Final 03 30 00.pdf

OFFUTT AIR FORCE BASE

03 30 00-1 (092036) (Repair AHU O-Club, B462)

2010 by FEI

SECTION 03 30 00

CAST - IN - PLACE CONCRETE

PART 1 - GENERAL

1.1 SCOPE

A. This section of the specifications covers the provision of all labor, materials, tools, equipment, and the performance of all work and services necessary or incidental to provide and place all cast - in - place concrete as shown on the drawings and as specified, and completely coordinated with the work of all other trades.

B. Although such work may not be specifically shown or specified, provide and install all supplementary and/or miscellaneous items, appurtenances and devices incidental to or necessary for a sound, secure and complete installation.

1.2 CODES, SPECIFICATIONS AND STANDARDS

A. Any material or operation specified by reference to the published specifications of a manufacturer or other referenced code, specification or standard shall comply with the requirements of the latest edition (i.e., the latest published edition at time of bidding). In case of a conflict between a referenced code, specification, or standard and these project specifications, the more stringent requirement shall govern.

B. Comply with the applicable provisions of the codes, specifications, and standards published by the following organizations to the extent indicated by reference thereto:

1. ACI "American Concrete Institute"

2. ASTM "American Society for Testing and Materials"

C. The restatement herein of certain portions of referenced codes, specifications, and standards shall not be interpreted as a de emphasis of other portions of the referenced material.

D. Concrete work shall comply with the requirements of ACI 301 except as modified by this specification.

1.3 RELATED SECTIONS

A. Sealant specification is found elsewhere in Division 07.

1.4 SUBMITTALS

A. Substitutions and / or modifications and the reasons therefore shall be submitted for review prior to the submission of other submittal items. The contractor is cautioned however that only under extraordinary circumstances will substitutions and/or modifications be allowed.

B. Certified copies of the concrete design mix shall be submitted for review.

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PART 2 - PRODUCTS

2.1 MATERIALS

A. Only one brand of any one type of cement shall be used for exposed concrete surfaces of any individual structure. High early strength portland cement may be used only with the written approval of the Contracting Officer’s Representative.

1. Portland cement shall meet the requirements of ASTM C150 (Type I).

2. High early strength Portland cement shall meet the requirements of ASTM C150 (Type III).

B. Water shall be potable.

C. Aggregate shall conform to the requirements of ASTM C33 except as amended herein. Coarse aggregate shall be well graded from fine to coarse within the prescribed limits. Maximum nominal coarse aggregate size shall be 3/4 inch in maximum nominal size.

1. Aggregate, both fine and coarse, shall conform to the standards of the Nebraska Department of Roads for aggregate for Class 47 B concrete as shown in tables below: ONLY

AGGREGATE BELOW THE 3/4 INCH SIZE SHALL BE USED!

FINE AGGREGATE FOR CONCRETE GRADATION LIMITS

CLASS B AGGREGATE AS USED IN CLASS 47B CONCRETE

Sieve Size

Target Value (Percent)

Tolerance

1 Inch

None

No. 4

No.10

No. 30

No. 200

1.5

Sizes shown are a part of gradation chart but are not to be used in actual concrete mix.

COARSE AGGREGATE FOR CONCRETE GRADATION LIMITS

CLASS E AGGREGATE AS USED IN CLASS 47B CONCRETE

Sieve Size

Target Value (Percent)

Tolerance

11/2 Inch

None

1 Inch

3/4 inch

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COARSE AGGREGATE FOR CONCRETE GRADATION LIMITS

CLASS E AGGREGATE AS USED IN CLASS 47B CONCRETE

3/8 inch

No. 4

No. 20

2*

No. 200

* The percent passing may be increased to 33 provided no more than 1.5% is passing the No. 200 sieve when washed.

Sizes shown are a part of gradation chart but are not to be used in actual concrete mix.

2. ASTM Specification C 33: Coarse aggregate shall be well graded from fine to coarse within the prescribed limits. Maximum nominal coarse aggregate size shall be 3/4 inch in maximum nominal size. All coarse aggregate shall be limestone. All concrete shall contain a minimum of 30 percent limestone.

