HomeMy WebLinkAboutSection 03300 Cast-in-Place Concrete
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SECTION 03300 CAST-IN-PLACE CONCRETE
PART 1 - GENERAL
1.01 SCOPE:
A. The work of this Section consists of furnishing all labor, equipment, supplies, and
materials necessary for the proper placement, curing, finishing, protection, and repair
of the cast-in-place concrete required by the Contract Documents.
1. SECTION 02200 - Earthwork
1.02 APPLICABLE PUBLICATIONS: The following standard specifications shall apply to the
Work of this Section:
A. American Concrete Institute (ACI)
1. ACI 117 - Standard Tolerance for Concrete Construction and Materials.
2. ACI 301 - Structural Concrete for Buildings
3. ACI 304.2R - Recommended Practice for Measuring, Mixing, Transporting, and
Placing Concrete
4. ACI 305 - Committee Report on Hot-Weather Concreting
5. ACI 306 - Committee Report on Cold-Weather Concreting
6. ACI 308 - Standard Specification for Curing Concrete
7. ACI 309 - Consolidation of Concrete
8. ACI 318 - Building Code Requirements for Reinforced Concrete
B. American Society for Testing and Materials (ASTM):
1. C 31 - Making and Curing Concrete compression and Flexure Test Specimens
in the Field
2. C 33 - Concrete Aggregates
3. C 39 - Compressive Strength of Cylindrical Concrete Specimens
4. C 94 - Ready-Mixed Concrete
5. C 127 - Test Method for Specific Gravity and Absorption of Coarse Aggregate
6. C 128 - Test Method for Specific Gravity and Absorption of Fine Aggregate
7. C 136 - Method for Sieve Analysis of Fine and Coarse Aggregates
8. C 143 - Test Method for Slump of Hydraulic Cement Concrete
9. C 150 - Portland Cement
10. C 156 - Test Method for Water Retention by Concrete Curing Materials
11. C 157 - Test Method for Length Change of Hardened Hydraulic Cement Mortar
and Concrete
12. C 173 - Standard Test Method for Air Content of Freshly Mixed Concrete by the
Volumetric Method
13. C 231 - Standard Test Method for Air Content of Freshly Mixed Concrete by the
Pressure Method
14. C 260 - Specification for Air Entraining Admixtures for Concrete.
15. C 309 - Liquid Membrane-Forming Compounds for Curing Concrete
16. C 494 - Chemical Admixtures for Concrete
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17. C 566 - Test Method for Total Moisture Content of Aggregate by Drying
18. C 618 - Standard Specification for Coal Fly Ash and Raw or Calcined Natural
Pozzolan for Use as a Mineral Admixture in Concrete
19. C 881 - Standard Specification for Epoxy-Resin-Base Bonding Systems for
Concrete
20. C 1077 - Practice for Laboratories Testing Concrete and Concrete Aggregates
for use in Construction and Criteria for Laboratory Evaluation
21. C 1240 - Standard Specification for Silica Fume for Use as a Mineral Admixture
in Hydraulic-Cement Concrete, Mortar, and Grout
22. D 1751 - Standard Specification for Preformed Expansion Joint Filler for
Concrete Paving and Structural Construction (Nonextruding and Resilient
Bituminous Types)
23. D 2419 - Test Methods for Sand Equivalent Value of Soils and Fine Aggregate
24. E 96 - Water Vapor Transmission of Materials
25. E 1643 - Standard Practice for Installation of Water Vapor Retarders Used in
Contact with Earth or Granular Fill Under Concrete Slabs
C. Federal Specifications
1. UU-B-790A - Building Paper, Vegetable Fiber (Kraft, Waterproofed, Water
Repellant and Fire Resistant).
D. Florida Building Code and Local Building Codes as appropriate.
1.03 DEFINITIONS:
A. Structural Concrete: Concrete to be used in all cases except where indicated
otherwise in the Contract Documents.
B. Pea Gravel Concrete: Concrete in thin sections and areas with congested
reinforcing, at the option of the CONTRACTOR and with written approval of the
ENGINEER for the specific location.
C. Sitework Concrete: Concrete to be used for curbs, gutters, catch basins, sidewalks,
pavements, fence and guard post embedment, underground pipe encasement,
underground duct bank encasement and all other concrete appurtenant to electrical
facilities unless otherwise indicated.
D. Lean Concrete: Concrete to be used for thrust blocks, pipe trench cut-off blocks and
cradles that are indicated on the Drawings as un-reinforced. Lean concrete shall be
used as protective cover for dowels intended for future connection.
E. Hydraulic Structure: An environmental engineering concrete structures for the
containment, treatment, or transmission of water, wastewater, other fluids, or gases.
1.04 SUBMITTALS:
A. Mix Designs:
1. Prior to beginning the WORK and within 14 days of the Notice to Proceed, the
CONTRACTOR shall submit preliminary concrete mix designs which shall
show the proportions and gradations of all materials proposed for each class
and type of concrete. Mix designs shall be checked by an independent testing
laboratory acceptable to the ENGINEER. All costs related to such checking
shall be CONTRACTOR’S responsibility.
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2. Test data relating to the cement, aggregate, and admixtures shall be less than
six months old. Furnish the submittals in accordance with ACI 301 for the
following:
a. Mill tests for cement.
b. Admixture certification. Chloride ion content shall be included.
c. Aggregate gradation test results and certification.
d. Delivery Tickets:
3. Where ready-mix concrete is used, the CONTRACTOR shall furnish delivery
tickets at the time of delivery of each load of concrete. Each ticket shall show
the state certified equipment used for measuring and the total quantities, by
weight, of cement, sand, each class of aggregate, admixtures, and the
amounts of water in the aggregate added at the batching plant, and the amount
allowed to be added at the Site for the specific design mix. In addition, each
ticket shall state the mix number, total yield in cubic yards, and the time of day,
to the nearest minute, corresponding to the times when the batch was
dispatched, when it left the plant, when it arrived at the Site, when unloading
began, and when unloading was finished.
B. Other
1. The CONTRACTOR shall submit materials and methods for curing.
2. The CONTRACTOR shall submit product specifications, data, and installation
instructions for all miscellaneous products called for in this specification.
1.05 QUALIFICATIONS:
Truck mixers shall be equipped with electrically actuated counters by which the number of
revolutions of the drum or blades may be readily verified. The counter shall be of the resettable,
recording type, and shall be mounted in the driver's cab. The counters shall be actuated at the
time of starting mixers at mixing speeds.
1.06 CERTIFICATIONS AND TESTING:
A. General
1. Concrete and other materials for testing shall be furnished by the
CONTRACTOR, and the CONTRACTOR shall assist the ENGINEER in
obtaining samples, and disposal and cleanup of excess material.
