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Fiber Reinforced Asphalt Pavements
54th ANNUAL IDAHO ASPHALT CONFERENCE
October 23, 2014Moscow, Idaho
Kamil E. Kaloush , Ph.D., P.E.
AgendaASU’s experience in testing and evaluation of FRAC
• Fiber Reinforced Asphalt Concrete (FRAC)
• Field projects constructed
• Process and production
• Laboratory tests
• On Going Research
3
Why do we use modifiers in HMA?• Mitigate both traffic and climateinduced pavement distresses– Rutting Resistance
• Stiffer asphalt binders
– Reduce Cracking• Eliminate or delay cracking
• Inhibit crack propagation
– Reduce Surface Wear: Raveling
4
Types of Modifiers• Polymers
Plastomers
Elastomers
• FillersGilsonite Mineral fillers
• Fibers1960’s Asbestos
polyester & polypropylene, glass, carbon, celluloseAramid (Kevlar)
over 31+ recycled waste fibers
Crumb / tire rubber
5
Why Fibers in HMA?• Additional tensile strength and fracture energy
• Reinforcing / load transfer element & minimize crackpropagation and severity
• Favors slight increase in optimum bitumen content
• Reduce drain down of bitumen in HMA
• Favorable cost
• Literature:– Increased dynamic modulus
– Better moisture susceptibility & freeze thaw resistance
– Rutting resistance
– Reduce, delay or eliminate of cracking
FHWAALFTests
Fibers in HMAMixtures
Tire Fibers
Coconut Fibers
Cellulose Fibers
(Chowdhary et al.)
(Passos, 2005).(FORTA®)
HuaxinChen et al(2009)
Tire Fibers Early Research in Arizona
The effect of polypropylene fibers on asphalt performance – Tapkin,ScienceDirect 2007
https://carpetrecovery.org/wp-content/uploads/2014/04/NyconG.pdf
Rheological properties of fiber reinforcedasphalt binders – Ye and Wu, IndianJournal of Engineering & MaterialsSciences, 2008
Scanning Electron Microscope(SEM):
Cellulose: flocculent materialwith porous and ribbon typesurface (strong absorption ofbinder)
Polyester and mineral fibers:round and smooth surface,much lower absorption.
FORTA® AR® FiberBlend of collated Polypropylene and Aramidfibers
FORTA® Fibers fibrillated
Physical Characteristics
Materials Polypropylene Aramid
Specific Gravity 0.91 1.45
Tensile Strength (MPa) 483 3000
Length (mm) 19 19
Acid/Alkali Resistance inert inert
DecompositionTemperature (°C) 157 >450
ASU Early Projects
• Boeing Mixture –Pilot Study
• City of Tempe –Evergreen Drive
Binder Mix Design Data Mix Type
Binder Type Design AC (%) Target Va (%) Gmm FORTA Boeing PHX D-1/2 PG 70-10 5.10 7 2.4605
Binder Mix Design Data Mix Type Binder Type Design AC (%) Target Va (%) Gmm
PHX C-3/4 Control PG 70-10 5.00 7 2.428 PHX C-3/4 1 lb/Ton PG 70-10 5.00 7 2.458 PHX C-3/4 2 lb/Ton PG 70-10 5.00 7 2.471
Evergreen Drive
Boeing
Laboratory Tests• Binder Tests• Triaxial Shear Strength• Dynamic Modulus• Permanent Deformation
– Repeated Load– Static Creep
• Beam and Axial Fatigue• Indirect Tensile Strength and Creep• Fracture and Crack Propagation
Polypropylene Modified Binder
Mix time and temperature:Time: 30 minTemperature: 329 and 365 F(165-185 C)
