Section 03360
CONCRETE CURING, FINISHING AND DAMPPROOFING
PART 1 - GENERAL
1.1 SUMMARY
A. Section Includes:
1. Mixing, placing, jointing, and curing of concrete construction.
B. Related Specification Sections include but are not necessarily limited to:
1. Division 01, Additional General Requirements
2. Section 03100, Concrete Formwork
3. Section 03200, Reinforcement Steel
4. Section 03300, Cast In-Place Concrete
5. Section 07900, Joint Sealants
1.2 QUALITY ASSURANCE
A. Referenced Standards:
1. American Concrete Institute (ACI):
116R Cement and Concrete Terminology
304R Guide for Measuring, Mixing, Transporting and Placing Concrete
304.2R Placing Concrete by Pumping Methods
305R Hot Weather Concreting
306R Cold Weather Concreting
308 Standard Practice for Curing Concrete
309R Guide for Consolidation of Concrete
2. ASTM International (ASTM):
C94 Standard Specification for Ready-Mixed Concrete
C156 Standard Test Method for Water Loss (from a Mortar Specimen) Through Liquid Membrane-Forming Curing Compounds for Concrete
C171 Standard Specification for Sheet Materials for Curing Concrete
C309 Standard Specification for Liquid Membrane-Forming
Compounds for Curing Concrete
D994 Standard Specification for Preformed Expansion Joint Filler for
Concrete (Bituminous Type)
D1056 Standard Specification for Flexible Cellular Materials-Sponge or
Expanded Rubber
D1751 Standard Specification for Preformed Expansion Joint Filler for Concrete Paving and Structural Construction (Nonextruding and Resilient Bituminous Types)
3. Corps of Engineers (COE):
CRD-C572 Specifications for Polyvinylchloride Waterstops
4. National Ready Mixed Concrete Association (NRMCA):
Checklist for Certification of Ready Mixed Concrete Production Facilities
5. National Sanitation Foundation International (NSF) B. Qualifications:
1. Ready Mixed Concrete Batch Plant: Certified by NRMCA
1.3 DEFINITIONS
A. Words and terms used in this Specification Section are defined in ACI 116R.
1.4 SUBMITTALS
A. Shop Drawings:
1. Submittals shall be made in accordance with the General Requirements, Additional General Requirements and as specified herein.
2. Product technical data including:
a. Acknowledgement that products submitted meet requirements of standards referenced.
b. Manufacturer's installation instructions.
1) Procedure for adding high-range water reducer at the jobsite.
c. Scaled (minimum 1/8 inch per foot) drawings showing proposed locations of construction joints and joint keyway dimensions.
d. Manufacturers and types:
1) Joint fillers.
2) Curing agents.
3) Construction joint bonding adhesive.
4) Pressure relief valves.
5) Waterstops.
3. Certifications:
a. Ready mix concrete plant certification.
b. Waterstops: Products shipped meet or exceed the physical properties specified.
1.5 DELIVERY, STORAGE, AND HANDLING A. Delivery:
1. Concrete:
a. Prepare a delivery ticket for each load of ready mixed concrete.
b. Truck operator shall hand ticket to CONTRACTOR at the time of delivery. c. Ticket to show:
1) Mix identification.
2) Quantity delivered.
3) Amount of material in each batch.
4) Outdoor temperature in the shade.
5) Time at which cement was added
6) Time of delivery.
7) Time of discharge.
8) Amount of water that may be added at the site without exceeding the specified water-cement ratio.
9) Amount of water added at the site.
PART 2 - PRODUCTS
2.1 ACCEPTABLE MANUFACTURERS
A. Subject to compliance with the Contract Documents, the manufacturers listed in the applicable Articles below are acceptable.
2.2 COMPONENTS
A. Neoprene Expansion Joint Fillers:
1. Acceptable manufacturers:
a. Permaglaze. b. Rubatex.
c. Williams Products. d. Or Equal.