2. The testing laboratory will meet or exceed the requirements of ASTM C 1077.
3. The cost of trial batch, laboratory, and shrinkage tests on cement, aggregates,
and concrete, will be the CONTRACTOR'S responsibility.
B. Trial Batch and Laboratory Tests
1. Tests for determining slump shall be in accordance with the requirements of
ASTM C 143.
2. Testing for aggregate shall include sand equivalence, reactivity, organic
impurities, abrasion resistance, and soundness, according to ASTM C 33.
3. A testing laboratory approved by the ENGINEER shall prepare a trial batch of
each class of concrete, based on the preliminary concrete mixes submitted by
the CONTRACTOR. During the trial batch the aggregate proportions may be
adjusted by the testing laboratory using the two coarse aggregate size ranges
to obtain the required properties. If one size range produces an acceptable
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mix, a second size range need not be used. Such adjustments will be
considered refinements to the mix design and will not be the basis for extra
compensation to the CONTRACTOR. Concrete shall conform to the
requirements of this Section, whether the aggregate proportions are from the
CONTRACTOR's preliminary mix design, or whether the proportions have
been adjusted during the trial batch process. The trial batch shall be prepared
using the aggregates, cement, and admixture proposed for the project. The
trial batch materials shall be of a quantity such that the testing laboratory can
obtain 3 drying shrinkage, and 6 compression test specimens from each batch.
4. The determination of compressive strength will be made by testing 6-inch
diameter by 12-inch high cylinders; made, cured and tested in accordance with
ASTM C 31 and ASTM C 39. Three compression test cylinders will be tested
at 7 days and 3 at 28 days. The average compressive strength for the 3
cylinders tested at 28 days for any given trial batch shall not be less than 125
percent of the indicated compressive strength.
5. A sieve analysis of the combined aggregate for each trial batch shall be
performed according to the requirements of ASTM C 136. Values shall be
given for percent passing each sieve.
C. Field Tests
1. The responsibility to retain the services of an independent testing laboratory
shall be as defined in SECTION 01410.
2. The CONTRACTOR shall pay the cost of any additional tests and investigation
on WORK that does not meet the specifications.
3. Tests on pumped concrete shall be taken at the point of final placement.
4. Compressive Test:
a. Compressive test specimens shall be taken during construction from the
first placement of each class of concrete placed each day and for each
150 cubic yards or fraction thereof each day.
b. Each set of test specimens shall consist of 5 cylinders. Specimens shall
be made in accordance with ASTM C 31. Specimens shall be 6-inch
diameter by 12-inch high cylinders.
c. Compression tests shall be performed in accordance with ASTM C 39.
Two (2) cylinders shall be broken at 7 days and two (2) at 28 days, and
the remaining cylinder shall be held to verify test results, if needed.
d. The acceptance of the test results shall be the average of the strengths of
the two specimens tested at 28 days as per ACI 318. Evaluation and
acceptance of the concrete shall be per ACI 318, Chapter 5.
5. Slump Tests: One (1) slump test shall be taken per truckload in accordance
with ASTM C 143.
6. Air Content: Air content shall be determined for each compressive test taken in
accordance with ASTM C 231 or by ASTM C 173.
7. Aggregate testing shall be made every 12 months during construction to insure
continued compliance with these Specifications.
8. Concrete that fails to meet the ACI requirements and these Specifications is
subject to removal and replacement.
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PART 2 - MATERIALS
2.01 GENERAL:
A. All materials shall be classified as acceptable for potable water use according to NSF
Standard 61.
B. Cement for concrete that will contact potable water shall not be obtained from kilns
that burn metal rich hazardous waste fuel.
C. Materials shall be delivered, stored, and handled so as to prevent damage by water
or breakage. Cement reclaimed from cleaning bags or leaking containers shall not
be used. Cement shall be used in the sequence of receipt of shipments.
D. Materials shall comply with the requirements of Sections 201, 203, and 204 of ACI
301, as applicable.
E. Storage of materials shall conform to the requirements of Section 205 of ACI 301.
2.02 CEMENT:
A. Cement shall be standard Portland Cement Type I conforming to ASTM C 150 A
minimum of 85 percent of cement by weight shall pass a 325 screen.
B. A single brand of cement shall be used throughout the WORK, and prior to its use,
the brand shall be accepted by the ENGINEER.
C. Sacked cement shall be stored in such a manner so as to permit access for
inspection and sampling. Certified mill test reports, including fineness, for each
shipment of cement to be used shall be submitted to the ENGINEER, if requested,
regarding compliance with these Specifications.
2.03 AGGREGATES:
A. Aggregates shall be obtained from pits acceptable to the ENGINEER, shall be non-
reactive, and shall conform to the requirements of ASTM C 33.
B. When tested in accordance with ASTM C 33, the loss resulting after 5 cycles of the
soundness test, shall not exceed 10 percent for fine aggregate and 12 percent for
coarse aggregate, when using sodium sulfate.
C. When tested in accordance with ASTM C 33, the ratio of silica released to reduction
in alkalinity shall not exceed 1.0.
D. Course Aggregates:
1. Coarse aggregates shall be crushed stone, gravel or other approved inert
material having clean, hard, durable, uncoated particles conforming to ASTM C
33.
2. The coarse aggregates shall be prepared and handled in 2 or more size
groups for combined aggregates with a maximum size greater than 3/4-inch.
When the aggregates are proportioned for each batch of concrete, the 2 size
groups shall be combined.
3. When tested in accordance with ASTM C 33, the coarse aggregate shall show
a loss not exceeding 42 percent after 500 revolutions, or 10.5 percent after 100
revolutions.
E. Fine Aggregates:
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1. Fine aggregates shall be clean sand conforming to ASTM C 33.
2. When tested in accordance with ASTM D 2419, the sand equivalency shall not
be less than 75 percent for an average of 3 samples, nor less than 70 percent
for an individual test. Gradation of fine aggregate shall conform to ASTM C 33
when tested in accordance with ASTM C 136 for the fineness modulus of the
sand used, including the optional grading in Section 6.2. The fineness
modulus of sand used shall not be over 3.1.
3. When tested in accordance with ASTM C 33, the fine aggregate shall produce
a color in the supernatant liquid no darker than the reference standard color
solution.
2.04 WATER:
A. The water used in the concrete mix and for curing shall be clean, potable, and in
accordance with ACI 318. Water shall be free from objectionable quantities of silty
organic matter, alkali, salts, and other impurities.
B. The water shall be considered potable, for the purposes of this Section only, if it
meets the requirements of the local governmental agencies. Agricultural water with
high total dissolved solids (over 1000 mg/l TDS) shall not be used.
