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HomeMy WebLinkAbout03 30 00 Cast-in-Place ConcreteTHE KENT 03 35 00 - THE KENT Issue Date 05.09.18 CAST IN PLACE CONCRETE THE KENT SECTION 03 30 00 - CAST-IN-PLACE CONCRETE PART 1 - GENERAL 1.1 RELATED DOCUMENTS A. Drawings and general provisions of the Contract, including General and Supplementary Conditions and Division 01 Specification Sections, apply to this Section. 1.2 SUMMARY A. Section includes cast-in-place concrete, including formwork, reinforcement, concrete materials, mixture design, placement procedures, and finishes. B. Related Requirements: 1. Section 31 20 00 "Earth Moving" for drainage fill under slabs-on-grade. 2. Section 32 13 13 "Concrete Paving" for concrete pavement and walks. 3. Section 05 50 00 “Metal Fabrications” for abrasive nosings at concrete stair treads. 1.3 DEFINITIONS A. Cementitious Materials: Portland cement alone or in combination with fly ash; materials subject to compliance with requirements. B. W/C Ratio: The ratio by weight of water to cementitious materials. 1.4 PRE-INSTALLATION MEETINGS A. Pre-installation Conference: Conduct conference at Project site. 1. Before submitting design mixtures, review concrete design mixture and examine procedures for ensuring quality of concrete materials. Require representatives of each entity directly concerned with cast-in-place concrete to attend, including the following: a. Contractor's superintendent. b. Independent testing agency responsible for concrete design mixtures. c. Ready-mix concrete manufacturer. d. Concrete Subcontractor. e. Special concrete finish Subcontractor. 2. Review concrete finishes and finishing, cold- and hot-weather concreting procedures, curing procedures, construction contraction and isolation joints, and joint-filler strips, forms and form removal limitations, vapor-retarder installation, anchor rod and anchorage device installation tolerances, steel reinforcement installation, methods for achieving specified floor and slab flatness and levelness floor and slab flatness and levelness measurement, concrete repair procedures, and concrete protection. ACTION SUBMITTALS B. Product Data: For each type of product. THE KENT 03 35 00 - THE KENT Issue Date 05.09.18 CAST IN PLACE CONCRETE THE KENT C. Design Mixtures: For each concrete mixture. Submit alternate design mixtures when characteristics of materials, Project conditions, weather, test results, or other circumstances warrant adjustments. 1. Indicate amounts of mixing water to be withheld for later addition at Project site. D. Steel Reinforcement Shop Drawings: Placing Drawings that detail fabrication, bending, and placement. Include bar sizes, lengths, material, grade, bar schedules, stirrup spacing, bent bar diagrams, bar arrangement, splices and laps, mechanical connections, tie spacing, hoop spacing, and supports for concrete reinforcement. E. Construction Joint Layout: Indicate proposed construction joints required to construct the structure. 1. Location of construction joints is subject to approval of the Architect. F. Samples: For water-stops, vapor retarder. 1.5 INFORMATIONAL SUBMITTALS A. Qualification Data: For manufacturer. B. Material Certificates: For each of the following, signed by manufacturers: 1. Cementitious materials. 2. Admixtures. 3. Form materials and form-release agents. 4. Steel reinforcement and accessories. 5. Waterstops. 6. Curing compounds. 7. Bonding agents. 8. Adhesives. 9. Vapor retarders. 10. Joint-filler strips. 11. Repair materials. C. Material Test Reports: For the following, from a qualified testing agency: 1. Aggregates: Include service record data indicating absence of deleterious expansion of concrete due to alkali aggregate reactivity. D. Floor surface flatness and levelness measurements indicating compliance with specified tolerances. E. Field quality-control reports. F. Minutes of pre-installation conference. 1.6 QUALITY ASSURANCE A. Installer Qualifications: A qualified installer who employs on Project personnel qualified as ACI- certified Flatwork Technician and Finisher and a supervisor who is an ACI-certified Concrete Flatwork Technician. B. Manufacturer Qualifications: A firm experienced in manufacturing ready-mixed concrete THE KENT 03 35 00 - THE KENT Issue Date 05.09.18 CAST IN PLACE CONCRETE THE KENT products and that complies with ASTM C 94 requirements for production facilities and equipment. 1. Manufacturer certified according to NRMCA's "Certification of Ready Mixed Concrete Production Facilities." C. Testing Agency Qualifications: An independent agency, qualified according to ASTM C 1077 and ASTM E 329 for testing indicated. 1. Personnel conducting field tests shall be qualified as ACI Concrete Field Testing Technician, Grade 1, according to ACI CP-1 or an equivalent certification program. 2. Personnel performing laboratory tests shall be ACI-certified Concrete Strength Testing Technician and Concrete Laboratory Testing Technician, Grade I. Testing agency laboratory supervisor shall be an ACI-certified Concrete Laboratory Testing Technician, Grade II. 1.7 DELIVERY, STORAGE, AND HANDLING A. Steel Reinforcement: Deliver, store, and handle steel reinforcement to prevent bending and damage. B. Water-stops: Store water-stops under cover to protect from moisture, sunlight, dirt, oil, and other contaminants. 