400part2.pdf

Section 404—Major Cold Asphalt Concrete Pavement

Description

404.01 Work. Construct one or more courses of cold asphalt concrete pavement on a prepared surface that has been approved in writing by the CO.

Cold asphalt concrete pavement grade is designated as shown in table 703-5 or table 703-6.

Cutback asphalt grade is designated as shown in AASHTO M 81, AASHTO M 82, or ASTM D 2026. Emulsified asphalt grade is designated as shown in AASHTO M 140 or M 208.

A prepaving conference will be held at least 10 working days prior to the beginning of paving operations. At that time, the Contractor and the CO will discuss methods of accomplishing all phases of the paving work, including laydown operations, work schedules, work force, quality control systems, spill prevention and contingency plans, and asphalt concrete mix delivery.

Materials

404.02 Requirements. Ensure that the material conforms to specifications in the following subsections:

Antistrip Additive...............................................................702.07 Cement...............................................................................701.01 Choker Aggregate...............................................................703.11 Cold Asphalt Concrete Pavement Aggregate......................703.08 Cutback Asphalt.................................................................702.02 Emulsified Asphalt.............................................................702.03 Hydrated Lime....................................................................725.03 Mineral Filler......................................................................725.05 Water..................................................................................725.01

Ensure that mixing temperature meets the requirements specified in Subsec-tion 702.04.

Construction

404.03 Composition of Mixture (Job-Mix Formula). Ensure that the composition of cold asphalt concrete mixtures conforms to the following:

(a) Furnish a job-mix formula at least 21 days prior to production. Base the formula on a mix design using the type and grade of asphalt material that will be furnished for the project and of aggregate that will be produced for the project. Acceptable job-mix procedures and criteria are found in AI Manual Series number 14 and number 19. After reviewing the Contractor’s proposed job-mix formula, the CO will determine a job-mix formula with TV’s and will notify the Contractor in writing.

(b) In the proposed job-mix formula, include definite single-value TV’s for:

(1) The percentage of aggregate passing each specified sieve, based on the dry weight of aggregate. These percentages shall be within the range shown in Subsection 703.08, table 703-5 or table 703-6, as applicable.

(2) The percentage of bituminous material to be added, based on the total weight of mixture and corresponding residual asphalt content.

(3) The kind and percentages of additives to be used.

(4) The percentage of water, based on the total dry weight of the mixture.

(5) For emulsified asphalt only, the percentage to total fluids at compaction, based on the total dry weight of the mixture.

404.04 Performance. Perform construction in accordance with the following:

(a) Mixing Plant. Use asphalt mixing plants or pugmills that:

(1) Are manufactured for that purpose.

(2) Are in good working order.

(3) Are equipped with weighing or volumetric equipment capable of providing accurate control of the material entering the mixer.

(4) Interlock the aggregate feed controls with the asphalt material and other additives.

(b) Pavers. Use pavers that are:

(1) Self-contained, power-propelled units with adjustable vibratory screeds with full-width screw augers.

(2) Capable of spreading and finishing courses of asphalt mixture in widths at least 300 mm more than the width of one lane.

Section 404

(3) Equipped with a receiving hopper with sufficient capacity to ensure a uniform spreading operation.

(4) Equipped with automatic feed controls that are properly adjusted to maintain a uniform depth of material ahead of the screed.

(5) Capable of being operated at forward speeds consistent with satisfactory laying of the mixture.

(6) Capable of producing a finished surface of the required smoothness and texture without segregating, tearing, shoving, or gouging the mixture.

(7) Equipped with automatic screed controls with sensors capable of sensing grade from an outside reference line, sensing the transverse slope of the screed, and providing the automatic signals that operate the screed to maintain grade and transverse slope.

(c) Surface Preparation. Prepare the surface in accordance with Sections 304, 306, 307, and 308, as applicable. Apply an asphalt tack coat to contact surfaces of curbing, gutters, manholes, and other structures in accordance with Section 407.

(d) Weather Limitations. Place cold asphalt concrete pavement on unfrozen, reason-ably dry surface when the temperature of the road surface, in the shade, is above 15 °C, and it is not raining or snowing, or predicted to rain or snow within 24 hours after placement.

(e) Mixing. Introduce the material into the mixing plant according to the approved job-mix formula. Control the moisture content by adding water in the plant, covering the stockpile, drying the aggregate, or a combination of these methods as necessary to comply with the job-mix formula. When approved in writing by the CO, additives such as lime or cement may be incorporated into the mixture to correct moisture content.

When the aggregate is combined with asphalt materials other than emulsified asphalt, ensure that the aggregate does not contain more than 3 percent moisture and is at a temperature not less than 16 °C and not more than 107 °C. When the aggregate is combined with emulsified asphalt, ensure that the aggregate is at a temperature not less than 16 °C and not more than 79 °C. Determine the mixing time for each phase of the mixing operation from the nature of the aggregates, the job-mix formula, and the size of the batch. If the mixture is stockpiled, do not allow the pile to segregate such that the emulsified asphalt breaks.

(f) Hauling. Use vehicles conforming to Subsection 402.11.

(g) Placing & Finishing. Do not use mixtures produced from different plants unless the mixtures are produced in accordance with the same job-mix formula, use material from the same sources, and are approved.

Place the mixture with a paver that conforms to Subsection 404.04(b). Control horizontal alignment using a reference line. Automatically control the grade and slope from reference lines, a ski and slope control device, or dual skis. Use skis with a minimum length of 6 m.

Offset and locate longitudinal joint according to Subsection 402.12.

For dense-graded mixtures, allow the surface to cure for not less than 10 days, and for open-graded mixtures, not less than 4 days, before covering with the next course.