2.05 ADMIXTURES:
A. General: All admixtures shall be compatible and be furnished by a single
manufacturer capable of providing qualified field service representation. Admixtures
shall be used in accordance with manufacturer's recommendations. If the use of an
admixture is producing an inferior end result, the CONTRACTOR shall discontinue
use of the admixture. Admixtures shall not contain thiocyanates nor more than 0.05
percent chloride ion, and shall be non-toxic after 30 days.
B. Air Entraining Admixtures:
1. Air entraining admixture shall conform to ASTM C 260. Air content shall be
tested at the point of placement.
2. The air-entraining agent shall be added to the batch in a portion of the mixing
water. The solution shall be batched by means of a mechanical batcher
capable of accurate measurement.
C. Set Controlling and Water Reducing Admixtures:
1. Admixtures may be added at the CONTRACTOR's option, subject to the
ENGINEER's approval, to control the set, effect water reduction, and increase
workability. The cost of adding an admixture shall be the CONTRACTOR's
responsibility. Concrete containing an admixture shall be first placed at a
location determined by the ENGINEER. Admixtures shall conform to the
requirements of ASTM C 494. The required quantity of cement shall be used
in the mix regardless of whether or not an admixture is used.
2. Concrete shall not contain more than one water-reducing admixture.
3. Set retarding admixture may be either with or without water-reducing
properties. Where the air temperature at the time of placement is expected to
be consistently greater than 80 degrees F, a set retarding admixture shall be
used. Set retarding admixture shall conform to ASTM C 494 Type B or D.
4. Set accelerating admixture may be either with or without water-reducing
properties. Where the air temperature at the time of placement is expected to
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be consistently less than 40 degrees F, a non-corrosive set accelerating
admixture shall be used. Set accelerating admixture shall conform to ASTM C
494 Type C or E.
5. Normal range water reducer shall conform to ASTM C 494, Type A. The
quantity of admixture used and the method of mixing shall be in accordance
with the manufacturer's instructions and recommendations.
6. High range water reducer shall conform to ASTM C 494, Type F or G. High
range water reducer shall be added to the concrete after all other ingredients
have been mixed and initial slump has been verified. No more than 14 ounces
of water reducer per sack of cement shall be used. Water reducer shall be
considered as part of the mixing water when calculating the water/cement ratio.
a. If the high range water reducer is added to the concrete at the Site, it may
be used in conjunction with the same water reducer added at the batch
plant. Concrete shall have a slump of 3 inches plus or minus 1/2-inch
prior to adding the high range water reducing admixture at the Site. The
high range water reducing admixture shall be accurately measured and
pressure injected into the mixer as a single dose by an experienced
technician. A standby system shall be provided and tested prior to each
day's operation of the primary system.
b. Concrete shall be mixed at mixing speed for a minimum of 70 mixer
revolutions or 5 minutes after the addition of the high range water
reducer, unless recommended otherwise by the manufacturer.
2.06 CURING MATERIALS:
A. Curing compound shall conform to ASTM C 309, Type I. Curing compound shall be
white pigmented, resin based and compliant with local VOC requirements. When
curing compound must be removed for finishes or grouting, it shall be of a dissipating
type. Sodium silicate compounds shall not be allowed.
B. Polyethylene sheet for use as concrete curing blanket shall be white and shall have a
nominal thickness of 6 mils. The loss of moisture when determined in accordance
with the requirements of ASTM C 156, shall not exceed 0.055 grams per square
centimeter of surface.
C. Polyethylene-coated waterproof paper sheeting for use as concrete curing blanket
shall consist of white polyethylene sheeting free of visible defects, uniform in
appearance, have a minimum thickness of 2 mils, and be permanently bonded to
waterproof paper conforming to the requirements of Federal Specification UU-B-
790A. The loss of moisture, when determined in accordance with the requirements
of ASTM C 156, shall not exceed 0.055 gram per square centimeter of surface.
D. Polyethylene-coated burlap for use as concrete curing blanket shall be minimum 4-
mil thick, white opaque polyethylene film impregnated or extruded into one side of
the burlap. Burlap shall weigh not less than 9 ounces per square yard. The loss of
moisture, when determined in accordance with the requirements of ASTM C 156,
shall not exceed 0.055 grams per square centimeter of surface.
E. Curing mats for use in Curing Method 6 below, shall be heavy shag rugs or carpets
or cotton mats quilted at 4-inches on center. Curing mats shall weigh a minimum of
12 ounces per square yard when dry.
2.07 MISCELLANEOUS MATERIALS:
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A. Damp proofing agent shall be an asphalt emulsion conforming to ASTM D1227, Type
III, Class 1.
B. Evaporation retardant shall create a monomolecular film on the concrete. The
retardant shall have no effect on cement hydration and shall meet local VOC
requirements. Evaporation retardant shall not effect adhesion of curing compounds
or other treatments and shall not effect the color of the concrete.
C. Reinforcement shall be per SECTION 03200 Concrete Reinforcement.
D. Water Stops shall be per SECTION 03100 Concrete Formwork.
E. Damp proofing agent shall be a waterborne emulsified-asphalt. Damp proofing shall
be suitable for "green" or slightly damp surfaces and shall withstand normal
expansion and contraction of the concrete. Damp proofing agent shall breath to
allow vapors to escape. Damp proofing agent shall meet local VOC requirements.
F. Bonding agents shall be 100% solids, epoxy adhesives conforming to the following:
1. For bonding freshly-mixed, plastic concrete to hardened concrete, bonding
agent shall be a medium viscosity adhesive conforming to ASTM C 881 Type
II, Grade 2, Class C,
2. For bonding hardened concrete or masonry to steel, bonding agent shall be a
non-sagging gel adhesive conforming to ASTM C 881 Type I or IV, Grade 3,
Class C.
G. Vapor Barrier:
1. Vapor Barrier shall consist of a composite of heavy kraft paper, asphalt,
fiberglass reinforcement, and polyethylene film. The composite shall be
laminated under heat and pressure.
2. Vapor Barrier shall comply with federal specification UU-B-790A, Type I, Grade
A, Style 4. Vapor Barrier shall have a water vapor permeance of less than 0.30
perms when tested per ASTM E 96.
3. Vapor Barrier shall be installed under concrete slabs of all habitable spaces.
Barrier shall be installed per the manufacturer recommendations and per
ASTM E 1643.
H. Non-Waterstop Joint Material:
1. Preformed Joint Material: Preformed asphalt-impregnated fiber conforming to
ASTM D 1751.
2. Bond Breaker: All bond breakers shall be roofing felt or 15 mils minimum dry
film thickness of bituminous paint as indicated.
