addendum_00002_32_11_13_A.C._Pavement_and_Base__(REVISED_7-28-2017_Rev2).pdf

ASPHALT CONCRETE PAVEMENT AND BASE 321113 - 1

SECTION 321113 – ASPHALT CONCRETE PAVEMENT AND BASE

PART 1 -- GENERAL

1.1 SUMMARY

A. The Contractor shall provide asphalt concrete pavement and base, complete and in place, in accordance with the Contract Documents.

1.2 REFERENCE SPECIFICATIONS, CODES, AND STANDARDS

A. The following is a list of standards that may be referenced in this section:

1. Colorado Department of Transportation (CDOT): Standard

Specifications for Road and Bridge Construction (2011) (latest revisions).

2. American Association of State Highway and Transportation Officials

(AASHTO):

a. M17, Standard Specification for Mineral Filler for Bituminous

Paving Mixtures.

b. M81, Standard Specification for Cut-Back Asphalt (Rapid Curing Type).

c. M82, Standard Specification for Cut-Back Asphalt (Medium

Curing Type).

d. M140, Standard Specification for Emulsified Asphalt.

e. M208, Standard Specification for Cationic Emulsified Asphalt.

f. T166, Standard Method of Test for Bulk Specific Gravity of

Compacted Asphalt Mixtures Using Saturated Surface-Dry Specimens.

g. T176 Standard Method of Test for Plastic Fines in Graded Aggregates and Soils by Use of the Sand Equivalent Test.

h. T230, Standard Method of Test for Determining Degree of Pavement Compaction of Bituminous Aggregate Mixtures.

i. T245, Standard Method of Test for Resistance to Plastic Flow of Bituminous Mixtures Using Marshall Apparatus.

j. T246, Standard Method of Test for Resistance to Deformation and Cohesion of Bituminous Mixtures by Means of Hveem Apparatus.

k. T247, Standard Method of Test for Preparation of Test Specimens of Bituminous Mixtures by Means of California Kneading Compactor.

l. T283, Standard Method of Test for Resistance of Compacted Bituminous Mixture to Moisture Induced Damage.

m. T304, Standard Method of Test for Uncompacted Void Content of Fine Aggregate (Method A).

3. Asphalt Institute (AI):

a. Manual Series No. 2 (MS-2), Mix Design Methods for Asphalt

Concrete.

b. Superpave Series No. 2 (SP-2), Superpave Mix Design.

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4. ASTM International (ASTM):

a. D2041, Test Method for Theoretical Maximum Specific Gravity and

Density of Bituminous Paving Mixtures.

b. D4318, Test Methods for Liquid Limit, Plastic Limit, and

Plasticity Index of Soils.

c. D4791, Test Method for Flat Particles, Elongated Particles, or Flat and

Elongated Particles in Coarse Aggregate.

d. D5821, Test Method for Determining the Percentage of Fractured

Particles in Coarse Aggregate.

e. E329, Specification for Agencies Engaged in the Testing and/or

Inspection of Materials Used in Construction.

1.3 DEFINITIONS

A. Combined Aggregate: Mineral constituents of asphalt concrete mix, including mineral filler and separately sized aggregates.

B. RAP: Reclaimed asphalt pavement.

C. Standard Specifications: CDOT Standard Specifications for Road and Bridge Construction (2011) (latest revisions).

1.4 DESIGN REQUIREMENTS

A. Prepare hot-mix asphalt concrete mix design, meeting the following design criteria, tolerances, and other requirements of this Specification and the CDOT Standard Specifications, Section 401.

1.5 SUBMITTALS

A. Submittals shall be in accordance with Section 013300 - Contractor Submittals. Include materials testing reports, job-mix formulas, and other pertinent information satisfactory to the Contracting Officer.

1. Asphalt Concrete Mix Formula:

a. Submit minimum of 15 days prior to start of production.

b. Submittal to include the following information:

1) Gradation and portion for each aggregate constituent used in mixture to produce a single gradation of aggregate within specified limits.

2) Bulk specific gravity for each aggregate constituent.

3) Measured maximum specific gravity of mix at optimum asphalt content determined in accordance with

ASTM D2041.

4) Properties as stated in Sections 411 and 702 of the CDOT Standard Specifications, for at least four different asphalt contents other than optimum, two below optimum, and two above optimum.

5) Percent of asphalt lost due to absorption by aggregate.

6) Index of Retained Strength (TSR) at optimum asphalt

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content as determined by AASHTO T283.

7) Percentage of asphalt cement, to nearest 0.1 percent, to be added to mixture.

8) Optimum mixing temperature.

9) Optimum compaction temperature.

10) Temperature-viscosity curve of asphalt cement to be used.

