420POLYMER MODIFIED OPEN GRADED FRICTION COURSE

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so that a minimum of 80.0 % of the material will pass the No. 8 {2.35 mm} sieve and 25.0 % will pass the No. 60 {0.250 mm} sieve. In addition, a minimum of 5.0 % will pass the No. 200 {75 m} sieve. No more than 10.0 % agricultural limestone shall be used. The aggregate shall be combined into a total blend that will produce an acceptable job mix within the gradation limits shown in the following table. The blend shall be made from at least two stockpiles of different gradations. At least 10% of the blend shall be taken from each stockpile. AGGREGATE GRADATION FOR OPEN GRADED FRICTION COURSE Sieve (Square Mesh Type) Percent Passing By Weight {Mass} 3/4 inch {19.0 mm} 100 1/2 inch {12.5 mm} 85 - 100 3/8 inch {9.5 mm} 55 – 65 No. 4 {4.75 mm} 10 - 25 No. 8 {2.36 mm} 5 - 10 No. 200 {75 m} 2 - 4 As stated in Article 410.02 no RAP or RAS is Allowed.

The liquid binder shall be a polymer modified PG 76-22 meeting the requirements of Section 804. The proportion of liquid asphalt binder to total sample by weight {mass} shall be 6.0 % to 9.0 %. The exact proportion shall be fixed by the job mix formula. Additives or modifiers shall be used to prevent stripping of liquid asphalt binder. These additives or modifiers shall be furnished and used at no additional cost to the State.

The polymer additive shall meet the requirements of Section 811.

A fiber stabilizer or Evotherm 3G meeting the requirements given in Section 410 shall be incorporated into the mix to produce a maximum liquid asphalt binder cement draindown of 0.30 % or less when tested at 325°F {163°C} and 350°F {176°C} in accordance with AASHTO T305. The fiber shall be blended into the mix in accordance with the requirements given in Section 410.

Tack coat materials shall either be a CQS-1hp asphalt emulsion used in conjunction with the spray paver equipment as required in Subarticle 420.04 (d) or “PG Asphalt for Trackless Tack” including DOTC- 10, eTac HB, or Ultrafuse with conventional paving equipment. All tack coat materials shall meet the requirements given in Section 804 except as modified by the requirements given herein. The CQS-1hp shall be smooth and homogeneous and shall meet the requirements shown in the following table: POLYMER MODIFIED OPEN GRADED FRICTION COURSE 229

CQS-1hp MODIFIED ASPHALT EMULSION TEST OF EMULSION Parameter Test Method Value Viscosity @ 77 F, SF AASHTO T 59 20 Min. 150 Max. Sieve Test, % AASHTO T 59 - 0.1 Max.1 24-Hour Storage Stability, % AASHTO T 59 - 1.0 Max. 2 Residue By Distillation AASHTO T 59 60 Min. - Oil Distillate, by Volume of Emulsion, % AASHTO T 59 - - Particle Charge AASHTO T 59 Positive 3 TEST OF RESIDUE FROM EMULSION Solubility in TCE, % AASHTO T 44 4 97.5 Min. - Elastic Recovery @ 50 F AASHTO T 301 60.0 Min. - Penetration @ 77 F AASHTO T 49 60 Min. 110 Max. Ductility @ 77.0 F AASHTO T 51 40 Min. -

but shall be a smooth homogeneous color throughout the sample.

of 6.7 allowable.

The original "PG Asphalt for Trackless Tack" (no RTFO or PAV testing) shall conform to the physical requirements shown in the following table: SPECIFICATIONS FOR PG ASPHALT FOR TRACKLESS TACK Parameter Specification Test Method Rotational Viscosity Maximum 3 Pas @ 135 C AASHTO T 316 Penetration Maximum 25 @ 77 °F {25 °C}, 100 g. 5s AASHTO T49 Softening Point (°C) Minimum 70 AASHTO T 53 Dynamic Shear, G*/sin  Minimum 1.0 kPa @ 82 C AASHTO T 315

420.03Design

The Open Graded Friction Course shall be designed with a minimum air void content of 12% according toALDOT-259, OPEN GRADED ASPHALT CONCRETE FRICTION COURSE DESIGN METHOD. The contractor shall have the responsibility for the design of Section 420 mixes. The laboratory compacted density as determined in the job mix formula design shall not exceed 150 pounds per cubic foot {2400 kg/m 3}; this corresponds with a maximum specific gravity value of 2.837 or a bulk specific gravity of 2.411. The work will be accepted on a LOT by LOT basis in accordance with the applicable requirements. Pay factors for air voids and density shall not apply.