During this period, maintain the surface and keep it free of corrugations. Use an approved material to patch all holes. Remove all excess blotter, dirt, or other objectionable substances before placing the following course or treatment.

(h) Compacting. Perform initial compaction through a minimum of three complete coverages with a steel-wheel roller that meets the requirements of Subsection 203.15(b). If necessary for dense-graded mixtures, aerate the material by periodi-cally moving and exposing it in the stockpile or through manipulation in a windrow to remove excess moisture or cutter. When DESIGNATED IN THE SCHEDULE OF ITEMS, and prior to intermediate rolling, apply choker aggregate to the top layer only using aggregate spreading equipment designed for the controlled spreading of fine material. Uniformly spread the material to a depth that, when compacted, is sufficient to fill the voids of the asphalt concrete mat. Remove excess choker material by brooming.

Perform intermediate compaction through a minimum of two complete coverages of a self-propelled pneumatic-tire roller with a maximum tire pressure of 275 kPa.

Perform final compaction through two complete coverages with a static roller that meets the requirements of Subsection 203.15, and until all roller marks are elimi-nated. For open-graded mixtures, use a steel-wheel roller. When no choker aggregate is required, perform final compaction while the emulsion is still tacky.

Along forms, curbs, headers, walls, and other places not accessible to the rollers, use other equipment to obtain the minimum compaction of the mixture.

404.05 Acceptance Sampling & Testing. Perform acceptance sampling and testing in accordance with Subsections 402.15 through 402.18, with the following modifications:

(a) Use table 404-1.

(b) Use table 404-2.

a. Use only for gravel sources.

b. An undeveloped source is a source that has not supplied aggregate for asphalt concrete within 365 days of the start of producing asphalt concrete for this particular project.

S ection 404

Table 404-1.—Sampling and testing.

Type of Acceptance Material or

Product Property or

Characteristics Test Method or Specification Frequency Sampling Point

Production certification

(Subsection 105.04)

Asphalt Contract requirements

AASHTO M 81,

AASHTO M 82,

AASHTO M 140,

AASHTO M 208,

ASTM D 2026,

as applicable

Daily –

Tested conformance

Material source Los Angeles abrasion

AASHTO T 96 Three times for each undeveloped source, or b

Material source

Sodium sulfate soundness

AASHTO T 104 once for all other sources

Durability index (coarse and fine)

AASHTO T 210

Aggregate Fracture faces (coarse) a FLH T 507 Three times for each undeveloped source, or b once for all other sources

Cold feed prior to entering mixer

Sand equivalent value (fine)

AASHTO T 176,

alternate method number 2 (referee method)

Asphalt Sample Subsection 105.04(b)

Once for each 500 t of mix, and not more than three times per day

At point of shipment delivery

Job-mix formula Contract requirements

Subsection 404.03

Once for each product or material change

Mix evaluation Cold asphalt concrete pavement

Asphalt content

Gradation

AASHTO T 164,

method B or E

AASHTO T 30

Once for each 500 t, and not more than three times per day

At plant, in hauling units,, or behind machine before rolling

Mixture Characteristica Tolerances

Residual asphalt content TV ± 0.5 Total fluids in aggregate at compaction TV ± 1.5

a. For sieve size tolerance, refer to table 703-5 or 703-6, according to the grading DESIGNATED IN THE

SCHEDULE OF ITEMS.

(c) Compaction for the lot will be accepted if the requirements specified in Subsection 404.04(g) have been met and all roller marks are eliminated.

Measurement

404.06 Method. Use the method of measurement that is DESIGNATED IN THE

SCHEDULE OF ITEMS.

Calculate tonnage as the weight used in the accepted pavement. Make no deduction for the weight of bituminous material or water. No separate payment will be made for water or additives used in the mixture.

Payment

404.07 Basis. The accepted quantities will be paid for at the contract unit price for each PAY ITEM DESIGNATED IN THE SCHEDULE OF ITEMS, except that payment for sampling and testing will be made as follows:

(a) Twenty-five percent of the lump sum, not to exceed 0.5 percent of the original contract amount, will be paid after all the testing facilities are in place, qualified sampling and testing personnel are identified, and the work being tested has started.

(b) Payment for the remaining portion of the lump sum will be prorated based on the total work completed.

(c) Payment for all or part of this pay item may be withheld if the Government assurance tests invalidate the Contractor’s testing.

Payment will be made under:

Pay Item Pay Unit

404 (01) Cold bituminous pavement, _________ grading................ Ton

404 (02) Cutback asphalt, grade ______________.......................... Ton

404 (03) Emulsified asphalt, grade _____________........................ Ton

404 (04) Choker aggregate............................................................... Ton

404 (05) Sampling and testing....................................................Lump Sum

Table 404-2—Mix tolerances.

Section 405—Minor Cold Asphalt Concrete Pavement

Description

405.01 Work. Construct one or more courses of cold asphalt concrete plant mix on a prepared surface as SHOWN ON THE DRAWINGS. Have the surface approved by the CO in writing prior to placing cold asphalt concrete plant mix.

Cutback asphalt grade is designated as shown in AASHTO M 81 or M 82. Emulsi-fied asphalt grade is designated as shown in AASHTO M 140 or M 208.

Materials

405.02 Asphalt Material. Ensure that asphalt material meets the requirements specified in Subsection 702.02 or 702.03, as applicable. The exact percent of asphalt material and the grade to be used will be furnished by the CO after requirements in Subsection 405.05 have been reviewed and evaluated. Ensure that mixing tempera-tures shall meet the requirements specified in Subsection 702.04.