D. Concrete Admixtures shall be as listed below:

1. All concrete shall receive an air entraining admixture in accordance with manufacturer's specifications and ASTM C 260. Total air entrained shall be as specified hereinafter and determined in accordance with ASTM C 233.

2. Corrective additions to remedy deficiencies in aggregate grading may be used only with the written approval of the Contracting Officer’s Representative.

3. Set retarding admixture for hot weather concreting may be used only with the written approval of the Contracting Officer’s Representative.

4. No other admixture of any kind will be permitted without written approval from the Contracting Officer’s Representative.

E. Anchorage Items:

1. Inserts for anchoring masonry and mechanical items to concrete, shall be of standard manufacture and of types required to engage with the anchors to be provided and installed therein under other sections of these specifications.

F. Membrane forming curing compound shall be Water - Emulsion Acrylic Curing and Sealing complying with ASTM C 309, Type I, Class B; with a V.O.C. content less than .75 lbs / gal. Membrane shall dry clear. Verify compatibility of material with the Seamless Epoxy Flooring System manufacturer.

1. Acceptable manufacturers shall be one of the following subject to compliance with the specifications:

a. L & M Construction Chemicals, Inc. - “Dress & Seal WB”

b. W.R. Meadows - “VOCOMP - 20"

c. Or Equivalent.

2.2 CONCRETE DESIGN MIX

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2010 by FEI

A. Concrete Design Mix: The concrete mix proportions shall be determined in accordance with the requirements of ACI Standard 318 except as amended herein to produce the strength for each class of concrete with slump, air content, and maximum size of coarse aggregate as specified herein. The concrete design mix shall be the responsibility of the Contractor.

2.3 CLASSES OF CONCRETE AND USAGE

A. Concrete of the various classes indicated and as required in all sections of these specifications or drawings shall be proportioned and mixed for the following requirements:

Class of Concrete and Minimum

Compressive Strength (psi)

Min. bags cement per cubic yard

Max. water-cement ratio

Air Content percent

A4000

0.45

1. Concrete made with high early strength cement shall have a 7 day strength equal to the specified 28 day strength for the concrete of the class specified made with ordinary Portland cement.

B. Usage: Concrete of the various class shall be used as follows:

1. Class A For all cast - in - place concrete work including slabs, grade beams, and all other concrete work indicated in other Sections of this Contract Document.

C. In the field, slump shall be determined in conformance with ASTM Standard C 143, and shall be within the following limits, provided the required strength is obtained.

Structural Element

Slump for Vibrated Concrete, Inches

Minimum

Maximum

Slabs on grade

Other building construction

D. Ready mixed concrete shall conform to ASTM Standard C 94, and the mixing time for mixers over 1 cubic yard capacity shall be increased 15 seconds for each additional 1/2 cubic yard or fraction thereof of material mixed.

PART 3 - EXECUTION

3.1 INSTALLATION OF ANCHORAGE ITEMS

A. Adequate fastening device as required for anchoring masonry, mechanical, and other items to concrete shall be provided and installed at the proper location before concrete is placed. Deviations from this procedure will not be tolerated without prior consent of the Contracting Officer’s Representative. Sufficient time between erection of forms and placing of concrete shall be given to the various trades to permit the proper installation of their work. All anchorage and fastening devices which are provided by the various trades and placed in the forms by the Contractor or by the various trades shall be maintained in position and protected until the concreting is completed.

3.2 PREPARATION FOR PLACING CONCRETE

A. Water shall be removed from excavation before placing concrete. Any flow of water shall be diverted through proper side drains and shall be removed without washing over freshly deposited concrete.

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2010 by FEI

Hardened concrete, debris, and foreign materials shall be removed from interior of forms and from inner surfaces of mixing and conveying equipment. Reinforcement shall be secured in position, and shall be subject to inspection before placing concrete. Runways shall be provided for wheeled concrete handling equipment. Such equipment shall not be wheeled over reinforcement nor shall runways be supported on reinforcement.

