407.01 296 SECTION 407 – BITUMINOUS PLANT MIX PAVEMENTS (GENERAL)
407.01 Description ................................ ................................ ................... 296
407.02 Materials ................................ ................................ ...................... 297
407.03 Composition of Mixtures ................................ ............................. 298
407.04 Bituminous Mixing Plant ................................ ............................. 312
407.05 Hauling Equipment ................................ ................................ ...... 323
407.06 Bituminous Pavers and Material Transfer Devices ...................... 323
407.07 Rollers ................................ ................................ .......................... 325
407.08 Small Tools ................................ ................................ .................. 326
407.09 Weather Limitations ................................ ................................ ..... 326
407.10 Conditioning the Existing Surface ................................ ............... 328
407.11 Preparing the Bituminous Material ................................ .............. 328
407.12 Preparation of Aggregates ................................ ............................ 330
407.13 Mixing ................................ ................................ .......................... 330
407.14 Spreading and Finishing ................................ ............................... 331
407.15 Compaction ................................ ................................ .................. 333
407.16 Joints ................................ ................................ ............................ 338
407.17 Pavement S amples ................................ ................................ ....... 338
407.18 Surface Requirements ................................ ................................ .. 339
407.19 Method of Measurement ................................ .............................. 339
407.20 Basis of Payment ................................ ................................ .......... 341
DESCRIPTION
407.01 Description
This Section 407 is applicable to all types of bituminous pavements of the asphalt plant mix type as described in 307, 313, and 411. Deviations from these general requirements will be indicated in the specific requirements for each pavement type. This work consists of constructing one or more courses of bituminous mixture on a prepared foundation in accordance with this Section 407 and the specific requirements of the pavement type under contract . 407.02 297 MATERIALS
407.02 Materials
Provide materials as specified in: Aggregates ................................ ................................ .................. 903 Mineral Filler ................................ ................................ ......... 903.16 Bituminous Materials ................................ ................................ .. 904 Chemical Admixtures and Additives ................................ .. 921.06.B Separate aggregate into coarse and fine aggregate stockpiles. If stockpiling of coarse aggregat e causes segregation, separate into coarse and medium coarse stockpiles. Store each size and type of aggregate in a separate pile, bin, or stall. Maintain the storage yard in an orderly condition, clearing a walkway between stockpiles that are not separ ated by partitions. Make the stockpiles readily accessible for sampling. The Engineer will conditionally accept the mineral aggregate for quality in the stockpile at the producer’s site. The Engineer may conditionally accept the bituminous material at th e asphalt terminal. The Engineer will accept for aggregate gradation and asphalt cement content from hot bin samples or sample(s) taken from the completed mix at the asphalt plant after it has been loaded onto the trucks for transport to the Project. If anti-stripping additive, other than hydrated lime, meeting 921.06.B.1 is required, use approved in -line blending equipment, as specified in
407.04 A.6 , to add it at the mixing plant or inject it at the asphalt terminal.
Manufacture’s documentation that asphalt binders will continue to meet requirements listed in 904 after the anti -stripping additive is added shall be provided by the contractor with the mix design submittal. For mix designs submitted more than six months in advance, the documentation shall be resubmitted prior to use of the mix design with updated test results. If the resurfacing plans call for a Performance Grade (PG) asphalt mix with properties greater than that o f PG 64-22 and this is the only asphalt grade on the Project, the Contractor may use either the asphalt grade shown on the Plans or an asphalt grade equal to or better than PG 64 -22 for driveways and business entrances unless otherwise directed by the Engi neer. The Department will pay for this material at the same unit price as bid for the 407.03 298 asphalt or asphalt mix. Mark the material tickets “ FOR DRIVEWAYS AND BUSINESS ENTRANCES ONLY ” at the point of delivery. If using a warm mix asphalt additive meeting 921.06.B.3 , use approved blending equipment to add it at the mixing plant, or deliver it premixed with the asphalt cement. For 411-OGFC mixtures , include a stabilizing additive listed on the Department’s Qualified Products List (QPL). Do not use f iber pellets. Slag wool fiber or cellulose f iber shall be blown into the asphalt plant measured by a flow meter or sensing device that is accurate to within plus or minus 10% of the amount required. For batch plants, add fibers in to the pugmill or weigh hopper. For drum plants, place the fiber line 1 foot upstream of the asphalt binder line so that the fibers are captured by the asphalt binder before being expose d to high-velocity gases in the drum. The minimum additive for a slag wool fiber shall be 0.4% and the minimum for a cellulose fiber shall be 0.3% of the total mix . The addition of a stabilizing additive material (fiber) shall be included in the cost of the asphalt c ement.
407.03 Composition of Mixtures
A.General Develop a bituminous mixture composed of aggregate (coarse, fine, or mixtures thereof), mineral filler if required, anti -strip additive if required, and bituminous material. Ensure that the aggregate fractions are sized, uniformly graded, and combined in such proportions so that the resulting mixture will meet the grading and physical properties of the approved Job Mix Formula (JMF).
B.Gradation and Bitumin ous Material Requirement The requested aggregate gradation and bituminous material percentages shown on the JMF shall be within the design ranges specified in 903, 307, and 411, respectively. Establish a recommended asphalt cement content for all mixes , with the final optimum asphalt cement content to be determined by the Engineer.
C.Job Mix Formula (JMF)
1.General. At least 14 working days before the scheduled start of production of any asphaltic paving mixture, submit a proposed Job Mix Formula (JMF) and Laboratory Design in electronic form, 407.03 299 where applicable, prepared in accordance with the Marshall Method of Mix Design (Asphalt Institute, MS -2), as modified by the Department , or by Gyratory Compaction (AASHTO T 312). Regardless of which method is used, prepare trial blends with at least four different asphalt contents (at least two above the optimum and two below the optimum). When using the Marshall method of comp action, compact the specimens to 7 5 blows per side . When using the gyratory metho d of compaction, compact specimens to 65 gyrations. All 411-OGFC design procedures shall follow the most current version of National Asphalt Pavement Association (NAPA) Publication IS -115, “Design, Construction and Maintenance of Open-Graded Friction Courses” except where modified herein. Design the OGFC using a Marshall compaction hammer at 50 blows or a standard gyratory compactor at 50 gyrations. Provide the following in formation with JMF submittals:
a.The specific project on which the mixture will be used.
b.The source and description of all materials to be used in the mix.
c.The gradations and approximate proportions of the raw materials as intended to be combined in the pavi ng mixture.
d.A single percentage of the combined mineral aggregate passing each specified sieve. Plot the combined aggregate gradation on a gradation chart with sieve sizes raised to the 0.45 power to ensure a well graded mix.
e.The Loss on Ignition (LOI) re sults on the combined aggregate of the mixture used as a wearing course.
f.The Bulk Specific Gravity, Apparent Specific Gravity, and absorption on the combined mineral aggregate in the paving mixture (AASHTO T 84 and T 85).
g.The fractured face count and glass y particle count of the plus No. 4 material, if applicable. 407.03 300 h. A single percentage of asphalt by weight of total mix intended to be incorporated in the completed mixture.
i.The dosage rate and source of anti -stripping additive, if required, meeting the requirem ents of 921.06.B.1 , to be added to the asphalt.
j.The maximum specific gravity of the asphalt mixture (AASHTO T 209).
k.A single temperature at which the mixture is intended to be discharged from the plant.
l.Evidence that the comp leted mixture will conform to all physical requirements specified in 903.06 and 307.03.A or
903.11 and 411.03.B; however, for mixes designed acc ording
to AASHTO T 312, the stability and flow requirements will be waived and the resistance to rutting requirements for surface mixtures must be met.
m.The tensile strength ratio (TSR) indicating the stripping and moisture susceptibility characteristics of the mix.
n.To identify critical mixes and make appropriate adjustments, the mix design shall meet the required design properties for stability, flow, voids in mineral aggregate (VMA), and production void content as specified in 307.03 and 411.03 at the bitumen content range of Optimum Asphalt Cement plus or minus 0.25%. Establish t he laboratory mix and compaction temperatures for the JMF in accordance with Table 407.03-1. 407.03 301 Table 407.03-1: Laboratory Mix and Compaction Temperatures PG Binder Grade Lab Mix Temperature (°F) Lab Compaction Temperature (°F) 64-22, 67-22 Per temp./visc. Chart Per temp./visc. Chart 70-22 320 – 345 295 – 320 76-22 320 – 345 305 – 330 82-22 320 – 345 305 – 335 Perform a ny additional laboratory testing of the mix using the laboratory mix and compaction temperatures listed on the approved JMF, with a tolerance of plus or minus 5 °F for each temperature. A Certified Laboratory Technician shall prepare and sign the Laboratory Design. To be certified, the technician shall have completed the Marshall Method of Mix Design School conducted by the Department, including the written and lab performance testing.
2.Revision of J ob Mix Formula. The approved JMF shall remain in effect until the Engineer authorizes a change in writing. The Contractor, at any time after construction has started, may request that the JMF be revised, provided evidence is shown that the revision is ne cessary, and the revised aggregate gradation will meet all applicable gradation requirements. Submit a revised JMF if, during the test strip construction and mix design/production verification procedure, changes are made to the mixture to comply with the s pecified criteria. Provide a new design for any change in source of materials. Submit all requests for design mix adjustments, redesigns, and new design mixes in writing to the Engineer for approval.
3.Resistance to Plastic Flow. Include, with the submitt ed JMF, test data showing that the material as produced will meet 307.03.A or
411.03 B when tested according to AASHTO T 245. Determine the
bulk specific gravity of the laboratory compacted bitumin ous mixture (Marshall specimens) according to AASHTO T 166. Mixes 407.03 302 designed according to AASHTO T 312 are exempt from AASHTO T 245. For surface mixtures used on roads with greater than 5,000 ADT, designed with the gyratory compactor (AASHTO T 312), include sufficient raw materials (aggregate and asphalt cement) with the submitted JMF so that the Central Laboratory may conduct rut testing in accordance with AASHTO T 340 . The maximum allowable rut depth shall be 0.35 inches for roads with greater than or equal to 10,000 ADT and 0.40 inches for roads with 5,000 to 10,000 ADT. Base the percent voids in the total mix on the maximum specific gravity of the bituminous mixture (Rice Gravity) according to AASHTO T 209. Calculate the voids in mineral aggregate (VM A) using the effective specific gravity of the aggregates.