2. Materials:
a. Closed cell neoprene.
b. ASTM D1056, Class SC.
c. Compression deflection: As required to limit deflection to 50 percent of joint thickness under pressure from concrete pour height.
B. Asphalt Expansion Joint Fillers:
1. Acceptable manufacturers:
a. W R Meadows.
b. J and P Petroleum Products. c. Or Equal.
2. Materials: ASTM D994.
C. Fiber Expansion Joint Fillers:
1. Materials: ASTM D1751. D. Waterstops, PVC Type:
1. Acceptable manufacturers:
a. Greenstreak Plastic Products. b. W R Meadows.
c. Or Equal.
2. Materials:
a. Virgin polyvinyl chloride compound not containing any scrap or reclaimed materials or pigment.
b. Standard: COE CRD-C572.
3. In expansion joints:
a. 9 inches wide by 3/8 inch thick tear web type waterstop.
b. 2 inches minimum horizontal movement without rupturing.
c. Greenstreak Plastic Products Style #700, Durajoint PVC Waterstop, Or
Equal.
4. In control joints:
a. 6 inches wide by 3/8 inch thick with ribs and center bulb.
b. Greenstreak Plastic Products Style #705, Durajoint PVC Waterstop, Or
Equal.
5. In all other joints:
a. 6 inches wide by 3/8 inch thick with ribs and center bulb.
b. Greenstreak Plastic Products Style #705, #679 or #783, Durajoint PVC Waterstop, Or Equal.
6. Provide hog rings or grommets at maximum 12 inches OC along the length of the waterstop.
7. Provide factory-made waterstop fabrications at all changes in direction, intersections and transitions, leaving only straight butt splices for the field.
E. Waterstops, Preformed Strip Type:
1. Acceptable manufacturers:
a. Hydrotite CJ by Greenstreak Plastics, Inc. b. Adeka Ultra Seal USA.
c. Or Equal.
2. Materials:
a. Hydrophilic type waterstop manufactured solely for the purpose of preventing water from traveling through construction joints.
b. Hydrotite type CJ-0725-3K.
F. Sand Cement Grout, Non-Shrink Grout and Epoxy Grout: See Specification Section
03600, Grouts.
PART 3 - EXECUTION
3.1 PREPARATION A. General:
1. Complete formwork.
a. See Specification Section 03100, Concrete Formwork.
2. Remove earth, snow, ice, water, and other foreign materials from areas that will receive concrete.
3. Secure reinforcement in place.
a. See Specification Section 03200, Reinforcement Steel.
4. Position expansion joint material, anchors and other embedded items.
5. Obtain acceptance of reinforcement erection and placement prior to placing concrete.
6. Do not place concrete during rain, sleet, or snow, unless adequate protection is provided and acceptance is obtained.
a. Plan size of crews with due regard for effects of concrete temperature and atmospheric conditions on rate of hardening of concrete as required to obtain good surfaces and avoid unplanned cold joints.
b. Do not allow rainwater to increase mixing water nor to damage surface finish.
7. Prepare all construction joints for proper bond per Paragraph 3.4C. of this
Specification Section.
8. Remove hardened concrete and foreign materials from inner surfaces of conveying equipment and formwork.
9. Provide slabs and beams of minimum indicated required depth when sloping structural foundation base slabs and elevated slabs to drains.
a. For floor slabs on grade, slope top of subgrade to provide slab of required uniform thickness.
B. Preparation of Subgrade for Slabs On Ground:
1. Subgrade drained and of adequate and uniform load-bearing nature.
2. Obtain acceptance of subgrade compaction density prior to placing slabs on ground.
3. Maintain subgrade at a temperature above 32 degrees F before concrete placing begins for a sufficient amount of time to remove frost.
4. Moisten subgrade to eliminate absorption.
a. Keep subgrade moist at time of concreting.
b. Allow no free-standing water on subgrade or soft or muddy spots when concrete is placed.
