1

Marvin Traylor

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PERPETUALPERPETUAL

PAVEMENTPAVEMENTAnd Selected Short Subjects

3

• Initial Costs• Out Year Costs• User Delay Costs

A ModernLife Cycle Cost Analysis

4

Score Card

User Delay CostsOut Year CostsInitial Costs

HMAPCC

5

0102030405060708090

100

MostRoutes

CongestedRoutes

Tota

l Cos

t (%

)

User Delay CostsOut Year CostsInitial Costs

6

7

8

9

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

10

“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

12

ASPHALT surface

CRUSHED STONE base

SANDY GRAVEL subbase 1612840

9630

65432

MATERIAL THICKNESS

0

10”

20”

3

6

8

Flexible Profile

13

LANE 1 LANE 2

2 Years = 1.1 Million Axle Loads

Loading

LOOP

303096222265181864121243

484812404093232924246

14

Pavement PerformanceP.

S.I.

15

Pavement PerformanceP.

S.I.

16

Subbase Necessary to

Prevent Pumping

Rigid Findings

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Rigid Nomograph

SOIL

TRA

FFIC

THIC

KN

ESS

18

SOIL

TRA

FFIC

THIC

KN

ESS

Rigid Nomograph

19

SOIL

TRA

FFIC

THIC

KN

ESS

Rigid Nomograph

20

Flexible Findings

21

Structural Number Concept

.44

.14

.11

4”

9”

16”

= 1.76

= 1.26

= 1.76

= 4.78

22

S.N

.

TRA

FFIC SOIL

Flexible Nomograph

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S.N

.

TRA

FFIC SOIL

Flexible Nomograph

24

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

32

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

36

37

38

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

40

Fatigue-Based Thickness

35404550607080100

Microstrain

22.019.018.016.515.013.512.510.5

Thickness

302015105321

TF

TF1 = 200 Trucks/Day

41

TF1 = 200 Trucks/Day35404550607080100

Microstrain

22.019.018.016.515.013.512.510.5

Thickness

302015105321

TF

Fatigue-Based Thickness

42

FAILURE MODES

43Eventual Distress

44

45

46

Perpetual Structure

20 Year Roof

Foundation

Perpetual Pavement

Strain

47

• Thinner Sections• No Full-Depth Patching• Rapid/Inexpensive Rehab• Permanent Elevations

Advantages

48

Dollars & Days

49

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

50

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

51

Rubblizing

52

53

54

Microstrain

< 70

55

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

57

InitialCosts

58

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

62

Out YearCosts

63

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

66

PCC

Total Expenditures Per 4-Lane Mile Per Year, PCC Pavements, I-70

67

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

69

Score Card

User Delay CostsXOut Year CostsXInitial Costs

HMAPCC

70

User DelayCosts

71

72

Score Card

XUser Delay CostsXOut Year CostsXInitial Costs

HMAPCC

73

Marvin Traylor