1
Asphalt Cements
- New Superpave
Performance Graded
Specification
2
PG Specifications
• Fundamental properties related to
pavement performance
• Environmental factors
• In-service & construction temperatures
• Short and long term aging
3
PG Specifications
• Based on rheological testing
– Rheology: study of flow and deformation
• Asphalt cement is a viscoelastic material
• Behavior depends on:
– Temperature
– Time of loading
– Aging (properties change with time)
4
High Temperature Behavior
• High in-service temperature
– Desert climates
– Summer temperatures
• Sustained loads
– Slow moving trucks
– Intersections
Viscous Liquid
5
Pavement Behavior
(Warm Temperatures)
• Permanent deformation (rutting)
• Mixture is plastic
• Depends on asphalt source, additives,
and aggregate properties
6
Permanent Deformation
Function of warm weather and traffic
Courtesy of FHWA
7
Low Temperature Behavior
• Low Temperature
– Cold climates
– Winter
• Rapid Loads
– Fast moving trucks
Elastic Solid
s = t E
Hooke’s Law
8
Pavement Behavior
(Low Temperatures)
• Thermal cracks
– Stress generated by contraction due to
drop in temperature
– Crack forms when thermal stresses
exceed ability of material to relieve
stress through deformation
• Material is brittle
• Depends on source of asphalt and
aggregate properties
9
Thermal Cracking
Courtesy of FHWA
10
Aging
• Asphalt reacts with oxygen
– “oxidative” or “age hardening”
• Short term
– Volatilization of specific components
– During construction process
• Long term
– Over life of pavement (in-service)
11
Superpave Asphalt Binder Specification
The grading system is based on Climate
PG 64 - 22
Performance
Grade
Average 7-day max
pavement temperature
Min pavement
temperature
12
Pavement Temperatures are Calculated
• Calculated by Superpave software
• High temperature
– 20 mm below the surface of mixture
• Low temperature
– at surface of mixture
Pave temp = f (air temp, depth, latitude)
13
RV DSR BBR
Construction
Tests Used in PG Specifications
14
Concentric Cylinder
Concentric Cylinder Rheometers
t Rq = Mi
2 p Ri2 L
g =
W R
Ro - Ri
15
Rotational Viscometer
(Brookfield)
Inner Cylinder
Torque Motor
Thermosel
Environmental
Chamber
Digital Temperature
Controller
16
RV
DSR
BBR
Original Properties, Rutting, and Fatigue
17
Dynamic Shear Rheometer (DSR)
• Parallel Plate Shear flow varies with
gap height and radius
Non-homogeneous flow
gR =
R Q
h
tR =
2 M
p R3
18 1 cycle
Time A
A
B
C
C
A
B
Fixed Plate
Oscillating Plate
Test operates at 10 rad/sec
or 1.59 Hz
360o = 2 p radians per circle
1 rad = 57.3o
19
Elastic Viscous
Time A
A
B
C
Strain
Strain in-phase
d = 0o
Strain out-of-phase
d = 90o
20
Viscous Modulus, G”
Storage Modulus, G’
Complex Modulus, G*
d
Complex Modulus is the vector sum of the
storage and viscous modulus
21
DSR Equipment DSR
Equipment Computer Control
and Data
Acquisition
22
Area for
Liquid Bath
Motor
Parallel Plates
with Sample
23
25 mm Plate with Sample
24
RV
DSR
BBR
Rutting
25
Permanent Deformation
Addressed by:
G*/sin d on unaged binder > 1.00 kPa
G*/sin d on RTFO aged binder > 2.20 kPa
For the early part
of the service life
26
Short Term Binder Aging
• Rolling Thin Film Oven
– Simulates aging from hot mixing and construction
27
Inside of RTFO
Fan
Air Line
Rotating
Bottle
Carriage
28
Bottles Before and After Testing
Opening in
Bottle
29
Testing
• Calculate mass loss after RTFO
• Determine G*/sin d for RTFO aged material at
same test temp. used for original asphalt
cement
Mass loss, % =
Original mass - Aged mass
Original mass
x 100
30
Question: Why a minimum G*/sin d to
address rutting
Answer: We want a stiff, elastic binder to
contribute to mix rutting resistance
How: By increasing G* or decreasing d
Permanent Deformation
31
RV
DSR
BBR
Fatigue
32
Fatigue Cracking
Function of repeated traffic loads over time
(in wheel paths)
33
Testing
• Aged binder
– Since long term performance problem,
include:
• Short term aging
• Long term aging
• Determine DSR parameters using 8 mm
plate and intermediate test temperature
34
Pressure Aging Vessel
(Long Term Aging)
• Simulates aging of an asphalt binder
for 7 to 10 years
• 50 gram sample is aged for 20 hours
• Pressure of 2,070 kPa (300 psi)
• At 90, 100 or 110 C
35
Bottom of
pressure aging
vessel
Rack of individual pans
(50g of asphalt / pan)
Pressure Aging Vessel
Vessel Lid Components
36
Pressure Aging Vessel
Courtesy of FHWA
37
Fatigue Cracking
• G* (sin d) on RTFO and PAV aged binder
• The parameter addresses the later part of
the fatigue life
• Value must be < 5000 kPa
38
Fatigue Cracking
• Question: Why a maximum G* sin d to
address fatigue?
