Specification3301-Revised.pdf

CAST-IN-PLACE CONCRETE – 03301 1

DIVISION 3 - CONCRETE

03301 – CAST-IN-PLACE CONCRETE

PART 1 - GENERAL

1.1 - Description

This section specifies concrete to be used for cast-in-place concrete construction.

1.2 - Related Work Specified Elsewhere

02220 - Excavation, Embankment and Backfill for Buildings 02512 - Concrete Slab 13120 – Pump House Building

1.3 - Submittals

(a) Mix Design: A mix design showing the proposed weights of aggregate, water, cement and other components per cubic yard of concrete shall be furnished to the Engineer a minimum of 72 hours prior to the placement of concrete. No concrete shall be placed without prior approval of this mix design.

(b) Admixtures: Complete information on proposed admixtures, as specified herein, shall be submitted for the Engineer's approval a minimum of 72 hours prior to the placement of concrete.

(c) Deliver Tickets: Provide Engineer with a delivery ticket in accordance with ASTM C-94 for each load of concrete.

PART 2 - PRODUCTS

2.1 - Cement

Type I or Type II portland cement unless otherwise specified - ASTM C-150. Only one brand of cement shall be used.

2.2 - Aggregate

Aggregate shall meet the requirements of ASTM C 33, "Specifications for Concrete Aggregate".

Coarse aggregate shall be Size Number 67 as specified therein.

2.3 - Admixtures for Concrete

(a) Air Entrainment: Air-entraining admixtures shall meet the requirements of ASTM C-260.

(b) Water Reducers: Water-reducing, set-retarding, and set-accelerating admixtures shall meet the requirements of ASTM C-494.

(c) Submittals: Furnish the following information to the Engineer for approval:

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1. Brand name of the admixture.

2. Amount of admixture to be used per cubic yard of concrete.

3. Reason for requesting the use of the admixture.

2.4 - Curing Materials

Curing materials shall meet the following requirements:

(a) Burlap cloth made from jute or kenaf. . . . . . . . . . . . AASHTO M-182

(b) Sheet materials for curing concrete . . . . . . . . . . . . . ASTM C-171

(c) Membrane-forming curing compounds . . . . . . . . . . ASTM C-309, Type 1 or 1-D

2.5 - Water

Potable water shall be used for mixing, curing, or other applications.

2.6 - Joint Filler

(a) Poured Filler: Poured filler for joints shall meet the requirements of ASTM D 1190.

(b) Preformed Filler: Preformed filler for joints shall meet the requirements of ASTM D 994, ASTM

D 1751, or ASTM D 1752 and shall be punched to admit dowels as necessary. The filler for each joint shall be furnished in a single piece according to the depth and width required for the joint.

When the use of more than one piece is authorized for a joint, the abutting ends shall be fastened securely and held in position by stapling or other positive fastening approved by the Engineer.

2.7 - Proportioning Concrete

Minimum compressive strength of concrete shall be 3000 psi. Proportion concrete within the limits below:

Minimum Cement Content 5.5 sacks/cubic yard Maximum Water Content 6 gallons/sack Entrained Air 3 to 6 per cent Slump 1 to 4 inches

2.8 - Proportioning Concrete for Cold Weather

For concrete placed under "Cold Weather Concreting and Curing" conditions, the Contractor may elect to alter the required proportions in one of the following ways:

Type III Cement: Type III cement may be substituted in equal quantities for Type I or II cement.

Additional Cement: An additional sack per cubic yard of Type I or Type II cement may be added.

2.9 - Temperature Limits for Cold Weather Concrete

Provide concrete having a minimum temperature of 50 degrees F and a maximum temperature of 90 degrees F at the time of placing. The temperature of the mixing water shall not exceed 140 degrees F.

If aggregates are heated, heat uniformly with steam or water coil. Aggregate temperature shall not

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exceed 95 degrees F. Aggregate water mix temperature shall not exceed 80 degrees F. Do not use materials containing frost or icy lumps.

2.10 - Temperature Limits for Hot Weather Concrete

Provide concrete having a maximum temperature of 90 degrees F at time of placing. If the ambient temperature is above 90 degrees F, the forms, reinforcing steel, steel beam flanges, and other surfaces which will come in contact with the mix shall be cooled to below 90 degrees F by means of a water spray or other approved methods. Water reducing admixtures shall be used so the maximum amount of water or slump is not exceeded. The mixing of the concrete and the time between mixing and placing shall be kept to a minimum. Chipped or crushed ice may be substituted for a portion of the mixing water on a pound-for-pound basis. If ice is used, all ice shall be entirely melted at the completion of the mixing period. If concrete temperature exceeds 75 degrees F, concrete shall be in accordance with

ACI 305.

2.11 - Mixing

(a) Plant Batched and Transit Mixed:

1. Batch at a central plant and mix en route to the project in transit mix trucks in compliance with

ASTM C-94. (ASTM C 94 Sections 3 and 17 shall not apply).

2. Place concrete within a maximum of 1-1/2 hours after introduction of cement into the batch. In hot weather or due to other contributing factors, a time less than 1-1/2 hours may be required by the Engineer.

3. Time interval between placement of batches shall not exceed 30 minutes.

(b) Portable Mixer or Hand Mixed:

Onsite and hand mixing of concrete will be allowed for small operations such as concrete slab for the new pumphouse building.

2.12 - Mix Adjustments

(a) Water: Water may be added once for purposes of acquiring minimum slump, provided the specified water-cement ratio is not exceeded. For all project-mixed concrete, water shall not be added later than 15 minutes from start of mixing. For transit-mixed or agitated concrete, such water may be added upon arrival at the job site. Adding water beyond these conditions constitutes retempering which will not be allowed. When water is added, an additional 20 revolutions at mixing speed is required.

