SECTION 02520

PORTLAND CEMENT CONCRETE PAVING

PART 1 - GENERAL

1.1	RELATED DOCUMENTS

A.	Drawings and general provisions of Contract apply to work of this Section.

1.2	DESCRIPTION OF WORK

A.	Extent of portland cement concrete paving is shown on drawings, including curbs, gutters, walkways and pavement.

B.	Prepared subgrade is specified in "EARTHWORK" section.

C.	Concrete and related materials are specified in Division-3.

D.	Joint fillers and sealers are specified in Division-7.

1.3	QUALITY ASSURANCE

A.	Codes and Standards: Comply with local governing regulations if more stringent than herein specified.

1.4	SUBMITTALS

A.	Furnish samples, manufacturer's product data, test reports, and materials' certifications as required in referenced sections for concrete and joint fillers and sealers.

1.5	JOB CONDITIONS

A.	Traffic Control: Maintain access for vehicular and pedestrian traffic as required for other construction activities.

PART 2 - PRODUCTS

2.1	MATERIALS

A.	Forms: Steel, wood, or other suitable material of size and strength to resist movement during concrete placement and to retain horizontal and vertical alignment until removal. Use straight forms, free of distortion and defects.

1.	Use flexible spring steel forms or laminated boards to form radius bends as required.

2.	Coat forms with a non-staining form release agent that will not discolor or deface surface of concrete.

B.	Welded Wire Mesh: Welded plain cold-drawn steel wire fabric, ASTM A 185.

1.	Furnish in rolls, unless otherwise acceptable to Architect.

C.	Reinforcing Bars: Deformed steel bars, ASTM A 615, Grade 40.

D.	Joint Dowel Bars: Plain steel bars, ASTM A 615, Grade 40. Cut bars true to length with ends square and free of burrs.

E.	Metal Expansion Caps: Furnish for one end of each dowel bar in expansion joints. Design caps with one end closed and a minimum length of 3 inches to allow bars movement of not less than 1 inch, unless otherwise indicated.

F.	Hook Bolts: ASTM A 307, Grade A bolts, internally and externally threaded. Design hook bolt joint assembly to hold coupling against pavement form and in position during concreting operations, and to permit removal without damage to concrete or hook bolt.

G.	Concrete Materials: Comply with requirements of applicable Division-3 sections for concrete materials, admixtures, bonding materials, curing materials, and others as required.

H.	Expansion Joint Materials: Comply with requirements of applicable Division-7 sections for preformed expansion joint fillers and sealers.

I.	Anti-Spalling Compound: 50% (by volume) boiled linseed oil and 50% (by volume) mineral spirits, complying with AASHTO M-233.

J.	Liquid-Membrane Forming Curing Compound: Complying with ASTM C 309, Type I, Class A unless other type acceptable to Architect. Moisture loss not more than 0.055 gr./sq. cm. when applied at 200 sq. ft./gal.

1.	Available Products: Subject to compliance with requirements, products which may be incorporated in the work include, but are not limited to, the following:

"Masterseal"; Master Builders.

"A-H 3 Way Sealer"; Anti-Hydro Waterproofing Co.

"Ecocure"; Euclid Chemical Co.

"Clear Seal"; A.C. Horn.

"J-20 Acrylic Cure"; Dayton Superior.

"Sure Cure"; Kaufman Products Inc.

"Spartan-Cote"; The Burke Co.

"Sealkure"; Toch Div. - Carboline.

"Kure-N-Seal"; Sonneborn-Contech.

"Polyclear"; Upco Chemical/USM Corp.

"L&M Cure"; L & M Construction Chemicals.

"Klearseal"; Setcon Industries.

"LR-152"; Protex Industries.

"Hardtop"; Gifford - Hill.

K.	Bonding Compound: Polyvinyl acetate or acrylic base, rewettable type.

1.	Available Products: Subject to compliance with requirements, products which may be incorporated in the work include, but are not limited to, the following:

"J-40 Bonding Agent"; Dayton Superior Corp.

