145 SECTION 401 PLANTMIX BITUMINOUS PAVEMENTS — GENERAL DESCRIPTION
401.01.01 General. These specifications include general requirements that are applicable to all types of
bituminous pavements of the plantmix type, irrespective of gradation of aggregate, kind and amount of bituminous material, or pavement use. Deviations from these general requirements will be indicated in the specific requirement for each type. This work consists of constructing one or more courses of bituminous mixture on the prepared foundation. MATERIALS
401.02.01 General. Material shall conform to the following Sections and Subsection:
Bituminous Materials ................................ ................................ ................................ ................................ .............................. Section 703 Aggregates for Bituminous Courses ................................ ................................ ................................ ................................ ....... Secti on 705 Commercial Mineral Filler ................................ ................................ ................................ ................................ ........ Subsection 705.03.03 Engineering Fabrics ................................ ................................ ................................ ................................ ............................... Section 731
401.02.02 Composition of Mixtures. Compose the bituminous plantmix of a mixture of aggregate, mineral
filler, and bituminous material. Size, uniformly grade, and combine the several aggregate fractions in such proportions that the resulting mixture meets the grading requirements of the job -mix formula. Do not commence paving or coldmilling operations until the following requirements have been complied with:
a.An approved mix design conforming to the requirements of this Subsection and Section 705 is received from the Department’s Materials Division. Mix Design Requirements (Plantmix and Premixed Bituminous Surface Aggregates): TEST TEST METHOD REQUIREMENTS Percent Air Voids of Compacted Bituminous Mixture (Types 2 and 3) AASHTO T269 * 4% Percent Air Voids of Compacted Bituminous Mixture (Type 2C) AASHTO T269 * 4% Percent Air Voids of Compacted Bituminous Mixture (Types 2 and 3) (Premixed) AASHTO T269 3 to 9% Stabilometer Value (Type 2) Nev. T303 35 Min . Stabilometer Value (Type 2C) Nev. T303 37 Min. Stabilometer Value (Type 3) Nev. T303 30 Min. Indirect Tensile Strength (Unconditioned) (Types 2 and 2C, except with PG 76 -22NV or PG 76 -22NVTR Asphalt) Nev. T341 448 kPa (65 psi) Min. Indirect Tensile Strength (Unconditioned) (Types 2 and 2C with PG 76 -22NV or PG 76 -22NVTR Asphalt) Nev. T341 689 kPa (100 psi) Min. Indirect Tensile Strength (Unconditioned) (Type 3) Nev. T341 400 kPa (58 psi) Min. Indirect Tensile Strength (Retained Strength) Nev. T341 70% Min. Voids in Mineral Aggregate (Types 2 and 2C Plantmix Aggregate) Nev. T338 12 to 22% * The mix design percent air void requirement may be adjusted by the Department to obtain passing values for other mix design requirements. In addition, the mixture design will be evaluated per Nevada Test Method No. Nev. T760. Mixture designs not meeting this requirement may be rejected.
b.Based upon the approved mix design, submit a written proposed job -mix formula for use by the Engineer in setting the job -mix to be used. For metric unit contracts, provide the proposed job -mix formula in metric units or both metric and English units. For English unit contracts, provide the proposed job -mix formula in English units or both English and metric units. Identify the asphalt cement supplier and shipping point in the job-mix formula. Include in the proposed formula definite single values for:
1.The percentage of aggregate passing each specified sieve.
2.The p ercentage of bitumen (bitumen ratio) to be added (to 0.1%), by dry weight of aggregate.
3.The temperature of the mixture leaving the mixer.
4.The minimum temperature of the mixture in the windrow or in the hopper of the paver .
5.The percentage of each aggregate bin used. (Bin percentages of less than 5% will not be allowed.) 401 PLANTMIX BITUMINOUS PAVEMENTS — GENERAL 146 The job -mix formula with the allowable tolerances shown herein shall conform to Section 705. A job -mix formula with single values for 1, 2, 3, 4, and 5 above will be determined and notification will be given in writing. This job -mix formula shall be in effect until modified in writing by the Engineer. Furnish mixture conforming to the job -mix formula, within the following range of tolerances: Aggregate passin g the 4.75 mm (No. 4) and larger sieves ................................ ................................ ................................ ........ ± 7% Aggregate passing the 2.36 mm to 150 μm (No. 8 to No. 100) sieves ................................ ................................ ....................... ± 4% Aggregate passing the 75 μm (No. 200) sieve ................................ ................................ ................................ ........................... ± 2% Bitumen ratio ................................ ................................ ................................ ................................ ...... ± 0.4% dry mass of aggregate Temperature leaving the mixer ................................ ................................ ................................ ................................ .. ± 11 °C (20 °F) Job-mix formula (1) shall reflect the bitumen ratio recommended by the approved mix design . Consistently produce a mixture with a bitumen ratio at the target value. Do not use the above operational tolerance as a means to alter the bitumen ratio target value. If the aggregates and asphalt cement submitted for a bituminous mix design produces a mixture exhibiting critical properties, see Note 1 below, be responsible for deciding whether a mixture can be produced which consistently meets project specification requirements, see Note 2 below. If electing to use a mix design that yields a critical mix, proceed and place the field trial mixture to be subjected to testing. If no satisfactory recommendation can be made by the Engineer from the test re sults of the field trial mixture , a new bituminous mix design will be required and a suspension of paving operations will be required until a new mix design is approved. Working days will continue to be charged. If the test results are satisfactory, the p aving may continue, however, the mixture will be monitored to assure that the project specification requirements are consistently met, see Note 2 below. Note 1: A critical mixture is one where there is a narrow range in the bitumen ratio in which project specification requirements are met for Stabilometer Value and Percent Air Voids of Compacted Bituminous Mixture (being a single point value or values in the acceptable range that do not allow for a ±0.4% fluctuation from the target value in bitumen ratio and still meet Stabilometer Value and Percent Air Voids requirements). If the range in the bitumen ratio, where Stabilometer Value and Percent Air Voids specification requirements are met, is 0.7% or less, the mixture will be reported as “critical” and the above listed criteria shall be met before its use on the project. Note 2: If two consecutive behind the paver samples (field samples) or 25% of the material sampled and tested, on a rolling 10 samples, fail to meet specification requirements for Stabilome ter Value and/or Percent Air Voids, the paving operations will be shut down. Submit a plan outlining corrective measures to alleviate the failing material, and receive approval before any further paving. Working days will not be suspended during any such s hutdown. (Rolling 10 samples indicates that only the preceding 10 samples will be counted in the analysis for consideration of failure, not the entire set of samples.) On the first day of bituminous mix production for each dense -graded mix design, produce one field trial mixture conforming to job -mix formula (1) during a maximum of 4 hours of operation. Complete all work by 1:00 p.m. Produce the mixture at the medium speed used during plant calibration. Place the mixture at an approved location. Suspend pr oduction of bituminous mix for a maximum of 3 working days or until all test