D.Contractor’s Quality Control
1.General. Assume responsibility for the quality of construction and materials incorporated in the Work. Provide and maintai n a quality control system that will provide reasonable assurance that all materials conform to specification requirements. Conduct all quality control sampling and testing according to the approved Quality Control Plan and the Department’s Policies on Sampling and Testing Procedures and Sampling of Asphalt Mixes for Verification of Laboratory Design. The requirements for the Contractor’s quality control sampling and testing will remain in effect until final Project acceptance.
2.Contractor Quality Control System. Develop, implement, and maintain a quality control system that will provide reasonable assurance that all materials and products submitted to the Department for acceptance conform to the specified requirements.
a.Quality Control Technician. Ensure that a Quality Control Technician, who is currently certified by the Department as a Certified Asphalt Plant Technician, is present at the asphalt plant during mix production. If the Department finds that the Quality Control Technician cannot perf orm as required by the position, the Department will revoke the certification and require replacement with a certified technician. 407.03 303 b. Documentation. Document all quality control procedures, inspections, and tests and make this information available for review by the Department throughout the life of the Contract. Maintain adequate records of all inspections and tests. The records shall indicate the nature and number of tests performed, the number and type of deficiencies found, and the nature of corrective action taken as appropriate. The Contractor’s documentation procedures will be subject to the review and approval of the Department before the start of the work and to compliance checks during progress of the work. Provide copies of all charts and rec ords documenting quality control tests and inspections to the Engineer on a daily basis.
c.Charts and Forms. Record all conforming and nonconforming inspections and test results on approved forms and charts, and keep these records current and complete. Maintain test results at the Contractor’s plant site laboratory and make such records available to the Engineer at all times during the performance of the work. Chart test results for the various materials and mixtures on forms that meet the Engineer’s requirements. Provide an example of each proposed chart and form to the Engineer. Supply all charts and forms to be used to record results.
d.Corrective Actions. Promptly correct all errors, equipment malfunctions, process changes, or other assignable causes that have resulted or could result in the submission of materials, products, and completed construction that do not conform to the specifications. If the Engineer finds that the Contractor is not controlling its process and is making no effort to take cor rective actions, the Engineer will require that plant operations be ceased until the Contractor can demonstrate that it can and will control the process.
e.Laboratories with Measuring and Testing Equipment. Provide a fully equipped laboratory at the production site as specified in 106.06. This facility may be permanent or portable. Furnish the laboratory with the necessary testing equipment and supplies for performing Contractor Quality Contr ol sampling and testing as well as Department Acceptance sampling and 407.03 304 testing. To assure accuracy, the Department will check the testing equipment periodically according to the Department’s Procedure for Qualified Laboratories.
f.Sampling and Testing. Sampling and testing methods and procedures to determine quality conformance of the materials and products shall be in accordance with 106.04. Address in the Quality Control Plan the taking of samples for material characteristics and the plotting of the test results on control charts.
g.Alternative Procedures. The Engineer may approve the use of alternative sampling methods, procedures, and inspection equipment if such procedures and equipment provide, as a minimum, the quality assu rance required by the Contract. Before applying such alternative procedures, describe them in a written proposal and demonstrate, for the Engineer’s approval, that their effectiveness is equal to or better than the Contract requirements.
h.Minimum Mixture Q uality Control Testing . During production of the mixture, provide material that conforms to the approved JMF. Perform testing on mixtures to confirm conformance to the acceptance criteria and the JMF as follows. Mixes with a project total of less than 1 ,000 tons are exempt from all verification testing requirements unless deemed necessary by the Engineer.
1.Start Up Testing . Produce 500 tons of mixture at the beginning of production of each mixture to confirm that the mixture meets the follow requirements :
a.All mix requirements are within the tolerance defined in Table 407.03 -2.
b.Gradation and Asphalt Content are within the tolerance for a 1.00 pay factor based on a single test per Table 407.20 -2. 407.03 305 c) The average density on the test strip meets the requirements for 100% payment per Table
407.15 1.
Sample mixture for startup testing from one of the first ten trucks loaded of any mixture to complete this testing. Provide a technician certified by the Department in Asphalt Mix Design to perform all start up testing. All testing shall be done under th e Department’s supervision. Present all test results to the Department for approval of the mix verification. If any of the above criteria fail verification, cease production. Make adjustments to the process and produce no more than 100 tons to retest the mixture. Once the mixture passes verification full production may proceed. If the retest fails, submit a modified JMF to the Engineer. All nonconforming mix produced during the test strip construction is subject to acceptance and pay adjustment or removal per 407.20. Table 407.03 -2: Mix Design Requirements Property Value Maximum Theoretical Gravity ± 0.025 of Mix Design Value Voids in Total Mix As noted for production in
307.03 and 411.03
Voids in Mineral Aggregate Minimum as noted in 307.03 and 411.03 Marshall Stability Minimum as noted in 307.03 and 411.03 Dust/Asphalt Ratio As noted in 307.03 and 411.03
2.Production Testing. Sample and perform testing for conformance of the mix to the JMF within the tolerances defined in Table 407.20 -2 on a 1000 ton maximum lot basis throughout production . Consider the process to be out of control and cease plant operations if test results f rom a single lot fall below the 0.90 pay factor limit or consecutive 407.03 306 tests fall below the 0.95 pay factor as specified in Table
407.20 2. Make adjustments to the process and produce no
more than 100 tons for testing purposes. If the retest fails, submit a modified JMF to the Engineer. The Department will not allow the project to resume unless some corrective action has been taken and documented. Once test results show results compliant with the 1.00 pay factor range full production may resume.
3.Volumetric Testing . On any project using modified asphalt cement, test all the mix design requirements per Table 407.03 -2 for each half day of production. Record all results on control charts made available to the department. If results fall outside the tolerance established in Table
407.03 2 then the following appl ies:
a.Resample and retest.
b.If the retest meets the criteria continue on without interruption.
c.If the retest fails to meet criteria, cease produc tion. Make adjustments to the process and produce no more than 100 tons for testing purposes. If this retest fails, submit a modified JMF to the Engineer. The Department will not allow resumption of the project unless some corrective action has been tak en and documented. Once compliance is achieved, resume full production.
3.Quality Control Plan. At the beginning of each paving season, submit in writing the proposed Quality Control Plan for the Engineer’s approval. Include in this plan the sampling, t esting, and inspection activities, and the anticipated frequencies of each, which the Contractor will follow to maintain process control. This Quality Control Plan shall apply to all Department contracts for the calendar year. If a change is made to the Quality Control Plan during the year, communicate such changes to the Regional Materials Supervisor. Refer to the recommended series of sampling, testing, and inspecting activities shown in Table 407.03 -3. 407.03 307 Table 407.03-3: Recommended Items for a Contractor Quality Control Plan
A.All Types of Plants
1.Stockpiles
a.Determine gradation of all incoming aggregates.
b.Inspect stockpiles for separation, contamination, segregation, etc.
c.Conduct a fractured face count when gravel is used as coarse aggregate.
d.Determine the percent of glassy particles in slag coarse aggregate.
e.Determine gradation and asphalt content of recycled asphalt pavement when used as a component material.
2.Cold Bins
a.Calibrate the cold gate settings.
b.Observe operation of cold fee d for uniformity.
c.Ensure that bins have proper dividers to prevent materials from spilling over into adjacent bins.
3.Dryer
a.Observe pyrometer for aggregate temperature control.
b.Observe efficiency of the burner.
c.Determine the percent dust coating on plus 4 ma terial.
d.Check dried aggregate for contamination due to incomplete combustion of fuel.
4.Hot Bins
a.Determine gradation of aggregates in each bin.
b.Determine theoretical combined grading.
5.Bituminous Mixture
a.Determine percent bitumen.
b.Determine mix gradation.
c.Check mix temperature.
d.Determine percent moisture in mix when recycled asphalt pavement is a component material.
e.Determine Loss -On-Ignition (LOI) of aggregates in mix where applicable.
f.Check the mix for uncoated aggregate.
g.Ensure that handling procedures do n ot contribute to segregation of the mix. 407.03 308 B. Batch Plants
1.Batch Weights – Determine percent used and weight to be pulled from each bin to assure compliance with the JMF.
2.Check mixing time (both dry and wet).
3.Check operations of weigh bucket and scales.
4.Document accuracy of all weighing and metering devices for:
a.Asphalt cement
b.Aggregate
c.Anti-strip additive
C.Drum Mixer Plant
1.Calibrate the cold feed and prepare a calibration chart for each cold gate.
2.Develop information for the synchronization of the aggre gate feed and the bituminous material feed.
3.Determine moisture content of aggregate being fed into dryer.
4.Determine the percent dust coating on dried plus 4 material.
5.Check dried aggregate for incomplete combustion of fuel.
6.Document accuracy of all weighing and metering devices for:
a.Asphalt cement
b.Aggregate
c.Anti-strip additive Consider the activities identified in Table 407.03 -3 to be normal activities necessary to control the production of asphalt concrete at an acceptable quality level. However, note that depending on the type of process or materials, some of the activities listed may not be necessary, and in other cases, additional activities may be required. The frequency of these activities will also vary with the process and the materials. When the process varies from the defined process average and variability targets, increase the frequency of these activities as necessary to restore proper conditions. Plot and keep up-to-date control charts for all Quality Control Sampling and Testing. P rovide control charts for the following: 407.03 309 (a) Extracted asphalt content
b.Mix gradation
c.Dust to asphalt ratio
d.Maximum theoretical gravity (when required)
e.Voids in total mix (when required)
f.Stability (when required) Post all current control charts in the asphalt lab where they can be seen. The Contractor is responsible for formulating all design mixes with the exception of plant mix seal coat mixes. No lab design is required for 307 Grading A, AS, and ACRL mixes. However, establish the anti-strip additive dosage rate and verify compatibility of mixture materials by the ten minute boil test as specified in 407.03.E.2 . Submit all Contractor -furnished de sign mixes to the Department for approval prior to their use. Provide process control of all materials during handling, blending, mixing, and placing operations. If recycled asphalt pavement (RAP) is approved for use as a component material in a hot bitum inous mixture, the Contractor’s Quality Control Plan shall include determination of the gradation and asphalt content of the RAP material at a minimum frequency of 1 stockpile sample per 2,000 tons used in the mixture.
