PURPOSE: To provide a mortar with good water repellency, excellent adhesion and superior compressive strength by using the additive comprising a water repelling agent, a synthetic latex, an alkalnolamine and a set retarding agent.
CONSTITUTION: A water repelling agent (A) is produced by selecting a fatty acid (salt) such as a stearate dispersion liquid. Then a synthetic latex (B) is obtained by selecting an acrylic latex or the like. Furthermore, an ethanolamine and a triisopropanolamine are mixed at a weight ratio of 5-1:1-5 to produce an alikanolamine (C). Then a set retarding agent (D) is produced by selecting a lignosulfonate, a polysaccharide, a hydroxycarboxylic acid and their mixture. Then an additive is produced for a masonry block cement compound by mixing 40-75 wt.% of the component A, 5-35 wt.% of the component B, 0.5-15 wt.% of the component C, and 5-25 wt.% of the component D.