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I F I T & D C T C o n t r a c t o r ’ s E x p e r i e n c e

E x p e r t T a s k G r o u p M e e t i n gF a l l s R i v e r M a y 8 t h 2 0 1 8

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O u t l i n e

• Durability tests Status

• I-64 Pilot Project Illinois - IFIT Experience • BMD Illinois Specifications & Status• IFIT – Illinois Test Procedure 405• Issues encountered

• Pilot Project I-80 Centre County, PA• Conclusions

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4-point Bending

AASHTO T 321

S-VECDAASHTO TP107

Texas Overlay Tex-248-F

DCT ASTM D7313

SCB Low T°AASHTO TP 105

SCB Jc Int. T°ASTM D8044

SCB IFITAASHTO TP 124

IDTNflex

- Slab – 4 cuts- Studs + LVDTs

- drill + slice - Studs + LVDTs

- 4 cuts,- Glue on plate

- 3 cuts, 1 notch, holes

- Studs, clip gage

- 3 cuts,1 notch- 3 Studs, 1

extensor, 1 clip gauge

- 9 cuts,3 notches

- 3 Studs, 1 extensor, 1 clip gauge

3 cuts,1 notch 2 Cuts

COV > 50% ? 30-50% 10-15% 20% 20% 20% 10-15%

> 1 week > 1 week 2-3 days 3-4 days 1 day > 1 day

> $100K $100K $50K $50K $50K $20K $20K $10K

D u r a b i l i t y / C r a c k i n g E v a l u a t i o n

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In Place Preparation

1. Volumetrics + Performance

2. Performance Modified Volumetrics

HLWT + OTHLWT

+ SCB

APA + OTHLWT

+ IFIT

HLWT + ?

HLWT +

IFIT

HLWT +

IFIT?

APA + ?

B a l a n c e d M i x D e s i g n A p p r o a c h e s

HLWT + ?

DCT

NCAT NCHRP 20-07 Task 406

HLWT + DCT

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I - 6 4 P i l o t P r o j e c t I l l i n o i s - I F I T E x p e r i e n c e

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B M D I l l i n o i s S p e c i f i c a t i o n s

Superpave Volumetric Design with Performance Verification

• Performance is approved in the design process

• Verified during test strip

• Failure will result in the contractor ceasing production until passing results are obtained

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B M D S p e c i f i c a t i o n S t a t u s

• Currently in pilot project stage• Each district identifies two projects per year to be IFIT specified

• Prior to 2017 • Run completely as informational

• Results gathered from test strips

• Required to core roadway for in place data generation

• 2017 – 2019• IFIT results on pilot projects can lead to ceasing production

• 2020 - Forward• IFIT full implementation on all projects

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I F I T - I l l i n o i s Te s t P r o c e d u r e 4 0 5

• Equipment, Tests Parameters & Specimens preparation Method Machine device Support rollers Loading

headDisplacement

controlLoading

rateData rate

Specimens Temp

TP 124 Electro-mechanical, screw, servo-hydraulic, 10 kN(res. of 20 N)

U-shaped supports, spring loaded.25-mm D

12.5 mm radius

Internal control or external LVDT, 0.01 mm resolution

50 ± 1 mm per minute, linear

20 Hz -Spec: 160 mm 4 1/2 sp. 7.0 ±0.5%-Notches: 15.0 (±0.1)x 1.5 (± 0.1) mm

25°C

IL 405 Servo-hydraulic unless screw-driven can give similar results, 10 kN (res. of 5 N)

- Method A: bearing supports. 25-mm D120-mm distance maintained- Method B: U-shaped supports, spring loaded;

12.5 mm radius

Internal control or external LVDT, 0.01 mm resolution

50 ± 1 mm per minute, linear

20 Hz -Spec: 160 mm 4 x1/2 sp. 7.0 ±0.5%-Spec: 115 mm 2 x 1/2 sp. 7.0 ±0.5%-Notches: 15.0 (±0.1) x 1.5 (± 0.05) mm

25°C

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I F I T - I l l i n o i s Te s t P r o c e d u r e 4 0 5

• Aging Protocols

Hours of total oven time, neat binders (290-300F), PMAs (300 – 310F)

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I l l i n o i s Te s t P r o c e d u r e 4 0 5

• Reporting Calculations

From data generated in house this reduces the average COV• COV of 4 – 21.2%• COV of 3 – 11.8%

But causes the FI to change randomly

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I D O T R o u n d R o b i n R e s u l t s – 3 0 L a b o r a t o r i e s

N50 C Surface Mix (Design PG 64-22)Asphalt Grade Total Asphalt Content ABR VMA VFA RAP

PG 58-28 5.8% 31.0% 15.0% 73.3% 32.5%

• Round 1 distributed cut samples• Round 2 distributed compacted samples, contractor cut • Round 3 distributed mix, contractor compacted and cut

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I - 6 4 P i l o t P r o j e c t

6.3 Miles - 52,000 tons

- 22,516 tons intermediate- 15,900 tons Surface Mix- 14,424 tons Shoulder Mix

Paved from July to September 2017

Pay factors:- Air voids & VMA on plate samples- Density- Smoothness.