405.03 Aggregate. Ensure that aggregate meets the requirements specified in Subsection 703.09, except for aggregate gradation. Maximum gradation size or suggested gradation designations will be SHOWN ON THE DRAWINGS.

405.04 Additives. Additives, such as filler, hydrated lime, and antistrip agents, may be used as necessary to meet specifications. Ensure that filler meets the requirements of AASHTO M 17; hydrated lime meets the requirements of AASHTO M 216, type Ν; antistrip materials meet the requirements specified in Subsection 702.07; and choker aggregate meets the requirements specified in Subsection 703.11.

405.05 Job-Mix Formula. Submit a job-mix formula and supporting documenta-tion, test results, and calculations for the material to be incorporated into the work.

Include copies of laboratory test results and mix design data that demonstrate that the properties of the aggregate, additives, and mixture meet those requirements and criteria of local public agencies or the AI. After reviewing the Contractor’s proposed job-mix formula, the CO will determine the final values for the job-mix formula to be used and notify the Contractor in writing.

Construction

405.06 Asphalt Concrete Mixing Plant. Ensure that plants used for preparing cold asphalt concrete mixtures are manufactured for that purpose, in good repair, and capable of mixing the material to a uniform consistency.

405.07 Hauling Equipment. Ensure that trucks used for hauling asphalt concrete mixtures have tight, clean, smooth metal beds that have been thinly coated with a material to prevent the mixture from adhering to the beds. Do not use petroleum derivatives or other coating material that contaminates or alters the characteristics of the mixture. Drain truck beds prior to loading, and ensure that each truck has a cover to protect the mixture from weather. When necessary to ensure that the mixture will be delivered at the specified temperature, ensure that truck beds are insulated and covers securely fastened.

405.08 Pavers. Use pavers that are in good working order and have an adjustable vibrating screed or strike-off assembly, and an auger ahead of the screed to distribute the mixture. Use pavers that are capable of spreading and finishing courses of asphalt concrete plant mix material in the lane widths and thickness SHOWN ON THE DRAWINGS. Unless otherwise SHOWN ON THE DRAWINGS, towed-type pavers and Layton-type pavers or graders may be used to place and spread the asphalt concrete plant mix material.

405.09 Rollers. Ensure that all rollers meet the requirements specified in Subsections 203.15(b), (c), and (d). Where it is impractical to operate larger rollers, 3- to 5-t rollers may be used. On walkways, 1-t rollers may be used.

405.10 Weather Limitations. Do not place the asphalt concrete mixture when the base course is frozen, when the average temperature of the underlying surface upon which the asphalt concrete mixture is to be placed is less than 10 °C in the shade, or when it is raining or snowing, or predicted to rain or snow within 24 hours after placement.

405.11 Conditioning of Existing Surface. Immediately before placing the asphalt concrete mixture, clean the existing surface of loose or deleterious material.

Before placing the asphalt concrete mixture, paint the contact surfaces of curbing, gutters, manholes, and other structures with a thin, uniform coating of asphalt material.

405.12 Control of Asphalt Concrete Mixture. Supply a certification from the mixing plant stating that the mix conforms to the approved job-mix formula. The CO may reject any batch, load, or section of roadway that appears defective in gradation, asphalt content, or moisture content. Do not incorporate material rejected before placement into the pavement. Remove any rejected section of roadway. No payment will be made for the rejected materials or the removal of the materials, unless the Contractor requests that the rejected material be tested, at the Contractor’s expense, under the following provisions:

(a) Obtain three representative samples and have them tested at a laboratory approved by the CO.

Section 405

(b) If test results show that the material conforms to the tolerance shown in table 405-1, payment will be made for the material and for its removal and testing.

Table 405-1.—Allowable tolerances.

405.13 Transporting, Spreading, & Finishing. Transport the mixture from the mixing plant to the point of use in vehicles that meet the requirements specified in Subsection 405.07.

Spread the mixture and strike it off to the grade and elevation established. Provide a maximum compacted lift thickness of 100 mm unless otherwise SHOWN ON THE

DRAWINGS.

Ensure that the longitudinal joint in any layer offsets that in the layer immediately below by approximately 150 mm. Where laydown requires placement of two adjacent panels to cover the surface of a traveled way, ensure that the longitudinal joint of the top layer is at the centerline. This requirement does not apply to turnouts, extra widening, or parking areas. Offset transverse joints in succeeding layers and in adjacent lanes at least 3 m.

On areas where irregularities or unavoidable obstacles make the use of mechanical spreading and finishing equipment impracticable, the mixture may be placed and finished by using hand tools.

405.14 Compaction. Perform compaction with rollers that meet the requirements specified in Subsection 405.09. Perform initial compaction with steel-wheel rollers for a minimum of three complete coverages. Between initial and final rolling on open-graded mixtures, apply a choker aggregate to the top layer only using aggregate spreading equipment designed for the controlled spreading of fine material. Uniformly spread the material to a depth that, when compacted, will be sufficient to fill the surface voids of the bituminous mat. Remove excessive choke material by brooming. Continue rolling, with a minimum of four complete coverages and until no roller tracks remain, and while the bituminous material is still tacky.

Mixture Characteristic Tolerances

Residual asphalt content Job-mix formula 6 0.5

Sieve size:

9.5 mm and larger Job-mix formula 6 5.0

4.75 to 9.49 mm Job-mix formula 6 7.0

76 µm to 4.74 mm Job-mix formula 6 5.0

75 µm Job-mix formula 6 2.0

Measurement

405.15 Method. Use the method of measurement that is DESIGNATED IN THE

SCHEDULE OF ITEMS.

Calculate the quantity of cold asphalt concrete plant mix as the tonnage of combined aggregate and asphalt material used in the accepted work. No separate payment will be made for asphalt material, water, or additives used in the mixture.