results, except for Indirect Tensile Strength (Unconditioned) and Indirect Tensile Strength (Retained Strength), are available. Working days will not be charged during the 3 worki ng day suspension. Acceptance of the field trial mixture will be based on tests results meeting the requirements of this Subsection with the aggregate gradation within the job -mix ranges given and the in -place densities meeting the requirements of Subsect ion 402.03.06. When test results of the field trial mixture do not meet the requirements, additional field trial mixtures may be required and the required tests performed during one additional maximum 3 working day suspension or a new mix design may be re quired. Field trial mixtures not meeting the requirements will be addressed in accordance with Subsection 105.03. PLANTMIX BITUMINOUS PAVEMENTS — GENERAL 401 147 A revised job -mix formula (if applicable) will be provided based on the results of the tests performed on the field trial mixture. The ta rget bitumen ratio will be selected, based on meeting the specifications for Stabilometer Value , Percent Air Voids of Compacted Bituminous Mixtures , and aggregate gradation. Establish a new approved mix design and a new job -mix formula for any change in material sources. Changes include, but are not limited to, aggregate source, aggregate production method (crushing, screening, washing, or handling), asphalt supplier , asphalt shipping point , asphalt formulation, and method or rate of mineral filler additi on. Each approved mix design is valid for the calendar year in which it was performed. Establish a new approved mix design and a new job -mix formula if plantmix production continues or resumes after January 1 of the following year. When unsatisfactory resu lts make it necessary, the Engineer may establish a new job -mix formula and give notification in writing. The final plantmix product placed on the roadway shall comply with the approved mixture design, and the following project control requirements: TEST TEST METHOD REQUIREMENTS Percent Air Voids of Compacted Bituminous Mixture (Types 2 and 3) AASHTO T269 3 to 6% Percent Air Voids of Compacted Bituminous Mixture (Type 2C) AASHTO T269 3 to 6% Percent Air Voids of Compacted Bituminous Mixture (Types 2 and 3) (Premixed) AASHTO T269 3 to 9% Stabilometer Value (Type 2) Nev. T303 35 Min. Stabilometer Value (Type 2C) Nev. T303 37 Min. Stabilometer Value (Type 3) Nev. T303 30 Min. Indirect Tensile Strength (Unconditioned) (Types 2 and 2C except with PG 76 -22NV or PG 76 -22NVTR Asphalt) Nev. T341 448 kPa (65 psi) Min. Indirect Tensile Strength (Unconditioned) (Types 2 and 2C with PG 76 -22NV or PG 76 -22NVTR Asphalt) Nev. T341 689 kPa (100 psi) Min. Indirect Tensile Strength (Unconditioned) (Type 3) Nev. T341 400 kPa (58 psi) Min. Indirect Tensile Strength (Retained Strength) Nev. T341 70% Min. Final plantmix product placed on the roadway not conforming to the requirements specified herein will be assessed demerits according to the following schedu le. See Subsection 109.02, where demerits will be evaluated for damages sustained by reason of any noncompliance. TEST REQUIREMENT REJECTION LIMIT DEMERITS (a) Indirect Tensile Strength (Unconditioned) (Types 2 and 2C except with PG 76 -22NV or PG 76-22NVTR Asphalt) 448 kPa (65 psi) Min. 345 kPa (50 psi) Min. (b) Indirect Tensile Strength (Unconditioned) (Types 2 and 2C with PG 76 -22NV or PG 76 -22NVTR Asphalt) 689 kPa (100 psi) Min. 586 kPa (85 psi) Min. (b) Indirect Tensile Strength (Unconditioned) (Type 3) 400 kPa (58 psi) Min. 296 kPa (43 psi) Min. (b) Indirect Tensile Strength (Retained Strength ) 70% Min. 55% Min. (b)
a.Demerits may be reduced or waived if bituminous material does not conform to Section 703. Demerits apply only to the material produced on the shift the material was sampled.
b.Demerits will be assessed on a prorated basis by dividing the difference betw een the REQUIREMENT and the TEST RESULT by the difference between the REQUIREMENT and the REJECTION LIMIT and multiplying by 21. The demerit value will be rounded down to t he nearest whole demerit. Cease production if two consecutive test results or 40% o f the total test results fail for Indirect Tensile Strength (Unconditioned) or Indirect Tensile Strength (Retained Strength). Evaluate available information and determine the likely cause or causes of the problem and propose a change. Additional lime will not be allowed to increase Indirect Tensile Strength (Unconditioned). Approval will not be given if the proposed change will be a detriment to other properties of the mix. Do not resume production until proposed changes have been approved. A new mix design may be required. The maximum temperature of the mixture at the plant when using asphalt cement shall be 177 °C (350 °F). The minimum temperature of the mixture at the paver when using asphalt cement s with an “NV” or “NVTR” designation shall be 149 °C (300 °F). The minimum temperature of the mixture at the paver for all other asphalt cements shall be 121 °C (250 °F). In no case shall the temperature of the mixture leaving the plant and arriving at the paver drop more than 11 °C (20 °F) for plantmix s urfaces mixtures and 8 °C (15 °F) for plantmix open -graded mixtures when using asphalt cement . 401 PLANTMIX BITUMINOUS PAVEMENTS — GENERAL 148 When using cutback asphalt, the temperature of the bituminous material just before mixing, the completed mixture discharged from the mixer, and the completed mix ture in the hauling vehicle just before leaving the plant shall conform to the following: GRADE and TYPE MC or SC BITUMINOUS MATERIAL AND MIXTURES Minimum °C (°F) Maximum °C (°F) 70, 70NV 3000 35 (95) 57 (135) 74 (165) 93 (200) 60 (140) 79 (175) 96 (205) 116 (240) In no case shall the temperature of the mixture leaving the plant and arriving at the paver drop more than 11 °C (20 °F) when using cutback asphalt. Furnish five 3.75 L (1 gal) samples of each grade of asphalt cement or cutback asphalt specified in the contract not less than 20 working days before starting paving operations. Furnish samples of asphalt cement in paint can type containers. Also furnish a sample of the aggregates not less than 20 working days before star ting paving operations. Do not submit samples for bituminous mix designs until a minimum of 4,500 metric tons (5,000 tons) or 25% of the required contract quantity is produced proportionately in stockpile, whichever is less. Obtain samples from the produce d stockpiles. The Engineer will obtain these samples or witness the Contractor obtaining them. See Subsection 106.04. Bituminous material may be conditionally accepted at the source. In lieu of furnishing samples of asphalt cement and aggregates for a mi xture design , a mix design which has been previously performed and approved by the Department’s Materials Division may be submitted for approval . If the submitted plantmix bituminous surface aggregate and asphalt cement meet the individual specification requirements, but fail to meet the mix design requirements when combined, a one time suspension of up to 10 working days may be allowed, when deemed necessary, for resubmittal and retesting for an acceptable mix design. If, at anytime during production, th e bituminous mixture does not meet the requirements of this Section, make the necessary modification to the bitumen ratio, at own expense, in order to bring the mixture into compliance. In the event that the project control requirements are being met, and the Engineer chooses to direct an increase in the bitumen ratio above the target value resulting from the field trial mixtures, additional compensation will be provided according to Subsection 402.05.01. When additional mineral filler, above the minimum sp ecified, is required to meet the requirements for Indirect Tensile Strength (Retained Strength), Test Method No. Nev. T341, additional compensation will be provided according to Subsection 402.05.01. CONSTRUCTION
401.03.01 Bituminous Mixing Plant. (a) Ge neral. Maintain the storage yard in a neat and orderly manner.
Make stockpiles, readily accessible for sampling. Store asphalt cement in tanks separate and apart from dryer burner fuel. Tanks with separate compartments may be used only if the compartments do not have a common wall. Provide viewing port between compartments.