420.04Construction Requirements

The requirements of Articles 410.03 through 410.07 shall apply except as modified hereinafter in this Article.

The rate of application of the tack coat on the asphalt surface shall be 0.13 to 0.18 gallons per square yard within a tolerance of -0.02 and +0.02 gallons per square yard for the PG Asphalt for Trackless Tack. CQS-1hP asphalt emulsion shall be applied at a rate of 0.18 - 0.23 gallons per square yard within a tolerance of -0.02 and +0.02 gallons per square yard. A uniform distribution of tack coat across the mat shall be enforced and streaked tack shots shall not be accepted.

The use of conventional paving equipment shall be allowed when the tack coat material used is “PG Asphalt for Trackless Tack” meeting the requirements given in Subarticle 420.02. "PG Asphalt for Trackless Tack" shall be applied at a temperature of 300 °F to 375 °F, on a clean dry surface. STONE MATRIX ASPHALT (SMA) (FIBER STABILIZED ASPHALT CONCRETE) 230

The requirements given in Article 410.03 shall be applicable to the construction of the open-grade friction course except for the following:  The paving machine shall incorporate a tack distribution system, receiving hopper, feed conveyor, and a variable width, heated, ironing or vibratory type screed.  The tack distribution system shall include metered mechanical pressure sprayer to accurately apply and monitor the rate of application of the emulsion for the tack. The rate shall be uniform across the entire paving width. It shall be applied at a temperature of 140 – 180 °F. Application shall be immediately in front of the screed unit. No wheel or other part of the paving machine shall come in contact with the tack before the paving mix is applied.  Extensions added to the screed shall be provided with the same heating capability as the main screed unit, except for use on variable width tapered areas as approved by the Engineer.

Item 410.03(a)5 is amended to require that steel wheel tandem (7 ton {6 metric ton} minimum size) rollers shall be furnished in sufficient numbers based on the quantity of material being placed to provide effective compaction coverage within the workable time period of the mix as designated by the Engineer. Rubber-tire rollers shall not be used.

The weather, air, and surface temperature limitations for (polymerized) HMA mixes are found in Subarticle 410.03(b).

Subarticle 410.03(g) is amended to require that rolling shall be as approved by the Engineer; no density tests will be required.

420.05Method of Measurement

The accepted quantities of polymer modified open graded friction course will be measured as provided in Article 410.08. The CQS-1hp emulsion or “PG Asphalt for Trackless Tack” for the tack coat will be measured in gallons in accordance with the requirements given in Article 109.02.

420.06Basis of Payment

Polymer Modified Open Graded Friction Course, measured as noted above, will be paid for at the contract unit price bid in accordance with Article 410.09. The unit price of the Open Graded Friction Course Tack Coat shall be full compensation for all materials, equipment, and labor required to furnish and place the tack.

- A Polymer Modified Open Graded Friction Course – per ton {metric ton} - B Open Graded Friction Course Tack Coat – per gallon STONE MATRIX ASPHALT (SMA) (FIBER STABILIZED ASPHALT CONCRETE)

423.01Description

The work covered by this Section shall consist of constructing a hot mix asphalt layer of fiber stabilized stone matrix asphalt pavement on a prepared surface in accordance with these specifications and in conformity with the lines, grades, typical cross section, and the placement rate shown on the plans or as directed. The plant, equipment, and construction requirements for this pavement are specified in Sections 106 and 410, subject to any exceptions herein. All 423 mixes shall be designed and produced in accordance with the requirements given in this Section and ALDOT-395, SMA Mix Design. STONE MATRIX ASPHALT (SMA) (FIBER STABILIZED ASPHALT CONCRETE) 231

423.02Materials

All fine and coarse aggregate furnished shall come from an approved producer who is participating in and meeting the requirements of ALDOT-249, Procedure for Acceptance of Coarse and Fine Aggregates. The producer's name shall be listed in the Department's Materials, Sources, and Devices with Special Acceptance Requirements Manual, List I-1. The Department has established a list of qualified producers of fine and coarse aggregates. Refer to Subarticle 106.01(f) and ALDOT-355 concerning this list.

