Metal Finishing Guide Book

2012-2013

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Table I. Typical Physical Properties of Polymer Concretes Property Test Method Typical Value Tensile strength, psi (MPa) ASTM C 307 1,000-2,000 (7-14) Compressive strength, psi (MPa) ASTM C 039 10,000-12,000 (70-82) Flexural strength, psi (MPa) ASTM C 580 2,000-4,000 (14-28) Linear shrinkage, % ASTM C 531 < 0.1 Density, lb/ft3 ASTM D 792 130-145 (2.1-2.3) Water absorption, % ASTM C 413 < 0.1 Maximum use temperature, OF(OC) Continuous Intermittent ��� ��� 150 (66) 200 (93) Thickness, in. (mm) ��� 0.5 (13) The chemical resistance of polymer concretes is similar to their synthetic resin lining system counterparts as indicated in Table VII. materials available for protecting concrete and steel. The three basic types are glassfiber-reinforced sheet and molten asphaltics; sheet rubber, plastics, and elastomers; and reinforced and nonreinforced ambient-cured synthetic resin systems. Conspicuous by its absence from this list is protective coatings. This is not to say they can���t be used; however, 60 mils is usually considered to be a minimum acceptable thickness for a material to be considered a tank lining. If a coating can be economically applied (initial cost and longevity) to a minimum thickness of 60 mils, free of pinholes and holidays, and can resist the process chemicals and temperatures as well as physical abuse, consideration should be given to their use. Generally speaking, coatings are used for fume and splash protection and not necessarily for total immersion process applications. Asphaltic linings are equally appropriate for application to concrete and steel. The hot-applied, molten materials, as well as sheet stock can be used on concrete tanks. For steel tanks, glass-fiber-reinforced sheet is the most desirable. Both types of asphaltic linings, sheet and molten, are seldom, if ever, used without being further protected with a chemical-resistant brick lining. Without further protection from a brick sheathing, these linings can cold flow and be easily damaged from impact, abrasion, and thermal excursions. Masonry sheathings provide a rugged, chemical-resistant insulating barrier for protection of asphaltic as well as other types of linings. The physical properties and the chemical resistance of asphaltic linings are shown in Tables II and III, respectively. Adhesive-bonded sheet linings, such as various plasticized plastics, rubbers and elastomers are most commonly used for steel tanks. Successful applications have been made on concrete; however, it is not the most desirable substrate on which to bond and cure many of these systems. The physical properties and the chemical resistance of sheet linings are shown in Tables IV and V, respectively. Mechanically bonded rigid plastic linings for precast and poured-in-place concrete tanks are a relatively new concept. Instead of bonding with adhesives, this system utilizes anchor studs sonically welded to the back of the sheet for locking or mechanically bonding the sheet to the concrete. Ambient temperature-cured, spray- and trowel-applied synthetic resin lining systems are based on the following resins: furan, epoxy, polyester, vinyl ester, and urethane. These systems are entirely appropriate for application to steel and concrete. They have also been successfully applied to wood, certain plastics, and various 794

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