610ASPHALT CONCRETE PLANT MIX PAVEMENTS

6-15 results, the Department’s quality assurance test results (including verification sample s)

and by observation of the Contractor’s total density quality control process conducted in accordance with s pecifications .

609-11 Measurement and Payment

Any mix produced that is not verified may be assessed a price reduction at the Engineer’s discretion in addition to any reduction in pay due to mix or density deficiencies. Produce and construct all asphalt mixtures and pavements in accordance with these Standard Specifications . There will be no direct payment for work covered by this Specification. Payment at the contract unit prices for the various asphalt items will be full compensation for all work covered by these specifications. If the mix or pavement repre sented by the falsified results is removed and replaced, payment will be made for the actual quantities of materials required to replace the falsified quantities, not to exceed the original amounts.

610-1 Description

Perform the work covered by this section including, but not limited to , the construction of one or more courses of asphalt mixture placed on a prepared surface in accordance with these specifications and in reasonably close conformity with the lines, grades, thickness and typical sections shown on the plans. This work includes producing, weighing, transporting, placing and compacting the plant mix; furnishing aggregate, asphalt binder, anti -strip additive and all other materials for the plant mix; furnishing and applying tack coat as specified; furnishing scales; maintaining the course until final acceptance of the project; making any repairs or corrections to the course that may become necessary; providing and conducting QC as specified in Section 609; and surface testing of the completed pavement. The design requirements fo r the various mix types are given in Section 610 for dense -graded mix types, Section 650 for OGFC , Section 652 for PADC and Section 661 for UBWC . Perform all activities in accordance with the Department’s Asphalt Quality Management System (QMS) Manual in effect on the date of contract advertisement Provide and conduct the QC and required testing for acceptance of the asphalt mixture in accordance with Section 609. Define “warm mix asphalt (WMA) ” as additives or processes that allow a reduction in the temper ature at which asphalt mixtures are produced and placed. Use only NCDOT approved WMA additives listed on the NCDOT APL maintained by the Materials and Tests Unit.

610-2 Materials

Refer to Division 10. Item Section Anti-Strip Additives 1020 -8 Asphalt Binder, Performance Grade 1020 -2 Coarse Aggregate 1012 -1(B) Fine Aggregate 1012 -1(C) Mineral Filler 1012 -1(D) Reclaimed Asphalt Pavement (RAP) 1012 -1(F) Reclaimed Asphalt Shingles (RAS) 1012 -1(E) Silicone 1020 -9

6-16 610-3 Composition of Mixtures (Mix Design and Job Mix Formula )

610-4 for the mix type. For recycled mix tures , the virgin binder Performance Grade (PG)

grade to be used is specified in Table 6 10-5 for the mix type based on the recycled binder replacement percentage (RBR%). If the Contractor w ishes to submit mix designs containing recycled material amounts exceeding the specified maximums, additional testing will be required to verify the Performance Grade (PG) of the reclaimed binder. Also, the Contractor has the option to have additional testing performed to determine if the mix can be approved using a virgin binder grade different than specified in Table 610- 5. The Engineer will determine if the binder grade is acceptable for use based on the test data submitted with the mix design. If the mix design is acceptable, the Engineer will establish and approve the grade and percentage of virgin asphalt binder to be used. If a change in the source of RAP or RAS be made, a new mix design and JMF may be required in accordance with Article 1012 -1. Samples of the completed recycled mixture may be taken by the Department on a random basis and the recovered asphalt binder will be tested in accordance wit h Article 1020 -2. If the grading is determined to be a value other than required for the specified mix type, the Engineer may require the Contractor to

6-17 adjust any combination of the grade, the percentage of additional asphalt binder or the

blend of reclai med material to bring the grade to the specified value.

6-18 being produced conform with specification requirements. When a change in sources of

aggregate materials is to be made, a new mix design and JMF will be required before the new mixture is produced. When a change in sources of RAP or RAS material is to be made, a new JMF is required and a new mix design may be required. When unsatisfactory results or other conditions make it necessary, the Engineer may revoke the existing JMF or establish a new JMF . TABLE 610-2 AGGREGATE GRADATION CRITERIA (Percent Passing Control Points) Standard Sieves (mm) Mix Type (Nominal Max. Aggregate Size) 4.75 mm 9.5 mmA 19.0 mm 25.0 mm Min Max Min Max Min Max Min Max 50.0 - - - - - - - - 37.5 - - - - - - 100 - 25.0 - - - - 100 - 90.0 100 19.0 - - - - 90.0 100 - 90.0 12.5 100 - 100 - - 90.0 - - 9.50 95.0 100 90.0 100 - - - - 4.75 90.0 100 - 90.0 - - - - 2.36 - - 32.0B 67.0B 23.0 49.0 19.0 45.0 1.18 30.0 60.0 - - - - - - 0.075 6.0 12.0 4.0 8.0 3.0 8.0 3.0 7.0

