442Superpave Asphalt Concrete

442.01 Description. This work consists of design, production, placement, compaction and

testing of one or more courses of Superpave asphalt concrete, on a prepared foundation. The Superpave asphalt concrete consists of a mixture of graded aggregate and specified type and grade of asphalt binder that is designed using Superpave mix design procedures and a gyratory compactor. The aggregate and asphalt binder are mixed in a central plant then spread and compacted on the prepared surface. The requirements of Items 401, 402, 403, and 440 apply with the additional requirements of this specification.

442.02 Type A Mix Design.

Supply aggregate according to the lane current average daily truck traffic (Lane ADTT) as follows unless otherwise shown on the plans: Lane ADTT = Current ADT × T24 × 0.45 Where: Current ADT = current average daily traffic count from the plans T24 = percent trucks per day from the plans TABLE 442.02-1 GYRATION LEVEL AND MATERIAL REQUIREMENTS Lane ADTT Nini Ndes Nmax Coarse Aggregate Angularity Fine Aggregate Angularity Flat and Elongated Particles Sand Equivalent <4000 7 65 105 95 [1] /90 [2] 44 10 45 ≥4000 7 65 105 100 [1] /100 [2] 44 10 50 [1] Percent fractured (one or more faces) according to ASTM D5821 [2] Percent fractured (two or more faces) according to ASTM D5821 Submit aggregate to be used to OMM for approval a minimum of 3 weeks before submitting a JMF for approval. If fine aggregate is from crushed carbonate stone or air -cooled blast furnace slag, the Department will not require the fine aggregate angularity (FAA) test. The Department will allow a blend of a material not meeting the FAA with a material that meets the FAA, but calculate the FAA result based on the individual Department FAA results and actual blend percentages. Obtain OMM approval of any blends. The restricted zone does not apply. Use control points according to MS -2, except as specified in Table 442.02-2. TABLE 442.02-2 AGGREGATE GRADATION REQUIREMENTS Sieve Size 9.5 mm mix 12.5 mm Surface Course Mix 12.5 mm Intermediate Course Mix 19 mm mix Total Percent Passing 1 1/2 inch (37.5 mm) – – 100 100 3/4 inch (19 mm) – 100 95 to 100 85 to 100 1/2 inch (12.5 mm) 100 95 to 100 90 to 100 90 max 3/8 inch (9.5 mm) 90 to 100 96 max 89 max – No. 4 (4.75 mm) 70 max 52 to 60[1] 60 max – No. 8 (2.36 mm) 34 to 52 34 to 45 34 to 45 28 to 45 No. 200 (75 µm) 2 to 8 2 to 8 2 to 8 2 to 6 [1] For the No. 4 sieve do not exceed 63 in production. Ensure that the F/A ratio is a maximum of 1.2. Use a 2-hour cure for the mix design. If more than 15 percent fine aggregate not meeting FAA is used, perform testing using the asphalt pavement analyzer (APA) according to Supplement 1057. To estimate an APA sample mix volume, use the bulk density from gyratory specimens at Ndes. Deformation less than 0.20 inch (5.0 mm) at 120 F (48.9 C) are considered passing for PG 58-28 and PG 64-22 mixes. Deformation less than 0.12 inch (3.0 mm) at 130 F (54.4 C) are considered passing for all other mixes. Test design volumetric properties at Ndes. Test Nmax for the required criteria. Ensure that the VMA is not less than the minimum values of Table 442.02-3. TABLE 442.02-3 VMA CRITERIA Mix VMA (percent minimum) 9.5 mm 15.0 12.5 mm Surface 14.0 12.5 mm Intermediate 14.0 19.0 mm 13.0 Perform the IDEAL-CT on all mixes and report results according to Supplement 1033.

442.03 Type B Mix Design. Apply the mix design specified in 442.02 for a Type A mix except

as modified by this subsection: Modify the Coarse Aggregate Angularity of Table 442.02-1 according to Table 442.03-1. TABLE 442.03-1 COARSE AGGREGATE ANGULARITY Lane ADTT Coarse Aggregate Angularity <4000 65 [1] /65 [2] ≥4000 75 [1] /70 [2] [1] Percent fractured (one or more faces) according to ASTM D5821 [2] Percent fractured (two or more faces) according to ASTM D5821 Ensure that at least 50 percent by weight of virgin fine aggregate is aggregate meeting FAA or is crushed carbonate stone or air-cooled blast furnace slag. Modify the No. 8 (2.36 mm) sieve requirement for a 12.5 mm surface course mix in Table 442.02-2 to 34 to 40 percent. Apply an F -T value of +2 according to 440.04 and 403.06.

442.04 Asphalt Binder. Use a PG 70 -22M asphalt binder for surface courses and a PG 64 -28

asphalt binder for 19.0 mm intermediate courses. For 12.5 mm intermediate courses use a PG 64 -22 asphalt binder for 25 percent or less RAP, and a PG 64-28 asphalt binder for more than 25 percent RAP or if RAS is used with or without RAP. The minimum total asphalt binder content for a surface course is 5.8 percent. For 12.5 mm intermediate courses, the minimum total asphalt binder content is 5.4 percent and the minimum total virgin asphalt binder content is 3.5 percent. The minimum total a sphalt binder content for a 19.0 mm is 4.6 percent.

442.05 Acceptance. The Department will base acceptance of the asphalt concrete mix on the

method specified in the Contract line item description (i.e., 446, 447, 448, 449).

442.06 Basis of Payment . Include the cost of asphalt material to coat vertical faces and seal

joints and gutters in the contract unit price for Item 442. The Department will pay for accepted quantities at the contract prices as follows: Item Unit Description 442 Cubic Yard Asphalt Concrete Surface Course, (Cubic Meter) (____mm), Type ____ (___) 442 Cubic Yard Asphalt Concrete Intermediate Course, (Cubic Meter) (____ mm), Type ___ (___) 442 Cubic Yard Anti-Segregation Equipment (Cubic Meter)

Superpave Asphalt Concrete in other states

• Florida 334 · SUPERPAVE ASPHALT CONCRETE