Payment

405.16 Basis. The accepted quantities will be paid for at the contract unit price for each PAY ITEM DESIGNATED IN THE SCHEDULE OF ITEMS.

Payment will be made under:

Pay Item Pay Unit

405 (01) Cold asphalt concrete plant mix, grade ____..................... Ton

405 (02) Cold asphalt concrete plant mix, grade ____..............Square Meter

Section 407—Asphalt Tack Coat

Description

407.01 Work. Apply an emulsified asphalt tack coat. Have the surface to be treated approved by the CO in writing prior to treatment.

Tack coat emulsified asphalt grade is designated as shown in AASHTO M 140 or M 208.

Materials

407.02 Requirements. Ensure that material conforms to the specifications in the following subsections:

Emulsified Asphalt.............................................................702.03 Water..................................................................................725.01

Construction

407.03 Equipment. Use equipment that conforms to specifications in Subsec-tion 410.04.

407.04 Surface Preparation. Immediately before the application of the tack coat, patch the surface to be treated and remove all foreign and loose material.

407.05 Weather Limitations. Apply asphalt tack coat on a dry, unfrozen surface when the surface temperature in the shade is above 5 °C and rising.

407.06 Asphalt Application. Where slow-setting emulsified asphalt is used, dilute it by adding an equal amount of water to the emulsified asphalt.

Apply the asphalt in accordance with Subsection 410.08 at a rate of 0.15 to

0.70 L/m2. When a tack coat cannot be applied with an asphalt distributor spray bar, apply the tack coat uniformly and completely by fogging with a hand spray attachment or by another approved method. Ensure that the surfaces of adjacent structures and trees are protected from splattering and marring.

If excess asphalt material is applied, squeegee the excess from the surface. Allow the tacked surfaces to completely cure before placing the covering course. Place the covering course within 4 hours of placing the tack coat.

407.07 Acceptance. Emulsified asphalt will be evaluated for acceptance under Subsection 106.05.

Provide the minimum number of samples specified in table 410-4.

Measurement

407.08 Method. Use the method of measurement that is DESIGNATED IN THE

SCHEDULE OF ITEMS.

Water used for diluting emulsified asphalt will not be included in the quantities for PAY ITEMS 407(01) or 407(02), and will not be paid for separately.

Payment

407.09 Basis. The accepted quantities will be paid for at the contract unit price for each PAY ITEM DESIGNATED IN THE SCHEDULE OF ITEMS.

Payment will be made under:

Pay Item Pay Unit

407 (01) Tack coat, grade ___.......................................................... Ton

407 (02) Tack coat, grade ___..........................................................Liter

Section 407

Section 408—Asphalt Prime Coat

Description

408.01 Work. Apply a cutback or emulsified asphalt prime coat. Have the surface approved in writing by the CO prior to applying the prime coat.

Prime coat asphalt grade is designated as shown in AASHTO M 140 or M 208 for emulsified asphalt, and AASHTO M 81 or M 82 for cutback asphalt.

Materials

408.02 Requirements. Ensure that material conforms to the specifications in the following subsections:

Blotter .................................................................................703.12 Choker Aggregate...............................................................703.11 Cutback Asphalt.................................................................702.02 Emulsified Asphalt.............................................................702.03 Water..................................................................................725.01

Construction

408.03 Equipment. Use equipment that conforms to Subsection 410.04.

408.04 Surface Preparation. Immediately before applying the prime coat, lightly blade the surface and roll it with a smooth-wheel roller. Ensure that the moisture content of the top 25 mm of the surface to be treated is slightly damp.

408.05 Weather Limitations. Apply prime coat when the air temperature in the shade and the pavement surface temperature are at least 10 °C and rising, and when the weather is not foggy or rainy.

408.06 Asphalt Application. When required by the CO, lightly spray the surface with water before applying the prime coat. In order to obtain optimum penetration, apply cutback asphalt in accordance with Subsection 410.08 at a rate of 0.45 to

2.25 L/m2.

Where using an emulsified asphalt that is not formulated as a penetrating prime coat material, dampen the roadway surface and scarify 25 to 50 mm deep. Dilute the emulsified asphalt by adding an equal amount of water. Apply the diluted emulsified asphalt in accordance with the Subsection 410.08 at a rate of 0.45 to 1.35 L/m2.

Immediately process, respread, and compact the material.

Cure surfaces primed with emulsified asphalt for not less than 24 hours, and surfaces primed with cutback asphalt for not less than 5 days before covering with the next course.

Until the next course is placed, maintain the primed surface and keep it free of corrugations.

Where traffic is routed over a primed surface before the asphalt material has been completely absorbed, or to minimize damage by rain, spread blotter to cover the unabsorbed asphalt. If an emulsified asphalt is used, use choker aggregate. When cutback asphalt is used, do not apply the blotter material for at least 4 hours following application of the asphalt. Remove all excess blotter, choke, dirt, or other deleterious material and repair all damaged areas before placing the next course.

Dispose of asphalt material in accordance with Subsection 202.04(a).

408.07 Acceptance. Cutback asphalt and emulsified asphalt will be evaluated for acceptance under Subsection 106.05.

Blotter will be evaluated for acceptance under Subsection 105.03.

Provide the minimum number of samples and tests specified in table 410-4.

Measurement

408.08 Method. Use the method of measurement that is DESIGNATED IN THE

SCHEDULE OF ITEMS.

Water used for diluting emulsified asphalt will not be included in the quantity for PAY ITEMS 408(01) or 408(02) and will not be paid for separately.

