SPECIAL SPECIFICATION 3241 Superpave Hot Mix Asphalt Concrete Pavement (SPHMACP)

Transcription

1 1993 Specifications SPECIAL SPECIFICATION 3241 Superpave Hot Mix Asphalt Concrete Pavement (SPHMACP) 1. Description. This Item shall govern the construction of a pavement consisting of a base course, a level-up course, a surface course, or any combination of these courses as shown on the plans. Each course must be composed of a compacted mixture of aggregate and asphalt binder mixed hot in a mixing plant, in accordance with the details shown on the plans and the requirements herein. The following minimum and maximum compacted lift thickness criteria shall apply to all courses of SPHMACP: Mix Type Min (Inches) Max (Inches) 1 1/2 inch inch /4 inch /2 inch (1) Quality Control. Contractor sampling, testing and inspection for operational control. (2) Quality Assurance. Engineer sampling, testing and inspection activities to determine payment and to make acceptance decisions. (3) Verification Tests. Tests to verify accuracy of quality control, quality assurance and mixture design testing. (4) Referee Tests. Tests used to resolve differences between Contractor and Engineer test results. The Construction Division of TxDOT is designated as the referee laboratory. (5) Validation Tests. An independent evaluation to validate test results obtained by the Contractor or Engineer. These tests are performed by a laboratory designated by the Engineer. The test results are not used for acceptance. 2. Certification, Reporting and Quality Control Plan Requirements. (1) Certification. All sampling and testing (Contractor and Engineer) will be conducted by personnel certified by the TxDOT approved program. The certification level required for performance of each test shall comply with requirements shown in Table 7. In addition to the certification requirements in Table 7, all Level II personnel will be required to complete a TxDOT approved Superpave training course. The Contractor shall provide a list of certified personnel to be used on the project prior to the beginning of production. An updated list shall be provided when personnel changes are made. The Contractor's certified Level IA HMA specialist shall be at the plant prior to the beginning of and during plant production operations

2 (2) Reporting. TxDOT's automated hot mix program will be used by the Engineer and the Contractor to record all test data and calculate all pay factors. A diskette copy of the automated hot mix program, provided by the Engineer, shall be used by the Contractor to submit test results to the Engineer. The Contractor and Engineer will exchange test results for each production lot on a daily basis. All pay adjustment factors for the lot will be provided within two (2) working days of receiving the trimmed cores from the Contractor. The Contractor, in accordance with Test Method Tex-233-F shall plot the results of all quality control and quality assurance testing. The control chart shall be updated as soon as test results for each sublot become available and shall be easily and readily accessible at the field laboratory. Failure to maintain control chart updates on a daily basis shall be cause for ceasing production. Production may be resumed once the control charts have been brought current. (3) Quality Control Plan. The Contractor shall designate in writing specific individuals who are responsible for quality control and who have authority to take corrective measures. The QC Plan shall be submitted in writing to the Engineer and must be approved prior to beginning plant production. The QC Plan shall include, but not be limited to, the following operational areas: (a) Material Delivery. - Sequencing of material delivery and minimum quantities of materials to assure continuous plant operations. - Stockpiling procedures to avoid contamination and segregation - Frequency, type and timing of aggregate testing to assure conformance of material requirements prior to mixture production. - Procedure for monitoring the quality and variability of asphalt binder material. (b) Production. - Loader operation procedures to avoid contamination in cold bins. - Procedure for control of cold feeds for consistent feeding, adjustments for material gradation changes and calibrations. - Scalping screens size and location. - Procedures for controlling and verifying rates of mix additives. - Reporting procedures for job control test results. - Procedures to avoid segregation in the silo. - Procedure to avoid segregation in the loading of trucks

3 (c) Placement and Compaction. - Requirements for pre-paving meeting and agenda. - Procedures for transfer of mixture into paver to avoid segregation and material spillage. - Paver operations to avoid segregation and surface irregularities such as operation of wings, height of mix in auger chamber, etc. - Procedure to achieve continuous paver operation. - Procedure to achieve quality longitudinal and transverse joints. - Procedure to minimize thermal and physical (aggregate) segregation. - Procedure establishing compactive effort to achieve mat density. This quality program shall specifically address actions the Contractor will implement in each of the above areas and shall be approved by the Contractor's management official who supervises the specifically named individuals. Contractor operations shall follow the approved quality control plan in detail. Changes to the quality control plan may be made during the project if approved in advance by the Engineer. All approved changes must be in writing. When any point of non-compliance with the quality control plan comes to the attention of either the Contractor or the Engineer, the other party shall be notified immediately and the Contractor shall take appropriate corrective actions. Failure to take corrective actions within 24 hours shall be cause for operations to cease as determined by the Engineer. 3. Materials. The Contractor shall furnish materials to the project meeting the following requirements prior to mixing. Additional test requirements affecting the quality of individual materials or the paving mixture shall be required when indicated on the plans. (1) Aggregate. The aggregate shall be composed of a coarse aggregate, a fine aggregate, and if required or allowed, mineral filler, and may include reclaimed asphalt pavement (RAP). Aggregate stockpiles proposed for use will be sampled and tested by the Engineer for approval in accordance with Item 6, "Control of Materials". Aggregate from each source, shall meet the quality requirements of Table 1 and other requirements as specified herein. The aggregate contained in RAP will not be required to meet Table 1 requirements. (a) Coarse Aggregate. Coarse aggregate is defined as that part of the aggregate retained on a No. 8 sieve and shall be natural material, unless otherwise approved by the Engineer, and shall be of uniform quality throughout. Coarse aggregate stockpiles shall contain no more than 20 percent by weight of material passing the No. 8 sieve. When specified on the plans, certain coarse aggregate material may be allowed, required or prohibited