2.08 CONCRETE DESIGN REQUIREMENTS:
A. General: Concrete shall be composed of cement, admixtures, aggregates, and
water of the qualities indicated. The exact proportions in which these materials are
to be used for different parts of the WORK will be determined during the trial batch
process. In general, the mix shall be designed to produce a concrete capable of
being deposited so as to obtain maximum density and minimum shrinkage, and,
where deposited in forms, to have good consolidation properties and maximum
smoothness of surface. The aggregate gradations shall be formulated to provide
fresh concrete that will not promote rock pockets around reinforcing steel or
embedded items. The proportions shall be changed whenever necessary or
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desirable to meet the required results. All changes shall be subject to review by the
ENGINEER.
B. Fine Aggregate Composition:
1. In mix designs for structural concrete, the percentage of fine aggregate in total
aggregate by weight, shall be as indicated in the following table.
Fine Aggregate
Fineness Modulus Maximum Percent
2.7 or less 41
2.7 to 2.8 42
2.8 to 2.9 43
2.9 to 3.1 44
2. For other concrete, the maximum percentage of fine aggregate of total
aggregate, by weight, shall not exceed 50.
C. Duct bank concrete shall contain an integral red-oxide coloring pigment. Concrete
shall be dyed red throughout. Surface treatment to color duct banks will not be
acceptable.
D. Water/Cement Ratio and Compressive Strength:
1. Water/cement ratio is given for aggregates in saturated-surface dry condition
and total moisture of all aggregates, calculated by ASTM C 566, less the
absorption of the aggregate as calculated by ASTM C 127 and C 128 shall
represent total free moisture in the aggregate determine the water/cement
ratio, total free moisture of aggregates shall be added to batch water to
estimate water content of concrete. Concrete shall have the following
minimum properties:
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E. Adjustments to Mix Design: The CONTRACTOR may elect to decrease the
water/cement ratio to achieve the strength and shrinkage requirements and/or add
water reducers, as required to achieve workability. The mixes shall be changed
whenever such change is necessary or desirable to secure the required strength,
density, workability, and surface finish, and the CONTRACTOR shall be entitled to no
additional compensation because of such changes. Any changes to the accepted
concrete mix design shall be submitted to the ENGINEER for review and shall be
tested again in accordance with these Specifications.
F. When using a floor hardener the water/cement ratio shall not be greater than
specified by the hardener manufacturer.
2.09 CONSISTENCY:
A. The quantity of water in a batch of concrete shall be just sufficient, with a normal
mixing period, to produce a concrete which can be worked properly into place
without segregation and which can be compacted by vibratory methods to give the
desired density, impermeability, and smoothness of surface. The quantity of water
shall be changed as necessary, with variations in the nature or moisture content of
the aggregates, to maintain uniform production of a desired consistency. The
consistency of the concrete in successive batches shall be determined by slump
tests in accordance with ASTM C 143 The slumps shall be as follows:
Part of Work Slump (in)
All concrete, unless indicated
otherwise
3-inches plus or minus 1-inch
With high range water reducer
added
7-inches plus or minus 2-inches
Pea gravel mix 7-inches plus or minus 2-inches
Ductbank and pipe encasement 5-inches plus or minus 1-inch
Concrete with hardener Per Hardener Manufacturer
2.10 MEASUREMENT:
A. The amount of cement and of each separate size of aggregate entering into each
batch of concrete shall be determined by direct weighing equipment furnished by the
CONTRACTOR and acceptable to the ENGINEER.
B. Weighing tolerances
Material Percent of Total
Weight
Cement 1
Aggregates 3
Admixtures 3
C. The quantity of water entering the mixer shall be measured by a suitable water meter
or other measuring device of a type acceptable to the ENGINEER and capable of
measuring the water in variable amounts within a tolerance of one percent. The
water feed control mechanism shall be capable of being locked in position so as to
deliver constantly any required amount of water to each batch of concrete. A positive
quick-acting valve shall be used for a cut-off in the water line to the mixer. The
operating mechanism shall prevent leakage when the valves are closed.
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PART 3 - EXECUTION
3.01 PROPORTIONING AND MIXING:
A. Proportioning of the mix shall conform to the requirements of Chapter 3
"Proportioning" of ACI 301.
B. Mixing shall conform to the requirements of Chapter 7 of ACI 301.
C. Slumps shall be as indicated herein.
D. Retempering of concrete or mortar that has partially hardened shall not be permitted.
3.02 PREPARATION OF SURFACES FOR CONCRETING:
A. General: Earth surfaces shall be thoroughly wetted by sprinkling prior to the placing
of any concrete, and these surfaces shall be kept moist by frequent sprinkling up to
the time of placing concrete thereon. The surface shall be free from standing water,
mud, and debris at the time of placing concrete.
B. Vapor Barrier
1. Vapor Barrier shall be installed under on-grade building floor slabs of
occupiable (non-hydraulic) structures and at other locations indicated.
2. Base shall be leveled, compacted, and tamped per SECTION 02200
Earthwork. Remove sharp edges, projection materials and roughness that
might penetrate vapor barrier. Install barrier with width parallel with the
direction of the pour of the concrete.
3. Place, protect, and repair defects in sheet according to ASTM E 1643, and the
manufacturer's written instructions. Seams shall be lapped and sealed in
accordance with ASTM E 1643.
4. The CONTRACTOR shall exercise care to avoid puncturing or tearing the
vapor barrier during installation. Patch punctures and tears as they occur.
C. Joints in Concrete:
1. All joints shall be installed where indicated on the Drawings or where otherwise
approved by the Engineer. The surface of the construction joint shall be rough
and prior to placement shall be cleaned and moistened with water.
2. Concrete surfaces upon or against which concrete is to be placed, where the
placement of the concrete has been stopped or interrupted so that, as
determined by the ENGINEER, the new concrete cannot be incorporated
integrally with that previously placed, are defined as construction joints. The
surfaces of horizontal joints shall be given a compacted, roughened surface for
good bonding. Except where the Drawings call for joint surfaces to be coated,
the joint surfaces shall be cleaned of all laitance, loose or defective concrete,
foreign material, and be roughened to a minimum 1/4-inch amplitude. Such
cleaning and roughening shall be accomplished by hydroblasting or
sandblasting (exposing aggregate) followed by thorough washing. Pools of
water shall be removed from the surface of construction joints before the new
concrete is placed.
3. After the surfaces have been prepared, all approximately horizontal
construction joints shall be covered with a 6-inch lift of a pea gravel mix. The
mix shall be placed and spread uniformly. Wall concrete shall follow
immediately and shall be placed upon the fresh pea gravel mix. If high range
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water reducer is used in the wall concrete, then the pea gravel joint topping
does not need to be used.
D. Placing Interruptions: When placing of concrete is to be interrupted long enough for
the concrete to take a set, the working face shall be given a shape by the use of
forms or other means that will secure proper union with subsequent work; provided
that construction joints shall be made only where acceptable to the ENGINEER.
