Clay Masonry Units ASTM C 67, Standard Test Methods of Sampling and Testing Brick and Structural Clay Tile Mortar ASTM C 270, Standard Specifiion for Mortar for Unit Masonry ASTM C 91, Standard Specifiion for Masonry Cement ASTM C 109, Standard Test Method for Compressive Strength of Hydraulic Cement Mortars (Using 2in. or 50mm Cube Specimens) .