How does concrete produce CO2

I think it's the process of making concrete powder.

Seems half the CO2 production come from burning lime to make clinker. Since concrete is heavy, lots of energy for transportation.

Don't forget disposal. Cracking broken concrete down to small enough chunks so that it can be lifted out and trucked away to someplace that will further break down those smaller chunks should/does take a lot of energy hence emissions.

craftsman wrote: ↑ Don't forget disposal. Cracking broken concrete down to small enough chunks so that it can be lifted out and trucked away to someplace that will further break down those smaller chunks should/does take a lot of energy hence emissions.

Unless it is built to last.

Amazingly, the Romans knew how to make concrete and make it last. The dome of the Pantheon in Rome (and the rest of the building) is standing after 1,900 years. The roof is apparently graded between fine/light and heavy/coarse.

Less spectacular are Roman breakwaters. Volcanic ash was apparently one of their secret ingredients.