02511_Hot-Mixed_Asphalt_Paving.DOC

SECTION 02511 ‑ HOT‑MIXED ASPHALT PAVING

Part 1 - GENERAL

1.1. SUMMARY

A. This Section includes provisions for hot‑mixed asphalt paving over prepared subbase.

B. Prepared subbase is specified in another Section 02505, “Gravel and Crush Stone Base and Subbase Course”.

C. Proof rolling of prepared subbase is included in this Section.

D. Saw‑cutting of edges of existing pavement when applicable.

1.2. SUBMITTALS

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

1.3. SITE CONDITIONS

A. Weather Limitations: Apply prime and tack coats when ambient temperature is above 40 degrees F (10 degrees C) and when temperature has not been below 35 degrees F (1 degree C) for 12 hours immediately prior to application. Do not apply when base is wet or contains an excess of moisture.

B. Construct hot‑mixed asphalt surface course when atmospheric temperature is above 40 degrees F (10 degrees C) and when base is dry. Base and binder courses may be placed when air temperature is above 35 degrees F (7 degrees C).

C. Grade Control: Establish and maintain required lines and elevations.

Part 2 - PRODUCTS

2.1. MATERIALS

A. If asphalt materials are not specified on the Drawings, use the following Engineer designated asphalt mixes:

1. Mixes from a State list or approved source.

2. Mix designs prepared according to AASHTO R12-85.

B. Asphalt Mixing Plants: State approved or conforming to AASHTO M156-86.

C. Materials in Asphalt Mixes: According to State specifications.

D. Tack Coat: Emulsified asphalt; ASTM D 977.

E. Prime Coat: Cut-back asphalt type, ASTM D2027; (MC-30, MC-70 or MC-250) or ASTM D 2028; (RC-70 or RC-250).

F. Paving Equipment: Subject to Owner’s Representative review.

2.2. ASPHALT‑AGGREGATE MIXTURE

A. Provide plant‑mixed, hot‑laid asphalt‑aggregate mixture complying with ASTM D 3515.

Part 3 - EXECUTION

3.1. SURFACE PREPARATION

A. Proof‑roll prepared subbase surface to check for unstable areas and areas requiring additional compaction.

B. Notify Owner’s Representative of unsatisfactory conditions. Do not begin paving work until deficient subbase areas have been corrected and are ready to receive paving.

C. Tack Coat: Apply to contact surfaces of previously constructed asphalt or Portland cement concrete and surfaces abutting or projecting into hot‑mixed asphalt pavement. Distribute at rate of 0.05 to 0.15 gal. per sq. yd. of surface. Allow to dry until at proper condition to receive paving.

D. Exercise care in applying bituminous materials to avoid smearing of adjoining concrete surfaces. Remove and replace or clean damaged surfaces.

3.2. PLACING MIX

A. General: Place hot‑mixed asphalt mixture on prepared surface, spread, and strike off. Spread mixture at minimum temperature of 250 degrees F and maximum temperatures at 325 degrees F. Place areas inaccessible to equipment by hand. Place each course to required grade, cross‑section, and compacted thickness.

B. Paver Placing: Place in strips not less than 10 feet wide, unless otherwise acceptable to Owner’s Representative. After first strip has been placed and rolled, place succeeding strips and extend rolling to overlap previous strips. Complete binder course for a section before placing surface course. Repair irregularities in binder prior to placement of finish course by shimming, truing, and leveling course or by other Engineer reviewed methods.

C. Immediately correct surface irregularities in finish course behind paver. Remove excess material forming high spots with shovel or lute.

D. Joints: Make joints between old and new pavements, or between successive days’ work, to ensure continuous bond between adjoining work. Construct joints to have same texture, density, and smoothness as other sections of hot‑mixed asphalt course. When matching existing pavement where joint is rounded off or irregular, the joint shall be saw cut with a walk behind saw with Diamond Blade. The joint shall be straight and uniform. Old asphalt shall be removed in a manner not to damage new joint. Clean contact surfaces and apply tack coat.

3.3. ROLLING

A. General: Begin rolling when mixture will bear roller weight without excessive displacement.

B. Compact mixture with hot hand tampers weighing not less than 25 pounds and having bearing area not greater than 48 square inches, or vibrating plate compactors in areas inaccessible to rollers.

C. Breakdown Rolling: Accomplish breakdown or initial rolling immediately following rolling of joints and outside edge. Check surface after breakdown rolling and repair displaced areas by loosening and filling, if required, with hot material.

D. Second Rolling: Follow breakdown rolling as soon as possible, while mixture is hot. Continue second rolling until mixture has been evenly compacted.

E. Finish Rolling: Perform finish rolling while mixture is still warm enough for removal of roller marks. Continue rolling until roller marks are eliminated and course has attained 95 percent laboratory density.

F. Patching: Remove and replace paving areas mixed with foreign materials and defective areas. Cut out such areas and fill with fresh, hot‑mixed asphalt. Compact by rolling to specified surface density and smoothness.

G. Protection:

1. Repair or replace damage to curbs, sidewalks, light poles or other structures caused during placing or compacting, at no additional expense to Contract.

2. After final rolling, do not permit vehicular traffic on pavement until mixture has set a minimum of 12 hours, unless otherwise accepted by Owner’s Representative.

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

3.4. FIELD QUALITY CONTROL

A. Thickness: In‑place compacted thickness tested in accordance with ASTM D 3549 will not be acceptable if the following allowable variations are exceeded, or if the average of half the samples tested (using the thinnest samples) is below the design thickness without consideration of tolerances.

1. Base Course: Plus ½ inch or minus ¼ inch.

2. Surface Course: Plus ½ inch or minus ¼ inch.

3. Total Asphalt Depth: Plus ½ inch or minus ¼ inch.

B. Surface Smoothness: Test finished surface of each hot‑mixed asphalt course for smoothness, using 16‑foot straightedge applied parallel with and at right angles to centerline of paved area. Surfaces will not be acceptable if the following tolerances for smoothness are exceeded:

1. Base Course Surface: 5/16 inch.

2. Binder Course Surface: ¼ inch.

3. Wearing Course Surface: 3/16 inch.

4. Crowned Surfaces: Test with crowned template centered and at right angle to crown. Maximum allowable variance from template is ¼ inch.

5. Check surface areas at intervals as reviewed by Engineer.

C. If compaction of asphalt is questioned by the Engineer, cored samples will be tested to verify 95 percent laboratory density.

3.5. REPAIR OF DAMAGED PAVEMENT

A. Saw-cut all damaged areas perpendicular or parallel to edge of pavement.

B. Cut back top course one foot (1’) minimum beyond damaged area and mill one inch (1”) of pavement.

C. Install new top to match existing pavement, as per specifications and plans.

END OF SECTION

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HOT-MIXED ASPHALT PAVING

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HOT-MIXED ASPHALT PAVING