13 Sept 2024. Present: Julie, Ester, Bob, Franziska, Carles, Simon, Hiyala.
Concrete is the 2nd most used substance . (water is the first)
Concrete is Aggregate + Cement
The concrete making process has multiple sources of CO2 but
Calcium Carbonate + Heat => Lime + CO2
https://en.wikipedia.org/wiki/Environmental_impact_of_concrete
Concrete is responsible for 8% of global emissions.
900kg CO2 is released for 1 tonne of cement produced.
Demolition and decaying concrete wastes the CO2 that was already released into the atmosphere through the manufacturing process.
Global demand for cement (which hardens into concrete) is expected to increase 48% from 4.2bn to 6.2bn tons by 2050
Several approaches to reducing CO2 in production.
This is not an exhaustive list!
Using AI and IOT to better mix / test the concrete. Berlin based company called Alcemy
Self Healing concrete. (some material that Hydrates on contact with water.) See Mimicrete
Use Bacteria so no Portland cement is used. See Biozeroc
Construction is conservative industry. Regulations e.g. BSA500 specify certain proportion of cement in concrete. And the amount of self healing allowed is limited.
See Materialism Podcast Ep73: Bio Inspired Concrete.
Use Carbon Capture and Storage (CCS) where the cement is created.
Direct Air Capture (DAC) can be used to extract CO2 from the general environment (e.g. ClimeWorks) but it can also be done where the CO2 is created e.g. Heidelberg Materials use Carbon Capture and Storage (CCS) when the cement is created in Brevik, Norway.