Conventional Tests
Superpave / SHRP Tests
Penetration AASHTO T49-93Softening Point AASHTO T53-92Rotational Viscosity AASHTO TP48
Dynamic Shear Rheometer (DSR): AASHTO PP1Bending Beam Rheometer(BBR): AASHTO TP1-98
Binder Tests
0.0
0.2
0.4
0.6
0.8
1.0
2.70 2.75 2.80 2.85 2.90 2.95
Log (Temp, oRankine)
Log
(Log
vis
cosi
ty, c
P)
(41) (103) (171) (248) (335) (432)(deg F)
0.0
0.2
0.4
0.6
0.8
1.0
2.70 2.75 2.80 2.85 2.90 2.95
Log (Temp, oRankine)
Log
(Log
vis
cosi
ty, c
P)
(41) (103) (171) (248) (335) (432)(deg F)
Pen59, 77oF
Soft. Point 139oF
Brookfield Viscosity 200-350oF
Viscosity – Temperature
BINDER TEST RESULTS
Laboratory MixingProcedure
Field Laboratory Mixes
Field Laboratory Mixes
Visual Observation
DYNAMIC COMPLEX MODULUS (E*)E* = Dynamic Complex Modulus = o / o
o = peak dynamic stress amplitude (kPa / psi)
o = peak recoverable strain (mm/mm or in/in)
= phase lag or angle (degrees) = VISCOELASTIC PROPERTY
Time
Stre
ss-S
train
o o
o sin( t – )
o sin( t)
E* TESTRESULTS
747,179
479,964
1,097,269
242,350133,365148,180
0
200,000
400,000
600,000
800,000
1,000,000
1,200,000
Salt River 3/4" PG70-10 Salt River 3/4" PG64-22 Fiber-Reinforced
E*,
psi
100 F 130 F
Evergreen
Boeing
4,027,411
5,132,366
1,500,000818,000
466,000294,000
0
1,000,000
2,000,000
3,000,000
4,000,000
5,000,000
6,000,000
7,000,000
Control 1 lb/Ton
E*, p
si
40 F 100 F 130 F
Repeated Load PermanentDeformation Tests
Secondary
Primary
Tertiary
FN Defines N/Time WhenShear Deformation Begins
Repeated Load Permanent Deformation Test(Flow Number) Fiber Reinforced Asphalt
0.0
0.4
0.8
1.2
1.6
2.0
2.4
0 20000 40000 60000 80000 100000Cycles, N
Acc
umul
ated
Str
ain
(%) WesTrack Section 19
Fiber-Reinforced Asphalt
(a)
Boeing
Flow Number Evergreen Dr.
Fatigue Test Results
Nf = 6.16E-15. -5.15
R2 = 0.89
Nf = 1.54E-16. -5.42
R2 = 0.95Nf = 2.13E-13 -4.67
R2 = 0.87
10
100
1000
1000 10000 100000 1000000 10000000
Number of Cycles (N)
Stra
in L
evel
()
Conventional 3/4" MixPG 70-10
Fiber-Reinforced Mix
Conventional 3/4" Mix PG 64-22
Fatigue Test Results
Flexural Strength and Post Peak Energy
Force vs Deflection-FEC20
0
50
100
150
200
250
300
0.000 0.050 0.100 0.150 0.200 0.250 0.300
Deflection, in
Forc
e, L
bs
Comparative Plot – Cyclic Load
0
50
100
150
200
250
0.000 0.050 0.100 0.150 0.200 0.250 0.300
Deflection (in)
Forc
e (lb
)
Control1 lb/Ton2 lb/Ton
Peak =176 lb Peak = 170 lb
Peak = 111 lb
Indirect Tension Tests
• Disk shape specimen (150 x 38 mm) withvertical and horizontal LVDTs on both sides
• The tensile creep– Three temp: 0, 10, and 20oC– Static load along the diametral axis of a
specimen– Deformations used to calculate tensile creep
compliance as a function of time
• The tensile strength– Determined immediately after the tensile
creep test– Constant rate of vertical deformation to
failureIndirect Tensile Tests Loading Frame and Specimen with LVDTs
Tensile Strength Evergreen
371
408410
610
571
468
598
579
467
300
350
400
450
500
550
600
