cracking tests for asphalt mixtures and how to mixture ...€¦ · blankenship asphalt tech &...
TRANSCRIPT
![Page 1: Cracking Tests for Asphalt Mixtures and How to Mixture ...€¦ · Blankenship Asphalt Tech & Training Cracking Tests for Asphalt Mixtures ... •Proposed that aging at 135°C causes](https://reader030.vdocument.in/reader030/viewer/2022040607/5ebdcdc89d79be23090d6a15/html5/thumbnails/1.jpg)
Phillip B. BlankenshipConsulting Engineer
Blankenship Asphalt Tech & Training
Cracking Tests for Asphalt Mixtures and How to Mixture Condition
Region 4 Topic
![Page 2: Cracking Tests for Asphalt Mixtures and How to Mixture ...€¦ · Blankenship Asphalt Tech & Training Cracking Tests for Asphalt Mixtures ... •Proposed that aging at 135°C causes](https://reader030.vdocument.in/reader030/viewer/2022040607/5ebdcdc89d79be23090d6a15/html5/thumbnails/2.jpg)
A Fun Time to Be in Asphalt
2
• Industry is demanding a cracking test
• SHRP started on cracking tests in ~1990 but never fully developed
• Binder spec (PAV DSR) was meant for unmodified binders and was a catch all
o Not stout enough for the cracking component that we need today
• Cracking tests are popping up seemingly everywhere
• Users are now in the game and notice the cracking
![Page 3: Cracking Tests for Asphalt Mixtures and How to Mixture ...€¦ · Blankenship Asphalt Tech & Training Cracking Tests for Asphalt Mixtures ... •Proposed that aging at 135°C causes](https://reader030.vdocument.in/reader030/viewer/2022040607/5ebdcdc89d79be23090d6a15/html5/thumbnails/3.jpg)
What Should Have Happened…
• Superpave required Level 1, 2, and 3 testing based on traffic (ESAL) load
o Level 1 (Volumetrics + TSR) was intended only for 1 million ESALS or less
o Level 2 and 3 were to be used for higher traffic loads and included rutting and cracking performance test
• Since we saw such good initial Superpave pavement performance in 1993-2000, Levels 2 and 3 “complication” were soon forgotten
![Page 4: Cracking Tests for Asphalt Mixtures and How to Mixture ...€¦ · Blankenship Asphalt Tech & Training Cracking Tests for Asphalt Mixtures ... •Proposed that aging at 135°C causes](https://reader030.vdocument.in/reader030/viewer/2022040607/5ebdcdc89d79be23090d6a15/html5/thumbnails/4.jpg)
The Need for Performance Testing
![Page 5: Cracking Tests for Asphalt Mixtures and How to Mixture ...€¦ · Blankenship Asphalt Tech & Training Cracking Tests for Asphalt Mixtures ... •Proposed that aging at 135°C causes](https://reader030.vdocument.in/reader030/viewer/2022040607/5ebdcdc89d79be23090d6a15/html5/thumbnails/5.jpg)
It all started in 1919
• Asphalt Association (later Asphalt Institute) was formed and hired Prevost Hubbard and Frederick Field as researchers
• Research led to the Hubbard-Field design method using rammers (like a Marshall hammer but with 2 size hammers) in mid 1920’s
AI Magazine article by Gerry Huber 2/15/2013
![Page 6: Cracking Tests for Asphalt Mixtures and How to Mixture ...€¦ · Blankenship Asphalt Tech & Training Cracking Tests for Asphalt Mixtures ... •Proposed that aging at 135°C causes](https://reader030.vdocument.in/reader030/viewer/2022040607/5ebdcdc89d79be23090d6a15/html5/thumbnails/6.jpg)
Hubbard-Field Stability
• Hubbard-Field Stability is the first known asphalt performance test.
