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<br />Copyright 2004 AIA <br /> <br />MASTERSPEC Short Form <br /> <br />05/04 (R 05/06) <br /> <br />K. Comply with PCI MNL 117 for hot- and cold-weather concrete placement. <br /> <br />L. Identify pickup points of architectural precast concrete units and orientation in structure with <br />permanent markings, complying with markings indicated on Shop Drawings. Imprint or <br />permanently mark casting date on each architectural precast concrete unit on a surface that will <br />not show in fmished structure. <br /> <br />M. Cure concrete, according to requirements in PCI MNL 117, by moisture retention without heat <br />or by accelerated heat curing using low-pressure live steam or radiant heat and moisture. Cure <br />units until compressive strength is high enough to ensure that stripping does not have an effect <br />on performance or appearance of fInal product. <br /> <br />N. Discard and replace architectural precast concrete units that do not comply with requirements, <br />including structural, manufacturing tolerance, and appearance, unless repairs meet requirements <br />in PCI MNL 117 and Architect's approval. <br /> <br />2.7 FABRICATION TOLERANCES <br /> <br />A. Fabricate architectural precast concrete units straight and true to size and shape with exposed <br />edges and comers precise and true so each fmished panel complies with PCI MNL 117 product <br />tolerances as well as position tolerances for cast-in items. <br /> <br />2.8 FINISHES <br /> <br />A. Panel faces shall be free of joint marks, grain, and other obvious defects. Comers, including <br />false joints shall be uniform, straight, and sharp. Finish exposed-face surfaces of architectural <br />precast concrete units to match approved [design reference sample] [sample panels] and as <br />follows: <br /> <br />1. Design Reference Sample: <Insert description and identify fahricator and code <br />numher of sample.> <br />2. PCI's "Architectural Precast Concrete - Color and Texture Selection Guide," of plate <br />numbers indicated. <br />3. As-Cast Surface Finish: Provide surfaces free of pockets, sand streaks, and honeycombs. <br />4. Textured-Surface Finish: Impart by form liners or inserts to provide surfaces free of <br />pockets, streaks, and honeycombs, with uniform color and texture. <br />5. Bushhammer Finish: Use power or hand tools to remove matrix and fracture coarse <br />aggregates. <br />6. Exposed-Aggregate Finish: Use chemical retarding agents applied to concrete forms and <br />washing and brushing procedures to expose aggregate and surrounding matrix surfaces <br />after form removal. <br />7. Abrasive-Blast Finish: Use abrasive grit, equipment, application techniques, and <br />cleaning procedures to expose aggregate and surrounding matrix surfaces. <br />8. Acid-Etched Finish: Use acid and hot-water solution, equipment, application techniques, <br />and cleaning procedures to expose aggregate and surrounding matrix surfaces. Protect <br />hardware, connections, and insulation from acid attach. <br />9. Honed Finish: Use continuous mechanical abrasion with fine grit, followed by filling and <br />rubbing procedures. <br /> <br />ARCHITECTURAL PRECAST CONCRETE <br /> <br />03450 - 7 <br />