4 Gravel from each source, including the gravel aggregate from RAP, shall be so crushed as to have a minimum of 90 percent of the particles retained on the No. 4 sieve with two (2) or more mechanically induced crushed faces, as determined by Test Method Tex-460-A (Part I). The material passing the No. 4 sieve and retained on the No. 8 sieve must be the product of crushing aggregate that was originally retained on the No. 4 sieve. Coarse aggregates to be used in surface courses shall have a minimum surface aggregate classification as shown on the plans. Unless otherwise shown on the plans, the surface aggregate classification requirement will apply only to aggregate used on travel lanes. The surface aggregate classifications for sources on the Aggregate Quality Monitoring Program (AQMP) are listed in the Rated Source Quality Catalog (RSQC). When aggregates are supplied from a source that is not on the AQMP, the aggregate will be sampled and tested prior to use. The procedures will be in accordance with the AQMP. Blending of a Class B aggregate with a Class A aggregate is allowed in order to meet requirements for Class A materials. At least 50 percent (by weight) of the material retained on the No. 4 sieve must come from a Class A aggregate source. The aggregates must be blended by volume if the bulk specific gravity of the Class A and Class B aggregates differ by more than Class C and D aggregate shall not be blended. When RAP is used in the surfacing mix, the coarse aggregate fraction will be considered as a Class B aggregate for purposes of blending calculations. (b) Recycled Asphalt Pavement (RAP). RAP is defined as a salvaged, milled, pulverized, broken or crushed asphalt pavement. The RAP to be used in the mix shall be crushed or broken to the extent that 100 percent will pass the two (2) inch sieve. The Contractor has the option to use up to 15 percent RAP in surfacing mixtures and level-ups and up to 20 percent in RAP in base course mixtures. Only RAP from designated State owned sources may be used in surface mixtures. The stockpiled RAP shall not be contaminated by dirt or other objectionable materials. Unless otherwise shown on the plans, stockpiled, crushed RAP shall have either a decantation of five (5) percent or less or a plasticity index of eight (8) or less, when tested in accordance with Test Method Tex-406-A (Part I), or Test Method Tex-106-E, respectively. This requirement applies to stockpiled RAP from which the asphalt has not been removed by extraction. When shown on the plans or when designated in a special provision, State owned RAP sources are available to the Contractor. The approximate asphalt material content and asphalt cement properties will be shown on the plans. If the source is an existing stockpile material, the decantation or plasticity index will also be shown on the plans. Any Contractor owned RAP that is allowed to be used on the project shall remain the property of the Contractor, while stockpiled, and shall not be intermingled with State owned RAP stockpiles. Any unused Contractor owned RAP material shall be

5 removed from the project site upon completion of the project. Any unused State owned RAP shall be returned to the stockpile as directed by the Engineer. (c) Fine Aggregate. The fine aggregate shall be of uniform quality throughout. When specified on the plans, certain fine aggregate may be allowed, required or prohibited. However, a maximum of 15 percent of the total virgin aggregate may be field sand or other uncrushed aggregate, unless a value less than 15 percent is shown on the plans. All fine aggregate except for field sand shall be supplied from sources whose coarse aggregate meets the Los Angeles abrasion and magnesium sulfate soundness loss requirements shown in Table 1. Fine aggregate stockpiles shall meet the following gradation requirements, when tested in accordance with Test Method Tex-200-F, Part II. Percent by Weight Passing the 3/8 inch sieve 100 Passing the No. 8 sieve Passing the No. 200 sieve 0-30 Unless otherwise shown on the plans, gravel fine aggregate, except for field sand, shall not be allowed. Crushed gravel fine aggregate, when allowed, shall be the result of crushing aggregate that was originally retained on the No. 4 sieve. (2) Mineral Filler. Mineral filler shall consist of finely divided mineral matter such as crusher fines, lime or cement. The use of fly ash will not be allowed. At the time of use, it should be sufficiently dry to flow freely and essentially be free from clumps and foreign matter and have a linear shrinkage not greater than 3.0 percent. The mineral filler shall be proportioned into the mix through a closed system that is not affected by climatic conditions and that maintains a constant supply of material. The point of introduction of the mineral filler shall minimize loss of material through the exhaust system. The measuring device for adding mineral filler shall be tied into the automatic plant controls so that the supply of mineral filler will be automatically adjusted to plant production and provide a consistent percentage to the mixture. When tested in accordance with Test Method Tex-200-F (Part II), the mineral filler shall meet the following gradation requirements, unless otherwise shown on the plans. Percent by Weight or Volume Passing the No. 30 sieve Passing the No. 80 sieve Not less than 75 Passing the No. 200 sieve Not less than 55 (3) Baghouse Fines. The addition of fines collected by the baghouse or other air cleaning or dust collecting equipment is permitted. The measuring device for adding baghouse fines shall have controls which will allow adjustment of feed rates to match plant production rate adjustments. Baghouse fines are not required to meet the gradation requirements of mineral filler