b.Burner Fuel and Burner. Limit fuel used for heating aggregates to the following types; natural gas, liqu efied natural gas, fuel oil (ASTM D396, Grades No. 1 and No. 2), butane, propane, diesel fuel oil (ASTM D975, Grades No. 1 -D and No. 2 -D). Certify that burner fuels comply with the foregoing and provide Certificate of Compliance conforming to Subsection 106.05. The burner used for heating the aggregate shall achieve complete combustion of the approved fuel and not leave any fuel residue that will adhere to the heated aggregate.
c.Mixing Plants. Use mixing plants conforming to the following:
1.Requirements for All Plants. Use mixing plants of sufficient capacity to adequately handle the proposed PLANTMIX BITUMINOUS PAVEMENTS — GENERAL 401 149 bituminous construction. Provide 48 hours notice before beginning mixing plant calibrations. For job -site plants, provide a copy of the current NDEP per mit covering the limitations of the mixing plant production capacity not less than 48 hours before beginning calibrations. Once an approved mix design has been received, calibrate mixing plants prior to plantmix operations, whenever a plant is moved, no l ess than once a year, and any other time as directed. Do not begin plantmix production until calibration procedures have been completed. Submit calibration results on NDOT Form 040-038 Plant Calibration Works heet, or similar form, for approval. Do not oper ate outside the parameters of the plant calibration limits during production. For mobile plants, produce a quantity of bituminous mixture that provides a representative sample to prove the gradation and bitumen ratio conform to the approved job -mix formul a. A mobile plant is defined as a facility that has been in place, calibrated, and producing mixtures for one year or less. The requirement to produce this quantity of bituminous mixture may be waived if requested in writing and approved. Once the plant c alibration has been received and approved, allow a minimum of 24 hours prior to beginning production for calibration of the Department's ignition furnace.
a.Equipment for Preparation of Bituminous Material. Equip tanks for the storage of bituminous mate rial to heat and hold the material at the required temperatures. Accomplish the heating by steam coils, electricity, or other approved means so that no flame shall be in contact with the tank. Design the circulating system for the bituminous material to as sure proper and continuous circulation during the operating period. Make provision for measuring and sampling storage tanks.
b.Drier. Use a drier or driers which continuously agitate the aggregate during the heating and drying process.
c.Thermometric Equipment. Fix an armored thermometer of adequate range in temperature reading in the bituminous feed line at a suitable location near the charging valve at the mixer unit. Replacement of any thermometer by an approved temperature -recording apparatus for better regulation of the temperature of aggregates may be required. Use thermometers that record in degrees Celsius (Fahrenheit for English unit contracts).
d.Smoke and Dust Control. Install satisfactory precipitation devices, or use other methods whic h will meet local conditions, city, county, and State laws pertinent to air pollution.
e.Truck Scales. Except as allowed in Subsection 401.04.01, provide approved platform or silo scales conforming to Subsection 109.01.
f.Safety Requirements. Provide adequate and safe stairways to the mixer platform and sampling points and place guarded ladders to other plant units at all points where accessibility to plant operations is required. Provide access to the top of truck bodies by a platform that will allow mixture temperatures to be taken and visual inspection of the mix. Provide a hoist or pull ey system to raise scale calibration equipment, sampling equipment, and other similar equipment from the ground to the mixer platform and return. Thoroughly guard and protect gears, pulleys, chains, sprockets, and other dangerous moving parts. Maintain ample and unobstructed passage at all times in and around the truck loading areas. Keep this area free from drippings from the mixing platform.
g.Baghouse Fines. If introducing baghouse fines into the mix, draw the material from a storage facility in which the material is kept in a uniform free flowing condition. Supply the baghouse fines for delivery to the plant from a positive weighing device which is interlocked, (rate of baghouse fines introduction shall automatically vary with the rate of the aggregate feeder) to the flow of each aggregate feeder. Equip the baghouse feeder to provide continuous uniform flow within 5% of the actual mass. Calibrate the baghouse fi nes feeder at two different speeds (the lowest and highest speed of anticipated operation) in relation to the speed of the aggregate feed. Provide an approved calibrated scale or weigh metering device to determine the actual mass of baghouse fines for each test. Furnish a test box having a sufficient capacity to perform the calibration testing. Calibrate the baghouse fines feed so the masses shown on the metering device are within ± 5% of the weighed mass. In a continuous mix and/or dryer drum plant add th e baghouse fines at the asphalt feed line to insure a uniform mix. 401 PLANTMIX BITUMINOUS PAVEMENTS — GENERAL 150 In batch plants add the baghouse fines by the use of a separate bin. Introduce the baghouse fines at an approved point, at a percentage determined by the Department’s Materials Division, and not exceeding 2% by dry mass of the aggregate. Consider baghouse fines as part of the aggregate, and not as a mineral filler.
h.Controls. Do not operate mixing plants with manual controls when equipped with computer controls.
i.Metering Devices. Provide means to verify material totals prior to introduction into the mixer.
2.Requirements for Batching Plants.
a.Plant Scales. Provide scales accurate to 0.5% of the maximum load that may be required. Design poises to be locked in any position to prevent unauthorized change or position. In lieu of truck scales, an approved automatic printer system which will print the masses of the material delivered may be used, provided the system is used in conjunction with an approved automatic batching and mix ing control system. Document such masses by a weigh ticket for each load.
b.Feeder for Drier. Provide the plant with accurate mechanical means for uniformly feeding the aggregate into the drier so that uniform production and uniform temperature will be obtained.
c.Screens. Use plant screens capable of screening all aggregates to the specified sizes and proportions when the aggregate is proportioned after the drying operations. Plant screens may be eliminated when proportioning is done before the drying process and the aggregate is proportioned according to subparagraph 4. b., of this Subsection and prepared according to the first paragraph of Subsection
401.03 08.
d.Bins. Provide storage bins of sufficient capacity to supply the mixer when it i s operating at full capacity. Arrange bins to assure separate and adequate storage of appropriate fractions of the mineral aggregates. Provide separate dry storage for mineral filler when used and equip the plant to feed such material into the mixer. Provi de each bin with overflow pipes, of such size and at such locations as to prevent backing up of material into other compartments or bins. Provide each compartment with its own individual outlet gate, constructed to cut off quickly and completely . Construct bins so that samples can be readily obtained.