C. Edge Forms and Screeds:
1. Set accurately to produce designated elevations and contours of finished surface.
2. Sufficiently strong to support vibrating screeds or roller pipe screeds, if required.
3. Use strike off templates, or approved vibrating type screeds, to align concrete surfaces to contours of screed strips.
3.2 CONCRETE MIXING
A. General:
1. Provide all concrete from a central plant conforming to Checklist for Certification of Ready Mixed Concrete Production Facilities of the NRMCA.
2. Batch, mix, and transport in accordance with ASTM C94. B. Control of Admixtures:
1. Charge admixtures into mixer as solutions.
a. Measure by means of an approved mechanical dispensing device. b. Liquid considered a part of mixing water.
c. Admixtures that cannot be added in solution may be weighed or measured by volume if so recommended by manufacturer.
2. Add separately, when two or more admixtures are used in concrete, to avoid possible interaction that might interfere with efficiency of either admixture, or adversely affect concrete.
3. Complete addition of retarding admixtures within one minute after addition of water to cement has been completed, or prior to beginning of last three quarters of required mixing, whichever occurs first.
C. Tempering and Control of Mixing Water:
1. Mix concrete only in quantities for immediate use.
2. Discard concrete which has set.
3. Discharge concrete from ready mix trucks within time limit and drum revolutions stated in ASTM C94.
4. Addition of water at the jobsite:
a. See Specification Section 03300, Cast-in-Place Concrete, for specified water cement ratio and slump.
b. Do not exceed maximum specified water cement ratio or slump.
c. Incorporate water by additional mixing equal to at least half of total mixing required.
d. Perform strength test on any concrete to which water has been added at the jobsite.
1) See Specification Section 03350, Concrete Testing.
3.3 PLACING OF CONCRETE
A. General:
1. Comply with ACI 304R and ACI 304.2R.
2. Deposit concrete:
a. Continuously to avoid cold joints. b. In layers of 12 to 18 inches.
3. Locate construction joints at locations accepted by ENGINEER.
a. Plan size of crews with due regard for effects of concrete temperature and atmosphere conditions to avoid unplanned cold joints.
4. Place concrete at such a rate that concrete, which is being integrated with fresh concrete, is still workable.
5. Do not deposit concrete which has partially hardened or has been contaminated by foreign materials.
6. Spreaders:
a. Temporary: Remove as soon as concrete placing renders their function unnecessary.
b. Embedded:
1) Obtain acceptance of ENGINEER.
2) Materials: Concrete or metal.
3) Ends of metal spreaders coated with plastic coating 2 inches from each end.
7. Do not begin placing of concrete in supported elements until concrete previously placed in supporting members is no longer plastic and has been in place at least a minimum of 2 hours.
8. Deposit concrete as nearly as practicable in its final position to avoid segregation.
a. Maximum free fall: 4 feet.
b. Free fall exceeding 4 feet: Place concrete by means of hopper, elephant trunk or tremie pipe extending down to within 4 feet of surface placed upon.
9. Perform the following operations before bleeding water has an opportunity to collect on surface:
a. Spread.
b. Consolidate. c. Straightedge.
d. Darby or bull float.
B. Admixtures:
1. All admixtures to be introduced at the batch plant in accordance with manufacturer's recommendations.
C. Cold Weather Concrete Placement:
1. Comply with ACI 306R.
2. Do not place concrete on substrates that are below 32 degrees F or contain frozen material.
3. Maintain all materials, forms, reinforcement, subgrade and any other items which concrete will come in contact with free of frost, ice or snow at time of concrete placement.
4. Temperature of concrete when discharged at site:
- Air TemperatureDegrees FMinimum ConcreteTemperature, Degrees F for Sections with Least Dimension Less than 12InchesMinimum ConcreteTemperature, Degrees F for Sections with Least Dimension12 Inches or Greater30 to 4560550 to 306555below 07060
5. Heat subgrade, forms, and reinforcement so the temperature of the subgrade, forms, and reinforcement will be between 45 and 70 degrees F, when temperature of surrounding air is 40 degrees F or below at time concrete is placed.
a. Remove all frost from subgrade, forms and reinforcement before concrete is placed.