6 (4) Asphaltic Material. (a) Mix Binder. Asphalt cement for the paving mixture shall be of the performance grade (PG) shown on the plans and shall meet the requirements of Item 300, "Asphalts, Oils and Emulsions". The Contractor shall notify the Engineer of the source of the asphaltic material prior to design of the asphaltic mixture. This source shall not change during the course of the project without the authorization of the Engineer. Should the source of asphaltic material be changed, the Engineer may require that the moisture resistance of the new material combination be evaluated to verify that the requirements of Subarticle 5.(1) are met. (b) Tack Coat. Emulsions should not be used as a tack coat unless directed by the Engineer. Asphaltic materials shall meet the requirements of Item 300, "Asphalts, Oils and Emulsions". (5) Additives. Additives to facilitate mixing and/or improve the quality of the asphaltic mixture or tack coat shall be used when noted on the plans or may be used with the authorization of the Engineer. 4. Paving Mixtures. The paving mixtures shall consist of a uniform mixture of aggregate, hot asphalt cement and additives, if allowed or required. An asphalt mixture design is a laboratory process that includes the determination of the quantity of the asphalt binder and the individual aggregates, the development of the job mix formula, and the testing of the combined mixture. The Contractor shall develop the mix design in accordance with Test Method Tex-204-F, (Part IV). Project materials may be sampled by either the Engineer or the Contractor. The samples may be obtained at the plant or quarry, as determined by the Engineer. Quarry samples shall be from materials produced for the project. Using these samples, the Contractor shall develop a job mix formula, which conforms to the requirements herein. (1) Paving Mixtures. The target laboratory molded density is 96.0 percent at the design number of gyrations. The design number of gyrations shall be N des = 100 unless otherwise shown on the plans. (2) Fatigue Resistant Paving Mixtures. When shown on the plans, a fatigue resistant pavement layer shall be designed with a target laboratory molded density of 98.0 percent at a design number of gyrations N des = 50. When this mixture is specified, all bonus and penalty requirements for both production and placement are waived and the following requirements made. During production testing the laboratory molded density shall not vary from the target density by more than ± 1.0 percent. If two consecutive test results vary by more than 1.0 percent, production shall cease until approved by the Engineer. In place roadway air voids shall be targeted at 3.0 percent and shall not vary by more than ± 1.5 percent. If two consecutive test results vary by more than 1.5 percent, placement shall cease until approved by the Engineer. 5. Job Mix Formula. A job mix formula (JMF) identifies the combined aggregate gradation and lists the percentage of each material component to be used in the mix. The JMFs are described in the following sections

7 (1) Development of Laboratory Mixture Design (JMF 1). JMF 1 is the laboratory mixture design developed by the Contractor's Level II certified specialist in accordance with Test Method Tex-204-F (Part IV). JMF 1 shall use the project aggregates, asphalt material and any other additives that are allowed or required. All mixture properties shall conform to the requirements specified in Table 2 as determined in accordance with the Test Methods in Table 7. The mixture proposed for use shall be evaluated for moisture susceptibility in the mixture design stage by Test Method Tex-531-C, unless waived on the plans or Hamburg Wheel Testing is required. Mixture approval criteria shall be in accordance with Item 301, "Asphalt Antistripping Agents". Test Method Tex-530-C will be required for production verification. Unless otherwise shown on the plans, the Contractor may select either lime or a liquid antistripping agent to reduce the moisture susceptibility of the aggregate. The addition of these antistripping agents shall be in accordance with Item 301, "Asphalt Antistripping Agents". The Engineer may waive testing for moisture susceptibility if a similar design using the same materials has proven satisfactory. When the antistripping additive type and rate are shown on the plans, then all moisture susceptibility testing requirements for mixture design will be waived. When it is suspected that there is significant difference between the specific gravities for the individual aggregates, then the specific gravity shall be determined for all aggregates. If the specific gravity values differ by or more, the mixture design shall be by volume. Whenever a minimum high temperature binder grade of PG 76 is required, the mixture proposed for use shall meet the Hamburg Wheel Test requirements of Test Method Tex- 242-F as indicated below. A split or replicate sample of the mixture used to mold the test specimen passing the Hamburg Wheel Test will be tested using ftp://ftp.dot.state.tx.us/pub/txdot-info/mat/testing/mtp.pdftest Method Tex-530-C. This tested sample will be maintained by the Engineer as a reference sample to compare to future field tests. When future field tests results indicate that the mixture is not performing as originally tested, the Engineer will perform additional Hamburg Wheel Testing during production to verify compliance. When the production sample fails the Hamburg Wheel Test criteria, production shall cease until further Hamburg Wheel tests meet the specified values. Unless otherwise shown on the plans, the Contractor may select either lime or a liquid antistripping agent to meet the Hamburg Wheel Test requirement. When antistrip agents are added at the plant, they shall be introduced in accordance with Item 301, "Asphalt Antistripping Agents." The Contractor and Engineer's responsibilities for development and approval of JMF 1 are as follows: (a) Contractor Responsibilities. The Contractor shall provide the Superpave Gyratory Compactor (SGC) to be used for mixture design verification and all production testing. The Contractor's SGC shall be located in the Engineer's on-site laboratory and will be available for use by both the Engineer and the Contractor for design verification and/or production testing. The Contractor shall develop JMF 1 in accordance with Test Method Tex-204-F (Part IV) and Subarticle 5.(1) above and submit to the Engineer all required worksheets and computer files. In the JMF 1 transmittal letter, the Contractor shall indicate if the moisture susceptibility

