440Asphalt Concrete Mix Design — General

440.01 Description . This specification describes the general requirements for asphalt concrete

pavement mix design for base, intermediate, and surface courses. Provide laboratory and personnel meeting the requirements of Supplement 1041 to perform mix designs. Do not start mix production without a preliminary JMF approval and 48 hour notification of District Testing. Final approval of a JMF will be based on field verification. Obtain a new JMF for any desired change to an existing JMF in excess of those allowed in 403.07.

440.02 Materials. Furnish materials conforming to:

Asphalt binder .................................. 702.01 Aggregates (base courses) ................ 703.04 Aggregates (intermediate and surface courses) ................................... 703.01 and 703.05 Mineral filler ................................... 703.07 If 100 percent of coarse aggregate in an asphalt mix design is steel slag ( 703.01.E), the Contractor may include steel slag as a maximum of up to 50 percent of fine aggregate. If a steel slag source causes bulking (expansion resulting in flushing or material loss) in asphalt concrete courses, OMM will place limits on the amount of steel slag allowed in a mix design. Bulking may be shown through testing, such as ASTM D4792, or through field failure such as, but not limited to, flushing on newer pavement or apparent over-asphalting in production. The Department may require the steel slag processor at any time to perform additional testing to verify steel slag properties. Pot ential mix problems due to poor control of steel slag aggregate include bulking, poor gradation and specific gravity control resulting in highly variable void properties, excess soft pieces resulting in pock marks, flushing, etc.

440.03 JMF Submittal. Submit no more than two JMFs for each asphalt concrete pay item per

project. Additional submittals are at the discretion of OMM. Develop a JMF to comply with the mix design criteria and submit it to OMM on approved forms and in AWP at least four weeks prior to the start of production for preliminary approval. OMM may require additional time prior to preliminary approval to perform tests on lab or plant produced mixtures to ensure adequate mix performance. OMM will notify the Contractor if additional time for testing is required. Based on the results of this testing, OMM may require the Contractor to design a new JMF. Identify the PG Binder supplier, as well as the polymer type if applicable, on the JMF submittal. A change in polymer asphalt binder or polymer source will require a redesign. Provide on one page neatly summarized, dated test results for the requirements of Table 702.01-1. Ensure data is no more than two months old. If SBR polymer is added at the asphalt concrete mixing plant, provide in the JMF data from the SBR polymer supplier for total solids (percent) and ash (percent) according to the 702.14. As well, provide the target amount of SBR polymer greater than or equal to 3.5 percent to achieve the properties specified. Include a letter of certification from the polymer supplier verifying percent butadiene in the SBS or SBR polymer. Report in the J MF submittal results of temperature -viscosity testing for mixing and compaction temperatures. For polymer asphalt binders, supplier recommended temperatures may be used in lieu of the temperature -viscosity results, but the temperature -viscosity results must still be reported. For Superpave mixes, include the standard Department cover and summary page, all printouts from the gyratory compactor (all gyratory points not necessary), and analysis covering the required mix properties in the JMF submittal. Ensure the JMF submittal includes the percentages of RAP, RAS, virgin aggregates, and virgin asphalt binder required for the mix item. Report all RAP and RAS test results, including binder blend analysis, in the JMF submittal. Identify the RAP in the JMF s ubmittal as to project origin and mix type(s). Identify the approved manufactured shingle waste manufacturer source or the approved tear - off RAS processor in the JMF submittal. Baghouse fines from the mix plant and mineral filler may be used in the JMF, however, limit the combination of both to 2.0 percent by weight of total aggregate. Use the lowest fine aggregate Gsb listed in the JMF submittal for the baghouse fines. Use the mineral filler Gsb on the aggregate annual gravity list and if not on the list, then have the mineral filler tested by an AASHTO accredited lab. Provide the required certification forms in the JMF submittal documenting that the RAS meets AASHTO M350 and that RAS from roofing tear -offs conforms to the EPA’s NESHAP, 40 CFR 61 Subpart M, and other applicable agency requirements for asbestos. Note on the JMF submittal RAP page whether Method 1 or Method RAP processing is used. For surface course JMF submittals having polymer asphalt binder and RAP, including 424 mixes, do not submit any blends having 1 through 9 percent RAP. Include RAS in a JMF submittal according to the Standard RAP/RAS Limits Table 440.05-1 or Extended RAP/RAS Limits Table 440.05-2 unless specified differently in the applicable mix specification. Include any required antistrip additive in the mix design but perform the volumetric design without the antistrip additive. Submit the following to OMM with the proposed JMF:

440.04 Composition. Perform the mix design and supply all required data in a manner taught in

Level 2 Asphalt Technician School, Level 3 Asphalt Mix Design School and in the most recent Asphalt Institute Manual Series No. 2 (MS-2). OMM may visit the Level 3 mix design lab for review. Provide a mix design with at least four asphalt binder content points but no more than five, including a minimum of two points above and two points below the JMF asphalt binder content. Design using HMA temperatures and do not use WMA additives during design. Use a two hour cure for volumetric mix samples and ensure the cure temperature and specimen compaction temperature are the same. Select the JMF asphalt binder content using the design air voids of the mix type and ensure the JMF meets the other requirements of the specified mix. Determine air voids from specimens prepared and tested according to Supplement 1036. Unless otherwise directed, submit an uncompacted sample for MSG representing the JMF meeting the minimum sample size in Supplement 1036 and three Marshall or two gyratory compacted specimens at design air voids. Submit additional samples as requested by OMM. Do not apply the gradation requirements of 703.05 for fine aggregate. Use the effective asphalt binder content when calculating the F/A ratio. Calculate the effective asphalt binder content according to the Department’s Asphalt Level 2 procedures. The value (calculated to the nearest percentage point) of the Fifty to Thirty (F -T) value, is the percent of total aggregate retained between the No. 50 (300 m) and No. 30 (600 m) sieves, minus the percent of total aggregate retained between the No. 30 (600 m) and No. 16 (1.18 mm) sieves. The Contractor may use the Marshall flow test in Superpave design as an indicator of potential for excess tenderness.

440.05 Reclaimed Asphalt Concrete Pavement and Reclaimed Asphalt Shingles . Provide

reclaimed asphalt concrete pavement (RAP) and reclaimed asphalt shingles (RAS) according to the following requirements when choosing to use one or both in a mix. Failure to follow these requirements will result in a rejection of the Contractor QCP (403.03); restriction of the use of any RAP, RAS, or both at the facility; a change to Restricted Acceptance at the facility; or any combination thereof. Provide RAP obtained from verifiable Department or Ohio Turnpike Commission projects and RAS obtained from un-used manufactured shingle waste or used roofing tear-off shingles as listed in Tables

440.05 1 and 440.05-2 and as follows. If the RAP is not from the above sources or the source is

unknown, process and blend the RAP into a single uniform stockpile, test according to Level 3 Asphalt Mix Design requirements and obtain OMM approval for use. Obtain written approval from OMM for use of unusually large, old RAP stockpiles of unknown content, age, or both. Include approved methods in the QCP for ongoing processing and testing of these piles. Ensure no foreign or deleterious material is present in RAP. Use approved RAS suppliers meeting the requirements of Supplement 1116. Ensure that the percentages of RAP and RAS fall within the specified limits of the required mix item. Determine the final RAP gradation and asphalt binder content on a minimum of four separate stockpile (or roadway for concurrent grinding) samples. A RAP pile will be considered established if all samples agree within a range of 0.4 percent for asphalt binder content and 5 percent passing the No. 4 (4.75 mm) sieve. If fractionated RAP is used, use a suitable sieve for determining gradation uniformity. Give each RAP stockpile a unique identification according to 402.04.D. Determine RAP binder content from a centrifuge extraction test. Do not use reflux extraction or oven burnoff. Do not add RAP or other materials to established RAP piles. Once an established RAP pile is added to or used up, the RAP pile is no longer established and all JMF’s associated with the pile are no longer approved. Notify OMM of JMF’s impacted and JMF approval will be withdrawn . Use no more than 3.0 percent RAS by dry weight of mix. For design assume 10.0 percent available RAS binder. Determine gradation and specific gravity according to AASHTO PP 78 -17 (2021), Section 5 or subsequent AASHTO applicable standard. If the uniform stockpile will be processed into the asphalt plant using plant cold feed in line processing determine the processed RAP properties for use in the mix design. Record in the JMF submittal both the uniform stockpile and in line processed RAP properties. Submit a new JMF for each existing mix type on the project (or each milling pass of two types) desired for use as concurrent project RAP.