6. Combine water with aggregate in mixer before cement is added, if water or aggregate is heated above 90 degrees F.
7. Do not mix cement with water or with mixtures of water and aggregate having a temperature greater than 90 degrees F.
8. Do not place slabs on ground if temperature is below 40 degrees F or if temperature surrounding the slab will be below 40 degrees F before structure is enclosed and heated.
D. Hot Weather Concrete Placement:
1. Comply with ACI 305R.
2. Cool ingredients before mixing, or add flake ice or well crushed ice of a size that will melt completely during mixing for all or part of mixing water if high temperature, low slump, flash set, cold joints, or shrinkage cracks are encountered.
3. Temperature of concrete when placed:
a. Not to exceed 90 degrees F. b. Not so high as to cause:
1) Shrinkage cracks.
2) Difficulty in placement due to loss of slump.
3) Flash set.
4. Temperature of forms and reinforcing when placing concrete:
a. Not to exceed 90 degrees F.
b. May be reduced by spraying with water to cool below 90 degrees F.
1) Leave no standing water to contact concrete being placed. E. Consolidating:
1. Consolidate in accordance with ACI 309R except as modified herein.
2. Consolidate by vibration so that concrete is thoroughly worked around reinforcement, embedded items and into corners of forms.
a. Eliminate:
1) Air or stone pockets.
2) Honeycombing or pitting.
3) Planes of weakness.
3. Internal vibrators:
a. Minimum frequency of 8000 vibrations per minute.
b. Insert and withdraw at points approximately 18 inches apart.
1) Allow sufficient duration at each insertion to consolidate concrete but not sufficient to cause segregation.
c. Use in:
1) Beams and girders of framed slabs.
2) Columns and walls.
d. Size of vibrators shall be in accordance with ACI 309R, Table 5.1.5.
4. Obtain consolidation of slabs with internal vibrators, vibrating screeds, roller pipe screeds, or other accepted means.
5. Do not use vibrators to transport concrete within forms.
6. Provide spare vibrators on jobsite during all concrete placing operations.
7. Bring a full surface of mortar against form by vibration supplemented if necessary by spading to work coarse aggregate back from formed surface, where concrete is to have an as-cast finish.
8. Use suitable form vibrators located just below top surface of concrete, where internal vibrators cannot be used in areas of congested reinforcing.
9. Prevent construction equipment, construction operations, and personnel from introducing vibrations into freshly placed concrete after the concrete has been placed and consolidated.
F. Handle concrete from mixer to place of final deposit by methods which will prevent segregation or loss of ingredients and in a manner which will assure that required quality of concrete is maintained.
1. Use truck mixers, agitators, and non-agitating units in accordance with ASTM C94.
2. Horizontal belt conveyors:
a. Mount at a slope which will not cause segregation or loss of ingredients. b. Protect concrete against undue drying or rise in temperature.
c. Use an arrangement at discharge end to prevent segregation. d. Do not allow mortar to adhere to return length of belt.
e. Discharge conveyor runs into equipment specially designed for spreading concrete.
3. Metal or metal lined chutes:
a. Slope not exceeding 1 vertical to 2 horizontal and not less than 1 vertical to 3 horizontal.
b. Chutes more than 20 feet long and chutes not meeting slope requirements may be used provided they discharge into a hopper before distribution.
c. Provide end of each chute with a device to prevent segregation.
4. Pumping or pneumatic conveying equipment:
a. Designed for concrete application and having adequate pumping capacity.
b. Control pneumatic placement so segregation is avoided in discharged concrete.
c. Loss of slump in pumping or pneumatic conveying equipment shall not exceed 1-1/2 inches.
d. Do not convey concrete through pipe made of aluminum or aluminum alloy. e. Provide pumping equipment without Y sections.