Answer: We want a soft elastic binder (to
sustain many loads without cracking)
How: By decreasing G* or decreasing d
39
RV DSR
BBR
Thermal
Cracking
40
Bending Beam Rheometer
Air Bearing
Load Cell
Deflection Transducer
Fluid Bath
Computer
41
Bending Beam Rheometer Sample
42
Bending Beam Rheometer Equipment
Cooling
System
Fluid Bath Loading
Ram
43
Bending Beam Rheometer
• S(t) = P L3
4 b h3 d (t)
Where:
S(t) = creep stiffness (M Pa) at time, t
P = applied constant load, N
L = distance between beam supports (102 mm)
b = beam width, 12.5 mm
h = beam thickness, 6.25 mm
d(t) = deflection (mm) at time, t
44
Bending Beam Rheometer
• Evaluates low temperature stiffness
properties
– Creep stiffness
– Slope of response (called m-value)
8 15 30 60 120 240
Log Creep
Stiffness, S(t)
Log Loading Time, t (sec)
45
Is Stiffness Enough?
• No. Need to assess strain needed to
break specimen.
– Thermal cracking occurs when strain is
too great
• Direct tension test
– Currently (1998) in specification
• New equipment is now available
46
Direct Tension Test
D Le
D L
Load
Stress = s = P / A
Strain ef
sf
47
FHWA
Direct Tension Test
Courtesy of FHWA
48
Direct Tension Test
Courtesy of FHWA
49
Summary
Fatigue
Cracking Rutting
RTFO
Short Term Aging No aging
Construction
[RV] [DSR]
Low Temp
Cracking
[BBR]
[DTT]
PAV
Long Term Aging
Superpave Binder
Purchase
Specification
Superpave Asphalt Binder
Specification
The grading system is based on Climate
PG 64 - 22
Performance
Grade
Average 7-day max
pavement temperature
Min pavement
temperature
PG 46 PG 52 PG 58 PG 64 PG 70 PG 76 PG 82
(Rotational Viscosity) RV
90 90 100 100 100 (110) 100 (110) 110 (110)
(Flash Point) FP
46 52 58 64 70 76 82
46 52 58 64 70 76 82
(ROLLING THIN FILM OVEN) RTFO Mass Loss < 1.00 %
(Direct Tension) DT
(Bending Beam Rheometer) BBR Physical Hardening
2
8
-34 -40 -46 -10 -16 -22 -28 -34 -40 -46 -16 -22 -28 -34 -40 -10 -16 -22 -28 -34 -40 -10 -16 -22 -28 -34 -40 -10 -16 -22 -28 -34
-10 -16 -22 -28 -34
Avg 7-day Max, oC
1-day Min, oC
(PRESSURE AGING VESSEL) PAV
ORIGINAL
> 1.00 kPa
< 5000 kPa
> 2.20 kPa
S < 300 MPa m > 0.300
Report Value
> 1.00 %
20 Hours, 2.07 MPa
10 7 4 25 22 19 16 13 10 7 25 22 19 16 13 31 28 25 22 19 16 34 31 28 25 22 19 37 34 31 28 25 40 37 34 31
(Dynamic Shear Rheometer) DSR G* sin d
( Bending Beam Rheometer) BBR “S” Stiffness & “m”- value
-24 -30 -36 0 -6 -12 -18 -24 -30 -36 -6 -12 -18 -24 -30 0 -6 -12 -18 -24 -30 0 -6 -12 -18 -24 -30 0 -6 -12 -18 -24
