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Gateway Park Center PERKINS+WILL <br /> 810495.00 <br />12/06/18 <br />033000-34 Cast-In-Place <br />Concrete <br />F.Placing Concrete on Steel Decks <br />1.Exercise care during concrete placement on steel decks to prevent <br />concentrated loads or high pile-ups of concrete and to avoid impacts <br />caused by dumping or dropping of concrete on steel decks. <br />2.Do not use buggies on unprotected areas of deck. If buggies are used to <br />place concrete, furnish and install planked runways to protect deck from <br />damage. <br />G.Placing Concrete at Construction Joints: <br />1.To secure full bond at construction joints, surfaces to receive concrete in <br />a subsequent placement shall be left in a roughened state or intentionally <br />roughened by raking while plastic or brushing and chipping immediately <br />after removal. <br />2.Before new concrete is placed in contact, surfaces of hardened concrete <br />already placed shall be thoroughly cleaned of foreign materials and <br />laitance. <br />3.At hardened concrete at joints where no bonding agents are used, <br />dampen concrete to achieve a saturated surface dry condition. Leave no <br />standing water. Place and vibrate concrete (slump 7 inches (180mm) or <br />greater) against horizontal joints. Place and vibrate flowing concrete <br />(slump 8 to 10 inches (200 to 250mm)) while maintaining pressure <br />against vertical joints by confinement. <br />4.At hardened concrete with joints not meeting conditions required for no <br />bonding agents, apply appropriate specified bonding agent for conditions <br />present including age and moisture per manufacturer’s specifications. <br />Place new concrete while the bonding agent is still tacky. <br />H.Floor Topping Slabs: <br />1.Place concrete topping slab to required lines and levels. <br />2.Minimum topping slab thickness is 2” (50mm). <br />3.Place dividers, edge strips and other items to be cast in place. <br />4.At all topping slabs, remove deleterious material before placing topping <br />slab. <br />5.At topping slabs placed directly against base slab, remove deleterious <br />material and dampen base slab with water immediately before placing <br />concrete. Leave no standing water. <br />6.Unless noted as a “bonded” topping slab on the Drawings, topping slabs <br />thinner than 4” (100mm) should be placed directly against dampened <br />base slab with no bonding agent. Topping slabs 4” (100mm) or thicker <br />should be placed on bond breaker consisting of two sheets of plastic film. <br />7.Where noted on Drawings as a “bonded” topping slab, broom/vacuum <br />clean unsealed surfaces or wire brush sealed or troweled surfaces to <br />expose bare rough surface. Then place approved bonding grout or epoxy <br />adhesive on the base slab per manufacturer’s instructions. <br />8.The topping mix shall have a maximum water/cement ratio of 0.45. <br />9.The topping mix shall have a maximum shrinkage of 0.04% in 28 days.