Payment

408.09 Basis. The accepted quantities will be paid for at the contract unit price for each PAY ITEM DESIGNATED IN THE SCHEDULE OF ITEMS.

Payment will made under:

Pay Item Pay Unit

408 (01) Prime coat, grade ___........................................................ Ton

408 (02) Prime coat, grade ___........................................................Liter

408 (03) Blotter............................................................................... Ton

408 (04) Blotter.........................................................................Cubic Meter

Section 408

Section 409—Slurry Seal

Description

409.01 Work. Apply an asphalt slurry seal mixture. Have the surface approved by the CO in writing prior to placing the slurry seal.

Slurry seal type is designated as shown in table 703-8.

Materials

409.02 Requirements. Ensure that material conforms to the specifications in the following subsections:

Emulsified Asphalt............................................................. 702.03(d) Mineral Filler......................................................................725.05 Slurry Seal Aggregate.........................................................703.10 Water..................................................................................725.01

Construction

409.03 Composition of Mixture (Job-Mix Formula). Furnish a slurry seal mixture of aggregate, water, emulsified asphalt, and additives in accordance with ASTM D 3910 and ISSA T 114. Ensure that the mixture meets the applicable aggregate gradation shown in table 703-8 and has the following residual asphalt contents, based upon weight of dry aggregate:

• Type I—Residual asphalt between 10.0 percent and 16.0 percent.

• Type II—Residual asphalt between 7.5 percent and 13.5 percent.

• Type III—Residual asphalt between 6.5 percent and 12.0 percent.

Submit a written job-mix formula for approval at least 21 days before production that includes the following:

(a) Aggregate Gradation Values. Provide the representative value for each sieve size for the aggregate blend.

(b) Emulsified Asphalt Content. Provide the residual asphalt content, as a percent by weight of dry aggregate.

(c) Samples. Provide samples of the aggregate, emulsified asphalt, and mineral filler when SHOWN ON THE DRAWINGS.

(d) Laboratory Test Reports & Mix Design Data. Provide copies of all laboratory test reports and mix design data verifying that the material meets the requirements of Subsection 409.02 and the job-mix formula.

The job-mix formula will be evaluated and approved in accordance with Subsec-tion 401.03.

409.04 Equipment. Furnish equipment with the following capabilities:

(a) Slurry Seal Mixer. Furnish a slurry seal mixer with the following features and capabilities:

(1) Self-propelled.

(2) Continuous-flow mixing.

(3) Calibrated controls.

(4) Easily readable metering devices that accurately measure all raw material before entering the pugmill.

(5) Automated system for sequencing in all raw material to ensure constant slurry mixture.

(6) Mixing chamber to thoroughly blend all ingredients together.

(7) Fines feeder with an accurate metering device for introducing additive into the mixer, where the aggregate is introduced into the mixer.

(8) A pressurized water system with a fog-type spray bar capable of fogging the surface immediately ahead of the spreading equipment at a rate of 0.13 to

0.27 L/m2.

(9) Proportioning system that is accurate for measuring all material independent of the engine speed.

(10) Minimum speed of 20 m/min and maximum speed of 55 m/min.

(11) Minimum storage capacity of 6 t.

(12) Capability in accordance with ISSA Performance Guidelines A 105.

Section 409

(b) Mechanical-Type Single Squeegee Spreader Box. Furnish with the following capabilities:

(1) Attaches to the slurry seal mixer.

(2) Flexible squeegee in contact with the surface to prevent loss of slurry.

(3) Adjustable to assure a uniform spread over varying grades and crowns.

(4) Adjustable in width with a flexible strike-off.

(5) Augers for uniform flow to edges.

(c) Auxiliary Equipment. Furnish hand squeegees, shovels, and other equipment necessary to perform the work. Provide cleaning equipment that includes, but is not limited to, power brooms, air compressors, water-flushing equipment, and hand brooms for surface preparation.

(d) Pneumatic-Tire Roller. When SHOWN ON THE DRAWINGS, provide a pneumatic-tire roller with the following features:

(1) Smooth tread tires of equal size.

(2) Minimum ground pressure of tire greater than 345 kPa.

409.05 Surface Preparation. Immediately before placing the slurry seal, clean the existing surface of loose or deleterious material.

409.06 Weather Limitations. Apply slurry seal when the air temperature in the shade and the surface temperature are at least 15 °C and rising, and when the weather is not foggy, rainy, or overcast.

409.07 Slurry Seal Application. Mix the slurry seal using a slurry seal mixer. Fog the surface with water immediately preceding the spreader.

Blend the additive with the aggregate using the fines feeder. Prewet the aggregate in the pugmill immediately before mixing with the emulsified asphalt. Stockpile aggregate accordingly to Subsection 305.04.

Mix the slurry seal for a maximum of 4 minutes. Ensure that the slurry seal mixture is of the desired consistency as it leaves the mixer, and that it conforms to the approved job-mix formula. If approved by the CO, the mineral filler and the emulsified asphalt content may be adjusted during construction to conform to variations in field conditions.

Carry sufficient slurry seal mixture in the spreader to completely cover the surface.

Spread the mixture with a mechanical-type single squeegee spreader box. In areas not accessible to the spreader box, use hand squeegees to work the slurry seal mixture.

Remove or repair ridges or bumps in the slurry surface.

When required, roll the slurry surface, providing a minimum of five coverages, to completely cure it prior to opening to traffic. Cure is complete when clear water can be pressed out of the slurry mixture with a piece of paper without discoloring the paper.

409.08 Acceptance. Emulsified asphalt will be evaluated for acceptance under Subsection 106.05.

Aggregate will be evaluated for acceptance under Subsection 105.03.