1.8 FIELD CONDITIONS A. Cold-Weather Placement: Comply with ACI 306.1 and as follows. Protect concrete work from physical damage or reduced strength that could be caused by frost, freezing actions, or low temperatures. 1. When average high and low temperature is expected to fall below 40 deg F for three successive days, maintain delivered concrete mixture temperature within the temperature range required by ACI 301. 2. Do not use frozen materials or materials containing ice or snow. Do not place concrete on frozen subgrade or on subgrade containing frozen materials. 3. Do not use calcium chloride, salt, or other materials containing antifreeze agents or chemical accelerators unless otherwise specified and approved in mixture designs. B. Hot-Weather Placement: Comply with ACI 301 and as follows: 1. Maintain concrete temperature below 90 deg F at time of placement. Chilled mixing water or chopped ice may be used to control temperature, provided water equivalent of ice is calculated to total amount of mixing water. Using liquid nitrogen to cool concrete is Contractor's option. 2. Fog-spray forms, steel reinforcement, and subgrade just before placing concrete. Keep subgrade uniformly moist without standing water, soft spots, or dry areas. PART 2 - PRODUCTS 2.1 CONCRETE, GENERAL A. ACI Publications: Comply with the following unless modified by requirements in the Contract Documents: 1. ACI 301. THE KENT 03 35 00 - THE KENT Issue Date 05.09.18 CAST IN PLACE CONCRETE THE KENT 2. ACI 117. 2.2 FORM-FACING MATERIALS A. Smooth-Formed Finished Concrete: Form-facing panels that provide continuous, true, and smooth concrete surfaces. Furnish in largest practicable sizes to minimize number of joints. 1. Exterior-grade plywood panels, suitable for concrete forms, complying with DOC PS 1, and as follows: a. B-B (Concrete Form), Class 1 or better; mill oiled and edge sealed. B. Rough-Formed Finished Concrete: Plywood, lumber, metal, or another approved material. Provide lumber dressed on at least two edges and one side for tight fit. C. Chamfer Strips: Wood, metal, PVC, or rubber strips, 3/4 by 3/4 inch, minimum. D. Form-Release Agent: Commercially formulated form-release agent that does not bond with, stain, or adversely affect concrete surfaces and does not impair subsequent treatments of concrete surfaces. 1. Formulate form-release agent with rust inhibitor for steel form-facing materials. E. Form Ties: Factory-fabricated, removable or snap-off glass-fiber-reinforced plastic or metal form ties designed to resist lateral pressure of fresh concrete on forms and to prevent spalling of concrete on removal. 1. Furnish units that leave no corrodible metal closer than 1 inch to the plane of exposed concrete surface. 2. Furnish ties that, when removed, leave holes no larger than 1 inch in diameter in concrete surface. 3. Furnish ties with integral water-barrier plates to walls indicated to receive damp-proofing or waterproofing. 2.3 STEEL REINFORCEMENT A. Reinforcing Bars: ASTM A 615, Grade 60, deformed. B. Plain-Steel Welded-Wire Reinforcement: ASTM A 1064, plain, fabricated from as- drawn steel wire into flat sheets. 2.4 REINFORCEMENT ACCESSORIES A. Bar Supports: Bolsters, chairs, spacers, and other devices for spacing, supporting, and fastening reinforcing bars and welded-wire reinforcement in place. Manufacture bar supports from steel wire, plastic, or precast concrete according to CRSI's "Manual of Standard Practice," of greater compressive strength than concrete and as follows: 1. For concrete surfaces exposed to view, where legs of wire bar support contact forms, use CRSI Class 1 plastic-protected steel wire or CRSI Class 2 stainless-steel bar supports. 2.5 CONCRETE MATERIALS A. Source Limitations: Obtain each type or class of cementitious material of the same brand from the same manufacturer's plant, obtain aggregate from single source, and obtain admixtures THE KENT 03 35 00 - THE KENT Issue Date 05.09.18 CAST IN PLACE CONCRETE THE KENT from single source from single manufacturer. B. Cementitious Materials: 1. Portland Cement: ASTM C 150, Type I/II, gray. 2. Fly Ash: ASTM C 618, Class F or C. C. Normal-Weight Aggregates: ASTM C 33, Class 3S coarse aggregate or better, graded. Provide aggregates from a single source with documented service record data of at least 10 years' satisfactory service in similar applications and service conditions using similar aggregates and cementitious materials. 1. Maximum Coarse-Aggregate Size: 1 inch nominal. 2. Fine Aggregate: Free of materials with deleterious reactivity to alkali in cement. D. Air-Entraining Admixture: ASTM C 260. E. Chemical Admixtures: Certified by manufacturer to be compatible with other admixtures and that do not contribute water-soluble chloride ions exceeding those permitted in hardened concrete. Do not use calcium chloride or admixtures containing calcium chloride. 1. Water-Reducing Admixture: ASTM C 494, Type A. 2. Retarding Admixture: ASTM C 494, Type B. 3. Water-Reducing and Retarding Admixture: ASTM C 494, Type D. 4. High-Range, Water-Reducing Admixture: ASTM C 494, Type F. 5. High-Range, Water-Reducing and Retarding Admixture: ASTM C 494, Type G. 6. Plasticizing and Retarding Admixture: ASTM C 1017, Type II. F. Water: ASTM C 94 and potable. 