- 823 - SECTION 1028 -- SUPERPA VE ASPHALTIC CONCRETE
1028.01 Description
1.a. Superpave Asphaltic Concrete is a Contractor-designed mix.
b.The Contractor shall be r equired to define properties using a gyratory compactor that has met the Superpave evaluation test procedures, during mix design and production.
2.Job Mix Formula
a.Before production of asphaltic concrete, the Contractor shall submit, in writing, a tentative Job Mix Formula (JMF) on the NDOT Mix Design Submittal Form for verifica tion and approval to the Department.
b.The JMF shall be determined from a mix design for each mixture. A volumetric mixture design in accordance with AASHTO R 35 as modified within this Specification wi ll be required. The mixture shall be prepared using the following:
1.Mixture Conditioning of Hot Mix Asphalt (HMA), AASHTO R 30. The mixture for the Superpave specimens and maximum specific gravity mixture shall be ag ed for 2 (two) hours at compaction temperature.
2.Method for Preparing and Determining the Density of Hot Mix Asphalt Specimens by Means of the SHRP Gyratory Compactor, AASHTO T 312.
c.The JMF shall identify: (1) The virgin mineral aggregates and pit locations (2) RAP and source locations
3.Hydrated lime or Warm Mix Additive
4.Mineral filler (5) The percent passing value for each specified sieve for the individual and blended materials
d.(1) The Contractor shall submit the following, at a minimum, for basic mix verification: 1 (one) uncoated, proportioned 22 lb. (10,000 gram) sample of the blended mineral aggregates for consensus properties and specific gravity testing, for all mix types except SPS.
2.The Contractor has the option of submitting the following for a more detailed mix design verification; 2 (two) proportioned 22 lb. (10,000 gram) samples of the blend ed mineral aggregates (which are precoated with hydrated lime, if lim e is used) and two one-quart (liter) samples of the proposed PG Binder to be used in the mixture to the Department Materials and Research C entral Laboratory at least 15 NDOT working days before production of asphaltic concrete.
3.Submitted with these samples shall be a copy of the Contractor’s results for all Superpave mix design tests.
4.Mix design shall include at a minimum: (i) The bulk specific gravity (Gsb), which shall be 2.585, for data purposes and as information only, for all mixes.
1028.01 Superpave Asphaltic Concrete
- 824 - (ii) The target binder content. The binder content will be determined by ignition oven results. A corre ction factor of 0.3% will be added to the ignition oven results for mixes containing hydrated lime, and an adjustment factor of 0.1% will be added to the ignition oven results for mixes containing WMA. (iii) The supplier and grade of PG Binder. (iv) The maximum specific gravity of the combined mixture (Rice).
v.The bulk specific gravity (Gmb) and air voids at N initial (Nini), N design (Ndes) and N maximum (Nmax) of the gyratory compacted specimens. (vi) Voids in the Mineral Aggregate (VMA) and Voids Filled with Asphalt (VFA) at Ndes. (vii) Fine Aggregate Angularity (FAA) and specific gravity, Coarse Aggregate Angularity (CAA). (viii) Location description and/or legal descriptions and producers of materials used in the mix. (ix) Dust to Binder Ratio (x) JMF compaction temperatures from NDOT Gyratory Temperature Table (See Table 1028.11). (xi) The hydrated lime content. 3. Quality Control Program: a. The Contractor shall establis h, provide, and maintain an NDOT approved Quality Control (QC) Program. The QC Program shall detail the methods and procedures that will be taken to assure that all materials and completed construction conforms to all contract requirements. The QC program shall be updated and submitted annually for review and approval. A copy of the QC Program shall be kept on file in the QC lab trailer.
b.Although guidelines are established and certain minimum requirements are specified herein and elsewhere in the contract, the Contractor shall assume full responsibi lity for placing a pavement that meets the contract specific ation requirements.
c.The Contractor shall not begin any construction of asphalt pavements or production of material s without an approved QC Program and approved JMF
4.Contractor’s Lab Equipment: a. The Contractor shall cali brate and correlate the testing equipment according to the procedures described for the individual tests and conduct tests in conformance with spec ified testing procedures as outlined during the annual laboratory approval provided by NDOT Materials and Research Division.
5.QC Testing Plan:
a.The testing plan shall provid e that the samples be collected in accordance with the Department st atistically based procedure of random sampling. Superpave Asphaltic Concrete 1028.02 - 825 - b. The Contractor may add any tests necessary to adequately control production.
c.All QC test results shall be reported on the latest version of the Department’s provided Superpave software by the Contractor with a copy provided to the Engineer within 1 (one)week after the tests are complete. Daily review by the Engineer shall be allowed. At the completion of the asphalt production, the Contractor sh all submit to the Department a final copy of the Superpave test results on electronic recording media (CD, email, flash drive, etc.).
d.Procedures shall be defined to perform corrective action when any mix properties are out of spec ification when plant and production problems occur, when laydown problems occur such as, but not limited to: rutting, segregation, surface voids, teari ng, contamination, irregular surfaces, surface irregularities.