6-19 Table 610 -4

MAXIMUM RECYCLED BINDER REPLACEMENT PERCENTAGE (RBR %) Recycled Material Intermediate & Base Mixes Surface Mixes Mixes Using PG 76 -22 RAS 23% 20% 18% RAP or RAP/RAS Combination 45% 40% 18% TABLE 610 -5 BINDER GRADE REQUIREMENTS (BASED ON RBR%) Mix Type %RBR ≤ 20% 21% ≤ %RBR ≤ 30% %RBR > 30% S4.75A, S9.5B , S9.5C, I19.0C, B25.0C PG 64-22 PG 64 -22A PG 58-28 S9.5D , OGFC PG 76 -22B n/a n/a

610-4 Weather, Temperature and Seasonal Limitations for

PRODUCING AND PLACING ASPHALT MIXTURES Do not produce or place asphalt mixtures during rainy weather, when the subgrade or base course is frozen or when the moisture on the surface to be paved would prevent proper bond. Do not place asphalt material when the air or surface temperatures, meas ured at the location of the paving operation away from artificial heat, do not meet Table 610 -6. Do not place surface course material that is to be the final layer of pavement between December 15 and March 16 of the next year if it is 1 inch or greater in thickness , or between November 15 and April 1 of the next year if it is less than 1 inch in thickness, unless otherwise approved by the Engineer . As an exception to the above, when in any day's operations the placement of a layer of asphalt base course material or intermediate material 2 inches or greater in thickness has started, it may continue until the temperature drops to 32°F. Do not place plant mix base course that will not be covered with surface or intermediate course during the same calendar year or within 15 days of placement if the plant mix is placed in January or February. Failure by the Contractor to cover the plant mix as required above will result in the Engineer notifying the Contractor in writing to cover the plant mix with a sand seal . Apply the sand seal in accordance with Section 660, except that Articles 660-3 and

660-12 will not apply. In the event the Contractor fails to apply the sand seal within 72 hours

of receipt of such notice, the Engineer may proceed to have such work per formed with Department forces and equipment.

6-20 Table 610-6

PLACEMENT TEMPERATURES FOR ASPHALT Asphalt Concrete Mix Type Minimum Surface and Air Temperature B25.0C 35°F I19.0C 35°F S4.75A, S9.5B, S9.5C 40°FA S9.5D 50°F

610-5 Asphalt Mixture Production

Use plants that are either of the batch mixing, continuous mixing or drum mixing type, and so designed, equipped and operated that the weighing, proportioning and mixing of the materials will result in a uniform and satisfactory asphalt mixture meeting these specifications . All plants shall conform to requirements of Sections 5 and 6 of the Asphalt QMS Manual . Before production of the mix, stockpile aggregates for a sufficient period of time to facilitate the drainage of free moisture. Keep the different aggregate sizes separated until they have been delivered to the cold feeders. Keep the separate stockpiles readil y accessible for sampling. When mineral filler is required in the mix, feed or weigh- in separately from the other aggregates. Introduce the asphalt binder and other additives, when required, into the mixture at the amounts and percentages specified by the JMF . No working tolerance will be allowed. Introduce the hot and dry aggregates , mineral filler , and recycled materials , in amounts and at temperatures such that the mixture produced is within the production control limits of Subarticle 609- 6(D) . Provide a positive means of controlling mixing time to obtain complete and uniform coating of the aggregate particles and thorough distribution of the asphalt binder throughout the aggregate. Produce the mixture at the asphalt plant within ±25 °F of the JMF mix temperature. The temperature of the mixture, when discharged from the mixer, shall not exceed 350° F. All asphalt plants shall be certified by the Department. Certification is effective from the date of issuance and is non -expiring subject to continued compliance. The Department will check the plant on an annual basis or as deemed necessary by the Engineer. Any plant that is relocated, modified or changes ownership shall be recertified before use. Any completely automatically controlled asphalt plant that, due to the basic design of the plant, does not meet all these specifications for conventional batch mixing, continuous mixing or drum mixing may be use d on a project by project basis provided a uniformly consistent mix meeting all mix requirements can be produced and the plant has been approved in writing by the Department . Any asphalt plant that cannot consistently produce a high quality mix meeting these specifications will be in non- compliance with these s pecifications and may have its certification revoked. Upon a malfunction of required automatic equipment on a batch mixing plant, the plant may continue to operate manually for the following 2 consecutive working days, provided acceptable mixture is being produced. When a malfunction of required automatic equipment on a drum mixer or continuous plant occurs, manual operati on of the plant will not be allowed except that if, in the opinion of the Engineer, an emergency traffic condition exists, the plant may be allowed to operate manually until the unsafe traffic condition is corrected. All mix produced by manual operation w ill be subject to Section 609.