440.05 2 Method 2. Use PG 64 -28 virgin binder in all 442 intermediate courses regardless of the

percentage of RAP used. If greater than 25 percent RAP is used in a JMF submittal use PG 58 -28 or PG 64-28 virgin binder. If 26-30 percent RAP is used in the JMF submittal, the Contractor may submit a 10,000-gram RAP sample along with a blend chart using the PG grading system, according to the Department’s Level 3 Mix Design procedures and MS -2 Section 11.4.2, to determine the grade of virgin asphalt binder to use. When using both 15 percent or greater RAP and 3 percent RAS in in the JMF submittal for intermediate and base courses, use PG 58-28 or PG 64-28. ODOT may request RAP samples, RAS samples, binder properties, or any combination at any time. When using RAS, blend the mixture meeting the proposed mix design proportions, extract and recover, and PG grade according to the Department’s Level 3 Mix Design procedures and MS -2 Section 11.4.2. If the combined binder exceeds the proposed PG grade at the high or low temperature, redesign or do not use RAS

440.05 1 unless specified differently in the applicable mix specification.

TABLE 440.05-1 METHOD 1 – STANDARD RAP/RAS LIMITS Asphalt Mix Application Percent RAP by Dry Weight of Mix, Max.[1] RAS Usage [2] Total Virgin Asphalt Binder Content, Min. Comments 442 Polymer Surface Course 10%[3] None 5.2 Polymerized binder is virgin. (For non-polymer virgin binder allow 20% max RAP) 424 Fine Graded Polymer 10% [3][4] None [5] 441 Surface Course 20% None 5.0 Polymer or non-polymer virgin. 441, 442 Intermediate Course 35% Manufacturing waste and tear- offs 3.0 Any mix type used as an intermediate course. 301 Base Course 50% Manufacturing waste and tear- offs 2.7 OMM will establish the asphalt binder content. 302 Base Course 40% (30%) Manufacturing waste and tear- offs 2.0 OMM may limit RAP to 30 percent, eliminate RAS, or both if poor production mixing or coating is evident.[6] [1] When using RAP and RAS in combination, use no more than 25 percent RAP. [2] No more than 3.0 percent RAS by dry weight of mix. [3] Use zero or 10 percent. Do not submit blends with 1 to 9 percent RAP. [4] Type B mixes only. Do not use RAP in Type A mixes. [5] The requirements of 424 apply. [6] OMM will adjust the virgin binder content if the lower limits apply.

440.06 Antistrip Additive. Use liquid antistrip (LAS) additives meeting the requirements of

440.06 A, or hydrated lime meeting the requirements of 440.06.B. LAS or hydrated lime is required

to be used for all mixes if the proposed JMF contains any gravel coarse aggregate, contains more than 25 percent natural sand, or contains more than 20 percent RAP containing gravel coarse aggregate. Conduct the tests listed in Table 440.06-1 for all 442 mixes and all mixes requiring LAS or hydrated lime. The minimum TSR result is 0.80. TABLE 440.06-1 ANTISTRIP TESTS Test Description Specification Moisture damage potential test Supplement 1051 Washed gradation AASHTO T 11 as modified by Supplement 1004 Adherent fines test for each component Supplement 1118 For 442 mixes, add, if not already required, or increase LAS or add hydrated lime, if the results of the moisture damage potential test show the TSR of the asphalt concrete mix to be less than 0.80. Increase LAS for all other mixes if the results of the mo isture damage potential test show the TSR of the asphalt concrete mix to be less than 0.80.

440.07 Tonnage Conversion. If an OMM established mix design conversion factor from the

approved JMF is not available, OMM will use the factors in Table 440.07-1. TABLE 440.07-1 CONVERSION FACTORS Aggregate lb/yd³ (kg/m³) Gravel and stone 4000 (2370) Slag less than 90 lb/yd³ (less than 1450 kg/m³) [1] 3600 (2135) Slag 90 to 100 lb/yd³ (1450 to 1600 kg/m³) [1] 4000 (2370) Slag more than 100 lb/yd³ (more than 1600 kg/m³) [1] 4300 (2550) [1] Based on average dry rodded weight at the Laboratory.