BAFBRWHQ 03050.pdf

SECTION 03050 REPAIR WING HEADQUARTERS, BLDG 706

CONCRETE, FORMS, AND REINFORCEMENT CRWU 06-2071

06/09/09 03050-1 BUCKLEY AFB

SECTION 03050 - CONCRETE, FORMS, AND REINFORCEMENT

PART 1 - GENERAL

1.01 SUMMARY:

A. This Section includes concrete, forms, and steel reinforcement.

1.02 REFERENCES:

A. Applicable Standards:

1. American Concrete Institute (ACI):

a. 304R - Guide for Measuring, Mixing, Transporting, and Placing Concrete.

b. 305R - Hot-Weather Concreting.

c. 306R - Cold-Weather Concreting.

d. 318 - Building Code Requirements for Structural Concrete.

e. SP-66 - Detailing Manual.

2. American Society for Testing and Materials (ASTM):

a. A82 - Steel Wire, Plain, for Concrete Reinforcement.

b. A185 - Steel Welded Wire Fabric, Plain, for Concrete Reinforcement.

c. A615 - Deformed and Plain Billet-Steel Bars for Concrete Reinforcement.

d. C31 - Practice for Making and Curing Concrete Test Specimens in the Field.

e. C33 - Concrete Aggregates.

f. C39 - Test Method for Compressive Strength of Cylindrical Concrete Specimens.

g. C94 - Ready-Mixed Concrete.

h. C143 - Test Method for Slump of Hydraulic Cement Concrete.

i. C150 - Portland Cement.

j. C172 - Practice for Sampling Freshly Mixed Concrete.

k. C192 - Practice of Making and Curing Concrete Test Specimens in the Laboratory.

l. C309 - Liquid Membrane-Forming Compounds for Curing Concrete.

m. C494 - Chemical Admixtures for Concrete.

n. C881 - Epoxy-Resin-Base Bonding Systems for Concrete.

o. C1315 - Liquid Membrane-Forming Compounds Having Special Properties for

Curing and Sealing Concrete.

3. Concrete Reinforcing Steel Institute (CRSI):

a. Manual of Standard Practice.

1.03 SUBMITTALS:

A. Submit as specified in DIVISION 1.

B. Include, but not limited to, the following:

1. Complete reinforcing-bar schedule, reinforcing-bar details, and erection drawings to conform to ACI SP-66.

2. Each type of reinforcing bar marked with identification corresponding to identification tag on bar.

3. Erection drawings clear, easily legible, and to a minimum scale of:

a. 1/4 inch = 1 foot.

b. 1/8 inch = 1 foot if bars in each face are shown in separate views.

4. Size and location of all openings.

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5. Grade of steel.

6. Lap lengths.

C. Concrete Mix:

1. Submit proposed concrete-mix proportions for approval prior to placing concrete. Mix proportions shall be selected preferably on the basis of field experience.

2. Submit fine- and coarse-aggregate gradation data for approval prior to placing concrete.

1.04 QUALITY ASSURANCE:

A. Field Testing: Shall be performed by an ACI Concrete Field Testing Technician Grade 1.

PART 2 - PRODUCTS

2.01 CONCRETE MATERIALS:

A. Cement: Conform to ASTM C150. Portland cement Type I or I/II.

B. Water: Clean and free from injurious amounts of oil, acids, alkalies, or other deleterious substances. Any potable drinking water will be acceptable.

C. Fine Aggregates: Clean natural sand. Manufactured sand may be used upon written approval of Engineer. Conform to ASTM C33.

D. Coarse Aggregates: Clean crushed stone or processed gravel, not containing organic materials. Conform to ASTM C33, size No. 57.

E. Air Entrainment: Conform to ASTM C260.

F. Water-Reducing Admixture: Conform to ASTM C494, Type A.

G. Admixtures shall not contain chloride ions.

2.02 CONCRETE MIX PROPORTIONS:

A. 4,000 psi (with the following proportions and limitations:).

1. Minimum Compressive Strength: 4,000 psi at 28 days.

2. Slump: 3 inches, +1 inch.

3. Air Content: 6% +1.5%.

B. Ready-Mixed Concrete:

1. Concrete shall meet requirements of ASTM C94 and of materials and proportions specified.

2. Ready-mixed concrete plant shall be subject to approval of Engineer.

2.03 FORMS:

A. Form Materials:

1. Use one of the following:

a. Exterior Grade Plywood: 5/8-inch-thick (use only plywood or steel for all exposed concrete Work).

b. Steel.

c. Approved wood fiberboard.

d. Dressed lumber free of loose knots.