Provide the minimum number of samples and tests specified in table 409-1, in accordance with Section 160.

Measurement

409.09 Method. Use the method of measurement that is DESIGNATED IN THE

SCHEDULE OF ITEMS.

Payment

409.10 Basis. The accepted quantities will be paid for at the contract unit price for each PAY ITEM DESIGNATED IN THE SCHEDULE OF ITEMS.

Payment will be made under:

Pay Item Pay Unit

409 (01) Slurry seal, type ___...................................................Square Meter

S ection 409

a. Use in work permitted before sampling and testing for conformance.

b. See Subsection 105.03. Testing not required when using Government-provided material source.

c. An undeveloped source is a source that has not supplied slurry seal aggregate within 365 days of the start of producing slurry seal aggregate for this project.

Table 409-1.—Sampling and testing.

Type of Acceptance

Material or Product

Property or Characteristic

Test Method or Specification Frequency Sampling Point

Production certification

Emulsified asphalta

Contract requirements

AASHTO M 140 or M 208, as applicable

Each shipment –

Tested conformance

Material sourceb (Contractor-located source)

Los Angeles abrasion

AASHTO T 96 Three times for each undeveloped source,cor once for all other sources

Material source

Slurry seal aggregate

Gradation, table 703-8

Sand equivalent value

AASHTO T 27 and T 11

AASHTO T 176,

alternate method number 2 (referee method)

Once for each 1,700 m2, but not more than three times per day

Emulsified asphalt Sample Subsection 106.04(b)

Each tanker, including all trailers

At point of shipment delivery

Section 410—Asphalt Surface Treatment

Description

410.01 Work. Construct a single or multiple asphalt surface treatment course. Have the surface approved by the CO in writing prior to placing the asphalt surface treatment.

Surface treatment aggregate is designated as shown in tables 410-1, 410-2, and 410-3.

The grade of asphalt is designated as shown in AASHTO M 20 or M 226 for asphalt cement, Subsection 702.03 for emulsified asphalt, and AASHTO M 81 or M 82 for cutback asphalt, or in applicable State department of transportation specifications for the grade specified.

A presurface treatment conference will be held at least 10 working days prior to the beginning of surface treatment operations. At that time, the Contractor and the CO will discuss methods of accomplishing all phases of the work, including operations, work schedules, work force, quality control systems, spill prevention and contin-gency plans, and material application rates.

Materials

410.02 Requirements. Ensure that material conforms to the specifications in the following subsections:

a. See table 703-7 for aggregate gradations.

b. Aggregate weights are for aggregates that have a bulk specific gravity of 2.65, as determined by AASHTO T 84 and T 85. Make proportionate corrections when the aggregate furnished has a bulk specific gravity above 2.75 or below 2.55.

Table 410-1.—Approximate quantities of material for single-course surface treatment.

Treatment Designation and Aggregate Gradation

Sequence of Operations B C D E F

Apply asphalt material (L/m

Emulsified asphalt Cutback asphalt Asphalt cement

2.5 1.9 1.7

2.0 1.6 1.4

1.6 1.2 1.1

1.1 0.9 0.8

1.1 0.9 0.8

Spread aggregate a,b (kg/m

) 24 16 12 8 11

Table 410-2—Approximate quantities of material for multiple-course surface treatment (using cutback asphalt).

Section 410

a. See table 703-7 for aggregate gradations.

b. Aggregate weights are for aggregates that have a bulk specific gravity of 2.65, as determined by AASHTO T 84 and T 85. Make proportionate corrections when the aggregate furnished has a bulk specific gravity above

2.75 or below 2.55.

Asphalt Cement..................................................................702.01 Asphalt Surface Treatment Aggregate................................703.09 Blotter .................................................................................703.12 Cutback Asphalt.................................................................702.02 Emulsified Asphalt.............................................................702.03

Construction

410.03 Material Submittals. For surface treatments, submit the information and samples shown below for approval at least 21 days before production.

(a) Aggregate Samples. Provide 35 kg from each stockpile produced and the gradation range represented by each.

(b) Aggregate Gradation TV’s. Submit the proposed percentage of each stockpile to be used and the proposed TV for each sieve size.

Treatment Designation Aggregate Gradation a,b

Sequence of Operations CT–20 CT–24 CT–36 CT–44 CT–48

First course:

Apply asphalt material (L/m2) Spread aggregate (kg/m

Grading D Grading C Grading B

1.2

1.6

1.9

1.9

1.9

Second course:

Apply asphalt material (L/m

Spread aggregate (kg/m

Grading E Grading D Grading C

0.9

0.9

1.2

1.2

1.6

Third course:

Apply asphalt material (L/m )2

Spread aggregate (kg/m ) 2

Grading E

0.9

0.9

Totals:

Asphalt material (L/m ) 2

Aggregate (kg/m 2 ) 3.1

2.5

3.1

4.0

4.4

Table 410-3—Approximate quantities of material for multiple-course surface treatment (using emulsified asphalt or asphalt cementa).

Section 410

a. For asphalt cement spread rates, multiply the asphalt material spread rates shown in the table by 0.68.

b. See table 703-7 for aggregate gradations.

c. Aggregate weights are for aggregates that have a bulk specific gravity of 2.65, as determined by AASHTO T 84 and T 85. Make proportionate corrections when the aggregate furnished has a bulk specific gravity above

2.75 or below 2.55.

(c) Asphalt Temperature. Ensure that asphalt application temperatures conform to table 702-1.

(d) Spread Rates. Furnish proposed spread rates for the asphalt material and aggregate.

410.04 Equipment. Ensure that all equipment is in good working order. Furnish the equipment shown below:

(a) Asphalt Distributor. Furnish an asphalt distributor with the following features and capabilities:

(1) Capable of heating asphalt evenly.

