ALTERNATIVE TO PORTLAND CEMENT

Is there any practical and viable alternative to cement for multi-storey construction?
I read on some internet sites that fly ash and ground granulated blast furnace slag (GGBS) can replace cement to some extent.
How much is that true in practice?
Do GGBS last like cement?
And do GGBS have any toxic effects on human health?

i also have an interest in alternatives to portland cement. it is my understanding that these industrial byproducts can make a cement that has good psi and working characteristics. i believe that the issues arise from corrosion of imbedded steel, brittleness, and the heavy metal content of the dust from cutting or from the dry cement itself. probably lots of useless civil engineer data out there on various admixtures etc. also, the minnesota bridge collapse has been discussed in reference to fly ash failures.

the info i am looking for myself is on two common minerals in my area that were mixed at one time to make a type of cement - i remember reading about manganese ore being ground with something like shale (both local) but i have not been able to find the reference again. essentially a mineral cement, i would love to find the info again because i believe that it would make a sort of ultimate finish render for cob with a potential for less hydrophilic reaction than between cob and portland.