2.6 WATERSTOPS A. Flexible PVC Waterstops: CE CRD-C 572, for embedding in concrete to prevent passage of fluids through joints. Factory fabricate corners, intersections, and directional changes. 1. Manufacturers: Subject to compliance with requirements, available manufacturers offering products that may be incorporated into the Work include, but are not limited to the following: a. Sika Greenstreak. 2. Profile: Ribbed with center bulb. 3. Dimensions: 6 inches by 3/8 inch thick; non-tapered. B. Self-Expanding Butyl Strip Waterstops: Manufactured rectangular or trapezoidal strip, butyl rubber with sodium bentonite or other hydrophilic polymers, for adhesive bonding to concrete, 3/4 by 1 inch. 1. Manufacturers: Subject to compliance with requirements, available manufacturers offering products that may be incorporated into the Work include, but are not limited to the following: a. Henry Company, Sealants Division. 2.7 VAPOR RETARDERS A. Sheet Vapor Retarder: ASTM E 1745, Class A, not less than 10 mils thick. Include manufacturer's recommended adhesive or pressure-sensitive tape. 1. Manufacturers: Subject to compliance with requirements, available manufacturers offering products that may be incorporated into the Work include, but are not limited to THE KENT 03 35 00 - THE KENT Issue Date 05.09.18 CAST IN PLACE CONCRETE THE KENT the following: a. Raven Industries, Inc. b. Reef Industries, Inc. c. Stego Industries, LLC. 2.8 CURING MATERIALS A. Evaporation Retarder: Waterborne, monomolecular film forming, manufactured for application to fresh concrete. 1. Manufacturers: Subject to compliance with requirements, available manufacturers offering products that may be incorporated into the Work include, but are not limited to the following: a. BASF Corporation; Construction Systems. b. Dayton Superior. c. Euclid Chemical Company (The); an RPM company. d. Kaufman Products, Inc. B. Absorptive Cover: AASHTO M 182, Class 2, burlap cloth made from jute or kenaf, weighing approximately 9 oz. /sq. yd. when dry. C. Moisture-Retaining Cover: ASTM C 171, polyethylene film or white burlap-polyethylene sheet. D. Water: Potable. E. Clear, Waterborne, Membrane-Forming Curing Compound: ASTM C 309, Type 1, Class B, 18 to 25 percent solids, non-dissipating, certified by curing compound manufacturer to not interfere with bonding of floor covering. 1. Manufacturers: Subject to compliance with requirements, available manufacturers offering products that may be incorporated into the Work include, but are not limited to the following: a. BASF Corporation; Construction Systems. b. ChemMasters, Inc. c. Dayton Superior. d. Euclid Chemical Company (The); an RPM company. e. L&M Construction Chemicals, Inc. f. W. R. Meadows, Inc. 2.9 RELATED MATERIALS A. Expansion- and Isolation-Joint-Filler Strips: ASTM D 1751, asphalt-saturated cellulosic fiber. B. Bonding Agent: ASTM C 1059, Type II, non-redispersible, acrylic emulsion or styrene butadiene. 2.10 REPAIR MATERIALS A. Repair Underlayment: Cement-based, polymer-modified, self-leveling product that can be applied in thicknesses from 1/8 inch and that can be feathered at edges to match adjacent floor elevations. 1. Cement Binder: ASTM C 150, portland cement or hydraulic or blended hydraulic cement as defined in ASTM C 219. THE KENT 03 35 00 - THE KENT Issue Date 05.09.18 CAST IN PLACE CONCRETE THE KENT 2. Primer: Product of underlayment manufacturer recommended for substrate, conditions, and application. 3. Aggregate: Well-graded, washed gravel, 1/8 to 1/4 inch or coarse sand as recommended by underlayment manufacturer. 4. Compressive Strength: Not less than 4100 psi at 28 days when tested according to ASTM C 109. B. Repair Overlayment: Cement-based, polymer-modified, self-leveling product that can be applied in thicknesses from 1/4 inch and that can be filled in over a scarified surface to match adjacent floor elevations. 1. Cement Binder: ASTM C 150, portland cement or hydraulic or blended hydraulic cement as defined in ASTM C 219. 2. Primer: Product of topping manufacturer recommended for substrate, conditions, and application. 3. Aggregate: Well-graded, washed gravel, 1/8 to 1/4 inch or coarse sand as recommended by topping manufacturer. 4. Compressive Strength: Not less than 5000 psi at 28 days when tested according to ASTM C 109. 2.11 CONCRETE MIXTURES, GENERAL A. Prepare design mixtures for each type and strength of concrete, proportioned on the basis of laboratory trial mixture or field test data, or both, according to ACI 301. 1. Use a qualified independent testing agency for preparing and reporting proposed mixture designs based on laboratory trial mixtures. B. Cementitious Materials: Limit percentage, by weight, of cementitious materials other than portland cement in concrete as follows: 1. Fly Ash: 55 percent. C. Limit water-soluble, chloride-ion content in hardened concrete to 0.15 percent by weight of cement. D. Admixtures: Use admixtures according to manufacturer's written instructions. 1. Use water-reducing, high-range water-reducing or plasticizing admixture in concrete, as required, for placement and workability. 2. Use water-reducing and -retarding admixture when required by high temperatures, low humidity, or other adverse placement conditions. 3. Use water-reducing admixture in pumped concrete, and concrete with a w/c ratio below 0.50. 