Attachment_6_-_SECTION_321600_PAVEMENT_AND_WALKS.doc

SECTION 32 16 00

PAVEMENT AND WALKS

PART 1 - GENERAL

1.1

SECTION INCLUDES

A. This section covers aggregate base course, bituminous (asphalt) pavements, and concrete walks.

1.2 RELATED WORK

A. Section 03 33 00 B. Section 31 10 01

C. Section 31 23 33

1.3 QUALITY STANDARDS

A. Manufacturer Qualifications: A paving-mix manufacturer registered with and approved by authorities having jurisdiction or the Colorado DOT.

B. Regulatory Requirements: Comply with materials, workmanship, and other applicable requirements of the Colorado DOT for asphalt paving work.

C. AASHTO M17, M140, M147, M208, M226, T89, T90, T96, T180.

1.4 SUBMITTALS

A. In accordance with Section 01 33 23.

B. Product data for each type of product.

C. Material certificates for each paving material.

D. Testing reports

PART 2 - PRODUCTS

2.1 AGGREGATES AND BITUMINOUS PAVEMENT

A. AGGREGATES

1. Aggregate base shall meet the grading requirements of Class 6 Aggregate for Bases, as specified in the Colorado Department of Transportation Standard Specifications for Road and Bridge Construction Coarse Aggregate, or approved equal.

150mm (6")

100mm (4")

75mm (3")

95-100

37.5mm (1.5")

25mm (1")

19mm (3/4")

50-90

95-100

2.36mm (#8)

NOTE: Class 3 material shall consist of bank or pit run material.

2. Fine Aggregate: ASTM D 1073 or AASHTO M 29, sharp-edged natural sand or sand prepared from stone, gravel, cured blast-furnace slag, or combinations thereof.

3. Mineral Filler: ASTM D 242/D 242M or AASHTO M 17, rock or slag dust, hydraulic cement, or other inert material.

B. ASPHALT MATERIALS

1. Asphalt Binder: Bituminous material for binder shall meet the requirements of CDOT Standard Specifications for Road and Bridge Construction, or approved equal.

2. Tack Coat: Bituminous material tack coat to meet the requirements of CDOT Standard Specifications for Road and Bridge Construction, or approved equal.

3. Prime Coat: Emulsion for prime coat to meet the requirements of CDOT Standard Specifications for Road and Bridge Construction, or approved equal.

C. AUXILIARY MATERIALS

1. Recycled Materials for Hot-Mix Asphalt Mixes: Reclaimed asphalt pavement; reclaimed, unbound-aggregate base material; and recycled tires, asphalt shingles, or glass from sources and gradations that have performed satisfactorily in previous installations, equal to performance of required hot-mix asphalt paving produced from all new materials.

D. MIXES

1. Hot-Mix Asphalt: Dense-graded, hot-laid, hot-mix asphalt plant mixes shall meet the requirements of CDOT Standard Specifications for Road and Bridge Construction and complying with the following requirements:

a. Provide mixes with a history of satisfactory performance in geographical area where Project is located.

b. Base Course: not to exceed 4-inch thickness.

c. Surface Course: Not to exceed 4-inch thickness but no less than 1.5-inch thickness.

2.2 CONCRETE WALKS

A. Concrete Mix Design and Placement: See Section 03 33 00.

PART 3 - EXECUTION

3.1

GENERAL

A. Drives and walks shall be constructed to the lines, grades, and cross sections indicated on Drawings. Type of construction shall be as indicated on the Drawings and as specified herein.

B. Preparation of Subgrade: Subgrade shall be thoroughly compacted and properly shaped before any surfacing materials are placed. No concrete or hot bituminous pavement shall be placed on subgrade that is frozen, muddy, or has frost or water thereon.

C. No surfacing shall be started until all excavation backfill within the designated roadway, trail, or other paved areas is complete, including backfill and compaction to the existing grade or required subgrade.

D. Base surface shall be approved by the Contracting Officer or their representative prior to applying asphalt. At all times, ditches and drains along the roadbed shall be cleaned and maintained to drain effectively.

E. In no case shall any surfacing material be placed on a frozen, muddy, or unstable subgrade, or until the subgrade has been checked and approved by the Contracting Officer or their representative.

3.2 ASPHALT PATCHING

Retain this article if patching existing pavement. Retain "Asphalt Pavement" Paragraph below if existing pavement is asphalt.

A. Asphalt Pavement: Saw cut perimeter of patch and excavate existing pavement section to sound base. Excavate rectangular or trapezoidal patches, extending 12 inches into perimeter of adjacent sound pavement, unless otherwise indicated. Cut excavation faces vertically. Remove excavated material. Recompact existing unbound-aggregate base course to form new subgrade.