E.Testing Procedures Conduct the Tensile Strength Ratio (TSR), Stripping, and Loss on Ignition (LOI) testing in accordance with the following:
1.Tensile Strength Ratio. Perform testing for stripping and moisture susceptibility of the mixture according to ASTM D 4867 , Standard Test Method for Effect of Moisture on Asphalt -Concrete Paving Mixtures. For all mixtures requiring design, except OGFC, follow ASTM D4867. For OGFC follow ASTM D4867 except as noted:
a.Modify step 8.6.1 so that the three conditioned samples are subjected to a partial vacuum of 26 inches Hg for 10 minutes to whatever degree of saturation achieved.
b.Subject the 3 conditioned samples to one freeze thaw cycle per note 6 listed in ASTM D4867 8.7. except as noted. 407.03 310 c. After 15h in freezer, remove samples and imme diately immerse the still wrapped specimen in 77 °F water for 2 hours.
d.After 2 hours remove specimen from water bath and remove wrapping from specimen then immerse sample in 140 °F water bath for 24 hours. All specimens tested for stripping and moisture su sceptibility shall meet the criteria specified in Table 407.03 -4. Table 407.03 -4: Criteria for Stripping and Moisture Susceptibility Asphalt Cement Minimum Tensile Strength Minimum TSR Polymer Modified 100 psi 80% Non-Polymer Modified 80 psi 80% 411 OGFC 50 psi 80%
2.Ten Minute Boil Test (Stripping )
a.Field Test. Test the completed mix for stripping at the asphalt plant as follows:
1.From a sample of the completed mix, visually select a minimum of 50 grams of the plus No. 4 material and place immediately in boiling water.
2.Continue to boil for 10 minutes, pour off water, and place coated aggregate on a paper towel.
3.Perform a v isual inspection to verify that the coated aggregate shows no evidence of stripping.
b.Laboratory Test. Determine the dosage rate for anti -stripping additive in the laboratory as follows:
1.Wash and surface dry 50 grams of the mineral aggregate passing th e ½-inch sieve and retained on the No. 4 sieve. 407.03 311 2) Thoroughly coat the selected aggregate with the blend by stirring the mixture heated to 250 F.
3.Immediately place the material in boiling water.
4.Continue to boil for 10 minutes, pour off water, and place coated aggregate on a paper towel.
5.Perform a visual inspection to verify that the coated aggregate shows no evidence of stripping.
3.Test for Percent L oss on Ignition (LOI) of the Mineral Aggregate in a n Asphalt Paving Mixture . Conduct Loss on Ignition Testing as follows:
a.Obtain a representative aggregate sample and weigh approxim ately 600 grams into an assayer’ s fire clay crucible that has been ignited to constant weight. Place a cover on t he crucible to prevent pop -out of aggregate while heating.
b.Ignite the covered crucible and its contents in a muffle furnace at 1742 F to constant weight (minimum of 8 hours).
c.Cool the crucible a nd contents to room temperature and weigh . If the aggregate sample is obtained by extraction with a vacuum extractor, correct the weights before and after ignition for filter aid using the following equation: Percent loss on ignition = (A – B) × 100 A Where: A = weight of sample before ignition (corrected for filter aid) B = weight of sample after ignition (corrected for filter aid) 407.04 312 EQUIPMENT
407.04 Bituminous Mixing Plant
Provide sufficient storage space for each size aggregate. Keep the different sizes separated until they have been delivered to the cold elevator or belt feeding the dryer. Maintain the storage yard in a neat and orderly con dition and ensure that the separate stockpiles are readily accessible for sampling. Plants used to prepare bituminous mixture shall meet all requirements specified in 407.04.A. In addition, batch mixing plants shall meet 407.04.B, continuous mixing plants shall meet 407.04.C, and dryer -drum mixing plants shall meet 407.04.D.
A.Requirements for All Plants Mixing plants shall be of sufficient cap acity and so coordinated to adequately handle the proposed bituminous construction.
1.Equipment for Preparing Bituminous Material. Provide tanks that are equipped to heat and hold bituminous material at the required temperatures. The circulating system for the bituminous material shall be designed to ensure proper and continuous circulation during the operating period. Make provisions for measuring and sampling the storage tanks ’ contents .
2.Feeders for Dryer . For each size aggregate, provide s eparate feeders that can deliver the aggregates onto the belt going to the dryer in proper proportions . Use mechanical feeders with separate adjustable gates to feed each size aggregate onto the belt. Provide adequate means to ensure a constant and uniform flow of material from each bin. Equip bins containing fine aggregate with vibrators if necessary. Do not blend or mix different aggregates, or different sizes of the same aggregates, with clam shells, bulldozers, high lifts, or similar equipment. Feed the aggregate into the dryer to obtain a uniform production and uniform temperature. 407.04 313 3. Dryer. The plant shall include a dryer or dryers that are capable of:
a.agitating the aggregate continuously during the heating and drying process ;
b.heating and drying all aggregates to the temperature required ; and
c.supplying the mixing unit continuously at its operating capacity. Ensure that d ryers are constructed and operated so that aggregates will not be contaminated with unburned fuel.
4.Screens. Provide p lant screens, capable of screening all aggregates to the specified sizes and proportions and having normal capacities in excess of the mixer’s full capacity. The Contractor may allow a consistent carry -over, not to exceed 20%, on any screen. If any bin contains more than 20% of material that is undersized for that bin, empty the bin and correct the cause of this condition. Provide approved scalping screens on all dryer -drum mixing plants; additional screens will not be required.
5.Bins. Provide storage bins of sufficient capacity to supply the mixer when it is operating at full capacity. Arrange b ins to ensure separate and adequate storage of appropriate fractions of the mineral aggregates. For each bin, provide overflow pipes of the size and at the location needed to prevent material from backing up into other compartments or bins. Provide e ach compartment with an outlet gate constructed so that , when closed , no leakage occurs. The gates shall be cut off quickly and completely. The bins shall be constructed to provide adequate and convenient approved facilities for obtaining representative samples of aggregate from the full flow of each compartment. These bins are not required in an approved Dryer-Drum Mixing Plant. When using mineral filler , provide separate dry storage and equip the plant to uniformly and accurately feed the filler into the mixer.
6.Bituminous Control Unit and Anti -Stripping Additive (ASA) Systems. Provide means for w eighing or metering the bituminous 407.04 314 material to ensure the proper amount of material i s added to the mix within the tolerance specified. Provide m eans for checking the quantity or rate of flow of bituminous material into the mixer. Where required, use approved in -line blending equipment to add anti-stripping additive, other than hydrated lime, meeting 921.06.B. Provide a storage tank for the ASA that can maintain a constant temperature without overheating the additive. Store the additive according to the manufacturer ’s recommendations and at a temperature of 150 ºF or less. The in-line blending equipment on drum plants shall have a totalizing “flow meter” capable of measuring the actual flow rate within the production range of 0.00 to 1.00 gallons per minute at increments of 0.05 gallons. Batch plants shall have a totalizing flow meter that displays the total gallons of material dispensed. The dispenser and/or pumps shall be capable of adding the heat stable ASA within a tolerance of 10 % of the specified rate.
7.Thermometric Equipment. Fix an armored thermometer, capable of reading an adequate temperature range, in the bituminous feed line at a suitable location near the charging valve at the mixer unit. At the discharge chute of the dryer, also place an approved thermometric instrument that can register automatically or indicate the temperature of the heated aggregates. With the Engineer’s approval, the Contractor may place the thermometric instrument within the fines bin. Equip the plant with an approved automatic recording and regulating apparatus to control the temperature of the aggregates.
8.Dust Collector . Equip the plant with a dust collector constructed to uniformly waste or return to the dried aggregate all or any part of the material collected. Handle collected baghouse fines intended for recirculation into the mix as if it were mineral filler or feed by another suitable method approved by the Engineer. Provide means to calibrate and adjust the dust fed from a baghouse.
9.Safety Requirements . Provide adequate and safe stairways to the mixer platform and sampling points. Place guarded ladders to other plant units at all points requiring access to plant operations. Provide access to the top of truck bodies by a platform or other suitable device to allow the Engineer to obtain samples and mixture 407.04 315 temperature data. Provide a hoist or pulley system to raise scale calibration equipment, sampling equipment, and other similar equipment from the ground to the mixer platform and return. Guard and protect all gears, pulleys, chains, sprockets, and other dangerous moving p arts. Provide ample and unobstructed space on the mixing platform. Maintain a clear and unobstructed passage at all times in and around the truck loading area. Keep this area free of drippings from the mixing platform.
10.Field Laboratory . Provide a Type B field laboratory as specified in 106.06.
11.Surge and Storage Systems . The Contractor may use surge and storage systems if the Department approves each system before use, and if the systems are designed to limit differences between material discharged from the bin or silo and material discharged directly from the plant. Equip the surge bins and storage silos with low and high mix level indicators. Place the low level indicator at a location on the bin or silo that has been predetermined to prevent segregation of the mix. Arrange t he conveyor system used with the surge bins or storage silos so that samples of the mix or dry material may be conveniently taken. Ensure that storage silos are closed, insulated, and heated to prevent localized heating. The storage silo shall be capable of being sealed to prevent oxidation of the m ixture. Equip surge bins with a rain cover capable of preventing water from entering the mix in the bin. The Engineer will base approval of a surge or storage system on inspection and tests that indicate that the system is capable of conveying, retaining, and delivering the bituminous mixture:
a.Within the tolerance ranges as set forth on the JMF;
b.Without segregation; and
c.Without balling or hardening. 407.04 316 The Engineer may withdraw approval of a surge or storage system if tests, inspections, or both indicate that the system is having a detrimental effect on the bituminous mixture. The Engineer will reject bituminous mix found to be damaged in any way by the use of a surge or storage system. Mount, under the loading hopper, platform truck scales that meet the requirements of 109 and that are capable of recording tare and gross weights.
12.Warm Mix Asphalt Process Equipment . The Contractor may modify plants to reduce production and placement temperatures as specified in 407.11.B. Obtain the Department’s approval before making p lant modifications for warm mix asphalt production temperatures . Modifications shall not impair the plant’s ability to maintain temperature control or mixture proportions. Ensure that m odifications made to the plant to reduce mixing temperatures meet the requirements listed for warm mix asphalt additives in the Department’s Qualified Products List ( QPL).
