Section 405 — Open-Graded Asphalt Friction Course

Description

405.01This work consists of constructing an open- graded asphalt friction course (OGFC).

Material

405.02Conform to the following Subsections: Antistrip additive 702.05 Asphalt binder 702.01 Mineral filler 725.05 Open -graded asphalt friction course aggregate 703.08

Construction Requirements

405.03Composition of Mix (Job- Mix Formula). Provide OGFC mixes of aggregate and asphalt binder designed according to ASTM D7064 or other approved methods that meet the applicable requirements shown in Table 405-1. Fabricate gyratory compacted specimens 6 inches in diameter and 4 inches nominal height. The Cantabro abrasion test is not required. Table 405-1

OGFC Mix Requirements

Design Parameter Requirement

Air voids, ASTM D3203 or D6752 18% minimum Draindown, ASTM D6390 0.3% maximum, by mixture mass

Moisture susceptibility,

AASHTO T 283, except as modified by ASTM D7064 80% minimum

(a)Submittals. Submit a written JMF, mix design reports, applicable charts, application temperature range, and design data for verification at least 30 days before production. Include a signed statement prepared by the testing laboratory that certifies the proposed JMF m eets requirements. For the proposed JMF, submit the following:

(1)Aggregate and mineral filler.

(a)Target values:

(1)Target value for percent passing each specified sieve size for the aggregate blend and

(2)Set target values within the gradation ranges shown in Table 703-4 for the required grading. Allowable deviations are shown in Table 703-2.

(b)Source and percentage of each stockpile to be used;

(c)Average gradation of each stockpile; 370 (d) Representative samples from each stockpile. Use split samples of material taken at the same time samples are taken for testing by the Contractor’s laboratory.

(1)200 pounds of aggregates proportioned by each stockpile according to the JMF and

(2)2 pounds of mineral filler, if proposed for the JMF.

(e)Results of aggregate quality tests performed within 1 year of use.

(2)Asphalt binder. Conform to Subsection 401.03(d)(2) .

(3)Antistrip additives. Conform to Subsection 401.03(d)(3) .

(b)Verification. The verification process starts after required documentation and material are received. Do not start OGFC production until the JMF is verified.

(1)Aggregate gradations. The Contractor’s aggregate gradation is verified if the CO’s gradation on a combined OGFC mix using the Contractor’s aggregate stockpile percentage recommendations is within the Contractor’s target value gradation plus or minus the tolerance shown in Table 405-2. Table 405-2 Aggregate Gradation Verification Tolerances

Sieve Size Tolerance,

Percent (±) No. 4 3.0 No. 8 3.0 No. 200 1.0

(2)Moisture susceptibility. The Contractor’s retained tensile strength result determined by AASHTO T 283, except as modified by ASTM D7064, is verified if the CO’s result is 80 percent minimum.

(c)Changes and resubmissions. If a JMF is rejected or the source of material is changed, submit a new JMF for verification. Up to 14 days may be required to evaluate a change after receipt of required documentation and material. Approved changes in target values will not be applied retroactively for payment. The CO will deduct JMF evaluation costs resulting from the following:

(1)Contractor- requested changes to the approved JMF; and

(2)Additional testing necessary due to the failure of a submitted JMF.

405.04Mixing Plant. Conform to Subsection 401.04.

405.05Pavers. Conform to Subsection 401.05(a).

405.06Surface Preparation. Conform to Subsection 401.06.

405.07Weather Limitations. Place the OGFC mix on a dry asphalt surface when the air temperature in the shade is above 55 °F and the road surface temperature is above 60 °F. Stop placement if either temperature falls below these minimums.

405.08Preparing and Mixing Material. Prepare, mix, and control material according to Subsections 401.08 through 401.10, except do not heat the aggregate introduced into the mixer above the optimum mixing temperature established in the JMF.

405.09Hauling, Placing, and Finishing. Haul, place, and finish the mix accor ding to Subsections 401.11 and 401.13. Place the mix within the approved temperature range. Minimize asphalt binder drainage by discharging the mix into the paver within 1½ hours of loading the truck. If surge bins are used, start this 1½-hour limit at the time the mix is deposited into the su rge bin.

405.10Compacting. Roll the OGFC mix before the mix temperature drops below 200 °F or the temperature recommended by the asphalt binder manufacturer. Use a steel -wheeled roller for compacting the mix. Do not shove, distort, or strip the mix benea th the roller. Roll the mix parallel to the centerline, commencing at the outside edge and progressing towards the center. On superelevated curves, start the rolling on the low side and progress to the high side. Limit rolling to that necessary to consolid ate the OGFC and bond it to the underlying surface.

