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Overview CQC Asphalt Specifications

Overview 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 CQC Asphalt Specifications

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  1. Overview 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: • 4,000 tons for dense mix or 2000 tons for OGFC. • Four sublots per Lot. • Plant Lot & Roadway Lot 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 - composed of 50 truckloads (20 tons each)

  6. Random Sample Numbers by Sublot Lot 1, sublot 1 50 trucks, 20 tons each = 1,000 ton sublot

  7. QC Testing at Plant LOT = 4,000 Tons Sublot 1 Sublot 2 Sublot 3 Sublot 4 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. Master Production Range for Quality Control

  10. If Quality Control Test Does Not Meet Tolerances: 334-5.4.4 (for MPR) • Terminate Lot if: • One sublot failure for Air Voids. • One sublot density failure. • Two consecutive sublot density failures for fine mix. • Two consecutive sublot failures for gradation. • Two consecutive sublot failures for asphalt content. • 2 individual core densities for coarse mix less than 91.00% Gmm.

  11. Verification Testing334-5.5 • At completion of each Lot • Test VT sample for randomly selected sublot • Split from QC sample • Use test method precision for comparison • Excel spreadsheet • If everything compares favorably… • Calculate pay based on QC results • If not….go to Resolution testing • District Materials Office

  12. VT Testing LOT = 4,000 Tons Sublot 1 Sublot 2 Sublot 3 Sublot 4 QC tests one per sublot. VT randomly tests one split per Lot.

  13. Between-Laboratory Precision Values Table 334-6

  14. Resolution Testing334-5.6 • If the verification testing does not compare on a pay property • Resolution samples tested by third party lab for the property in question • All sublots are tested • Use test method precision for comparison to QC • Excel spreadsheet • If everything compares favorably… • Calculate pay based on QC results • If the sample does not compare • Resolution results are used to calculate pay for that property

  15. RT Testing LOT = 4,000 Tons Sublot 1 Sublot 2 Sublot 3 Sublot 4 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.

  16. Roadway Acceptance334-5.4.3 • Roadway and Plant Lot the same. • 6-inch diameter cores . • Five cores per sublot. • Randomly located (stratified manner). • Use spreadsheet. • Minimum of 3 cores/sublot. • Retain QC cores for VT & RT.

  17. Density Testing Exceptions334-5.1.2 • Density testing not required for: • Total quantity of hot mix < 2,000 tons. • Widening or shoulders with a width of 5 ft or less. • FC-5 • 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.

  18. Density Testing Exceptions (continued)334-5.1.2 • Testing not required for the following areas when they are less than 1,000 feet long: • Turning lanes • Acceleration lanes • Deceleration lanes • Shoulders • Parallel parking lanes • Ramps • Use rolling procedure (equipment and pattern) as approved by the Engineer. • Density testing required everywhere else.

  19. Calculate Payment334-8 • If two or less sublots: • Use Small Quantity Pay Table based on average deviations from target. • If three or more sublots: • Use Percent Within Limits (PWL) for the Lot. • Calculate Pay Factor for: • Density, Air Voids, AC Content, P-200, P-8

  20. Payment….334-8 • Pay factor for each characteristic is determined. • Composite Pay factor is based on: • 35% Density • 25% Air Voids • 25% AC Content • 10% P-200 • 5% P-8 • Calculations done by spreadsheet.

  21. Minimum Acceptable Quality Levels 334-5.9 • Individual Pay Factors Below 0.90 • First time correct, 2 consecutive – cease. • Composite Pay Factor 0.80 to 0.89 • Cease until problem is resolved. • Composite Pay Factor 0.75 to 0.79 • Handle per 334-5.9.5 (EAR). • Composite Pay Factor Less than 0.75 • Remove and Replace.

  22. Defective Material 334-5.9.5 • Contractor must remove & replace…OR • Engineering Analysis Report… • If approved by Engineer / Paid by contractor. • Independent Lab approved by Engineer. • Remain in place at composite pay factor, or as determined by Engineer. • Can be waived by Engineer. • Delineation testing by Contractor • Only for asphalt content, density, and gradation.

  23. Independent Verification Testing334-5.7 • Handled by the District Materials Office. • One sample per 4,000 tons. • Sampled by Contractor with FDOT supervision. • Compare IV results with QC (test precision). • Use Master Production Range Table 334-5. • IF IV fails MPR, cease production until problem resolved and then evaluate in-place material.

  24. 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)

  25. Questions/ Comments?

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