CONCRETE_SPECS.pdf

SECTION 03100 CONCRETE

PART 1 - GENERAL

SUMMARY

This section covers non-structural concrete cement finish work, including cast-in-place concrete, concrete reinforcement, and concrete accessories used for cast-in-place concrete.

Non-Structural Concrete: thrust blocks, concrete patches, sidewalk, curb and gutter and small concrete pads.

REFERENCES

ASTM A82 – Standard Specification for Cold Drawn Steel Wire, Plain, for Concrete Reinforcement

ASTM A185 – Standard Specification for Steel Welded Wire Reinforcement, Plain, for Concrete

ASTM A496 – Standard Specification for Steel Wire, Deformed, for Concrete Reinforcement

ASTM A615 – Standard Specification for Deformed and Plain Carbon-Steel Bars for Concrete Reinforcement

ASTM A706 – Standard Specification for Low-Alloy Steel Deformed and Plain Bars for Concrete Reinforcement

ASTM A775 – Standard Specification for Epoxy-Coated Steel Reinforcing Bars

ASTM C31 – Standard Practice for Making and Curing Concrete Test Specimens in the Field

ASTM C33 – Standard Specification for Concrete Aggregates

ASTM C94 – Standard Specification for Ready Mixed Concrete

ASTM C143 – Standard Test Method for Slump of Portland Cement Concrete

ASTM C150 – Standard Specification for Portland Cement

ASTM C233 – Standard Test Method for Air-Entraining Admixtures for Concrete

ASTM C260 – Standard Specification for Air-Entraining Admixtures for Concrete

ASTM C309 – Standard Specification for Liquid Membrane-Forming Compounds for Curing Concrete

ASTM C494 – Standard Specification for Chemical Admixtures for Concrete

SUBMITTALS

One copy with each bid

Ready Mix supplier

a. Name of supplier

b. Location of ready mix plant

c. Route from plant to construction site

d. Delivery time

Reinforcing steel test certificates of manufacturer’s laboratory, identifying chemical and physical analysis of each load of reinforcing steel.

Concrete Mix Design

All submittals shall represent materials used in proposed mix design.

Mixed proportions Aggregate sieve analysis Source of aggregate and mixing water used Type and brand of cement Results of all tests required to show that the proposed mix and materials are in compliance with the specifications.

a. Test materials in accordance with ASTM C143, ASTM C192, and ASTM

C231

b. Design the mix in accordance with ACI 613

Delivery tickets for each load of concrete delivered to the site and other information as specified under ASTM C94.

QUALITY ASSURANCE

The Contractor shall comply with all requirements of the codes and standards mentioned in Section 1.2 “References”, as applicable.

Obtain cement and aggregate from the same source for all work.

FIELD QUALITY CONTROL

Contractor is responsible for demonstrating compressive strength of concrete actually used in the completion of the work.

The laboratory shall test job specimens in accordance with applicable ASTM Standards, and perform other tests requested by the Owner.

Non-Structural Concrete: Testing: Not Required

PART 2 - PRODUCTS

CONCRETE MATERIALS

Cement:

All cement used in concrete work shall be Portland Cement Type II, conforming to all requirements of the “Standard Specifications for Portland Cement” (ASTM C150)

Total alkali content less than 0.6%, expressed as Na2O equivalent.

Storage:

a. Store in suitable, dry, weatherproof buildings on floors raised above the ground, or in weather-tight, moisture and damp proof bins. No cement shall be used which has become caked or lumpy.

Aggregates:

Fine Aggregates:

a. Natural sand, composed of clean, hard, durable, uncoated, well rounded grains, preferably of siliceous materials.

b. Conform to “Standard Specification for Concrete Aggregates” (ASTM C33) except as follows:

1) Deleterious substances shall not be in excess of: (by weight)

a) Clay lumps 0.25%

b) Material finer than #200 sieve 2%

c) Coal and Lignite 0.25%

d) Other deleterious materials 0.25%

2) Aggregates shall have approved service records of at least 3 years.

3) Aggregates shall show loss of weight no greater than 8% after 5 cycles of sodium sulphate soundness testing.

