423STONE 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} SUPERPAVE BITUMINOUS CONCRETE BASE, BINDER, AND WEARING SURFACE LAYERS 235

SUPERPAVE BITUMINOUS CONCRETE BASE, BINDER, AND WEARING SURFACE LAYERS

424.01Description

The work covered by this Section shall consist of a hot or warm bituminous plant mixed pavement layer placed on a prepared surface in accordance with these specifications and in reasonably close conformity with the lines, grades, typical cross section, and placement rate shown on the plans or as directed by the Engineer. The Contractor may use either hot mix or warm mix for all Superpave ESAL Range mixes in Section 424. General requirements for all bituminous concrete pavements as specified in Section 410 are applicable to this Section, subject to any exceptions contained herein. Quality Control/Quality Assurance (QC/QA) requirements as specified in Section 106 are applicable to this section, subject to any exceptions contained herein. The work will be accepted on a LOT by LOT basis in accordance with the applicable requirements.

424.02Materials

The materials furnished for use shall conform to the requirements of Section 410 and the following:

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. Coarse aggregate shall consist of crushed (or uncrushed) gravel with a bulk specific gravity greater than 2.550 (AASHTO T 85), crushed stone, or crushed slag, or a combination thereof having hard, strong, durable pieces, free from adherent coatings, and meeting all requirements of these specifications.

The maximum amount of flat and elongated particles in coarse aggregate for Superpave is given in the following table. PERCENT OF FLAT AND ELONGATED PARTICLES IN COARSE AGGREGATE FOR SUPERPAVE Test Method Maximum Flat & Elongated % by Count 5:1 (max to min) ASTM D 4791 Section 8.4 10 % * * Shall not apply to the 3/8 inch {9.5 mm} mix or to ESAL Range A/B

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 following limits: SUPERPAVE BITUMINOUS CONCRETE BASE, BINDER, AND WEARING SURFACE LAYERS 236

RESTRICTION OF DELETERIOUS MATERIALS AND ABSORPTION IN COARSE AGGREGATE FOR SUPERPAVE 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 aggregate passing the No. 4 {4.75 mm} sieve. Gravel used to manufacture fine aggregate shall have a bulk specific gravity greater than 2.550 (AASHTO T 85). 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 amount of clay material, as indicated by the sand equivalent, measured on the aggregate passing the No. 4 {4.75 mm} sieve as determined by AASHTO T 176, Plastic Fines in Graded Aggregates and Soils by Use of the Sand Equivalent Test, shall be no less than the values defined in the following table according to the total design traffic in equivalent single axle loads (ESALs). CLAY CONTENT CRITERIA FOR SUPERPAVE ESAL Range Traffic (ESALs) Sand Equivalent A/B ESALs < 1.0x106 > 40.0 C/D 1.0x106 < ESALs < 1.0x107 > 45.0 E 1.0x107 < ESALs < 3.0x107 > 45.0

Mineral filler shall consist of finely divided mineral matter such as rock dust, slag dust, hydrated lime, hydraulic cement, or fly ash meeting the requirements of Section 805. The introduction of mineral filler shall be in accordance with AASHTO M 156, Section 3.3, as specified in ALDOT-324, with the additional requirement that accurate proportioning shall be accomplished by means of pneumatic or mechanical metering.

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

The coarse and fine aggregates, mineral filler, and recycled material shall be combined in a total blend that will produce an acceptable job mix within the gradation limits determined by the maximum and minimum control points as shown in the following tables. Maximum particle size is defined as the sieve size that is two sizes larger than the first sieve to retain more than 10 % of the material. The sequence of sieve sizes to be used in determining maximum particle size is given in the following tables. Gradation charts illustrating gradation requirements are given in Article

424.03

The required mix will be shown on the plans. All ALDOT-424 ESAL range “E” Wearing Surface Layer and Upper Binder Layer 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 in water. ALDOT 424 ESAL Range E mixes using PG 67- 22 binder shall exhibit 10 mm rutting or less at 10,000 cycles. ALDOT 424 ESAL Range E mixes using PG 76-22 binder shall exhibit 10 mm rutting or less at 20,000 cycles. SUPERPAVE BITUMINOUS CONCRETE BASE, BINDER, AND WEARING SURFACE LAYERS 237