8 verification and Hamburg testing is to be conducted on trial batch or lab produced mixtures. When the nuclear gauge is used for determining the asphalt content, then calibration samples prepared by the Contractor during the laboratory mixture design shall be retained by the Contractor for later use as necessary. The Contractor shall notify the Engineer of any changes in material sources. If a source changes at any point, a new laboratory mixture design shall be required unless otherwise approved by the Engineer. The Engineer may request a new laboratory mixture design if the asphalt material grade or formulation is changed. (b) Engineer Responsibilities. The Engineer should use the Contractor's SGC to mold specimens for mixture design verification and production testing. If the Engineer elects not to use the Contractor's SGC for production testing, the Engineer must provide a SGC at the plant site unless otherwise approved by the Contractor. The Engineer will review the Contractor's mix design report and verify conformance with all aggregates, asphalt, additives and mixture specifications within two (2) working days of JMF 1 paper design submission. JMF 1 will be approved following satisfactory completion of all required testing noted below. If the Contractor elects to verify the Moisture Susceptibility or Hamburg Wheel Test based on laboratory specimens, then all required test results will be reported within ten (10) working days from submission of the JMF 1 paper design and delivery of all required materials. Further verification of JMF 1 is based on plant produced mix in accordance with Subarticle 5.(2). If the Contractor elects to verify the Moisture Susceptibility or Hamburg Wheel Test based on plant produced trial batch specimens, the Engineer will authorize production of the trial batch. Verification of JMF 1 will be in accordance with Subarticle 5.(2). All required test results will be reported within ten (10) working days of receipt of trial batch materials. All required testing will be conducted on samples prepared by the Engineer. (2) Verification of JMF 1. The Contractor shall use the proposed JMF 1 to provide a plant produced trial mixture for use in design verification testing, approval of JMF 1 and the development of JMF 2. The trial mixture should be of sufficient quantity to ensure that a representative mixture is produced. All equipment and materials used in production of trial mixture shall be those proposed for the project. When the plant is moved or a new plant is to be used, a new trial batch is required. All materials, labor and equipment furnished by the Contractor for the production of the trial mixture are subsidiary to the bid item for hot mix and will not be paid for directly. The Engineer will sample and test to verify JMF 1 as follows: Design Requirement Mixture Source Tolerance Limit Combined Aggregate Gradation Requirements Trial Batch Table 2 and Table 3 Asphalt Content Trial Batch % from Target

9 Design Requirement Mixture Source Tolerance Limit Laboratory Molded Density Trial Batch % from Target VMA Trial Batch Table 2 (Production) Moisture Susceptibility Trial Batch or Lab Mix 1 Item 301, or as shown on plans Hamburg Wheel Test Trial Batch or Lab Mix 1 < 20,000 rep. 2 1 As determined by Contractor. 2 Test will be performed at 122 F for mixture placed within the top four (4) inches of the pavement structure. If JMF 1 does not meet the requirements listed above, the Contractor shall produce additional trial mixtures, subject to the provisions of this Article. These tests may be subject to referee testing as described in Subarticle 5.(3). (3) Referee Testing. Referee testing, when requested, will be used to resolve differences between the Engineer and the Contractor when these differences exceed the allowable values shown in Table 4. In addition to the properties shown in Table 4, when the Engineer's tensile strength ratio or tensile strength for moisture conditioned specimens fails requirements and the Contractor's results meet requirements, referee testing is allowed. Referee test results will be provided within ten (10) working days from receipt of samples at the referee laboratory. The Hamburg Wheel testing will be performed by the Construction Division and will not be subject to referee testing. (4) Development of JMF 2. JMF 2 is the adjusted JMF that results from the trial batch and is used during the first day of production prior to beginning Lot 1. When JMF 1 is approved, the Contractor shall evaluate the test results of the trial batch and determine the optimum mixture proportions for JMF 2. The Engineer will approve JMF 2 within one (1) working day, provided that it meets the master grading limits shown in Table 2, the operational tolerance of JMF 1 for gradation listed in Table 3 and the asphalt content is within percent of JMF 1. See Subarticle 9.(2) concerning first day of production prior to beginning Lot 1. (5) Development of JMF 3. JMF 2 will be used to develop JMF 3. Plant adjustments may be made during production of Lot 1 in order to develop JMF 3. Acceptance of the material will be in accordance with Article 9. Pay adjustments for Lot 1 will be in accordance with Article 11. The Contractor and the Engineer will test Lot 1 in accordance with Article 9. Differences between the Contractor's and the Engineer's test results must be within the tolerances listed in Table 4. If the difference exceeds the values listed in Table 4, the Contractor and the Engineer must resolve the differences prior to beginning Lot 2 At the end of production of Lot 1, the Contractor shall submit JMF 3 to the Engineer. The Engineer will approve the JMF 3 provided that it meets the master grading limits shown in Table 2 and meets the operational tolerance of JMF 2 for gradation listed in