2.12 CONCRETE MIXTURES FOR BUILDING ELEMENTS A. Footings: Normal-weight concrete. 1. Minimum Compressive Strength: 3000 psi at 28 days. 2. Maximum W/C Ratio: .56. 3. Slump Limit: 4 inches, plus or minus 1 inch. 4. Provide Xypex C-500 admixture in Elevator pit footing concrete. B. Foundation Walls, Piers and Elements Exposed to Freezing & Thawing: Normal-weight concrete. 1. Minimum Compressive Strength: 4000 psi at 28 days. THE KENT 03 35 00 - THE KENT Issue Date 05.09.18 CAST IN PLACE CONCRETE THE KENT 2. Maximum W/C Ratio: 0.45. 3. Slump Limit: 4 inches, plus or minus 1 inch. 4. Air Content: 6 percent, plus or minus 1.5 percent at point of delivery for 1-inch nominal maximum aggregate size. 5. Provide Xypex C-500 admixture in Elevator pit foundation wall concrete. C. Interior Slabs-on-Grade: Normal-weight concrete. 1. Minimum Compressive Strength: 4000 psi at 28 days. 2. Maximum W/C Ratio: 0.45. 3. Minimum Cementitious Materials Content: 564 lb./cu. yd. 4. Slump Limit: 4 inches, plus or minus 1 inch. 5. Air Content: Do not allow air content of trowel-finished floors to exceed 3 percent. 2.13 FABRICATING REINFORCEMENT A. Fabricate steel reinforcement according to CRSI's "Manual of Standard Practice." 2.14 CONCRETE MIXING A. Ready-Mixed Concrete: Measure, batch, mix, and deliver concrete according to ASTM C 94, and furnish batch ticket information. 1. When air temperature is between 85 and 90 deg F, reduce mixing and delivery time from 1-1/2 hours to 75 minutes; when air temperature is above 90 deg F, reduce mixing and delivery time to 60 minutes. PART 3 - EXECUTION 3.1 FORMWORK INSTALLATION A. Design, erect, shore, brace, and maintain formwork, according to ACI 301, to support vertical, lateral, static, and dynamic loads, and construction loads that might be applied, until structure can support such loads. B. Construct formwork so concrete members and structures are of size, shape, alignment, elevation, and position indicated, within tolerance limits of ACI 117. C. Limit concrete surface irregularities, designated by ACI 347 as abrupt or gradual, as follows: 1. Class A, 1/8 inch for smooth-formed finished surfaces. 2. Class D, 1 inch for rough-formed finished surfaces. D. Construct forms tight enough to prevent loss of concrete mortar. E. Construct forms for easy removal without hammering or prying against concrete surfaces. Provide crush or wrecking plates where stripping may damage cast-concrete surfaces. Provide top forms for inclined surfaces steeper than 1.5 horizontal to 1 vertical. 1. Install keyways, reglets, recesses, and the like, for easy removal. 2. Do not use rust-stained steel form-facing material. F. Set edge forms, bulkheads, and intermediate screed strips for slabs to achieve required elevations and slopes in finished concrete surfaces. Provide and secure units to support screed THE KENT 03 35 00 - THE KENT Issue Date 05.09.18 CAST IN PLACE CONCRETE THE KENT strips; use strike-off templates or compacting-type screeds. G. Provide temporary openings for cleanouts and inspection ports where interior area of formwork is inaccessible. Close openings with panels tightly fitted to forms and securely braced to prevent loss of concrete mortar. Locate temporary openings in forms at inconspicuous locations. H. Chamfer exterior corners and edges of permanently exposed concrete. I. Form openings, chases, offsets, sinkages, keyways, reglets, blocking, screeds, and bulkheads required in the Work. Determine sizes and locations from trades providing such items. J. Clean forms and adjacent surfaces to receive concrete. Remove chips, wood, sawdust, dirt, and other debris just before placing concrete. K. Retighten forms and bracing before placing concrete, as required, to prevent mortar leaks and maintain proper alignment. L. Coat contact surfaces of forms with form-release agent, according to manufacturer's written instructions, before placing reinforcement. 3.2 EMBEDDED ITEM INSTALLATION A. Place and secure anchorage devices and other embedded items required for adjoining work that is attached to or supported by cast-in-place concrete. Use setting drawings, templates, diagrams, instructions, and directions furnished with items to be embedded. 1. Install anchor rods, accurately located, to elevations required and complying with tolerances in Section 7.5 of AISC 303. 3.3 REMOVING AND REUSING FORMS A. General: Formwork for sides of beams, walls, columns, and similar parts of the Work that does not support weight of concrete may be removed after cumulatively curing at not less than 50 deg F for 24 hours after placing concrete. Concrete must be hard enough to not be damaged by form-removal operations, and curing and protection operations need to be maintained. 1. Remove forms only if shores have been arranged to permit removal of forms without loosening or disturbing shores. B. Clean and repair surfaces of forms to be reused in the Work. Split, frayed, delaminated, or otherwise damaged form-facing material are not acceptable for exposed surfaces. Apply new form-release agent. C. When forms are reused, clean surfaces, remove fins and laitance, and tighten to close joints. Align and secure joints to avoid offsets. Do not use patched forms for exposed concrete surfaces unless approved by Architect. 3.4 VAPOR-RETARDER INSTALLATION A. Sheet Vapor Retarders: Place, protect, and repair sheet vapor retarder according to ASTM E 1643 and manufacturer's written instructions. 