We're replacing a concrete pad for a storage tank that contains hydrochloric acid. The pad is deteriorated badly due to spillage and the new pad will also be exposed to spills. Is there a special concrete we can use or a protective sealer?
A sealer alone won't do the job. You'll probably need to use a protective membrane. Bituminous materials or sand-filled epoxies, polyesters, or polyurethanes can be used in a barrier system. It's also a good idea to use low permeability concrete so that even if the membrane fails, deterioration will be slowed. The concrete should have a low water-cement ratio (0.40 or lower). Use silica fume as an admixture to lower permeability even more. It may help to use a siliceous aggregate (gravel) rather than a calcareous one (crushed limestone). If the pad will be exposed to abrasive wear, you may also need to protect the membrane. Repair contractor Bob Schoenberner described a job where a 1_4-inch-thick fiberglass-reinforced asphaltic membrane was installed first to protect the concrete from acid attack. Then the membrane was topped with a 1 1/2-inch layer of fiber-reinforced, acid-resistant potassium silicate concrete. See Concrete Construction magazine, February 1989, page 95, for further details. For more information about protective coatings, see ACI 515.1R-79 (85), "Guide to the Use of Waterproofing, Dampproofing, Protective, and Decorative Barrier Systems for Concrete." This 44-page report costs $33.75. Order it from the American Concrete Institute, P.O. Box 19150, Detroit, MI 48219.