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CHAPEL HILL ORANGE COUNTY VISITORS BUREAU August 12, 2020 <br />308 WEST FRANKLIN, CHAPEL HILL, NC <br /> <br />MISCELLANEOUS CAST-IN-PLACE CONCRETE 033053 - 4 <br />2. Maximum Water-Cementitious Materials Ratio: 0.50. <br />3. Cementitious Materials: Use fly ash, pozzolan, ground granulated blast-furnace slag, and <br />silica fume as needed to reduce the total amount of portland cement, which would <br />otherwise be used, by not less than 40 percent. <br />4. Slump Limit: 4 inches (100 mm), 8 inches (200 mm) for concrete with verified slump of <br />2 to 4 inches (50 to 100 mm) before adding high-range water-reducing admixture or <br />plasticizing admixture, plus or minus 1 inch (25 mm). <br />5. Air Content: Maintain within range permitted by ACI 301 (ACI 301M). Do not allow <br />air content of trowel-finished floor slabs to exceed 3 percent. <br />C. Structural Lightweight Concrete Mix: ASTM C 330, proportioned to produce concrete with a <br />minimum compressive strength of 3000 psi (20.7 MPa) at 28 days and a calculated equilibrium <br />unit weight of 110 lb/cu. ft. (1762 kg/cu. m) plus or minus 3 lb/cu. ft. (48.1 kg/cu. m), as <br />determined by ASTM C 567. Concrete slump at point of placement shall be the minimum <br />necessary for efficient mixing, placing, and finishing. <br />1. Limit slump to 5 inches (125 mm) for troweled slabs and 4 inches (100 mm) for other <br />slabs. <br />2.8 CONCRETE MIXING <br />A. Ready-Mixed Concrete: Measure, batch, mix, and deliver concrete according to <br />ASTM C 94/C 94M[ and ASTM C 1116/C 1116], and furnish batch ticket information. <br />1. When air temperature is above 90 deg F (32 deg C), reduce mixing and delivery time to <br />60 minutes. <br />B. Project-Site Mixing: Measure, batch, and mix concrete materials and concrete according to <br />ASTM C 94/C 94M. Mix concrete materials in appropriate drum-type batch machine mixer. <br />1. For mixer capacity of 1 cu. yd. (0.76 cu. m) or smaller, continue mixing at least 1-1/2 <br />minutes, but not more than 5 minutes after ingredients are in mixer, before any part of <br />batch is released. <br />2. For mixer capacity larger than 1 cu. yd. (0.76 cu. m), increase mixing time by 15 seconds <br />for each additional 1 cu. yd. (0.76 cu. m). <br />3. Provide batch ticket for each batch discharged and used in the Work, indicating Project <br />identification name and number, date, mix type, mix time, quantity, and amount of water <br />added. Record approximate location of final deposit in structure. <br />PART 3 - EXECUTION <br />3.1 FORMWORK <br />A. Design, construct, erect, brace, and maintain formwork according to ACI 301 (ACI 301M). <br />DocuSign Envelope ID: 775B89AF-3514-4D9E-B148-2FDE4EFF16C2