Coarse aggregate shall be aggregate retained on the No. 4 {4.75 mm} sieve. The virgin coarse aggregate shall be 100% crushed granite, quarried quartzite, limestone, sandstone, slag, or other 100% crushed manufactured stone meeting the requirements given in Section 801.

The maximum amount of flat and elongated particles in coarse aggregate for SMA is given in the following table. PERCENT OF FLAT AND ELONGATED PARTICLES IN COARSE AGGREGATE FOR SMA Test Method Maximum Flat & Elongated % by Count 3:1 (max to min) ASTM D 4791 Section 8.4 20 % Flat & Elongated % by Count 5:1 (max to min) ASTM D 4791 Section 8.4 5 %

The percent degradation of the source aggregate by the sodium sulfate soundness test (AASHTO T 104, Soundness of Aggregate by Use of Sodium Sulfate or Magnesium Sulfate) after five cycles of testing shall not exceed 10 %.

The amount of deleterious substances and absorption in the coarse aggregate shall not exceed the limits given in the following table. DELETERIOUS MATERIALS AND ABSORPTION IN COARSE AGGREGATE FOR SMA Coal and Lignite (Visual) 0.25 % Clay Lumps and Friable Particles (AASHTO T 112) 0.25 % Other local deleterious substances (Shale, Mica, Marcasite, etc.) (Visual) 2.0 % Absorption (Absorption on the material passing the 3/4 inch {19.0 mm} sieve and retained on the No. 4 {4.75 mm} sieve) (AASHTO T 85 *). Applies to gravel aggregates only. 2.0 % * Section 8.1 of AASHTO T 85 modified to require a 15 minute vacuum saturation period as per Section 6.3 of AASHTO T 209 prior to the required 15-19 hour soaking period.

The percent loss of the coarse aggregate by the LA Abrasion test (AASHTO T 96, Resistance to Abrasion of Small Size Aggregate by use of the Los Angeles Machine ) shall not exceed 48 % except that, for Sandstone and Blast Furnace Slag, the LA Abrasion shall not exceed 55 %.

Fine aggregate shall be 100% crushed granite, limestone, sandstone, slag, or other 100% crushed manufactured stone meeting the requirements of Section 802 and the following table. The parent material shall meet the requirements given in Section 801. STONE MATRIX ASPHALT (SMA) (FIBER STABILIZED ASPHALT CONCRETE) 232

FINE AGGREGATE QUALITY REQUIREMENTS FOR SMA Test Method Minimum Maximum Uncompacted Voids %, AASHTO T 304* 45 % 100 % Sand Equivalent %, AASHTO T 176* 50 % 100 % Liquid Limit %, AASHTO T 89 0 % 25 % Plasticity Index, AASHTO T 90 Non-plastic *The Sand Equivalent and Uncompacted Voids may be run on the blend of the aggregates.

The fine aggregate shall be non-plastic when tested in accordance with AASHTO T 89, as modified by ALDOT-232, and AASHTO T 90 and shall have a maximum of 1.0 % clay lumps and friable particles as determined by AASHTO T 112. It shall consist of hard, tough grain, free of injurious amounts of clay, loam, or other deleterious substances.

The mineral filler shall meet the requirements of Section 805.

The requirements for allowing the use of RAP and RAS are given in Article 410.02.

