marvin traylor - purdue university
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Marvin Traylor
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PERPETUALPERPETUAL
PAVEMENTPAVEMENTAnd Selected Short Subjects
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• Initial Costs• Out Year Costs• User Delay Costs
A ModernLife Cycle Cost Analysis
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Score Card
User Delay CostsOut Year CostsInitial Costs
HMAPCC
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0102030405060708090
100
MostRoutes
CongestedRoutes
Tota
l Cos
t (%
)
User Delay CostsOut Year CostsInitial Costs
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7
8
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Breakout by Majority Pavement Type – Interstate System
Data source: US DOT, FHWA, Highway Statistics, Section V, Type of Surface, Interstate – Rural and Urban
Asphalt - 32 statesConcrete - 18 states
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“AASHO Road Test”
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THICKNESS
312 5 612 8 912 11 1212
0 3 6 9
0
10”
20”
8
3
PCC
SANDY GRAVEL subbase
MATERIAL
Rigid Profile
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ASPHALT surface
CRUSHED STONE base
SANDY GRAVEL subbase 1612840
9630
65432
MATERIAL THICKNESS
0
10”
20”
3
6
8
Flexible Profile
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LANE 1 LANE 2
2 Years = 1.1 Million Axle Loads
Loading
LOOP
303096222265181864121243
484812404093232924246
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Pavement PerformanceP.
S.I.
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Pavement PerformanceP.
S.I.
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Subbase Necessary to
Prevent Pumping
Rigid Findings
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Rigid Nomograph
SOIL
TRA
FFIC
THIC
KN
ESS
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SOIL
TRA
FFIC
THIC
KN
ESS
Rigid Nomograph
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SOIL
TRA
FFIC
THIC
KN
ESS
Rigid Nomograph
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Flexible Findings
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Structural Number Concept
.44
.14
.11
4”
9”
16”
= 1.76
= 1.26
= 1.76
= 4.78
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S.N
.
TRA
FFIC SOIL
Flexible Nomograph
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S.N
.
TRA
FFIC SOIL
Flexible Nomograph
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S.N
.
TRA
FFIC SOIL
Flexible Nomograph
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•Equivalent 18K Single Axle Loads (ESALs)
•Thickness Designs for both B & W
•“Equivalent” Pavements
AASHO Advances
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•One Set of Materials
•Two Years of Weathering
•1.1 Million Axles
•No Full Depth
•Totally Empirical
AASHO Limitations
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Mechanistic Design
Mechanistic -
“Concerning the Relationships Between Applied Forces and Material Responses.”
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Mechanistic -
“Concerning the Relationships Between Applied Forces and Material Responses.”
Basic Premise -
Low Deflections = Long Life
Mechanistic Design
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Strain Fatigue LifeStra
in
High Strain = Short Life
Low Strain = Long Life
Fatigue Theory
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Fatigue Cracking
RepeatedBending
Leads toFatigue Cracking
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RepeatedBending
Leads toFatigue Cracking
Fatigue Cracking
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TRL Report 250Nunn, Brown, Weston& Nicholls
Design of Long-Life FlexiblePavements for Heavy Traffic
http:\\www.trl.co.uk
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“The deterioration ofthick, well constructed,fully flexible pavementsis not structural, butoccurs at the surface ascracking and rutting.”
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Professor MonismithUniversity of California, Berkeley
1972 AAPT Proceedings
“Moreover, based on recent studies, it was assumed that
strains less than 70 x 10-6 would cause no fatigue damage.”
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High Strain = Short Life
Low Strain = Unlimited Life
UnlimitedFatigue
Life
Fatigue LifeStrain
Stra
in
Fatigue Theory forThick Pavements
70
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37
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4000
5000
6000
7000
8000
0.0E+00 5.0E+06 1.0E+07 1.5E+07 2.0E+07 2.5E+07 3.0E+07 3.5E+07 4.0E+07
Number of Load Cycles
Stiff
ness
, Mpa
70 Micro Strain Test
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0.00001
0.0001
0.001
0.01
1.0E+02
1.0E+04
1.0E+06
1.0E+08
1.0E+10
1.0E+12
1.0E+14
Load Cycles to 50% Stiffness (Failure)
Stra
in (S
trai
n/1E
6)
?