E. Embedded Items:
1. No concrete shall be placed until all formwork, installation of parts to be
embedded, reinforcement steel, and preparation of surfaces involved in the
placing have been completed and accepted by the ENGINEER at least 4 hours
before placement of concrete. Surfaces of forms and embedded items that
have become encrusted with dried grout from previous usage shall be cleaned
before the surrounding or adjacent concrete is placed.
2. Inserts or other embedded items shall conform to the requirements herein.
3. Reinforcement, anchor bolts, sleeves, inserts, and similar items shall be set
and secured in the forms at locations indicated on the Drawings or shown by
Shop Drawings and shall be acceptable to the ENGINEER before any concrete
is placed. Accuracy of placement is the responsibility of the CONTRACTOR.
F. Casting New Concrete Against Old: Where concrete is to be cast against old
concrete (any concrete which is greater than 60 days of age), the surface of the old
concrete shall be thoroughly cleaned and roughened by hydroblasting or
sandblasting to expose aggregate. The joint surface shall be coated with an epoxy
bonding agent unless indicated otherwise by the ENGINEER.
G. No concrete shall be placed in any structure until all water entering the space to be
filled with concrete has been properly cut off or has been diverted by pipes, or other
means, and carried out of the forms, clear of the WORK. No concrete shall be
deposited underwater nor shall the CONTRACTOR allow still water to rise on any
concrete until the concrete has attained its initial set. Water shall not be permitted to
flow over the surface of any concrete in such manner and at such velocity as will
injure the surface finish of the concrete. Pumping or other necessary dewatering
operations for removing ground water, if required, shall be subject to the review of
the ENGINEER.
H. Corrosion Protection: Pipe, conduit, dowels, and other ferrous items required to be
embedded in concrete construction shall be so positioned and supported prior to
placement of concrete that there will be a minimum of 2-inches clearance between
said items and any part of the concrete reinforcement. Securing such items in
position by wiring or welding them to the reinforcement will not be permitted.
I. Openings for pipes, inserts for pipe hangers and brackets, and anchors shall, where
practicable, be provided during the placing of concrete.
J. Anchor bolts shall be accurately set and shall be maintained in position by templates
while being embedded in concrete.
K. Cleaning: The surfaces of metalwork to be in contact with concrete shall be
thoroughly cleaned of all dirt, grease, loose scale and rust, grout, mortar, and other
foreign substances immediately before the concrete is placed.
3.03 CONVEYING:
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A. Concrete shall be conveyed from the mixer to the place of final deposit by methods
that will prevent separation or loss of material.
B. No aluminum materials shall be used in conveying any concrete.
C. Ends of chutes, hopper gates, and all other points of concrete discharge throughout
the CONTRACTOR'S conveying, hoisting, and placing system shall be designed and
arranged so that concrete passing from them will not fall separated into whatever
receptacle immediately receives it. Conveyor belts, if used, shall be of a type
acceptable to the ENGINEER. Chutes longer than 50 feet will not be permitted.
Minimum slopes of chutes shall be such that concrete of the indicated consistency
will readily flow in them. If a conveyor belt is used, it shall be wiped clean by a
device operated in such a manner that none of the mortar adhering to the belt will be
wasted. All conveyor belts and chutes shall be covered.
D. Pumping:
1. If the pumped concrete does not produce satisfactory end results, the
CONTRACTOR shall discontinue the pumping operation and proceed with the
placing of concrete using conventional methods.
2. The pumping equipment shall have 2 cylinders and be designed to operate
with one cylinder in case the other one is not functioning. In lieu of this
requirement, the CONTRACTOR may have a standby pump on the Site during
pumping.
3. The minimum diameter of the hose conduits shall be in accordance with ACI
304.
4. Pumping equipment and hose conduits that are not functioning properly shall
be replaced.
5. Aluminum conduits for conveying the concrete shall not be permitted.
6. Concrete samples for slump, air content, and test cylinders will be taken at the
placement end of the hose.
3.04 DELIVERY:
A. Ready-mixed concrete shall be batched, mixed, transported and delivered in
accordance with these specifications and ASTM C 94 including the following
supplementary requirements.
1. Concrete shall be discharged within 1-1/2 hours from the time concrete was
mixed, if centrally mixed, or from the time the original water was added, if
transit-mixed or before the drum has been revolved 300 revolutions, whichever
is first.
2. Truck mixers and their operation shall be such that the concrete throughout the
mixed batch as discharged is within acceptable limits of uniformity with respect
to consistency, mix, and grading. If slump tests taken at approximately the 1/4
and 3/4 points of the load during discharge give slumps differing by more than
one-inch when the required slump is 3-inches or less, or if they differ by more
than 2-inches when the required slump is more than 3-inches, the mixer shall
not be used on the WORK unless the causative condition is corrected and
satisfactory performance is verified by additional slump tests. Mechanical
details of the mixer, such as water measuring and discharge apparatus,
condition of the blades, speed of rotation, general mechanical condition of the
03300 - 14/22
unit, and clearance of the drum, shall be checked before a further attempt to
use the unit will be permitted.
3. The use of non-agitating equipment for transporting ready-mixed concrete will
not be permitted. The quality and quantity of materials used in ready-mixed
concrete and in batch aggregates shall be subject to continuous inspection at
the batching plant by the ENGINEER.
4. Each batch of concrete shall be mixed in a truck mixer for not less than 70
revolutions of the drum or blades at the rate of rotation designated by the
manufacturer of equipment. Additional mixing, if any, shall be at the speed
designated by the manufacturer of the equipment as agitating speed. All
materials including mixing water shall be in the mixer drum before actuating the
revolution counter for determining the number of revolution of mixing.
3.05 PLACING:
A. Non-Conforming Work or Materials: Concrete which during or before placing is
found not to conform to the requirements indicated herein shall be rejected and
immediately removed from the WORK. Concrete which is not placed in accordance
with these Specifications, or which is of inferior quality, shall be removed and
replaced.
B. Unauthorized Placement: No concrete shall be placed except in the presence of a
duly authorized representative of the ENGINEER. The CONTRACTOR shall notify
the ENGINEER in writing at least 24 hours in advance of placement of any concrete.
C. Concrete shall not be dropped more than four feet (4’) without use of chutes or
tremies. Concreting shall be a continuous operation until placement of the section is
complete. All concrete shall be worked around reinforcement and embedded items.
If vibrators are used, care shall be taken not to segregate concrete. Vibrators will not
be allowed to move concrete within the form. All forms and subgrade shall be
dampened prior to placement and excess water removed.
D. Placing of concrete shall conform to the applicable requirements of Chapter 8 of ACI
301 and the requirements of this Section.