• Sample was loaded by turning the wheel
• Dial gage recorded the maximum load
Hubbard-Field Stability test at
AI headquarters 8-2013
![Page 7: Cracking Tests for Asphalt Mixtures and How to Mixture ...€¦ · Blankenship Asphalt Tech & Training Cracking Tests for Asphalt Mixtures ... •Proposed that aging at 135°C causes](https://reader030.vdocument.in/reader030/viewer/2022040607/5ebdcdc89d79be23090d6a15/html5/thumbnails/7.jpg)
Testing Then and Now
• By the 1940’s:
o Hubbard-Field stability test
o Hveem stability test
o Marshall stability and flow
o Recorded data by hand or charts
• Today
o TSR, Hamburg wheel tracker, APA, Texas overlay tester, 4-point flexural fatigue, fracture energy (3-4 tests), resilient modulus, shear modulus, dynamic modulus, AMPT dynamic modulus/flow number, and more
![Page 8: Cracking Tests for Asphalt Mixtures and How to Mixture ...€¦ · Blankenship Asphalt Tech & Training Cracking Tests for Asphalt Mixtures ... •Proposed that aging at 135°C causes](https://reader030.vdocument.in/reader030/viewer/2022040607/5ebdcdc89d79be23090d6a15/html5/thumbnails/8.jpg)
Technology Today
• We can control test from 0.01 Hertz to 25 Hertz (25 cycles a second)
• Technology allows us to record data at fast rates like 100+ points a second
• Temperature control to the nearest 0.5C (mix) and 0.1C (binder)
o Need of strict temperature control is something we learned during the SHRP research 1987-1992.
• The problem still remains…
![Page 9: Cracking Tests for Asphalt Mixtures and How to Mixture ...€¦ · Blankenship Asphalt Tech & Training Cracking Tests for Asphalt Mixtures ... •Proposed that aging at 135°C causes](https://reader030.vdocument.in/reader030/viewer/2022040607/5ebdcdc89d79be23090d6a15/html5/thumbnails/9.jpg)
Traffic & Load Growth on RuralInterstate System
0%
100%
200%
300%
400%
500%
600%
700%
1970 1975 1980 1985 1990 1995 2000 2005
Change Since 1970
Rural Average Daily Load
Rural Average Daily Traffic
FHWA Highway Statistics 2003
![Page 10: Cracking Tests for Asphalt Mixtures and How to Mixture ...€¦ · Blankenship Asphalt Tech & Training Cracking Tests for Asphalt Mixtures ... •Proposed that aging at 135°C causes](https://reader030.vdocument.in/reader030/viewer/2022040607/5ebdcdc89d79be23090d6a15/html5/thumbnails/10.jpg)
10
Why do we need a mixture cracking test if the binder (PG 64-xx) is
certified to meet a low temperature?
![Page 11: Cracking Tests for Asphalt Mixtures and How to Mixture ...€¦ · Blankenship Asphalt Tech & Training Cracking Tests for Asphalt Mixtures ... •Proposed that aging at 135°C causes](https://reader030.vdocument.in/reader030/viewer/2022040607/5ebdcdc89d79be23090d6a15/html5/thumbnails/11.jpg)
The Basics of Performance Testing
Allow us to verify our estimates
Design and check for potential distresses
Custom design for specific loading
Think out-of-the-box with new materials and modifiers
![Page 12: Cracking Tests for Asphalt Mixtures and How to Mixture ...€¦ · Blankenship Asphalt Tech & Training Cracking Tests for Asphalt Mixtures ... •Proposed that aging at 135°C causes](https://reader030.vdocument.in/reader030/viewer/2022040607/5ebdcdc89d79be23090d6a15/html5/thumbnails/12.jpg)
Fundamental Performance Tests
• Flexural Beam Fatigue
o Brittleness
• Asphalt Mixture Performance Test
o Dynamic modulus (used in MEPDG for design)
o Flow number (rutting)
• Indirect Tension Test
o Low temperature cracking b creep compliance (resting load on cold samples) to see how the move
Photos from Asphalt Institute
