specifications - FAACO - Federal Aviation Administration Contract ...

3.18 ALUMINUM OR STEEL IN CONTACT WITH OR EMBEDDED IN CONCRETE:FTWIC-2235June, 2009A. Where aluminum anchors, aluminum shapes, or aluminum electrical conduits areembedded in concrete, paint aluminum contact surfaces with zinc chromate primer.Allow the paint to thoroughly dry before placing the aluminum in contact with theconcrete.B. Paint steel or other ferrous metal to be mounted on or placed in contact with dry/curedconcrete, and coat in accordance with Section 09905, PROTECTIVE COATINGS priorto installation.3.19 CURING REQUIREMENTS:A. GENERAL:Give careful attention to proper concrete curing. The curing methods shall be wet curing,sheet materials conforming to ASTM C-171, or membrane curing compound conformingto ASTM C-309. Membrane curing is not permitted on surfaces to be rubbed or onsurfaces to which additional concrete, is to be applied. Unless the curing method isspecified otherwise, select the appropriate curing method.B. LENGTH OF CURING PERIOD:1. A "curing day" shall be any day on which the atmospheric temperature taken inthe shade, or the air temperature adjacent to the concrete, remains above 50degrees F for at least 18 hours.2. Cure concrete for a period of seven (7) consecutive days. In cold weather, whencuring may be retarded, extend this period to seven (7) "curing days", up to alimit of 14 consecutive days.C. WET CURING:1. Immediately following the finishing operations, cover concrete slabs, includingroof slabs, with wet cotton mats or with a temporary covering of canvas orburlap. Keep thoroughly wet for a period of four (4) curing days after theconcrete is placed. The covering shall be held in direct contact with the concrete.A temporary covering shall be required when the size of slab, size of mats, orother factors dictate that the mats cannot be placed immediately after thefinishing operations without marring the finishing of the slab.2. Water used for curing shall be free from injurious amounts of oil, acid, alkali,salt, or other deleterious substances.3. Canvas or burlap covering material shall weigh not less than twelve (12) ouncesper square yard. Place the sections with a lap at the edges of at least 8". Saturatecover material with water previous to placing. Keep saturated as long as itremains in place. Use care in the placing of the cover material to prevent marringthe concrete surface.03300-27