405.11Joints and Cleanup. Use butt joints for longitudinal and transverse joints. Protect the completed OGFC from traffic until it has sufficiently hardened to resist abrasion, pickup, and raveling. Dispose of material trimmed from the edges and other discarded asphalt concrete mix according to Subsection 203.07.

405.12Straightedge Measurement. Conform to Subsection 403.11.

405.13Acceptance. See Table 405-3 for sampling, testing, and acceptance requirements. Aggregate quality properties will be evaluated under Subsections 106.02 and 106.04. Mineral filler and antistrip additives will be evaluated under Subsections 106.02 and 106.03. Asphalt binder will be evaluated under Subsections 106.03 and 106.04. Asphalt content and aggregate gradation will be evaluated under Subsection 106.05 . Evaluations will consider the following:

(a)Asphalt content. The upper and lower specification limits are the approved JMF target value ±0.4 percent.

(b)Aggregate gradation. The upper and lower specification limits are the approved JMF target values plus or minus the allowable deviations shown in Table 703-2. Construction of open- graded asphalt friction course will be evaluated under Subsections 106.02 and 106.04. 372 Measurement

405.14Measure the S ection 405 pay items listed in the bid schedule according to Subsection 109.02 .

Payment

405.15The accepted quantities will be paid at the contract price per unit of measurement for the Section 405 pay items listed in the bid schedule, except the OGFC contract price will be adjusted according to Subsection 106.05. Payment will be full compensation for the work prescribed in this Section. See Subsection 109.05. Payment for OGFC will be made at a price determined by multiplying the contract price by the m aterial pay factor. The material pay factor is the lowest single pay factor determined for asphalt content or any individual sieve of the aggregate gradation. Table 405-3 Sampling, Testing, and Acceptance Requirements

Material or

Product

(Subsection) Type of

Acceptance

(Subsection) Characteristic Category Test Methods

Specifications Sampling

Frequency Point of

Sampling Split

Sample Reporting

Time Remarks

Source

OGFC

aggregate (703.08 ) Measured & tested for conformance (106.04 & 105) Quality − Subsection

703.081 per type & source of material Source of material Yes Before production Not required if using

Government-

furnished source

Asphalt

binder (702.01 ) " Quality − AASHTO M 320 " Asphalt supplier or mixing plant " " −

Mix Design

OGFC

asphalt concrete mixture Measured & tested for conformance (106.04 ) Gradation − AASHTO T 27 & T 11 1 per submitted mix design Stockpiles Yes 30 days before producing − Air voids − ASTM D3203 or D6752 " − " " − Draindown − ASTM D6390 " − " " −

Tensile

strength ratio − AASHTO T 283 " − " " Complete

AASHTO

T 283, except as modified by

ASTM

D7064 Table 405- 3 (continued) Sampling, Testing, and Acceptance Requirements

Material or

Product

(Subsection) Type of

Acceptance

(Subsection) Characteristic Category Test Methods

Specifications Sampling

Frequency Point of

Sampling Split

Sample Reporting

Time Remarks

Production

OGFC Statistical

(106.05) Asphalt content I AASHTO T 308 1 per 300 tons Point of discharge of the mixing unit Yes 24 hours −

Gradation

(at paver)

AASHTO

T 30 " " " " − No. 4 I No. 200 I

Other specified

sieves II

Measured &

tested for conformance (106.04 ) Placement & compaction temperature − − First load & as directed thereafter Hauling vehicle before dumping, or windrow before pickup and pavement surface during rolling No Upon completion of measurement −

Asphalt

binder (702.01 ) " Quality − Subsection

702.011 per 1000 tons of mix In line between tank & mixing plant Yes, 2 1-quart samples − Test by

Government

Table 405- 3 (continued) Sampling, Testing, and Acceptance Requirements

Material or

Product

(Subsection) Type of

Acceptance

(Subsection) Characteristic Category Test Methods

Specifications Sampling

Frequency Point of

Sampling Split

Sample Reporting

Time Remarks

Production (continued)

OGFC Process

control (153.03) Gradation at plant − AASHTO T 27 & T 11 Contractor determined Cold feed or hot bins as applicable No 24 hours −

Moisture

content of aggregates − AASHTO T 255 " Stockpile " " −

Finished Product

OGFC Measured &

tested for conformance (106.04) Surface tolerance − Straightedge measurements,

Subsection

403.11Continuously, after compaction Finished pavement surface No 24 hours −