4) Manufactured sand may be used in place of natural sand with the written approval of the Owner provided the test of the material for organic impurities (ASTM C40) does not show the color darker than standard.

5) Free from injurious amounts of alkali and organic impurities.

c. Well graded from coarse to fine according to ASTM C33 to the below sieve analysis gradation:

SIEVE SIZE

PERCENT PASSING

3/8-inch

No. 4

95-100

No. 16 50-85

No. 50

10-30

No. 100

2-10

d. Store materials in such a manner as to prevent deterioration or intrusion of foreign matter.

C. Mixing Water:

Clean and free from injurious amounts of mud, oil, acid, alkali, organic matter or other deleterious substances, and shall produce concrete strengths at least 95% of that of similar specimens made with water approved by the Owner.

Non-potable water may be used if mortar cubes made with the mixing water in question have 7-day and 28-day strength equal to at least 95% of the companion specimen in which potable water was used.

D. Admixtures:

Water Reducing:

a. Conform to ASTM C494, Type A, and be used in strict accordance with the manufacturer’s recommendations.

b. Possess approved service record of not less than 5 years.

Air Entraining:

a. Conform to ASTM C260, and be used in strict accordance with the manufacturer’s recommendation. Provide technical assistance of the manufacturer’s field representative upon request of the Owner.

b. Air entrained in the following amount:

1) 1½-inch to 2-inch maximum size aggregate: 4-6%

2) ¾-inch to 1-inch maximum size aggregate: 5-7%

Other Admixtures may be necessary and may be used upon written approval from of the Owner.

E. Concrete Mix:

Non-Structural Concrete:

a. Ultimate strength of 3,000 psi at 7 days and 4,000 psi at 28 days, and contain a minimum of 6 sacks of cement per cubic yard of concrete.

b. Testing will not be required.

F. Reinforcement Steel:

1. Bars:

c. Conform to the requirements of the Standard Specification for deformed

Billet-Steel Bars for Concrete Reinforcement with 60,000 psi Minimum Yield Strengths ASTM A615 “Standard Specification for Deformed and Plain Carbon-Steel Bars for Concrete Reinforcement”.

d. Epoxy coated reinforcement steel bars shall conform to the requirements of ASTM A775 “Standard Specification for Epoxy-Coat

2. Wire Mesh Fabric:

a. Conform to the requirements of ASTM A185 “Standard Specification for Steel

Welded Wire Reinforcement, Plain, for Concrete”.

3. Bolsters, Chairs, and Accessories:

a. Provision for all spacers, bolsters, bar chairs, ties and other devices necessary to properly space, place, support and fasten reinforcements shall be made by the Contractor and as approved of by the Owner.

2.2 Placing Concrete

A. Initial Requirements

1. Place in accordance with ACI Code 318.

2. Clean all bonding surfaces, free of laitance and foreign materials before deposit concrete.

3. Place concrete on a properly prepared and unfrozen sub-grade and only in a dewatered excavation or forms.

4. The Contractor will not be allowed to deposit concrete which is partially hardened or has been contaminated with foreign materials.

5. The Contractor will not allow entrance of mud or foreign materials into the concrete during placement operations.

6. Notify COR a minimum of 24 hours in advance of concrete placement.

Part 3 - EXECUTION

3.1 PLACEMENT OF REINFORCEMENT

A. Place in accordance with ACI 318, Chapter 7. Fabricate all reinforcement steel with cold bends conforming to the recommended dimensions shown in ACI 318.

Field fabrication will be allowed only if the Contractor has equipment to properly fabricate steel and is approved in writing by the Owner.

Thoroughly clean all reinforcing steel of mill and rust scale and of coatings that will destroy or reduce the bond.

Carefully form steel to the dimensions indicated on the plans. Do not bend or straighten in a manner that will injure the materials. Use of bars with kinks or bends is not allowed.

Accurately place and secure against displacement by using annealed wire of not less than No. 18 gauge, or suitable clips at intersections and where necessary by metal chairs or spacers or metal hangers.