![Page 13: Cracking Tests for Asphalt Mixtures and How to Mixture ...€¦ · Blankenship Asphalt Tech & Training Cracking Tests for Asphalt Mixtures ... •Proposed that aging at 135°C causes](https://reader030.vdocument.in/reader030/viewer/2022040607/5ebdcdc89d79be23090d6a15/html5/thumbnails/13.jpg)
Performance Tests
• Other tests
o Hamburg Wheel Tester
o Asphalt Pavement Analyzer
o Several energy based tests
o Overlay (crack) tester
![Page 14: Cracking Tests for Asphalt Mixtures and How to Mixture ...€¦ · Blankenship Asphalt Tech & Training Cracking Tests for Asphalt Mixtures ... •Proposed that aging at 135°C causes](https://reader030.vdocument.in/reader030/viewer/2022040607/5ebdcdc89d79be23090d6a15/html5/thumbnails/14.jpg)
Cracking Test Evaluation Project
![Page 15: Cracking Tests for Asphalt Mixtures and How to Mixture ...€¦ · Blankenship Asphalt Tech & Training Cracking Tests for Asphalt Mixtures ... •Proposed that aging at 135°C causes](https://reader030.vdocument.in/reader030/viewer/2022040607/5ebdcdc89d79be23090d6a15/html5/thumbnails/15.jpg)
We Need a Test(s) that Is…
15
• Sensitive properties of mix components
• Sensitive to mixture aging
• Repeatable and reproducible
• Easy to implement
o Less trimming/coring
o Small footprint
o Easy to run
• Practical, low cost
![Page 16: Cracking Tests for Asphalt Mixtures and How to Mixture ...€¦ · Blankenship Asphalt Tech & Training Cracking Tests for Asphalt Mixtures ... •Proposed that aging at 135°C causes](https://reader030.vdocument.in/reader030/viewer/2022040607/5ebdcdc89d79be23090d6a15/html5/thumbnails/16.jpg)
Review of Tests
16
1. AMPT Push/Pull Fatigue (S-VECD)
2. Indirect Tensile Strength (IDT)
3. 4-Point Bending Beam Fatigue
4. Dissipated Creep Strain Energy (DCSE)
5. Disk-Shaped Compact Tension [DC(T)]
6. Texas Overlay Test
7. Semi-Circular Bending (SCB)-ASTM
8. Semi-Circular Bending (SCB)-AASHTO (later version called iFit)
9. Indirect Tensile Asphalt Cracking Test (IDEAL-CT)at Intermediate Temperature
![Page 17: Cracking Tests for Asphalt Mixtures and How to Mixture ...€¦ · Blankenship Asphalt Tech & Training Cracking Tests for Asphalt Mixtures ... •Proposed that aging at 135°C causes](https://reader030.vdocument.in/reader030/viewer/2022040607/5ebdcdc89d79be23090d6a15/html5/thumbnails/17.jpg)
17
AMPT Push/Pull Fatigue (S-VECD)
![Page 18: Cracking Tests for Asphalt Mixtures and How to Mixture ...€¦ · Blankenship Asphalt Tech & Training Cracking Tests for Asphalt Mixtures ... •Proposed that aging at 135°C causes](https://reader030.vdocument.in/reader030/viewer/2022040607/5ebdcdc89d79be23090d6a15/html5/thumbnails/18.jpg)
AMPT Push/Pull Fatigue (S-VECD)
• Draft AASHTO standard by Richard Kim
• 18C / 23C
o Not recommended to run over 21C
• Various Strains
• Software builds curve based on three tests
![Page 19: Cracking Tests for Asphalt Mixtures and How to Mixture ...€¦ · Blankenship Asphalt Tech & Training Cracking Tests for Asphalt Mixtures ... •Proposed that aging at 135°C causes](https://reader030.vdocument.in/reader030/viewer/2022040607/5ebdcdc89d79be23090d6a15/html5/thumbnails/19.jpg)
AMPT Push/Pull Fatigue (S-VECD)
• Good test for design
• Not intended for 24-hr aged mixtures
![Page 20: Cracking Tests for Asphalt Mixtures and How to Mixture ...€¦ · Blankenship Asphalt Tech & Training Cracking Tests for Asphalt Mixtures ... •Proposed that aging at 135°C causes](https://reader030.vdocument.in/reader030/viewer/2022040607/5ebdcdc89d79be23090d6a15/html5/thumbnails/20.jpg)
20
Indirect Tensile Strength (IDT)