AGGREGATE GRADATION CONTROL POINTS FOR SUPERPAVE 1 1/2 inch {37.5 mm} Maximum Aggregate Size Mix Control Point (Percent Passing) Sieve Size Minimum Maximum No. 200 {75 m} 1 7 No. 8 {2.36 mm} 19 45 3/4" {19 mm} 19 90 1" {25 mm} Nominal 90 100 1.5" {37.5 mm} Maximum 100 -

AGGREGATE GRADATION CONTROL POINTS FOR SUPERPAVE 1 inch {25.0 mm} Maximum Aggregate Size Mix Control Point (Percent Passing) Sieve Size Minimum Maximum No. 200 {75 m} 2 8 No. 8 {2.36 mm} 23 49 1/2" {12.5 mm} 23 90 3/4" {19 mm} Nominal 90 100 1" {25 mm} Maximum 100 -

AGGREGATE GRADATION CONTROL POINTS FOR SUPERPAVE 3/4 inch {19.0 mm} Maximum Aggregate Size Mix Control Point (Percent Passing) Sieve Size Minimum Maximum No. 200 {75 m} 2 10 No. 8 {2.36 mm} 28 58 3/8" {9.5 mm} 28 90 1/2" {12.5 mm} Nominal 90 100 3/4" {19.0 mm} Maximum 100 -

AGGREGATE GRADATION CONTROL POINTS FOR SUPERPAVE 1/2 inch {12.5 mm} Maximum Aggregate Size Mix Control Point (Percent Passing) Sieve Size Minimum Maximum No. 200 {75 m} 2 10 No. 8 {2.36 mm} 32 67 No. 4 {4.75 mm} 32 90 3/8" {9.5 mm} Nominal 90 100 1/2" {12.5 mm} Maximum 100 -

AGGREGATE GRADATION CONTROL POINTS FOR SUPERPAVE 3/8 inch {9.5 mm} Maximum Aggregate Size Mix Control Point (Percent Passing) Sieve Size Minimum Maximum No. 200 {75 m} 6 12 No. 16 {1.18 mm} 30 60 No. 4 {4.75 mm} Nominal 75 100 3/8" {9.5 mm} Maximum 95 100 Note: Up to 5% may be retained on the maximum size sieve (3/8 inch {9.5 mm}) and up to 25% may be retained on the nominal size sieve (#4 {4.75 mm}).

The coarse aggregate angularity shall be measured on the total blended aggregate retained on the No. 4 {4.75 mm} sieve in accordance with ASTM D 5821. SUPERPAVE BITUMINOUS CONCRETE BASE, BINDER, AND WEARING SURFACE LAYERS 238

A fractured face is defined as an angular, rough, or broken surface of an aggregate particle created by crushing, by other artificial means, or by nature. A face is considered fractured only if it has a projected area at least as large as one-quarter of the maximum projected area (maximum cross-sectional area) of the particle and has sharp, well-defined edges. The percent by weight {mass} of the coarse particles of the blended aggregate retained on the No. 4 {4.75 mm} sieve with one fractured face and with two or more fractured faces shall be no less than the values in the following table. COARSE AGGREGATE ANGULARITY REQUIREMENTS FOR SUPERPAVE ESAL Range Traffic (ESALs) Wearing Surface & Binder Layers Base Layers A/B ESALs < 1.0x106 75 / - 50 / - C/D 1.0x106 < ESALs < 1.0x107 85 / 80 60 / - E 1.0x107 < ESALs < 3.0x107 95 / 90 80 / 75 Note: "85 / 80" denotes that 85 % of the coarse aggregate has at least one fractured face and 80 % has two or more fractured faces.