6-21 610-6 Hot Mix Storage Systems

When a storage system is used, provide a system capable of conveying the mix from the plant to the storage bin and storing the mix without a loss in temperature, segregation or oxidation of the mix. Limit storage time to the ability of the storage system to maintain the mix within the specification requirements. Material may be stored in storage bins without an appro ved heating system for no more than 24 hours. Provide a continuous type or skip bucket type conveyor system. Enclose continuous type conveyors so that the mix temperature is maintained within specification requirements. Provide a system designed in such manner as to prevent segregation of the mix during discharge from the conveyor into the bins and equipped with discharge gates that will not cause segregation of the mix while loading the mix into trucks.

610-7 Hauling of Asphalt Mixture

Transport the mixture from the mixing plant to the point of use in vehicles that have tight, clean, smooth beds approved by the Department, that have been sprayed with an approved release agent material to prevent the mixture from adhering to the beds. Remove excess release agent before loading. Cover each load of mixture with a solid, waterproof tarp constructed of canvas, vinyl, or other suitable material. Provide a 3/8 inch to 5/8 inch diame ter hole on each side of the vehicle body near the center of the body and above the bed of the vehicle for the purpose of inserting a thermometer. Assure temperature of the mixture immediately before discharge from the hauling vehicle is within a tolerance of ±25°F of the specified JMF mix temperature.

610-8 Spreading and Finishing

Apply tack coat in accordance with Section 605. Mixtures produced simultaneously from different plant sources cannot be intermingled by hauling to the same paver on the roadway unless the mixtures are being produced from the same material sources and same JMF . As referenced in Section 9.6.3 of the Asphalt QMS Manual , use the automatic screed controls on the paver to control the longitudinal profile. Where approved by the Engineer, the Contractor has the option to use either a fixed or mobile string line. Perform this work in accordance with and using e quipment meeting Section 9 of the Asphalt QMS Manual. Use a material transfer vehicle (MTV) when placing all asphalt concrete plant mix pavements which require the use of asphalt binder grade PG 76 -22 and for all types of OGFC, unless otherwise approved by the Engineer . Use a MTV for all surface mix regardless of binder grade on Interstate s, US Routes , NC Routes (primary routes) that have 4 or more lanes and are median divided. Where required above, use the MTV when placing all full width travel lanes and collector lanes . Use MTV for all ramps , loops , and Y-lines that have 4 or more lanes and are median divided , and all full width acceleration lanes, full width deceleration lanes , and full width turn la nes that are greater than 1,000 f eet in length . Use a MTV meeting Section 9.5(E) of the Asphalt QMS Manual. Place asphalt concrete base course material in trench sections with asphalt pavement spreaders made for the purpose or with other equipment approved by the Engineer. Request t he Engineer to waive the requirement for use of pavers for spreading and finishing where irregularities or obstacles make their use impractical. Spread, rake and lute the mixture by hand methods or other approved methods in these areas. Operate the paver as continuously as possible. Pave intersections, auxiliary lanes and other irregular areas after the main line roadway has been paved, unless otherwise approved by the

6-22 Engineer . Place a wedge course at locations ahead of the paving operation as required by the

Engineer. Repair any damage caused by hauling equipment across structures at no additional cost to the Department.