(2) Full-circulation spray bar adjustable to at least 4.6 m wide.

Treatment Designation Aggregate Gradation b,c

Sequence of Operations ET–20 ET–24 ET–36 ET–44 ET–48

First course:

Apply asphalt material (L/m )2

Spread aggregate (kg/m ) 2

Grading D Grading C Grading B

1.6

1.9

2.5

2.1

2.3

Second course:

Apply asphalt material (L/m )2

Spread aggregate (kg/m ) 2

Grading E Grading D Grading C

1.1

1.3

1.6

2.1

2.3

Third course:

Apply asphalt material (L/m )2

Spread aggregate (kg/m ) 2

Grading E

1.0

1.1

Totals:

Asphalt material (L/m ) 2

Aggregate (kg/m ) 2 2.7

3.2

4.1

5.2

5.7

(3) Positive controls, including tachometer, pressure gage, volume-measuring device, or calibrated tank, to uniformly deposit asphalt over the full width within 0.08 L/m2 of the required rate.

(4) Thermometer for measuring the asphalt temperature in the tank.

(b) Rotary Power Broom. Furnish a rotary power broom equipped to control the vertical broom pressure.

(c) Pneumatic-Tire Rollers. Furnish a minimum of two pneumatic-tire rollers with the following features and capabilities:

(1) Minimum compacting width of 1.5 m.

(2) Minimum ground contact pressure of 550 kPa, with all tires exerting equal contact pressure.

(3) Gross weight adjustable within the range of 35 to 65 kg/mm of compaction width.

(4) Self-propelled.

(d) Aggregate Spreader. Furnish an aggregate spreader with the following features:

(1) Self-propelled.

(2) Minimum of four pneumatic tires on two axles.

(3) Positive controls to uniformly deposit the aggregate over the full width of asphalt within 10 percent by weight of the required rates.

(e) Two-Way Communication. Provide two-way radio communication between the asphalt distributor and aggregate spreader.

(f) Other Equipment. When approved, other equipment of proven performance may be used in addition to, or in lieu of, the equipment specified.

410.05 Surface Preparation. Immediately before placing any layer of the surface treatment, remove loose dirt and other objectionable material from the existing surface.

Apply surface treatments to an existing asphalt surface only when the surface is dry.

Prior to application, allow a newly constructed cold or road mix surface to cure for at

Section 410 least 21 days for a cutback asphalt mix, and at least 14 days for an emulsified asphalt mix, unless otherwise approved by the CO.

When applying surface treatments to existing aggregate surfaces, ensure that the surface is dry if the aggregate was primed, and slightly damp if not primed. If the aggregate surface is primed, allow a prime coat curing period of at least 5 days for cutback asphalt and 24 hours for emulsions, unless otherwise approved by the CO.

Fog seal patches SHOWN ON THE DRAWINGS or listed in the SPECIAL PROJECT SPECIFICATIONS using CSS–1 emulsion, diluted with an equal part of water, at 0.65 L/m2, unless another rate is SHOWN ON THE DRAWINGS.

410.06 Weather Limitations. Apply surface treatments with aggregate only when the ambient air and surface temperatures are above 18 °C and rising, when the weather is not foggy or rainy, and when rain is not forecast for at least 24 hours after application.

Apply fog seals only when the ambient air and surface temperatures are above 10 °C and rising, when the weather is not foggy or rainy, and when rain is not forecast for at least 24 hours after application.

For all work:

(a) Ensure that humidity is less than 75 percent as measured by the sling psychrometer method.

(b) Complete application of the surface treatment 2 hours before sunset.

(c) Unless otherwise approved by the CO, construct fog seals and single-course surface treatments between June 1 and September 1, and multiple-course surface treatments between June 1 and September 15.

410.07 Production Startup Procedures for Surface Treatment. Provide 7 days advance notice before constructing any asphalt surface treatments containing aggregate, and also use these startup procedures when resuming production after termination due to nonconforming work.

Calibrate each asphalt distributor’s bar height, nozzle angle, pump pressure, and longitude and transverse spread rates in accordance with ASTM D 2995. If different asphalt distributors are used throughout the project, calibrate each prior to use on the project.

On the first day of production of each surface treatment layer, whenever there is a change in the surface texture or the aggregate TV’s, construct a 150-m control strip one lane wide. Locate the control strip on the project as designated.

Construct the control strip using material, laydown, and compaction procedures intended for the remainder of the surface treatment. Cease production after construc-tion of the control strip until the material, the control strip, and the asphalt distributor calibration procedures are evaluated and accepted.

Acceptable control strips may remain in place, and will be accepted as a part of the completed surface treatment.

Repeat this control strip process until an acceptable control strip is produced.

410.08 Asphalt Application. Protect the surfaces of nearby objects to prevent spattering or marring. For transverse construction joints, spread building paper on the surface for a sufficient distance from the beginning and end of each application so that the flow through the distributor nozzles may be started and stopped on the paper.

The CO may make adjustments for variations in field conditions. Apply the asphalt uniformly with an asphalt distributor with the spray bar height set for triple overlap.

Move the distributor forward at the proper application speed at the time the spray bar is opened. Use care not to apply excess asphalt at the junction of spreads.

Ensure that the length of spread is no more than what can be covered with aggregate within 1 minute of the asphalt application.

Correct skipped areas or deficiencies. Remove and dispose of paper or other material used, in accordance with Subsection 202.04(a).

410.09 Aggregate Application. When using emulsified asphalt, moisten the aggregate to remove its dust coating.

Stockpile aggregate according to Subsections 305.03 and 305.04.

