performance evaluation of asphalt pavement preservation ... eval of pavt... · performance...

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Slide No. 1

Performance Evaluation of Asphalt Pavement Preservation Activities in Nevada

Elie Y. Hajj, Ph.D.

University of Nevada, Reno (UNR)Western Regional Superpave Center

2013 Utah Asphalt ConferenceSalt Lake CityMarch 27, 2013

Slide No. 2

Key Factor for Success

Reliable Estimation of

long-term performance

Introduction

Pavement Preservation

Increase pavement longevity

Provide Safe & comfortable ride for the road users

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Slide No. 3

Introduction

• Main objective of a preservation activities:– Maintain the current condition

– Slow down the rate of deterioration

• Not intended to increase the structural capacity.

Slide No. 4

Overall Objective

• In attempt to optimize the use of funds, Nevada DOT sponsored this research study to develop an effective preservation activities program for Nevada’s flexible pavements.

• Developed program will help in: – Selection of consistent, effective & efficient strategies,– Provide guidance to ensure uniform and quality

maintenance practices.

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Slide No. 5

Identification of Preservation Activities Implemented by NDOT

• Chip seal: asphalt binder overlaid by a layer of embedded aggregate– Emulsion: SS-1, SS-1h, CSS-1 or CSS-1h, LMCRS-2 or LMCRS-2h.

• Sand seal: emulsion followed by a sand layer. – RS-1, CRS-1, MS-1 or HFMS-1.

• Scrub seal: polymer-modified emulsion, sweeping or squeegee followed by a sand layer. – Poly-methyl-phenyl-silane (PMPS) emulsions

Slide No. 6


• Fog seal: application of SS emulsion diluted with water– Emulsions: SS-1, SS-1h, CSS-1 or CSS-1h.

• Crack filling: cleaning of cracks and filling them with rubberized asphalt, rejuvenating agent, emulsion, or liquid asphalt (cutback). – hot-applied CRAFCO PolyFlex crack filler sealants Type 1, Type 2

and Type 3 were used depending on the climatic zone.

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Slide No. 7


• Maintenance overlay cold mix (MO-CM):– Small paver – small roller compactor. – CMS-2S (AC-10 base asphalt)

• Machine patching paver laid plantmix (MP-PLP):– Dense graded HMA– Small paver – small roller compactor. – PG64-28NV (northern NV), PG76-22NV (southern NV).

Slide No. 8


• Machine patching blade laid cold mix (MP-BLC): restore surface lost to raveling vertical difference > 1” in 10 ft.– Max 2” thick– < 300 yd3 or 550 tons in 10 mile section– CMS-2S (AC-10 base asphalt)

• Machine patching blade laid plantmix (MP-BLP): – Dense graded HMA laid down from the truck– Motor-grader– PG64-28NV (northern NV), PG76-22NV (southern NV).

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Slide No. 9

Research ApproachAssessing Performance

• Review of NDOT maintenance records– 15 years– 17,000 preservation activities– Construction date, location, costs

(labor, equipment and materials)…

• Criteria for treatment selection– Road classification (SR, US or IR)– Location (Districts 1,2 and 3 / Counties)– Project length: 1 mile

District 3

District 1

District 2

Results:847 sections were identified for

evaluation

Slide No. 10


• Analysis of NDOT Pavement Management System (PMS)

– Distress data Rutting, fatigue cracking, thermal cracking and smoothness.

– Present Serviceability Index (PSI)

• Analysis of NDOT Maintenance Management System (MMS)

INTEGRATE MMS and PMS Databases

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Slide No. 11


• Match exact location of field sections from PMS with MMS.

Two different and separate databaseDifferent codes assigned for same routes.

Microsoft Access database was developed

Slide No. 12

Research ApproachMS Access Database

Maintenance database

PMS database

Query:

County Route Initial MP Final MP

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Slide No. 13


County Route Initial MP Final MP Survey date PSI

Slide No. 14


County Route Initial MP Final MPMaintenance Technique

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Slide No. 15

Present serviceability index (PSI)

• The PSI is correlated to various pavement measurements (i.e. roughness, rutting, cracking, and patching) and provides an indication of the overall pavement condition.

5 . 1.38 0.03

where, IRI = international roughness index (in/mile), RD = rut depth (in), C = cracking (ft2/1000ft2), and P = patching (ft2/1000ft2).

Slide No. 16

Present serviceability index (PSI)

• The PSI values range from 5 for a pavement with a very good condition to a value of 0 at the extreme low end for a pavement with a very poor condition.

• The terminal (or failure) serviceability (PSI) is the minimum level of serviceability the agency allows in design.

• NDOT pavements:– U.S. Routes (US) and Interstates (IR) designed for a

minimum PSI (terminal serviceability) of 2.5.

– State Routes designed for a minimum terminal serviceability of 2.0.