![Page 21: Cracking Tests for Asphalt Mixtures and How to Mixture ...€¦ · Blankenship Asphalt Tech & Training Cracking Tests for Asphalt Mixtures ... •Proposed that aging at 135°C causes](https://reader030.vdocument.in/reader030/viewer/2022040607/5ebdcdc89d79be23090d6a15/html5/thumbnails/21.jpg)
Indirect Tensile Strength (IDT)
• ASTM D 6931
• Related AASHTO T322
• 25.0C and 4.0C
• Rate of Movement: 12.5 and 50 mm/min
![Page 22: Cracking Tests for Asphalt Mixtures and How to Mixture ...€¦ · Blankenship Asphalt Tech & Training Cracking Tests for Asphalt Mixtures ... •Proposed that aging at 135°C causes](https://reader030.vdocument.in/reader030/viewer/2022040607/5ebdcdc89d79be23090d6a15/html5/thumbnails/22.jpg)
Indirect Tensile Strength (IDT)
Simplest test, but just says that mix
gets stiffer
![Page 23: Cracking Tests for Asphalt Mixtures and How to Mixture ...€¦ · Blankenship Asphalt Tech & Training Cracking Tests for Asphalt Mixtures ... •Proposed that aging at 135°C causes](https://reader030.vdocument.in/reader030/viewer/2022040607/5ebdcdc89d79be23090d6a15/html5/thumbnails/23.jpg)
Indirect Tensile Strength (IDT)
![Page 24: Cracking Tests for Asphalt Mixtures and How to Mixture ...€¦ · Blankenship Asphalt Tech & Training Cracking Tests for Asphalt Mixtures ... •Proposed that aging at 135°C causes](https://reader030.vdocument.in/reader030/viewer/2022040607/5ebdcdc89d79be23090d6a15/html5/thumbnails/24.jpg)
Indirect Tensile Strength (IDT)
So what can we learn? Confirms that we need correct
temperature/loading rate for cracking sensitivity. Peak load alone is not
the answer…but combine with time/distance FRACTURE ENERGY
![Page 25: Cracking Tests for Asphalt Mixtures and How to Mixture ...€¦ · Blankenship Asphalt Tech & Training Cracking Tests for Asphalt Mixtures ... •Proposed that aging at 135°C causes](https://reader030.vdocument.in/reader030/viewer/2022040607/5ebdcdc89d79be23090d6a15/html5/thumbnails/25.jpg)
26
4-Point Bending Beam Fatigue
![Page 26: Cracking Tests for Asphalt Mixtures and How to Mixture ...€¦ · Blankenship Asphalt Tech & Training Cracking Tests for Asphalt Mixtures ... •Proposed that aging at 135°C causes](https://reader030.vdocument.in/reader030/viewer/2022040607/5ebdcdc89d79be23090d6a15/html5/thumbnails/26.jpg)
4-Point Bending Beam Fatigue
• 4-point bending beam fatigue (1950’s / SHRP)
• AASHTO T321 & ASTM 7460
• Examined• 20.0C & 15.0C• Sine & haversine
waves
• Rate of Movement: 10Hz, various strains (strain rates)
• Ex: 300 ms = 0.16mm/0.1sec or 98mm/min
• 2 beams for average (per strain)
![Page 27: Cracking Tests for Asphalt Mixtures and How to Mixture ...€¦ · Blankenship Asphalt Tech & Training Cracking Tests for Asphalt Mixtures ... •Proposed that aging at 135°C causes](https://reader030.vdocument.in/reader030/viewer/2022040607/5ebdcdc89d79be23090d6a15/html5/thumbnails/27.jpg)
Beam Fatigue – 20C & sine
![Page 28: Cracking Tests for Asphalt Mixtures and How to Mixture ...€¦ · Blankenship Asphalt Tech & Training Cracking Tests for Asphalt Mixtures ... •Proposed that aging at 135°C causes](https://reader030.vdocument.in/reader030/viewer/2022040607/5ebdcdc89d79be23090d6a15/html5/thumbnails/28.jpg)
Beam Fatigue - 15C & sine
![Page 29: Cracking Tests for Asphalt Mixtures and How to Mixture ...€¦ · Blankenship Asphalt Tech & Training Cracking Tests for Asphalt Mixtures ... •Proposed that aging at 135°C causes](https://reader030.vdocument.in/reader030/viewer/2022040607/5ebdcdc89d79be23090d6a15/html5/thumbnails/29.jpg)
EXAMPLE: KY Density Study Findings with 24-hr Loose Mix Conditioning – M. Anderson
Beam fatigue device has been used to better understand
pavement cracking potential.