1028.02 Material Characteristics
1.The type of PG Binder will be sh own in the contract, except for the following:
a.SLX mixes shall be 58V-34 with 0.7% of an approved WMA additive.
b.SRM mixes shall be 58H-34 with 0.9% of an approved WMA additive.
2.Recycled Asphalt Pavement: a. The Contractor may submit to the State a proposal to supplement the virgin aggregates of the asphaltic concrete mix with a Contractor’s specified per centage of RAP. The Contractor is responsible for investigating and maintaining the qua lity and verifying the quantity of the RAP material. The RAP must be pre-processed by fractionating, screening, and or crushing prior to use to a size such that the combined hot mix meets the required gradation. The mat shall not exhibit any visual defects or cold spots from RAP conglomeration.
b.In recycled asphaltic concrete mixtures, the allowable percent of RAP will be as shown in Table 1028.01. Table 1028.01 Asphaltic Concrete Type Percent, RAP Minimum Maximum SPS 0 65 SPR 0 55 SPH 0 35 SLX 20 35 SRM 35 65
3.Aggregates:
a.Aggregates for use in super pave asphaltic concrete shall be tested on an individual basis.
1028.02 Superpave Asphaltic Concrete
- 826 - b. With the exception of Asphaltic Concrete Type SPS the blended mineral aggregate shall no t contain more than 80% limestone on the final surface lift of asphaltic concrete.
c.Asphaltic Concrete Type SLX shall contain a minimum of 20% Crushed Rock Chips (with a minimum of 45% retained on the #4 sieve and a maximum of 5% passing the #200 sieve).
d.Asphaltic Concrete Type SRM shall contain a minimum of 10% Crushed Rock (with a maximum of 20% passing the #4 sieve).
e.Asphaltic Concrete Type SPR, SLX, and SRM may contain a total maximum of 10% of the virgin mate rial that is composed of natural, uncrushed aggregate by manmade methods commonly known as but not limited to: 47B gravel, 2A gravel, gravel surfacing, sluice sand, blow sand, waste sand, fill sand, road gravel, roof ing gravel, hot mix sand or gravel, coarse sand, fine sand, plaster sand, masonry sand, pit run sand or gravel. For clarification on any proposed grav el, contact the Department Flexible Pavements Engineer.
f.Chat or coal sand will not be allowed in any mix.
g.Crushed rock material for use in asphaltic concrete, 1/4 inch (6.35 mm) and smaller, screenings and manufactured sand shall have a Sodium Sulfate loss of not more than 12% by mass at the end of 5 (five) cycles. Sampling size and frequency shall adhere to the current Department Materials Sampling Guide.
h.Quartzite and granite sha ll conform to the requirements of Subsection 1033.02, Paragraph 4, a. (8 ). Sampling size and frequency shall adhere to the current Department Materials Sampling Guide.
i.Crushed rock (Limestone) and Dolomite shall conform to the requirements of Paragraph 4.a. (4), (5) and (6). of Subsection 1033.02 of the Standard Specifications, Sampling size and frequency shall adhere to the current Department Materials Sampling Guide.
j.Soundness tests shall not be required for fine sand.
k.Once the satisfac tory quality of aggregates from a source has been established, sufficient additional soundness tests will be performed to insure the continued satisfactory quality of the material, as determined by the Department’s Materials Sampling Guide.
l.Aggregate consensus prop erties may be performed on material prior to the application of hydrated lime.
m.The coarse aggregate angul arity value of the blended aggregate material shall meet or exceed the minimum values for the appropriate asphaltic concrete type as shown in Table 1028.02. Superpave Asphaltic Concrete 1028.02 - 827 - Table 1028.02 Coarse Aggregate Angularity (ASTM D 5821) Asphaltic Concrete Type CAA (minimum) SPS -- SPR 83 SPH 95/90* SLX -- SRM 65 * Denotes two faced crushed requirements
n.The fine aggregate angulari ty value of the blended aggregate material shall meet or exceed the minimum values for the appropriate asphaltic concrete type as shown in Table 1028.03.
o.The specific gravity for calc ulation of the Fine Aggregate Angularity (FAA) shall be determined on a washed combined aggregate sample of the material passing the No. 8 (2.36 mm) sieve and retained on the No. 100 (150 µm) sieve. The Cont ractor will determine the specific gravity to be used in the calculation of FAA mixture design value(s) and, if verified by the Department Aggregate Laboratory, this same value can be used throughout production. The verification value determined by the Department Aggregate Lab oratory will be on a combined aggregate sample supplied by the Contractor that is repr esentative of the material proposed or being used during production. The specific gravity to be used throughout production to calculate FAA values will be the Contractor’s verified value or the Department determined value (whenever verification is not made) and will be noted on the Mix Design. C hanges in aggregate percentages during production may require determination of a revised specific gravity for FAA. Table 1028.03 Fine Aggregate Angularity (AASHTO T304 Method A) Asphaltic Concrete Type FAA (minimum) SPS -- SPR 43.0 SPH 45.0 SLX 43.0 SRM 42.0
p.Dust to binder ratio is the ra tio of the percentage by weight of aggregate finer than the No. 200 (75 µm) sieve to the asphalt content expressed as a percent by weight of to tal mix. The dust to binder ratio shall be within 0.70 and 1.70 for all mixes except SRM. SRM dust to binder ratio shall be within 0.70 and 1.90.