E. Placement in Slabs: Concrete placed in sloping slabs shall proceed uniformly from
the bottom of the slab to the top, for the full width of the placement. As the work
progresses, the concrete shall be vibrated and carefully worked around the slab
reinforcement, and the surface of the slab shall be screeded in an up-slope direction.
F. Concrete shall not be dropped through reinforcement steel or into any deep form, nor
shall concrete be placed in any form in such a manner as to leave accumulation of
mortar on the form surfaces above the placed concrete. In such cases, means such
as hoppers and, if necessary, vertical ducts of canvas, rubber, or metal shall be used
for placing concrete in the forms in a manner that it may reach the place of final
deposit without separation. Concrete shall be uniformly distributed during the
process of depositing and in no case after depositing shall any portion be displaced
in the forms more than 6-feet in horizontal direction. Concrete in wall forms shall be
deposited in uniform horizontal layers not deeper than 2-feet; and care shall be taken
to avoid inclined layers or inclined construction joints except where such are required
for sloping members. Each layer shall be placed while the previous layer is still soft.
The rate of placing concrete in wall forms shall not exceed 5-feet of vertical rise per
hour. Sufficient illumination shall be provided in the interior of all forms so that the
concrete at the places of deposit is visible from the deck or runway.
03300 - 15/22
G. Concrete with hardener shall be placed per the hardener manufacturers written
recommendations.
H. Casting New Concrete Against Old: Epoxy adhesive bonding agent shall be applied
to the old surfaces according to the manufacturer's written recommendations. This
provision shall not apply to joints where waterstop is provided, see SECTION 03100
Concrete Formwork.
I. Temperature of Concrete: The temperature of concrete when it is being placed shall
be not more than 90 degrees F nor less than 55 degrees F for sections less than 12-
inches thick nor less than 50 degrees for all other sections. The CONTRACTOR
shall be entitled to no additional compensation on account of the temperature
requirements.
J. Hot Weather Placement
1. Placement of concrete in hot weather shall conform to ACI 305 and the
following:
2. When the temperature of the concrete is 85 degrees F or above, the time
between the introduction of the cement to the aggregates and discharge shall
not exceed [60] minutes.
3. If concrete is placed when the weather is such that the temperature of the
concrete would exceed 90 degrees F, the CONTRACTOR shall employ
effective means, such as pre-cooling of aggregates and mixing water using ice
or placing at night, as necessary to maintain the temperature of the concrete
below 90 degrees F as it is placed.
K. Cold Weather Placement
1. Placement of concrete in cold weather shall conform to ACI 306.1, and the
following:
2. Concrete ingredients shall not be heated to a temperature higher than that
necessary to keep the temperature of the mixed concrete, as placed, from
falling below the minimum temperature.
3. Remove all snow, ice, and frost from the surfaces, including reinforcement,
against which concrete is to be placed. Before beginning concrete placement,
thaw the subgrade to a minimum depth of 6-inches. Reinforcement and
embedded items shall be warmed to above 32 degrees F prior to concrete
placement.
4. Maintain the concrete temperature above 50 degrees F for at least 72 hours
after placement.
L. Order of Placing Concrete
1. The order of placing concrete in all parts of the WORK shall be acceptable to
the ENGINEER. In order to minimize the effects of shrinkage, the concrete
shall be placed in units as bounded by construction joints at the indicated
locations. The placing of units shall be done by placing alternate units in a
manner such that each unit placed shall have cured at least 5 days for
hydraulic structures and 2 days for all other structures before the contiguous
unit or units are placed, except that the corner sections of vertical walls shall
not be placed until the 2 adjacent wall panels have cured at least 10 days for
hydraulic structures and 4 days for all other structures.
03300 - 16/22
2. The surface of the concrete shall be level whenever a run of concrete is
stopped. To insure a level, straight joint on the exposed surface of walls, a
wood strip at least 3/4-inch thick shall be tacked to the forms on these
surfaces. The concrete shall be carried about 1/2-inch above the underside of
the strip. About one hour after the concrete is placed, the strip shall be
removed and any irregularities in the edge formed by the strip shall be leveled
with a trowel and laitance shall be removed.
3.06 TAMPING AND VIBRATING:
A. As concrete is placed in the forms or in excavations, it shall be thoroughly settled
and compacted throughout the entire depth of the layer which is being consolidated,
into a dense, homogeneous mass, filling all corners and angles, thoroughly
embedding the reinforcement, eliminating rock pockets, and bringing only a slight
excess of water to the exposed surface of concrete. Vibrators shall be Group 3 per
ACI 309, high speed power vibrators (8000 to 12,000 rpm) of an immersion type in
sufficient number and with at least one standby unit as required. Group 2 vibrators
may be used only at specific locations when accepted by the ENGINEER.
B. Care shall be used in placing concrete around waterstops. The concrete shall be
carefully worked by rodding and vibrating to make sure that all air and rock pockets
have been eliminated. Where flat-strip type waterstops are placed horizontally, the
concrete shall be worked under the waterstops by hand, making sure that air and
rock pockets have been eliminated. Concrete surrounding the waterstops shall be
given additional vibration over and above that used for adjacent concrete placement
to assure complete embedment of the waterstops in the concrete.
C. Concrete in walls shall be internally vibrated and at the same time rammed, stirred,
or worked with suitable appliances, tamping bars, shovels, or forked tools until it
completely fills the forms or excavations and closes snugly against all surfaces.
Subsequent layers of concrete shall not be placed until the layers previously placed
have been worked thoroughly. Vibrators shall be provided in sufficient numbers, with
standby units as required, to accomplish the required results within 15 minutes after
concrete of the prescribed consistency is placed in the forms. The vibrating head
shall not contact the surfaces of the forms. Care shall be taken not to vibrate
concrete excessively or to work it in any manner that causes segregation of its
constituents.
3.07 CURING AND DAMPPROOFING: Concrete shall be cured for a minimum of five (5) days
after placement in accordance with the methods indicated below for the different parts of
the WORK.
A. The surface shall be sprayed with a liquid curing compound.
1. It shall be applied in accordance with the manufacturer's printed instructions at
a maximum coverage rate of 200 square feet per gallon and in such a manner
as to cover the surface with a uniform film that will seal thoroughly.
2. Where the curing compound method is used, care shall be exercised to avoid
damage to the seal during the 7-day curing period. If the seal is damaged or
broken before the expiration of the curing period, the break shall be repaired
03300 - 17/22
immediately by the application of additional curing compound over the
damaged portion.
3. Wherever curing compound has been applied by mistake to surfaces against
which concrete subsequently is to be placed and to which it is to adhere,
compound shall be entirely removed by wet sandblasting just prior to the
placing of new concrete.