Alireza Zeinali, Phillip B. Blankenship, Kamyar C. Mahboub
![Page 30: Cracking Tests for Asphalt Mixtures and How to Mixture ...€¦ · Blankenship Asphalt Tech & Training Cracking Tests for Asphalt Mixtures ... •Proposed that aging at 135°C causes](https://reader030.vdocument.in/reader030/viewer/2022040607/5ebdcdc89d79be23090d6a15/html5/thumbnails/30.jpg)
32
Dissipated Creep Strain Energy (DCSE)
![Page 31: Cracking Tests for Asphalt Mixtures and How to Mixture ...€¦ · Blankenship Asphalt Tech & Training Cracking Tests for Asphalt Mixtures ... •Proposed that aging at 135°C causes](https://reader030.vdocument.in/reader030/viewer/2022040607/5ebdcdc89d79be23090d6a15/html5/thumbnails/31.jpg)
Dissipated Creep Strain Energy (DCSE)
• Draft standard by Rey Roque
• Uses IDT configuration
• Creep based on load & time
• 10C
• 3 samples for average
![Page 32: Cracking Tests for Asphalt Mixtures and How to Mixture ...€¦ · Blankenship Asphalt Tech & Training Cracking Tests for Asphalt Mixtures ... •Proposed that aging at 135°C causes](https://reader030.vdocument.in/reader030/viewer/2022040607/5ebdcdc89d79be23090d6a15/html5/thumbnails/32.jpg)
35
Disk-Shaped Compact Tension
[DC(T)]
![Page 33: Cracking Tests for Asphalt Mixtures and How to Mixture ...€¦ · Blankenship Asphalt Tech & Training Cracking Tests for Asphalt Mixtures ... •Proposed that aging at 135°C causes](https://reader030.vdocument.in/reader030/viewer/2022040607/5ebdcdc89d79be23090d6a15/html5/thumbnails/33.jpg)
Disk-Shaped Compact Tension [DC(T)]
• ASTM D 7313
• Run at +10C from critical low temp PG
• -12.0C
• Rate of Movement: 1 mm/min
• 3 samples for average
![Page 34: Cracking Tests for Asphalt Mixtures and How to Mixture ...€¦ · Blankenship Asphalt Tech & Training Cracking Tests for Asphalt Mixtures ... •Proposed that aging at 135°C causes](https://reader030.vdocument.in/reader030/viewer/2022040607/5ebdcdc89d79be23090d6a15/html5/thumbnails/34.jpg)
EXAMPLE: Pavement Preservation with Chip Seal
![Page 35: Cracking Tests for Asphalt Mixtures and How to Mixture ...€¦ · Blankenship Asphalt Tech & Training Cracking Tests for Asphalt Mixtures ... •Proposed that aging at 135°C causes](https://reader030.vdocument.in/reader030/viewer/2022040607/5ebdcdc89d79be23090d6a15/html5/thumbnails/35.jpg)
39
Texas Overlay Test
![Page 36: Cracking Tests for Asphalt Mixtures and How to Mixture ...€¦ · Blankenship Asphalt Tech & Training Cracking Tests for Asphalt Mixtures ... •Proposed that aging at 135°C causes](https://reader030.vdocument.in/reader030/viewer/2022040607/5ebdcdc89d79be23090d6a15/html5/thumbnails/36.jpg)
Texas Overlay Test
• Tx DOT Standard
• Tex-248-F
• 25C
• Rate of Movement: 0.6 mm/5 sec and returns (fatigue) or 7.2mm/min
• 0.1 Hz
• 6 samples for
![Page 37: Cracking Tests for Asphalt Mixtures and How to Mixture ...€¦ · Blankenship Asphalt Tech & Training Cracking Tests for Asphalt Mixtures ... •Proposed that aging at 135°C causes](https://reader030.vdocument.in/reader030/viewer/2022040607/5ebdcdc89d79be23090d6a15/html5/thumbnails/37.jpg)
Texas Overlay Test
Note: High error. Data is usually trimmed average.