1028.02 Superpave Asphaltic Concrete
- 828 - q. The blended aggregate s hall conform to the gradation requirements specified in the following Tables. Table 1028.04 Gradation Control Points for SPH 0.5 Inch 0.5 Inch Control Points (Percent passing) English Sieve (Metric) Minimum Maximum 1 inch (25 mm) 100.0 3/4 inch (19 mm) 100.0 100.0 1/2 inch (12.5 mm) 90.0 100.0 3/8 inch (9.5 mm) 90.0 No. 8 (2.36 mm) 28.0 58.0 No. 16 (1.18 mm) No. 30 (600 m) No. 50 (300 m) No. 200 (75 m) 2.0 10.0 Table 1028.05 Gradation Control Points for Type SRM (Percent passing) (Metric) Minimum Maximum 3/4 inch (19 mm) 92.0 98.0 3/8 inch (9.5 mm) 80.0 92.0 No. 8 (2.36 mm) 42.0 60.0 No. 50 (300 µm) 10.0 22.0 *No. 200 (75 µm) 4.0 12.0 Table 1028.06 Gradation Control Points for SLX SLX Control Points (Percent passing) English Sieve (Metric) Minimum Maximum 3/4 inch (19 mm) 100.0 100.0 1/2 inch (12.5 mm) 98.0 100.0 3/8 inch (9.5 mm) 93.0 100.0 No. 4 (4.75 mm) 70.0 87.0 No. 8 (2.36 mm) 45.0 65.0 No. 16 (1.18 mm) 25.0 41.0 No. 30 (600 m) 15.0 31.0 No. 50 (300 m) 10.0 21.0 No. 200 (75 m) 4.0 10.0 Superpave Asphaltic Concrete 1028.02 - 829 - Table 1028.07 Gradation Control Points for SPR SPR Control Points (Percent passing) English Sieve (Metric) Minimum Maximum 3/4 inch (19 mm) 98.0 100.0 1/2 inch (12.5 mm) 3/8 inch (9.5 mm) 81.0 89.0 No. 4 (4.75 mm) No. 8 (2.36 mm) 46.0 56.0 No. 16 (1.18 mm) No. 30 (600 m) No. 50 (300 m) 12.0 21.0 No. 200 (75 m) 4.0 9.0 Table 1028.08 Gradation Control Points for SPR (Fine) SPR (Fine) Control Points (Percent passing) English Sieve (Metric) Minimum Maximum 3/4 inch (19 mm) 1/2 inch (12.5 mm) 3/8 inch (9.5 mm) 81.0 96.0 No. 4 (4.75 mm) No. 8 (2.36 mm) 46.0 56.0 No. 16 (1.18 mm) No. 30 (600 m) No. 50 (300 m) 12.0 21.0 No. 200 (75 m) 4.0 9.0 Table 1028.09 Gradation Control Points for Type SPS Control Points (Percent passing) English Sieve (Metric) Minimum Maximum 1 inch (25 mm) 100.0 ¾ inch (19 mm) 94.0 100.0 ½ inch (12.5 mm) 81.0 100.0 No. 4 (4.75 mm) 70.0 90.0 No. 8 (2.36 mm) 42.0 70.0 No. 16 (1.18 mm) 29.0 43.0 No. 30 (600 m) 19.0 34.0 No. 50 (300 m) 11.0 20.0 No. 200 (75 m) 2.0 10.0
1028.03 Superpave Asphaltic Concrete
- 830 - 1028.03 -- Acceptance Requirements
1.Mix Criteria:
a.The target value for the air voids of the SPH Asphaltic Concrete shall be 4% (±1%) at the Ndes number of gyrations. For Type SPS Asphaltic Concrete the air voids at Ndes shall be a minimum of 1.5% with a maximum of 5.0%. For Type SPR Asphaltic Concrete the air voids shall be 3% (±1%) at the Ndes number of gyrations.