610-9 Compa Ction

Immediately after the asphalt mixture has been spread, struck off and surface and edge irregularities adjusted, thoroughly and uniformly compact the pavement. Compact the mix to the required degree of compaction for the type of mixture being placed. Provide sufficient number and weight of rollers, except as noted, to compa ct the mixture to the required density while it is still in a workable condition. Obtain approval of equipment used in compaction from the Engineer before use. Where uniform density is not being obtained throughout the depth of the layer of material being tested, change the type and/or weight of the compaction equipment as necessary to achieve uniform density even though such equipment has been previously approved. Compact all final wearing surfaces, except OGFC , using a minimum of two steel-wheel tandem rollers, unless otherwise approved by the Engineer . Pneumatic -tire rollers with two tandem axles and smooth tread tires may be used for intermediate rolling. Limit rolling for OGFC to one coverage with a tandem steel -wheel roller weighing a maximum of 10 tons, with additional rolling limited to one coverage with the roller where necessary to improve the riding surface. Steel -wheel tandem vibratory rollers specifically designed for the compaction of asphalt pavements may be used on all layers 1 inch or grea ter in thickness during the breakdown and intermediate rolling phase. Do not operate vibratory rollers in the vibratory mode during the finish rolling phase on any mix type or pavement course, OGFC or on PADC . When vibratory rollers are used, use rollers that have variable amplitude and frequency capabilities and that are designed specifically for asphalt pavement compaction. Provide rollers equipped with controls that automatically disengage the vibration mechanism before the roller stops when being used in the vibratory mode. The Engineer may prohibit or restrict the use of vibratory rollers where damage to the pavement being placed, the underlying pavement structure, bridges, drainage structures, utilities or other facilities is likely to occur or is ev ident. Do not use rolling equipment that results in excessive crushing of the aggregate or excessive displacement of the mixture. In areas inaccessible to standard rolling equipment, thoroughly compact the mixture by the use of hand tampers, hand operated mechanical tampers, small rollers or other methods approved by the Engineer . Use rollers that are in good condition and capable of being reversed without backlash to compact the mixture. Operate rollers with the drive wheels nearest the paver and at uniform speeds slow enough to avoid displacement of the mixture. Equip steel -whee l rollers with wetting devices that will prevent the mixture from sticking to the roller wheels. Begin compaction of the material immediately after the material is spread and shaped to the required width and depth. Carry out compaction in such a manner as to obtain uniform density over the entire section. Perform compaction rolling at the maximum temperature at which the mix will support the rollers without moving horizontally. Complete the compaction (including both intermediate rolling) before the mixt ure cooling below a workable temperature. Perform finish rolling to remove roller marks resulting from the compaction rolling operations.

6-23 610-10 Density Requirements

TABLE 610-7 DENSITY REQUIREMENTS Mix Type Minimum % G mm (Maximum Specific Gravity) S4.75A 85.0A S9.5B 90.0 S9.5C, S9.5D, I19.0C, B25. 0C 92.0

610-11 Joints

6-24 610-12 Surface Requirements and Acceptance

Construct pavements using quality- paving practices as detailed herein. Construct the pavement surface smooth and true to the plan grade and cross slope. Immediately correct any defective areas with satisfactory material compacted to conform with the surrounding ar ea. Pavement imperfections resulting from unsatisfactory workmanship such as segregation, improper longitudinal joint placement or alignment , non-uniform edge alignment or excessive pavement repairs will be unsatisfactory . Pavement imperfections will be e valuated for acceptance in accordance with Article 105 -3. When directed by the Engineer due to unsatisfactory laydown or workmanship, operate under the limited production procedures. Limited production for unsatisfactory laydown is defined as being restri cted to the production, placement, compaction and final surface testing (if applicable) of a sufficient quantity of mix necessary to construct only 2, 500 f eet of pavement at the laydown width. Remain on limited production until such time as satisfactory la ydown results are obtained or until three consecutive 2 ,500 feet sections have been attempted without achieving satisfactory laydown results. If the Contractor fails to achieve satisfactory laydown results after three consecutive 2 ,500 feet sections have been attempted, cease production of that mix type until such time as the cause of the unsatisfactory laydown results can be determined. As an exception, the Engineer may grant approval to produce a different mix design of the same mix type if the cause is related to mix problems rather than laydown procedures. Mix placed under the limited production procedures for unsatisfactory laydown or workmanship will be evaluated for acceptance in accordance with Article 1 05-3. Each pavement layer will be tested by the Contractor and the Engineer using a 10 foot stationary straightedge furnished by the Contractor. Any location on the pavement selected by the Department shall be tested as well as all transverse joints. Apply the straightedge parallel to the centerline of the surface. Do not exceed 1/8 inch variation of the surface being tested from the edge of the straightedge between any two contact points. Correct areas found to exceed this tolerance by removal of the defective work and replacement with new material, unless other corrective measures are permitted. Provide the work and materials required in the correction of defective work.