0 -6 -12 -18 -24
-24 -30 -36 0 -6 -12 -18 -24 -30 -36 -6 -12 -18 -24 -30 0 -6 -12 -18 -24 -30 0 -6 -12 -18 -24 -30 0 -6 -12 -18 -
24 0 -6 -12 -18 -24
Performance Grades
(Dynamic Shear Rheometer) DSR G*/sin d
(Dynamic Shear Rheometer) DSR G*/sin d
< 3 Pa.s @ 135 oC
> 230 oC
CEC
PG 46 PG 52 PG 58 PG 64 PG 70 PG 76 PG 82
(Rotational Viscosity) RV
90 90 100 100 100 (110) 100 (110) 110 (110)
(Flash Point) FP
46 52 58 64 70 76 82
46 52 58 64 70 76 82
(ROLLING THIN FILM OVEN) RTFO Mass Loss < 1.00 %
(Direct Tension) DT
(Bending Beam Rheometer) BBR Physical Hardening
2
8
-34 -40 -46 -10 -16 -22 -28 -34 -40 -46 -16 -22 -28 -34 -40 -10 -16 -22 -28 -34 -40 -10 -16 -22 -28 -34 -40 -10 -16 -22 -28 -34
-10 -16 -22 -28 -34
Avg 7-day Max, oC
1-day Min, oC
(PRESSURE AGING VESSEL) PAV
ORIGINAL
< 5000 kPa
> 2.20 kPa
S < 300 MPa m > 0.300
Report Value
> 1.00 %
20 Hours, 2.07 MPa
10 7 4 25 22 19 16 13 10 7 25 22 19 16 13 31 28 25 22 19 16 34 31 28 25 22 19 37 34 31 28 25 40 37 34 31
(Dynamic Shear Rheometer) DSR G* sin d
( Bending Beam Rheometer) BBR “S” Stiffness & “m”- value
-24 -30 -36 0 -6 -12 -18 -24 -30 -36 -6 -12 -18 -24 -30 0 -6 -12 -18 -24 -30 0 -6 -12 -18 -24 -30 0 -6 -12 -18 -24
0 -6 -12 -18 -24
-24 -30 -36 0 -6 -12 -18 -24 -30 -36 -6 -12 -18 -24 -30 0 -6 -12 -18 -24 -30 0 -6 -12 -18 -24 -30 0 -6 -12 -18 -
24 0 -6 -12 -18 -24
How the PG Spec Works
(Dynamic Shear Rheometer) DSR G*/sin d
(Dynamic Shear Rheometer) DSR G*/sin d
< 3 Pa.s @ 135 oC
> 230 oC
CEC
58 64
Test Temperature
Changes
Spec Requirement
Remains Constant
> 1.00 kPa
PG 46 PG 52 PG 58 PG 64 PG 70 PG 76 PG 82
(Rotational Viscosity) RV
90 90 100 100 100 (110) 100 (110) 110 (110)
(Flash Point) FP
46 52 58 64 70 76 82
46 52 58 64 70 76 82
(ROLLING THIN FILM OVEN) RTFO Mass Loss < 1.00 %
(Direct Tension) DT
(Bending Beam Rheometer) BBR Physical Hardening
2
8
-34 -40 -46 -10 -16 -22 -28 -34 -40 -46 -16 -22 -28 -34 -40 -10 -16 -22 -28 -34 -40 -10 -16 -22 -28 -34 -40 -10 -16 -22 -28 -34
-10 -16 -22 -28 -34
Avg 7-day Max, oC
1-day Min, oC
(PRESSURE AGING VESSEL) PAV
ORIGINAL
< 5000 kPa
S < 300 MPa m > 0.300
Report Value
> 1.00 %
20 Hours, 2.07 MPa
10 7 4 25 22 19 16 13 10 7 25 22 19 16 13 31 28 25 22 19 16 34 31 28 25 22 19 37 34 31 28 25 40 37 34 31
(Dynamic Shear Rheometer) DSR G* sin d
( Bending Beam Rheometer) BBR “S” Stiffness & “m”- value
-24 -30 -36 0 -6 -12 -18 -24 -30 -36 -6 -12 -18 -24 -30 0 -6 -12 -18 -24 -30 0 -6 -12 -18 -24 -30 0 -6 -12 -18 -24