The percent air voids in loosely compacted fine aggregate, measured according to AASHTO T 304, Method "A", or ASTM C 1252, Method "A", Uncompacted Void Content of Fine Aggregate (as Influenced by Particle Shape, Surface Texture, and Grading) shall be no less than the values in the following table. FINE AGGREGATE ANGULARITY REQUIREMENTS FOR SUPERPAVE ESAL Range Traffic (ESALs) Minimum % Air Void Base Binder & Surface A/B ESALs < 1.0x106 43 43 C/D 1.0x106 < ESALs < 1.0x107 43 45 E 1.0x107 < ESALs < 3.0x107 43 45

The restrictions for the use of carbonate stone are given in the following table. These restrictions do not apply to widening as defined in 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. CRITERIA FOR THE USE OF CARBONATE STONE IN SUPERPAVE 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 ALDOT-382.

In no case shall the total amount of virgin carbonate stone in the combined mixture used as actual wearing surface layers that are exposed to traffic exceed the percentage shown in the above table. 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.

Liquid asphalt binders shall come from an approved producer who is participating in and meeting the requirements of ALDOT-243, Acceptance Program For Asphalt Materials. The producer’s name shall be listed in the Department’s Materials, Sources, and Devices With Special Acceptance Requirements Manual, List I-4. The Department has established a list of qualified producers of asphalt materials. SUPERPAVE BITUMINOUS CONCRETE BASE, BINDER, AND WEARING SURFACE LAYERS 239

Refer to Subarticle 106.01(f) and ALDOT-355 concerning this list. Unless shown otherwise on the plans or in the proposal, liquid asphalt binder for use in all mixes shall meet the requirements of AASHTO M 320, Standard Specification For Performance Graded Asphalt Binder, as modified by the requirements given in the following table and Section 804.

ALLOWABLE ASPHALT BINDER GRADES FOR SUPERPAVE ESAL Range Traffic (ESALs) Base, Lower, & Upper Binder Layers Wearing Surface Layers A/B ESALs < 1.0x106 PG 67-22 PG 67-22 C/D 1.0x106 < ESALs < 1.0x107 PG 67-22 PG 67-22 E 1.0x107 < ESALs < 3.0x107 PG 67-22 PG 76-22* *The asphalt binder shall be PG 76-22 for leveling when the top of the leveling is within 2 inches {50 mm} of the final pavement surface. The asphalt binder may be PG 67-22 for leveling that is not within 2 inches {50 mm} of the final pavement surface and for all patching and widening;. If Open Graded Friction Course (Section 420) layers are required, the final pavement surface shall be the surface of the layer below these layers.

Asphalt Binders shall meet the requirements of Section 804. Polymer modifiers shall be blended at an approved refinery and meet the requirements of Section 811. Approved Warm Mix additives or processes are given in List II-27, “Warm Mix Asphalt Products and Processes” of the Materials, Sources, and Devices with Special Acceptance Requirements manual.

The design air voids for all levels of traffic is 3.5 % for mixes containing RAS and 4.0 % for all other mixes.

The job mix shall be designed at a minimum VMA given in the following table.

VOIDS IN MINERAL AGGREGATE DESIGN VMA FOR SUPERPAVE *** Maximum Aggregate Size *

Nominal Aggregate Size

Minimum VMA (%) 3/8 {9.5 } No. 4 {4.75} 16.5 ** 1/2 {12.5 } 3/8 {9.5} 15.5 3/4 {19.0 } 1/2 {12.5} 14.5 1 {25.0 } 3/4 {19.0} 13.5 1.5 {37.5 } 1 {25.0} 12.5 * As defined in Subarticle 424.02(c) ** All 3/8" (9.5 mm} mixes where the ESAL range is greater than A/B shall have a maximum VMA of 18.0. *** Production VMA may be 0.5 lower than the Minimum VMA given above.

The job mix shall be designed at a minimum Liquid Asphalt Binder Content (Pb) given in the following table. Production tolerances shall be governed by the pay factors in Table III, Section

410.08

SUPERPAVE BITUMINOUS CONCRETE BASE, BINDER, AND WEARING SURFACE LAYERS 240

LIQUID ASPHALT BINDER CONTENT (Pb) CRITERIA FOR SUPERPAVE Maximum Aggregate Size*

