I love concrete as a material - you can do some truly amazing things with it - Tadao Ando's buildings, often odes to concrete, remain an inspiration to me. But it has huge carbon emission problems. And it is not recyclable. Use once and throw it away where it ends up in landfill. At least with steel once it is metal you can recycle it as much lower energy cost. But even steel is twice as carbon intensive per tonne than concrete... luckily you need a lot less of it in buildings.
In most buildings, once you remove foam insulation materials, concrete remains the largest source of carbon emissions.
The Guardian article Concrete is the most destructive material on earth
might be overstating it. We need a low carbon concrete.
This book - ICE Themes Low Carbon Concrete
is a scholarly work that covers the ongoing research on low carbon concrete. It is comprehensive. Examples of solutions it covers include: -
- Sewerage Sludge Ash in Cement Based Products- Ceramic Tiles as replacement material in Portland Cement- Potential uses of geopolymer in cements- The affect of additives on carbon take-up during curing
There are a lot of scholarly materials on low carbon concrete but other than fly-ash concrete there are not yet enough options to either replace concrete, or reduce the carbon intensity of concrete. It really is up to designers and specifiers to avoid the overuse of concrete in buildings.
And that's a shame as Ando's buildings are sublime. He somehow turns the densest and darkest of materials into a homage to light and space.