11) Brand name of any additive to be used and percentage added to mixture.

2. Test Report for Asphalt Cement:

a. Submit minimum 10 days prior to start of production.

b. Show appropriate test method(s) for each material and the test results.

3. Manufacturer’s Certificate of Compliance for the following materials:

a. Aggregate: Gradation, source test results as defined in Sections 703 of the CDOT Standard Specifications.

b. Asphalt for Binder: Type, grade, and viscosity-temperature curve.

c. Prime Coat: Type and grade of asphalt.

d. Tack Coat: Type and grade of asphalt.

e. Additives.

f. Mix: Conforms to job-mix formula.

4. Test Results:

a. Mix design.

b. Asphalt concrete core.

c. Gradation and asphalt content of uncompacted mix.

d. Field density.

5. Test Laboratory: Submit the name and qualifications of test laboratory, including inspection personnel qualifications, for approval. Submit copies of current laboratory and personnel certifications.

1.6 QUALITY ASSURANCE

A. Qualifications:

1. Independent Testing Laboratory: In accordance with ASTM E329.

2. Prepare asphalt concrete mix formula by approved certified independent laboratory under the supervision of a certified asphalt technician.

1.7 ENVIRONMENTAL REQUIREMENTS

A. Temperature: Asphalt shall be placed only when the following temperature requirements are met:

1. Tack Coat: Minimum surface temperature of 60 degrees F.

2. Asphalt Base Course: Minimum surface temperature of 40 degrees F and rising at time of placement.

3. Asphalt Surface Course: Minimum surface temperature of 60 degrees F at time of placement.

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B. Moisture: Do not apply asphalt materials or place asphalt mixes when application surface is wet or excessively damp or when rain is imminent.

PART 2 -- PRODUCTS

2.1 ASPHALT CONCRETE MIX

A. General:

1. Do not modify mix formula except with written approval of

Contracting Officer.

2. Source Changes:

a. Should material source(s) change, establish new asphalt concrete mix formula before new material(s) is used.

b. Perform check tests of properties of plant-mix bituminous materials on first day of production and as requested by Contracting Officer to confirm that properties are in compliance with design criteria.

c. Make adjustments in gradation or asphalt content as necessary to meet design criteria.

B. Composition: Dense, hot-laid, hot mix asphalt plant mixes approved by authorities having jurisdiction and complying with the following requirements:

1. Provide mixes with a history of satisfactory performance in the Denver metropolitan area.

2. Base Course: PG 64-22

3. Surface Course: PG 76-28

C. Aggregate: Shall conform to CDOT Standard Specifications for Road and Bridge Construction (2011) (latest revisions), Grade SX.

D. Mineral Filler: ASTM D 242, rock or slag dust, hydraulic cement, or other inert material.

E. Asphalt Binder: AASHTO M 320 or AASHTO MP 1a, PG 76-28. Asphalt Binder shall meet requirements in CDOT Standard Specifications, Section 702.01.

F. Tack Coat: Emulsified asphalt, conform to Sections 411 and 702 of the CDOT Standard Specifications. Emulsified asphalt shall be slow setting, diluted in water, and of suitable grade and consistency for application.

PART 3 -- EXECUTION

3.1 GENERAL

A. Traffic Control: Minimize inconvenience to traffic, but keep vehicles off freshly treated or paved surfaces to avoid pickup and tracking of asphalt.

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B. Weather Limitations: Place hot mix asphalt only on properly prepared unfrozen surfaces that are free of water, snow, and ice in accordance with CDOT Standard Specifications, Section 401.06.

3.2 LINE AND GRADE

A. Provide and maintain intermediate control of line and grade, independent of underlying base, to meet finish surface grades and minimum thickness.

B. Shoulders: Construct to line, grade, and cross-section shown.

3.3 EXAMINATION

A. 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.

B. Proceed with paving only after unsatisfactory conditions have been corrected.

3.4 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. Herbicide Treatment: Apply herbicide according to manufacturer’s recommended rates and written application instructions. Apply to dry, prepared subgrade or surface of compacted-aggregate base before applying paving materials.

C. 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.

D. Existing Roadway:

1. Modify profile by grinding, milling, or overlay methods as approved, to meet lines and surfaces and to produce smooth riding connection to existing facility.

2. Remove existing material to a minimum depth of 1 inch.

3. Paint edges of meet line with tack coat prior to placing new pavement.

E. Thoroughly coat edges of contact surfaces (curbs, manhole frames) with emulsified asphalt or asphalt cement prior to laying new pavement. Prevent staining of adjacent surfaces.

3.5 PAVEMENT APPLICATION

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A. General: Place asphalt concrete mixture on approved, prepared base in conformance with this section.

