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Overview of CQC Asphalt Specifications

Overview of CQC Asphalt Specifications. In a Nutshell. Payment based on Contractor’s Quality Control tests FDOT runs verification tests at a lesser frequency Payment is based on roadway density, air voids, asphalt content and gradation Uses Percent Within Limits (PWL) statistical specs

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Overview of CQC Asphalt Specifications

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  1. Overview of CQC Asphalt Specifications

  2. In a Nutshell.. • Payment based on Contractor’s Quality Control tests • FDOT runs verification tests at a lesser frequency • Payment is based on roadway density, air voids, asphalt content and gradation • Uses Percent Within Limits (PWL) statistical specs • Separate Master Production Range to catch outliers • Began with July 2002 workbook

  3. Basics • Standard Lot size: • 2,000 or 4,000 tons for dense mix or 2,000 tons for OGFC • Four sublots per LOT • Plant LOT & Roadway LOT are the same • Engineer establishes sampling points • Random basis • Use Excel spreadsheet • Directs Contractor when to sample • Contractor does all the sampling

  4. Basics • QC = Quality Control = Contractor • VT = Verification Test = FDOT Project personnel (typically a consultant) • IV = Independent Verification = FDOT District Materials personnel • RT = Resolution Testing = FDOT District Materials personnel

  5. Typical 1,000 ton Sublot 50 truckloads (20 tons each)

  6. Random Sample Numbers by Sublot

  7. QC Testing at Plant LOT = 4,000 Tons Sublot 2 Sublot 3 Sublot 4 Sublot 1 Tons: 487 1133 2696 3728 QC randomly tests one per sublot VT randomly tests one split per LOT RT splits held until LOT is verified

  8. Gmb Gmm Ext/Grd Sample Splits QC VT RT

  9. Roadway Acceptance 334-5.4.3 • Roadway and Plant LOT the same • 6-inch diameter cores • Five cores per sublot • Randomly located (stratified manner) • Minimum of 3 cores/sublot • Retain QC cores for VT & RT • Only part of the testing that is done on the same sample

  10. Density Testing 334-5.1 In-Place Density testing required everywhere EXCEPT

  11. Density Testing Exceptions 334-5.1.2 NO TESTING REQUIRED IN AREAS LESS THAN 1,000 FEET LONG: • Turning lanes • Acceleration lanes • Deceleration lanes • Shoulders • Parallel parking lanes • Ramps • FC-5 • Total quantity of hot mix < 2,000 tons • Widening or shoulders with a width of 5 ft or less • Misc. Asphalt, Variable thickness or overbuild layers • Leveling, Bridge Decks, Approach slabs • First lift of asphalt placed on subgrade • Bike/shared use paths • Crossovers or intersections • Any course thickness < 1 inch or specified spread rate converts to < 1 inch

  12. Master Production Range

  13. Quality Control Test • If Quality Control Test Does Not Meet Tolerances: 334-5.4.4 (for MPR) Terminate LOT if: • One sublot failure for air voids • One average sublot density failure • Two consecutive sublot failures for gradation or asphalt binder content

  14. Verification Testing 334-5.5 • At completion of each LOT • The LOT is “CLOSED” • VT sample is tested for randomly selected sublot • Split from QC Sample

  15. Verification Testing 334-5.5 LOT = 4,000 Tons Sublot 2 Sublot 3 Sublot 4 Sublot 1 QC tests on per sublot VT randomly tests one split per LOT Use test method precision for comparison

  16. Between-Laboratory Precision Values

  17. Verification Testing 334-5.5 • If Verification compares to QC • Calculate pay based on QC results

  18. Verification Testing 334-5.5 • If Verification does not compare to QC • Resolution testing – District Materials Office

  19. Resolution Testing 334-5.6 LOT = 4,000 Tons Sublot 2 Sublot 3 Sublot 4 Sublot 1 Tons: 487 1133 2696 3728 QC randomly tests one per sublot VT randomly tests one split per LOT RT tests non-comparison property for each sublot

  20. Resolution Testing 334-5.6 • Resolution samples tested by third party lab for the property in question • All sublots are tested for the failed property • Use test method precision and the master production range

  21. Resolution Compares to QC • Resolution compares to ALL QC data • Calculate pay based on QC results

  22. Resolution Does Not Compare • Resolution does not compare to QC data • This only has to happen for one comparison • Resolution results are used to calculate pay for that property • If application of Resolution test data results in a failure to meet the MPR, address as defective material.

  23. Composite Pay Factor 334-8 • Composite Pay Factor: • 35% Density • 25% Air Voids • 25% AC Content • 10% P-200 • 5% P-8

  24. Minimum Acceptable Quality Levels 334-5.9 • Individual Pay Factors Below 0.90 • First time -> correct the problem • 2 consecutive -> cease production • Composite Pay Factor 0.80 to 0.89 • Cease until problem is resolved • Composite Pay Factor 0.75 to 0.79 • Address defective material per 334-5.9.5 • Composite Pay Factor Less than 0.75 • Remove and Replace defective LOT at no cost to the Department

  25. Independent Verification Testing 334-5.7 • District Materials Office • One sample per 4,000 tons • Roving IV = 1 / 2,000 tons • Sampled by Contractor with FDOT supervision • Use Master Production Range Table 334-5 • ONE IV MPR failure -> address failure and/or cease production • Contractor has option to test a split sample (PC) • Compare IV results with PC (test precision) • IV does not affect pay calculation

  26. Independent Verification Testing 334-5.7 Continue Production IV Passes MPR Address Problem IV MPR Failure No Contractor Split Contractor Split Check Sample Check Compares to IV PC Compares PC Does Not Compare IV Failure Check Does Not Compare to IV Continue Production Address Problem

  27. Friction Course 337 • FC 9.5 and FC 12.5 • Handled in same manner as 334 HMA • FC 5 (OGFC) • Same concepts but different material properties: • Asphalt content & Gradation (P-3/8, P-4, P-200)

  28. Questions/Comments?

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