e.Weigh Box or Hopper. Include a means for accurately weighing each size of aggregate in a weigh box or hopper suspended on scales and of ample size to hold a full batch without hand raking or running over. The gate shall close tightly so that no material is allowed to leak into the mixer while a batch is being weighed.
f.Bituminous Control Unit. Provide satisfactory means, either by weighing or metering, for obtaining the proper amount of bituminous mate rial in the mix within the tolerance specified. Provide means for checking the quantity or rate of flow of bituminous material into the mixer.
g.Bituminous Control. Use equipment to measure the bituminous material accurately to ±0.5%. The bituminous mat erial bucket shall be a nontilting type with a loose sheet metal cover. Use a discharge opening or spray bar with a length of not less than 75% of the length of the mixer and which discharges directly into the mixer. Adequately heat the bituminous material bucket, its discharge valve or valves, and spray bar. Efficiently drain steam jackets, if used, and construct connections so that they will not interfere with the efficient operation of the bituminous scales. Provide bituminous material bucket with a capa city of at least 15% in excess of the mass of bituminous material required in any batch. Provide adequately heated quick -acting, nondrip, charging valve located directly over the bituminous material bucket. Measure bituminous material by means of springle ss dial scales or metering devices. Provide springless dial scales with a capacity of not more than 450 kg (1,000 lb) in 1 kg (2 lb) gradations. Provide the indicator dial with a capacity of at least 15% in excess of the quantity of bituminous material used in a batch. Construct the controls so that they may be locked at any dial setting and will automatically reset to that reading after the addition of bituminous material to each batch. Place the dial in full view of the mixer operator. Automatically cont rol the flow of bituminous material so that it will begin when the dry mixing period is over. Discharge all of the bituminous material required for one batch in not more than 15 seconds after the flow has started. Provide the size and spacing of the spray bar openings for a uniform application of bituminous material the full length of the mixer. Provide the section of the bituminous line between the PLANTMIX BITUMINOUS PAVEMENTS — GENERAL 401 151 charging valve and the spray bar with a valve and outlet for checking the meter when a metering device is substituted for a bituminous material bucket.
h.Mixer. Provide the batch mixer of a twin pugmill type, with steam jackets, or heat by other approved means and capable of producing uniform mixtures within the specified tolerances. Equip it with a sufficient number of paddles or blades set in proper order and operated at such speed as to produce a properly and uniformly mixed batch. Do not exceed 25 mm (1 in.) clearance of the paddles or blades from all fixed and moving parts. Do not use badly worn or defecti ve paddles or blades in mixing operations.
i.Control of Mixing Time. Equip the mixer with an accurate time lock to control the operations of a complete mixing cycle. The time lock shall lock the weigh box gate after the charging of the mixer until the c losing of the mixer gate at the completion of the cycle. The time lock shall lock the bituminous material bucket throughout the dry mixing period and shall lock the mixer gates throughout the dry and wet mixing periods. The dry mixing period is defined as the interval of time between the opening of the weigh box gate and the start of introduction of bituminous material. The wet mixing period is the interval of the time between the start of introduction of bituminous material and the opening of the mixer gat e. Equip the mixer with a timing device which will indicate by a definite audible or visual signal the expiration of the mixing period. The device shall measure the time of mixing within an accuracy of 2 seconds. Provide and maintain a suitable automatic device in proper working condition for counting the number of batches. When the aggregates and the bituminous material have been combined, mix the entire mass in an approved mixer. Continue the mixing until a homogeneous mixture with a uniform coating is achieved. Do not exceed output rate greater than the manufacturer’s capacity rating.
3.Requirements for Continuous Mixing Plants (Proportioned After Drying).
a.Feeder for Drier. Provide the plant with accurate mechanical means for uniformly feeding the aggregate into the drier so that uniform production and uniform temperature will be obtained.
b.Screens. Provide plant screens capable of screening all aggregates to the specified sizes and proportions.
c.Bins. Provide storage bins of sufficient capacity to supply the mixer when it is operating at full capacity. Arrange bins to assure separate and adequate storage of appropriate fractions of the mineral aggregates. Provide separate dry storage for mineral filler when used and equip the plant to fe ed such material into the mixer. Provide each bin with overflow pipes, of such size and at such locations as to prevent backing up of material into other compartments or bins. Provide each compartment with its individual outlet gate. Construct bins so that samples can be readily obtained. Equip bins with adequate telltale devices to indicate the position of the aggregates in the bins at the lower quarter points.
d.Aggregate Proportioning. Provide a means for accurately proportioning each size of aggregate after the drying operation. Provide a mechanical feeder mounted under each compartment bin. Each compartment bin shall have an accurately controlled individual gate for volumetrically measuring the material drawn from each compartment. The feeding orific e shall be rectangular with one dimension adjustable by positive means. Provide indicators for each gate to show the respective gate opening. Provide a meter for determining the rate of each feeder, or a revolution counter.
e.Mass Calibration of Aggreg ate. Provide a means for calibration of each aggregate feeder by weighing test samples. Provide accurate scales and test boxes for this mass calibration.
f.Bitumen Metering Device. Introduce the bituminous material into the mixer through a positive disp lacement metering device. Equip this metering device with a ready means of varying the bituminous material delivery rate.
g.Synchronization of Aggregate Feed and Bituminous Material Feed. Provide satisfactory means to afford a positive interlocking cont rol between the flow of each feeder and the flow of bituminous material. The interlocking control shall indicate a visible or audible signal when the level of material in any one feeder approaches the strike off capacity of the feed gate, or shut the plant down. 401 PLANTMIX BITUMINOUS PAVEMENTS — GENERAL 152 h. Mixer. Include a continuous mixer of an approved type, adequately heated and capable of producing a uniform mixture within the job -mix tolerances. Use paddles adjustable for angular position on the shafts and reversible to retard the flow of th e mix. The mixer shall have a manufacturer’s plate giving the net volumetric contents of the mixer at the several heights inscribed on a permanent gage. Provide bin graphs showing the rate of feed of aggregate in metric tons (tons) per hour.
i.Surge Bin s. Equip the plant with an approved surge bin at the discharge. Provide surge bin in excess of 18.1 metric tons (20 tons), and equip with an approved surge batcher or other approved method that will prevent segregation of the bituminous mixture as it is be ing discharged into the hauling vehicle.