G. Placing of Concrete on Metal Deck:
1. Prior to concrete placement, the metal deck shall be free of soil, debris, standing water, loose mill scale, and all other foreign matter.
2. Care shall be exercised when placing concrete so that the deck will not be subject to construction loads or impact that exceed the design capacity of the deck.
3. Concrete shall be placed in a uniform manner and spread toward the center of the deck span.
4. If buggies are used to place concrete, runways shall be planked, and the buggies shall only operate on planking.
a. Planks shall be of adequate stiffness to transfer loads to the steel supports without damaging the deck.
5. Deck damage caused by careless placement of concrete shall be repaired or replaced.
3.4 JOINTS AND EMBEDDED ITEMS
A. Construction Joints - General:
1. Locate joints as indicated on the Drawings or as shown on accepted shop drawings.
a. Where construction joint spacing shown on Drawings exceeds the joint spacing indicated in Paragraph B below, submit proposed construction joint location in conformance with this Specification Section.
2. Unplanned construction joints will not be allowed.
a. If concrete cannot be completely placed between planned construction joints, then it must be removed.
3. In general, locate joints near middle of spans of slabs, beams and girders unless a beam intersects a girder at this point, in which case, offset joint in girder a distance equal to twice the width of the beam.
4. Locate joints in walls and columns at underside of floors, slabs, beams, or girders, and at tops of foundations or floor slabs, unless shown otherwise.
a. At CONTRACTOR's option, beam pockets may be formed into concrete walls.
b. Size pockets to allow beam reinforcing to be placed as detailed on Drawings.
5. Place beams, girders, column capitals and drop panels at same time as slabs.
6. Place corbels monolithically with walls.
a. Locate wall vertical construction joints midway between corbels.
b. Where only a single corbel is located place it also monolithically with wall and locate wall vertical construction joint a minimum of 3 feet from face of corbel.
7. Make joints perpendicular to main reinforcement with all reinforcement continuous across joints.
8. Provide roughened construction joints at all construction joints unless indicated otherwise on Drawings.
a. Clean the previously hardened concrete interface and remove all laitance. b. Intentionally roughen the interface to a full amplitude of 1/4 inch.
c. Provide recessed flat surface as required to install strip type waterstops.
9. Provide continuous keyways at all construction joints.
a. Construction joint keyways shall have the following dimensions, unless shown otherwise on Drawings or directed otherwise by ENGINEER.
b. Construction joint keyways in walls:
1) Keyway width, not less than 1/3 and not more than 1/2 the wall thickness measured perpendicular to wall faces.
2) Keyway depth to be not less than 1-1/2 inches.
3) Place keyway in wall center unless shown otherwise on Drawings.
c. Construction joint keyways in footings, foundations, base slabs, and structural or elevated slabs:
1) Keyway height not less than 1/3 and not more than 1/2 the footing or slab thickness.
2) Keyway depth not less than 1-1/2 inches.
3) Keyway in footing or slab center unless shown otherwise on Drawings. d. Construction joint keyways in beams:
1) Keyway height not less than 1/3 and not more than 1/2 the beam depth.
2) Keyway depth not less than 1-1/2 inches.
3) Keyway in beam center unless shown otherwise on Drawings.
10. Allow a minimum of 48 hours before placement of adjoining concrete construction.
B. Construction Joints - Spacing:
1. General - Structures not intended to contain liquid:
a. Wall vertical construction joints:
1) 60 feet maximum centers.
2) At wall intersections, 30 feet maximum from corner. b. Wall horizontal construction joints: 20 to 25 feet centers.
c. Base slab, floor, and roof slab construction joints:
1) Placements to be approximately square and not to exceed 3,500 square feet.
2) Maximum side dimension of a slab pour to be less than:
a) Twice the length of the short side. b) 80 feet.
2. Structures intended to contain liquids:
a. Wall vertical construction joints:
1) 30 feet maximum centers.