b.The design criteria for each mixture shall be determined from Tables 1028.10, 1028.11, and 1028.12. Table 1028.10 Gyratory Compaction Effort (Average Design High Air Temperature <39 degrees C) Asphaltic Concrete Type Nini Ndes Nmax SPS 6 40 62 SPR 7 65 100 SPH 8 95 150 SLX 50 SRM 65 Table 1028.11 Gyratory Compaction Temperatures Mix Type Percent RAP Compaction Temp °F SPS 0-25 270 ± 5 26-65 280 ± 5 SPR 0-35 280 ± 5 36-55 290 ± 5 SPH 0-35 300 ± 5 SLX 20-35 280 ± 5 SRM 35-65 290 ± 5 Table 1028.12 Minimum Binder Content Mix Type (Metric) Minimum Binder Content, Percent SPS 4.8 SPR 5.0 SPH 5.1 SLX 5.3 SRM 4.5
c.During production of Lot #1 and randomly selected lots thereafter, the Contractor shall provi de to the Department 6 (six) properly prepared gyratory samples for AASHTO T 283 testing for all mixtures except Superpave Asphaltic Concrete 1028.03 - 831 - Asphaltic Concrete Type SPS. Super pave mixtures shall contain 1.25% hydrated lime as specified in the Sp ecial Provision “Hydrated Lime for Asphaltic Mixtures”. Each Superpave mixture shall be tested for moisture sensitivity in accordance with AASHTO T 283. The 6 inch (150 mm) specimens shall be compacted in accordance with AASHTO T 312 to 7% (± 0.5%) air voids at 95 mm in height an d evaluated to determine the Tensile Strength Ratio (TSR).
2.The Contractor shall make Mix adjustments when: a. The mix does not meet the current approved JMF or any other mix properties or requir ements of the contract.
b.Surface voids create a surfac e or texture that does not meet the criteria of Sections 502 and 503 in these Standard Specifications.
c.Rutting occurs.
3.The Contractor shall inform th e Engineer when changes in mixture properties or materials used occur for any reason. Changes such as, but not limited to, types or sources of aggregat es or changes in grades, sources, properties or modification procedur es (if modified) of PG Binders. The Department may require a new job mix formula, mix design and moisture sensitivity test. The new proposed job mix formula shall be in accordance with the requirements as stated above.
4.Mix adjustments at the plant are authorized within the limits shown in Table 1028.13 as follows:
a.The adjustment must produce a mix with the percent air voids and all other properties as stat ed in these Specifications.
b.All adjustments must be reported to the Engineer.
c.The adjustment values in Table 1028.13 will be the tolerances allowed for adjustments from the Department verified mix design “Combined Gradation” target values which result ed from production or mix design adjustments, but cannot deviate from Superpave gradation criteria. Mix adjustments for individual aggregates, including RAP, greater than 25% of the original verified mix design proportion or greater than 5% change in the original verified mix design percentag e, whichever is greater, may require the Contractor to submit a new mix design, as determined by the Engineer. The Contractor is responsible for requ esting new mix design targets as they approach these tolerances, failure to do so may result in a suspension of operations until a new mix design is approved. Table 1028.13 Aggregate Adjustments Sieve Size Adjustments 1 inch (25 mm), 3/4 inch (19 mm), 1/2 inch (12.5 mm), 3/8 inch (9.5 mm), No. 4 (4.75 mm) ± 6% No. 8 (2.36 mm), No. 16 (1.18 mm), No. 30 (600 µm), No. 50 (300 µm) ± 5% No. 200 (75 µm) ± 2%
5.Sampling and Testing:
a.The Contractor shall take sa mples at frequencies identified by the Engineer, according to the Departm ent statistically based procedure.
1028.03 Superpave Asphaltic Concrete
- 832 - The samples shall be approximately 75 lbs (34 kg) and split according to AASHTO T 248 to create a companion sample. This sample splitting can be either at: 1) the sampling location, with the Department taking custody of their sample at that time or 2) after being transported to the test facility in an insulated container, with the Department taking custody of their sample at that time as determined by the Engineer. The details of sampling, location, splitting etc. shall be determined at the pre-construction conference.
b.All samples transported to the test facility and companion samples within the Lot shall be identified by attaching or faxing the lab calculation sheet from the latest vers ion of the superpave software, stored, and retained by the Contractor until the Department has completed the verification testing process. Transporting of all samples will be under the observation of Department.
c.(1) The sample shall be taken from the roadway, behind the paver before compaction or from the windrow. For SPS mixes, the Contractor has the option to obtain the samples directly at the plant.
2.At least one QC sample shall be tested for every 1,000 tons of plant produced mix.
i.If, at the completion of the project, the final lot consists of less than 5,000 tons of asphaltic concrete, 1 (one) sample for each 1,000 tons or fraction ther eof, shall be taken and tested.
3.Additional sampling and testing for the Contractor's information and quality control may be performed at the Contractor's discretion. Any additional testing will not be used in pay factor determination.