1. Lap joints 6 inches and seal with manufacturer's recommended tape. THE KENT 03 35 00 - THE KENT Issue Date 05.09.18 CAST IN PLACE CONCRETE THE KENT 3.5 STEEL REINFORCEMENT INSTALLATION A. General: Comply with CRSI's "Manual of Standard Practice" for fabricating, placing, and supporting reinforcement. 1. Do not cut or puncture vapor retarder. Repair damage and reseal vapor retarder before placing concrete. B. Clean reinforcement of loose rust and mill scale, earth, ice, and other foreign materials that reduce bond to concrete. C. Accurately position, support, and secure reinforcement against displacement. Locate and support reinforcement with bar supports to maintain minimum concrete cover. Do not tack weld crossing reinforcing bars. D. Set wire ties with ends directed into concrete, not toward exposed concrete surfaces. E. Install welded-wire reinforcement in longest practicable lengths on bar supports spaced to minimize sagging. Lap edges and ends of adjoining sheets at least one mesh spacing. Offset laps of adjoining sheet widths to prevent continuous laps in either direction. Lace overlaps with wire. 3.6 JOINTS A. General: Construct joints true to line with faces perpendicular to surface plane of concrete. B. Construction Joints: Install so strength and appearance of concrete are not impaired, at locations indicated or as approved by Architect. 1. Place joints perpendicular to main reinforcement. Continue reinforcement across construction joints unless otherwise indicated. Do not continue reinforcement through sides of strip placements of floors and slabs. 2. Form keyed joints as indicated. Embed keys at least 1-1/2 inches into concrete. 3. Locate horizontal joints in walls and columns at underside of floors, slabs, beams, and girders and at the top of footings or floor slabs. 4. Space vertical joints in walls as indicated. Locate joints beside piers integral with walls, near corners, and in concealed locations where possible. 5. Use a bonding agent at locations where fresh concrete is placed against hardened or partially hardened concrete surfaces. C. Contraction Joints in Slabs-on-Grade: Form weakened-plane contraction joints, sectioning concrete into areas as indicated. Construct contraction joints for a depth equal to at least one- fourth of concrete thickness as follows: 1. Sawed Joints: Form contraction joints with power saws equipped with shatterproof abrasive or diamond-rimmed blades. Cut 1/8-inch- wide joints into concrete when cutting action does not tear, abrade, or otherwise damage surface and before concrete develops random contraction cracks. D. Isolation Joints in Slabs-on-Grade: After removing formwork, install joint-filler strips at slab junctions with vertical surfaces, such as column pedestals, foundation walls, grade beams, and other locations, as indicated. 1. Extend joint-filler strips full width and depth of joint, terminating flush with finished THE KENT 03 35 00 - THE KENT Issue Date 05.09.18 CAST IN PLACE CONCRETE THE KENT concrete surface unless otherwise indicated. 3.7 WATERSTOP INSTALLATION A. Flexible Waterstops: Install in construction joints and at other joints indicated to form a continuous diaphragm. Install in longest lengths practicable. Support and protect exposed waterstops during progress of the Work. Field fabricate joints in waterstops according to manufacturer's written instructions. B. Self-Expanding Strip Waterstops: Install in construction joints and at other locations indicated, according to manufacturer's written instructions, adhesive bonding, mechanically fastening, and firmly pressing into place. Install in longest lengths practicable. 3.8 CONCRETE PLACEMENT A. Before placing concrete, verify that installation of formwork, reinforcement, and embedded items is complete and that required inspections are completed. B. Before test sampling and placing concrete, water may be added at Project site, subject to limitations of ACI 301. 1. Do not add water to concrete after adding high-range water-reducing admixtures to mixture. C. Deposit concrete continuously in one layer or in horizontal layers of such thickness that no new concrete is placed on concrete that has hardened enough to cause seams or planes of weakness. If a section cannot be placed continuously, provide construction joints as indicated. Deposit concrete to avoid segregation. 1. Deposit concrete in horizontal layers of depth not to exceed formwork design pressures and in a manner to avoid inclined construction joints. 2. Consolidate placed concrete with mechanical vibrating equipment according to ACI 301. 3. Do not use vibrators to transport concrete inside forms. Insert and withdraw vibrators vertically at uniformly spaced locations to rapidly penetrate placed layer and at least 6 inches into preceding layer. Do not insert vibrators into lower layers of concrete that have begun to lose plasticity. At each insertion, limit duration of vibration to time necessary to consolidate concrete and complete embedment of reinforcement and other embedded items without causing mixture constituents to segregate. D. Deposit and consolidate concrete for floors and slabs in a continuous operation, within limits of construction joints, until placement of a panel or section is complete. 