The combined aggregates shall conform to the percent passing by volume requirements given in the following table. PERCENT PASSING BY VOLUME OF AGGREGATE FOR SMA Sieve Size 1.5 inch {37.5 mm} Maximum Aggregate Size 1 inch {25.0 mm} Maximum Aggregate Size 3/4 inch {19.0 mm} Maximum Aggregate Size 1/2 inch {12.5 mm} Maximum Aggregate Size 3/8 inch {9.5 mm} Maximum Aggregate Size Lower Limit Upper Limit Lower Limit Upper Limit Lower Limit Upper Limit Lower Limit Upper Limit Lower Limit Upper Limit 1.5 inch {37.5 mm} 100 100 1 inch {25.0 mm} 90 100 100 100 3/4 inch {19.0 mm} 30 86 90 100 100 100 1/2 inch {12.5 mm} 26 63 50 74 90 100 100 100 3/8 inch {9.5 mm} 24 52 25 60 26 78 90 100 100 100 # 4 {4.75 mm} 20 28 20 28 20 28 26 60 90 100 # 8 {2.36 mm} 16 24 16 24 16 24 20 28 28 65 # 200 {75 m} 6 10 6 10 6 10 6 10 12 15 An example of how to blend aggregate based upon volume can be found in ALDOT-395, SMA Mix Design. The production tolerances for the above gradation bands are as specified in Item 410.02(d)7, except that the tolerance for the No. 4 {4.75 mm} sieve is +/- 4% and for the 3/8 inch {9.5 mm} sieve is +/- 6%. Aggregates that tend to polish under traffic, such as limestone, dolomite, or marble, shall be permitted only in widening as defined by Article 410.01, shoulder paving, underlying layers, and layers that are to be covered by Polymer Modified Open Graded Friction Course (Section 420) mix in this contract, except as noted in the following table. STONE MATRIX ASPHALT (SMA) (FIBER STABILIZED ASPHALT CONCRETE) 233

ALLOWABLE CARBONATE STONE CRITERIA FOR SMA BPN 9 Value Of Aggregate Source * Maximum Allowable Percentage Of Carbonate Stone ≤ 20 Not Allowed 21 through25 30 26 through 28 35 29 through 31 40 32 through 34 45  35 50 * This value, BPN 9, is made using the British Pendulum Tester on aggregate source specimen polished for 9 hours on an accelerated polishing machine known as the British Wheel as per ASTM D 3319, ASTM E 303 and BMTP-382.

In no case shall the total amount of virgin carbonate stone in the combined mixture used as actual wearing surface layers exceed the percentage shown in the table above. When parts of the carbonate stone used in the mix are from differing strata of material or coming from multiple sources that are represented by different BPN 9 values, the lowest BPN 9 value will be used.

Unless otherwise shown on the plans, for pavement layers in the top 2 inches the liquid asphalt binder shall meet the requirements of Section 804 and shall be polymer-modified to meet a PG 76-22 as given in Section 811. For pavement layers below the top 2 inches the liquid asphalt binder shall be PG 67-22 and shall meet the requirements of Section 804. If Open Graded Friction Course (Section 420) layers are required, the top 2 inches shall be measured from the bottom of the Open Graded Friction Course layer.

The minimum liquid asphalt binder content shall be as given in the following table (by weight {mass} of total mix.

MINIMUM LIQUID ASPHALT BINDER CONTENT FOR SMA Maximum Aggregate Size (inches) {mm} Nominal Aggregate Size

Minimum Liquid Asphalt Binder Content (% by weight) {% by mass} Minimum Liquid Asphalt Binder Content for mixes containing RAS (% by weight) {% by mass}

1.5 {37.5} 1.0 {25} 5.3 5.5 1.0 {25.0} 3/4 {19.0} 5.5 5.7 3/4 {19.0} 1/2 {12.5} 5.7 5.9 1/2 {12.5} 3/8 {9.5} 5.9 6.1 3/8 {9.5} No. 4 {4.75} 6.1 6.3

A fiber stabilizer meeting the requirements given in Section 410 shall be incorporated into the mix to reduce draindown. The fiber shall be blended into the mix in accordance with the requirements given in Section 410. RAS may be allowed as a fiber stabilizer provided it meets the requirements in Section 410.

