florida department of transportation 1 overview of cqc asphalt specifications

Florida Department of Transportation 1

Overview of CQC Asphalt Specifications

Florida Department of Transportation

• 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

In a Nutshell..


• 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

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

Basics


Typical 1,000 ton Sublot50 truckloads (20 tons each)


Random Sample Numbers by Sublot

3Verification Sublot

Plant

1000

Sublot

1

2

3

1133

2696

37284

QC Samples

(tons)

Tons/sublot:

487


Plant

1000

Sublot

1

2

3

1133

2696

37284

QC Samples

(tons)

Tons/sublot:

487

1- 1

387- 1- 1- 2

37

2310

64

85

3836

Offset (ft)

101081311

6

11

3423

1

3649

2553275428763022

- 31

1

- 3- 4- 5

3347

2332

- 3

11711368- 2

- 1- 1

473

2051

973714

- 1- 1

- 2- 2- 2

1

1

- 3

- 4- 4

11

1

11

- 3

- 3

1

1

- 2- 2

142116781881 2

- 493

1 - 4

- 2

- 2

- 3

- 3

111

- 3

- 5

Density Cores

- 5- 1

11

- 4- 4

- 4

- 4

- 5- 1

1

CORE ID# (tons)

1071

- 1387- 1

- 1- 2

37

2310

64

85

3836

Offset (ft)

101081311

6

11

3423

1

3649

2553275428763022

- 31

1

- 3- 4- 5

3347

2332

- 3

11711368- 2

- 1- 1

473

2051

973714

- 1- 1

- 2- 2- 2

1

1

- 3

- 4- 4

11

1

11

- 3

- 3

1

1

- 2- 2

142116781881 2

- 493

1 - 4

- 2

- 2

- 3

- 3

111

- 3

- 5

Density Cores

- 5- 1

11

- 4- 4

- 4

- 4

- 5- 1

1

CORE ID# (tons)

107


QC Testing at Plant

Sublot 2 Sublot 3 Sublot 4Sublot 1

487 26961133 3728Tons:

LOT = 4,000 Tons

QC randomly tests one per sublotVT randomly tests one split per LOT

RT splits held until LOT is verified


Sample Splits

Gmb Gmm Ext/Grd

QC

VT

RT


• 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

Roadway Acceptance 334-5.4.3

1- 1

338- 1- 1- 2

11

91

6104

87

96

1

3962

Offset (ft)

273596

3

- 1

3476

1

3640

2558275428983169

- 31

- 2

- 3- 4- 5

3376

2372

- 3

10371393- 2

1

- 1

505

2007

802606

- 1- 1

- 2- 2

1

1

- 3

- 4- 4

11

1

1

- 3

- 3

1

1

- 2- 2

147116551932 4

- 419

1 - 4

- 2

- 2

- 3

- 3

111

- 3

- 5

Density Cores

- 5- 1

11

- 4- 4

- 4

- 4

- 5- 1

CORE ID# (tons)

541


In-Place Density testing required everywhere

EXCEPT

Density Testing 334-5.1


Density Testing Exceptions 334-5.1.2

• 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

NO TESTING REQUIRED IN AREAS LESS THAN 1,000 FEET LONG:• Turning lanes• Acceleration lanes• Deceleration lanes• Shoulders• Parallel parking lanes• Ramps


Table 334-5 Master Production RangeCharacteristic Tolerance(1)

Asphalt Binder Content (%) Target ± 0.55Passing No. 200 Sieve (%) Target ± 1.50

Air Voids (%) 2.30 – 6.00Density, (minimum %Gmm)(2) 90.00

(1) Tolerances for sample size of n = 1 from verified mix design(2) Based on an average of 5 randomly located cores

Master Production Range


• 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

Quality Control Test


• At completion of each LOT– The LOT is “CLOSED”

• VT sample is tested for randomly selected sublot– Split from QC Sample

Verification Testing 334-5.5


Plant

1000

Sublot

1

2

3

1133

2696

37284

QC Samples

(tons)

Tons/sublot:

487


Plant

1000

Sublot

1

2

3

1133

2696

37284

QC Samples

(tons)

Tons/sublot:

487




LOT = 4,000 Tons

QC tests on per sublot

VT randomly tests one split per LOTUse test method precision for comparison


Table 334-6 Between-Laboratory Precision Values

Property Maximum DifferenceGmm 0.016Gmb (gyratory compacted samples) 0.022Gmb (roadway cores) 0.015Pb 0.44 percentP-200 FM 1-T 030 (Figure 2)P-8 FM 1-T 030 (Figure 2)

Between-Laboratory Precision Values


• If Verification compares to QC– Calculate pay based on QC results



• If Verification does not compare to QC– Resolution testing – District Materials Office



Resolution Testing 334-5.6


487 26961133 3728Tons:

LOT = 4,000 Tons

QC randomly tests one per sublot

VT randomly tests one split per LOT

RT tests non-comparison property for each sublot


• 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

Resolution Testing 334-5.6


• Resolution compares to ALL QC data– Calculate pay based on QC results

Resolution Compares to QC


• 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.

Resolution Does Not Compare


• Composite Pay Factor:– 35% Density– 25% Air Voids– 25% AC Content– 10% P-200

– 5% P-8

Composite Pay Factor 334-8


• 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

Minimum Acceptable Quality Levels 334-5.9


• 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

Independent Verification Testing 334-5.7


Independent Verification Testing 334-5.7

IV Passes MPR

Continue Production

IV MPR Failure

No Contractor

Split

Address Problem

Contractor Split

PC Compares

Address Problem

PC Does Not Compare

Check Sample Check Compares

to IV

Check Does Not Compare to IV

Continue Production

IV Failure


• 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)

Friction Course 337


QUESTIONS/COMMENTS?

florida department of transportation 1 overview of cqc asphalt specifications

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