B.Requirements for Batching Plants
1.Plant Scales . Provide dial scales for weighing of all aggregates and mineral filler, in the suspended weigh box. Dial scales shall be of a standard make and of sufficient size to allow the numerals on the dial to be read at a distance of 25 feet. The dials shall be of the compounding type having a full complement of index pointers. The value of the graduation of scales sha ll be as specified in Table 407.04-1. Table 407.0 4-1: Graduation of Scales Aggregate Amount (pounds) Scale Graduation < 5,000 < 5 pounds 5,000 to 10,000 < 10 pounds > 10,000 < 0.1% scale capacity Do not use pointers that give excessive parallax errors. Locate dial scales to be in plain view of the operator at all times. When 407.04 317 bituminous material is measured by weight, equip the asphalt weigh bucket with a separate dial scale with a minimum graduat ion not greater than 2 pounds. All dial scales shall be accurate within a tolerance of 0.5%. Eliminate vibration by setting the scales on a separate foundation, if required. Provide each installation of scales with ten standard 50 -pound weights meeting the requirements of the
U.S. Bureau of Standards for calibrating and testing weighing equipment. Inspect scales as often as the Engineer deems necessary to ensure their continued accuracy. Provide an approved automatic printer system that will print the weights of the material delivered, when the system is used in conjunction with an approved automatic batching and mixing control system. Provide a weigh ticket for each load as evidence of such weights.
2.Weigh Box or Hopper. Provide means for accurately weighing each size of aggregate and mineral filler in a weigh box or hopper suspended on scales. The weigh box or hopper shall be of ample size to hold a full batch without hand raking or running over. The gate shall close tightly so that no material can leak into the mixer while a batch is being weighed.
3.Bituminous Control . Provide a bituminous material bucket of a non-tilting type. The length of the discharge opening or spray bar shall be not less than ¾ the length of the mixer , and it shall di scharge directly into the mixer. T he bituminous material bucket, its discharge v alve or valves, and spray bar shall be adequately heated. Steam jackets, if used, shall be efficiently drainable and all connections shall be so constructed that they will not interfere with the efficient operation of the bituminous scales. The capacity of the bituminous material bucket shall be at least 15% in excess of the weight of bituminous material required in any batch. Provide the plant with an adequately heated, quick -acting, non -drip, charging valve located directly over the bituminous material bucket. If the bituminous material is metered, the indicator dial shall have a capacity of at least 15% in excess of the quantity of bituminous material used in a batch. The meter indicator dial shall have a scale with divisions measuring in gallons equ ivalent to a weight sensitivity of 0.04% of the total batch weight. The meter shall be accurate within a tolerance of 0.5%. The controls shall be capable of being locked at any dial setting and automatically resetting to that reading after the addition o f bituminous material to each batch. The 407.04 318 dial shall be in full view of the mixer operator. Automatically control the flow of bituminous material so that it will begin when the dry-mixing period is over. All of the bituminous material required for one batch shall be discharged in not more than 15 seconds after the flow has started. The size and spacing of the spray bar openings shall provide a uniform application of bituminous material the full length of the mixer. Provide t he section of the bituminous line between the charging valve and the spray bar with a valve, and provide the spray bar with a valve and outlet for checking the meter when a metering device is substituted for a bituminous material bucket.
4.Mixer. Provide an approved twin pugmill type mixer, steam or hot oil jacketed, that is capable of producing a uniform mixture within the job mix tolerances and that is constructed to prevent leakage of its contents. Equip the mixer with a suff icient number of paddles or blades set in the “run around” order, and operate at such speed as to produce a properly and uniformly mixed batch. The depth of the material in the pugmill shall not be above the tips of the paddles. If not enclosed, equip th e mixer box with a dust hood to prevent loss of dust. The clearance of blades from all fixed and moving parts shall not exceed 1 inch unless the maximum diameter of the aggregate in the mix exceeds 1 -1/4 inches, in which case the clearance shall not exceed 1-1/2 inches.
5.Control of Mixing Time . Equip the mixer with an accurate time lock to control the operations of a complete mixing cycle. It shall lock the weigh box gate after the charging of the mixer until the closing of the mi xer gate, at the completion of the cycle. It shall lock the bituminous material bucket throughout the dry -mixing period and shall lock the mixer gate throughout the dry and wet - mixing periods. The dry -mixing period is defined as the time interval between the opening of the weigh box gate and the start of introduction of bituminous material. The wet -mixing period is the time interval between the start of introduction of bituminous material and the opening of the mixer gate. The control of the timing shall be flexible and capable of being set at intervals of 5 seconds or less throughout a total cycle of up to 3 minutes. As a part of the timing device, install a mechanical batch counter that is designed to register only batches that have been mixed for the full time interval. Set the time intervals in the presence of and at the direction of the 407.04 319 Engineer, who will then lock the case covering the timing device until a change is needed in the timing periods.
6.Operator’ s Platform Observation House. Equip the plant with a scale observer’s house, mounted on or near the weigh platform and situated so that the aggregate and asphalt scales, asphalt thermometer, and pyrometer are plainly visible from within the house. Using approved ma terials, soundly construct the house to have at least 45 square feet of floor space and to be air conditioned by a unit of at least 12,000 Btu. The Contractor may install all batch controls in the house. However, do not use the house for storage or purpo ses other than to house the batch controls, plant operator, and Department Inspector . If choosing not to move the plant controls into the house, situate it to provide the scale inspector with a full view of the control panel. If the scale -observer’s house is located on the asphalt plant, provide an adequate secondary means of escape in the event of fire or explosion. The Department will consider the house to be part of the plant and will not directly pay for its construction and maintenance.
C.Requirements f or Continuous Mixing Plants
1.Aggregate Proportioning. Provide the plant with means for accurately proportioning each size of aggregate. The plant shall have a feeder mounted under each compartment bin. Each compartment bin shall have an accurately controlled individual gate to form an orifice for measuring volumetrically the material drawn from each compartment. Equip bins with adequate tell -tale devices to indicate the position of the aggregates in the bins at the low er quarter points. The feeding orifice shall be rectangular with one dimension adjustable by positive mechanical means provided with a lock. Provide indicators for each gate to show the respective gate opening in inches. 407.04 320 Ensure that mineral filler can be fed into the mixer continuously and uniformly in the proportion set out in the JMF, and in a manner satisfactory to the Engineer.
2.Weight Calibration of Aggregate Feed. Equip the plant with an approved revolution counte r that is in satisfactory working condition. Provide means to calibrate gate openings by weighing test samples. Make provisions so that materials fed out of individual orifices may be bypassed to individual test boxes. Equip the plants to handle individ ual test samples weighing not less than 200 pounds. Provide accurate scales to weigh such test samples.
3.Synchronization of Aggregate Feed and Bituminous Material Feed. Provide positive interlocking control between the flow of aggregate from the bins and the flow of bituminous material from the meter or other proportioning device. This control may be achieved using mechanical means or any other positive method satisfactory to the Engineer.
4.Mixer. Provide a continuous mixer of an approved twin pugmill type, which is adequately heated and capable of producing a uniform mixture within the job mix tolerances. The paddles shall be adjustable for angular position on the shafts and reversible to retard the flow of the mix. The mixer shall have a manufacturer’s plate indicating the net volumetric contents of the mixer at the several heights inscribed on a permanent gauge. Provide chart s showing the rate of feed of aggregate per minute for the aggregate being used. Determine the mixing time by the weight method, using the following formula (with weights determined for the job using tests conducted by the Engineer ) where: Mixing time in seconds = Pugmill dead capacity in pounds Pugmill output in pounds per second
5.Surge Hopper. Equip the mixer with a discharge hopper with dump gates that will allow rapid and complete discharge of the mixture and of such size and design that no segregation of the mixture occurs.
6.Platform Truck Scales . Platform truck scales shall meet the requirements of 109. 407.04 321 D. Requirements for Dryer -Drum Mixing Plants
1.Control of Aggregate. Stockpile and handle aggregates to prevent any significant amount of segregation, contamination, or degradation. Construct stockpiles as specified in 903.20. Each aggregate shall have a separate feeder with a positive feed that can be easily and accurately calibrated. Provide a flow indicator and an audible warning device on each separate feeder to ensure a constant and uniform flow of aggregate from each bin onto the belt. Feed mineral filler, if required, into the mixer continuously and uniformly in the proportion set out in the JMF and in a manner approved by the Engineer.
2.Synchronization of Aggregate Feed and Bituminous Material Feed. Provide s atisfactory means to allow a positive interlocking control between cold aggregate feed and asphalt. Base the control setting for the asphalt flow on the dry weight of the aggregate. Provide an acceptable method for proportioning asphalt flow as variations in aggregate flow take place. Provide a metering system to measure the flow of asphalt into the drum , and locate an approved method of checking and calibrating the metering system in the control house. Provide a n automatic interlock system that will shut off the asphalt flow and the burner when the aggregate flow ceases.
3.Temperature Control. Provide dryer -drum mixing plants equipped with a recording pyrometer or other approved thermometric instrument sensitive to a rate of temperat ure change of not less than 10 F per minute. The system shall be equipped with automatic burner controls and shall provide for temperature sensing of the bituminous mixture at discharge from the drum.
4.Scales and Metering Systems. Provide weights and charts for checking the accuracy of the belt scales and the bituminous metering system. The scales and meters shall be accurate within a tolerance of 0.5%. The belt scale that weighs the combined aggregate shall be in accordance with the National Institute of Standards and Technology Handbook 44. 407.04 322 5. Sampling Devices . Use an approved method for sampling individual cold feeds and sequential sampling of aggregate and asphalt under full scale production. The sampling device and procedures used shall be approved by the Engineer and shall not interrupt normal operation.
6.Platform Scales. Make certified platform scales available for checking the asphalt metering system and for weighing or checking loads of asphalt mix as specified in 109.
7.Silos or Surge Bins . Provide surge bins or storage silos as specified in 407.04.A.11 . If a silo is not provided, use an approved surge bin capable of holding sufficient mix to allow the plant to operate at an efficient rate of production, and ensure the system is capable of conveying, retaining , and delivering the bituminous mixture so that it is within the JMF and without segregation . The Engineer will reject mix that is damaged in any way. The surge bin may include an approved weighing sys tem. If a weighing system is included in the surge system, provide approved weights for checking the weighing system. Check the system in maximum increments of 5,000 pounds and in a minimum of 3 increments. Check the system through its entire weighing r ange to or above the maximum weight that is expected to be applied. The system shall be accurate within a tolerance of 0.5%. For surge bins that do not include a weighing system, mount platform truck scales meeting the requirements of 109 under the loading hopper.