"Weldcrete"; Larsen Products.

"Everbond"; L & M Construction Chemicals.

"EucoWeld"; Euclid Chemical Co.

"Hornweld"; A. C. Horn.

"Sonocrete"; Sonneborn-Contech.

"Acrylic Bondcrete"; The Burke Co.

L.	Epoxy Adhesive: ASTM C 881, two component materials suitable for use on dry or damp surfaces. Provide material "Type," "Grade," and "Class" to suit project requirements.

1.	Available Products: Subject to compliance with requirements, products which may be incorporated in the work include, but are not limited to, the following:

"Epoxtite"; A. C. Horn.

"Edoco 2118 Epoxy Adhesive"; Edoco Technical Prod.

"Sikadur Hi-Mod"; Sika Chemical Corp.

"Euco Epoxy 463 or 615"; Euclid Chemical Co.

"Patch and Bond Epoxy"; The Burke Co.

"Sure-Poxy"; Kaufman Products Inc.

2.2	CONCRETE MIX, DESIGN AND TESTING

A.	Comply with requirements of applicable Division-3 sections for concrete mix design, sampling and testing, and quality control, and as herein specified.

Design mix to product normal-weight concrete consisting of portland cement, aggregate, water-reducing of high-range water-reducing admixture (super-plasticizer), air-entraining admixture and water to produce the following properties:

1.	Compressive Strength: 3000 psi, minimum at 28 days, unless otherwise indicated.

2.	Slump Range: 8 inches for concrete containing HRWR admixture (super- plasticizer); 3 inches for other concrete.

3.	Air Content: 5% to 8%.

PART 3 - EXECUTION

3.1	SURFACE PREPARATION

A.	Remove loose material from compacted subgrade surface immediately before placing concrete.

Proof-roll prepared subbase surface to check for unstable areas and need for additional compaction. Do not begin paving work until such conditions have been corrected and are ready to receive paving.

3.2	FORM CONSTRUCTION

A.	Set forms to required grades and lines, rigidly braced and secured. Install sufficient quantity of forms to allow continuous progress of work and so that forms can remain in place at least 12 hours after concrete placement.

Check completed formwork for grade and alignment to following tolerances:

1.	Top of forms not more than 1/8 inch in 10 feet.

2.	Vertical face on longitudinal axis, not more than 1/4 inch in 10 feet.

Clean forms after each use, and coat with form release agent as often as required to ensure separation from concrete without damage.

3.3	REINFORCEMENT

A.	Locate, place and support reinforcement as specified in Division-3 sections, unless otherwise indicated.

3.4	CONCRETE PLACEMENT

A.	General: Comply with requirements of Division-3 sections for mixing and placing concrete, and as herein specified.

1.	Do not place concrete until subbase and forms have been checked for line and grade. Moisten subbase if required to provide a uniform dampened condition at time concrete is placed. Do not place concrete around manholes or other structures until they are at required finish elevation and alignment.

2.	Place concrete using methods which prevent segregation of mix. Consolidate concrete along face of forms and adjacent to transverse joints with internal vibrator. Keep vibrator away from joint assemblies, reinforcement, or side forms. Use only square-faced shovels for hand-spreading and consolidation. Consolidate with care to prevent dislocation of reinforcing, dowels, and joint devices.

Deposit and spread concrete in a continuous operation between transverse joints, as far as possible. If interrupted for more than 1/2-hour, place a construction joint.

3.	Fabricated Bar Mats: Keep mats clean and free from excessive rust, and handle units to keep them flat and free of distortions. Straighten bends, kinks, or other irregularities or replace units as required before placement. Set mats for a minimum 2 inches overlap to adjacent mats.

Place concrete in 2 operations; strike-off initial pour for entire width of placement and to the required depth below finish surface. Lay fabricated bar mats immediately in final position. Place top layer of concrete, strike-off and screed.

a.	Remove and replace portions of bottom layer of concrete which has been placed more than 15 minutes without being covered by top layer or use bonding agent if acceptable to Architect.