10 Table 3, and that the asphalt content is within ± 0.5 percent of JMF 2. JMF 3 must be such that the target lab density can be achieved. (6) Job Mix Formula Adjustment. The Contractor may adjust the job mix formula prior to beginning a new lot provided that it meets the master gradation limits shown in Table 2 and the operational tolerance of JMF 2 for the gradation listed in Table 3. The new job mix formula must be such that, the target lab density shown in Article 4, Paving Mixtures can be achieved. 6. Equipment. At any time during the project, the Contractor may submit for the Engineer's approval a new laboratory mixture design as detailed in Subarticle 5.(1). Unless otherwise approved by the Engineer, plant produced trial mixes will be required to verify the new laboratory mixture design as described in Subarticle 5.(2). (1) General. All equipment for the handling of all materials, mixing, placing and compacting of the mixture shall be maintained in good repair and operating condition. In case of equipment malfunction, the Contractor shall cease production until defective equipment is repaired or replaced. (2) Mixing Plants. Automatic proportioning devices shall be required for all plants and documentation as to their accuracy may be required. If a liquid or emulsified additive is to be introduced into the asphaltic material at the mix plant, it shall be added to the asphalt line at the required rate by means of an in-line metering device. The Contractor shall demonstrate that the meter meets the requirements of Item 520, "Weighing and Measuring Equipment". An in-line blending device is required to disperse the additive into the asphaltic material. A sampling port shall be provided on the asphalt line near the outlet of the additive blending device so that the modified asphaltic material may be sampled. The measuring, blending and sampling equipment and its location must be approved by the Engineer. (3) Fuel. When using fuel oil heavier than grade No. 2 or when using waste oil, the Contractor shall ensure that the fuel delivered to the burner is at a viscosity of 100 SSU or less, when tested in accordance with Test Method Tex-534-C. This viscosity ensures complete combustion of the fuel. Higher viscosities may be allowed by the Engineer if recommended by the burner manufacturer. If necessary, the Contractor shall preheat the oil to maintain the required viscosity. The Contractor shall provide means for obtaining a sample of the fuel just prior to entry into the burner in order to perform the viscosity test. The Contractor shall perform this test or provide a laboratory test report that will establish the temperature of the fuel necessary to meet the viscosity requirements. There shall be an in-line thermometer to check the temperature of the fuel delivered to the burner. Regardless of the burner fuel used, the burner or combination of burners and types of fuel used shall provide for complete combustion of the fuel and shall not leave any fuel residue adhering to the heated aggregate

11 (4) Surge-Storage System and Scales. A surge-storage system may be used to minimize the production interruptions during the normal day's operations. A device such as a gob hopper or other device designed to prevent segregation in the surge-storage bin shall be used. The mixture shall be weighed upon discharge from the surge-storage system. When a surge-storage system is used, scales shall be standard platform truck scales or other equipment such as weigh hopper scales and shall conform to Item 520, "Weighing and Measuring Equipment". If truck scales are used, they shall be placed at a location approved by the Engineer. If other weighing equipment is used, the Engineer may require mass checks by truck scales for the basis of approval of the equipment. Temporary storing or holding of the hot mix asphalt by the surge storage system will be required for drum mix plants during the normal day's operation. Overnight storage will not be permitted unless authorized on the plans or in writing by the Engineer. (5) Recording Device and Record Printer. The mixture shall be weighed for payment. If a surge-storage system is used, an automatic recording device and a digital record printer shall be provided to indicate the date, project identification number, vehicle identification, total mass of the load, tare mass of the vehicle, the mass of asphaltic mixture in each load and the number of loads for the day, unless otherwise indicated on the plans. When surge-storage system is not used, batch weights will be used as the basis for payment and automatic recording devices and automatic digital record printers in accordance with Item 520, "Weighing and Measuring Equipment", shall be required. (6) Laboratory. The Contractor shall establish, maintain and operate a laboratory. When approved by the Engineer, the Contractor may furnish a laboratory of sufficient size and capacity to accommodate both Engineer's and Contractor's testing operations and with an area of approximately 720 square feet. In any case, the laboratory shall be equipped to perform the tests indicated in this specification. All quality control testing shall be performed at the Contractor's on-site laboratory. All test equipment at the laboratory shall be calibrated and certified in accordance with Test Method Tex-237-F or the manufacturer's recommendations. The Engineer will verify that all the necessary equipment, materials and current test procedures are present and that all equipment meets these requirements prior to the production of hot mix asphalt. 7. Stockpiling, Storage and Feeding of Materials. (1) Stockpiling. Stockpiling operation shall be in accordance with Section 2.(3)(a). (2) Storage and Heating of Asphalt Materials. The asphalt material storage capacity shall be ample to meet the requirements of the plant. Asphalt shall not be heated to a temperature in excess of that specified in Item 300, "Asphalts, Oils and Emulsions". All equipment used in the storage and handling of asphalt material shall be kept in a clean condition at all times and shall be operated in such a manner that there will be no contamination with foreign matter. The heating apparatus shall be equipped with a continuously recording thermometer and a 24 hour chart that will record the temperature of the asphalt material at the location of the highest temperature. Continuous recordings shall be made for asphalt material and hot mix asphalt temperatures. These recordings shall be made available to the Engineer on a daily basis