(b) Admixtures: Air-entraining admixtures shall not be added after the start of mixing.

PART 3 - EXECUTION

3.1 - Construction

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(a) Excavation: Excavation shall be made to the required dimensions to permit the installation and bracing of the forms. The foundation shall be compacted to a firm even surface. All soft, yielding material shall be removed and replaced with acceptable material.

(b) Forms: Forms shall meet the requirements of Specification 03100 - Concrete Formwork.

Machine slip forming may be used.

(c) Contraction Joints: Sections shall be separated by open joints approximately 1/8-inch wide and at least 1-inch deep, except at expansion joints. Where the curb is constructed adjacent to concrete pavement, the contraction or open joints in the curb shall match the contraction joints in the pavement.

(d) Expansion Joints: Expansion joints shall be formed at the intervals SHOWN ON THE

DRAWINGS using a preformed expansion joint filler having a thickness of 1/2 inch. When the curb is constructed adjacent to or on concrete pavement, expansion joints shall be located at expansion joints in the pavement.

(e) Mixing and Placing: The concrete shall be struck off to the cross section SHOWN ON THE

DRAWINGS, after which it shall be finished to a smooth and even surface.

(f) Reinforcement: All reinforcing steel shall be placed in position SHOWN ON THE

DRAWINGS and securely held in place by approved supports during placing of concrete.

Concrete shall not be placed until the grading, forms, and steel reinforcements have been inspected and approved by the Engineer. The Contractor shall give the Engineer 24 hours notice prior to placement of any concrete.

(g) Placement: Concrete shall be discharged into the forms within 1-1/2 hours after the introduction of the cement to the aggregate. Retempering concrete shall not be permitted. The cement shall be added to the mixer at the jobsite whenever this condition cannot be met.

(h) Temperature: Concrete shall not be mixed or placed when the daily minimum atmospheric temperature is, or is expected to be, less than 40 degrees F unless adequate provisions are made to protect the concrete. No concrete shall be placed when the concrete temperature reaches 90 degrees F.

(i) Consolidation: Concrete shall be placed to avoid segregation. High-frequency internal vibrators shall be used for consolidating concrete in the forms. Vibrators shall be operated to produce concrete free of voids, but shall not be held so long in one place as to result in segregation or formation of laitance on the surface.

(j) Handling: The use of aluminum pipe, conduit, or troughs for transporting concrete will not be permitted. When concrete is pumped, sampling shall be from the discharge stream at the point of placement.

(k) Finishing: For the purpose of matching adjacent concrete finishes or for other reasons, the

Engineer may permit other methods of finishing than those specified. No plastering will be permitted.

(l) Concrete Placement: Notify the Engineer a minimum of 24 hours prior to placement.

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Place concrete in the forms as near final position as practical in a manner which will prevent segregation or loss of materials.

Place concrete in maximum 18" horizontal layers.

Immediately after placing, thoroughly compact concrete with mechanical vibrators. Provide minimum of two vibrators. Provide minimum of two power sources unless commercial power is available at site. Hand-tamping, when permitted, will be approved in writing by the Engineer.

Place each concrete section in a continuous operation, such as slab, footing, columns.

Do not drop concrete freely more than 4 feet.

Do not place concrete in water or allow water to rise over freshly placed concrete until a set is sufficient to prevent damage.

(m) Backfilling: After the concrete has set sufficiently, it shall be backfilled to the required elevation with selected material placed in horizontal layers, not over 6 inches (loose measure) in depth, to the level of the original ground surface. Backfill shall be readily compactible material free of frozen lumps, chunks of highly plastic clay, or other objectionable material.

Rocks larger than 3 inches in diameter shall not be used within 1 foot of the structure.

(n) Protection from Rainfall: Protect flat work during rainy periods with adequate waterproof covering. Support covering so that finishing may be performed and initial set obtained without damage. Dragging of tarpaulins or other covering across unset concrete will not be permitted.

(o) Curing: Commence curing and protection of concrete immediately after completion of the finishing. Cure Type I and Type II cement for 7 days continuously, cure Type III cement for 3 days continuously. The work shall be moistened and kept moist during this time, or curing shall be accomplished by the use of membrane-forming curing compound.

(p) Cold Weather Concreting and Curing When the descending air temperature at the project falls below 40 degrees F the Contractor shall cease placing concrete unless the procedures described below are followed. Normal concreting operations may resume when the ascending temperature at the site exceeds 40 degrees F.

Provide cover and heating equipment sufficient to maintain the temperature of the concrete at not less than 50 degrees F for a period of period of 3 days for Type I and Type II cement. Maintain the temperature at not less than 50 degrees F for a period of 2 days for Type III cement or when one additional sack of Type I or Type II cement is added.

Provide additional protection to prevent the concrete temperature from dropping more than 40 degrees F in the 24-hour period following the required protection period.

Keep concrete and forms wet. Remove and replace any concrete damaged by frost or freezing when directed by the Engineer.

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(q) Hot Weather Concreting and Curing: If curing temperatures as placed are expected to exceed

75 degrees F, placing and curing shall be in accordance with ACI 305.

PART 4 - MEASUREMENT AND PAYMENT

4.1 - Measurement

The work specified herein will not be measured for payment.

4.2 - Payment

This work is considered incidental to other items in the contract and direct separate payment will not be made.

END OF SPECIFICATION 03301

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