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Asphalt Quality Assurance Program

Asphalt Quality Assurance Program. Rob Crandol , P.E. – Statewide Asphal t Program Manager Asphalt Regional Meetings. QUALITY ASSURANCE. INDEPENDENT ASSURANCE (IA). PROCESS CONTROL (QC). ACCEPTANCE (VST). Asphalt QA Program. Contractor – Performs QC VDOT – Performs IA & VST

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Asphalt Quality Assurance Program

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  1. Asphalt Quality Assurance Program Rob Crandol, P.E. – Statewide Asphalt Program Manager Asphalt Regional Meetings

  2. QUALITY ASSURANCE INDEPENDENT ASSURANCE (IA) PROCESS CONTROL (QC) ACCEPTANCE (VST)

  3. Asphalt QA Program • Contractor – Performs QC • VDOT – Performs IA & VST • Asphalt Certification schools for contractors, inspectors and testing personnel. • Plant Certification • Field Certification

  4. Quality Control (QC) • All activities performed to control the quality of the asphalt mixture during production and placement to fulfill the contractor requirements. • Section 211 • Mix Design • Contractor provides QC testing • Section 315 • Mix Placement • Contractor provides Field Control - Equipment • Density Testing

  5. Independent Assurance (IA) • Activities that are an unbiased and an independent evaluation of all Operations, sampling and testing procedures, and equipment used in the acceptance program. • VDOT provides IA during production and placement • Inspection – observations • Split sample tests • Evaluations of Technicians • AASHTO Materials Reference Laboratory

  6. Verification Sampling and Testing (VST) • Validate the quality of the product • Performed by VDOT • VST should determine if the material is acceptable per specification. • VDOT uses split samples plus a statistical process of examining Contractor QC test data to verify the accuracy of sampling and testing used in the acceptance decision. • Plant • VDOT uses independent samples • Field

  7. Mix Design Approval Process • Contractor submits mix design laboratory data and forms to VDOT for initial approval. • Limited production - contractor can produce up to 500 tons or one day’s production. Gyratory samples taken and analyzed by both VDOT and Contractor for compliance with Specification requirements and conformance to submitted mix design. • Full production approval granted after a successful limited production trial.

  8. Asphalt Plant Quality Control

  9. Random Truck Sampling

  10. Sample Splitting

  11. VDOT uses the Contractor’s test data (QC) in the acceptance of plant produced Asphalt mixtures Asphalt Plant QA

  12. Producer Samples and Tests (QC) • Perform Gradation and Asphalt Content testing randomly every 500 tons • Temperature Measurements 1st and 5th load then at least once an hour • Volumetric SUPERPAVE tests every 1,000 tons • Air Voids (VTM) • Voids in Mineral Aggregate (VMA) • Voids filled with Asphalt (VFA) • Rice test – Maximum Specific Gravity (Gmm)

  13. VDOT Responsibilities, Samples and Tests • Inspect Plant equipment and lab for compliance with specifications – IA • Split sample tests for gradation and Asphalt Content are used for system wide IA and VST purposes • Volumetrics SUPERPAVE tests used for verification purposes. • Air Voids (VTM) • Voids in Mineral Aggregate (VMA) • Voids filled with Asphalt (VFA) • Rice test – Maximum Specific Gravity (Gmm)

  14. Independent Assurance Lot 1 Lot 2 Lot 3 Lot 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 Sample Comparison IA1 IA2 IA3 IA4 Matched Comparison Analysis QC 4 3 4 2 IA1 IA2 IA3 IA4 IA

  15. VST Lot 1 Lot 2 Lot 3 Lot 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 IA1 IA2 IA3 IA4 QC 1 2 3 1 2 4 1 2 3 1 3 4 IA1 IA2 IA3 IA4 VST Non Matched Comparison System Comparison

  16. Comparison Reports f(x) 4.4 4.6 4.8 5.0 5.2 5.4 5.6 Asphalt Content Lab #1 Lab #2

  17. Comparison Reports f(x) 4.4 4.6 4.8 5.0 5.2 5.6 5.8 Asphalt Content

  18. Asphalt MITS - PLAID Reports • Statistical Tests are performed on both Split Comparison and IA Samples. • Any non comparison must be investigated, resolved and documented.