4. Curing compound shall be applied as soon as the concrete has hardened
enough to prevent marring on unformed surfaces and within 2 hours after
removal of forms. Repairs to formed surfaces shall be made within the 2 hour
period; provided, however, that any such repairs which cannot be made within
the said 2 hour period shall be delayed until after the curing compound has
been applied. When repairs are to be made to an area on which curing
compound has been applied, the area involved shall first be wet-sandblasted
to remove the curing compound.
5. At locations where concrete is placed adjacent to a panel which has been
coated with curing compound, the panel shall have curing compound reapplied
to an area within 6-feet of the joint and to any other location where the curing
membrane has been disturbed.
6. Prior to final acceptance of the WORK, all visible traces of curing compound
shall be removed from all surfaces in such a manner that does not damage the
surface finish.
B. For slabs on grade:
1. Until the concrete surface is covered with curing compound, the entire surface
shall be kept damp by applying water using nozzles that atomize the flow so
that the surface is not marred or washed. The concrete shall be given a coat
of curing compound in accordance with paragraph A above. Not less than one
hour nor more than 4 hours after the curing compound has been applied, the
surface shall be wetted with water delivered through a fog nozzle, and
concrete-curing blankets shall be placed on the slabs. The curing blankets
shall be polyethylene sheet, polyethylene-coated waterproof paper sheeting, or
polyethylene-coated burlap. The blankets shall be laid with the edges butted
together and with the joints between strips sealed with 2-inch wide strips of
sealing tape or with edges lapped not less than 3-inches and fastened together
with a waterproof cement to form a continuous watertight joint.
2. The curing blankets shall be left in place during the 7-day curing period and
shall not be removed until after concrete for adjacent work has been placed. If
the curing blankets become torn or otherwise ineffective, the CONTRACTOR
shall replace damaged sections. During the first 3 days of the curing period,
no traffic of any nature and no depositing, temporary or otherwise, of any
materials shall be permitted on the curing blankets. During the remainder of
the curing period, foot traffic and temporary depositing of materials that impose
light pressure will be permitted only on top of plywood sheets 5/8-inch
minimum thickness, laid over the curing blanket. The CONTRACTOR shall
add water under the curing blanket as often as necessary to maintain damp
concrete surfaces at all times.
C. Damp proofing
1. The exterior surfaces of backfilled dry well walls and buried roof slabs shall be
damp proofed as follows.
03300 - 18/22
2. Immediately after completion of curing the surface shall be sprayed with a
damp proofing agent consisting of an asphalt emulsion. Application shall be in
2 coats. The first coat shall be diluted to one-half strength by the addition of
water and shall be sprayed on so as to provide a maximum coverage rate of
100 square feet per gallon of dilute solution. The second coat shall consist of
an application of the undiluted material, and shall be sprayed on so as to
provide a maximum coverage rate of 100 square feet per gallon. Damp
proofing material shall be as indicated above.
3. As soon as the material has taken an initial set, the entire area thus coated
shall be coated with whitewash. Any formula for mixing the whitewash may be
used if it produces a uniformly coated white surface and remains until placing
of the backfill. If the whitewash fails to remain on the surface until the backfill
is placed, the CONTRACTOR shall apply additional whitewash.
3.08 CONCRETE FINISHES:
A. General: Surfaces shall be free from fins, bulges, ridges, offsets, honeycombing, or
roughness of any kind, and shall present a finished, smooth, continuous hard
surface. Allowable deviations from plumb or level and from the alignment, profiles,
and dimensions indicated are defined as tolerances and are indicated herein. These
tolerances are to be distinguished from irregularities in finish as described herein.
Aluminum finishing tools shall not be used.
B. Formed Surfaces:
1. No treatment is required after form removal except for curing, repair of
defective concrete, and treatment of surface defects. Where architectural
finish is required, it shall be as indicated.
C. Unformed Surfaces:
1. After proper and adequate vibration and tamping, unformed top surfaces of
slabs, floors, walls, and curbs shall be brought to a uniform surface with
suitable tools. Immediately after the concrete has been screeded, it shall be
treated with a liquid evaporation retardant. The retardant shall be used again
after each work operation as necessary to prevent drying shrinkage cracks.
The classes of finish for unformed concrete surfaces are designated and
defined as follows:
Unformed Surface Finish Schedule
Area Finish
Grade slabs and foundations to be covered with
concrete or fill material U1
Floors to be covered with grouted tile or topping grout U2
Water bearing slabs with slopes 10 percent and less U3
Water bearing slabs with slopes greater than 10
percent U4
Slabs not water bearing U4
Slabs to be covered with built-up roofing U2
Interior slabs and floors to receive architectural finish U3
Top surface of walls subject to foot traffic U4
Top surface of walls not subject to foot traffic U3
Floors to receive surface hardener U5
03300 - 19/22
2. Finish U1 - Sufficient leveling and screeding to produce an even, uniform
surface with surface irregularities not to exceed 3/8-inch. No further special
finish is required.
3. Finish U2 - (Float Finish)
a. Compact, accurately screed and float to a true uniform surface.
b. Surfaces shall be floated with wood or metal floats or a finishing machine
using float blades. Excessive floating of surfaces while the concrete is
plastic and dusting of dry cement and sand on the concrete surface to
absorb excess moisture will not be permitted.
c. Floating shall be the minimum necessary to produce a surface that is free
from screed marks and is uniform in texture. Test surface with
straightedge and eliminate high and low spots of more than 1/8 inch in 10
feet. Surface irregularities shall not exceed 1/4-inch.
d. Joints and edges shall be tooled where indicated or as determined by the
ENGINEER.
4. Finish U3 - (Hand-Troweled Finish)
a. Finish surface as in Finish U2 - Float Finish and after the surface has
hardened sufficiently to prevent excess of fine material from being drawn
to the surface, trowel with steel trowel to obtain a smooth dense finish
after concrete has hardened to ring under the trowel.
b. The finish shall be produce a smooth dense uniform surface free of all
irregularities, blemishes, ripples, and trowel marks.
5. Finish U4 - (Nonskid Finish)
a. Trowel the Finish U3 - Hand-trowelled Finish surface to remove local
depressions or high points. In addition, the surface shall be given a light
broom finish with brooming perpendicular to drainage unless otherwise
indicated.
b. The resulting surface shall be rough enough to provide a nonskid finish.
6. Finish U5 - (Surface hardener)
a. Immediately after screeding, shake on hardener shall be applied per the
manufacturer's written recommendations.
b. Surface shall receive a minimum of two coats of a liquid hardener per the
manufacturer's written recommendations.
3.09 ARCHITECTURAL FINISH:
A. General: Architectural finishes shall be provided only where specifically indicated
below. In all other locations, the paragraph entitled Concrete Finishes shall apply.
B. Immediately after the forms have been stripped, the concrete surface shall be
inspected and any poor joints, voids, rock pockets, or other defective areas shall be
repaired and form-tie holes filled as indicated herein.