Retain "Portland Cement Concrete Pavement" Paragraph below if existing pavement is portland cement concrete.

Retain "Tack Coat" Paragraph below for coating vertical surfaces abutting hot-mix asphalt patches.

B. Tack Coat: Before placing patch material, apply tack coat uniformly to vertical asphalt surfaces abutting the patch. Apply at a rate of 0.05 to 0.15 gal./sq. yd..

1. Allow tack coat to cure undisturbed before applying hot-mix asphalt paving.

2. Avoid smearing or staining adjoining surfaces, appurtenances, and surroundings. Remove spillages and clean affected surfaces.

Retain "Placing Patch Material" Paragraph below for asphalt or concrete pavement. A single asphalt course is preferred by AI.

C. Placing Patch Material: Fill excavated pavement areas with hot-mix asphalt base mix for full thickness of patch and, while still hot, compact flush with adjacent surface.

3.3 PERMANENT PAVEMENT REPLACEMENT

A. The permanent and final repaving of all drives and similar surfaces where pavement has been removed, disturbed, settled, or damaged by, or as a result of, performance of the Contract shall be repaired and replaced by the Contractor in accordance with Section 32 16 00. The permanent asphalt shall be replaced with bituminous materials of the same depth and kind as the existing unless otherwise specified.

B. The top surface shall conform with the grade of existing adjacent pavement and the entire replacement shall be in accordance with Section 32 16 00.

C. When scheduled and within the time specified, the temporary pavement shall be removed and a base prepared at the depth required by the Contracting Officer to receive the permanent pavement.

1. The base shall be brought to the required grade and cross-section and thoroughly compacted before placing the permanent pavement.

2. Any base material which has become unstable for any reason shall be removed and replaced with compacted materials.

D. Prior to placing the permanent pavement all service boxes, manhole frames and covers, and similar structures within the area shall be adjusted to the established grade and cross-section.

E. The edges of existing asphalt pavement shall be cut a minimum of one foot beyond the excavation of disturbed base.

1. All cuts shall be parallel or perpendicular to the centerline of the street.

F. Prior to placing of any bituminous pavement, a sealer shall be applied to the edges of the existing pavement and other features.

G. The furnishing, handling, and compaction of all bituminous materials shall be in accordance with Section 32 16 00.

3.3 ASPHALT SURFACE PREPARATION

A. General: Immediately before placing asphalt materials, remove loose and deleterious material from substrate surfaces. Ensure that prepared subgrade is ready to receive paving.

B. Saw cut existing edge of pavement to provide a clean, smooth surface for joint between existing and new pavement.

Retain first paragraph below for full-depth asphalt pavement.

C. Proof-roll subgrade below pavements with heavy pneumatic-tired equipment to identify soft pockets and areas of excess yielding. Do not proof-roll wet or saturated subgrades.

Retain "Herbicide Treatment" Paragraph below if weed control is required.

Retain "Tack Coat" Paragraph below if tack coating an existing hot-mix asphalt pavement before placing a hot-mix asphalt overlay.

D. Tack Coat: Apply uniformly to surfaces of existing pavement at a rate of 0.05 to 0.15 gal./sq. yd.

1. Allow tack coat to cure undisturbed before applying hot-mix asphalt paving.

2. Avoid smearing or staining adjoining surfaces, appurtenances, and surroundings. Remove spillages and clean affected surfaces.

3.4 PLACING HOT-MIX ASPHALT

Retain this article for new paving and hot-mix asphalt overlay on existing asphalt or concrete pavements.

A. Machine place hot-mix asphalt on prepared surface, spread uniformly, and strike off. Place asphalt mix by hand in areas inaccessible to equipment in a manner that prevents segregation of mix. Place each course to required grade, cross section, and thickness when compacted.

Revise first subparagraph below to higher temperature if thin lifts in cool weather are likely. See National Asphalt Pavement Association recommendations.

1. Spread mix at a minimum temperature of 250 deg F.

2. Regulate paver machine speed to obtain smooth, continuous surface free of pulls and tears in asphalt-paving mat.

B. Place paving in consecutive strips not less than 10 feet wide unless infill edge strips of a lesser width are required.

C. Promptly correct surface irregularities in paving course behind paver. Use suitable hand tools to remove excess material forming high spots. Fill depressions with hot-mix asphalt to prevent segregation of mix; use suitable hand tools to smooth surface.