0 -6 -12 -18 -24
-24 -30 -36 0 -6 -12 -18 -24 -30 -36 -6 -12 -18 -24 -30 0 -6 -12 -18 -24 -30 0 -6 -12 -18 -24 -30 0 -6 -12 -18 -
24 0 -6 -12 -18 -24
Permanent Deformation
(Dynamic Shear Rheometer) DSR G*/sin d
(Dynamic Shear Rheometer) DSR G*/sin d
< 3 Pa.s @ 135 oC
> 230 oC
CEC
> 1.00 kPa
> 2.20 kPa •Unaged
•RTFO Aged
Permanent Deformation
• Addressed by high temp stiffness
– G*/sin d on unaged binder > 1.00 kPa
– G*/sin d on RTFO aged binder > 2.20 kPa
> Early part of
pavement
service life
Heavy Trucks
PG 46 PG 52 PG 58 PG 64 PG 70 PG 76 PG 82
(Rotational Viscosity) RV
90 90 100 100 100 (110) 100 (110) 110 (110)
(Flash Point) FP
46 52 58 64 70 76 82
46 52 58 64 70 76 82
(ROLLING THIN FILM OVEN) RTFO Mass Loss < 1.00 %
(Direct Tension) DT
(Bending Beam Rheometer) BBR Physical Hardening
2
8
-34 -40 -46 -10 -16 -22 -28 -34 -40 -46 -16 -22 -28 -34 -40 -10 -16 -22 -28 -34 -40 -10 -16 -22 -28 -34 -40 -10 -16 -22 -28 -34
-10 -16 -22 -28 -34
Avg 7-day Max, oC
1-day Min, oC
(PRESSURE AGING VESSEL) PAV
ORIGINAL
> 1.00 kPa
> 2.20 kPa
S < 300 MPa m > 0.300
Report Value
> 1.00 %
20 Hours, 2.07 MPa
10 7 4 25 22 19 16 13 10 7 25 22 19 16 13 31 28 25 22 19 16 34 31 28 25 22 19 37 34 31 28 25 40 37 34 31
(Dynamic Shear Rheometer) DSR G* sin d
( Bending Beam Rheometer) BBR “S” Stiffness & “m”- value
-24 -30 -36 0 -6 -12 -18 -24 -30 -36 -6 -12 -18 -24 -30 0 -6 -12 -18 -24 -30 0 -6 -12 -18 -24 -30 0 -6 -12 -18 -24
0 -6 -12 -18 -24
-24 -30 -36 0 -6 -12 -18 -24 -30 -36 -6 -12 -18 -24 -30 0 -6 -12 -18 -24 -30 0 -6 -12 -18 -24 -30 0 -6 -12 -18 -
24 0 -6 -12 -18 -24
Fatigue Cracking
(Dynamic Shear Rheometer) DSR G*/sin d
(Dynamic Shear Rheometer) DSR G*/sin d
< 3 Pa.s @ 135 oC
> 230 oC
CEC
< 5000 kPa
PAV Aged
Fatigue Cracking
• Addressed by intermediate
temperature stiffness
–G*sin d on RTFO & PAV
aged binder < 5000 kPa
> Later part of
pavement service life
PG 46 PG 52 PG 58 PG 64 PG 70 PG 76 PG 82
(Rotational Viscosity) RV
90 90 100 100 100 (110) 100 (110) 110 (110)
(Flash Point) FP
46 52 58 64 70 76 82
46 52 58 64 70 76 82
(ROLLING THIN FILM OVEN) RTFO Mass Loss < 1.00 %
(Direct Tension) DT
(Bending Beam Rheometer) BBR Physical Hardening
2
8
-34 -40 -46 -10 -16 -22 -28 -34 -40 -46 -16 -22 -28 -34 -40 -10 -16 -22 -28 -34 -40 -10 -16 -22 -28 -34 -40 -10 -16 -22 -28 -34
-10 -16 -22 -28 -34
Avg 7-day Max, oC
1-day Min, oC
(PRESSURE AGING VESSEL) PAV
ORIGINAL
> 1.00 kPa
< 5000 kPa
> 2.20 kPa
