting concrete can absorb more carbon than it emits during production.
Sounds too good to be true? Maybe it is. But if it isn’t, the people developing it will soon be very rich!