Presentation on theme: "Asphalt Quality Assurance Program"— Presentation transcript:
1 Asphalt Quality Assurance Program Rob Crandol, P.E. – Statewide Asphalt Program Manager AsphaltRegional Meetings
2 INDEPENDENT ASSURANCE (IA) QUALITY ASSURANCEPROCESS CONTROL (QC)INDEPENDENT ASSURANCE (IA)ACCEPTANCE (VST)In order to be effective, QA must include the functions of process control, acceptance and independent assurance. All three of these QA functions provide measurement data on the quality of the materials or construction under consideration. Measurement is an important component of the continuous management functions in a total quality management (TQM) system. The value of measurement results depends entirely on how well conceived and executed is the measurement in the first place. Since the specifications stipulate the procedures to be followed and the tests to be run, well thought out, rationally developed specifications are important ingredients for quality improvement. The relationship among process control, acceptance and independent assurance varies from agency to agency, primarily depending on their experience in QA specifications. The one constant that must be present is the necessity for clearly stating which party is responsible for each function.
3 Contractor – Performs QC VDOT – Performs IA & VST Asphalt QA ProgramContractor – Performs QCVDOT – Performs IA & VSTAsphalt Certification schools for contractors, inspectors and testing personnel.Plant CertificationField 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 211Mix DesignContractor provides QC testingSection 315Mix PlacementContractor provides Field Control - EquipmentDensity 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 placementInspection – observationsSplit sample testsEvaluations of TechniciansAASHTO Materials Reference Laboratory
6 Verification Sampling and Testing (VST) Validate the quality of the productPerformed by VDOTVST 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.PlantVDOT uses independent samplesField
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.
11 Asphalt Plant QAVDOT uses the Contractor’s test data (QC) in the acceptance of plant produced Asphalt mixtures
12 Producer Samples and Tests (QC) Perform Gradation and Asphalt Content testing randomly every 500 tonsTemperature Measurements 1st and 5th load then at least once an hourVolumetric SUPERPAVE tests every 1,000 tonsAir 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 – IASplit sample tests for gradation and Asphalt Content are used for system wide IA and VST purposesVolumetrics 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)
15 VST 3 IA1 2 1 4 Lot 2 Lot 3 Lot 1 Lot 4 IA3 IA2 IA4 QC System ComparisonNon Matched ComparisonVST
16 4.4 4.6 4.8 5.0 5.2 5.4 5.6 Asphalt Content f(x) Comparison Reports Lab #1Lab #22.214.171.124.05.25.45.6Asphalt Contentf(x)Populations of data can have different means or averages but have the same standard deviations.
17 4.4 4.6 4.8 5.0 5.2 5.6 5.8 Asphalt Content f(x) Comparison Reports Populations can have different standard deviations or variabilities and have the same mean (average)
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.
22 Contractor Field QC Testing Depth ChecksCross SlopeStraight Edge Transverse JointsQC Density testing either by Thin Lift Nuclear gauge or through cores/plugsJoint DensityTest and Test frequency will be determined by Road & Bridge Specifications, Special Provisions or as directed by the EngineerCut plugs for VST at direction of Materials QA technician.
23 VDOT Project Staff Responsibilities IA Verifies Paving equipment meets specificationsVerifies materials being used are from approved sourcesTake Temperature measurements of AC at least every hourVerifies that contractor personnel are performing QC operations correctlyVerifies Density testing being performedJoint Density
25 VDOT/Materials VST and IA Perform VST testing on plugsIA testingVerify method of random selectionMarking of test locationsObserve QC testing at control stripObserve test sections.Obtain samples of cores from control strip to reweigh in laboratory.Depth Control tests
26 Asphalt Density Virginia Test Method VTM-76 Stratified Random Locations - QCControl StripTest SectionsCores for Control Strips - IA6 cores for new mixes2 cores per site2 cores
27 STRATIFIED RANDOM LOCATIONS 1000 ft.5000 FEET1000 FOOT SECTIONSTEST SECTION
40 MINIMUM DENSITY REQUIREMENT (Bulk Specific Gravity / Max Specific Gravity) * 100(Table III-3)
41 TABLE III-3 Density Requirements Mixture TypeMin. ControlStrip Density (%)SM-9.5A, 12.5A92.5SM-9.5D, 12.5D92.2SM-9.5E, 12.5EIM-19.0AIM-19.0D BM-25.0 92.2Note: The control strip density requirement is the percentage oftheoretical maximum density at the job-mix formula asdetermined by Superpave Mix Design.
42 Nuclear GaugeCalibratedSame gauge used at Control Strip
43 QC Density Test Section 1 J2 J3 J4 J5 J6 J7 J8 J9 J10 J591372104681 J2 J3 J4 J5 J7 J9 J10 J6 J8 J5000 FEETTAKE READINGS AT LEAST 1 FOOT FROM EDGE OF PAVEMENTAverage of 10 readings (98 – 102% of control strip)Density Readings 4 or 6 inches from the Joint
44 QC Density Test Section 1 J2 J3 J4 J5 J6 J7 J8 J9 J10 J591372104685000 FEETTAKE READINGS AT LEAST 1 FOOT FROM EDGE OF PAVEMENTAverage of 10 readings (98 – 102% of control strip)Density Readings 4 or 6 inches from the Joint
45 Contractor must cut 2 cores for VST at the direction of VDOT Select one Test Section for VSTLot 1Lot 2Lot 3Lot 4Lot 5Contractor must cut 2 cores for VST at the direction of VDOT
46 VST Density Test Section 15937VSTR-VSTVST210R-VST68R-VST45000 FEETCUT 2 CORESReferee Procedure - Cut 3 more Coresuse average of all 5 for final decision
47 Determine Limits Lot 13 Lot 14 Lot 15 Lot 16 Lot 17 Preceding After Failing
48 Asphalt Quality Assurance Program Rob Crandol, P.E. – Statewide Asphalt Program Manager AsphaltRegional Meetings