The key to success when installing Adhesive products, is to achieve a good bond between the substrate, waterproofing membranes and tile adhesives. All manufacturers produce a range of primers for internal and external use.  Additive improves the strength of all powder adhesives, unnecessary in polymer fortified tile adhesives.

Old Stonemason ramblings:  All surfaces must be free of oil, paint, dirt/grime and dust.  Rain damaged slabs are to be ground to remove the laitance. A simple test is to pour a small amount of water on your floor.  If it doesn't absorbed, DON'T TILE.  Applying a primer, and using the same manufacturers adhesives, will give you a warranty.  It is a well-known fact that primers, apart from preparing the substrate for the adhesive, enhances better adhesion, better workability, easier notching, slightly more coverage and longer dry time.