Depending on the chemical composition the structural parameters of the melilite vary in the range between gehlenite and mernite.Melilitic separation and melilite as a primary phase are very rare.
Blast furnace slags were partially replaced by artificial and natural pozzolanic materials, such as pozzolan , fly ash and zeolite,to produce alkali activated slag cement(AASC).
You touched a little bit on the sort of use of slag and replacing some of the cement, but there's some other stuff you guys have been doing that is really interesting around the building side of things.