3.5	JOINTS

A.	General: Construct expansion, weakened-plane (contraction), and construction joints true-to-line with face perpendicular to surface of concrete. Construct transverse joints at right angles to the centerline, unless otherwise indicated.

When joining existing structures, place transverse joints to align with previously placed joints, unless otherwise indicated.

1.	Weakened-Plane (Contraction) Joints: Provide weakened-plane (contraction) joints, sectioning concrete into areas as shown on drawings. Construct weakened-plane joints for a depth equal to at least 1/4 concrete thickness, as follows:

a.	Tooled Joints: Form weakened-plane joints in fresh concrete by grooving top portion with a recommended cutting tool and finishing edges with a jointer.

2.	Construction Joints: Place construction joints at end of placements and at locations where placement operations are stopped for a period of more than 1/2-hour, except where such placements terminate at expansion joints.

a.	Construct joints as shown or, if not shown, use standard wood or metal keyway-section forms.

b.	Where load transfer-slip dowel devices are used, install so that one end of each dowel bar is free to move.

3.	Expansion Joints: Provide premolded joint filler for expansion joints abutting concrete curbs, catch basins, manholes, inlets, structures, walks and other fixed objects, unless otherwise indicated.

Locate expansion joints at spacings indicated.

Extend joint fillers full-width and depth of joint, and not less than 1/2 inch or more than 1 inch below finished surface where joint sealer is indicated. If no joint sealer, place top of joint filler flush with finished concrete surface.

Furnish joint fillers in one-piece lengths for full width being placed, wherever possible. Where more than one length is required, lace or clip joint filler sections together.

Protect top edge of joint filler during concrete placement with a metal cap or other temporary material. Remove protection after concrete has been placed on both sides of joint.

4.	Fillers and Sealants: Comply with the requirements of applicable Division-7 sections for preparation of joints, materials, installation, and performance.

3.6	CONCRETE FINISHING

A.	After striking-off and consolidating concrete, smooth surface by screeding and floating. Use hand method only where mechanical floating is not possible. Adjust floating to compact surface and produce uniform texture.

After floating, test surface for trueness with a 10' straightedge. Distribute concrete as required to remove surface irregularities, and refloat repaired areas to provide a continuous smooth finish.

Work edges of slabs, gutters, back top edge of curb, and formed joints with an edging tool, and round to 1/2 inch radius, unless otherwise indicated. Eliminate tool marks on concrete surface.

After completion of floating and troweling when excess moisture or surface sheen has disappeared, complete surface finishing, as follows:

1.	Broom finish, by drawing a fine-hair broom across concrete surface, perpendicular to line of traffic. Repeat operation if required to provide a fine line texture acceptable to Architect.

2.	On inclined slab surfaces, provide a coarse, non-slip finish by scoring surface with a stiff-bristled broom, perpendicular to line of traffic.

Do not remove forms for 12 hours after concrete has been placed. After form removal, clean ends of joints and point-up any minor honeycombed areas. Remove and replace areas or sections with major defects, as directed by Architect.

3.7	CURING

A.	Protect and cure finished concrete paving, complying with applicable requirements of Division-3 sections. Use membrane- forming curing and sealing compound or approved moist-curing methods.

3.8	REPAIRS AND PROTECTIONS

A.	Repair or replace broken or defective concrete, as directed by Architect.

B.	Drill test cores where directed by Architect, when necessary to determine magnitude of cracks or defective areas. Fill drilled core holes in satisfactory pavement areas with portland cement concrete bonded to pavement with epoxy adhesive.

C.	Protect concrete from damage until acceptance of work. Exclude traffic from pavement for at least 14 days after placement. When construction traffic is permitted, maintain pavement as clean as possible by removing surface stains and spillage of materials as they occur.

Sweep concrete pavement and wash free of stains, discolorations, dirt and other foreign material just prior to final inspection.

END OF SECTION