8.Aggregate Feed. Proportion aggregate by feeding each size aggregate from a separate cold bin. The belt that delivers the aggregate shall have a load cell capable of registering the amount of flow from each individ ual bin on a readout in the control office; alternatively, the Contractor may proportion the aggregate by a linear system based on measured RPM of each feeder belt at a constant gate opening to feed aggregate at a predetermined rate that is set in the cont rol office and that has a readout in the control office. Ensure that the rate of feed as determined from the bin settings agrees with the load cell on the collection belt feeding the dryer within a tolerance of plus or minus 10%. If the predetermined tolerance is exceeded, an alarm shall sound, and if corrections are not made within 60 seconds, the plant shall automatically shut down. 407.05 323 The aggregate feed system shall employ computer controlled adjustments to automatically produce mix of the correct propor tions over the plant’s entire range of production rates. If the Engineer has previously calibrated and approved the plant for temporary manual operation, the plant may run for a period not to exceed 2 working days, or portions thereof, on manual should a computer breakdown occur.
9.Electronic Data Retention. The computer system and automatic weighing system shall include means to retain all electronic data during electrical power failures.
407.05 Hauling Equipment
Trucks used for hauling bituminous mixtures shall have tight, clean, smooth metal beds that have been thinly coated with a minimum amount of paraffin oil, hydrated -lime solution, or other approved material from the Department’s QPL to prevent the mixture f rom adhering to the beds. Immediately after loading at the plant, cover each truck with a cover of canvas or other suitable material that is of sufficient size to protect the mixture from the weather. Allow the cover to lap down along the sides and rear of the truck bed a minimum of 6 inches, and use tie downs to secure the cover at a maximum of 5-foot spacing along the sides and rear of the truck bed. When necessary to ensure the mixture will be delivered on the road at the specified temperature, insula te truck beds and securely fasten the covers. Provide a 3/8-inch hole in both sides of each truck bed for inserting a thermometer.
407.06 Bituminous Pavers and Material Transfer Devices
A.Pavers Bituminous pavers shall be self -contained, power -propelled units provided with an activated screed, equipped to be heated, and capable of spreading and finishing courses of bituminous pl ant mix material in lane widths applicable to the specified typical section and thickness shown on the Plans. All screed extensions shall be full assembly extensions, including activated and heated screeds. Pavers shall include throw -back blades, reverse augers, or equivalent to place mix beneath the auger gearbox. Auger extensions shall be incorporated in a manner such that the maximum distance from the augers to the end plate shall be 18 inches. Screed extensions may extend beyond the 18 -inch maximum from auger extensions only when extending for short -term temporary deviations in 407.06 324 pavement width such as driveways. Do not use strike -off boxes, with the exception of sections with continuously varying width. Equip the paver with a receiving hopper that ha s sufficient capacity for a uniform spreading operation. The hopper shall be equipped with a distribution system to place the mixture uniformly in front of the screed. The screed or strike -off assembly shall produce a finished surface of the required even ness and texture without tearing, shoving, or gouging the mixture. Equip all asphalt paving machines with automatic grade and slope controls. Both the grade and slope controls shall be in working order at all times; however, if the automatic controls fail, the Contractor may finish the day’s work using manual controls, but shall not resume work the following day until both the grade and slope controls are in first class working order. The Engineer may allow the Contractor to pave the inside shoulder concurrently with the inside traffic lane, subject to the Engineer’s approval of the price adjustment for the mix used on the shoulder and of the paving and rolling equipment. In addition, the paver shall have an articulated scree d that can be adjusted to fit the pavement cross -section and a power unit capable of handling the increased loading without undue stress.
B.Material Transfer Devices (MTDs) Provide a Material Transfer Device (MTD) capable of transferring the asphalt from the truck or trailer to the asphalt paver without coming in contact with the asphalt paver. Use a MTD when placing all asphalt mixes, including shoulder mixes, with the exception that it will not be required when placing CS mix. An exception may be allowed due to lane width or safety issues if approved by the Engineer. The MTD shall have a minimum storage capacity of 15 tons, and shall be equipped with mixing augers in the bottom of the storage hopper that are capable of remixing or re -blending the material as the material is removed from the storage hopper. The mixing augers shall be operational and used at all times during placement of the asphalt mixes. The MTD shall have a rear discharge conveyor that swivels a minimum of 150 degrees to allow feeding th e paving machine from the front, side or rear. 407.07 325 Insert a stationary surge hopper into the paving hopper of the paver being fed by the MTD. The stationary surge hopper shall be considered as part of the MTD and shall have sloping sides (minimum of 60 degrees from horizontal) and a minimum storage capacity of 15 tons. Obtain the Department’s approval of models and manufacturers of MTDs before using on the Project. The Department will make no direct payment for use of an MTD and will consider all cost of furn ishing and operating the MTD as incidental to the work.
407.07 Rollers
Provide self -propelled rollers, of steel -wheel, pneumatic tire, and/or vibratory type, which are in good condition and capable of reversi ng without backlash. Operate rollers at speeds slow enough to avoid displacement of the bituminous mixture. Equip rollers with a device for moistening and cleaning the wheels as required. The required rollers shall be on the job, inspected, and approved before the start of paving operations. Rollers shall meet the following additional requirements:
1.The steel-wheel roller shall weigh a minimum of 8 tons and may be either a three wheel or tandem type.
2.The pneumatic tire rollers shall have a minimum contact pressure of 85 pounds per square inch . The roller shall contain two axles upon which at least seven pneumatic -tire wheels are mounted to ensure the rear set of tires will not track the front set. Th e axles shall be mounted in a rigid frame provided with a loading platform or body suitable for ballast loading. Uniformly inflate t he tires. Provide the Engineer with charts or tabulations of the contact area and contact pressures for the full range of tire inflation pressures and loadings for each size of roller tire provided. In place of a pneumatic tire roller, the Contractor may substitute a combination roller (pneumatic and steel wheel combination) of the make and model approved by the Department.
3.The Contractor may use vibratory rollers if the Engineer approves the particular roller proposed for use. 407.08 326 When paving the inside shoulder concurrently with the insid e traffic lane, provide an additional roller, having a minimum width of 4 feet to a maximum width of 1 foot wider than the inside shoulder being paved, to compact the shoulder. Do not allow either the roller(s) on the inside traffic lane or the roller on the shoulder to traverse between the inside shoulder and the inside traffic lane.
407.08 Small Tools
Provide all necessary small tools, and keep them clean and free from accumulations of bituminous materials. CONSTRUCTION REQUIREMENTS
407.09 Weather Limi tations
The Contractor may place bituminous plant mix on properly constructed and accepted subgrade or previously applied layers if:
1.The subgrade and the surface upon which the bituminous plant mix is to be placed is free of excessive moisture , and
2.The bituminous plant mix is placed according to the temperature limitations specified in Table 407.09 -1 and when weather conditions otherwise allow the pavement to be properly placed, compacted , and finished. Table 407.09-1: Temperature Limitations Compacted Thickness Minimum Air or Surface Temperature (°F) Unmodified mixes (PG 64, 67) Modified mixes (PG 70, 76, 82) < 1.5 inches 45 55 > 1.5 inches to < 3.0 inches 40 50 ≥ 3.0 inches 35 45
3.Do not place bituminous plant mix, with a compacted thickness of 1.5 inches or less, between November 30 and April 1. Do not place 407.09 327 bituminous plant mix, with a compacted thickness greater than 1.5 inches, between December 15 and March 16. Only place 411-TL, 411-TLD, 411-TLE, and 411-OGFC mixtures when the pavement surface temperature and the ambient air temperature are a minimum of 55 F and rising ; limit placement to the period from April 1 to November 1. If the temperature meets the above requirements, outside of normal paving season, a request for a seasonal limitation waiver may be submitted for Departmental consideration. Requests shall be submitted in writing at least one week before the anticipated need.
4.If determined necessary by the Departmen t, the Contractor may request a variance from the above required temperature s and seasonal limitations to pave at lower temperatures by submitting a Cold Weather Paving and Compaction Plan. All projects requiring a Cold Weather Paving and Compaction Plan shall utilize Intelligent Compaction to demonstrate proper coverage and compaction temperature at no additional cost to the Department; with the exception of small quantity projects, such as, but not limited to, bridge approaches, intersections, and tempor ary traffic shifts. Upon completion, the documentation showing appropriate coverage and compaction temperature shall be provided to the Department. Submit requests in writing at least one week before the anticipated need, and include a Cold Weather Pavin g and Compaction Plan that meets the De partment’s Procedure. The plan shall identify what practices and precautions the Contractor intends to use to ensure the mixture is placed and compacted to meet the specifications. The plan shall include compaction cooling curves estimating the time available for compaction, the intended production, haul, and compaction rates , with paver and roller speeds estimated. The Contractor may consider using such p ractices as the addition of rollers, reduced production and paving rates, insulated truck beds, and heating the existing surface. In no cases will a Cold Weather Paving and Compaction Plan or seasonal lim itation waiver be approved for 411 -OGFC, 411 -TL, 411-TLD, or 411-TLE. If the specified densities are not obta ined, stop all paving operations and develop a new plan. All mixture failing to meet specifications will be subject to price adjustments or removal and replacement at no cost to the Department . 407.10 328 407.10 Conditioning the Existing Surface If bituminous mixes are to be placed upon an existing concrete pavement, with or without a bituminous overlay, remove all excess bituminous material from joints and cracks. Remove sections of existing pavement that are broken and pumping under traffic. Remove pavement where bl owups have occurred at joints or cracks to provide a minimum opening of 1 foot for the full width of the pavement. If the bituminous mixture is to be placed upon an existing bituminous pavement, remove areas containing excess bitumen and failures in the existing surface and base as directed by the Engineer. Adjust all manholes and catch basin frames, which are associated with the storm sewer system, to the finished grades of the pavement. Unless otherwise specified, make such adjustments at no additional c ost to the Department. The respective Utility Owner(s) will properly adjust all utility manholes, utility valve covers, and similar structures, to the finished grades of the pavement, unless otherwise shown on the Plans. Remove unsatisfactory subgrade mat erial encountered when removing the existing pavement and replace with approved material. Use overlay mixture or other approved material to fill openings left by the pavement and base removal to the full depth of the existing pavement, as directed by the Engineer, and compact the material in layers not to exceed 3 inches in thickness. Paint contact surfaces of curbing, gutters, manholes, and other structures with a thin, uniform coating of bituminous material before placing the mixture against them. When shown on the Plans, bring existing surfaces that are warped and irregular to uniform grade and cross -section using the leveling mixture specified in 307.
