20-02547 Superpave Wearing Course.pdf

Job No. WCON 1509

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SECTION 02547

SUPERPAVE ASPHALT MIXTURE DESIGN,

HMA BINDER AND WEARING COURSE

PART 1 GENERAL

1.1 DESCRIPTION

A. This work shall consist of installing a certified plant-mixed HMA Binder or

Wearing course on a prepared surface within reasonably close conformity to the lines, grades and limits shown on the construction documents. The base course shall be constructed to the minimum compacted depth and density and to the distances below the finished grade, as indicated in the construction documents.

1.2 DESIGN STANDARDS

B. Unless otherwise indicated, the following design standards shall be used:

1. Mix Design – 19mm. - Binder

9.5mm - Wearing

2. Equivalent Single Axle Load – 3.0 to 10.0 million.

3. Performance Grade – PG 64-22.

4. Mat Thickness – 50mm (2 inches) Binder Course

40mm (1-1/2 inches) Wearing Course

5. Skid Resistance Level (SRL) – Level H

B. All standards shall be in accordance with PennDOT Publication 408, latest edition, Sections 309 and 409.

1.3 MIXTURE ACCEPTANCE

A. For Borough Roads, Certification Acceptance level will be used. Criteria for acceptance shall be as specified in PennDOT Publication 408, Section 409.2(f).

B. Provide PennDOT Form CS-4171 from a plant approved in Bulletin 15. Attach all QC test results to the form. Certify mixture as specified in Section 106.03 and the requirements of Section 409.

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C. Provide all forms and supporting certifications to the Engineer a minimum of

10-days prior to the commencement of work.

D. For State Highways, mixture acceptance may be by other methods, as specified in

PennDOT Publication 408, Section 409. It is incumbent upon the contractor to contact the PennDOT representative to determine which criteria for acceptance will be used for the specific project.

1.4 MATERIAL

A. All material shall be in accordance with Section 409.2 of PennDOT Publication

408, latest edition.

1.5 EQUIPMENT

A. Hauling Equipment.

1. Haul the mixtures in tightly sealed vehicles that do not contain petroleum oils, solvents, or other materials that adversely affect the mix.

2. Provide covers of sufficient size and quality to protect the entire load under all conditions.

3. Maintain the proper and uniform temperature specified in Section

409.3(h)1 of PennDOT Publication 408, latest edition.

4. Provide insulation on all sides of the truck body, a double-walled body, or a heated body when the air temperature is below 50°F.

B. Bituminous Pavers

1. Use self-contained, power-propelled units with activated screeds or activated strike-off assemblies and with automatic screed controls capable of producing a finished surface of the specified evenness and texture.

2. Provide heated units capable of spreading and finishing the mixture to the widths and depths indicated.

3. Provide units capable of being operated at forward speeds consistent with the satisfactory laying of the mixture and equipped with receiving hoppers having sufficient capacity for uniform spreading and equipped with distribution systems that place the mixture uniformly in front of the screeds.

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4. Do not use any equipment that tears, shoves, or gouges the mixture or that causes tracks, indented areas, flushing segregation or other permanent blemishes. Do not use blade graders or other earthmoving equipment.

C. Rollers

1. Use steel-wheel, pneumatic-tire or vibratory rollers weighing not less than ten (10) tons, as specified in Section 108.05(c)3 of PennDOT Publication

408, latest edition. Operate rollers according to manufacturer’s recommendations.

1.6 CONSTRUCTION METHODS

A. Time Restrictions

1. Do not place paving mixtures from November 1 to March 31 unless written permission is obtained from Borough or State Officials.

B. Weather Limitations

1. Do not place base course when the air or prepared surface temperature is

40°F or lower.

2. If work is halted because of weather conditions, the Contractor may be permitted to place limited quantities of material that is en route to the project provided the placement is approved by the Project Representative on site.

3. Should the conditions not permit the material to be placed, the Contractor shall have no recourse for payment of any unused material.

C. Preparation of Existing Surface.

1. Remove and dispose of all loose and foreign material including, dirt, dust, mud, excess joint and crack sealer and all other foreign material. Employ a power or portable truck broom for large areas.

2. Should excessive amounts of dirt and/or dust be embedded within the base course, the Engineer may order the surface to be blown off with compressed air to remove this material.

3. Fill cracks where directed by the Engineer prior to paving. Any broken or faulty road surface, holes, or depressions are to be excavated to a firm foundation, dried, tack or prime coated and leveled with suitable bituminous patching material prior to overlay.

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4. All surfaces to receive either binder or wearing course must be dry.