650
700
0 10 20 30 40 50 60
TEMPERATURE (oF)
TE
NSI
LE
ST
RE
NG
TH
(ps
FEControl FE1lb-Ton FE2lb-Ton
Total Fracture EnergyTOTAL FRACTURE ENERGY OF FORTA EVERGREEN MIXES
279.3
163.2113.0
198.0
284.5430.4
206.7294.3
550.6
0
100
200
300
400
500
600
700
0 10 20 30 40 50 60
TEMPERATURE (oF)
TO
TA
L F
RA
CT
UR
E E
NE
RG
Y (l
bs-p
s
FEControl FE1lb-Ton FE2lb-Ton
VERTICAL DEFORMATION
LOA
D (l
bs)
Fracture EnergyArea under curve
Comparison of Indirect TensileStrength at 5 Temperatures
00.5
11.5
22.5
33.5
44.5
-10 0 10 21.2 37.8
Indi
rect
Ten
sile
Stre
ngth
, N/m
m2
Temperature, °C
IDT Comparison
Control 1 lb/ton 2 lb/ton
FRACTURE AND CRACK GROWTHMODELC* LINE INTEGRAL
• C* Line Integral–analog of the Jintegral where strains anddisplacement replaced by their rates(time dependent materials)
• Defined as the difference of 2identically loaded bodies havingincrementally differing crack lengths
dU*=Change in energy rate for a load P and a crack extension dCB=thickness
dCdU
BC *1*
C* MULTIPLE SPECIMENS METHOD
• Specimenssubjected to different constant displacementrates
• Load and crack length measured as a function of time
T (time)
P (L
oad)
a (c
rack
leng
th)
Step 1
a
P
(displacement rate)
P (L
oad)
Step 2
a1
a2
a3
a1>a2>a3
Load vs displacement rate for fixed crack lengthArea under the curve= rate of work done U* per unit of crack plane thickness
a (Crack Length)
U* (
Ene
rgy
Rat
e)
Step 3
1
2
3
1< 2< 3
Crack growth rate are plotted versus crack length
(displacement rate)
C* L
ine
Inte
gral
Step 4
Area under the curve ( Step 3) is plotted against crack lengthSlope of curve is C*
Crack growth rate is plotted as a function of C*The higher the slope the more resistant the material
C* L
ine
Inte
gral
Step 5
(Crack Growth rate)
C* LINE INTEGRAL Literature Results
Abdulshafi and Kaloush (1988)
C* Fracture Test
Develop test geometry, protocol, temperature andloading rate dependency, FE analysis and predictivemodels
(Jeff Stempihar, PhD 2013)
C* LINE INTEGRAL
ACTUAL TEST PERFORMED20 minutes
C* Fracture Test
Post Test Failure
10/26/2014
What is the field telling us?Boeing – Mesa, AZ
infield placed in 20082010, broken pipe caused a sink 2.5’ W x 8’ L x 2.5” DOnly (1) 10” crack found
10/26/2014
Field MaintenanceAsphalt saw-cut & removed in 2 pieces 3’W x 8’L x 2”Thick
One center anchor on 560lbs slabRemoved in one piece!
Evergreen DriveDecember 2013
Fibers Extraction
xylene, toluene and trichloroethylene
Centrifuge Procedure
Fibers Recovery
Microscopic Observations ofRecovered Fibers
Summary of Laboratory Tests (Fibers Benefits)– The viscosity temperature susceptibility relationshipshowed positive and desirable modification process.
– Higher Dynamic Modulus E* values compared to theconventional mixtures.
– Gradual accumulation in permanent strain and highertertiary flow values => desirable properties to resist rutting.
– Higher fatigue life and fracture energy– Higher crack propagation resistance as represented by theC* Fracture Test.