407.11 Preparing the Bituminous Material
A.Hot Mix Asphalt (HMA) Heat the bituminous materials for hot mixes to the required mixing temperature specified in Table 407.11 -1. 407.11 329 Table 407.11-1: Mixing Temperatures PG Binder Grade Minimum Temperature ( °F) Maximum Temperature ( °F) PG 64-22, PG 67 -22 270 310 PG 70-22 290 330 PG 76-22 290 330 PG82-22 290 330 Minimum temperature for OGFC mixes shall be 280º. The temperature for Grading AS, Grading ACRL , and Grading TPB mixtures shall be between 225 and 275 °F, except when modified binders are used, and then the temperatures shall be between 250 and 310 °F. Aggregate should be coated, and no visible drain down should occur in storage silos or hauling equ ipment.
B.Warm Mix Asphalt (WMA) The Contractor may subject the produced mixture to reduced production and placement temperatures by adding a chemical warm mix additive meeting 921.06.B.3 or by making plant modifications as specified in
407.04 A.12.
When using either WMA technology, the maximum mixing temperature for any grade of asphalt cement shall be no more than 300 °F. At the beginning of a day’s production, the producer may produce up to five truckloads at the temperatures specified in Table 407.11-1 to pre-heat placement equipment (pavers, transfer devices) before producing WMA. Indicate the laboratory mixing and compaction temperatures on the JMF during the mix design approval process. A tolerance of plus or minus 5.0 °F for each temperature will be allowed. During test str ip construction, ensure that all plant-produced WMA exhibits the ability to meet the test requirements for tensile strength ratio (TSR), conditioned tensile strength, Marshall Stability and flow, volumetrics, and boil test , as specified for HMA in specifications 307, 407, and 411. Procedures for testing shall be in accordance with that which is defined for quality control and accep tance in 407.03.D.2.h and
407.20 B.3 , respectively.
407.12 330 407.12 Preparation of Aggregates Unless otherwise specified, dry and heat the aggregate for hot mi xes to produce a completed mix of a uniform temperature as specified in Table
407.11 1. Adjust flames used for drying and heating to avoid damage to the
aggregate and to avoid soot on the aggregate. On all plants requiring screens, screen the hot dried ag gregate into two or more fractions as specified. Convey the separated fractions into separate compartments ready for batching and mixing with bituminous material.
407.13 Mixing
Combine the dried aggregates within the mixer in the amount of each fraction of aggregates required to meet the JMF. Measure the bituminous material and introduce it into the mixer in the amount specified by the JMF. After introducing the required amounts of aggregate and bituminous material into the mixer, mix the materials as long as necessary to obtain a complete and uniform coating of the particles and a thorough distribution of the bituminous material. The Engineer will determine wet -mixing time for each plant and for each type of aggregate used, but in no case shall the wet -mixing time be less than 25 seconds for batch type plants and 40 seconds for continuous mix plants. The temperature of the completed mixture (determined at the time it is dumped from the mixer), made with aggregates containing absorbed moisture that causes foaming or boiling in the completed mix, shall be not less than 225 °F. The temperature of the mix when it is discharged from the mixer shall not deviate from that specified in 407.11.A. The Contractor may place h ot-mixed bituminous mixtures in surge or storage silos if the mixture as used from the silos meets all the specification requirements for the particular mix involved. When using surge or storage silos , as approved by the Engineer, meet the following additional requirements:
1.Provide a surge bin or storage silo system meeting 407.04.A.11 .
2.Empty the storage silos or surge bins when directed by the Engineer to check material quantities. 407.14 331 3. Limit hours of plant operation, whether for storage or direct shipment to the road, to reasonable working hou rs to allow normal inspection of plant operations.
4.Remove b ituminous mixtures placed in a surge bin on the same day in which it is stored.
5.The Contractor may store b ituminous mixtures of Gradings A, AS, ACRL, and B for up to 48 hours, and Gradings BM, BM2, C, CS, CW, D, E , and F for up to 96 hours , in a storage silo by complying with the following:
a.Add an approved silicone additive to the asphalt cement for mixes to be stored beyond the day of mixing.
b.Keep the stored bituminous mixture sealed at all times during storage.
c.Fill the storage silo to at least 90% of capacity.
6.The Inspector will take s amples of the stored material following the period of storage.
7.The stored m aterial is subject to th e same temperature, segregation, and laying requirements as required for unstored plant production.
8.The Engineer will reject mixtures having e xcessive segregation, lumpiness, or stiffness.
9.Locate the surge bins and storage silos in a position that en ables the top of the truckload to be visible to the load operator during the loading operation.
407.14 Spreading and Finishing
For Contracts requiring night work, supply sufficient lighting and e quipment as specified in 712.04.H . The temperature of the mixture at the time of depositing in the paver hopper shall be as specified in Table 407.11-1. 407.14 332 Place the mixture upon an approved surface, and spread and strike -off to the established lift thickness, line, grade, and elevation using approved asphalt paving machine(s). The Engineer may approve use of echelon or full -width paving if plant production is capable of supplying the paver s o that a constant forward speed can be maintained. Use preset control string lines to control the alignment of the outside edge of the pavement. Where multi -course pavements are placed, offset the longitudinal joint in one layer from that in preceding la yer by approximately 1 foot; however, construct the joint in the top layer at the centerline of the pavement if the roadway comprises two lane widths, or at lane lines if the roadway is more than two lanes in width. Pave in the direction of traffic. Do not feed a paving machine from more than one asphalt plant. Coordinate plant production and paving operations to ensure constant forward movement of the pavers. The Engineer will consider repetitive interruptions or stopping of the paver as cause for stopp ing the work until the Contractor corrects the situation. If the paver must be stopped for a significant period of time, construct a joint and move the paver from the roadway before the bituminous mixture has cooled sufficiently to prevent proper compacti on. If the bituminous mixture cools to the extent that the required density cannot be obtained, remove and replace the mixture at no cost to the Department. Unevenness of texture, segregation (including end -of-load segregation) or tearing or shoving of bi tuminous mixture during the paving operation, shall be reason to stop the paving . Only resume paving operations when the condition is corrected . Immediately remove u nacceptable mix and replace at no cost to the Department . The Department will not allow excessive throwing back of the bituminous mixture. Any amount of mixture not fully adhered to the roadway shall be repaired prior to completion of the project. If the failure is not repaired the same day as originally placed, the method of repair must be approved by the Engineer prior to beginning of the repair. The repairs will be no additional cost to the Department. Provide a utomatic screed controls using either the string line, ski type grade reference system , or a non -contact averaging system on all work regardless of the paver width . The Engineer may require a string line reference system on new construction. If the base has been finished with equipment having automatic grade control or the Contractor demon strates that an alternate method of spreading and finishing will result in a satisfactory riding surface, the Engineer may conditionally waive the string line requirement and authorize use of the ski type reference system. Regardless, the Engineer may at any time require the use of a string line reference system, even if previously waived, if in the Engineer’s opinion, the use of the string line will result in a 407.15 333 superior riding surface. When the string line system is required on a multi - course pavement, u se it on at least two courses exclusive of the surface course. When using the ski type system, the ski shall have the maximum practical length and in no case shall it be less than 40 feet in length. Pavement lanes previously placed with automatic control s or to form grade may serve as the longitudinal control reference for placing adjacent lanes by using a ski or joint matching shoe. The string line reference system shall consist of suitable wire or twine supported by approved devices that are compatible with the type of automatic paver control system used. The string line and supports shall be capable of maintaining the line and grade shown on the Plans at the point of support while withstanding the tensioning necessary to prevent sag in excess of ¼ inches between supports spaced 50 feet apart. Install additional supports to provide a minimum spacing of 25 feet, or less as directed by the Engineer, to remove the apparent deviation of the string line from theoretical grade. Provide all materials, equipmen t, labor, and incidentals necessary to construct the string line reference system, and maintain the system until its use is no longer required. Include the cost of erecting and maintaining the string line reference system in the unit price bid for other i tems of construction. Have the string line reference system be complete in place at least 300 feet in advance of the point where the pavement is being placed . Automatic screed controls are not required on sections of projects where service connections and other conditions interfere with their efficient operation. On areas where irregularities or unavoidable obstacles make the use of mechanical spreading and finishing equipment impracticable, take the mixture from the hopper of the spreading machine and di stribute it immediately into place using suitable shovels and other tools, and spread the mixture with rakes and lutes in a uniformly loose layer of such depth as will result in a completed course having the required thickness. The Contractor and the Depar tment will each be required to have an individual onsite that is certified by the Department through the HMA Roadway Certification Course.
407.15 Compaction
A.General After spreading and striking -off the bituminous mixture and adjusting surface irregularities, thoroughly compact the mixture using methods 407.15 334 approved by the Engineer and that are capable of achieving the specified density while the material is in a workable condition. When no density requirements are specified, use a system of compaction for roadway pavements that has previously produced the required bituminous pavement densities. The Engineer may require a control strip and random density samples to evaluate the system. In general, accomplish compaction using a combination of the equipment specified in 407.07. As a minimum, meet the roller requirements in Table 407.15 , but increase the number of rollers if the required results are not being obtained. Table 407.15 – Roller Requirements by Mix Type Mix Type Roller Requirements 307-A, 307-B, 307-BM-2, 307-C, 307-CW (except surface) 3 Rollers (Intermediate roller shall be Pneumatic) 307-AS, 307-ACRL, 411 -D, 411-E, 307-CW (surface), 313 -Asphalt Treated Permeable Base 3 Rollers (unspecified) 411-TL, 411-TLD, 411 -TLE, 307 -CS (when paved as a continuous layer) 2 Rollers (unspecified) 411-OGFC 2 Rollers (both rollers shall be stati c steel double drum, 10 Ton minimum Any mix used for scratch paving 2 Rollers (breakdown shall be pneumatic)
1.If the compaction effort is detrimental to the quality of the mat, immediately stop and re -evaluate rolling patterns and equipment. To modif y the roller train from that which is specified for the mix, submit to the engineer a written request of the rollers to be substituted and a narrative explanation of how the specified equipment has been detrimental to the quality of the pavement.
2.The Depa rtment will only consider requests for substitution of equipment when it is shown that best practices are being followed and that the problem is not due to improper operation or poor maintenance of the equipment. If this request is approved by the Engineer, a new test strip and roller pattern shall be established.
3.With the Engineer’s approval, the Contractor may reduce the minimum number of rollers listed above to one roller of either the 407.15 335 steel-wheel or vibratory type on the following types of construction and projects:
a.Shoulder construction,
b.Incidental construc tion such as bridge approaches and driveways, and
c.Projects containing less than 1,000 tons of bituminous pavement.
