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' <br /> ' A. Inspection: Before placing concrete, inspect and coFnplete formwork installation, <br /> reinforcing steel, and items to be embedded or cast in. Notify other trades to permit <br /> ins#aliation of their work. <br /> ' B. General: Comply with ACI 3U4, "Guide for Measuring, Mixing, Transporting, and <br /> Placing Concrete,"and as specified. <br /> � C. Deposit concrete continuously ar in tayers af such thickness that no new concrete will be <br /> placec� an concrete that has hardened sufficiently ta cause seams or planes of weaicness. <br /> If a section cannot be placed contir�uously, provide constnxction joints as specified. <br /> , Deposit concrete to avoid segregation at its final Iocation. <br /> D. Placing Concrete in Forms: Deposit concrete in fo�rmms in horizontal layers no deeper than <br /> 24 inches and in a ma�er to avoid incIined construction joints. Where placement <br /> � consists of several Iayers, place each layer w�ile preceding layer is still plastic to avoid <br /> cold joints. <br /> , 1. Consolidate placed concrete by mechanical vibrating ec}uipment supplemented by <br /> hand-spading, rodd'vng, or tamping. Use equipment and procedures for <br /> consolidation of cancrete complying with ACI 309. <br /> � E. Placing Concrete Slabs: Deposit and consolidate concrete slabs in a continuous <br /> operation, within timits of consituction joints, until cocnpleting placement of a panel or <br /> section. <br /> � 1. Consolidate concrete during piacement operations so that cc�ncrete is thoroughly <br /> worked around reinforcement,other embedded items and into comers. <br /> 2. Bring slab surfaces to comect level with a stcaightedge and strike off. Use bull <br /> ' floats or darbies to smooth swface free of humps or hollows. Do not disturb slab <br /> surfaces prior to beginning finishing operations. <br /> 3. Maintain reinforcing ia proper position on chairs during concrete placemen�. <br /> ' F. Hot-Weather Placement: When hot weather conditions exist that woulci impair quality <br /> and strength of concrete,place concrete complyin�with ACI 305 and as specified. <br /> � 1. Cool ingredients before mixing #o maintain concrete temperature at time of <br /> placement to below 90 deg F (32 deg C). Mixing water may be chilied or <br /> chopped ice may be used to control temperature,provided water equivalent of ice <br /> � is ca.Iculated to total amaunt of mixing water. Using liquid nitrogen to cool <br /> concrete is Contractor's option. <br /> 2. Cover reinforcing steel with water-soaked burlap if it becomes too hot, so that <br /> steel temperature will not exceed the ambient air temperature imraediately before <br /> , embedding in concrete. <br /> 3. Fog spray forms, reinforcir�g steei, and subgrade just before piacing concrete. <br /> Keep subgrade moislure uniform without puddles or dry areas. <br /> ' 4. Use water-reducing retarding admixture when required by hig}x temperatures,low <br /> humidity,or other adverse placing conditions,as acceptable to Arciutect. <br /> 3.6 FINISHING FORMED SURFACES <br /> � A. Rough-Formed Finish: Provide a rough-formed finish on formed concrete surfaces not <br /> exposed to view in the finished Work ar concealed by other construction. T'his is the <br /> ' concrete svrface having texture impacted by form-facing material used,with tie holes and <br /> defective areas repaired and patched,and fins and other projections exceeding 1/4 inch in <br /> height rubbed down or chipped off. <br /> � B. Smooth-Formed Finish: Provide a smoo�-formed finish on forfned concrete surfaces <br /> exposed to view or to be covered with a coating material applied directly to concrete,or a <br /> covering material applied directly to concrete,such as waterproofing,dampproofing, <br /> � CONCRETE Page 5 of 8 <br />