2) At wall intersections, 15 feet maximum from corner. b. Wall horizontal construction joints: 12 to 18 feet centers.
c. Walls that are thicker than 18 inches may be poured less than 30 feet tall in one (1) pour provided the following requirements are satisfied:
1) A test wall of similar size, height and thickness will be poured to demonstrate the quality of the concrete work.
2) The test wall will be located as a portion of a non-water bearing wall. a) The test wall will include a waterstop at the bottom of the wall.
b) Alternatively, a separate test wall, not part of the final work, may be constructed.
3) The concrete placement and concrete quality of the test wall will be observed by the ENGINEER.
a) Concrete will be judged on the following:
(1) Ability to keep bottom of the pour clean and free from trash and debris.
(2) Ability to protect the waterstop from folding over due to the force of falling concrete.
(3) Ability to properly consolidate all concrete in the wall pour, including below formed openings.
4) ENGINEER will evaluate the CONTRACTOR’s work and may recommend taller concrete wall pours if concrete quality is acceptable.
5) Preparation for all subsequent wall pours over 18 feet tall must be the same as the preparation of the test wall.
6) Should the quality of concrete work on subsequent wall pours be judged inadequate, the CONTRACTOR may be directed to limit wall pour heights to
18 feet as originally specified.
7) Should the quality of concrete work on the test wall be judged inadequate, additional test walls will not be observed and judged to allow pour heights greater that 18 feet unless allowed by ENGINEER.
d. Base slab, floor, and roof slab construction joints:
1) Placements to be approximately square and not to exceed 2,000 square feet.
2) Maximum side dimension of a slab pour to be less than:
a) Twice the length of the short side. b) 60 feet.
C. Construction Joints - Bonding:
1. Obtain bond between concrete pours at construction joints by thoroughly cleaning and removing all laitance from construction joints.
a. Before new concrete is placed, all construction joints shall be coated with cement grout, or dampened.
1) General: Use cement grout or dampening for all construction joints.
2. Roughened construction joints:
a. Roughen the surface of the concrete to expose the aggregate uniformly
b. Remove laitance, loosened particles of aggregate or damaged concrete at the surface, or at the CONTRACTOR's option, use an accepted chemical retarder which delays but does not prevent setting of the surface of the mortar in accordance with the manufacturer's recommendations.
1) Retarded mortar shall be removed within 24 hours after placing to produce a clean exposed aggregate bonding surface.
c. Cover the hardened concrete of horizontal joints with a coat of cement grout of similar proportions to the concrete, except substitute fine aggregate for coarse aggregate.
d. Place 1 inch layer of grout in bottoms of wall or column lifts immediately before placing concrete.
1) Vibrate grout and first layer of concrete simultaneously.
e. Place fresh concrete before the grout has attained its initial set.
3. Other keyed construction joints:
a. Thoroughly clean construction joints and remove all laitance.
b. Dampen the hardened concrete (but do not saturate) immediately prior to placing of fresh concrete.
D. Locate control joints in slabs on grade as indicated on Drawings.
1. Time cutting properly with set of concrete, if saw cut joints are required or permitted.
a. Start cutting as soon as concrete has hardened sufficiently to prevent aggregates being dislodged by saw.
b. Complete before shrinkage stresses become sufficient to produce cracking.
E. Expansion Joints:
1. Do not permit reinforcement or other embedded metal items bonded to concrete (except smooth dowels bonded on only one side of joint) to extend continuously through an expansion joint.
2. Use neoprene expansion joint fillers, unless noted otherwise on Drawings.
3. Seal expansion joints as shown on Drawings.
a. See Specification Section 07900, Joint Sealants, for requirements. F. Waterstops:
1. Preformed strip type:
a. Install on smooth surface of hardened concrete by use of nails, adhesive or other means as recommended by manufacturer to prevent movement of waterstop during placement of concrete.
b. Waterstop to be continuous with splices in accordance with manufacturer's instructions.
c. Use in joints against existing concrete and where indicated on Drawings.
