Plant Mix Bituminous Paving

Plant

  1. Determine if bituminous mixtures are to be produced in accordance with Plant Mixed Bituminous Pavement 2360 and review the Special Provisions of the contract.
  2. Specification 2360 requires mixtures be produced from a certified plant. Familiarize yourself with plant equipment, checking for specifications compliance. Review schematic of plant or site map.
  3. Certification procedure
    The contractor shall:
    • Complete application and request for plant inspection.
    • Provide a site map of stockpile locations.
    • Monitor calibration of plant equipment (pumps, aggregate bins, etc.)
    • Pass plant and testing facility inspection by having the Plant Monitor and Bituminous Plant Authorized Agent to complete and sign the Asphalt Plant Inspection Report (TP 02142-02 and TP 02143-02). By signing the Asphalt Plant Inspection Report, the HMA plant authorized agent agrees to calibrate and maintain equipment within allowable tolerances set forth in these specifications and the MnDOT Bituminous Manual. 
    • Obtain a Mixture Design Report prior to production.
  4. Identify items to be sampled, rates of sampling and testing (Materials Control Schedule), and source or access for securing samples.
  5. Review Mixture Design Report in both the lab and at the plant for current percentages.
  6. Check that Contractor is obtaining the required aggregate samples and performing the necessary tests.
  7. Know and ensure proper mix and asphalt temperatures.
  8. Observe mix appearance to ensure uniformity and identification of possible plant malfunction.
  9. Observe stockpiles for possible contamination in storing and handling.
  10. Ensure truck boxes are clean and protected against buildup yet free of excessive cleaning agents. No petroleum distillates are allowed as releasing agents.
  11. Observe loading of trucks to ensure segregation is not occurring and that trucks are covered when necessary.
  12. Proper scale procedures shall be followed. Weigh tickets are to be completely and properly filled out, and automatic scale printer operations are to be properly monitored. A full list of what is required on the weigh tickets is found in the 2360 spec. Make sure Contractor is performing weekly scale checks.
  13. Monitor Asphalt shipments for contract compliance and that the Contractor is obtaining that necessary asphalt samples.
  14. If bituminous mixtures are being provided in accordance with 2360 Plant Mixed Bituminous Pavement, monitor Contractor’s testing to ensure that the required number of tests are done and that the proper procedures are followed.
    • Review Contractor’s on-site quality control records and charts for accuracy and completeness.
    • Monitor Agency tests and confirm that they are within the allowable tolerances for Contractor and Agency tests.
  15. Monitor the weighing of cores, observe the saturated surface dry and immersed weight of cores.
  16. Check that the Contractor is maintaining plant report and daily records that may include such things as hours of operation, production, asphalt delivered, shutdowns (and reasons therefore), mix adjustment, temperature, and any other events or circumstances having impact on production or product.
  17. Take or observe the taking of random verification samples (minimum one per mix per day). Retain half of sample for Agency testing and provide the Verification companion to the Contractor for testing. Deliver Verification sample to Agency Lab. Verification companions must be tested by the Contractor.
  18. Observe maximum specific gravity (Gmm) (Rice test).
  19. Observe bulk specific gravity (Gmb).

Paving

  1. Check equipment for compliance with specifications. Familiarize self with operation and various functions of equipment.
  2. Familiarize self with adjustments available on pavers such as flow gates, auger control, tamper bar, screed angle, screed vibration, and screed crown. 
  3. Identify areas of instability that require repair.
  4. Ensure the surface is free of loose or excess material and free of dust from milling operations. Multiple passes of the broom may be required.
  5. Check grade for smoothness, compactness, cross slope, grade, and alignment as appropriate.
  6. Discuss paving and rolling sequence with Contractor.
  7. Observe tack placement for uniform and complete coverage and specified application rate over a clean and dry surface.
  8. Collect, check, and initial each delivery ticket.
  9. Inspect mixture for possible deficiencies observed by physical appearance.
  10. Observe dumping and paver feed operation for possible segregation problems.
  11. Maintain surveillance of paver operation to ensure against incorrect line, grade, or cross slope. Limit start and stopping of paving operations through coordination of plant production and mixture placement.
  12. Observe mat for uniformity of texture, presence of spot segregation, proper thickness, width, and yield.
  13. Observe breakdown roller operation for uniformity and continuity of operation with attention to speed, pattern, location of drive wheel, and vibration (if used).
  14. Maintain surveillance of the roller operation to ensure timely performance to avoid marks and bumps on the mat.
  15. Ensure adequacy and mechanical condition of rolling equipment.
  16. Check surface with 10 ft. straightedge to verify surface requirements.
  17. Cores will be taken and tested by the Contractor. Core locations will be determined and marked by the Agency. Take possession of the companion cores. Monitor density tests for compliance with requirements. The Contractor shall schedule the approximate time of testing during normal project work hours so that the Agency may observe and record the saturated surface dry and immersed weight of the cores.
  18. Maintain daily records that may include such things as hours of operation, stations paved, course, depth, width, tonnage, yield, measured delivered temperature, weather, and other events bearing on quality and quantity of work.
  19. Take or observe the taking of random verification samples (minimum one per mix per day). Retain half of sample for Agency testing and provide the Verification companion to the Contractor for testing. Deliver verification Sample to Agency lab. Verification companions must be tested by the Contractor. If for some reason Contractor does not obtain a Verification sample, the Agency should obtain a sample large enough to be tested by Contractor and Agency lab. All samples are to be put in a 12 in. concrete cylinder. For 2360 Gyratory mix obtain 3 full cylinders and put properly filled out cards in each cylinder.
  20. On a daily basis obtain Test Summary Sheets, Density Core Worksheets, Agency’s Density Core Worksheets, Agency’s Verification Results, 20-minute recordation and plant report, and keep track of the tonnage where samples were obtained for evaluating volumetric and Density compliance.

References: Specification 2331, 2340, 2350, and 2360, Bituminous Manual, Bituminous Street Inspectors Hand-book, Bituminous Plant Inspectors Hand-book, Contract Administration Manual, Schedule For Materials Control.

PAVEMENT SURFACE SMOOTHNESS (INERTIAL PROFILER)

  1. Make sure each inertial profiler has been certified by MnDOT for the current year.
  2. Ensure the operator of the inertial profiler has passed a proficiency test and possesses a current certification issued by MnDOT.
  3. Check the Special Provisions of the project that the correct ride equation(s) is/are being used for pavement surface smoothness evaluation.
  4. On the day of profiling, ensure raw data files (.kml and .ppf files) and a printout of the inertial profiler’s settings have been submitted.
  5. Within 5 days of profiling, make sure a ProVAL summary report for each lane profiled has been submitted.

Available References: Specification 2353, 2363, 2365, 2360, and 2399, Bituminous Manual, Lab Manual, Contract Administration Manual, Schedule of Materials Control.