– Fiber extraction Process• Good estimate of actual fiber content• Quality Control / Quality Assurance
USE of Data in the MEPDG (PavementME)
Extrapolated Layer Coefficient of Fiber ReinforcedAsphalt Concrete Mixture
600,000
0.44
630,000
Fiber Reinforced Mixture
Typical Dense Graded Mixture
0.53
Laboratory Evaluation
Mix Property JACMixture
SHRMixture
(Control)
SieveSize (US)
SieveSize (SI)
JACMixture
% Passing
SHRMixture
% Passing
FAA P-402 Control Points
Gradation Open Open 1" 25.4 - - -
Binder PG 64-34 PG 64-34 3/4" 19 100 100 100
Asphalt Content 5.70% 5.60% 1/2" 12.7 82 85 70-90
Laboratory Target Air Voids
13,15%* 15,17%* 3/8" 9.5 57 52 40-65
Gmm 2.416 2.540 No. 4 4.76 22 19 15-25
Hydrated Lime (%) 0.75% - No. 8 2.38 12 13 8-15
Fiber Reinforcement 1 lb/ton (0.5 kg/MT) None No. 30 0.6 6 7 5-9
Mixing/Compaction Temp, F ( C)
325/300 (163/149)
325/300 (163/149) No. 200 0.074 2 2.5 1-5
*Air voids for cylinder and beam samples, respectively (Corelok Method)
Jackson Hole Airport •Temperature changes from: -40oF to 41o F (winter) & up to 104oF in the summer•Elevation requires higher approach speeds•Short runway length•Accommodates planes such as the 757 and A320•Snow plowing caused raveling in existing pavement
Raveling Test
Location Replicate Wi Wf % Loss Average CV
Jackson HoleAirport
1 986.8 959.6 2.8%
2.6% 16.9%2 970.1 940.2 3.1%
3 967.6 945.1 2.3%
4 1031.5 1009.7 2.1%
Control
1 987.8 953.4 3.5%
3.7% 33.3%2 998.9 971.9 2.7%
3 963.5 910.9 5.5%
4 999.3 968.4 3.1%
•Cantabro Test •LA abrasion machine without steel balls•Mashall specimen size•Test temperature = 25 C
•Recommend a lower test temperature forsoft binders
CO2 EQUIVALENT EMMISSION COMPARISON
Service life (Y)
Total kg Annual CO2 Eq. /km runway (lb/mi runway) % Change
10 128279 (455,703) 100.0% 15 85519 (303,801) 33.3%
20* 64139 (227,850) 0.0% 25 51312 (182,283) -20.0% 30 42760 (151,902) -33.3%
The transport distance was assumed to be 25 km (15.5 miles), the density ofasphalt concrete was taken as 2275 kg/m3 (142 lb/ft3) and a runway width of 45.7 m(150 feet). The use of FRAC as the FAA P-401 surface course can result in a 33%decrease in total kg of annual CO2 equivalent per km of runway. This is based on theassumption that the dynamic modulus increases by 50% to 300,000 psi (1,723) forFRAC and is also limited by the current FAA design procedures.
* Standard FAA design life
ItemJackson Hole Airport Sheridan County Airport
Unit $/unit Total Cost Unit $/unitTotal Cost
P-402 Porous Friction Course, tons 8530 48.5 $413,705 5800 58.6 $339,880
PG 64-34 Modified Binder, tons 640 1000 $640,000 520 890 $462,800
Total Cost of HMA Mixture$1,053,70
5 $802,680Cost per Ton of HMA Mixture $124 $138
ItemJackson Hole Airport Sheridan County Airport
Unit $/unit Total Cost Unit $/unitTotal Cost
P-402 Porous Friction Course, tons 8530 50 $426,500 5800 60.4 $350,320
PG 64-34 Modified Binder, tons 640 1000 $640,000 520 890 $462,800Fiber Reinforcement Additive,
lbs 8530 7 $59,710 5800 8.35 $48,430
Total Cost of FRAC Mixture$1,126,21
0 $861,550Cost Per Ton of FRAC Mixture $132 $149
Cost Comparison
$0
$50,000
$100,000
$150,000
$200,000
$250,000
$300,000
4 6 8 10 12 14 16
EquivalentUniform
Ann
ualCost
Service Life (Years)
Jackson Hole
Jackson Hole with Fibers
Sheridan Co
Sheridan Co with Fibers
Cost Comparison
Project in ColumbiaAutopistas del Café
Downhill Curves (Location: Pereira)
• Downhill curve with high trafficvolume
• Raveling problems occur within 2month and yearly repairs whererequired (2009, 2010 & 2011);
• In January 2013, FORTA FI wasused with a dense HMA (“MDC2”) and a conventional 60 70binder;– Work done on 2 curves: milled
5cm and repaved with 5cm;– 16 month later, both curves are
in excellent condition;– No cracks, no raveling
Direccióndeltráfico
Bus stop(Medellín)
• Bus stop on a downhillalongside Parque VillaHermosa;
• Severe rutting within 2years; (May 2013)
• Work done: milling of15cm and paving a7.5cm base MSC 1 and a7.5 cm surface course ofMDC 2 with FORTA FI;
• 1 Year later road has norutting
Devimed PeajeDeviMed highway (Medellin to Bogota): already paved more than 50km x 9m wide by 6 cm average.
Toll booth, Peaje Guarne is one of the most congested roads out of Medellin. Problems: reflective cracking
Paved with FORTA-FI, 7 cm thick by PAVIMENTAR
Other on going research