02772 Cement Curbs and Gutters Worland Hazmat Building.rtf

Project Name (ftr B) [12/00] 02772 -

CONCRETE CURBS AND GUTTERS

Worland Hazmat Building 02772 -

SECTION 02772

CONCRETE CURBS AND GUTTERS

PART 1: GENERAL

1.1 SUMMARY

A. Section Includes: Construction of curb.

1.2 QUALITY ASSURANCE

PART 2: PRODUCTS

2.1 MATERIALS

A. Concrete: Shall have a 28-day strength of fc=4,500 psi and shall conform to the requirements of Section 03310 - Structural Concrete. The entrained air range shall be 5% to 7%.

B. Reinforcing Steel: Shall conform to the requirements of Section 03310 - Structural Concrete.

C. Isolation Joint Materials: Shall conform to the requirements of Section 03310 - Structural Concrete.

D. Membrane Curing Compound: Shall conform to the requirements of Section 03310 - Structural Concrete.

E. Base Course Material: Shall be sand, gravel, or crushed rock with material passing 1/2‑inch sieve.

F. Plywood: Shall conform to the requirements of Section 03310 - Structural Concrete.

G. Wood Forms: Shall be No. 2 common lumber or better against unexposed concrete surfaces. Wood forms against exposed concrete surfaces shall be dressed and matched boards of uniform thickness and widths not exceeding 10 inches. Plywood conforming to the requirements for formwork as set forth in the American Plywood Association Concrete Forming Guide may be used against both exposed and unexposed concrete surfaces. Plywood shall be at least 9/16-inch thick and have not less than 5 plys.

2.2 SOURCE QUALITY CONTROL

A. Inspection: Forms will be inspected and approved by the Contracting Officer prior to concrete placement. The Contracting Officer will receive one working day notice prior to concrete placement.

B. Testing: The Contractor shall make arrangements for a certified independent testing laboratory, according to the requirements of Section 01458 - Testing Laboratory Services, to perform the required testing, recording, and distributing of the results.

PART 3: EXECUTION

3.1 PREPARATION

A. Earthwork: Excavation and embankment for curbs and gutters shall be as described in the applicable provisions of Section 02322 - Excavation and Fill for Structures. Unsuitable material in the subgrade shall be removed to a specific depth and then backfilled with imported backfill. Payment will not be allowed for excavation below grade and for backfill materials required when such excavation is caused by negligence of the Contractor.

B. Compaction: Subgrade shall be compacted to 95% maximum density according to AASHTO T 99.

C. Grading: Before forms are set, the subgrade shall be graded to within one inch of established grade, and the area between the sidewalk and the adjacent property shall be shaped to line, grade, and section shown on the drawings. Low areas in the subgrade shall be backfilled with imported backfill and compacted.

D. Subgrade Moisture: Dry areas in the subgrade shall be thoroughly dampened prior to placing concrete.

3.2 FORMS

A. General: Forms shall be of wood, metal, or other suitable material and shall extend for the full depth of the concrete. Forms shall be constructed to allow easy removal without prying or hammering against the fresh concrete. Concrete damaged during form removal will be rejected.

C. Bracing: Forms shall be braced to prevent deformation and displacement.

D. Divider Plates: Shall be of metal.

E. Preparation: Wooden forms may be oiled or watered immediately before placement of concrete. Water shall be clean. Water shall not be used when the atmospheric temperature is less than 40 degrees F. Steel forms shall be lightly oiled with a good grade of form oil prior to placing concrete. Excess oil shall be removed.

3.3 PLACING AND FINISHING CONCRETE

A. Placement: Concrete shall be spread uniformly between the forms and thoroughly compacted with a vibrator or other acceptable method.

B. Curb Machine: The curb may be constructed by the use of a curb-forming machine provided it produces the required results. When the curb machine is used, contraction joints may be created in a manner approved by the Contracting Officer.

C. Curb Template: When approved by the Contracting Officer, the exposed curb face may be constructed and finished by use of trowel-type templates, shaped to produce the desired contours when operated along approved forms set to the established lines and grades. When the concrete is green, the top, front, or other exposed surfaces of the curb or combined curb and gutter shall be floated with a moist wood float. Form marks and other irregularities shall be removed.

D. Floating: After compaction and leveling, the concrete shall be floated with wood floats.

E. Edging: Joints shall be edged with a 1/4-inch radius edge.

F. Surface Finishing: The surface shall be brushed with a fiber hairbrush in a transverse direction. For the purpose of matching adjacent concrete finishes or for other reasons, the Contracting Officer may permit other methods of finishing. No plastering will be permitted.

G. Expansion Joints: Shall be placed at intervals of 10 ft, using a preformed expansion joint filler extending the full width of the structure, and have a thickness of 3/4 inch.

I. Curing Compounds: Shall be applied according to Section 03310 - Structural Concrete.

J. Curing Time: Shall be according to Section 03310 - Structural Concrete.

K. Form Removal: Shall be according to Section 03310 - Structural Concrete.

3.4 BACKFILLING

Requirements: After the concrete has set for 14 days, the spaces in front and back of the curb shall be refilled to the required elevation with material similar to adjacent materials which shall be thoroughly tamped, in layers of not more than 6 inches.

3.5 PRECAST CONCRETE CURB

A. Fabrication: Precast concrete curbs may be fabricated by the Contractor at a site off the installation and transported to the installation by the Contractor.

3.6 FIELD QUALITY CONTROL

A. Inspection: Forms will be inspected and approved by the Contracting Officer prior to concrete placement. The Contracting Officer will receive one working day notice prior to concrete placement.

B. Testing: The Contractor shall make arrangements for a certified independent testing laboratory, according to the requirements of Section 01458 - Testing Laboratory Services, to perform the required testing, recording, and distributing of the results.

C. Rejected Concrete Curb: Curbs that are chipped, broken, out of grade or alignment, will be rejected. Replacement curb shall match existing curbing.

3.07 CLEANING

A. Clean-up: Concrete spilled or splashed on adjacent surfaces shall be thoroughly removed. After form removal, backfill and landscape to match surrounding area.

Excess Materials: Excess and waste material shall be disposed of off the site.

PART 4: MEASUREMENT AND PAYMENT

4.1 METHOD OF MEASUREMENT

A. Units: The work described in this section will not be measured for payment.

4.2 BASIS OF PAYMENT

A. Payment: No direct payment for the work described under this section will be made. Consideration for this item shall be included in the bid price for other items of the Contract.

END OF SECTION