3.3 PLACING CONCRETE

A. Concrete shall be handled from mixer to transport vehicle to place of final deposit in a continuous manner, as rapidly as practicable, and without segregation or loss of ingredient until the unit of operation is completed. Concrete will not be placed when the sun, heat, wind, or limitations of facilities furnished by the Contractor prevent proper finishing and curing of the concrete. Concrete shall be placed in the forms, as nearly as practicable in final position, in uniform approximately horizontal layers not over 12 inches deep. Forms or reinforcement splashed with concrete shall be cleaned in advance of placing subsequent lifts. Concrete shall not be allowed to drop freely more than 5 feet in unexposed work nor more than 3 feet in exposed work; where greater drops are required, a tremie or other approved means shall be employed. The discharge of the tremies shall be controlled so that the concrete may be effectively compacted into horizontal layers not more than 12 inches thick, and the spacing of the tremies shall be such that segregation does not occur. Concrete to receive other construction shall be screeded to the proper level to avoid excessive shimming or grouting. Conduits and pipes shall not be embedded in concrete unless specifically indicated.

B. Time Interval Between Mixing And Placing: Concrete mixed and transported by non-agitating equipment shall be placed in the forms within 45 minutes from the time ingredients are charged into the mixing drum. Concrete that is truck mixed or transported in truck mixers or truck agitators shall be delivered to the site of the work and discharge completed in the forms within the time specified in Paragraph 9.7 of ASTM Specification C 94, except that when the concrete temperature exceeds 85 degrees F., the time shall be reduced to 45 minutes. Transit mixed concrete that is completely mixed at the site of concrete placement or batched cement and aggregates transported to mixers shall be placed in the forms within 1 1/2 hours after cement has been added. Concrete shall be placed in the forms within 15 minutes after discharge from the mixer at the job site.

3.4 COMPACTION OF CONCRETE

A. Immediately after placing, each layer of concrete shall be compacted by internal concrete vibrators supplemented by hand spading, rodding and tamping. Tapping or other external vibration of forms will not be permitted. Vibrators shall not be used to transport concrete inside forms. Internal vibrators submerged in concrete shall maintain a speed of not less than 7,000 impulses per minute. The vibrating equipment shall at all times be adequate in number of units and power to properly consolidate all concrete. Spare units shall be on hand as necessary to ensure such adequacy.

Duration of vibration shall be limited to time necessary to produce satisfactory consolidation without causing objectionable segregation. The vibrator shall not be inserted into lower courses that have begun to set. Vibrators shall be applied at uniformly spaced points not farther apart than the visible effectiveness of the machine.

3.5 BONDING AND GROUTING

A. Before depositing new concrete on concrete that has set, the surfaces of the set concrete shall be thoroughly cleaned of laitance, coatings, foreign matter and loose particles. After cleaning concrete surfaces etch the surface with a 1:1 mix of muriatic acid solution and thoroughly rinse with water. Pre -soak all surfaces with water prior to applying the bonding agent. Mortar shall consist of equal parts of Portland cement and fine aggregate by weight and not more than 6 gallons of water/ bonding agent per sack of cement or as required by bonding agent manufacturer.

3.6 SLABS ON GRADE

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A. Concrete shall be compacted, screeded to grade and prepared for the specified finish. Concrete shall be placed continuously so that each unit of operation will be monolithic in construction.

B. Sealing: Concrete contraction joints, where sawed or formed, shall be filled with joint sealing compound.

3.7 CONCRETE SLAB FINISHES

A. General: The ambient temperature of spaces being finished shall be not less than 50 degrees F. The dusting of finish surfaces with dry materials or additions of water to concrete surfaces shall not be permitted.

B. Contractor shall be responsible to pour and finish concrete only when the “window of finishability” can be provided and met.

C. Tolerance for slab flatness and levelness shall be designated by specifying the Face Floor Profile Numbers in accordance with ACI - 117. Floor Flatness Number “FF” controls local surface bumpiness by limiting the magnitude of successive 1 foot slope changes when measured along sample measurement lines in accordance with ASTM E 1155. Floor Levelness Number “FL” controls local conformance to design grade by limiting differences in departures from design grade over distances of 10 feet when measured along sample measurement lines in accordance with ASTM E 1155.

D. Interior concrete slab shall be finished as follows:

1. Immediately after placing and consolidating concrete Contractor shall screed the surface to the desired plane or shape of the predetermined grade/elevation.