20 Hours, 2.07 MPa
10 7 4 25 22 19 16 13 10 7 25 22 19 16 13 31 28 25 22 19 16 34 31 28 25 22 19 37 34 31 28 25 40 37 34 31
(Dynamic Shear Rheometer) DSR G* sin d
( Bending Beam Rheometer) BBR “S” Stiffness & “m”- value
-24 -30 -36 0 -6 -12 -18 -24 -30 -36 -6 -12 -18 -24 -30 0 -6 -12 -18 -24 -30 0 -6 -12 -18 -24 -30 0 -6 -12 -18 -24
0 -6 -12 -18 -24
-24 -30 -36 0 -6 -12 -18 -24 -30 -36 -6 -12 -18 -24 -30 0 -6 -12 -18 -24 -30 0 -6 -12 -18 -24 -30 0 -6 -12 -18 -
24 0 -6 -12 -18 -24
Low Temperature Cracking
(Dynamic Shear Rheometer) DSR G*/sin d
(Dynamic Shear Rheometer) DSR G*/sin d
< 3 Pa.s @ 135 oC
> 230 oC
CEC
S < 300 MPa m > 0.300
Report Value
> 1.00 %
PAV Aged
PG 46 PG 52 PG 58 PG 64 PG 70 PG 76 PG 82
(Rotational Viscosity) RV
90 90 100 100 100 (110) 100 (110) 110 (110)
(Flash Point) FP
46 52 58 64 70 76 82
46 52 58 64 70 76 82
(ROLLING THIN FILM OVEN) RTFO Mass Loss < 1.00 %
(Direct Tension) DT
(Bending Beam Rheometer) BBR Physical Hardening
2
8
-34 -40 -46 -10 -16 -22 -28 -34 -40 -46 -16 -22 -28 -34 -40 -10 -16 -22 -28 -34 -40 -10 -16 -22 -28 -34 -40 -10 -16 -22 -28 -34
-10 -16 -22 -28 -34
Avg 7-day Max, oC
1-day Min, oC
(PRESSURE AGING VESSEL) PAV
ORIGINAL
> 1.00 kPa
< 5000 kPa
> 2.20 kPa
20 Hours, 2.07 MPa
10 7 4 25 22 19 16 13 10 7 25 22 19 16 13 31 28 25 22 19 16 34 31 28 25 22 19 37 34 31 28 25 40 37 34 31
(Dynamic Shear Rheometer) DSR G* sin d
( Bending Beam Rheometer) BBR “S” Stiffness & “m”- value
-24 -30 -36 0 -6 -12 -18 -24 -30 -36 -6 -12 -18 -24 -30 0 -6 -12 -18 -24 -30 0 -6 -12 -18 -24 -30 0 -6 -12 -18 -24
0 -6 -12 -18 -24
-24 -30 -36 0 -6 -12 -18 -24 -30 -36 -6 -12 -18 -24 -30 0 -6 -12 -18 -24 -30 0 -6 -12 -18 -24 -30 0 -6 -12 -18 -
24 0 -6 -12 -18 -24
Low Temperature Cracking
(Dynamic Shear Rheometer) DSR G*/sin d
(Dynamic Shear Rheometer) DSR G*/sin d
< 3 Pa.s @ 135 oC
> 230 oC
CEC
S < 300 MPa m > 0.300
Report Value
> 1.00 %
PAV Aged
PG 46 PG 52 PG 58 PG 64 PG 70 PG 76 PG 82
(Rotational Viscosity) RV
90 90 100 100 100 (110) 100 (110) 110 (110)
(Flash Point) FP
46 52 58 64 70 76 82
46 52 58 64 70 76 82
(ROLLING THIN FILM OVEN) RTFO Mass Loss < 1.00 %
(Direct Tension) DT
(Bending Beam Rheometer) BBR Physical Hardening
2
8
-34 -40 -46 -10 -16 -22 -28 -34 -40 -46 -16 -22 -28 -34 -40 -10 -16 -22 -28 -34 -40 -10 -16 -22 -28 -34 -40 -10 -16 -22 -28 -34
-10 -16 -22 -28 -34
Avg 7-day Max, oC
1-day Min, oC
(PRESSURE AGING VESSEL) PAV
ORIGINAL
> 1.00 kPa
< 5000 kPa
> 2.20 kPa