1. Consolidate concrete during placement operations, so concrete is thoroughly worked around reinforcement and other embedded items and into corners. 2. Maintain reinforcement in position on chairs during concrete placement. 3. Screed slab surfaces with a straightedge and strike off to correct elevations. 4. Slope surfaces uniformly to drains where required. 5. Begin initial floating using bull floats or darbies to form a uniform and open-textured surface plane, before excess bleed-water appears on the surface. Do not further disturb slab surfaces before starting finishing operations. 3.9 FINISHING FORMED SURFACES A. Rough-Formed Finish: As-cast concrete texture imparted by form-facing material with tie holes THE KENT 03 35 00 - THE KENT Issue Date 05.09.18 CAST IN PLACE CONCRETE THE KENT and defects repaired and patched. Remove fins and other projections that exceed specified limits on formed-surface irregularities. 1. Apply to concrete surfaces not exposed to public view. B. Smooth-Formed Finish: As-cast concrete texture imparted by form-facing material, arranged in an orderly and symmetrical manner with a minimum of seams. Repair and patch tie holes and defects. Remove fins and other projections that exceed specified limits on formed-surface irregularities. 1. Apply to concrete surfaces exposed to public view, or to be covered with a coating or covering material applied directly to concrete. C. Related Unformed Surfaces: At tops of walls, horizontal offsets, and similar unformed surfaces adjacent to formed surfaces, strike off smooth and finish with a texture matching adjacent formed surfaces. Continue final surface treatment of formed surfaces uniformly across adjacent unformed surfaces unless otherwise indicated. 3.10 FINISHING FLOORS AND SLABS A. General: Comply with ACI 302.1R recommendations for screeding, straightening, and finishing operations for concrete surfaces. Do not wet concrete surfaces. B. Float Finish: Consolidate surface with power-driven floats or by hand floating if area is small or inaccessible to power-driven floats. Restraighten, cut down high spots, and fill low spots. Repeat float passes and straightening until surface is left with a uniform, smooth, granular texture. 1. Apply float finish to surfaces to receive trowel finish and to be covered with fluid-applied or sheet waterproofing, built-up or membrane roofing, or sand-bed terrazzo. C. Trowel Finish: After applying float finish, apply first troweling and consolidate concrete by hand or power-driven trowel. Continue troweling passes and restraighten until surface is free of trowel marks and uniform in texture and appearance. Grind smooth any surface defects that would telegraph through applied coatings or floor coverings. 1. Apply a trowel finish to surfaces exposed to view or to be covered with resilient flooring, carpet, ceramic or quarry tile set over a cleavage membrane, paint, or another thin-film- finish coating system. 2. Finish surfaces to the following tolerances, according to ASTM E 1155, for a randomly trafficked floor surface: a. Specified overall values of flatness, F(F) 45; and of levelness, F(L) 35; with minimum local values of flatness, F(F) 30; and of levelness, F(L) 24. D. Trowel and Fine-Broom Finish: Apply a first trowel finish to surfaces where ceramic or quarry tile is to be installed by either thickset or thinset method. While concrete is still plastic, slightly scarify surface with a fine broom. 1. Comply with flatness and levelness tolerances for trowel-finished floor surfaces. E. Broom Finish: Apply a broom finish to exterior concrete platforms, steps, ramps, and elsewhere as indicated. 1. Immediately after float finishing, slightly roughen trafficked surface by brooming with fiber-bristle broom perpendicular to main traffic route. Coordinate required final finish with Architect before application. THE KENT 03 35 00 - THE KENT Issue Date 05.09.18 CAST IN PLACE CONCRETE THE KENT 3.11 MISCELLANEOUS CONCRETE ITEM INSTALLATION A. Filling In: Fill in holes and openings left in concrete structures after work of other trades is in place unless otherwise indicated. Mix, place, and cure concrete, as specified, to blend with in- place construction. Provide other miscellaneous concrete filling indicated or required to complete the Work. B. Curbs: Provide monolithic finish to interior curbs by stripping forms while concrete is still green and by steel-troweling surfaces to a hard, dense finish with corners, intersections, and terminations slightly rounded. C. Equipment Bases and Foundations: 1. Coordinate sizes and locations of concrete bases with actual equipment provided. 2. Minimum Compressive Strength: 4000 psi at 28 days. 3. Install dowel rods to connect concrete base to concrete floor. Unless otherwise indicated, install dowel rods on 18-inch centers around the full perimeter of concrete base. 4. For supported equipment, install epoxy-coated anchor bolts that extend through concrete base and anchor into structural concrete substrate. 5. Prior to pouring concrete, place and secure anchorage devices. Use setting drawings, templates, diagrams, instructions, and directions furnished with items to be embedded. 