2. Upon completion of screeding and before the bleed water migrates to the surface, the concrete surface shall be consolidated and compacted by an initial floating process. Concrete shall be re-straighten as necessary to maintain a flat surface during the finishing process.

3. After the initial floating and re-straightening have been completed, stiffening of the concrete shall be necessary before proceeding with the final finishing process. After the bleed water evaporates additional hand/power floating shall be preformed to prepare meet flatness and levelness requirements. No finishing operation shall be preformed while there is excess moisture or bleed water on the surface of the concrete.

4. Clean surface of all laitance and hand/power float the concrete surface and re-straighten as necessary.

5. The Finish Classification for concrete slab shall be classified as A1 (tile covered, offices, churches, schools, hospitals, ornamental, and garages)" in accordance with ACI 302.1R - 96, with no troweling required. The floor flatness classification shall be “FF - 20" and the floor levelness classification shall be “FL - 15".

3.8 CURING

A. Concrete shall be maintained in a moist condition and shall be protected against rapid temperature change, mechanical injury, and injury from rain or flowing water, for the curing period given below corresponding to the cementing materials used in the concrete.

Type III, cement

3 days

Type I, cement

7 days

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1. Concrete shall be maintained in a moist condition at temperatures above 50 degrees F for the first 7 days or not less than 70 degrees F for the first 3 days and not less than 40 degrees F for the next 4 days, and at a temperature above freezing for the remainder of the specified curing period.

2. Concrete shall be protected from local applications of heat. Concrete shall be protected from rapid temperature change and rapid drying for the first 24 hours following the removal of temperature protection. Curing activities shall be started as soon as free water has disappeared from the surface of the concrete after placing and finishing. Formed undersurfaces of beams, girders, floor slabs and other similar undersurfaces, shall be moist cured with forms in place for the full curing period, or, if forms are removed prior to the end of the curing period, by other approved means.

B. Curing shall be accomplished by any of the following methods or combination thereof, as approved.

1. Moist Curing Option: Unformed surfaces shall be covered with burlap or mats, wetted before placing, and overlapped at least 6 inches. Burlap or mats shall be kept continually wet and in direct contact with the surface. Where formed surfaces are cured in the forms, the forms shall be kept continually wet. If the forms are removed before the end of the curing period, curing shall be continued as on unformed surfaces using suitable materials. Burlap shall be used on surfaces that will be unexposed in the finished work and shall be in two layers.

2. Impervious Sheet Curing Option: All surfaces shall be thoroughly wetted with a fine spray of water and be completely covered with waterproof paper, or polyethylene sheeting, or with polyethylene coated burlap having the burlap thoroughly water saturated before placing.

Covering shall be lapped not less than 12 inches and securely weighted down or shall be lapped not less than 4 inches and taped to form a continuous cover with completely closed joints. Sheets shall be weighted to prevent displacement or billowing from winds. Sheets shall be immediately repaired or replaced if tears or holes appear during the curing period.

3. Membrane Forming Compound Curing Option: Before applying curing compound, tops of joints that are to receive sealer or sealant shall be tightly closed with temporary material to prevent entry of the compound and to prevent moisture loss during the curing period. The compound shall be applied on damp surfaces as soon as the moisture film has disappeared.

The curing compound shall be applied in strict accordance with the manufacturer's recommendations. The compound shall form a uniform, continuous, adherent film that shall not check, crack, or peel, and shall be free from pinholes or other imperfections. Surfaces subjected to heavy rainfall within 3 hours after compound has been applied, or surfaces damaged by subsequent construction operations within the curing period shall be re-sprayed.

Membrane curing compound shall not be used on surfaces that are to receive any subsequent treatment that depends on adhesion or bonding to the concrete except that resin base curing compounds may be used on floors that are to receive adhesive applications of resilient flooring. Membrane curing compound shall not be used on surfaces that are maintained at curing temperatures with free steam. Where membrane forming curing compounds are permitted, permanently exposed surfaces shall be cured by use of a non-pigmented membrane forming curing compound containing a fugitive dye. Where non-pigmented type curing compounds are used, the concrete surface shall be shaded from the direct rays of the sun for the curing period. Surfaces coated with curing compound shall be kept free of foot and vehicular traffic, and from other sources of abrasion and contamination during the curing period.

END OF SECTION

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