CSA-based cements, which I refer to as CSA cements, such as CTS’ Rapid Set cement, are true cements. They don’t need anything else, besides water, to work. CSA-based cements are added to sand, gravel and water to make concrete, exactly the same way portland cement is added to those ingredients to make concrete.
CSA cements are made using pure CSA clinker that is blended with portland clinker and fired in a kiln, similar to the way portland cement is fired in a kiln. Because the CSA and portland clinker are fired together at high temperatures, they combine to form CSA-based cements. There is no portland cement left after firing. It is chemically transformed into a rapid hardening CSA-based cement. This is NOT the same as simply dry blending portland cement and CSA-based cement together.
Another CSA-based product, Buzzi Unicem USA’s product called simply “CSA”, is NOT a cement. It is a CSA additive. It is designed to be, and MUST be, blended with portland cement. In this way it is similar to pozzolans like VCAS or metakaolin. Pozzolans must be blended with portland cement. They won’t do anything alone.
Note that another company, Ultimax, used to manufacture both a CSA cement and a CSA additive (Qwix). These products are no longer available.