4.Requirements of Continuous Mixing Plant s (Proportioned Before Drying).
a.Aggregate Stockpiles. The first paragraph of Subsection 401.03.08 shall apply.
b.Aggregate Proportioning. Include a means for accurately proportioning each size of aggregate before the drying operation. Separate each compartment bin by a vertical divider of adequate height to prevent aggregate spillover from adjacent bins. In addition, provide each bin with an accurate method of regulating and measuring the material being drawn from the bin. Provide indicators for each bin to show respective feed rates.
c.Mass Calibration of Aggregate. Prior to the mass calibration of the aggregate weigh belt, calibrate each aggregate feeder bin . Once the feeder bins have been calibrated, supply a graph of each aggregate feeder bin showing the speed of the belt versus metric tons (tons) per hour of material. Calibrate the aggregate weigh belt at three different speeds, (lowest, medium, and the h ighest speed of anticipated operation). Provide platform scales with a Certificate of Inspection as required in Subsection
109.01 in the same pit as the plant. Furnish a test box having a minimum capacity to perform the calibration
testing. Nine metric ton s (10 tons) will be the minimum amount required for a valid test. Calibrate the aggregate feed so the masses shown on the metering device are within ±1% of the actual mass as weighed on the certified platform scales. The difference of the three runs shall be within 1% of each other.
d.Bitumen Metering Device and Calibration. Introduce the bituminous material into the mixer through a positive displacement metering device. Equip this metering device with a ready means of varying the bituminous delivery rate . Calibrate the bitumen metering device at 3 different speeds (lowest, medium, and the highest speed of anticipated operation) in relation to the aggregate feed using the bitumen ratio set forth in the approved mix design. Provide platform scales with a Ce rtificate of Inspection as required in Subsection 109.01 in the same pit as the plant. Use a vessel for calibration having a minimum capacity to perform the calibration testing. A minimum of 3,785 L (1,000 gal) will be the required amount of bitumen for a valid test. If approved, other certified devices may be allowed. Calibrate the bitumen feed so the masses shown on the metering device are within ±0.5% of the actual mass as weighed on the certified platform scales.
e.Synchronization of Aggregate Feed a nd Bituminous Material Feed. Provide satisfactory means to afford a positive interlocking control between the flow of each feeder and the flow of bituminous material. The interlocking control shall indicate a visible or audible signal when the level of mat erial in any one feeder approaches the strike off capacity of the feed gate, or shut the plant down.
f.Mixer. Include a continuous mixer of an approved type, adequately heated and capable of producing a uniform mixture within the job -mix tolerances. Use paddles adjustable for angular position on the shafts and reversible to retard the flow of the mix. Retard the flow of material through the mixer by reversing a minimum of the last two rows of paddles or providing a material dam. The mixer shall have a ma nufacturer’s plate giving the net volumetric contents of the mixer at the several heights inscribed on a permanent gage. Provide charts showing the rate of feed of aggregate per minute for the aggregate being used.
g.Surge Bins. Equip the plant with an approved surge bin at the discharge. Provide surge bin in excess of 18.1 metric tons (20 tons) capacity, and equip with an approved surge batcher or other approved method that will prevent segregation of the bituminous mixture as it is being discharged int o the hauling vehicle.
h.Screens. Provide plant screens capable of screening all aggregates to the specified sizes and proportions.
5.Requirements for Dryer Drum Mixing Plants. The requirements of subparagraph 4 of this Subsection shall apply, with th e exception of subparagraph 4. f. PLANTMIX BITUMINOUS PAVEMENTS — GENERAL 401 153 a. Mixer. Include a mixing device which will obtain a homogeneous mixture with a uniform coating. The mixing output shall not exceed the manufacturer’s capacity rating.
401.03.02 Hauling Equipment. Use trucks for hauling bituminous mixture with tight, clean, and smooth metal
beds which may be thinly coated with a minimum amount of one of the asphalt release agents listed in the QPL to prevent the mixture from adhering to the truck beds. Do not use diesel or kerosene. Discharge the bituminous mixture from the surge -storage system directly into the hauling vehicle.
401.03.03 Pavers. Use pavers that are self contained, power -propelled units, provided with an activated screed
or strike -off assembly, heated if necessary, a nd capable of spreading and finishing courses of bituminous mixture in lane and shoulder widths applicable to the specified typical section and thicknesses shown on the plans. Equip pavers with a receiving hopper having sufficient capacity for a uniform s preading operation. Equip the hopper with a distribution system to place the mixture uniformly in front of the screed. Equip the screed with automatic controls which will make adjustments in both transverse and longitudinal direction. The external longitu dinal reference devices used to pick up grade information for the automatic sensing control shall conform to the following: When picking up grade information from an underlying base, the external longitudinal reference device shall be a floating beam at l east 9 m (30 ft) long or an 8 m (27 ft) non -contact averaging ski with a minimum of 4 sensors. When picking up grade information from an adjacent compacted pavement course or a concrete surface, the external longitudinal reference device shall be a floati ng beam or a non -contact averaging ski with a minimum of 2 sensors. Either referencing device shall be at least 3 m (10 ft) in length. When using a floating beam to pick up grade information, place the sensing device in the middle third of the floating be am. A non -contact sensor may be used to pick up grade information from a newly placed adjacent compacted course only when approved. Should the automatic controls fail to function properly, finishing the half shift with manual controls may be approved. Do not resume until the controls are repaired.
401.03.04 Rollers. Rollers shall meet the following requirements:
a.Breakdown rollers shall be a 2 axle tandem steel wheeled weighing not less than 9.1 metric tons (10 tons) and capable of rolling with or wi thout vibration.
b.Pneumatic tired rollers shall weigh not less than 9.1 metric tons (10 tons) and be equipped with pneumatic tires of equal size and diameter mounted on 2 axles attached to a rigid frame equipped with a loading platform or body suitable for ballast loading. The minimum width between the outer edge of the outside tires on a given axle is 1.5 m (60 in.). Use tires with satisfactory treads. Space the tires on the rear axle so that the entire gap between adjacent tires on the front axle will be covered by the tread of the rear tires. Uniformly inflate the tires so that the air pressure in the tires will not vary more than 35 kPa (5 psi). Use the tire manufacturer’s recommended inflation pressure. Use a minimum ti re size of 185 mm x 375 mm (7.5 in. x 15 in.), 4 ply. Fully skirt the roller with rigid material to within 25 mm (1 in.) of pavement surface.
c.The finish roller shall be a 2 axle tandem steel wheeled weighing not less than 7.2 metric tons (8 tons).
401.03.05 Weather Limitations. Do not place plantmix bituminous surface when frozen materials are present
in the base. Do not place plantmix bituminous surface during rain or snowfall or when the roadway is wet. Place plantmix bituminous surface when the atmospheric temperature is a bove those listed below: Compacted Thickness Atmospheric Temperature Less than 25 mm (1 in.) ................................ ................................ ................................ ................................ ................ 13 °C (55 °F) 25 mm to 50 mm (1 to 2 in.) ................................ ................................ ................................ ................................ ........... 7 °C (45 °F) Greater than 50 mm (2 in.) ................................ ................................ ................................ ................................ ............. 2 °C (35 °F) 401 PLANTMIX BITUMINOUS PAVEMENTS — GENERAL 154 Place plantmix bituminous surface only when the surface temperature is above 10 °C (50 °F). Place open -graded plantmix surface only when the atmospheric temperature and the pavement surface temperature are above 15 °C (60 °F).