5. Before overlaying any surfaces, apply specified tack coat at an average rate of 0.05 gal/sq.yd. in accordance with PennDOT Publication 408, Section 460 or as directed by the Engineer. Tack coat shall be applied no more than three (3) hours before the street is paved. Dripping or pouring the tack coat even from a distributor truck will be cause for suspension of work until proper equipment is brought to the job.

6. Paint all vertical surfaces of curbs, structures, gutter and pavements that will be in contact with bituminous mixtures with a uniform coating of bituminous material, Class E6 or E8.

7. All necessary start and stop cuts and cuts around inlets and at the end of paving for each limit of paving are to be made by the Contractor.

D. Spreading and Finishing.

1. Unless otherwise directed, deliver, place and compact pawns, mixtures during daylight hours.

2. Ensure that mixtures are delivered and placed at the following laying temperatures. Ensure mixture does not contain lumps of cold material

TEMPERATURE OF MIXTURE

CLASS OF MATERIAL MIN (°F) MAX (°F)

PG 64-22 265 320

For other classes of material, refer to PennDOT Publication 408, Section

409.2 for temperature ranges.

3. Spread and strike off the mixture for the entire lane width or as much lane width as practical. Adjust screed assemblies to provide the required cross section and depth. After spreading, do not add any mixture to the mat that is segregated, below the minimum temperature, contains either a deficiency or excess of asphalt, or is otherwise unsuitable.

4. In areas where mechanical spreaders cannot be used, place and screed the mixture with suitable hand tools. Do not use rakes.

5. Install the binder or wearing course to within 6 mm (1/4-inch) of final elevations. Remove and replace any irregularities more than 6 mm

(1/4-inch).

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6. Sealing of each overlaid road shall be performed within fourteen (14) days of paving.

7. All curbs, edges, inlets, manholes, water boxes, driveways, etc. Must be sealed with AC-20 or equal (not tack coat) after resurfacing. All driveways shall have screenings placed over the AC-20 while it is still hot.

E. Joints

1. Longitudinal.

a. Plan joint locations to ensure that the joint in the top layer is at the approximate pavement centerline for two-lane roadways and within 300 mm (12-inches) of the lane lines for roadways with more than two lanes. Offset joints in a layer from the joint in the layer immediately below by approximately 150 mm (6-inches).

b. If traffic or other causes distort the lane edge, restore it to its original shape using either a vertical or notched wedged joint per

Section 409.3 of PennDOT Publication 408, latest edition.

2. Transverse.

a. Construct joints perpendicular to the pavement centerline.

b. Provide a true vertical surface and cross section throughout the entire joint. All joints within the wearing course shall be saw joints.

c. Paint the joint face with a thin coating of bituminous material before placing fresh mixture against the joint face.

F. Compaction.

1. Compact the mixture to achieve the density acceptance requirements and to eliminate all roller marks.

2. Compact the mixture while it is in the proper condition. Adjust roller speed, amplitude, frequency pattern and roller size to eliminate displacement, shoving, cracking and aggregate breakage. Satisfactorily correct all displacement.

3. Maintain wheels of the steel-wheel rollers moist and clean to prevent the mixture from adhering to the wheels.

4. For areas inaccessible to rollers, compact with mechanical vibrating hand tampers.

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G. Mat Density Acceptance.

1. Density acceptance level will be either by Non-Movement or Optimum –

Rolling Pattern as outlined in PennDOT Publication 408, Section 409.3.

2. Density limits shall comply with Table E of Section 409.3, Publication

408, latest edition.

H. Field Technician.

1. Provide a certified HMA field technician in accordance with the qualifications outlined in Publication 351 to control placement of the bituminous mixtures. The certified HMA field technician must be onsite and carry a valid certification card during placement of all HMA mixtures.

I. Protection of Courses.

1. Do not allow vehicular traffic or loading on newly compacted courses for a minimum of three (3) hours and until adequate stability and adhesion is obtained and the material has cooled to 140°F or less.

J. Surface Tolerance.

1. Extreme care shall be exercised by the contractor to insure that a continuous grade exists along the new paving and that no pockets exist for water to collect and remain dormant. If any such pockets do occur, the contractor at his expense shall be required to correct the problem to the satisfaction of the Borough Engineer.

2. Surface tolerance shall be as defined by Section 409.3(L). The pavement will be considered defective if irregularities are more than 3/16-inch over a 10-foot length.

K. Defective Work.

1. Remove and replace all work determined to be defective by the Engineer.

Defective work will be as defined in PennDOT Publication 408, latest edition, Sections 105, 309 and 409.

2. Defective work will not be measured for payment until it is satisfactorily corrected.

3. All cutting of test holes, checking of depth, refilling, and compacting shall be done by the contractor at his expense and as directed by the Engineer.

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END OF SECTION