27-02506 Concrete Curb.pdf

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SECTION 02506

CONCRETE CURB AND CURB WALLS

PART 1 GENERAL

1.1 WORK INCLUDED

A. Contractor shall furnish all materials, implements, machinery equipment, tools, supplies, transportation, labor and supervision required to construct curved or straight concrete curbing of the size indicated, at the locations shown on the plan or as directed by the Engineer.

1.2 RELATED WORK SPECIFIED ELSEWHERE

A. Concrete Sidewalk and ADA Ramps - Section 02507

1.3 REFERENCE STANDARDS

A. Pennsylvania Department of Transportation (PennDOT) Publication 408, Specifications, latest edition.

1.4 SUBMITTALS

A. Material Certificates: Provide copies of material certificates signed by material producer and Contractor, certifying that each material item complies with, or exceeds, specified requirements.

PART 2 PRODUCTS

2.1 MATERIALS

A. Plain cement concrete curb and curb walls shall conform to PennDOT Form 408, Section 630, and PennDOT design drawings RC-64M and RC-67M.

B. Concrete:

1. Shall be air entrained (6%), 3,750 p.s.i. PennDOT Class AA concrete in accordance with Section 704 of PennDOT Specifications, Publication 408, latest edition.

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B. Premolded Expansion Joint Filler:

1. Shall be 3/4-inch thick fiber expansion joint filler.

C. Curing Materials:

1. Shall be white polyethylene sheeting, burlap, or clear or white liquid membrane - forming curing compound in accordance with PennDOT

Specifications, Publication 408, latest edition.

PART 3 EXECUTION

3.1 SUBGRADE PREPARATION

A. The curb area shall be excavated to the proposed subgrade line, the excavation shall include the removal of existing paving and curbing, if necessary, and the disposal of all excess material.

B. The subgrade line shall be eighteen (18”) inches below and parallel to the top of finished curbing. Any areas which are over-excavated shall be filled with PennDOT

2A stone at the Contractor's expense.

C. When directed, remove and replace unsuitable material with acceptable material.

3.2 FORMWORK

A. Metal forms shall be staked securely to the established lines and grades. Wood forms are acceptable on sharp curves and for closure sections.

B. Forms shall be cleaned and oiled prior to each use, without causing a discoloration of the concrete. Forms shall not be removed until such time as it will not be detrimental to the concrete. Upon removal of the forms minor defects shall be filled with mortar.

C. As soon as possible after the removal of the forms, backfill the voids adjacent to the curb, using acceptable material.

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3.3 JOINTS

A. Expansion joints, using 3/4-inch thick expansion joint material, cut to the cross-sectional area of the curb, shall be located at structures, changes of grade, ends of sections of curved curbing, cold joints and elsewhere at intervals not exceeding 50 feet.

B. Contraction joints, 3/16-inch wide and 2-inches deep shall be formed or sawed at intervals not exceeding ten (10’) feet.

C. All joints shall be neatly edged with a ¼-inch radius edging tool.

3.4 PLACING AND FINISHING CONCRETE

A. In accordance with PaDOT Specifications, Publication 408, latest edition.

B. Carbon copies of all concrete delivery slips, indicating quantity and mix design, shall be given to the Engineer, daily, for each delivery.

C. Concrete shall be placed in the forms in layers not exceeding 6 inches in depth and shall be spaded or vibrated sufficiently to eliminate voids.

D. As indicated or directed provide drainage openings through the curb, at the elevation and of the size required.

E. As indicated or directed, place depressed curb for drives or ramps for the handicapped.

F. Finish the top surface of the curb smoothly and evenly using a wood float, using an edging tool round the edges of the face and back of curb as indicated.

3.5 PROTECTION AND CURING

A. Curb shall be protected and cured for a period of not less than seventy-two (72) hours after completion.

B. If polyethylene sheets of burlap are used for curing they shall be properly weighted down and the concrete shall be kept moist through the curing period.

C. Concrete curb shall not be placed when the air temperature is below 40F unless approved precautions are taken to prevent freezing.

3.6 ACCEPTANCE

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A. All defects found shall be repaired or replaced by the Contractor, at his expense, to the full satisfaction of the Engineer prior to acceptance.

END OF SECTION