Traditional Fatigue Plot
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Fatigue-Based Thickness
35404550607080100
Microstrain
22.019.018.016.515.013.512.510.5
Thickness
302015105321
TF
TF1 = 200 Trucks/Day
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TF1 = 200 Trucks/Day35404550607080100
Microstrain
22.019.018.016.515.013.512.510.5
Thickness
302015105321
TF
Fatigue-Based Thickness
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FAILURE MODES
43Eventual Distress
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45
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Perpetual Structure
20 Year Roof
Foundation
Perpetual Pavement
Strain
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• Thinner Sections• No Full-Depth Patching• Rapid/Inexpensive Rehab• Permanent Elevations
Advantages
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Dollars & Days
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30 Year Concrete
Year Activity $ (millions) Days
0 New Construction 4.0 6010 2030 Patch/Overlay 0.4 6040 Patch/Overlay 0.4 6050 Reconstruction 4.0 60607080 Patch/Overlay 0.4 6090 Patch/Overlay 0.4 60
100 Reconstruction 4.0 60
TOTAL $13.6 420
Dollars & Days
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30 Year Concrete
Year Activity $ (millions) Days
0 New Construction 4.0 6010 2030 Patch/Overlay 0.4 6040 Patch/Overlay 0.4 6050 Reconstruction 4.0 60607080 Patch/Overlay 0.4 6090 Patch/Overlay 0.4 60
100 Reconstruction 4.0 60
TOTAL $13.6 420
Perpetual Pavement
Year Activity $ (millions) Days
0 New Construction 3.0 3010 20 Mill/Overlay 0.3 1530 40 Mill/Overlay 0.3 1550 60 Mill/Overlay 0.3 157080 Mill/Overlay 0.3 1590
100 Mill/Overlay 0.3 15
TOTAL $4.8 105
Dollars & Days
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Rubblizing
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Microstrain
< 70
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Dollars & Days*
1059055Days
3.93.51.9$
30 Yr. PCC
20 Yr. PCCRubblize
* All figures for One Mile of 4-Lane Divided Pavement
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Score Card
User Delay CostsOut Year CostsInitial Costs
HMAPCC
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InitialCosts
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Alternate Pavements
13” HMA
12” Modified Soil
4” HMA Subbase
8” PCC
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Engineer’s Estimate(Total Project)
$2,331,134$2,445,407
BLACKWHITE
5% Difference
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Actual Bids(Total Project)
$2,343,458CALHOUN
$1,779,209MERRILL
$1,772,477SANKEY
$1,599,992FLATT
$1,599,532$2,114,322FREESEN
BLACKWHITE
32% Difference
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Score Card
User Delay CostsOut Year Costs
XInitial CostsHMAPCC
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Out YearCosts
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KansasInterstate
Study
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Interstate/Kansas Turnpike
PCC Pavement (184 miles)
HMA Pavement (244 miles)
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HMA
Total Expenditures Per 4-Lane Mile Per Year, HMA Pavements, I-70
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PCC
Total Expenditures Per 4-Lane Mile Per Year, PCC Pavements, I-70
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Expenditures per 4-Lane Mile, 2001 $Pavement Original Average Cost Per Year
Type Construction 0-20 Years >20 Years
$33,794$23,358$613,388HMA
$94,632$19,578$823,872PCC
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Average Life Cycle Cost
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Score Card
User Delay CostsXOut Year CostsXInitial Costs
HMAPCC
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User DelayCosts
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Score Card
XUser Delay CostsXOut Year CostsXInitial Costs
HMAPCC
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Marvin Traylor
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