401.03.06 Preparation of Ex isting Surface. When the surface of the existing pavement or old base is
irregular, bring it to a uniform grade and cross section as directed. Paint contact surface of curbing, gutters, manholes, and other structures with a thin, uniform coating of emulsi fied asphalt before the bituminous mixture is placed.
401.03.07 Preparation of Bituminous Materials. Heat the bituminous material to the specified temperature in
a manner that will avoid local overheating and provide a continuous supply of the bituminous material to the mixer at a uniform temperature at all times. Maintain asphalt cements with an “NV” or “NVTR” designation in storage tanks at a minimum temperature of 149 °C (300 °F) during the production of bituminous mixtures. Continuously circulate or m oderately agitate the asphalt in the storage tanks during the production of bituminous mixtures.
401.03.08 Preparation of Aggregates. Separate aggregates proportioned before the heating and drying
process, into two general sizes: (1) that portion of the material having a minimum of 80% passing a 4.75 mm (No. 4) sieve, and (2) that portion of the material having a minimum of 80% retained on a 4.75 mm (No. 4) sieve. Maintain the material within these limits with a uniformity of ± 5%. Store each portion of t he material separately. When moving the aggregate from storage to compartment bins, use any method which will not cause segregation, degradation, or combinations of aggregate which fail to meet the specified gradation requirements. Do not commence plantmix operations until a minimum of 4,500 metric tons (5,000 tons) combined has been proportionately stockpiled and marinated, unless the tonnage required is less than 4,500 metric tons (5,000 tons). Screen aggregates proportioned immediately after the heating and drying process into a minimum of two fractions if minus 12.5 mm (1/2 in.) aggregate is used, and into a minimum of three fractions when larger sized aggregate is used. Convey the screened material to separate compartments ready for proportioning, and mixing with bituminous material. Do not commence plantmix operations until a minimum of 4,500 metric tons (5,000 tons) has been proportionately stockpiled and marinated, unless the tonnage required is less than 4,500 metric tons (5,000 tons). When the req uired tonnage is more than 4,500 metric tons (5,000 tons), then maintain a minimum of 4,500 metric tons (5,000 tons) of material proportionately stockpiled and marinated until such time as 4,500 metric tons (5,000 tons) or less are needed to complete the p lantmix operations. Place the aggregates in the cold feed proportioning bins directly from the stockpile. Do not charge the cold feed bins from the crushing plant. The plasticity index for any individual stockpile for use in the plantmix products before m arination shall not exceed 10. Correct the plasticity problem if the plasticity index of any individual stockpile exceeds 10 before marinating the material. Do not blend with sand to lower the plasticity index.
a.Mineral Filler Feeding. Add mineral filler to all plantmix bituminous aggregates according to the Marination Method.
1.Marination Method. Wet cure the coarse aggregates with mineral filler at a minimum rate of 1% of the mass of dry aggregate. Wet cure the fine aggregates with mineral filler at a minimum rate of 2% of the mass of the dry aggregate. The exact rate of application shall be as approved. Marinate (wet cure) the aggregates in stockpiles for a minimum of 48 hours. Fine aggregate stockpiles have a minimum of 50% passing the 4.75 mm (No. 4) sieve. All other stockpiles will be treated as coarse aggregate. Marinate stockpiles individually. Do not use the marination method process to combine stockpiles. Use the wet cured aggregate in the stockpile within 60 days. Before t he introduction of the mineral filler, add sufficient moisture by way of spray bars at the aggregate bins to bring the aggregate to a moisture content where enough free surface moisture is available to thoroughly wet the aggregate and activate the lime. Th e actual amount of moisture shall be as approved. After the addition of water and mineral filler, mix the aggregate using a horizontal twin -shaft pugmill with a minimum effective mixing length of 1.5 m (5 ft). Use mixing paddles which are adjustable for an gular position on the shaft to permit altering of the mixing pattern or retarding the flow to insure that the aggregate is thoroughly coated with mineral filler. PLANTMIX BITUMINOUS PAVEMENTS — GENERAL 401 155 Do not extend the volume of material in the pugmill above the vertical position of the blade t ips. Retard the flow of material through the pugmill by reversing a minimum of the last two rows of paddles or providing a material dam. Draw mineral filler from a storage facility in which the mineral filler is agitated by air or other means to keep it i n a uniform free flowing condition. Deliver the mineral filler to the mixer from a positive weighing device which is interlocked, (actuate electric driven feeders from the same circuit) to the flow of each aggregate feed. Equip the mineral filler feeder to provide a continuous uniform flow to within 5% of the required amount. Provide an aggregate feed and weight system which meets the requirements of Subsection 401.03.01. Calibration of the aggregate weigh belt shall conform to Subsection 401.03.01 (4.c) w ith the exception that marinated material is not required. Calibrate the mineral filler feeder at two different speeds (the lowest and highest speed of anticipated operation) in relation to the speed of the aggregate feed. Use a target of 1% mineral fille r for the low speed metric tons (tons) per hour and 2% mineral filler for the high speed metric tons (tons) per hour. Provide an approved calibrated scale or weigh metering device to determine the actual mass of mineral filler for each test. Furnish a test box having a sufficient capacity to perform the calibration testing. Calibrate the mineral filler feed so the masses shown on the metering device are within ± 5% of the weighed mass.
2.Cold Feed Method. The Cold Feed Method is not allowed for use unless specifically stated in the Special Provisions. When the Cold Feed Method is allowed for use, add hydrated lime (hereinafter referred to as mineral filler) to all plantmix bituminous aggregates at the rate of not less than 1% nor more than 2.5% of the mass of the dry aggregate. The exact rate of application shall be as approved. Draw mineral filler from a storage facility in which the mineral filler is agitated by air or other means to keep it in a uniform free flowing condition. Deliver the mineral filler to the mixer from a positive weighing device which is interlocked, (actuate electric driven feeders from the same circuit) to the flow of each aggregate feeder. Equip the mineral filler feeder to provide continuous uniform flow to within 5% of the require d amount. In continuous mix and drum dryer plants, add mineral filler to the aggregate after the aggregate is proportioned. In batch plants, add the mineral filler to the aggregate before drying. Before the introduction of the mineral filler , add suffic ient moisture by way of spray bars at the aggregate bins to bring the aggregate to a moisture content where enough free surface moisture is available to thoroughly wet the aggregate and activate the lime. The actual amount of moisture shall be as approved. After the addition of water and mineral filler, mix the aggregate using a horizontal twin -shaft pugmill with a minimum effective mixing length of 1.5 m (5 ft). Use mixing paddles which are adjustable for angular position on the shaft to permit altering of the mixing pattern or retarding the flow to insure that the aggregate is thoroughly coated with mineral filler. Do not extend the volume of material in the pugmill above the vertical position of the blade tips. Retard the flow of material through the pugm ill by reversing a minimum of the last two rows of paddles or providing a material dam. Directly introduce the completed mixture into the hotplant. Do not stockpile the completed mixture. Interlock the moisture control valve with the hotplant control room so the moisture control valve is automatically turned off when the cold feed belts are shut off. The control valve shall also turn on automatically when the cold feed belts are activated.