Splicing of reinforcing bars at points of maximum stress is not allowed.

Make all joints or splices by using approved clamps, welding or by lapping the ends of the bars a distance of at least 40 times their nominal diameters unless otherwise noted on the plans.

Place in the position and at the spacings shown on the plans. The minimum cover for reinforcing steel is as follows:

Location of Reinforcing Steel Bars

Minimum Cover

Bottom bars on soil bearing foundations 3 inches

Bar adjacent to surfaces to exposed to weather saturated air in tanks, earth backfill, or water

2 inches

For bars more than 5/8-inch in diameter 1 ½ inches

Bars in other locations, not less than diameter of bar

¾ inches

3.2 CONCRETE CONSISTENCY

A. Maintain a uniform consistency for each class of work and verify by means of slump tests.

B. The slump for vibrated or tamped concrete: 1½ inches and not more than 3 inches.

C. Slump for when hand puddling is permitted without vibration or tamping: not less than 3 inches or more than 6 inches.

D. Vary the consistency of the concrete as directed by the Contract Representative.

E. If, through accident, intention or error in mixing, any concrete is too wet, such concrete shall not be incorporated in the work, but shall be discarded as waste material.

3.3 FINISH OF FORMED SURFACES

A. Smooth Form Finish (trowel finish):

This finish includes formed concrete surfaces which will be exposed to the air in the completed structure or to be covered with a coating material applied directly to the concrete, or a covering material bonded to the concrete, such as water proofing, damp-proofing, painting, or other similar system.

A smooth form finish provides a smooth, hard, uniform texture and arranging them orderly and symmetrically with a minimum of seams.

Patch all defective areas and repair with all fins or other projections completely removed and smoothed.

For smooth form finish walls:

a. Fill snap-tie holes with approved non-shrink, nonmetallic color matched grout.

b. Grind off projections, fins, and rough spots.

c. Repair other defects such as honeycomb areas, rock pockets, and rough spots resulting from form release agent failure or other reason with color matched non-shrink grout.

For smooth form trowel finish slabs:

a. Finish by screeding and floating with straightedges to bring surface to required finish elevation shown.

b. While concrete is still green, but sufficiently hardened to bear a person's weight without deep imprint, wood float to true, even plane with no coarse aggregate visible.

c. Use sufficient pressure on wood floats to bring moisture to surface.

d. After surface moisture has disappeared, hand trowel concrete to produce smooth, impervious surface, free from trowel marks.

e. Burnish surface with an additional troweling. Final troweling shall produce a ringing sound from trowel.

f. Do not use dry cement or additional water during troweling. No excessive troweling will be permitted.

g. Power finishing:

1) An approved power machine may be used in lieu of hand finishing for finishing concrete floors and slabs in accordance with directions of machine manufacturer.

2) Do not use power machine when concrete has not attained the necessary set to allow finishing without introducing high and low spots in slab.

3) Do first steel troweling for slab by hand.

B. Broomed Finish:

1. Finish all exposed horizontal surfaces as specified for trowel floor finish, except omit final troweling and finish surface by drawing a fine-hair broom lightly across the surface.

2. Brooming shall be completed in same direction and parallel to expansion joints, or, in the case of inclined slabs, perpendicular to slope.

C. Edging

1. All exposed edges of mortar topped surfaces shall be finished with an edging tool having an edge radius not to exceed 3/8 inch.

3.4 DEFECTIVE CONCRETE

A. Defective concrete is defined as concrete in place, which does not conform to the strength, shapes, alignments, appearances and/or elevation, as shown on the drawings and/or presents faulty surface areas.

B. Concrete surfaces not finished or cured in accordance with specifications are classified as defective concrete.

C. Defective concrete shall be removed and replaced at no additional cost.

D. Formed surfaces larger or smaller than the specified dimensional tolerances shall be deemed defective concrete. If the Owner permits the Contractor to correct the error, such correction shall be as directed and in such a manner as to maintain the strength, function, and appearance of the structure.

F. Inaccurately formed surfaces exposed to view may be rejected and shall be repaired or removed and replaced and no additional cost.

END OF SECTION