I think there is a fair amount of interest in pozzolana type cements because it's becoming apparent that portland cement + rebar has a finite life.
> sand from different geologic deposits can show vastly different results
That's the other bugaboo about portland cement, Aggregate expansion/alkali-silica reaction/concrete cancer. They used the wrong type of aggregate and dune sand in the old foundation of my house (rental not my problem unless I'm in it during the next earthquake). So now it's crumbling.
Granted if you keep reinforced portland cement dry, it's fine. Otherwise eventually it'll fail.
> sand from different geologic deposits can show vastly different results
That's the other bugaboo about portland cement, Aggregate expansion/alkali-silica reaction/concrete cancer. They used the wrong type of aggregate and dune sand in the old foundation of my house (rental not my problem unless I'm in it during the next earthquake). So now it's crumbling.
Granted if you keep reinforced portland cement dry, it's fine. Otherwise eventually it'll fail.