423.03Design

All SMA mixes shall be designed according to ALDOT-395, SMA Mix Design. SMA mixes shall be designed using a 50 blow Marshall design or a 50 gyration gyratory compactor design. The SMA shall have a minimum VMA of 17, a VCA MIX less than the VCA DRC (calculating Voids in the Coarse Aggregate is explained in ALDOT-395 SMA Mix Design) and air voids of 3.5% for SMA mixes containing RAS or 4.0 % for all other SMA mixes. The SMA mix shall be designed with a minimum tensile strength ratio of 0.80 according to ALDOT-361. All SMA mixes shall be tested for susceptibility to rutting in accordance with the latest approved version of AASHTO T 324 Hamburg Wheel-Track Testing of Compacted Asphalt Mixtures. All Mixes shall be tested at 50°C. SMA mixes using PG 67-22 binder shall exhibit 10 mm rutting STONE MATRIX ASPHALT (SMA) (FIBER STABILIZED ASPHALT CONCRETE) 234

or less at 10,000 cycles. SMA mixes using PG 76-22 binder shall exhibit 10 mm rutting or less at 20,000 cycles.

423.04Hot Mix Asphalt Plant Requirements

To ensure accurate metering and proportioning, the introduction of the mineral filler shall be in accordance with Section 4.3 of AASHTO M 156 as specified in ALDOT-324. Adequate dry storage shall be provided for the mineral filler. In a batch plant, mineral filler shall be added directly into the weigh hopper. In a drum plant, mineral filler shall be added directly into the drum mixer near enough to the liquid asphalt binder line so that the mineral filler is captured by the liquid asphalt binder. Note: For most SMA projects, the flow rate of the mineral filler governs the plant production rate.

SMA shall be stored according to the requirements as given in ALDOT 324, “Plant Requirements for Plants Producing Hot-Mixed, Hot-Laid Asphalt Mixtures”. SMA shall not be heated above 350 °F {177 °C} without the approval of the Engineer.

423.05Construction Requirements

Construction requirements shall be the same as specified in Articles 410.03 through 410.07 except as noted in this Article.

The weather, air and surface temperature limitations for (polymerized) HMA mixes are found in Subarticle 410.03(b).

A thin tack coat meeting the requirements of Section 405 shall be applied to ensure uniform and complete adherence of the overlay.

Due to the nature of stone matrix asphalt mixture, the surface shall be rolled immediately. Rollers shall move at a uniform speed, not to exceed 3 miles per hour {5 km/hr}, with the drive roller nearest the paver. Rolling shall be continued until all roller marks are eliminated and the required density has been obtained. The Contractor shall monitor density during the compaction process using the nondestructive testing devices approved in Section 306 of the Specifications to ensure that the required density is being obtained. The device shall either be calibrated to roadway cores or gage counts and shall be used to determine the rolling pattern producing maximum density. If vibratory compaction causes aggregate breakdown or forces liquid asphalt binder to the surface, the vibratory mode shall be turned off and the roller shall operate in static mode only. To prevent adhesion of the mixture to the rollers, it shall be necessary to keep the rollers properly moistened with water mixed with very small quantities of detergent or other approved material.

423.06Method of Measurement

The accepted quantities of stone matrix asphalt binder layer and stone matrix asphalt wearing layer will be measured as provided in Article 410.08. The SMA mix shall be evaluated for liquid asphalt binder content, laboratory compacted air voids, and in-place density; pay factors will be applied.

423.07Basis of Payment

Stone Matrix Asphalt Binder Layer and Stone Matrix Asphalt Wearing Layer, measured as noted above, will be paid for at the contract unit price bid in accordance with Article 410.09.

423-A Stone Matrix Asphalt Wearing Layer, * Maximum Aggregate Size - per ton {metric ton} 423-B Stone Matrix Asphalt Binder Layer, * Maximum Aggregate Size - per ton {metric ton} * Specify Maximum Aggregate Size, either 1.5, 1, 3/4, 1/2 or 3/8 inches {37.5 mm, 25 mm, 19 mm, 12.5 mm, or 9.5 mm}