S < 300 MPa m > 0.300
Report Value
> 1.00 %
20 Hours, 2.07 MPa
10 7 4 25 22 19 16 13 10 7 25 22 19 16 13 31 28 25 22 19 16 34 31 28 25 22 19 37 34 31 28 25 40 37 34 31
(Dynamic Shear Rheometer) DSR G* sin d
( Bending Beam Rheometer) BBR “S” Stiffness & “m”- value
-24 -30 -36 0 -6 -12 -18 -24 -30 -36 -6 -12 -18 -24 -30 0 -6 -12 -18 -24 -30 0 -6 -12 -18 -24 -30 0 -6 -12 -18 -24
0 -6 -12 -18 -24
-24 -30 -36 0 -6 -12 -18 -24 -30 -36 -6 -12 -18 -24 -30 0 -6 -12 -18 -24 -30 0 -6 -12 -18 -24 -30 0 -6 -12 -18 -
24 0 -6 -12 -18 -24
Miscellaneous Spec Requirements
(Dynamic Shear Rheometer) DSR G*/sin d
(Dynamic Shear Rheometer) DSR G*/sin d
CEC
< 3 Pa.s @ 135 oC
> 230 oC Flash
Point
Mass
Loss
PG 64 - 16
PG 58-22
PG 52-28
PG 64-10 PG 58-16
> Many agencies have
established zones
PG Binder Selection
Developed from Air Temperatures
• Superpave Weather Database
– 6500 stations in U.S. and Canada
• Annual air temperatures
– hottest seven-day temp (avg and std
dev)
– coldest temp (avg and std dev)
• Calculated pavement temps used in PG
selection
> 20 years
Reliability
• Percent Probability of Not Exceeding Design
Temp
frequency of
observed temps
(Total area under
curve = 100 %)
Tavg Tdes
Reliability is area under curve
to the left of Tdes
> using Normal Distribution
36 40
7-Day Maximum Air Temperatures
50 % reliability
98 % reliability
Observed Air Temperatures Topeka, KS
average summer
very hot summer
> this data - standard
deviation of 2°C
36
40
-23 -31
0 10 20 30 40 50 60 -10 -20 -30 -40
Observed Air Temperatures
Topeka, KS
average winter
> standard
deviation of 4°C
very cold winter
Convert to Pavement Temperature
• Calculated by Superpave
software
• High Temperature
– 20 mm below surface of
mixture
• Low Temperature
– at surface of mixture
Pavt Temp = f ( Air Temp, Depth, Latitude )
56
60
-23 -31
0 10 20 30 40 50 60 -10 -20 -30 -40 70
Calculated Pavement Temperatures Topeka, KS
pvt = air
pvt > air
0 10 20 30 40 50 60 -10 -20 -30 -40 70
PG 64-34 (98% minimum reliability)
PG 58-28 (50 % minimum reliability)
PG Binder Grades Topeka, KS
PG grades - six degree
increments
0 10 20 30 40 50 60 -10 -20 -30 -40 70
PG 58-28 (50 % minimum reliability)
Effect of Rounding to Standard Grades
PG 58 provides 85% reliability
PG -28 provides 90% reliability
Effect of Rounding to Standard
Grades
needed grade
for 50% reliability
-23 -28
Minimum Pavement Temperatures
selected grade
for 50% reliability Rounding depends
on actual temps!