Apply the aggregate uniformly with an aggregate spreader immediately after the asphalt is applied. Operate the aggregate spreader so the asphalt is covered with the aggregate before wheels pass over it. During part-width construction, leave a strip of the sprayed asphalt approximately 150 mm wide uncovered to permit an overlap of the asphalt material.

Immediately correct excesses and deficiencies by brooming, or by the addition or removal of aggregate, until a uniform texture is achieved. Use hand methods in areas not accessible to power equipment.

Make the first roller pass to seat the aggregate immediately after the aggregate is applied. Operate rollers at a maximum speed of 8 km/h. Do not permit the aggregate to be displaced by pickup or sticking of materials to the tire surface. Ensure that the amount of rolling is sufficient to uniformly and thoroughly bond the aggregate over the full width. Make a minimum of three complete coverages. Ensure that rolling is completed within 1 hour after the asphalt is applied to the surface.

410.10 Fog Seal. To construct a fog seal, apply a slow-setting emulsified asphalt diluted with an equal amount of water onto an existing asphalt surface. Apply the diluted emulsified asphalt in accordance with Subsection 410.08 at a rate of 0.45 to

0.70 L/m2, depending on the condition of the existing surface. Allow the fog seal to penetrate undisturbed for at least 2 hours, or until the emulsified asphalt breaks and is substantially absorbed into the existing surface. Then lightly cover remaining spots of excess asphalt with blotter before opening the surface to traffic.

410.11 Single-Course Surface Treatment. To construct a single-course surface treatment, apply asphalt onto an existing asphalt surface, immediately followed by a single, uniform application of aggregate. Apply the asphalt and aggregate in accor-dance with Subsections 410.08 and 410.09 at the approximate rates shown in table 410-1. Determine the exact application rates based on approved control strips.

Unless the road is closed to all traffic for the duration of the placement of the surface treatment, use a pilot car to limit traffic speeds. During the initial 45 minutes after rolling, limit the traffic speeds to 15 km/h. Limit traffic speeds to 30 km/h for 24 hours. At all times, operate hauling equipment in a prudent manner and at speeds that will not damage the new surface treatment or create a hazard to the traveling public.

Lightly broom the aggregate surface on the morning after construction. Do not displace embedded material.

Maintain the surface for 4 days after the application of the last layer of aggregate by distributing blotter to absorb any free asphalt, by repairing areas deficient in aggregate, and by sweeping excess material from the surface using a rotary power broom. Broom when the air temperature is less than 24 °C. Do not displace embedded material when brooming.

410.12 Multiple-Course Surface Treatment. To construct a multiple-course sur-face treatment, apply multiple layers of asphalt and aggregate. Apply each asphalt and aggregate layer in accordance with Subsections 410.08 and 410.09, and at the approx-imate rates shown in table 410-2 or 410-3. Determine the exact application rates based on approved control strips. When approved by the CO, a steel-wheeled roller with a minimum weight of 8 t may be substituted for one of the pneumatic tire rollers.

Maintain the surface and limit traffic in accordance with Subsection 410.11.

Wait at least 72 hours between application of the layers when using a cutback asphalt, and 24 hours when using an emulsified asphalt. No wait is necessary when using asphalt cement.

410.13 Acceptance. Asphalt cement, emulsified asphalt, and cutback asphalt will be evaluated for acceptance under Subsection 106.05.

Asphalt treatment aggregate and blotter will be evaluated for acceptance under Subsection 105.03.

Provide the minimum number of samples and tests specified in table 410-4, in accordance with Section 160.

Measurement

410.14 Method. Use the method of measurement that is DESIGNATED IN THE

SCHEDULE OF ITEMS.

Water used for diluting emulsified asphalt will not be included in the quantity for PAY ITEM 410(04), and will not be paid for separately.

Payment

410.15 Basis. The accepted quantities will be paid for at the contract unit price for each PAY ITEM DESIGNATED IN THE SCHEDULE OF ITEMS.

Payment will be made under:

Pay Item Pay Unit

410 (01) Surface treatment aggregates, designation ___................... Ton

410 (02) Surface treatment aggregates, designation ___.............Cubic Meter

410 (03) Asphalt cement, grade ___................................................ Ton

410 (04) Emulsified asphalt, grade ___............................................ Ton

410 (05) Cutback asphalt, grade ___................................................ Ton

410 (06) Blotter............................................................................... Ton

410 (07) Blotter.........................................................................Cubic Meter

a. Use in work is permitted prior to sampling and testing for conformance.

b. See Subsection 105.06. Testing not required when using Government-provided material source.

c. An undeveloped source is a source that has not supplied surface treatment aggregate within 365 days of the start of producing surface treatment aggregate for this project.

d. Applies to each aggregate grade furnished.

e. Use only for gravel sources.

S ection 410

Table 410-4—Sampling and testing.

Type of Acceptance Material or Product

Property or Characteristic

Test Method or Specification Frequency Sampling Point

Production certification

Asphalt cement a Contract requirements AASHTO M 20 or

M 226, as applicable Each shipment –

Emulsified asphalt a Subsection 702.03

Cutback asphalt a AASHTO M 81 or

M 82, as applicable Tested conformance Material source b

(Contractor-located source)

Los Angeles abrasion

AASHTO T 96 Three times for each undeveloped source, c or once for all other sources

Material source

Sodium sulfate soundness loss

AASHTO T 104

Durability index (coarse and fine)

AASHTO T 210

Density AASHTO T 19 Coating and stripping of bitumen -aggregate

AASHTO T 182

Asphalt surface treatment aggregate

Gradation , table 703-8 d AASHTO T 27 and T 11

Once for…