4.(i) When cold feed samples are being taken, the acquisition shall be timed su ch that the material in the sample represents, as close as possible, the same material in the sample taken behind the paver. If cold feeds are sampled and tested by Cont ractor, a split of that sample must be submitted with the hot mix sublot sample. The Contractor will be notified what sublot (a minimum of 1 (one) subl ot per lot) sample must be tested for FAA and CAA from the blended cold feed material according to the Department random sampling schedul e. All other FAA and CAA sublot samples may be taken from the randomly selected portion of the blended cold feed material or obtained from the random samples taken behind the paver. Samples shall be taken under the observation of Department and split according to AASHTO T 248, with the Department taking custody of their sample at that time. (ii) For projects using RAP material the FAA shall be established as follows: a RAP sample will be processed through an ignition oven and then combined with the prop ortioned amount of virgin aggregate defined by the mix design and then proceeding with FAA and CAA testing.
d.The sample shall be compacted immediately while still hot (additional heating may be required to rais e the temperature of the sample to compaction temperature).
e.Each production sample shall be tested as follows: (1) Bulk Specific Gravity (Gmb) shall be determined for each specimen in accordance with AASHTO T 166 Bulk Specific Gravity of Superpave Asphaltic Concrete 1028.03 - 833 - Compacted Bituminous Mixtures Usi ng Saturated Surface Dry Specimens. One specimen shall be compacted for each production sample.
2.One Theoretical Maximum Specific Gravity (Gmm) test for each production sample of uncompac ted mixture shall be determined in accordance with AASHTO T 209 procedure 13.1. Weight in water - Maximum Specific Gravity of Bituminous Paving Mixtures.
3.(i) The Blended Aggregate Bulk Specific Gravity (Gsb) shall be 2.585 for information only for all mixes. (ii) FAA - AASHTO T 304 Method A. The pour time of the test sample into the funnel shall be completed in 5±1 seconds. (iii) CAA - ASTM 5821. For SPR mixes, CAA testing and results are only required on the cold feed verification test for the lot.
4.The laboratory air voids shall be determined in accordance with AASHTO T312 and T269.
5.(i) The percent of PG Binder shall be determined for each QC test. The percent of PG Binder will be computed by ignition oven results. A correction factor of 0.3% wi ll be added to the ignition oven results for mixes containing hydrated lime. (ii) The gradations shall be determined for each QC test using AASHTO T 30.
6.Except as noted in this Subsection, all sampling and testing shall be done as described in the Department Materials Sampling Guide and Standard Method of Tests.
f.Testing Documentation: (1) All test results and calculations shall be recorded and documented on data sheets using the la test version of Department provided “Superpave” software. A copy containing complete project documentation will be provided to the Department at the completion of asphalt production.
g.Superpave Software: (1) QC charts from the software shall be made available for review by the Engineer at any time.
2.As a minimum, the following values shall be reported on Department provided software:
i.Laboratory Gyratory density. (ii) Ignition oven or co ld feed aggregate gradations for all Superpave sieves will be reported. (iii) PG Binder content shall be plotted to the nearest 0.01% by ignition oven results in accordance with AASHTO T 308. (iv) The theoretical maximu m specific gravity (Rice) to the nearest 0.001% will be reported.
v.Laboratory Gyratory air voids at Ndes shall be plotted to nearest 0.1%. Laboratory Gyratory air voids, at Nini, Ndes and Nmax shall be reported to nearest 0.1%. (vi) FAA and CAA of the asphaltic concrete for both cold feed and ignition oven samples will be reported to the nearest 0.1% for FAA
1028.03 Superpave Asphaltic Concrete
- 834 - and 1% for CAA. A minimum of one sublot FAA and CAA cold feed sample per lot will be tested and recorded on Department provided software. (vii) VMA content shall be plotted to nearest 0.1% and VFA shall be reported to the nearest 0.1%. (viii) Dust to Binder ratio to the nearest 0.01 will be reported.
6.Verification Sampling and Testing: a. The Department will select and test at random one of the sublot samples within a Lot for verification and report results.
b.The results of Contractor QC testing will be verified by the Department’s verification tests. Any sa mples outside of the tolerances in Table 1028.15 and 1028.16 will result in an Independent Assurance (IA) review of testing and may result in the Department test results being applied.
1.On any given Lot, if the results of Air Void verification testing and its companion QC testing are within 1.0% air voids, the Air Void verification for the entire Lot is complete and the Contractor test results will be used to determine the pay factors. If the Air Void verification test results and the companion QC test results are outside the above tolerance, the results from the verification test will be used to determine the pay factor for that sublot. Any or all of the remainin g four Department sublot samples may be tested and the Department sublot te st results may be applied to the respective sublots and the resu lting pay factors will apply.