6. Cast anchor-bolt insert into bases. Install anchor bolts to elevations required for proper attachment to supported equipment. D. Steel Pan Stairs: Provide concrete fill for steel pan stair treads, landings, and associated items. Cast-in inserts and accessories as shown on Drawings. Screed, tamp, and trowel finish concrete surfaces. 3.12 CONCRETE PROTECTING AND CURING A. General: Protect freshly placed concrete from premature drying and excessive cold or hot temperatures. Comply with ACI 306.1 for cold-weather protection and ACI 301 for hot-weather protection during curing. B. Evaporation Retarder: Apply evaporation retarder to unformed concrete surfaces if hot, dry, or windy conditions cause moisture loss approaching 0.2 lb/sq. ft. x h before and during finishing operations. Apply according to manufacturer's written instructions after placing, screeding, and bull floating or darbying concrete, but before float finishing. C. Formed Surfaces: Cure formed concrete surfaces, including underside of beams, supported slabs, and other similar surfaces. If forms remain during curing period, moist cure after loosening forms. If removing forms before end of curing period, continue curing for remainder of curing period. D. Unformed Surfaces: Begin curing immediately after finishing concrete. Cure unformed surfaces, including floors and slabs, concrete floor toppings, and other surfaces. E. Cure concrete according to ACI 308.1, by the following methods: 1. Curing Compound: Apply uniformly in continuous operation by power spray or roller according to manufacturer's written instructions. Recoat areas subjected to heavy rainfall within three hours after initial application. Maintain continuity of coating and repair damage during curing period. a. Removal: After curing period has elapsed, remove curing compound without THE KENT 03 35 00 - THE KENT Issue Date 05.09.18 CAST IN PLACE CONCRETE THE KENT damaging concrete surfaces by method recommended by curing compound manufacturer unless manufacturer certifies curing compound does not interfere with bonding of floor covering used on Project. 2. Curing and Sealing Compound: Apply uniformly to floors and slabs indicated in a continuous operation by power spray or roller according to manufacturer's written instructions. Recoat areas subjected to heavy rainfall within three hours after initial application. Repeat process 24 hours later and apply a second coat. Maintain continuity of coating and repair damage during curing period. a. Provide for all elements permanently exposed to view. 3.13 CONCRETE SURFACE REPAIRS A. Defective Concrete: Repair and patch defective areas when approved by Architect. Remove and replace concrete that cannot be repaired and patched to Architect's approval. B. Patching Mortar: Mix dry-pack patching mortar, consisting of 1 part portland cement to 2-1/2 parts fine aggregate passing a No. 16 sieve, using only enough water for handling and placing. C. Repairing Formed Surfaces: Surface defects include color and texture irregularities, cracks, spalls, air bubbles, honeycombs, rock pockets, fins and other projections on the surface, and stains and other discolorations that cannot be removed by cleaning. 1. Immediately after form removal, cut out honeycombs, rock pockets, and voids more than 1/2 inch in any dimension to solid concrete. Limit cut depth to 3/4 inch. Make edges of cuts perpendicular to concrete surface. Clean, dampen with water, and brush-coat holes and voids with bonding agent. Fill and compact with patching mortar before bonding agent has dried. Fill form-tie voids with patching mortar or cone plugs secured in place with bonding agent. 2. Repair defects on surfaces exposed to view by blending white portland cement and standard portland cement so that, when dry, patching mortar matches surrounding color. Patch a test area at inconspicuous locations to verify mixture and color match before proceeding with patching. Compact mortar in place and strike off slightly higher than surrounding surface. 3. Repair defects on concealed formed surfaces that affect concrete's durability and structural performance as determined by Architect. D. Repairing Unformed Surfaces: Test unformed surfaces, such as floors and slabs, for finish and verify surface tolerances specified for each surface. Correct low and high areas. Test surfaces sloped to drain for trueness of slope and smoothness; use a sloped template. 1. Repair finished surfaces containing defects. Surface defects include spalls, popouts, honeycombs, rock pockets, crazing and cracks more than 0.01-inch-wide or that penetrate to reinforcement or completely through unreinforced sections regardless of width, and other objectionable conditions. 2. After concrete has cured at least 14 days, correct high areas by grinding. 3. Correct localized low areas during or immediately after completing surface finishing operations by cutting out low areas and replacing with patching mortar. Finish repaired areas to blend into adjacent concrete. 4. Correct other low areas scheduled to receive floor coverings with a repair underlayment. Prepare, mix, and apply repair underlayment and primer according to manufacturer's written instructions to produce a smooth, uniform, plane, and level surface. Feather edges to match adjacent floor elevations. a. Correct other low areas scheduled to remain exposed with a repair topping. Cut out low areas to ensure a minimum repair topping depth of 1/4 inch to match adjacent floor elevations. Prepare, mix, and apply repair topping and primer according to manufacturer's written instructions to produce a smooth, THE KENT 03 35 00 - THE KENT Issue Date 05.09.18 CAST IN PLACE CONCRETE THE KENT uniform, plane, and level surface. 