12 Asphalt heated in excess of that specified in Item 300 shall be cause for ceasing operations as determined by the Engineer. The Engineer may require that the asphalt be retested for compliance prior to resuming production. Failure to provide properly recorded chart temperatures as specified above shall be cause for a charge of $1,000 per day of non-compliance and will be deducted from the Contractor's estimate. (3) Scalping Screen. A scalping screen of a maximum aperture opening approved by the Engineer shall be required after the cold feeds and ahead of the combined aggregate belt scales. (4) Plants Using RAP. If RAP is used, a separate cold bin shall be required. The RAP feed system shall be equipped to remove particles over two (2) inches in size prior to the weighing device. There shall be adequate cold bin controls to provide a uniform amount of RAP to the mixture Positive weight measurement of RAP shall be provided by the use of belt scales or other approved devices or methods. RAP shall be mixed and blended so that there is no evidence of unseparated particles in the mixture as it leaves the plant. 8. Construction Methods. (1) General. It shall be the responsibility of the Contractor to produce, transport, place and compact the specified paving mixture in accordance with the requirements herein. If at any time, prior to placement on the roadway surface, the temperature of the mixture falls below 212 F, the quantity of that mixture shall be determined to the satisfaction of the Engineer and removed from the project at the expense of the Contractor and no payment will be made for the mixture that is removed. At any time the temperature of the mixture falls below the following minimum placement temperatures and the Contractor elects to place the mixture, the limits of that mixture placed shall be determined and the Contractor shall be required to core the section as directed by the Engineer. If the air void determination of the cores is more than 10.0 percent or less than 3.0 percent, then the mixture shall be removed and replaced at the expense of the Contractor. Asphalt Grade PG 64 PG 70 PG 76 PG 82 Minimum Placement Temperature (Prior to Paver) 240 F 260 F 280 F 290 F (2) Adverse Weather Condition. Unless otherwise approved by the Engineer, the asphalt mixture, or tack coat shall not be placed when air temperature is below 50 F and is falling, but it may be placed when the air temperature is above 40 F and is rising. If a mixture is placed on a wet or damp surface, its location shall be marked for reference. If it does not bond to the existing pavement, ravels, or has other surface irregularities,

13 the mixture shall be removed or repaired to the satisfaction of the Engineer and at the expense of the Contractor. (3) Tack Coat. Tack coat shall be used at the direction of the Engineer. The surface upon which the tack coat is to be placed shall be cleaned thoroughly to the satisfaction of the Engineer. A uniform application of tack coat shall be applied at a rate not less than 0.04 or more than 0.07 gallons of residual asphalt material per square yard of surface area. All contact surfaces of curbs and structures and all joints shall be painted with a thin, uniform application of tack coat. During the application of tack coat, care shall be taken to prevent splattering of adjacent pavement, curb and gutter and structures. The tack coat shall be rolled with a pneumatic tire roller when directed by the Engineer. Prior to paving, the Contractor should verify that the tack coat has adequate adhesive properties. The Engineer may suspend paving operations until adequate adhesion is achieved. (4) Transporting Hot Mix. The hot mix shall be hauled to the work site in tight vehicles previously cleaned of all foreign material. Any transporting operation that results in contamination of hot mix with foreign materials will not be allowed. Truck beds shall be enclosed with waterproof tarpaulins. The sides of the truck beds shall be insulated to a minimum value of R-4. The Contractor shall provide documentation to show that the trucks used on the project meet the R-4 insulation requirements. Only approved release agents may be used to coat the inside surfaces of truck beds. A list of approved release agents will be available through the Engineer's office. (5) Windrow Pick-Up Equipment. Windrow pick-up equipment shall be operated in a manner such that substantially all the mixture deposited on the roadbed is picked up and loaded into the spreading and finishing machine. The mixture shall not be contaminated with foreign material. The equipment shall be designed so that, without resorting to hand finishing, it does not interfere with the spreading and finishing machine in obtaining the required line, grade and surface. (6) Remixing. When remixing is required in accordance with Subarticle 9.(8), the material transferred from the hauling unit shall be remixed prior to placement. Remixing shall be accomplished by pugmill or variable pitch augers operating with a laydown machine hopper insert or other system approved by the Engineer. (7) Placing. The hot mix shall be dumped and spread on the approved prepared surface with a spreading and finishing machine. When properly compacted, the finished pavement shall be smooth, of uniform texture and density and shall meet the requirements of the typical cross sections and the surface tests. In addition, the placing of the hot mix shall be done without tearing, shoving, gouging or segregating the mixture and without producing streaks in the mat. Adjacent to flush curbs, gutters and structures, the surface shall be finished uniformly high so that when compacted, it will be slightly above the edge of the curb or structure. Construction joints of successive courses of asphaltic material shall be offset at least six (6) inches. Construction joints on surface courses shall coincide with lane lines or shall be as directed by the Engineer

