Thanks for posting this Wil - and great research. The two issues I see are:
- Carbonation causes corrosion of the steel reinforcing, often necessitating patch repair or demolition, that will consume yet more cement with associated emissions. This is touched on, but not explored in depth - perhaps the model needs to limit the volume to the cover zone for the proportion of cement used in reinforced concrete.
- The model doesn’t account for the time value of eCO2 emissions, due to feedback loops of global warming some inflation rate needs to be applied to emissions made today that will be absorbed in the future. I’m not sure what the appropriate inflation rate is, but this could also be a way to account for timber and forestry practices impact on the carbon cycle.
Forgive me if I’ve missed anything in the literature.