5. Repair defective areas, except random cracks and single holes 1 inch or less in diameter, by cutting out and replacing with fresh concrete. Remove defective areas with clean, square cuts and expose steel reinforcement with at least a 3/4-inch clearance all around. Dampen concrete surfaces in contact with patching concrete and apply bonding agent. Mix patching concrete of same materials and mixture as original concrete, except without coarse aggregate. Place, compact, and finish to blend with adjacent finished concrete. Cure in same manner as adjacent concrete. 6. Repair random cracks and single holes 1 inch or less in diameter with patching mortar. Groove top of cracks and cut out holes to sound concrete and clean off dust, dirt, and loose particles. Dampen cleaned concrete surfaces and apply bonding agent. Place patching mortar before bonding agent has dried. Compact patching mortar and finish to match adjacent concrete. Keep patched area continuously moist for at least 72 hours. E. Perform structural repairs of concrete, subject to Architect's approval, using epoxy adhesive and patching mortar. F. Repair materials and installation not specified above may be used, subject to Architect's approval. 3.14 FIELD QUALITY CONTROL A. Testing Agency: Engage a qualified testing and inspecting agency to perform tests and inspections and to submit reports. B. Inspections: 1. Steel reinforcement placement. 2. Headed bolts and studs. 3. Verification of use of required design mixture. 4. Concrete placement, including conveying and depositing. 5. Curing procedures and maintenance of curing temperature. C. Concrete Tests: Testing of composite samples of fresh concrete obtained according to ASTM C 172 shall be performed according to the following requirements: 1. Testing Frequency: Obtain one composite sample for each day's pour of each concrete mixture exceeding 5 cu. yd., but less than 25 cu. yd., plus one set for each additional 50 cu. yd. or fraction thereof. a. When frequency of testing provides fewer than five compressive-strength tests for each concrete mixture, testing shall be conducted from at least five randomly selected batches or from each batch if fewer than five are used. 2. Slump: ASTM C 143; one test at point of placement for each composite sample, but not less than one test for each day's pour of each concrete mixture. Perform additional tests when concrete consistency appears to change. 3. Air Content: ASTM C 231, pressure method, for normal-weight concrete; one test for each composite sample, but not less than one test for each day's pour of each concrete mixture. 4. Concrete Temperature: ASTM C 1064; one test hourly when air temperature is 40 deg F and below or 80 deg F and above, and one test for each composite sample. 5. Compression Test Specimens: ASTM C 31. a. Cast and laboratory cure two sets of two standard cylinder specimens for each composite sample. 6. Compressive-Strength Tests: ASTM C 39; test one set of two laboratory-cured specimens at 7 days and one set of two specimens at 28 days. a. A compressive-strength test shall be the average compressive strength from a set THE KENT 03 35 00 - THE KENT Issue Date 05.09.18 CAST IN PLACE CONCRETE THE KENT of two specimens obtained from same composite sample and tested at age indicated. 7. Strength of each concrete mixture will be satisfactory if every average of any three- consecutive compressive-strength tests equals or exceeds specified compressive strength and no compressive-strength test value falls below specified compressive strength by more than 500 psi. 8. Test results shall be reported in writing to Architect, concrete manufacturer, and Contractor within 48 hours of testing. Reports of compressive-strength tests shall contain Project identification name and number, date of concrete placement, name of concrete testing and inspecting agency, location of concrete batch in Work, design compressive strength at 28 days, concrete mixture proportions and materials, compressive breaking strength, and type of break for both 7- and 28-day tests. 9. Nondestructive Testing: Impact hammer, sonoscope, or other nondestructive device may be permitted by Architect but will not be used as sole basis for approval or rejection of concrete. 10. Additional Tests: Testing and inspecting agency shall make additional tests of concrete when test results indicate that slump, air entrainment, compressive strengths, or other requirements have not been met, as directed by Architect. Testing and inspecting agency may conduct tests to determine adequacy of concrete by cored cylinders complying with ASTM C 42 or by other methods as directed by Architect. 11. Additional testing and inspecting, at Contractor's expense, will be performed to determine compliance of replaced or additional work with specified requirements. 12. Correct deficiencies in the Work that test reports and inspections indicate do not comply with the Contract Documents. D. Measure floor and slab flatness and levelness according to ASTM E 1155 within 24 hours of finishing. END OF SECTION 03 30 00