2. PVC type:
a. Position waterstop accurately in forms.
b. Secure waterstops in correct position using hog rings or grommets spaced along the length of waterstop and tie wire to adjacent reinforcing.
c. Hold horizontal waterstops in place with continuous supports. d. Install according to manufacturer's instructions.
1) Do not displace reinforcement from required location. e. Waterstops to be continuous.
f. Splice ends with perpendicular butt splice using electrical splicing iron in accordance with manufacturer's instructions.
g. Unless otherwise noted, use for all construction joints in new construction for all structures indicated on Drawings.
G. Other Embedded Items:
1. Place sleeves, inserts, anchors, and embedded items required for adjoining work or for its support, prior to initiating concreting.
2. Do not place electrical conduit, drains, or pipes in or thru concrete slabs, walls, columns, foundations, beams or other structural members unless accepted by ENGINEER.
H. Placing Embedded Items:
1. Position expansion joint material, waterstops, and other embedded items accurately.
2. Support against displacement.
3. Fill voids in sleeves, inserts and anchor slots temporarily with readily removable material to prevent entry of concrete into voids.
4. Provide adequate means for anchoring waterstop in concrete.
a. Provide means to prevent waterstops in the forms from being folded over by the concrete as it is placed.
b. Work concrete under the waterstops by hand, so as to avoid the formation of air and rock pockets, when placing roof and floor slab concrete around waterstops.
3.5 FINISHING
A. See Specification Section 03360, Concrete Curing, Finishing and Dampproofing. B. Coordinate mixing and placing with finishing.
3.6 INSTALLATION OF GROUT A. Grout Schedule of Use:
1. Sand cement grout:
a. Fill keyways if precast HCU.
b. General use.
2. Non-shrinking non-metallic grout:
a. Filling form tie holes.
b. Under column and beam base plates.
c. Other uses indicated on the Drawings.
3. Epoxy grout:
a. Patching cavities in concrete.
b. Grouting of dowels and anchor bolts into existing concrete.
c. Grouting of equipment base plates where driving motor is 500 HP and above. d. Other uses indicated on the Drawings.
B. Grout Installation:
1. Sand cement grout:
a. Fill keyways between precast concrete hollow core slabs with sand cement grout.
b. Consolidate grout by rodding or by other means to assure complete filling of keyways.
c. Cure grout by one of methods specified.
2. Non-shrink non-metallic grout:
a. Clean concrete surface to receive grout.
b. Saturate concrete with water for 24 hours prior to grouting. c. Mix in a mechanical mixer.
d. Use no more water than necessary to produce flowable grout. e. Place in accordance with manufacturer's instructions.
f. Provide under beam, column, and equipment base plates, in joints between precast concrete filter slabs, and in other locations indicated on the Drawings.
g. Completely fill all spaces and cavities below the top of base plates.
h. Provide forms where base plates and bed plates do not confine grout. i. Where exposed to view, finish grout edges smooth.
j. Except where a slope is indicated on the Drawings, finish edges flush at the base plate, bed plate, member or piece of equipment.
k. Coat exposed edges of grout with cure or seal compound recommended by the grout manufacturer.
3. Epoxy grout:
a. Mix and place in accordance with manufacturer's instructions. b. Apply only to clean, dry, sound surface.
c. Completely fill all cavities and spaces around dowels and anchors without voids.
d. Grout base and bed plates as specified for non-shrinking, non-metallic grout. e. Obtain manufacturer's field technical assistance as required to assure proper
placement.
3.7 CURING AND PROTECTION
A. Protect concrete from premature drying, excessively hot or cold temperatures, and mechanical injury immediately after placement, and maintain with minimal moisture loss at relatively constant temperature for period necessary for hydration of cement, hardening, and compressive strength gain.
1. Follow recommendations of ACI 308 except as modified herein.
B. Apply one of the following curing procedures immediately after completion of placement and finishing, for concrete surfaces not in contact with forms.
