DESIGNMIX™ Professional-Grade Mortar Mix is a specially blended portland cement/lime based mortar mix that, when prepared properly, will result in a mortar that conforms to the Property Specification requirements of ASTM C270 (Standard Specification for Mortar for Unit Masonry). DESINMIX Professional-Grade Mortar Mix is appropriate for use with brick and concrete block. Properties and uses of mortar vary with specific mortar type.