4.Compaction of 411-OGFC mixtures shall consist of a minimum of two passes before the material temperature has fallen below 185 °F. Unless otherwise directed by the Engineer, begin rolling at the low side and proceed longitudinally parallel to the road centerline. When paving i n echelon, or abutting a previously placed lane, roll the longitudinal joint first, followed by the regular rolling procedure. When paving in echelon, rollers shall not compact within 6 inches of an edge where an adjacent lane is to be placed. Operate ro llers at a slow uniform speed with the drive wheels nearer the paver, and keep the rollers as nearly as possible in continuous operation. Continue rolling until all roller marks are eliminated. Do not park rollers on the bituminous pavement. To prevent a dhesion of the mixture to the rollers, keep the wheels properly moistened with water or water mixed with very small quantities of detergent or other approved material. Limit excess use of liquid. Do not refuel rollers on bituminous pavements. Along forms, curbs, headers, walls and other places not accessible to the rollers, compact the mixture thoroughly using hot hand tampers, smoothing irons, or with mechanical tampers. On depressed areas, the Contractor may use a trench roller to compact the mix.
B.Density Requirements Meet the applicable density requirements specified in Table 407.15 -1. 407.15 336 Table 407.15-1: Density Requirements for Bituminous Pavement Mix Type % of Maximum Theoretical Density (Lot Average) No Single Test Less Than, % (Sub Lot) Travel Lanes ADT <1,000 A, B, BM, BM -2, C, CW, D, E 90.0 87.0 Travel Lanes 1,000 <ADT <3,000 A, B, BM, BM -2, C, CW, D, E 91.0 89.0 Travel Lanes ADT >3,000 A, B, BM, BM -2, C, CW, D, E 92.0 90.0 Travel Lanes and Shoulders Any ADT CS, TL, TLD, TLE, OGFC NA NA Shoulders B, BM, BM -2, D, E 88.0 85.0 Correct sublots that test below the minimum density so that the density of the area is equal to or above the minimum , at which point it can be used to determine the average density of the lot. Do not place any successive layer s until the area has been corrected. As necessary to determine the classification of open graded or dense graded mixes and to measure segregation, use AASHTO T 269 or ASTM D3203. Repair or replace defective mixture to the satisfaction of the Engineer and at no cost to the Department . The Department will perform density testing in accordance with
407.20 B.5 .
C.Test Strips Construct tes t strips for all A, B, BM, BM-2, C, CW, D, and E mixes to establish rolling patterns, to accommodate the Department to calibrate nuclear gauges, to verify that the base course or surface course mixture meets the density requirements of the specifications, and for mix design 407.15 337 and production verification as required. A test strip is not required for mixes AS, A-CRL, CS, TL, TLD, and TLE, but adjustments to the roller pattern may be made at the direction of the Engineer. Before constructing the test strip, obt ain the Engineer’s approval of t he underlying base or other pavement course. Compact the test strip using equipment as specified in this subsection and 407.07. Construct t he test strip at the beginning of work on the pavement course. Prepare n ew test strips when:
1.A change in the JMF is necessary ;
2.A change in the source of materials occurs ;
3.A change in the material from the same source is observed;
4.There is reason to believe that the test strip density is not representative of the bituminous mixture being placed; and when
5.A change in paving or compaction equipment occurs. With the approval of the Engineer, the Contractor may construct additional test strip s. Construct each test strip with approved bituminous mixture. The test strip shall remain in place as a section of the completed work. Construct each test strip to be 1 paver width wide, with an area of at least 400 square yards and of the depth specifi ed for the pavement course concerned. Immediately after placing the bituminous mixture , begin compacting the test strip. Perform compaction in a continuous and uniform manner over the entire test strip. Continue compacting the test strip until additional roller coverage will produce no appreciable increase in density (1 pound per cubic foot), as measured using a nuclear gauge. Use the roller coverage necessary to obtain this maximum density as the rolling pattern for the remainder of the project. Take cores on the test strip at ten locations as designated by the Engineer . Provide these cores to the Department for use in calibrating the nuclear 407.16 338 gauge and to verify that the average density of the test strip meets the density requirements of the specificat ions. The Department will report all densities using the corrected nuclear gauge readings. Correction factors are specific to the project, mix design and the nuclear gauges used during the test strip construction. If a different mix design or nuclear gauge needs to be used, it will be necessary to cut new cores from the ongoing pavement construction to establish a new nuclear gauge correction factor . Nuclear gauge correction factors determined for a mix design on another project shall not be used. When testing test strip cores, the Department will determine density (bulk specific gravity) in accordance with AASHTO T 166, Method A only. All core samples shall be completely dry before testing. Air drying is permitted provided core samples are weighed at 2 -hour intervals until dry in accordance with AASHTO T166, Section 6.1. Cores may also be dried in accordance with ASTM D7227. If the density of the asphaltic concrete in the test strip does not meet specification requirements, make whatever ch anges are necessary to obtain the specified density. Use other sources and combinations of aggregates as necessary , subject to the Engineer’s approval, to produce a mix meeting the required density.
407.16 Joints
Place bituminous paving as continuous ly as possible. Do not pass r ollers over the unprotected end of a freshly laid mixture unless approved by the Engineer. Form transverse joints by cutting back on the previous run to expose the full depth of the course. Use a brush or sprayed coat of bituminous material on contact surfaces of longitudinal and transverse joints just before placing additional mixture against the previously rolled material.
407.17 Pavement Samples
When directed, cut sam ples from the compacted pavement for testing by the Engineer. Take samples of the mixture for the full depth of the course at locations selected by the Engineer. Cut the samples with a power saw or core drill. Samples shall have a top surface area of at least 10 inches. Fill holes left by taking samples with the same type mixture that was used to construct the course sampled, and compact to conform to the surrounding pavement. Cut samples and repair sample holes at no cost to the Department. 407.18 339 407.18 Surface Requirements Test the surface with a 12 -foot straightedge applied parallel to the centerline of the pavement. The deviation of the surface from the testing edge of the straightedge shall not exceed that specified for the respective types of bituminous construction und er the applicable Subsections of these Specifications. Test the transverse slopes of tilted pavements with a string -line and string - level applied at right angles to the centerline of the pavement. The percent of slope, when computed for the full width of the pavement, shall not deviate more than 0.5 percentage points from that shown on the Plans. Test the crown in crowned pavements with a string -line applied at right angles to the centerline of the pavement. The crown shall not deviate more than ½ inch from that shown on the Plans. Correct deviations that exceed the specified tolerances. Remove and replace pavement that cannot be corrected to comply with the specified tolerances at no cost to the Department. COMPENSATION
407.19 Method of Measurement
The Department will measure:
1.Asphalt cement and mineral aggregate, including mineral filler when required, by the ton and as follows:
a.If the mix is loaded from a storage or surge bin, the Department will determine quantities by weighing the completed mix on truck scales meeting 109 and calculating the weight of asphalt cement and mineral aggregate based on the percentages measured into the mix by the appropriate scales or meters as specified in 407.04.
b.If the mix is loaded directly into the hauling equipment from a batch plant, the Department will measure asphalt cement and mineral aggregate in batch quantities by scales or scales and meters as specified in 407.04.B. 407.19 340 c. If a continuous mix plant is used, the Department will measure Bituminous Material for Bituminous Plant Mix Pavement by the ton in accordance with 109. The Department will determine quantities of mineral aggregate, includ ing mineral filler when required, by weighing the bituminous pavement mixture on truck scales meeting 109, and deducting the weight of the bituminous material from the weight of total mixture accepted.
d.If recycled mix is permitted, the Department will measure the completed mix, including new mineral aggregate, planings, asphalt cement, and additive, by the ton in accordance with 109.
2.Removal and disposal of existing surf ace (concrete) by the square yards in accordance with 109, if such work is required as specified in 407.10. Such measurement will include the removal of bituminous overlay.
3.Removal and Disposal of Existing Surface (Bituminous) by the square yards in accordance with 109. Such measurement shall include the removal of base material, except concrete, as directed by the Engineer.
4.Removal of unsatisfactory subgrade material where existing pavement has been removed by the cubic yard, in accordance with
203.09 The Department will measure material used to replace such
undercutting in accordance with the spe cification for the type of material used.
5.Adjustment of catch basin grates and frames, water valve boxes, gas valve boxes and manhole covers and frames by each when required.
6.Liquid anti -strip additive by the gallon.
7.Hydrated lime by the ton. The Department will measure bituminous mixtures used to fill openings left by pavement removal as specified in this Subsection 407.19. The Department will measure base materials used to fill openings left by base removal as provided for in the respective Sections for each type specified. The Department will not measure chemical additives or modifiers, when required, for payment, but will consider them incidental to asphalt cement. 407.20 341 The Department will not measure mineral filler separa tely for payment, but will consider it incidental to mineral aggregates.
407.20 Basis of Payment
A.General The Department will pay for accepted quantities of Asphaltic Concrete (Hot Mix) with or without recycled material, at the contract prices, complete in place, as follows: Item Pay Unit Bituminous Plant Mix Base (Hot Mix) Ton The Department will pay for liquid anti -strip additive and hydrated lime anti-strip additive based on certified documentation of material costs not to exceed $15 per gallon and $90 p er ton, respectively. The Department will pay for accepted quantities of Prime Coat or Tack Coat as specified in 402 or 403, respectively. The Department will pay for the work required to prepar e the subgrade, sub-base, base, or surface in accordance with 307.06 and 411.06 as provided for in the applicable Section or Subsection under which the work is performed. The Department will not make direct payment for polymer or other asphalt modifiers, but will consider such additives to be included in the price bid for the modified asphalt cement or modified mixture.
B.Acceptance of the Mixture
1.General. The Department will perform all necessary samplin g and testing for acceptance purposes in strict conformance with the Department’s Policies in addition to monitoring and observing the Contractor’s quality control test procedures and results. However, the Engineer will reject for use in the work any load or loads of mixture which, in the Engineer’s opinion, are unacceptable due to excessive segregation, improper coating of aggregates, or excessively high or low temperature. 407.20 342 The Engineer will accept bituminous mixture at the plan t with respect to gradation and asphalt content, on a lot basis. A standard size lot at the asphalt plant will consist of a continuous shift’s production that does not start over at Midnight . The number of sublots in a lot will vary according to Table 407.20 -1. Table 407.20 -1: Sublot Requirements Quantity (tons) Number of Sublots 3001 – 4000 4 tests 2001 – 3000 3 tests 1001 – 2000 2 tests Less than 1000 1 test When the total plan quantity of any mix is less than 1,000 tons, the Department will accept the mix on the basis of visual inspection and Contractor Quality Control certification. If the daily production of any mix is less than 100 tons, no tests will be required for that quantity of mix. The Department may run extraction, gradation analysis, or other tests deemed necessary for acceptance purposes.
