High-quality acrylic latex paint works best on concrete blocks. The concrete should be thoroughly prepared to accept the paint for best results.
Prepping the concrete blocks is as important as the paint used on them. The entire surface to be painted should be washed with a solution of 1 cup of bleach and 1 gallon of water. Then it should be cleaned again with a non-residue cleaner. The concrete blocks will need at least 48 hours to dry after cleaning. Once dry, a masonry sealer should be used on the blocks and they should be allowed to dry. Once dry, apply a latex primer and paint. it is important to note that new concrete should be allowed to harden for a full 90 days before painting.