Long Term Pavement

Performance (LTPP)

LTPP’s GOAL is…

HOW and WHY

to provide answers

to

pavements perform as they

do!

Strategic Study of

Structural Factors for

Rigid Pavements

Largest on Going

Concrete Pavement

Research Project in

the World

1. Thickness

2. Base Type

3. Concrete Strength

4. Lane Width

5. Drainage

How Was SPS-2 Deployed

Statistical Design Called for 12 test sections to be

constructed in each of 16 states (14 States)

Statistical Design Called for 192 test sections to

be built (168 Constructed)

Statistical Design called for SPS-2 Core

Experiment (12 TS) to have Four States in Each

of Four Climate Zones (?)

PCCP Design Elements

1. Thickness

2. Base Type

3. Concrete Strength

4. Lane Width

5. Drainage

Shoulder Type

Time Line of SPS-2 Experiment

0

1

2

3

4

5

6

7

1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000

Meetings Construction Guidelines

It is anticipated that only a few SPS-2 projects will be built during the 1990 construction season. The remaining test sites will be selected from the

identified candidates scheduled for construction in 1991, or even 1992 if necessary

KS CA5 2 2 2 1

AZ

Time Line of SPS-2

Experiment

0

1

2

3

4

5

6

7

92 93 94 95 96 97 98 99 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17

Reports Construction Guidelines

26 Years

Analysis

of Fault

Data

Effects of

Subsurface

Drainage

Initial

Evaluation &

Analysis

Influence of

Design

Features

Curl & Warp

Analysis

SPS-2 Construction Outlet Inspection

Traffic Levels on SPS-2 Experiments

The Arizona Concrete Pavement Experiment (SPS-2)

Project

MP 106 EB

Google Earth Image of Test Sections

Hassyampa

River Palo

Verde

Rd

Johnson

Rd

Approaching from the West End

MP 106 EB 611 ft

Test Section

Layout

205 205 250 550 220 220 475 205 265 295 250 235 205 500 249 151 200 200 200 236

Base TypesDense Graded Aggregate Base (4" & 6")

Permeable Bituminous Treated Base (4") Note: These are the only Sections with Edge Drains

Lean Concrete Base (6")

Bituminous Treated Base (4")

Shoulder Types12 ft Shoulder Width

14 ft Shoulder Width

Un Dowelled Sections

267 268

State Supplemental @550 psi Flexural Strength550 psi Flexural Strength

216 215 223 219 217 221 213

900 psi Flexural Stength

214 218222 220 224 262 263 264 265 266

Design Features:

• PCCP Thickness- (2)

• Base Type- (3)

• Concrete Strength- (2)

• Lane Width- (2)

• Drained or Undrained

19 PCCP Test Sections

Arizona Project Construction Timeline(6 - 9 months)

•Removing Existing EB AC and Constructing Detour onto WB

•Over Excavating Existing Subgrade 1 ft and Recompacting

•Constructing Edge Drains

•Constructing Aggregate Base, Lean Concrete Base, and

Permeable Base

•Constructing 8”, 11” and 12.5” Thick PCCP

•Constructing 550 and 900 psi Flexural Strength PCCP

•Constructed Doweled and Undoweled PCCP

Construction

28

Open to Traffic

WimCalibration

Edge Drain

PATB

BTB

LCB

PCCP

Acceptance

27

1994

PCCPMix Design

PCCPMix Design

ACMill Remove

ABC

Over ExSubgrade Prep

January

Project

November December

22

Lab

Clearing &GrubDetour Const

June July August September October

Project Begins

Feb 16, 1993

March April May

Subgrade Preparation

Slots

PATB

DGAB

LCB

•Night Paving September 1993

• Three Mixes Used (1” & 1.5”)

• All LTPP Sections Doweled

16 ft22 ft

12 Ft

14 Ft

So What Have We

Learned After 25

Years

Shoulder

Travel Lane

LCB

PATB

DGAB

BEST

GOOD

WORST

900 PSI

550 PSI

14 Ft

12 Ft

Thicker is

Better

Comparison of Doweled to

Undoweled

205 205 250 550 220 220 475 205 265 295 250 235 205 500 249 151 200 200 200 236

Base TypesDense Graded Aggregate Base (4" & 6")

Permeable Bituminous Treated Base (4") Note: These are the only Sections with Edge Drains

Lean Concrete Base (6")

Bituminous Treated Base (4")

Shoulder Types12 ft Shoulder Width

14 ft Shoulder Width

262 263 264 265 266

900 psi Flexural Stength

214 218222 220 224 216 215 223 219 217

Un Dowelled Sections

267 268

State Supplemental @550 psi Flexural Strength550 psi Flexural Strength

221 213

SPS-2 Core Experiment 12 TS

SPS-2A JPCP 6 TS

SPS-2B JRCP 12 TS

State Supplemental Sections

North Dakota

8” PCCP

Kansas

North Dakota

Wisconsin

Issues with LTE as Performance

Measure

y = -0.6774x + 91.348R² = 0.4484

y = -0.7237x + 92.143R² = 0.6407

y = 0.1859x + 87.614R² = 0.0536

y = -0.4512x + 92.674R² = 0.3103

0

10

20

30

40

50

60

70

80

90

100

0 5 10 15 20 25 30

Load

Tra

nsf

er

Effi

cie

ncy

(%

)

Time (years)

8 " 550 PCCP 6" DGAB 12 (201)8 " 900 PCCP 6" DGAB 14(202)

11 " 550 PCCP 6" DGAB 14(203)

11 " 900 PCCP 6" DGAB 12(204)

CP Tech Center Threshold

201

202

203

204

0

10

20

30

40

50

60

70

80

90

100

0 5 10 15 20 25 30Lo

ad T

ran

sfe

r Ef

fici

en

cy (

%)

)

8" 550 PCCP 6" LCB 14 (217)

8" 900 PCCP 6" LCB 12 (218)

11" 550 PCCP 6" LCB 12 (219)

11" 900 PCCP 6" LCB 14 (220)

CP Tech Center Recommendation for DBR

Transverse Crack Count as

Performance Measure

Conclusions (My Opinions)

PATB Performed Best for Initial Smoothness

and Rate of Progression of Roughness

LCB performed worst with transverse

cracking and most influence of Widened

Shoulder

550 psi Mix Out Performed 900 psi

Widened Traffic Lanes Create a Higher

Potential for Longitudinal Cracking

SPS-2 Pooled Fund Reports

NCE Report:

SPS-2 PAVEMENT PRESERVATION

EXPERIMENT COMPARISON OF PAVEMENTME

AND ACTUAL PERFORMANCE

SPS-2 Pooled Fund Reports

Arizona SPS-2 Tech Day

Thank You!

The End!