A06_-140L1722Q0019-_03306_Concrete_1.pdf

MINOR CONCRETE

Pumphouse ADA Improvements 03/2020

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SECTION 03306

PART 1: GENERAL

1.1 SUMMARY

A. Section Includes: Furnishing and placing cast-in-place concrete, including formwork and reinforcement.

B. Experience: Forming, installing steel reinforcement, placing, and finishing concrete shall be performed with experienced concrete worker(s) whose full time position(s) are involved with the preparation and placement of concrete.

1.2 SUBMITTALS

A. General: Submittals shall be according to Section 01009 - General Information and Requirements.

1.3 QUALITY ASSURANCE

A. General: Forming, installing steel reinforcement as specified, placing, and finishing concrete within the sidewalk, staging area, and parking area.

B. Causes for Rejection: Concrete may be rejected for, but not limited to, the following reasons:

1. Freezing within the first 3 days of placement

2. Excessive or inadequate slump

3. Segregation of aggregate or over-vibration resulting in excessive water in the surface of the concrete

4. Honeycomb over 25% of the surface

5. Voids larger than 2 inches across

6. Exposed reinforcing steel

7. Misalignment of concrete

8. Substandard aggregate in the mix

9. Failure to apply cure/sealer within 24 hour after completion of pour.

PART 2: PRODUCTS

2.1 MATERIALS

A. General: Concrete shall be ready mix as per 2.1 B, onsite mixing of concrete shall not be allowed.

B. Ready Mix Concrete: Ready-mixed concrete shall be according to ASTM C 94 and be designed for a 28-day compressive strength of 4000 psi, and a maximum slump of 4 inches as determined by ASTM C 143.

C. Color-Flatwork Concrete: Shall be “Omaha Tan #5084” as manufactured by

Davis Colors, 3700 Olympic Blvd. Los Angeles, CA 90023, 800-356-4848, www.daviscolors.com, or approved equal.

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D. Concrete Curing Compound: Clear all resin, dissipating water based curing compound, meeting ASTM C-309 requirements. Dayton Superior J11W or approved equal.

E. Reinforcing Steel: Shall have a yield point of 60 ksi and shall be according to grade 60 of ASTM A 615. The size of the bars shall be as indicated on the drawings.

F. Fiber: 100% virgin polypropylene, fibrillated fibers specifically manufactured for use as concrete secondary reinforcement, installed at 1.5 pounds per cubic yard of concrete.

G. Water: Potable water shall be used for mixing concrete.

H. Air-Entraining Admixture: ASTM C260. The amount of air shall be 4 to 6 percent when maximum aggregate size is 3/4-inch, and 4.5 to 7.5 percent when maximum aggregate size is 3/8-inch. A variations of plus or minus 1 percent is allowable.

I. Expansion Joint Material: Preformed filler strips shall be according to

ASTM D 994 and shall be the full width and depth of the joint. Unless otherwise indicated, the material shall be 1/2-inch thick.

J. Joint Sealant: Shall be a two-part polysulfide modified polyurethane sealant, non-staining, able to withstand constant water immersion, and capable of 25% joint movement. Sonolastic Polysulfide Sealant as manufactured by Sonneborn, Division of BASF, 800-433-9517 or www.buildingsystems.basf.com, or approved equal. Submit color sample for approval. Primers and Backer-Rod required with the installation of the sealant shall be as recommended by the manufacturer

PART 3: EXECUTION

3.1 PREPARATION

A. Existing Aggregate Surfacing: In areas where proposed concrete is located over existing aggregate surfacing material, remove, and stockpile the aggregate surfacing material for placement after concrete work is completed.

B. Subbase Preparation: Subbase to be in contact with concrete shall be undisturbed or compacted according to Section 02315 - Excavation and Fill.

C. Form Construction: ACI 347R. Construct forms to the sizes, shapes, lines, and dimensions shown on the drawings. The Contractor shall provide construction aids and imbedded items such as shown on the drawings.

Fabricate forms for easy removal without hammering or prying against the concrete surfaces. Form oil may be applied to facilitate removal of forms.

Forms and subbase shall be wet before placement of concrete.

D. Form Inspection: Notify the Contracting Officer 48 hours in advance of concrete placement to allow for inspection of forming and placement of items

03306 - 3 to be imbedded in the concrete. Excess water shall be removed from the forms before concrete placement.

E. Reinforcing Steel: Shall be held securely in position by steel wire, mortar blocks, or plastic or metal chairs during the placement of concrete.

Workers are not to walk on rebar during placement of the concrete.

Reinforcement shall be inspected by the Contracting Officer before concrete is placed.

F. Expansion Joints: Install expansion joints between existing concrete structures and proposed concrete work and at a maximum of 50’ spacing along the sidewalk. Install so expansion joint material is even with bottom of concrete and approximately 1/4” from top of concrete.

3.2 CONCRETE PLACEMENT

A. Placement and Consolidation: Concrete shall be deposited as nearly as practical to its final position to avoid flow causing segregation of the aggregate. Concrete shall not be dropped more than 5 feet vertically without the use of a tremie or similar device.

B. Concrete Placement under Adverse Conditions: During hot weather, refer to ACI 305R. During cold weather, refer to ACI 306R. Materials required for protection shall be on the jobsite before concrete work is started.

Do not place concrete on a frozen subgrade or against surfaces having deposits of frost, snow, or ice.

3.3 CONCRETE FINISHING

A. Concrete Surface Finishes: Concrete slabs shall be given broom finish.

Brooms shall have a minimum width of 18 inches and shall be applied perpendicular to the centerline. Edges shall be formed with a metal tool to leave a smooth border on the concrete.

B. Form Removal: Formwork not supporting concrete may be removed after curing at not less than 50 degrees F for 24 hours after placing the concrete, and when curing and protection procedures are followed as specified. The concrete should be sufficiently hard so as not to be damaged by form removal.

C. Control Joints: Shall be saw cut, with a wheel mounted saw to a depth of

1/4 of the slab thickness. Saw-cutting control joints shall be completed within 24 hours after finishing concrete, but not until the concrete has cured enough to prevent aggregates from being dislodged by the saw.

Construct control joints within the parling and staging areas as shown on the drawings. Construct control joints within the walkway at a maximum spacing of 8 feet and at the corners of the turnouts as shown on the drawings.

3.4 CONCRETE CURING

A. Concrete Curing Compound: Spray on the concrete curing compound as per manufacturing instructions.

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3.5 PROTECTION

A. Requirements: During the curing period, protect concrete from load stresses, shock loads, or vibration. Do not allow vehicle’s or equipment onto concrete for a minimum of 7 days after completion of the pour.

PART 4: MEASUREMENT AND PAYMENT

4.1 METHOD OF MEASUREMENT

A. Units: The work described in this section will be measured and paid for by the square foot of concrete, based on the dimensions of the parking area, staging area, and trail as shown on the drawings. No extra quantity will be added for concrete placed beyond the lines and grades shown.

Reinforcing steel and bedding material will not be paid for separately, costs associated with these items shall be included within the costs associated for concrete. Flatwork includes sidewalks, staging area, and parking area.

4.2 BASIS OF PAYMENT

A. Prices and payment will be full compensation for the work described in this section. Payment will be made under:

Pay Item Pay Unit

03306(1) L2 Trail . . . . . . . . . . . . . . . . . . . SF

03306(2) L3 Parking and . . . . . . . . . . . . . . . . SF

03306(3) L3 Staging Area . . . . . . . . . . . . . . . SF

END OF SECTION