3.5 ASPHALT JOINTS

A. Construct joints to ensure a continuous bond between adjoining paving sections. Construct joints free of depressions, with same texture and smoothness as other sections of hot-mix asphalt course.

1. Complete Surface Preparation (above) and clean contact surfaces and apply tack coat to joints.

2. Offset longitudinal joints, in successive courses, a minimum of 6 inches.

3. Offset transverse joints, in successive courses, a minimum of 24 inches.

4. Construct transverse joints at each point where paver ends a day's work and resumes work at a subsequent time. Construct these joints using either "bulkhead" or "papered" method according to AI MS-22, for both "Ending a Lane" and "Resumption of Paving Operations."

3.6 ASPHALT COMPACTION

A. General: Begin compaction as soon as placed hot-mix paving will bear roller weight without excessive displacement. Compact hot-mix paving with hot, hand tampers or with vibratory-plate compactors in areas inaccessible to rollers.

1. Complete compaction before mix temperature cools to 185 deg F.

B. Breakdown Rolling: Complete breakdown or initial rolling immediately after rolling joints and outside edge. Examine surface immediately after breakdown rolling for indicated crown, grade, and smoothness. Correct laydown and rolling operations to comply with requirements.

C. Intermediate Rolling: Begin intermediate rolling immediately after breakdown rolling while hot-mix asphalt is still hot enough to achieve specified density. Continue rolling until hot-mix asphalt course has been uniformly compacted to the following density:

Revise average density and range of acceptable densities in "Average Density" Subparagraph below if required. Subparagraph refers to Rice test method preferred by AI.

1. Average Density: 92 percent of reference maximum theoretical density according to ASTM D 2041, but not less than 90 percent or greater than 96 percent.

D. Finish Rolling: Finish roll paved surfaces to remove roller marks while hot-mix asphalt is still warm.

E. Edge Shaping: While surface is being compacted and finished, trim edges of pavement to proper alignment. Bevel edges while asphalt is still hot; compact thoroughly.

F. Protection: After final rolling, do not permit vehicular traffic on pavement until it has cooled and hardened.

G. Erect barricades to protect paving from traffic until mixture has cooled enough not to become marked.

3.7 INSTALLATION TOLERANCES

A. Asphalt Pavement Thickness: Compact each course to produce the thickness indicated within the following tolerances:

Retain thickness tolerances in "Base Course" and "Surface Course" subparagraphs below or revise to suit Project.

1. Base Course: Plus or minus 1/2 inch.

2. Surface Course: Plus 1/4 inch, no minus.

B. Asphalt Pavement Surface Smoothness: Compact each course to produce a surface smoothness within the following tolerances as determined by using a 10-foot straightedge applied transversely or longitudinally to paved areas:

Revise "Base Course" or "Surface Course" Subparagraph below to suit Project.

1. Base Course: 1/4 inch.

2. Surface Course: 1/8 inch.

Retain "Crowned Surfaces" Subparagraph below if required.

3. Crowned Surfaces: Test with crowned template centered and at right angle to crown. Maximum allowable variance from template is 1/4 inch.

3.8 FIELD QUALITY CONTROL

Retain "Testing Agency" Paragraph below to identify who shall perform tests and inspections.

A. Testing Agency: Contractor will engage a qualified testing agency to perform tests and inspections.

B. Replace and compact hot-mix asphalt if core tests are taken.

C. Remove and replace or install additional hot-mix asphalt where test results or measurements indicate that it does not comply with specified requirements.

3.9 WASTE HANDLING

Retain this article if repairs, patching, or cold milling of existing pavement is required.

A. General: Except for material to be recycled, remove excavated materials from Project site and debris, and legally dispose of them off Government's property and as specified in Section 017419 “Construction Waste Management and Disposal.”

3.10 CONCRETE WALKS

A. Concrete walks shall be constructed at the locations indicated on the Drawings. See Section 03 33 00.

B. Compact each layer of subgrade to a minimum of 95 percent of modified proctor density (ASTM-D1557).

C. Concrete walks shall be of the width and thickness indicated on the Drawings and shall be reinforced as shown on the Drawings.

D. Construction joints shall be formed at intervals equal to the width of the sidewalk and on distances indicated in Section 03 33 00.

E. Concrete shall be struck off true to cross section as indicated on the Drawings, after which it shall be floated smooth and even by means of a wooden float.

F. Immediately after the water sheen has disappeared from the sidewalk surface, said surface shall be given a light broom finish at right angles to the centerline.

G. No work shall be performed on the concrete during the time water sheen is present.

END OF SECTION 32 16 00

DINO 257302A

32 16 00 - 2

PAVEMENT AND WALKS