2.On any given Lot, if the results of the FAA verification testing and its companion QC testing are within 0.7%, the FAA verification for the entire Lot is complete and the Contractor test results will be used to determine the pay factor. If the FAA verification test results and the companion QC test results are outside the above tolerance, the results from the verification test will be used to determine the pay factor for that sublot. Any or all of the remaining four Department sublot samples may be tested and the Department sublot test result s may be applied to the respective sublots and the resulting pay factors will apply.
c.When verification tests are within testing tolerance but results show a consistent pattern of deviation from the QC results, the Engineer may cease production and/or request addit ional verification testing or initiate a comprehensive IA review. Table 1028.15 Asphaltic Concrete Testing Tolerances Test Tolerance Asphalt Content by Ignition Oven 0.5% Gyratory Density 0.020 Maximum Specific Gravity 0.015 Bulk Dry Specific Gravity (Gsb) 0.020 FAA 0.7% CAA 10% Field Core Density 0.020 Air Voids 1.0% Superpave Asphaltic Concrete 1028.03 - 835 - Table 1028.16 Blended Aggregate Gradation Testing Tolerances Sieve Size Tolerance 3/4 inch (19 mm), 1/ 2 inch (12.5 mm), 3/8 inch (9.5 mm), No. 4 (12.5 mm), No. 8 (2.36 mm) 6% No. 16 (1.18 mm), No. 30 (600 µm), No. 50 (300 µm) 5% No. 200 (75 µm) 3%
d.Independent Assurance (IA) Review of Testing:
1.The Contractor shall allow the Department personnel access to their laboratory to conduct IA review of technician testing procedures and apparatus. Any deficiencies discovered in testing procedures will be reported by t he department and corrected by the Contractor.
2.During IA review, the Department personnel and the Contractor will split a sample for the purpose of IA testing. The samples selected will be tested in the Department Branch Laboratory. Any IA test results found to be outside of defined testing tolerances above will be reported. The Contractor shall verify the testing apparatus and make corrections if the apparatus is out of tolerance.
3.See Section 28 of the Department’s Materials Sample Guide for more informati on on IA testing.
e.If the project personnel a nd the Contractor cannot reach agreement on the accuracy of the test results, the Department will be asked to resolve the dispute, which will be final . It is the Contractor’s responsibility to obtain a large enough sample size for any referee testing (a total sample size of 6000 grams, to be retained by the Department after splitting, is recommended for FAA testing). All dispute resolutions will be in accordance with the Quality Assurance Program requirements in the Department’s Materials Sampling Guide.
7.Production Tolerances, A cceptance, and Pay Factors
1028.03 Superpave Asphaltic Concrete
- 836 - Table 1028.17 Production Tolerances* Test Allowable Deviation from Specification Dust to Asphalt Ratio None Coarse Aggregate Angularity - 5% below Min. Fine Aggregate Angularity for SPR, SLX, and SRM - 0.2% below Min. for cold feed or - 0.5% below Min. for ignition oven Fine Aggregate Angularity for all other mixes - 0.5% below Min. for cold feed or - 1.0% below Min. for ignition oven Minimum Binder Content None * These tolerances are applied to the mix design specification values, not the submitted mix design targets.
a.The Contractor shall notify th e Engineer whenever a test result approaches the Specification limits.
b.When any single test result for FAA testing falls outside the allowable production tolerances in T able 1028.17, the material represented by this test will be accepted with a 20% penalty or rejected, as determined by the Engineer. For all other tests, when any single test result, on the same mix property, from two consecutive QC samples fall outside the allowable production tolerances in Table 1028.17, the material represented by these tests will be accepted with a 20% penalty or rejected, as determined by the Engineer.
c.The Contractor has the responsibility to cease operations when specifications are not being met.
d.Acceptance and pay factors for Asphaltic Concrete Type SPS will be based on compacted in place average density and joint density.
e.When a control strip is not c onstructed, the pay factor for the running average of four air voids shal l be fixed at 1.0 for the first three asphaltic concrete sublots.
1.When there is a production tolerance pay factor penalty as stated in Paragraph 7.b. subsection 1028. 03 this penalty percentage will be entered in the Superpave Asphalt Pa y Factor Summary under production specifications for each sublot affected.
