Many U.S. Army facilities are made of common construction materials such as concrete masonry.
These materials are highly porous, making them susceptible to moisture intrusion and associated
waterborne particles. Such particles can cause corrosion of the reinforcement, and promote mold and
mildew growth in confined spaces. Waterproofing solutions exist but are expensive, and most require
maintenance over the life of the structure. This problem affects all military construction where water
migration through masonry impacts the structure’s life and durability, especially facilities near coastal
zones.
A hydrophobic admixture in concrete can prevent moisture migration and reduce the costs of
maintenance and repairs associated with moisture-induced problems. The admixture reduces the water
absorption properties of cementitious products such as block, mortar, and grout. As a result, the
additive reduces the mold potential and protects concrete masonry walls from deterioration due to
water penetration. This study evaluates the hydrophobic admixture by testing masonry walls, with and
without the hydrophobic additive, exposed to a simulated wind-driven rain for a period of four hours.
Results indicate that the hydrophobic additive does increase the time of wetness and decreases the
amount of moisture that penetrates the wall.
Key words: Hydrophobic, masonry, admixture, corrosion, waterproofing, water, concrete, block, ASTM E 514