2. Form Ties:

a. Break-back, coil, or screw-type, except where otherwise specified.

b. Use water-seal coil type in walls below grade and in walls of water-bearing structures.

3. Chamfer Strips:

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a. 3/4-inch chamfer except where otherwise indicated.

b. Place in all forms to provide chamfer where concrete will have exposed projecting corners.

2.04 CONCRETE REINFORCEMENT:

A. Reinforcement Bars: Conform to ASTM A615, Grade 60 for all bars No. 4 or larger.

B. Tie, and all No. 3 Bars: Conform to ASTM A615, Grade 40.

C. Bolsters, Chairs, and Accessories: Conform to ACI SP-66 and CRSI Manual of Standard

Practice.

2.05 BONDING AGENT:

A. Provide moisture-insensitive, epoxy-resin bonding agent conforming to ASTM C881, Type V.

2.06 CONCRETE ACCESSORIES:

2.07 CURING AGENT:

A. Apply to all concrete surfaces unless otherwise indicated or specified.

B. Curing agent shall conform as follows:

1. ASTM C309, Type 1: Use where concrete surface is not exposed to direct sunlight after placement.

2. ASTM C309, Type 1-D: Use where slabs are exposed to direct sunlight for a period of seven days minimum after placement. Curing and sealing agent with fugitive dye shall be readily distinguishable upon the concrete surface for at least four hours after application but shall be inconspicuous within seven days after application.

3. ASTM C309, Type 2: Use as specified in PART 3, ARTICLE 3.05 - HOT WEATHER CONCRETING, this Section.

C. Curing compound used on floors to be sealed, painted, tiled, topped, dampproofed, waterproofed, or covered with resilient floor covering shall be guaranteed not to interfere with application of sealer, paint, tile mortar, or tile adhesive after a 28-day curing period.

D. Curing compound shall be VOC compliant with a maximum VOC content of 2.9 lbs/gal (350 g/L), or less where Project location regulations are more stringent.

PART 3 - EXECUTION

3.01 FIELD TESTING:

A. Field Testing of Concrete and Making of Concrete Test Cylinders:

1. Contractor shall furnish test equipment, test cylinder molds, and certified personnel to perform all required field tests, make the required concrete test cylinders, and deliver test cylinders to the testing laboratory. The prescribed tests shall be made in the presence of or with the concurrence of Owner.

2. Test concrete and make test cylinders conforming to ASTM C31, C143, and C172.

Samples shall be taken at random and at the point of truck discharge.

3. Perform slump and air content tests throughout any placement as required to maintain constant quality of fresh concrete, and when directed by Engineer.

4. Field testing personnel shall remain on Site throughout placement of concrete.

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5. Make not less than four test cylinders for each 100 cubic yards of concrete or fraction thereof for each day concrete is placed. Deliver to testing laboratory within 24 hours after taking cylinders. Exercise care not to damage cylinders in transit.

B. Laboratory Testing:

1. An independent testing laboratory will be selected and paid by the Owner to perform the required laboratory tests.

2. Laboratory will cure concrete cylinders conforming to ASTM C192.

3. Cylinders shall be tested conforming to ASTM C39. Average strength of two cylinders

(same age) shall be used as result of the test. Break two cylinders at 7 days(, two at 14 days) and two at 28 days.

3.02 LOW-STRENGTH CONCRETE:

A. Defined as concrete whose 7-day (and 14-day test) (average of two cylinders) is less than 70%

(and 85% respectively) of the specified minimum 28-day compressive strength.

B. Disposition of Concrete:

1. Concrete shall remain accessible with no other Work performed that relates to or depends upon the questionable concrete until a final decision as to the disposition of the concrete is given by Engineer.