![Page 38: Cracking Tests for Asphalt Mixtures and How to Mixture ...€¦ · Blankenship Asphalt Tech & Training Cracking Tests for Asphalt Mixtures ... •Proposed that aging at 135°C causes](https://reader030.vdocument.in/reader030/viewer/2022040607/5ebdcdc89d79be23090d6a15/html5/thumbnails/38.jpg)
42
Semi-Circular Bending (SCB)-
ASTM
![Page 39: Cracking Tests for Asphalt Mixtures and How to Mixture ...€¦ · Blankenship Asphalt Tech & Training Cracking Tests for Asphalt Mixtures ... •Proposed that aging at 135°C causes](https://reader030.vdocument.in/reader030/viewer/2022040607/5ebdcdc89d79be23090d6a15/html5/thumbnails/39.jpg)
Semi-Circular Bending (SCB)-ASTM
• ASTM standard by Louay Mohammad
• 25C
• Rate of Movement: 0.5 mm/min
![Page 40: Cracking Tests for Asphalt Mixtures and How to Mixture ...€¦ · Blankenship Asphalt Tech & Training Cracking Tests for Asphalt Mixtures ... •Proposed that aging at 135°C causes](https://reader030.vdocument.in/reader030/viewer/2022040607/5ebdcdc89d79be23090d6a15/html5/thumbnails/40.jpg)
Semi Circular Bend (SCB) Test Fracture mechanics
Temperature: 25 C
Half-circular Specimen
– Laboratory prepared
– Field core
– 150mm diameter X 57mm thickness
– simply-supported and loaded at mid-point
Notch controls path of crack propagation
– 25.4-, 31.8-, and 38.0-mm
Loading type
– Monotonic
– 0.5 mm/min
– To failure
Record Load and Vertical Deformation
Compute Critical Strain Energy: Jc
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
0.0 0.5 1.0 1.5 2.0 2.5
Lo
ad
(kN
)
Deflection (mm)
Peak Load
notch a1
U1
![Page 41: Cracking Tests for Asphalt Mixtures and How to Mixture ...€¦ · Blankenship Asphalt Tech & Training Cracking Tests for Asphalt Mixtures ... •Proposed that aging at 135°C causes](https://reader030.vdocument.in/reader030/viewer/2022040607/5ebdcdc89d79be23090d6a15/html5/thumbnails/41.jpg)
Semi-Circular Bend Test Results, 25°C
• Can have high error. Usually based on 6 samples
• Higher temps or lower PG yields lower energy
o This is opposite of what should happen
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
4-hr 24-hr
Jc, K
j/m2
Mixture Type
![Page 42: Cracking Tests for Asphalt Mixtures and How to Mixture ...€¦ · Blankenship Asphalt Tech & Training Cracking Tests for Asphalt Mixtures ... •Proposed that aging at 135°C causes](https://reader030.vdocument.in/reader030/viewer/2022040607/5ebdcdc89d79be23090d6a15/html5/thumbnails/42.jpg)
47
Semi-Circular Bending (SCB)-AASHTO (later
version called iFit)
![Page 43: Cracking Tests for Asphalt Mixtures and How to Mixture ...€¦ · Blankenship Asphalt Tech & Training Cracking Tests for Asphalt Mixtures ... •Proposed that aging at 135°C causes](https://reader030.vdocument.in/reader030/viewer/2022040607/5ebdcdc89d79be23090d6a15/html5/thumbnails/43.jpg)
What About iFit?Semi-Circular Bending (SCB)-AASHTO
• AASHTO TP-124 by Imad Al-Qadi
• 25C
• Rate of Movement: 50 mm/min
• Focus on latest standard on Flexibility Index (FI)
![Page 44: Cracking Tests for Asphalt Mixtures and How to Mixture ...€¦ · Blankenship Asphalt Tech & Training Cracking Tests for Asphalt Mixtures ... •Proposed that aging at 135°C causes](https://reader030.vdocument.in/reader030/viewer/2022040607/5ebdcdc89d79be23090d6a15/html5/thumbnails/44.jpg)
What about iFit?