401.03.09 Mixing. Do not exceed a moisture content of 1% in the bi tuminous mixture just behind the paver as
determined by Test Methods No. Nev. T112 (Method A) or T306. Take satisfactory corrective action before resuming plantmix operations should the aggregate contain excessive moisture when heated within the temperatur e limits. Combine the dried aggregate in the mixer in the amount of each fraction of aggregates required to meet the job-mix formula. Measure and gage the bituminous mixture and introduce into the mixer in the amount specified by the job -mix formula. When the aggregates and the bituminous material have been combined, mix the entire mass in an approved mixer. Continue mixing until homogeneity and a uniform coating are achieved. Do not exceed the manufacturer’s capacity rating for the output rate. Should t he mixture at the discharge of the mixer, at the plant, in the haul vehicle, or in place, show a nonuniform or nonhomogeneous mix, show an excess or deficiency of bitumen, show injury or damage due to burning or 401 PLANTMIX BITUMINOUS PAVEMENTS — GENERAL 156 overheating, show an improper combination of aggregates, show a separation of the bituminous material from the aggregates, or fail to conform to specification requirements, it will be rejected. Provide an adequate access point at the mixer discharge for sampling. If the unsatisfactory mix, as referr ed to above, is still in the truck, dispose of the mix, or if it has been placed, remove, dispose, and replace the mix. Immediate control of the bitumen ratio for bituminous mixtures will be accomplished by testing the completed mixture according to Test Method No. Nev. T761. For the job -mix formula values listed in Subsection 401.02.02, take corrective measures at the plant before production continues if two consecutive test results indicate the material is out of tolerance. If three consecutive test results for any one job -mix formula property are outside of tolerance, cease production until test results or other information satisfactorily indicate that the next material to be produced will meet the specified values. When directed, produce a sufficien t quantity of bituminous mixture to prove the material is within specification prior to beginning full production.
401.03.10 Spreading and Finishing. Place each course of the plantmix bituminous surface full width. Any
portion of the course may be advance d only to the extent of one day’s operation before beginning work on a succeeding width. Complete the course to its full plan width before any general longitudinal advancement beyond the width first placed. Bring all portions of the course to as near the s ame point as practicable before suspending paving operations for more than one day, unless otherwise ordered. Dump the mixture on the prepared surface and spread with the spreading and finishing machine. If windrow pick -up equipment is used, make it capable of removing and loading all of the mixture deposited on the roadbed into the spreading and finishing machine. Do not turn hauling equipment in areas where such turning may result in tearing, gouging , or distortion of the edges of a previously laid pad of bituminous material. Immediately discontinue any turning causing such damage, and repair. Lay the mixture upon an approved surface, spread, strike off to grade and elevation established. Use bituminous pavers to distribute the mixture either over the entire width or over such partial width as may be practical. Regulate the forward rate of travel of the paving machine to a speed dependent upon the capacity of the mixing plant to furnish the mixture. Move the machine at a uniform rate with a minimum amount of stopping. On areas where irregularities or unavoidable obstacles make the use of mechanical spreading and finishing equipment impracticable, spread, rake, and lute the mixture by hand tools. For such areas, dump, spread, and screed the mixture to give the required compacted thickness.
401.03.11 Rolling. Thoroughly and uniformly compact the pavement by rolling.
Thoroughly compact the edges of pavements not accessible to conventional rollers with suitable types of tampers, plates, trench rollers , etc. Commence initial rolling at the lower edge and progress towards the highest portion of the roadbed. Perform rolling in a manner that avoids cracking, shoving, or displacement. Use rollers in good condition and capable of rolling and changing dire ction without adversely affecting the mat. Properly moisten the wheels of the rollers to prevent adhesion of the hot mix asphalt. Use clean water or asphalt release agents listed in Subsection 401.03.02 of the QPL. Perform all compactive rolling, defined as initial or intermediate, while the surface temperature of the mat is above 85 °C (185 °F). Complete finish rolling within the same day of placement of the plantmix bituminous surface while the surface temperature of the mat is above 68 °C (155 °F).
401.03.12 Joints. Place the bituminous material as continuously as possible. Do not pass rollers over the
unprotected end of a freshly laid mixture. PLANTMIX BITUMINOUS PAVEMENTS — GENERAL 401 157 (a) Longitudinal. Offset longitudinal construction joints of successive courses of bituminous pavement at l east 150 mm (6 in.). Place bituminous pavement so that any longitudinal joints constructed are within 300 mm (12 in.) of the final traffic lane lines. Do not construct two longitudinal joints within the same traffic lane.
b.Transverse. Expose the full depth of the layer and form a clean vertical edge. Place additional mixture to provide a 1:50 (50:1) transition on dense -graded plantmix bituminous surface. Remove transition material prior to continuing paving operations away from the transverse joint. No direct payment will be provided for this work. Place a brush coat of asphalt emulsion on contact surface of the joint before additional mixture is placed.
401.03.13 Surface Tolerances. Surface tolerances will be specified under the respective sections of
bituminous pavement.
401.03.14 Surfacing Miscellaneous Areas. Areas which may be included in this work are the surfacing of
road and driveway approaches, median strip areas, island areas, sidewalks, dikes (excluding plantmix shoulder dikes), gutters, gutter flares, ditches, downdrains, spillways, aprons at the end of drainage structures , and other designated areas outside the traveled way. Eliminate the 12.5 mm (1/2 in.) and larger aggregate and increase the bitumen ratio by not less than 1% by dry weight of aggregate over the dense -graded job -mix formula in the bituminous mixture placed in gutters, gutter flares, dikes, down drains, spillways, aprons at the end of drainage structures, and other designated areas outside the traveled way. A revise d job -mix formula is not required. The bituminous mixture placed in these miscellaneous areas, except for approaches, may be spread in one layer. Compact to the required lines, grades, and cross section.
