>Everything else is hogwash. Ongoing maintenance is an important energy and money sink for any society. I find it doubtful that concrete (at least, the modern

>Everything else is hogwash. Ongoing maintenance is an important energy and money sink for any society. I find it doubtful that concrete (at least, the modern versions and usage of it) will be sustainable beyond the fossil fuel era, simply because it will be too expensive to maintain. EROEI for a given bit of infrastructure (ie how much energy is conserved or produced for a given energy expenditure in construction/maintenance) isn't as sexy, but it's just as much a thermodynamic constraint on sustainability as overusing the CO2 capacity of the oceans and atmosphere.