f.The pay factors for the single test air voids and moving average of four air voids pay factors will be determined in accordance with Table 1028.18. Superpave Asphaltic Concrete 1028.03 - 837 - Table 1028.18 (SPR) Acceptance Schedule Air Voids - N des Air voids test results for Asphaltic Concrete Type SPR Pay Factor Moving average of four Single test Less than 0.5% 50% or Reject 50% or Reject 0.5% to 0.9% 50% or Reject 50% 1.0% to 1.4% 50% or Reject 95% 1.5% to 1.9% 90% 95% 2.0% to 2.4% 100% 100% 2.5% to 3.5% 102% 104% 3.6% to 4.0% 100% 100% 4.1% to 4.5% 95% 95% 4.6% to 5.0% 90% 95% 5.1% to 5.5% 50% or Reject 90% 5.6% to 6.0% 50% or Reject 50% 6.1% and over 50% or Reject 50% or Reject Table 1028.18 (SPH) Acceptance Schedule Air Voids - N des Air voids test results for SPH Asphaltic Concrete Pay Factor Moving average of four Single test Less than 1.5% 50% or Reject 50% or Reject 1.5% to 1.9% 50% or Reject 50% 2.0% to 2.4% 50% or Reject 95% 2.5% to 2.9% 90% 95% 3.0% to 3.4% 100% 100% 3.5% to 4.5% 102% 104% 4.6% to 5.0% 100% 100% 5.1% to 5.5% 95% 95% 5.6% to 6.0% 90% 95% 6.1% to 6.5% 50% or Reject 90% 6.6% to 7.0% 50% or Reject 50% 7.1% and over 50% or Reject 50% or Reject
1028.03 Superpave Asphaltic Concrete
- 838 - Table 1028.18 (SLX) Acceptance Schedule Air Voids - N des Air voids test results for Asphaltic Concrete Type SLX Pay Factor Moving average of four Single test Less than 0.5% 50% or Reject 50% or Reject 0.5% to 0.9% 50% or Reject 50% 1.0% to 1.4% 50% or Reject 95% 1.5% to 1.9% 90% 95% 2.0% to 2.4% 100% 100% 2.5% to 3.5% 102% 104% 3.6% to 4.0% 100% 100% 4.1% to 4.5% 95% 95% 54.6% to 5.0% 90% 95% 5.1% to 5.5% 50% or Reject 90% 5.6% to 6.0% 50% or Reject 50% 6.1% and over 50% or Reject 50% or Reject Table 1028.18 (SRM) Acceptance Schedule Air Voids - N des Air voids test results for Asphaltic Concrete Type SRM Pay Factor Moving average of four Single test Less than 0.4% 50% or Reject 50% or Reject 0.5% to 0.9% 50% or Reject 95% 1.0% to 1.4% 90% 95% 1.5% to 1.9% 100% 100% 2.0% to 3.0% 102% 104% 3.1% to 3.5% 100% 100% 3.6% to 4.0% 95% 95% 4.1% to 4.5% 90% 95% 4.6% to 5.0% 90% 100% 5.1% to 5.5% 50% or Reject 90% 5.6% to 6.0% 50% or Reject 50% 6.1% and over 50% or Reject 50% or Reject
8.Asphalt Concrete Density Samples:
a.The Contractor shall perform density tests under direct observation of Department personnel. The Contractor shall establish the method of testing in the preconstru ction conference and shall test in accordance with the AASHTO T 166, NDOT T 587, or as otherwise described in these Special Provisions. T he Contractor shall insure that the proper adjustment bias and/or correcti on factors are used and accessible to Department personnel along with all other inputs when NDOT T 587 is Superpave Asphaltic Concrete 1028.03 - 839 - selected. All correlation factors and test results shall be generated and reported on the Department Superpave Software. When AASHTO T 166 is being used, the Department will observe the Contractor taking, transporting, and testing the cores. The Department will take immediate custody of the cores at the completion of the testing. All disputed values determined using NDOT T 587 will be resolved using AASHTO T 166.
b.The Contractor shall deter mine the density of samples by comparing the specific gravity of the core sample to the Maximum Specific Gravity (Rice). Note : The individual QC test value of the Maximum Mix Specific Gravity (Rice), determined by AASHTO T 209, will be used to calculate the density of each corresponding core.
c.The Contractor shall cut cores the first day of work following placement of the mixture. The core samples shall be a minimum of a 3 inch (75mm) diameter.
d.Normally, 1 (one) sample for determination of density will be taken from each sublot (750 tons) (680 Mg) at locations determined by the Engineer.
e.The average density of the lot shall be used to compute the pay factor for density. Exceptions to the sampling and testing of core samples for the determination of density are as follows:
1.When the nominal layer thickness is 1 inch (25 mm) or less, the sampling and testing of density for this layer will be waived. However, regardless of layer thickness, Asphaltic Concrete Type SLX will be monitored for density. For SLX, an initial rolling pattern shall be completed to determine the rolling pattern that will ta rget a minimum of 92.5% density. The Contractor shall monitor the dens ity through a combination of rolling pattern and field testing as deemed necessary by the Engineer. The Contractor will use steel wheel compactors only, rubber tire rollers will not be allowed.
2.When the average thickness of the 5 cores for a lot is 1 inch (25 mm) or less, the testing of density samples for this lot will be waived.
3.When the nominal layer thickness and the average of the original 5 (five) cores for a lot are both more than 1 inch (25 mm), but some of the cores are less than 1 inch (25 mm) thick, additional cores shall be cut at randomly selected locations to provide 5 (five) samples of more than 1 inch (25 mm) thickness for the determi nation of the pay factor for density.
f.(1) If, at the completion of t he project, the final lot consists of less than one lot of asphaltic concrete, a minimum of 3 (three) samples, or 1(one) sample for each sublot or fraction thereof, whichever is greater, shall be taken and tested for density.
2.The test results shall be averaged and the density pay factor based on the values shown in Table 1028.19.