610-13 Final Surface Testing An D Acceptance

On portions of this project where the typical section requires two or more layers of new pavement, perform smoothness acceptance testing of the longitudinal profile of the finished pavement surface using either an Inertial Profiler or a North Carolina Hearne Straightedge (Model No. 1). Final surface testing is not required on ramps, loops and turn lanes. Use an Inertial Profiler (Option 1) to perform smoothness acceptance testing of the longitudinal profile of the f inished pavement surface . Furnish an inertial profiler(s) necessary to perform this work. Maintain responsibility for all costs relat ed to the procurement, handling, and maintenance of these devices. Furnish and operate the Hearne straightedge (Option 2) to determine and record the longitudinal profile of the pavement on a continuous graph. Before beginning any paving operations, the Contractor shall select one of the above options and submit documentation to the Engineer on the selected option for smoothness acceptance.

6-25 Use testing and recording software to produce electronic inertial road profiles in a format

compat ible with the latest version of FHWA’s ProVAL ( Profile Viewing and Analysis ) software . The Inertial Profiler shall be calibrated and verified in accordance with the most current version of AASHTO M 328. Provide certification documentation that the profi ler meets AASHTO M 328 to the Engineer before the first day the Inertial Profiler is used on the project. Configure the profiler to record the actual elevation of the pavement surface. Do not use the profiler’s internal IRI calculation mode. The profil e data shall be filtered with a 300 feet Butterworth high- pass filter . The interval at which relative profile elevations are reported shall be 1 inch. Provide IRI data in accordance with most current version of ASTM E1926. Use personnel trained to recor d and evaluate IRI data. Provide a n Inertial Profiler Operator that has been certified by the Department ’s Profiler and Operat or Certification Program as administered by the Materials and Tests Unit . Provide the user selected Inertial Profiler settings to the Engineer for the project records. In the presence of the Engineer, at the beginning of each day’s data collection, perform a block test to verify the Inertial Profiler’s ability to accurately co llect elevation data is met and perform bounce test to verify that the Inertial Profiler’s accelerometers are performing correctly. Remove all objects and foreign material on the pavement surface prior to longitudinal pavement profile testing. In the presence of th e Engineer, o perate the profiler at any speed as per the manufacturer’s recommendations to collect valid data. Operate the Inertial Profiler in the direction of the final traffic pattern. Collect IRI data from both wheel paths during the same run. Define a “wheel path ” as the 3 f eet from the edge of the travel lane. MRI values are the average of the IRI values from both wheel paths. When using an inertial profiler that collects a single trace per pass, take care to ensure that the measur ements from each trace in a travel lane start and stop at the same longitudinal locations. Unless otherwise specified, multiple runs are not necessary for data collection. Operate the automatic triggering method at all times unless impractical. Areas excluded from testing by the profiler may be tested using a 10-foot straightedge in accordance with

Article 610 — 12. The profiler sh all reach the intended operating speed bef ore entering the

test section. The runup and runout distances should be sufficient to obtain the intended operating speed and to slow down after testing is completed. Divide the pavement surface for the project into sections which represent a continuous placement (i.e. the start of the project to bridge, intersection to intersection). Ter minate a section 50 f eet before a bridge approach, railroad track, or similar interruption. (Separate into 0.10 -mile sections). The evaluation of the profiles will be performed on a section basis. A section is 0.10 mile of a single pavement lane . For any section, which is less than 0.10 mile in length, the applicable pay adjustment incentive will be prorated on the basis of the actual length. Mark the limits of structures and other special areas to be excluded from testing using the profiler’s e vent identifier such that the exact locations can be extracted from the profile data file during processing. Unless otherwise authorized by the Engineer, perform all smoothness testing in the presence of the Engineer. Perform smoothness tests on the finished surface of the completed project or at the completion of a major stage of construction as approved by

Article 105 — 3.

Any density lot not meeting minimum density requirements detailed in Table 610-7 will be evaluated for acceptance in accordance with Article 105 -3. If the lot is determined not to be acceptable, the mix will be removed and replaced with mix meeting and compacted to the requirement of these s pecifications .

Article 105 — 3. This acceptance process will apply to all asphalt produced or placed and will

continue until the Engineer determines a history of quality asphalt production and placement is reestablished. Furnishing asphalt binder will be paid as provided in Article 620 -4 for Asphalt Binder for Plant Mix for each grade required. Provide the work and materials required in the correction of defective work or sand seal base course as required at no cost to the Department. If the Engineer has such work perform ed with Department forces and equipment, the cost of such work performed by Department forces will be deducted from monies due or to become due to the Contractor. No direct payment will be made for final surface testing covered by this section. Payment at the contract unit prices for the various items covered by those sections of the s pecifications directly applicable to the work constructed will be full compensation for all work covered by

Article 610 — 13 including, but not limited to, performing testing in accordance with this

specification , any corrective work required as a result of this testing and any additional traffic control as may be necessary.