1. Ponding or continuous sprinkling.
2. Application of absorptive mats or fabric kept continuously wet.
3. Application of sand kept continuously wet.
4. Continuous application of steam (not exceeding 150 degrees F) or mist spray.
5. Application of waterproof sheet materials, conforming to ASTM C171.
6. Application of other moisture retaining covering as accepted.
7. Application of a curing compound conforming to ASTM C309.
a. Apply curing compound in accordance with manufacturer's recommendations immediately after any water sheen which may develop after finishing has disappeared from concrete surface.
b. Do not use on any surface against which additional concrete or other material is to be bonded unless it is proven that curing compound will not prevent bond.
c. Where a vertical surface is cured with a curing compound, the vertical surface shall be covered with a minimum of two (2) coats of the curing compound.
1) Apply the first coat of curing compound to a vertical surface immediately after form removal.
2) The vertical concrete surface at the time of receiving the first coat shall be damp with no free water on the surface.
3) Allow the preceding coat to completely dry prior to applying the next coat.
4) A vertical surface: Any surface steeper than 1 vertical to 4 horizontal. C. Curing Concrete In Contact with Forms:
1. Minimize moisture loss from and temperature gain of concrete placed in forms exposed to heating by sun by keeping forms wet and cool until they can be safely removed.
2. After form removal, cure concrete until end of time prescribed. a. Use one of methods listed above.
3. Forms left in place shall not be used as a method of curing in hot weather.
4. The term "hot weather," where used in these Specifications, is defined in ACI
305R.
5. In hot weather, remove forms from vertical surfaces as soon as concrete has gained sufficient strength so that the formwork is no longer required to support the concrete.
D. Continue curing for at least seven (7) days for all concrete except high early strength concrete for which period shall be at least three (3) days.
1. If one of curing procedures indicated above is used initially, it may be replaced by one of other procedures indicated any time after concrete is one (1) day old, provided concrete is not permitted to become surface dry during transition.
E. Cold Weather:
1. Follow recommendations of ACI 306R.
2. Maintain temperature of concrete between 50 and 70 degrees F for required curing period, when outdoor temperature is 40 degrees F, or less.
3. Use heating, covering, insulating, or housing of the concrete work to maintain required temperature without injury due to concentration of heat.
4. Do not use combustion heaters unless precautions are taken to prevent exposure of concrete to exhaust gases which contain carbon dioxide.
5. Interior slabs in areas intended to be heated shall be adequately protected so that frost does not develop in the supporting subgrade.
F. Hot Weather:
1. Follow recommendations of ACI 305R.
2. Make provision for cooling forms, reinforcement and concrete, windbreaks, shading, fog spraying, sprinkling, ponding, or wet covering with a light colored material.
3. Provide protective measures as quickly as concrete hardening and finishing operations will allow.
G. Rate of Temperature Change:
1. Keep changes in temperature of air immediately adjacent to concrete as uniform as possible, during and immediately following curing period.
2. Do not exceed a temperature change of 5 degrees F in any 1 hour or 50 degrees
F in any 24-hour period.
H. Protection from Mechanical Injury:
1. Protect concrete from damaging mechanical disturbances, such as load stresses, heavy shock, and excessive vibration.
2. Protect finished concrete surfaces from damage by construction equipment, materials, or methods, and by rain or running water.
3. Do not load self supporting structures in such a way as to overstress concrete.
3.8 FIELD QUALITY CONTROL
A. Tests in accordance with Specification Section 03350, Testing.
1. Perform a strength test on all concrete to which water or superplasticizer, above the amount stated in the accepted concrete mix design, has been added.
a. Perform sampling after water or superplasticizer has been added and additional mixing has been performed.
B. Field samples of fabricated waterstop fittings (crosses, tees, etc.) will be selected at random by the ENGINEER for testing by a laboratory at the OCSD's expense.
1. When tested, they shall have a tensile strength across the joints equal to at least
600 pounds per inch.
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