6-37 1. 2.36 mm
2.0.075 mm Sieves
b.Binder Content, %, P b
650-7 Measurement and Payment
Open -Graded Asphalt Friction Course, Type FC -1 Modified will be measured and paid as the actual number of tons of friction course incorporated into the completed and accepted work. The friction course will be measured by being weighed in trucks on certified platform scales or other certified weighing devices. Furnishing asphalt binder for the mix will be paid as provided in Article 620- 4 for Asphalt Binder for Plant Mix . Adjustments in contract unit price due to asphalt binder price fluctuation will be made in accordance with Section 620. No direct payment wi ll be made for providing and using the materials transfer vehicle or any associated equipment, as the cost of providing same shall be included in the contract unit bid price per ton for the mix type to be placed. Payment will be made under: Pay Item Pay U nit Open -Graded Asphalt Friction Course, Type FC -1 Modified Ton PERMEABLE ASPHALT DRAINAGE COURSE , TYPES P -78M AND P -57
652-1 Description
Perform the work covered by this section including , but not limited to , the construction of a plant mixed permeable asphalt drainage course (PADC) properly laid upon a prepared surface in accordance with these s pecifications and in conformity with the lines, grades, thickness and typical sections shown on the plans; producing, weighing, transporting, placing and rolling the plant mix as specified in Section 610; furnishing the asphalt binder, anti -strip additive and all other materials for the plant mix; furnishing and applying tack c oat as specified in Section 605; furnishing scales; providing QC as specified in Section 609 as modified for PADC; making any repairs or corrections to the friction course that may become necessary; and maintaining the friction course until final acceptance of the project.
652-2 Materials
Refer to Division 10. Item Section Anti-strip Additives 1020 -8 Asphalt Binder 1020 -2 Coarse Aggregate 1012 -1(B) Fine Aggregate 1012 -1(C) The coarse aggregate shall meet Article 1012 -1 except that that portion of the coarse aggregate retained on the No. 4 sieve shall contain at least 60 % by weight of crushed pieces having two or more mechanically induced fractured faces.
652-3 Composition of Mixture
A.General Formulate the PADC from a mixture of crushed aggregate, asphalt binder, anti -strip additive and other additives as required to produce a mix meeting Table 652 -1.
6-38 At least 10 days before start of asphalt mix production, submit the mix design and
proposed JMF targets for each required mix type and combination of aggregates to the Engineer for review and approval. The JMF will be established in accordance with
Article 610 — 3. Establish the asphalt binder content at the midpoint of the range specified
in Table 652- 1 or as approved by the Engineer .
B.Mix Design Design PADC mixtures conforming to the gradation requirements and other mix design criteria in Table 652 -1 for the mix type spe cified. Use the asphalt binder grade shown in Table 652 -1 for the mix type specified or as approved by the Engineer . Use an anti -strip additive in all PA DC mixes. It may be hydrated lime or a chemical additive or both. Add chemical anti -strip additive at a rate of 0.5% by weight of asphalt binder. Add hydrated lime at a rate of 1.0% by weight of dry aggregate. Use an approved source and grade. The mixing temperature at the asp halt plant will be established on the JMF . The JMF mix temperature shall be within the ranges shown in Table 652- 1 unless otherwise approved by the Engineer . TABLE 652-1 PERMEABLE ASPHALT DRAINAGE COURSE GRADATION AND MIX DESIGN CRITERIA Sieve Size (mm) Total Percent Passing Type P -78M Type P -57 37.5 - 100 25.0 - 95 - 100 19.0 100 - 12.5 95 - 100 25 - 9.50 75 - 100 - 4.75 20 - 45 10 - 2.36 3 - 15 5 - 0.075 1.0 - 3.0 1.0 - 3.0 Asphalt Binder Content, % 2.5 - 3.5 2.0 - 3.0 Asphalt Binder Grade PG 64 -22 PG 64 -22 Mixing Temperature at Plant 240 - 270°F 260 - 290°F
652-4 Construction Methods
Produce, transport to the site and place the asphalt plant mix in accordance with Section 610, except as otherwise provided herein . Incorporate the a sphalt binder into the asphalt plant mix in accordance with Section 620. Add the anti- strip additive to the asphalt binder in accordance with Article 620 -3. A prime coat or tack coat will not be required. When the PADC is placed in trench sections, the rolling equipment and rolling sequences required by Article 610- 9 will not apply.
Source: North Carolina Standard Specifications for Roads and Structures, 2024 Edition. Pages 293–294 of 857.