2. Low-strength concrete shall be removed and replaced if so requested by Engineer.

3.03 PLACING OF CONCRETE:

A. Preparation:

1. Clean bonding surfaces free from laitance and foreign materials.

2. Verify that all embedded items are accurately and securely installed.

3. Place concrete on properly prepared and unfrozen subgrade and only in dewatered excavations.

4. Do not deposit partially hardened concrete or concrete contaminated by foreign materials.

B. Placing Concrete:

1. Conform to ACI 304R.

2. Place within 45 minutes after mixing, except Engineer may extend the period to 90 minutes (maximum) dependent upon weather conditions.

3. Place in horizontal layers not exceeding 18 inches.

4. Vibrate or spade concrete to produce solid mass without honeycomb or surface air bubbles.

C. Curing Concrete:

1. Cure with curing agent. Apply according to manufacturer's recommendations.

2. Apply curing compound to all exposed surfaces immediately after removing form or after finishing concrete.

3. Keep formwork wet until stripped.

D. Cold-Weather Placing: Conform to the practice recommended in ACI 306R when the temperature is below 40oF or is likely to fall below 40oF during 24-hour period after placing.

E. Hot-Weather Placing: Conform to practices recommended in ACI 305R when temperature is 90oF or above or is likely to rise above 90oF within 24-hour period after placing, or when there is a combination of high air temperature, low relative humidity, and wind velocity which would impair either concrete strength or quality.

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3.04 CONSTRUCTION JOINTS:

A. Locate where indicated. Conform to ACI 318.

B. Clean and break laitance or other foreign material from bonding surface. Bed with 1 inch of grout for bonding in horizontal joints.

3.05 SURFACE FINISHES:

A. Float Finish:

1. Compact, accurately screed, and wood-float all slabs to a true uniform surface.

2. Test surface with straightedge, and eliminate high and low spots of more than 1/8 inch in

10 feet.

3. Use this finish in addition to the finishes specified below for all surfaces as indicated.

4. Use as final finish for footing slabs not exposed.

B. Hard-Troweled Finish:

1. Finish surface as in "Float Finish" and in addition, trowel with steel trowel to obtain a smooth dense finish after concrete has hardened to ring under the trowel.

2. Use this finish on all floors, slabs, and equipment bases not specifically designated for a different finish.

C. Broom Finish:

1. Finish surface as in "Float Finish" and, in addition, draw a stiff bristled broom across the previously floated surface.

2. Corrugations shall be uniform in appearance, not more than 1/16 inch in depth, and shall be perpendicular to direction of traffic.

3. Use this finish on all outdoor slabs subject to vehicular or pedestrian traffic.

D. Burlap Finish:

1. Apply burlap surface treatment to exposed edges of slabs, curbs, and foundations.

2. Wet and fill all voids using mortar with the same sand-cement ratio as original concrete.

Use approximately 20% white cement to match concrete color.

3. 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.

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 PART 3 - PLACING OF CONCRETE, this Section.

E. Defective Surface Treatments:

1. After removal of forms, remove all fins, projections, and form ties.

2. Grout and cure all voids, damaged areas, and tie holes.

3.06 FORMS:

A. Treat forms with commercially available form releasing agents that will not bond with, stain, or adversely affect concrete surfaces. Agents shall not impair subsequent treatment of concrete surfaces depending upon bond or adhesion, nor shall it impede the wetting of surfaces to be cured with water or curing compounds. Form releasing agents shall be VOC compliant with a maximum VOC content of 3.8 lbs/gal (450 g/L), or less where area restrictions are more stringent.

B. Wet forms with clean, clear water prior to placing concrete.

C. Adequately brace and stiffen forms to prevent deflection and settlement.

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3.07 STEEL REINFORCEMENT:

A. Place all steel reinforcement before concrete is cast in accordance with approved erection drawings, ACI 117, Chapters 7 and 12 of ACI 318, and the CRSI Manual of Standard Practice.

B. Tie securely with 16-gage or larger annealed iron wire.

C. Splice steel reinforcement where indicated. Unless otherwise indicated, the minimum length of lap for tension lap splices shall be as required for Class B splices as defined by ACI 318.

D. Lap welded wire fabric not less than the length of one mesh.

3.08 REPAIR, REPLACEMENT, AND FIELD MODIFICATIONS:

A. Embedded items and concrete that are misplaced or damaged during construction shall not be repaired, replaced, or field-modified without approval of Engineer.

END OF SECTION 03050