C. Architectural finishes shall not be applied until the concrete surface has been
repaired as required and the concrete has cured at least 14 days.
D. Architecturally treated concrete surfaces shall conform to the accepted sample in
texture, color, and quality. It shall be the CONTRACTOR's responsibility to maintain
and protect the concrete finish.
03300 - 20/22
E. Burlap Finish:
1. Wet and fill all voids using mortar with the same sand-cement ratio as original
concrete. Use approximately 20 percent white cement to match concrete color.
2. The freshly applied grout shall be vigorously rubbed into the concrete surface
with a wood float filling all small air holes. After all the surface grout has been
removed with a steel trowel, the surface shall be allowed to dry.
3. Once dry, strike off all excess mortar flush with the surface using a burlap or
canvas cloth with a circular motion.
4. Remove all rough spots and rub with cloth to leave a surface of uniform texture
and appearance without any appearance of a paint or grout film.
5. Finish shall result in a coating of mortar that will fill all small voids and air holes,
leaving a smooth surface.
6. Cure as specified under "Curing Concrete".
7. The entire cleaning operation for any area shall be completed the day it is
started, and no grout shall be left on the surface overnight.
8. Cleaning operations for any given day shall be terminated at panel joints. It is
required that the various operations be carefully timed to secure the desired
effect.
9. Before beginning any of the final treatment on exposed surfaces, the
CONTRACTOR shall treat in a satisfactory manner a trial area of at least 200
square feet in some inconspicuous place selected by the ENGINEER and shall
preserve said trial area undisturbed until the completion of the job.
F. Sandblasted Concrete Finish
1. Sandblasting shall be done in a safe manner acceptable to local authorities
and per OSHA requirements. The sandblasting shall be a light sandblast to
remove laitance and to produce a uniform fine aggregate surface texture with
approximately 1/32- to 1/16-inch of surface sandblasted off. Corners, patches,
form panel joints, and soft spots shall be sandblasted with care.
2. A 3-sq ft sample panel of the sandblasted finish shall be provided by the
CONTRACTOR for acceptance by the ENGINEER prior to starting the
sandblasting work. The sample panel shall include a corner, plugs, and joints
and shall be marked after approval. All other sandblasting shall be equal in
finish to the sample panel.
3. Protection against sandblasting shall be provided on all adjacent surfaces and
materials not requiring sandblasting. After sandblasting, the concrete surfaces
shall be washed with clean water and excess sand removed.
3.10 PROTECTION:
A. The CONTRACTOR shall protect concrete against injury until final acceptance.
B. Fresh concrete shall be protected from damage due to rain, hail, sleet, or snow. The
CONTRACTOR shall provide such protection while the concrete is still plastic and
whenever precipitation is imminent or occurring.
3.11 DEFECTIVE SURFACE TREATMENTS:
A. Patching Concrete:
03300 - 21/22
1. Patch all tie holes, honeycombs or other defects with a Portland Cement and
sand grout.
2. Defective surfaces to be repaired shall be cut back from trueline a minimum
depth of 1/2-inch over the entire area. Feathered edges will not be permitted.
Where chipping or cutting tools are not required in order to deepen the area
properly, the surface shall be prepared for bonding by the removal of all
laitance or soft material, plus not less than 1/32-inch depth of the surface film
from all hard portions by means of an efficient sandblast.
3. After cutting and sandblasting, the surface shall be wetted sufficiently in
advance of shooting with shotcrete or with cement mortar so that while the
repair material is being applied, the surfaces underneath will remain moist but
not so wet as to overcome the suction upon which a good bond depends.
4. Holes left by tie-rod cones shall be reamed with suitable toothed reamers so as
to leave the surfaces of the holes clean and rough. Holes then shall be
repaired in an approved manner with dry-packed cement grout. Holes left by
form-tying devices having a rectangular cross-section and other imperfections
having a depth greater than their least surface dimension shall not be reamed
but shall be repaired in an approved manner with dry-packed cement grout.
5. The grout shall not be richer than one (1) part cement and three (3) parts sand
with the amount of mixing water enough to produce a workable mix. For
exposed walls, the cement shall contain such a proportion of white portland
cement as is required to make the color of the patch match the color of the
surrounding concrete. The patch shall be finished in such a manner as to
match the adjoining surfaces.
6. Surfaces of repairs shall receive the same kind and amount of curing treatment
as required for the concrete in the repaired section.
B. Defective Concrete:
1. Any concrete which is not formed as shown on the Drawings or does not
conform to the Contract tolerances or shows defects which reduce its structural
adequacy, shall be removed from the job by the CONTRACTOR at his
expense unless the Engineer grants permission to patch the defective area.
C. Exposed Concrete Surfaces:
1. As soon as forms are removed, exposed surfaces shall be carefully examined
and all ridges, ribs and other imperfections shall be rubbed with an abrasive
stone or ground in a satisfactory manner in order to secure a smooth, uniform
and continuous surface. Plastering or coating of surfaces to be smoothed will
not be permitted
2. No repairs shall be made until after inspection by the ENGINEER.
3. In no case will extensive patching of honeycombed concrete be permitted
4. Concrete containing minor voids, pinholes, honeycombing, or similar
depression defects shall be repaired as indicated below.
5. Concrete containing extensive voids, holes, honeycombing, or similar
depression defects shall be completely removed and replaced. Repairs and
replacements shall be performed promptly.
03300 - 22/22
3.12 REINFORCEMENT: Reinforcement shall be in accordance with SECTION 03200
Concrete Reinforcement, of these Specifications. Concrete protection for the
reinforcement shall conform to the requirements ACI 318, paragraph 7.7.1.
3.13 CONSTRUCTION TOLERANCES:
A. The CONTRACTOR shall set and maintain concrete forms and perform finishing
operations to ensure that the completed WORK is within tolerances. Surface defects
and irregularities are defined as finishes and are to be distinguished from tolerances.
Tolerance is the permissible variation from lines, grades, or dimensions indicated on
the Drawings. Where tolerances are not stated in the specifications, permissible
deviations will be in accordance with ACI 117.
3.14 CARE AND REPAIR OF CONCRETE:
A. The CONTRACTOR shall protect concrete against injury or damage from excessive
heat, lack of moisture, overstress, or any other cause until final acceptance.
Particular care shall be taken to prevent the drying of concrete and to avoid
roughening or otherwise damaging the surface. Any concrete found to be damaged,
or which may have been originally defective, or which becomes defective at any time
prior to the final acceptance of the completed WORK, or which departs from the
established line or grade, or which, for any other reason, does not conform to the
requirements of the Contract Documents, shall be satisfactorily repaired or removed
and replaced with acceptable concrete.
END OF SECTION