Loxon
I agree with the original reply, Loxon Masonry would be the best for this application. It is a polymer base, not organic, that is not affected by a high Ph that new masonry has. It's considerabally more expensive than other primers, but its worth it since the original base coat is the most important. Just be sure to pressure wash the surface to get the dust off as well as the small specs of mortar adhering to it after it was completed.