  19. Assessment of Random Samples Is this random?

  20. Summary – Asphalt Plant QA • Statistics is the tool that VDOT uses to verify the quality of asphalt mixtures.

  21. Asphalt Field Quality Assurance

  22. Contractor Field QC Testing • Depth Checks • Cross Slope • Straight Edge Transverse Joints • QC Density testing either by Thin Lift Nuclear gauge or through cores/plugs • Joint Density • Test and Test frequency will be determined by Road & Bridge Specifications, Special Provisions or as directed by the Engineer • Cut plugs for VST at direction of Materials QA technician.

  23. VDOT Project Staff Responsibilities IA • Verifies Paving equipment meets specifications • Verifies materials being used are from approved sources • Take Temperature measurements of AC at least every hour • Verifies that contractor personnel are performing QC operations correctly • Verifies Density testing being performed • Joint Density

  24. VDOT/Materials VST and IA • Perform VST testing on plugs • IA testing • Verify method of random selection • Marking of test locations • Observe QC testing at control strip • Observe test sections. • Obtain samples of cores from control strip to reweigh in laboratory. • Depth Control tests

  25. Asphalt DensityVirginia Test MethodVTM-76 • Stratified Random Locations - QC • Control Strip • Test Sections • Cores for Control Strips - IA • 6 cores for new mixes • 2 cores per site • 2 cores

  26. STRATIFIED RANDOM LOCATIONS 1000 ft. 5000 FEET 1000 FOOT SECTIONS TEST SECTION

  27. ROLLER PATTERN CONTROL STRIP NUMBER OF PASSES TARGET DENSITY 75 ft. 300 ft.

  28. TEST THREE LOCATIONS 50 FEET 1 3 2 75 FEET MARK TEST LOCATIONS ORIENT GAUGE IN SAME DIRECTION

  29. 144.0 143.0 DENS I TY 142.0 141.1 140.0 (lb/ft3) 139.0 138.0 137.0 136.0 135.0 DENSITY vs NUMBER OF PASSES 1 2 3 4 5 6 7 8 NUMBER OF PASSES

  30. Locations of nuclear readings are marked by contractor. VTM-76

  31. CONTROL STRIP 1 5 9 3 7 2 10 6 8 4 300 FEET TAKE READINGS AT LEAST 1 FOOT FROM EDGE OF PAVEMENT Using 5 roller passes

  32. Core locations are marked for cutting. VTM-76

  33. Cores are cut … VTM-76

  34. …and carefully removed. VTM-76

  35. MINIMUM DENSITY REQUIREMENT (Bulk Specific Gravity / Max Specific Gravity) * 100 (Table III-3)

  36. Mixture Type Min. Control Strip Density (%) SM-9.5A, 12.5A 92.5 SM-9.5D, 12.5D 92.2 SM-9.5E, 12.5E 92.2 IM-19.0A 92.2 IM-19.0D 92.2 BM-25.0 92.2 TABLE III-3 Density Requirements Note: The control strip density requirement is the percentage of theoretical maximum density at the job-mix formula as determined by Superpave Mix Design.

  37. Nuclear Gauge Calibrated Same gauge used at Control Strip

  38. QC Density Test Section 1 J 2 J 3 J 4 J 5 J 6 J 7 J 8 J 9 J 10 J 5 9 1 3 7 2 10 4 6 8 1 J 2 J 3 J 4 J 5 J 7 J 9 J 10 J 6 J 8 J 5000 FEET TAKE READINGS AT LEAST 1 FOOT FROM EDGE OF PAVEMENT Average of 10 readings (98 – 102% of control strip) Density Readings 4 or 6 inches from the Joint

  39. QC Density Test Section 1 J 2 J 3 J 4 J 5 J 6 J 7 J 8 J 9 J 10 J 5 9 1 3 7 2 10 4 6 8 5000 FEET TAKE READINGS AT LEAST 1 FOOT FROM EDGE OF PAVEMENT Average of 10 readings (98 – 102% of control strip) Density Readings 4 or 6 inches from the Joint

  40. Select one Test Section for VST Lot 1 Lot 2 Lot 3 Lot 4 Lot 5 Contractor must cut 2 cores for VST at the direction of VDOT

  41. VST Density Test Section 1 5 9 3 7 VST R-VST VST 2 10 R-VST 6 8 R-VST 4 5000 FEET CUT 2 CORES Referee Procedure - Cut 3 more Cores use average of all 5 for final decision

  42. Determine Limits Lot 13 Lot 14 Lot 15 Lot 16 Lot 17 Preceding After Failing

  43. Asphalt Quality Assurance Program Rob Crandol, P.E. – Statewide Asphalt Program Manager Asphalt Regional Meetings

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