cement for DIY rocks

[justinl]

headaches...

Ive read through a bit of the literature online about making DIY rocks out of sand cement and rock salt, but what kind of cement should i be using? I know types I through III are fine, but that's American labelling. Canadians use types GU through HS... anyone know what type "I" is in Canadian?

oh and hardware stores don't stock rock salt after winter. if anyone has some that i can snag let me know