14 (8) Compacting. The pavement shall be compacted thoroughly and uniformly with the necessary rollers to obtain the air voids and cross section of the finished paving mixture meeting the requirements of the plans and specifications. The Contractor shall make adjustments to the compaction operation, mix design, or other processes to ensure that problems are not encountered which could adversely affect the quality of the finished mat. Mix design adjustments may include redesigning with different materials. The Contractor shall measure mat density of the longitudinal joint in accordance with Section 9.(6)(c). The edges of the pavement along curbs, headers and similar structures or in such locations that will not allow thorough compaction with the rollers shall be thoroughly compacted with lightly oiled tamps. The Engineer may require rolling with a trench roller on widened areas, in trenches and in other limited areas With the exception of the above requirements, and when specific air void requirements have not been voided by plan note, the type and size of compaction equipment and the rolling patterns used will be entirely at the discretion of the Contractor. Where specific air void requirements are voided, one (1) three-wheel roller and one (1) tandem roller shall be furnished for each compaction operation except as provided below or as approved by the Engineer. The use of a tandem roller may be waived by the Engineer when the surface is already adequately smooth and further steel-wheel rolling is shown to be ineffective. With approval of the Engineer, the Contractor may substitute a vibratory roller for the three-wheel roller and/or the tandem roller. Use of pneumatic tire rollers will not be allowed if excessive pickup of fines by roller tires occurs. Additional or heavier rollers shall be furnished if required by the Engineer. Rolling patterns that achieve maximum compaction shall be established by the Contractor as outlined in Test Method Tex-207-F, (Part IV). For these conditions there will be no pay adjustment factor for in-place air voids. (9) Opening to Traffic. The compacted pavement shall not be opened to traffic until the mat temperature has cooled to 160 F, unless otherwise directed by the Engineer. 9. Acceptance Plan. (1) General. Acceptance of the hot mix will be based on the acceptance plan described herein. Random sampling of the hot mix shall be performed on a lot and sublot basis. If the production or placement pay factor for three (3) consecutive lots is below 1.000, then the Contractor shall cease production until test results, or other information, indicate to the satisfaction of the Engineer that the next material to be produced will meet the specified values. (2) Production Lot. The Engineer will select the lot size. A production lot shall consist of four (4) equal sublots. The maximum sublot size shall be 1,000 tons or 650 cubic yards. Lot size can only be changed prior to the beginning of a lot. The first 2,000 linear feet of mix placed during the first day of production prior to beginning Lot 1, will be paid for at the unit price bid, provided that it meets the

15 operational tolerances of JMF 2, listed in Table 3. Any mix placed in this area not meeting the required tolerances may remain in place as determined by the Engineer. Payment for said production shall be at a pay adjustment if retained. However, if any one (1) of the operational tolerances shown in Table 3 are exceeded by a factor of two (2), then the mixture shall be removed and replaced at the Contractor's expense. (a) Small Production Quantities. When the anticipated daily production is less than 500 tons, the Engineer may elect to either waive all sampling and testing requirements or follow the acceptance plan described in Subarticle 9.(2). If the Engineer elects to waive sampling and testing, both production and placement pay factors will be If the Engineer elects to follow the acceptance plan described in Subarticle 9.(2) and this results in less than four (4) sublots for the job, pay adjustment will be in accordance with Section 9.(2)(b), "Incomplete Lots". (b) Incomplete Lots. If a lot is begun but cannot be completed such as on the last day of production or in other circumstances deemed appropriate by the Engineer, the lot may be closed out by the Engineer. Payment for this lot will be adjusted in accordance with Subarticle 11.(2). (3) Production Sampling. All sampling locations shall be determined by the random sampling procedure defined in Test Method Tex-225- F. The Engineer is responsible for establishing the random sample locations before lot production begins. Only the locations of the sample that will be taken by the Contractor will be disclosed to the Contractor. The Contractor shall provide a sampling platform approved by the Engineer. Hot mix shall be obtained from trucks at the plant in accordance with Test Method Tex- 222-F. For each sublot, the Contractor shall take one (1) sample at the location randomly selected by the Engineer. Additionally, for each lot, the Engineer will randomly select at least two- (2) sublots and take one (1) random sample from each selected sublot. Each sample will be split by the sampler into three (3) equal portions in accordance with Test Method Tex-200-F. These portions will be labeled as Contractor, Engineer and Referee and will be delivered to the appropriate party's laboratory. Referee samples shall be delivered to the Engineer. Unused samples will be discarded after the Contractor accepts pay adjustment factors for that lot. (4) Production Testing. The Contractor and Engineer share production testing responsibility. The Engineer will determine lab density for each sublot, and the Contractor has the option to verify Engineer's test results on split samples provided by the Engineer. The Contractor shall determine compliance with operational tolerance on all sublots and the Engineer will verify Contractor's test results. The Contractor can request referee testing should the difference between the Contractor's and the Engineer's test results exceed the values shown in Table 4. All production testing by both the Engineer and the Contractor must be completed and reported within one (1) working day of completion of the sublot. (a) Lab Density. Density is a mixture design and pay factor parameter. The lab density is determined by the Engineer for each sublot using the SGC. It is determined in accordance with Test Methods Tex-207-F, Tex-241-F and Tex