-16 -22 -28
Effect of Loading Rate on
Binder Selection
• Dilemma
– specified DSR loading rate is 10 rad/sec
– what about longer loading times ?
• Use binder with more stiffness at higher
temps
– slow - - increase one high temp grade
– stationary - - increase two high temp grades
– no effect on low temp grade
90 kph
Effect of Loading Rate on
Binder Selection
• Example
– for toll road PG 64-22
– for toll booth PG 70-22
– for weigh stations PG 76-22
90 kph
Slow
Stopping
Effect of Traffic Amount
on Binder Selection
• 10 - 30 x 106 ESAL
– Consider increasing - - one high temp
grade
• 30 x 106 + ESAL
– Recommend increasing - - one high
temp grade
80 kN ESALs
> Equivalent Single Axle Loads
ESAL Comparison
80 kN
18,000 lb.
100 kN
22,000 lb.
44 kN
10,000 lb.
1
ESAL
2.2
ESAL
.09
ESAL
67 kN
15,000 lb
0.48 ESAL
27 kN
6,000 lb
0.01 ESAL + =
151 kN
34,000 lb
1.10
151 kN
34,000 lb
1.10 + =
54 kN
12,000 lb
0.19 +
0.49 ESALs
2.39 ESALs
BIG TRUCK
Little Truck
PG 46 PG 52 PG 58 PG 64 PG 70 PG 76 PG 82
(Rotational Viscosity) RV
90 90 100 100 100 (110) 100 (110) 110 (110)
(Flash Point) FP
46 52 58 64 70 76 82
46 52 58 64 70 76 82
(ROLLING THIN FILM OVEN) RTFO Mass Loss < 1.00 %
(Direct Tension) DT
(Bending Beam Rheometer) BBR Physical Hardening
2
8
-34 -40 -46 -10 -16 -22 -28 -34 -40 -46 -16 -22 -28 -34 -40 -10 -16 -22 -28 -34 -40 -10 -16 -22 -28 -34 -40 -10 -16 -22 -28 -34
-10 -16 -22 -28 -34
Avg 7-day Max, oC
1-day Min, oC
(PRESSURE AGING VESSEL) PAV
ORIGINAL
< 5000 kPa
> 2.20 kPa
S < 300 MPa m > 0.300
Report Value
> 1.00 %
20 Hours, 2.07 MPa
10 7 4 25 22 19 16 13 10 7 25 22 19 16 13 31 28 25 22 19 16 34 31 28 25 22 19 37 34 31 28 25 40 37 34 31
(Dynamic Shear Rheometer) DSR G* sin d
( Bending Beam Rheometer) BBR “S” Stiffness & “m”- value
-24 -30 -36 0 -6 -12 -18 -24 -30 -36 -6 -12 -18 -24 -30 0 -6 -12 -18 -24 -30 0 -6 -12 -18 -24 -30 0 -6 -12 -18 -24
0 -6 -12 -18 -24
-24 -30 -36 0 -6 -12 -18 -24 -30 -36 -6 -12 -18 -24 -30 0 -6 -12 -18 -24 -30 0 -6 -12 -18 -24 -30 0 -6 -12 -18 -
24 0 -6 -12 -18 -24
How the PG Spec Works
(Dynamic Shear Rheometer) DSR G*/sin d
(Dynamic Shear Rheometer) DSR G*/sin d
< 3 Pa.s @ 135 oC
> 230 oC
CEC
58 64
Test Temperature
Changes
Spec Requirement
Remains Constant
> 1.00 kPa
Summary of How to Use
PG Specification
• Determine
–7-day max pavement temperatures
–1-day minimum pavement
temperature
• Use specification tables to select
test temperatures
• Determine asphalt cement
properties and compare to
specification limits
Questions - ?
82
Questions - ?