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I 6 4 B i n d e r D e s i g n V e r i f i c a t i o n

y = 18.694x - 85.562R² = 0.8118

0

2

4

6

8

10

12

14

16

4.85 4.9 4.95 5 5.05 5.1 5.15 5.2 5.25 5.3 5.35

FI

Asphalt Content

19mm N90 Binder Design

Design AC Vs IFIT

Delta Design Value

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D e s i g n s C o m p a r i s o n s t o I D O T

C90 D70 LB70 LB90 64 LB90 760

4

8

12

16

20

24

28

32

FI

Mix Types

Delta vs IDOT Design FI Resultswith 2Stdev error bars

Delta

IDOT

Mix Delta FI 2*Stdv Delta COV IDOT FI 2*Stdv IDOT COVC90 9 2.844 15.8% 21.7 10.7632 24.8%D70 14.3 3.575 12.5% 11.4 6.0648 26.6%LB70 10.7 3.0816 14.4% 12.7 3.4036 13.4%

LB90 64 16.1 1.8354 5.7% 15.6 0.3432 1.1%LB90 76 9.4 1.8048 9.6% 10 0.8 4.0%

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D e s i g n v s P r o d u c t i o n V e r i f i c a t i o n R e s u l t s

Test Design Production*

19mm N90 Polymer modified Binder course

HWT 3.6 2.8

IFIT 8.4 3.47

9.5mm N90 Polymer modified Surface Course

HWT 3.1 4.6

IFIT 13.59 11.8

9.5mm N30 Shoulder Surface

HWT - -

IFIT 20.36 28.6

* First individual plate sample tests results

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T E S T I N G C O M P A R I S O N S

Design Test Strip Resample Day 3 Lab Day 40

4

8

12

16

20

24

FI

Delta vs IDOT FI Results (B90 binder course poly) with 2Stdev error bars

Delta FI 2*Stdv Delta COV IDOT FI 2*Stdv IDOT COVDesign 11.85 4.67 19.7% 8.45 0.86 5.1%

Test Strip 3.68 1.02 13.8% 3.47 0.50 7.3%Resample 7.95 0.70 4.4% 7.75 1.14 7.4%

Day 3 6.04 1.44 11.9% 7.17 2.44 17.0%Lab 17.2 2.96 8.6% 12.32 1.73 7.0%

Day 4 12.44 1.99 8.0% 16.79 5.96 17.7%

IDOT

Delta

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I m p a c t o f v a r i a t i o n s r e p o r t i n g

FI Values12.99 11.34 25.41 12.62

Population FI 15.59

Population COV 42.2%

Reported FI 12.32COV 7.0%

High Minus Avg 9.82

Avg Minus Low 4.25

Removal reduces COV substantiallyFI values are closely grouped. Taken from I 64 Binder course, Lab made

FI Values

8.44 9.83 6.01 7.06

Population FI 7.84

Population COV 21.2%

High Minus Avg 1.99

Avg Minus Low 1.83

Reported FI 7.17

COV 17.0%

I-64 resample after first shutdown. Truck pulled. Had the low value been 0.17 lower test would have passed.Population FI is more accurate as there really isn’t an outlier

Counter FI 8.44

COV 16.4%

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R e s e a r c h R e p o r t N o . F H W A - I C T - 1 7 - 0 1 2

Increase the number of replicates to a minimum of six to eight.

Removing the lowest or highest values from a dataset of four, reduces the COV, but is accompanied by random changes in the FI.

Recommended that the number of replicates be increased to a six to achieve a better representation of the material and improve reproducibility

The study does not recommend the use of any of the sample reduction techniques unless a data point is proven to be an outlier. (PTM 04…)

4.1.2 Determination of Optimum Sample Size

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I m p a c t o f p o i n t o f s a m p l i n g S i t e ( C o n t r a c t o r R e s u l t s )

Tests FI of 4 COV of 4 FI of 3 COV of 3

Lab (design) 24 17.17 19.5% 17.09 10.5%

Plate* 19 8.9 22.6% 8.8 13.5%

Truck** 128 20.3 22.4% 20.6 12.6%

*Plate samples were all B90 mix** Truck samples often came from samples retained over various lengths of time and exposed to elements

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I m p a c t A g i n g o n F l e x i b i l i t y I n d e x ( c o n t r a c t o r r e s u l t s )

• Used C90 virgin mix• Four replicates per conditioning

time (16 specimens)