16 F. When the Engineer obtains a sample from a sublot in accordance with Subarticle 9.(3), that sample will be used by the Engineer to determine the laboratory bulk specific gravity and the maximum theoretical specific gravity and to calculate the lab density. For sublots not sampled by the Engineer, the Contractor's split sample will be used by the Engineer to determine laboratory bulk specific gravity and maximum theoretical specific gravity and to calculate lab density. (b) Gradation Test. Gradations shall be determined in accordance with Test Method Tex-200-F. Aggregates for gradation determination are obtained from one (1) of the following three (3) methods: extraction (Tex-210-F) cold feed/hot bin samples (Tex-229-F) ignition oven (Tex-236-F) When cold feed samples are used for gradation testing, the Contractor shall supply a correlation as outlined in Tex-229-F. Correlation factors shall be verified by the Contractor and approved by the Engineer once every five (5) production days. Gradation testing shall be conducted by the Contractor for each sublot on samples taken by the Contractor. The Engineer will verify that the operational tolerances for gradation shown in Table 3 have been met. The minimum verification frequency will be one (1) Engineer's sample for every 12 sublots. (c) Asphalt Content. The asphalt material content shall be determined in accordance with Test Method Tex-228-F or Tex-236-F. Asphalt content testing shall be conducted by the Contractor for each sublot on samples taken by the Contractor. The Engineer will conduct asphalt content testing on Engineer's samples on a minimum of one (1) for every four (4) sublots. If the asphalt content exceeds the operational tolerance shown in Table 3 on two (2) consecutive sublots per lot based on the Engineer's test results or two (2) consecutive sublots per lot based on the Contractor's test results no production or placement bonus will be paid for that lot. Production of mixture to the project shall cease if the Asphalt Content deviates from the current Job Mix Formula by more than 0.5 percent for any sublot. Production may resume when test results or other information indicate, to the satisfaction of the Engineer, that the next mix to be produced will be within the allowable tolerance. (d) Moisture Susceptibility. Production verification testing of moisture susceptibility will use Test Method Tex-530-C and is required when anti-stripping additives are used. The Engineer will determine the location and frequency of sampling and will perform the test. If the testing indicates that the required level of resistance to moisture damage is not being achieved in the plant mixture, production shall cease until trial production indicates that the problem has been corrected

17 (e) Mixture Enhancement. Production verification testing of mixture enhancement will use Test Method Tex-530-C and is required when additives such as lime or liquid anti-strips are used. The Engineer will determine the location and frequency of sampling and will perform the test. If the testing indicates that the required level of enhancement is not being achieved in the plant mixture, Hamburg Wheel Testing, when required, will be performed. Failure to meet Hamburg Wheel Test criteria shall be cause for operations to cease. (f) Operational Tolerances. The hot mix shall meet operational tolerances shown in Table 3 for each sublot. When either the Contractor's or the Engineer's test results exceed the operational tolerances shown in Table 3 for three (3) consecutive tests for a single property, then the Contractor shall cease production until test results or other information indicate, to the satisfaction of the Engineer, that the next material to be produced will meet the specified values. The Contractor shall select and report to the Engineer in writing the target discharge temperature of the mixture based on the binder manufacturer's recommended mixing temperature. The asphalt mixture, when discharged from the mixer, shall not vary from this selected temperature more than 25 F. Any mixture produced at a temperature in excess of 350 F will not be paid for nor allowed to be placed on a TxDOT project. Additionally, hot mix should not be produced at temperatures that exceed those allowed by local environmental regulatory agencies. (g) Individual Loads of Hot Mix. The Engineer can reject individual loads of hot mix in the truck. When a load of hot mix is rejected for reasons other than temperature as stated in Subarticle 8.(1), the rejected load will be tested at the request of the Contractor. This request must be made within four (4) hours of rejection. If tests are within operational tolerances, payment will be made for the load. If test results are not within operational tolerances as shown in Table 3, no payment will be made for the load. The Engineer will perform sampling and testing. (5) Placement Lot. A placement lot shall consist of the area placed in a production lot, excluding miscellaneous areas. A placement sublot shall consist of 1/4 of the area of the placement lot. (a) Incomplete Placement Lots. An incomplete placement lot shall consist of the area placed in an incomplete production lot as described in Subarticle 9.(2)(b) excluding miscellaneous areas. For these lots, one (1) placement sample location will be selected for each production sublot placed. (b) Miscellaneous Areas. Areas that are not generally subject to primary traffic such as driveways, mailbox turnouts, crossovers, gores and other similar areas are considered to be miscellaneous areas. The area placed during the first 2,000 linear feet of the first day's production is also a miscellaneous area. Shoulders and ramps are not considered miscellaneous areas. Miscellaneous areas are the only areas that are not eligible for random placement sampling locations and will be assigned placement pay factor (c) Level-Ups and Thin Overlays. For the purpose of calculating placement pay adjustment factor, level-ups and thin overlays will be considered as miscellaneous