3.Should the average of less than 5 (five) density tests indicate a pay factor less than 1.00, additional density samples to complete the set of 5 (five) shall be taken at randomly selected locations and the density pay factor based on the average of the 5 (five) tests.
1028.03 Superpave Asphaltic Concrete
- 840 - Table 1028.19 Acceptance Schedule Density of Compacted Asphaltic Concrete Average Density (5 Samples, Percent of Voidless Density) Pay Factor Greater than 92.4 1.00 Greater than 91.9 to 92.4 0.95 Greater than 91.4 to 91.9 0.90 Greater than 90.9 to 91.4 0.85 Greater than 90.4 to 90.9 0.80 Greater than 89.9 to 90.4 0.70 89.9 or Less 0.40 or Reject
g.If requested by the Contractor , check tests for all density tests in the original set, taken no later than the working day following the receipt of all test results for the lot, will be allowed in lots with a density pay factor of less than 1.00. No re-rolling will be allowed in these lots. Locations for checks tests will be provided by the Engineer from the Random Sampling Schedule. The average density obtained by the check tests shall be used to establish the density pay factor for the lot.
h.The location of density samples are identified by the Random Sampling Schedule. When the random loca tion is noted as zero or the lane width (i.e., zero or 12 ft. on a 12-foot la ne), the core shal l be cut with the outer edge of the core barrel no greater than 4 inches away (laterally) from the edge of the top of the mat for an un confined edge or from the edge of the top of the hot mat (joint) for a confined edge. If using a nuclear gauge, the 4 inches would be measured to the edge of the gauge base. The percent density value at these edge-of-lane lo cations shall be adjusted upward by 2.5%, but to a value of no greater t han 92.5%, and the resultant value used in determining the density pay factor. No initial value of 92.5% or greater shall be adjusted.
9.Basis of Payment: For each sublot of As phaltic Concrete Type SPS, SPR SPH, SLX, and SRM, the asphaltic concrete shall be paid for each ton of “Asphaltic Concrete Type ______” placed and a ccepted. The incentive/disincentive shall be calculated on a lump sum basis based on the unit price, tonnage and quality pay factors. This will be a product of all applicable pay factors, including density and smoothness. This factor will be calculated on NDOR software and will provide for a weighted pay factor for each type of Asphaltic Concrete on the project, and then summed up and paid for as a single incentive/disincentive as a lump sum. The tonnage that is applicable toward this incentive/disincentive shall only be tonnage that is paid for by ‘mainline roadway and shoulder tonnage items’ and for the full thickness and tonnage paid for and accepted. No incentive will be paid for project patching or tonnage used for maintenance patching. - 841 - SECTION 1029 -- PERFORM ANCE GRADED BINDER
1029.01 Description
1.Performance Graded (PG) binder shall conform to the requirements of AASHTO M332 Table 1. PG binder sha ll also conform to the Department PG+ specifications (Table 1029.01) wh en classified as a modified binder.
a.The test of Direct Tension, AASHTO M332 Table 1, is omitted.
b.The test of J nrdiff, AASHTO M332 Table 1, is omitted.
2.The Performance Graded Binder shall be supplied by a supplier that is certified by the Department.
a.A supplier may request certification by contacting the Nebraska Department of Transportation, Materials and Research Division, Flexible Pavement Engineer.
b.A certified supplier must furnish a quality control program to the Department Bituminous Laboratory for review and approval. The program shall follow, at a minimum, the guidelines of AASHTO R26 with references to AASHTO M320 to include AASHTO M332.
c.A certified supplier must be a participant in one or more of the following PG Binder Groups: (1) AASHTO Materials Reference Laboratory (AMRL) (2) Western Cooperative Testing Group (WCTG) (3) Combined States Binder Group (CSBG) (4) A PG Binder round robin Group approved by the Department
d.A certified supplier must maintain, meet and follow the requirements of the group or groups in which they participate, to maintain certification by the Department. In additi on, active participation is required to maintain certification by the Department. Active participation will include submitting of round robin sample results.
1.For suppliers that desire to provide product while approved PG Binder Group membership is pending, a temporary certification may be issued for a period of up to one year. Split sample testing will be required prior to receiving a temporary ce rtification. Split sample testing will be done on all grades of binder that t he supplier intends to supply during the temporary certification period. The supplier will have up to one year to become certified by participating in an d following the requirements of one or more of the approved PG Binder Groups , and to meet all other conditions for certification.
e.A certified supplier may be a sked to supply to the Department: past round robin results, laboratory inspection reports, reasons for and investigative reports on outlying resu lts, quality control testing results, technician training and/or pr oficiency testing reports.
f.A certified supplier will agree to inspection of their plant or terminal without notice anytime during pr oduction or supplying of material to the Department. The inspection may also include the supplier’s laboratory.
g.If desired, a certified supplier can voluntarily submit samples of PG binder proposed for use to the Department Materials and Research
Source: Nebraska Standard Specifications for Highway Construction, 2017 Edition. Pages 857–874 of 1,048.