Nominal Aggregate Size

Minimum Liquid Asphalt Binder Content

Total Mix** Minimum Liquid Asphalt Binder Content

containing RAS by Percent of Total Mix** 3/8 {9.5 } No. 4 {4.75} 5.90 6.1 1/2 {12.5 } 3/8 {9.5} 5.50 5.7 3/4 {19.0 } 1/2 {12.5} 5.10 5.3 1 {25.0 } 3/4 {19.0} 4.40 4.6 1.5 {37.5 } 1 {25.0} 4.20 4.4 * As defined in Subarticle 424.02(d) ** Nd = 60

The ratio of the percent by weight {mass} of aggregate passing the No. 200 {75 µm} sieve to the effective asphalt content expressed as percent by weight {mass} of the total mix shall be between 0.60 and 1.4. All 3/8 inch {9.5 mm} mixes shall have a dust to effective asphalt ratio range of 0.90 to 2.00. These ratio limits apply to both the design and production phases. Effective asphalt content is that liquid asphalt binder not absorbed into the aggregate pore structure and is determined in accordance with Section 4.09 of the Asphalt Institute's, MS-2, Mix Design Methods for Asphalt Concrete.

A fiber stabilizer meeting the requirements given in Section 410 may 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.

All mixes shall be designed and produced to have a tensile strength ratio (TSR) of at least 0.80 when compacted according to ALDOT-384 at 7.0 % air voids and tested in accordance with AASHTO T 283 as modified by ALDOT-361, except the specimen shall be 6.00" {150 mm} in diameter and 3.75" {95 mm} in height.

All Superpave mixes shall be designed in accordance with ALDOT-384, Superpave Mix Design Procedure for Asphalt Mixtures . All Superpave Gyratory Compactors shall have their angle of gyration verified by the Engineer following the procedure in AASHTO T 344, Standard Method of Test for Evaluation of Superpave Gyratory Compactor (SGC) Internal Angle of Gyration Using Simulated Loading. This includes all design, quality control, and quality assurance SGCs. The compactors shall tilt the specimen molds at an average internal angle of 20.2 ± 0.35 mrad (1.16± 0.02 degrees).

SUPERPAVE BITUMINOUS CONCRETE BASE, BINDER, AND WEARING SURFACE LAYERS 241

Gradation Requirements

50 60 70 80 90 100 PERCENT PASSING GRADATION CHART FOR 1 1/2 inch {37.5 mm} MAXIMUM SIZE AGGREGATE Maximum Density Line 75 150 300 600 1.18um 2.36 4.75 9.5mm 12.5 19.0 25.0 37.5 500 Maximum Control Points Minimum Control Points 0 200 100 50 30 16 8 4 3/8 1/2 3/4 1 1 1/2 2No. In. Sieve Size to the 0.45 Power 50 60 70 80 90 100 PERCENT PASSING GRADATION CHART FOR 1 inch {25 mm} MAXIMUM SIZE AGGREGATE Maximum Density Line 75 150 300 600 1.18um 2.36 4.75 9.5mm 12.5 19.0 25.0 37.5 500 Maximum Control Points Minimum Control Points 0 200 100 50 30 16 8 4 3/8 1/2 3/4 1 1 1/2 2No. In. Sieve Size to the 0.45 Power SUPERPAVE BITUMINOUS CONCRETE BASE, BINDER, AND WEARING SURFACE LAYERS 242

50 60 70 80 90 100 PERCENT PASSING GRADATION CHART FOR 3/4 inch {19 mm} MAXIMUM SIZE AGGREGATE Maximum Density Line 75 150 300 600 1.18um 2.36 4.75 9.5mm 12.5 19.0 25.0 37.5 500 Maximum Control Points Minimum Control Points 0 200 100 50 30 16 8 4 3/8 1/2 3/4 1 1 1/2 2No. In. Sieve Size to the 0.45 Power 50 60 70 80 90 100 PERCENT PASSING GRADATION CHART FOR 1/2 inch {12.5 mm} MAXIMUM SIZE AGGREGATE Maximum Density Line 75 150 300 600 1.18um 2.36 4.75 9.5mm 12.5 19.0 25.0 37.5 500 Maximum Control Points Minimum Control Points 0 200 100 50 30 16 8 4 3/8 1/2 3/4 1 1 1/2 2No. In. Sieve Size to the 0.45 Power