From Research Report No. FHWA-ICT-15-017, “Testing Protocols to Ensure Performance of High Asphalt
Binder Replacement Mixes Using RAP and RAS” by Al-Qadi, et.al.
![Page 45: Cracking Tests for Asphalt Mixtures and How to Mixture ...€¦ · Blankenship Asphalt Tech & Training Cracking Tests for Asphalt Mixtures ... •Proposed that aging at 135°C causes](https://reader030.vdocument.in/reader030/viewer/2022040607/5ebdcdc89d79be23090d6a15/html5/thumbnails/45.jpg)
What about iFit?
• Showing much promise
• Current work on field mixes
• More work to come on longer aged mixes
![Page 46: Cracking Tests for Asphalt Mixtures and How to Mixture ...€¦ · Blankenship Asphalt Tech & Training Cracking Tests for Asphalt Mixtures ... •Proposed that aging at 135°C causes](https://reader030.vdocument.in/reader030/viewer/2022040607/5ebdcdc89d79be23090d6a15/html5/thumbnails/46.jpg)
51
Following slides from Texas A&M
Indirect Tensile Asphalt Cracking Test
(IDEAL-CT)at Intermediate
Temperature
![Page 47: Cracking Tests for Asphalt Mixtures and How to Mixture ...€¦ · Blankenship Asphalt Tech & Training Cracking Tests for Asphalt Mixtures ... •Proposed that aging at 135°C causes](https://reader030.vdocument.in/reader030/viewer/2022040607/5ebdcdc89d79be23090d6a15/html5/thumbnails/47.jpg)
Development of IDEAL-CT
IDEAL-CT concept
![Page 48: Cracking Tests for Asphalt Mixtures and How to Mixture ...€¦ · Blankenship Asphalt Tech & Training Cracking Tests for Asphalt Mixtures ... •Proposed that aging at 135°C causes](https://reader030.vdocument.in/reader030/viewer/2022040607/5ebdcdc89d79be23090d6a15/html5/thumbnails/48.jpg)
Development of IDEAL-CT
CTindex Equation
![Page 49: Cracking Tests for Asphalt Mixtures and How to Mixture ...€¦ · Blankenship Asphalt Tech & Training Cracking Tests for Asphalt Mixtures ... •Proposed that aging at 135°C causes](https://reader030.vdocument.in/reader030/viewer/2022040607/5ebdcdc89d79be23090d6a15/html5/thumbnails/49.jpg)
IDEAL-CT sensitivity
Sensitivity to RAP/RAS
![Page 50: Cracking Tests for Asphalt Mixtures and How to Mixture ...€¦ · Blankenship Asphalt Tech & Training Cracking Tests for Asphalt Mixtures ... •Proposed that aging at 135°C causes](https://reader030.vdocument.in/reader030/viewer/2022040607/5ebdcdc89d79be23090d6a15/html5/thumbnails/50.jpg)
IDEAL-CT sensitivity
Sensitivity to binder type
![Page 51: Cracking Tests for Asphalt Mixtures and How to Mixture ...€¦ · Blankenship Asphalt Tech & Training Cracking Tests for Asphalt Mixtures ... •Proposed that aging at 135°C causes](https://reader030.vdocument.in/reader030/viewer/2022040607/5ebdcdc89d79be23090d6a15/html5/thumbnails/51.jpg)
IDEAL-CT sensitivity
Sensitivity to binder content
![Page 52: Cracking Tests for Asphalt Mixtures and How to Mixture ...€¦ · Blankenship Asphalt Tech & Training Cracking Tests for Asphalt Mixtures ... •Proposed that aging at 135°C causes](https://reader030.vdocument.in/reader030/viewer/2022040607/5ebdcdc89d79be23090d6a15/html5/thumbnails/52.jpg)
Refer to NCHRP 9-57 for Further Info
![Page 53: Cracking Tests for Asphalt Mixtures and How to Mixture ...€¦ · Blankenship Asphalt Tech & Training Cracking Tests for Asphalt Mixtures ... •Proposed that aging at 135°C causes](https://reader030.vdocument.in/reader030/viewer/2022040607/5ebdcdc89d79be23090d6a15/html5/thumbnails/53.jpg)
How to Condition Mixtures
60
• Short-term (absorption)