2.Defective Materials
a.Acceptance or Rejection. Consider the Engineer’s decision to be final as to the acceptance, rejection, or acceptance at an adjusted payment of the lots. It is the intent of these specifications that each lot of material will meet specification requirements at the time of acceptance testing. The Department will not take chec k samples for acceptance purposes. All acceptance samples will be split, and half of the sample will be retained by the Inspector. If the results of an acceptance test are questioned, the Central Laboratory will test the remaining half of the acceptance s ample. The Department will use the results obtained by the Central Laboratory to evaluate the quality of the lot.
b.Disposition of L ots. Remove and replace, at no cost to the Department, nonconforming lots of materials, products, or complete construction t hat cannot be corrected by reworking. 407.20 343 Alternatively, the Department may accept the nonconforming work at an adjusted payment as s pecified in these Specifications or as directed by the Engineer. When a deficiency is determined, the Department will apply th e applicable payment as specified in these Specifications to the entire lot. When multiple deficiencies occur, the Department will apply the applicable partial payments to the lot of material that is identified by each deficiency. The Department will app ly the payment adjustment for each deficiency separately to not affect any other payment adjustment occurring for the same lot; however, if there are two or more deficiencies in the gradation acceptance tests, the Department will apply only the greater payment adjustment. When an area or linear measurement is used to specify lot size, the Department will determine the equivalent tons of mix placed in each lot by using the average calculated spread from the plant inspector’s daily report for that day’s prod uction.
3.Acceptance. The Engineer will base a cceptance of the mixture on test results o f consecutive random samples taken from each lot. One random sample will be taken from each sublot. The bituminous mixture will be sampled at the plant according to AA SHTO T 168. The percent bitumen content of the mixture will be determined according to AASHTO T 164 or by AASHTO T 308 except as herein revised. The Contractor may use an approved ignition furnace instead of a vacuum extractor for the use in determining a sphalt content and gradation. The method of calibration and test procedures shall comply with AASHTO T 308 Method A and the following. Monthly, per mixture, the Engineer shall determine the correction factor for the ignition oven used for acceptance of th e mixture per AASHTO T 308 and adjust the Asphalt Cement content for acceptance of the mixture accordingly . Keep records of all correction factors for all mixtures. Adjusted payment for asphalt content and gradation will be based on the ignition furnace results as specified in Table 407.20 -2. Use of this alternative equipment shall be at no additional cost to the Department. The percents passing the sieves will be determined in accordance with AASHTO T 30. 407.20 344 Table 407.20 -2: Acceptance Schedule of Payment (Asphalt Plant Mix Characteristics) Characteristics Pay Factor Average Arithmetic Deviation of the Lot Acceptance Test from the JMF 1 Test 2 Tests or more All mixes except 411-OGFC Asphalt Cement Content (1) (Extraction or ignition oven) 1.00 0.00-0.30 0.00-0.25 0.95 0.31-0.35 0.26-0.30 0.90 0.36-0.40 0.31-0.35 0.80 (2) over 0.40 over 0.35 411-OGFC only Asphalt Cement Content (Extraction or ignition oven 1.00 0.00-0.30 0.00-0.25 0.90 0.31-0.35 0.26-0.30 0.80 0.36-0.40 0.31-0.35 0.60(2) over 0.40 over 0.35 Gradation 3/8 inch sieve and larger 1.00 0.00-6.50 0.00-5.70 0.95 6.51-7.08 5.71-6.20 0.90 7.09-7.66 6.21-6.69 0.80 (2) over 7.66 over 6.69 Gradation No. 4 sieve (3) 1.00 0.00-4.62 0.00-4.00 0.95 4.63-5.20 4.01-4.50 0.90 5.21-5.77 4.51-5.00 0.80 (2) over 5.77 over 5.00 Gradation No. 8, 16, 30 , & 50 sieves (3) 1.00 0.00-3.80 0.00-3.30 0.95 3.81-4.46 3.31-3.91 0.90 4.47-5.12 3.92-4.52 0.80 (2) over 5.12 over 4.52 Gradation No. 100 & 200 sieves (3) 1.00 0.00-1.80 0.00-1.60 0.95 1.81-2.00 1.61-1.75 0.90 2.01-2.20 1.76-1.90 0.80 (2) over 2.20 over 1.90
1.Does not apply to 307 Grading A, AS, or ACRL mixes.
2.If approved by the Engineer, the Contractor may accept the indicated partial pay. The Department may require removal and replacement at no cost. The Contractor may remove and replace at no cost to the Department at any time.
3.When there is more than one reduced payment relating to gradation in 1 lot of material, only the greatest reduction in payment will be applied. Reductions applicable for any other reason will be cumulative. 407.20 345 Deduction for both asphalt content and gradation deficiencies will be cumulative. The Department will apply deductions to the total price of the mix (asphalt cement and aggregate combined) under the item for Asphalt Cement Content and Gradation Deduction.
4.Additional Tests. The Engineer may perform any test at any time to determine the effectiveness of the Contractor’s quality control. In addition, the Department will conduct production verification tests parallel to that which is defined for quality control in 407.03.D.2.h .
5.Acceptance for Mix Density on the Roadway. The Department will apply a deduction in payment, not as a penalty but as liquidated damages, for failure to meet the density requirements specified in
407.15 As soon as practicable after the final rolling is completed
on each lot, the Department will perform 5 density tests at locations determined by the Engineer, and will compute an average of all such tests. Deductions for failure to meet densit y requirements will be computed to the nearest 0.1% as a percentage of the total payment otherwise due for each lot. The percent of total payment to be deducted will be 5 times the percent the average in -place density for each lot that fails to meet 407.15. The Department will make deductions in monies due the Contractor for failure to meet the density requirements under the item for Density Deduction. The Department will conduct acceptance testing for density in accordance wit h ASTM D2950 unless otherwise specified. For projects with total project tonnage per mix type less than 2,000 tons (not including small quantity jobs as defined in 407.20.B.1 ) the Department may alternatively calculate in place density by cores (AASHTO T -166), in this case no cores will be taken for gauge correlation on the test strip. The Department inspector conducting the density tests shall be a certified Nuclear Gauge Field Technician. For density testing purposes, the Department will divide the pavement into lots of 1,000 tons. Five density tests will be performed in each lot and the average results compared with the requirements specified in Table 407.15-1. At the beginning of a project or at any time it is deemed advi sable, the Department may consider smaller lots to evaluate compaction methods or for other reasons as approved or directed by the Engineer. The Department will randomly select acceptance test samples that are representative of the lot or sublot. Although performing compaction after the acceptance test is acceptable, the Department 407.20 346 will use the original test result to determine lot density. The Department may take information only samples to spot check compaction, but will not use these tests for acceptance testing.
C.Adjustments
1.Asphalt Cement Adjustment. If the Engineer sets an asphalt content other than that specified in Tables 307.09-1 and 411.09-1, the Department will calculate a price adjustment, based on the asphalt content set by the Engineer and the Monthly Bituminous Index for the specific grade asphalt on the mix design, according to the following formula: PA = MBI × (DA – BA) × T Where: PA = Price Adjustment MBI = Monthly Bitum inous Index DA = Percent asphalt set on the mix design BA = Percent asphalt specified above to be used for bidding T = Total tons asphalt mix for price adjustment
2.Specific Gravity. In cases where the effective combined specific gravity of the mineral agg regate exceeds 2.80, the Department will adjust the tonnage of mineral aggregate, or plant produced mixture, for payment by multiplying the tonnage of mineral aggregate, or plant produced mixture, used by a specific gravity of 2.80 and dividing by the high er specific gravity.
3.Loss on Ignition (LOI). If the approved JMF includes a surface mixture of limestone with gravel, granite, slag, quartzite or gneiss, perform tests for the percent LOI of the limestone aggregate in the asphalt paving mix as specified in 407.03.E.3 . If the percent of LOI in the aggregate differs by plus or minus 2% from the LOI indicated in the JMF, the Department will make a payment deductio n in the price bid for the mix, not as a penalty but as liquidated damages. The percent of total payment to be deducted will be 5 times the percent that the LOI exceeds the JMF tolerance of plus or minus 2%. 407.20 347 Replace or overlay all mix produced with aggregate tested and found to have a LOI that dif fers plus or minus 6% from the LOI indicated in the JMF at no additional cost to the Department. To determine the deduction, the Department will use lots of approximately 5,000 square yards. The Department inspector will perform sampling and testing to establish th e LOI according to the Department’s sampling and testing procedures. If the initial tests indicate a variation in the LOI of plus or minus 2% than the value shown on the mix design, the Contractor shall perform the additional sampling necessary to establi sh the LOI of the aggregate in each lot, with the cost of the sampling being included in the contract unit prices bid for the paving items. The Department will make deductions for excess variation in LOI under the item for Material Variation (Deduction). 410.01 348 SECTION 410 – BITUMINOUS PLANT MIX SURFACE COURSE (COLD MIX)
410.01 Description ................................ ................................ ................... 348
410.02 Materials ................................ ................................ ...................... 348
410.03 Composition of Mixtures ................................ ............................. 349
410.04 Equipment ................................ ................................ .................... 349
410.05 Limitations ................................ ................................ ................... 349
410.06 Preparing Designated Surface ................................ ...................... 349
410.07 Mixing ................................ ................................ .......................... 350
410.08 Spreading and Finishing ................................ ............................... 350
410.09 Compaction ................................ ................................ .................. 350
410.10 Surface Requirements ................................ ................................ .. 350
410.11 Maintenance ................................ ................................ ................. 350
410.12 Method of Measurement ................................ .............................. 350
410.13 Basis of Payment ................................ ................................ .......... 350
DESCRIPTION
410.01 Description
This work consists of constructing a Bituminous Plant -Mix Surface Course (Cold Mix), composed of aggregate and bituminous material, on a designated base in one or more layers and at the rate of application shown on the Plans or established by the Engineer. MATERIALS
410.02 Materials
Provide materials as specified in: Mineral Aggregate ................................ ................................ . 903.10 Emulsified Asphalt, Grade AE -3 ................................ ........... 904.03
Source: Tennessee Standard Specifications for Road and Bridge Construction, 2021 Edition. Pages 305–356 of 1,072.