• Conditioning times used 0, 1, 2, 3, 4 and 5 hours

• Aging time is considered time at compaction temperature of 295°F

y = -4.3871x + 26.304R² = 0.8572

0.0

5.0

10.0

15.0

20.0

25.0

30.0

35.0

40.0

0 1 2 3 4 5FI

Conditioning Hours

Conditioning Hours Vs FI

Hours 0 1 2 3 4 5

COV Pop 27.0% 21.0% 28.0% 32.6% 27.1% 20.9%

COV Avg 3 17.1% 14.6% 13.0% 16.9% 17.3% 13.2%

Impact of sampling point and time

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M i x T y p e ( C o n t r a c t o r r e s u l t s )

Tests FI of 4 COV of 4 FI of 3 COV of 3 Min Max

Binder 19.0mm 41 10.20 22.5% 10.00 12.5% 3.6 27.8

C Surface 9.5mm 80 21.9 21.7% 22.5 12.4% 5.5 54.4

Friction Surface 9.5mm 33 24.8 19.7% 25.1 11.3% 6.0 38.0

Level Binder 9.5mm FG 17 12.6 21.5% 12.1 11.1% 7.4 47.3

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B i n d e r G r a d e

Mix Tests FI of 4 COV of 4 FI of 3 COV of 3

B90 64-22 13 13.4 27.2% 13.7 16.4%

B90 76-22 19 8.9 22.6% 8.8 13.5%

LB90 64-22 3 15.8 15.3% 15.9 4.2%

LB90 76-22 3 10.4 20.3% 9.6 7.7% 0.0 4.0 8.0 12.0 16.0

B90

LB90

FI

Binder Type Vs FI

76-22

76-22

64-22

64-22

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B 9 0 F I C o m p a r i s o n P e r B i n d e r

0

0.5

1

1.5

2

2.5

3

3.5

0 1 2 3 4 5 6 7

Load

(kN

)

Displacement (mm)

PG76-22 Vs PG64-22

B90 PG76-22

B90 PG64-22

PG76-22 – 6.0 secPG64-22 – 7.2 Sec

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B i n d e r G r a d e C o n t i n u e d

0 4 8 12 16 20 24

C30

C70

B70

FI

Binder Type & RAP % vs FIMix AC Type RAP % ABR% FI

C3064 10 7 20.36

58 25 21.2 18.5

C7064 20 15 14.2

58 25 21.2 19.7

B7064 20 19 7.1

58 25 21.4 10.6

58-28

58-28

64-22

64-22

58-28

64-22

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R A P C o n t e n t

Tests FI of 4 COV of 4 FI of 3 COV of 3

C90 Virgin 2 27.6 31.3% 27.2 19.5%

C90R ~15% 16 14.8 23.4% 14.2 12.9%

C90R ~20% 4 9.5 25.8% 9.0 15.8%

y = -0.9011x + 27.33R² = 0.9986

0

5

10

15

20

25

30

0 5 10 15 20 25

FI

RAP %

RAP Content Vs FI

RAP Content Vs FI

IDOT Results

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• Pennsylvania Long Life Asphalt Pavement- Bid July, 2017

- 2” mill and overlay on I-80 - 92,000 tons bituminous overlay

• 47,000 tons of 9.5mm SRL”E” SMA 76-22• 18,000 tons of 9.5mm SRL”H” 3<10 ESAL (100 gyration) 76-

22

• 21,500 tons of 9.5mm 100 gyration ½” minimum scratch course 76-22

• Other misc. tons of 19mm and 9.5mm• Approximately 24,000 tons to be completed by September

30, 2017

• Performance testing on SMA design and production

P i l o t P r o j e c t I - 8 0 C e n t r e C o u n t y , P A

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• 2017: 10,000 tons SMA placed

• Design Performance Testing: DCT, SCB TP105, IFIT, Texas Overlay Testing, and Rutting Susceptibility in AASHTO Materials Reference Laboratory

• + PSU SCB : 5 mm /min, 20°C, target air voids 5.5%

• Aging : 135°C for 24 h 4 h

• Verification: 126 roadway cores taken on the SMA (density, ac / gradation, Gmm T209, companion, 2 performance testing )

P i l o t P r o j e c t I - 8 0 C e n t r e C o u n t y , P A

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C O N C L U S I O N S

• SCB-IFIT I-64 experience demonstrate that multiple factors can affect significantly the results

Need to understand what impacts FI (mix characteristics, but also short term aging,results reporting, repeatability…)The current specifications should factor this uncertainty (shut downs)

Not all mixes should have the same requirement (FI)These points apply to other performance tests as well

• DOTs need to open specifications too allow contractors to balance mix based on innovation(additives, equipment…)

• Need to correlate performance tests to field performance and / or materials fundamentalproperties