o 2 to 4 hours on loose mix at 135°C
• Stir hourly
• Longer time needed for > 2% water absorption
![Page 54: Cracking Tests for Asphalt Mixtures and How to Mixture ...€¦ · Blankenship Asphalt Tech & Training Cracking Tests for Asphalt Mixtures ... •Proposed that aging at 135°C causes](https://reader030.vdocument.in/reader030/viewer/2022040607/5ebdcdc89d79be23090d6a15/html5/thumbnails/54.jpg)
How to Condition Mixtures
61
• Long-term (aging to simulate time in field)
o Currently three (3) options
• AASHTO R-30: 120 ± 0.5 hours at 85 ± 3°C on compacted sample
• UIUC/AI: 24 hours at 135°C on loose mix
• Proposed that aging at 135°C causes changes in the chemistry of the binder that are not realistic
• National Cooperative Highway Research Program (NCHRP) 09-54: Suggests 95°C as optimal temperature for aging loose mix. Time is adjusted based on climate conditions and pavement depth.
• One study cited 5 - 12 days corresponding to preliminary recommendations of NCHRP 09-54 study
![Page 55: Cracking Tests for Asphalt Mixtures and How to Mixture ...€¦ · Blankenship Asphalt Tech & Training Cracking Tests for Asphalt Mixtures ... •Proposed that aging at 135°C causes](https://reader030.vdocument.in/reader030/viewer/2022040607/5ebdcdc89d79be23090d6a15/html5/thumbnails/55.jpg)
Why 24 Hour Loose Mix Aging• Focus on aging of the top ~1-2 inches
• University of Illinois – study on in-place mixtures
o Andrew F. Braham, William G. Buttlar, Timothy R. Clyne
• AAPTP non-load associated cracking study
o Also found that 18hr loose mix 20hr PAV
• KY density study
![Page 56: Cracking Tests for Asphalt Mixtures and How to Mixture ...€¦ · Blankenship Asphalt Tech & Training Cracking Tests for Asphalt Mixtures ... •Proposed that aging at 135°C causes](https://reader030.vdocument.in/reader030/viewer/2022040607/5ebdcdc89d79be23090d6a15/html5/thumbnails/56.jpg)
Conclusions
• We need to condition mixtures to simulate proper field conditions at 7 to 10 years
o 95C aging or 24-hr loose mix aging @ 135
• All tests seem to recognize the conditioned mixtures except for the IDT strength
o Strength alone is not enough
• Need to accept tests for what they are and designed to do
• Adjust tests for climates
![Page 57: Cracking Tests for Asphalt Mixtures and How to Mixture ...€¦ · Blankenship Asphalt Tech & Training Cracking Tests for Asphalt Mixtures ... •Proposed that aging at 135°C causes](https://reader030.vdocument.in/reader030/viewer/2022040607/5ebdcdc89d79be23090d6a15/html5/thumbnails/57.jpg)
http://asphalttechnology.org/membership.html
Become an AAPT Member!
• Access to information and emerging technologies• Part of a technical community comprised of
individuals from all parts of the asphalt industry• Debate on important technical issues• North American-based organization with significant
international membership and focus• Association operates without organizational biases• Support the next generation of asphalt technologists
through a robust student scholarship program
![Page 58: Cracking Tests for Asphalt Mixtures and How to Mixture ...€¦ · Blankenship Asphalt Tech & Training Cracking Tests for Asphalt Mixtures ... •Proposed that aging at 135°C causes](https://reader030.vdocument.in/reader030/viewer/2022040607/5ebdcdc89d79be23090d6a15/html5/thumbnails/58.jpg)
Thank You
Phillip B. Blankenship, PEConsultant
Blankenship Asphalt Tech and Training, PLLC