B. Pavement Mix:

1. Prior to Paving:

a. Sweep primed surface free of dirt, dust, or other foreign matter.

b. Patch holes in primed surface with asphalt concrete pavement mix.

c. Blot excess prime material with sand.

2. Spread mix at minimum temperature of 250 degrees F.

3. Place asphalt concrete pavement mix in two equal lifts.

4. Compacted Lift Thickness:

a. Minimum: Twice maximum aggregate size, but in no case less than 1 inch.

b. Maximum: 2 inches.

5. Total Compacted Thickness: As shown.

6. Apply such that meet lines are straight and edges are vertical. 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.

7. Asphalt shall be placed to obtain a smooth, continuous surface free of pulls and tears in asphalt-paving mat.

8. Collect and dispose of segregated aggregate from raking process. Do not scatter material over finished surface.

9. Joints:

a. Offset edge of each layer a minimum of 6 inches so joints are not directly over those in underlying layer.

b. Offset longitudinal joints in roadway pavements so longitudinal joints in wearing layer coincide with pavement centerlines and lane divider lines. Do not construct joint in wheel path.

c. Form transverse joints by cutting back on previous day’s run to expose full vertical depth of layer.

d. Do not pass rollers over the unprotected end of a freshly laid mixture.

10. Succeeding Lifts: Apply tack coat to pavement surface between each lift.

11. After placement of pavement, seal meet line by painting a minimum of 6 inches on each side of joint with cut-back or emulsified asphalt. Cover immediately with sand.

C. Compaction:

1. 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-place compactors in areas inaccessible to rollers.

a. Complete compaction before mix temperature cools to 185 degrees F.

2. Breakdown rolling: Complete breakdown or initial rolling immediately after rolling joints and outside edge. Examine surface immediately after breakdown

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rolling for indicated crown, grade, and smoothness. Correct laydown and rolling operations to comply with requirements.

3. 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:

a. Average Density: 92 percent of reference maximum theoretical density according to ASTM D 2041, but not less than 90 percent nor greater than 96 percent.

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

5. 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.

6. Protection: After final rolling, do no permit vehicular traffic on pavement until it has cooled and hardened.

7. Erect barricades to prevent vehicular traffic on pavement until it has cooled enough to not become marked.

D. Tolerances:

1. General: Conduct measurements for conformity with crown and grade immediately after initial compression. Correct variations immediately by removal or addition of materials and by continuous rolling.

2. Pavement thickness:

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

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

3. Completed Surface or Wearing Layer Smoothness:

a. Uniform texture, smooth, and uniform to crown and grade.

b. Maximum Deviation: 1/8 inch from lower edge of a 10-foot straightedge, measured continuously parallel and at right angle to centerline.

c. If surface of completed pavement deviates by more than twice specified tolerances, remove and replace wearing surface.

4. Transverse Slope Maximum Deviation: 1/4 inch in 12 feet from rate of slope shown.

5. Finished Grade:

a. Perform field differential level survey on maximum 50-foot meter grid and along grade breaks.

b. Maximum Deviation: 0.02 foot from grade shown.

6. Remove and replace mixtures that become loose and broken, mixed with dirt or in any way defective, with fresh hot mixture and compacted to conform with the surrounding area.

E. Seal Coat:

1. General: Apply seal coat of paving grade or emulsified asphalt to finished surface at longitudinal and transverse joints, joints at abutting pavements, areas where asphalt concrete was placed by hand, patched surfaces, and other

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areas as directed.

2. Preparation:

a. Maintain surfaces that are to be sealed free of holes, dry, and clean of dust and loose material.

b. Seal in dry weather and when temperature is above 40 degrees F.

3. Application:

a. Fill cracks over 1/16 inch in width with asphalt-sand slurry or approved crack sealer prior to sealing.

b. When sealing patched surfaces and joints with existing pavements, extend minimum 6 inches beyond edges of patches.

3.6 FIELD QUALITY CONTROL

A. General: Field pacement testing shall be performed by a testing laboratory approved by the

Contracting Officer at the Contractor's expense

B. The relative density after compaction shall be 95 percent of the density obtained by using ASTM D 1188 or D 2726. A properly calibrated nuclear asphalt testing device shall be used for determining the field density of compacted asphalt concrete, or slabs or cores may be laboratory tested in accordance with ASTM D 1188.

C. Density testing shall be performed once for each 200 tons of asphalt concrete placed each day.

D. Asphalt shall be replaced and compacted where core tests are taken.

E. Remediation

1. In case the test of the base or pavement shows non-compliance with the required density, the Contractor shall accomplish such remedy as may be required to ensure compliance.

2. Subsequent testing to show compliance shall be paid by the Contractor.

END OF SECTION 32113