401.03.15 Pavement Reinforcing Fabric . Deliver and store pavement reinforcing fabric according to the
manufacturer's recommendations. Do not store the fabric directly on the ground and keep the fabric in a dry covered condition free from dust, dirt, and moisture Prior to the commencement of fabric placement, have a representative from the fabric manufacturer provide an informational/training session to educate personnel on proper installation procedures and specifications, and ensure cooperation and understanding among the Department's inspectors and Contractor personnel. Attendance is mandatory for all personnel involved with the project including inspectors, consultants, and Contractor personnel. Give notification of the date, time, and location of the informatio nal/training session a minimum of 7 days prior to the scheduled date. The manufacturer's representative shall be on site for the first two days of the fabric installation, or longer at the discretion of the Engineer, and shall monitor the operation to ens ure proper installation. Prior to placing the fabric, assure that pavement is clean enough to provide significant adhesion to the fabric as approved by the Engineer and the manufacturer’s representative. If necessary, clean the pavement with a mechanical device by sweeping or vacuuming. If recommended by the manufacturer’s representative, apply a tack coat to the pavement surface prior to fabric placement at the application rate specified by the representative. The exact application rate shall be determin ed and adjusted by the representative. Apply additional tack coat as required to the fabric and underlying plantmix surface as necessary to bond the two plantmix layers together, as directed. Total tack coat application shall not exceed 0.45 L/m2 (0.10 gal /yd2). Prior to commencement of fabric placement, select an area on the shoulder of the pavement and conduct a pull test according to the fabric manufacturer's recommendation to assure adequate fabric adhesion to the pavement. Place the fabric when the p avement surface temperature is within the range as recommended by the fabric manufacturer’s representative. 401 PLANTMIX BITUMINOUS PAVEMENTS — GENERAL 158 Lay the fabric by mechanical means or by hand methods under sufficient tension to eliminate ripples, creases, and bubbles. Remove such irregulariti es by pulling the fabric tight or in extreme cases by cutting and overlaying the cut area with a fabric patch with an overlap as recommended by the fabric manufacturer’s representative. Lap transverse and longitudinal joints with an overlap as recommended by the fabric manufacturer’s representative. When laying fabric in multiple lanes, place fabric so that a minimum of 150 mm (6 in.) of fabric will extend beyond the edge of paving in order to ensure enough material for the required longitudinal overlap. Do not allow public traffic on the installed fabric. Ensure adequate adhesion of the fabric to the pavement prior to allowing construction traffic on the installed fabric. Make every effort to prevent damage to the fabric. Use care when turning or braking and allow construction traffic to travel on the installed fabric only in the direction of the paving operation. Keep the fabric clean of mud, dust, and other debris. Repair damaged sections or areas where foreign material has come between the surface and t he fabric. Remove damaged sections and foreign material that comes between the surface and the fabric by cutting the fabric and removing such material. Clean the surface and place a fabric patch per the fabric manufacturer's recommendation. Take care to in sure fabric placement is made as flat and smooth as possible. Do not place more fabric than can be covered by plantmix in the same shift. Cease all construction activities directly involving fabric placement and plantmix paving if slippage of the fabric o ccurs due to the elevated temperature of the roadway surface. Construction activities may resume only when the temperature of the roadway surface declines to the point at which it no longer causes slippage of the fabric.
401.03.16 Shoulder Dikes. Shape an d compact dikes with an extrusion machine or other equipment to the
required cross section. Eliminate the 12.5 mm (1/2 in.) and larger aggregate and increase the bitumen ratio by not less than 1% by dry weight of aggregate over the dense -graded job -mix fo rmula in the bituminous mixture placed in shoulder dikes. A revised job -mix formula is not required. METHOD OF MEASUREMENT
401.04.01 Measurement. Plantmix surfacing will be measured by the metric ton (ton) of completed mixture of
aggregate, asphalt, and mineral filler. Shoulder dikes will be measured by the linear meter (linear foot) for placing. Length will be determined from measurements taken along the top of the dikes. The quantities of bituminous mixture used to construct the dikes will be measured as set forth above. Plantmixing miscellaneous areas will be measured by the square meter (square yard) for placing. Areas to be included in such measurement shall be limited to those areas listed in the plans, plus or minus authorized changes. Areas will be measured one time only, without consideration of the number of lifts or types of bituminous mixtures involved. The quantities of bituminous mix ture used to pave the miscellaneous areas will be measured as set forth above. Pavement reinforcing fabric will be measured by the square meter (square yard) of surface area covered. No allowance will be made for material overlap. Batch masses will not b e permitted as a method of measurement unless the alternate provisions of Subsection
401.03 01, (c)2.a., are met, in which case the cumulative mass of all the acceptable batches will be used for
payment. BASIS OF PAYMENT
401.05.01 Payment. The accepted quantities of pavement reinforcing fabric, measured as provided above, will
be paid for at the contract price per unit of measurement for the pay item listed below that is shown in the proposal. Payment will be full compensation for the work prescribed in this Section. All other quantities, measured as provided above, will be paid for as provided in the respective sections for each type specified. Payment will be made under: Pay Item Pay Unit Pavement Reinforcing Fabric ................................ ................................ ................................ ....................... Square Meter (Square Yard) 159 SECTION 402 PLANTMIX BITUMINOUS SURFACE DESCRIPTION
402.01.01 General. This work consists of constructing one or more courses of dense-graded bituminous
pavement on a prepared base. MATERIALS
402.02.01 General. Material shall conform to the following Subsections:
General ................................................................................................................................................................... Subsection 401.02.01 Composition of Mixtures .......................................................................................................................................... Subsection 401.02.02
402.02.02 Recycled Asphalt Pavement. Recycled asphalt pavement (RAP) may replace 5 to 15%, by mass,
of the total aggregate in Type 2 or Type 2C plantmix bituminous mixtures. Individual bin percentages of RAP shall be 5% minimum. After the initial selection of the percentage of RAP to be used, changes to the percentage of RAP material will not be allowed without a new mix design. The RAP material shall not be contaminated with concrete, aggregate base, soil, or other objectionable material. The Department will evaluate the RAP and determine if the material will be allowed for use. Crush and process RAP in a manner that produces one or more stockpiles of uniform material that are 100% passing the 12.5 mm (1/2 in.) sieve. The RAP material will not require marination. Stockpile the RAP to be used in the production of bituminous plantmix for the Department separate from other RAP and virgin aggregate stockpiles. Take one informational sample of the RAP material for every 500 tons that is stockpiled. For each informational sample, test the RAP material for gradation, bitumen ratio, and extracted aggregate gradation. Recover aggregates from the RAP material by test method AASHTO T164. The results for bitumen ratio shall not vary more than 2% between any two results. Analyze the aggregate extracted from the RAP material for gradation by test method AASHTO T30. Submit the test results of the informational samples prior to sampling for a mix design. The results of the informational samples will be reviewed by the Department and will be used to accept the RAP submitted for the mix design. Testing personnel are required to be qualified in the Nevada Alliance of Quality Transportation Construction (NAQTC) Asphalt Extended Module which includes AASHTO T164 and AASHTO T30. Calibrate and interlock the system used to deliver the RAP to the mixer in accordance with Subsection
401.03 01.
If RAP is used, for test methods that require the material to be dried, allow an additional 24 hours for the completion of testing. If utilizing RAP, furnish samples of asphalt cement, aggregates, and RAP not less than 30 working days before starting paving operations. CONSTRUCTION
402.03.01 General. The construction requirements shall conform to Subsections 401.03.01 through 401.03.14,
inclusive, with the exceptions contained in the following Subsections.
402.03.02 Rollers. Use approved equipment for compaction of plantmix bituminous surface. Size rollers to
achieve the required results. Use at least two rollers, one steel wheeled and one pneumatic tired with each paver. Provide pneumatic tired rollers conforming to Subsection 401.03.04 (b).
Source: Nevada Standard Specifications for Road and Bridge Construction, 2014 Edition. Pages 151–164 of 610.