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Slide No. 17

Performance Data Analysis

0.0

1.0

2.0

3.0

4.0

5.0

11/3

/198

8

5/7/

1990

11/8

/199

1

5/11

/199

3

11/1

2/19

94

5/15

/199

6

11/1

6/19

97

5/20

/199

9

11/2

0/20

00

5/24

/200

2

11/2

5/20

03

5/28

/200

5

11/2

9/20

06

PSI

Years

CL-SR164-6.4-9.2

Average PSI Chip seal

Slide No. 18


0.0

1.0

2.0

3.0

4.0

5.0

11/3

/198

8

5/7/

1990

11/8

/199

1

5/11

/199

3

11/1

2/19

94

5/15

/199

6

11/1

6/19

97

5/20

/199

9

11/2

0/20

00

5/24

/200

2

11/2

5/20

03

5/28

/200

5

11/2

9/20

06

PSI

Years

ES-SR265-16-15.5

Average PSI Chip seal Maintenance overlay cold mix

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Slide No. 19


Prevent4.2

3.0

2.5

2.0

Improve/Extend

Hold

Objective PerformanceState

Routes

PSI

Time

Hold

Improve/Extend

4.2

3.5

2.8

2.5

US. Routes and IR

Failure

Slide No. 20

Hold

Improve/Extend

1.9

2

2.1

2.2

2.3

2.4

2.5

2.6

2.7

2.8

2.9

3

12/8/1989 6/11/1991 12/12/1992 6/15/1994 12/17/1995 6/19/1997 12/21/1998 6/23/2000

PSI

YearsChip seal Average PSI

Pre-trt PSI:1 yrImprove/Extd: 3 yr

Analysis ApproachExample: State Route

Performance: 4.0 – 6.2 yr

Failure Criteria

Hold: 3.2 yr

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Slide No. 21

Analysis ApproachExample

• Project level analysis: Example table – State Route

Section ID PSITrt.Obj.

Treatment performance Years to

reach the

pre-trtPSI

Perf. Range (years)

Benefit (B) PSI

Improve/ Extend, years (PSI > 2.5)

PSI

Hold, years (PSI

2.5)

PSI

ES-SR266-25-29.3 2.3 Hold 2.6 3.0 2.5 3.0 2.1 3.8 3.8-6.0 3.5

CL-SR168-4.7-8 A 2.6Improve/Extend

2.9 2.1 2.5 2.0 2.0 2.0 2.0-4.1 4.2

Slide No. 22


• Project level analysis: Benefit– Area under the performance curve.

1.9

2.1

2.3

2.5

2.7

2.9

12/8/1989 6/11/1991 12/12/1992 6/15/1994 12/17/1995 6/19/1997 12/21/1998 6/23/2000Pres

ent s

ervi

ceab

ility

inde

x (P

SI)

YearsChip seal Average PSI

Chip seal

Failure Criteria

AREA

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Slide No. 23


• Benefit-cost Ratio is a good indication of treatment effectiveness.Cost per lane-mile includes:

> Labor> Materials> Equipment

B/C =

Slide No. 24

Detailed Results for Chip Seal Performance

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Slide No. 25

Overall Performance of Chip Seal

Treatment objective

Total number of sections

Treatment performance, number of sections (percent of

total)

Improve/Extend Hold/Maintain

Hold 65 38 (58%) 27 (42%)

Improve/Extend 33 22 (67%) 11 (33%)

Prevent 24 24 (100%) 0 (0%)

Slide No. 26

Performance Periods for Chip Seal

2.0 1.6 1.7

3.42.6 2.5

0.0

2.0

4.0

6.0

8.0

10.0

1 2 3

Perf

orm

ance

Per

iod

Nevada District

3.22.6 2.5

5.65.0 4.8

0.0

2.0

4.0

6.0

8.0

10.0

1 2 3

Perf

orm

ance

Per

iod

Nevada District

HOLD/MAINTAIN IMPROVE/EXTEND

DISTRICT

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Slide No. 27

Performance Periods for Chip Seal

HOLD/MANTAIN IMPROVE/EXTEND

ROUTE

2.1 1.8

0.9

3.3 3.2

1.3

0.0

2.0

4.0

6.0

8.0

10.0

SR US IR

Perf

orm

ance

Per

iod

Road Classification

3.52.7

1.4

6.9

4.5

3.1

0.0

2.0

4.0

6.0

8.0

10.0

SR US IR

Perf

orm

ance

Per

iod

Road Classification

Slide No. 28

Benefit-Cost Ratio (B/C) for Chip Seal


DISTRICT

26 32 270

255075

100125150175200

1 2 3

B/C

Nevada District

57 54 54

0255075

100125150175200

1 2 3

B/C

Nevada District

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Slide No. 29

B/C for Chip Seal


ROUTE

4020 24

0255075

100125150175200

SR US IR

B/C

Road Classification

77

41 41

0255075

100125150175200

SR US IR

B/C

Road Classification

Slide No. 30

Existing Pavement Distresses

Trea

tmen

t

Trea

tmen

t O

bje

ctiv

e

Trea

tmen

t P

erfo

rman

ce

Pre-Treatment Condition

Fat

igu

e C

rack

ing

(f

t2)

Tran

sver

se

Cra

ckin

g

(ft)

Blo

ck

Cra

ckin

g

(ft2

)

Ru

t D

epth

s (i

nch

)

IRI

(in

ch/m

ile)

Ave SD

Ave SD

Ave SD

Ave SD

Ave SD

State Routes

Chip Seal

H/M 62% chance of I/E 537 48 46 2 269 15 0.16 0.01 181 10

I/E 91% chance of I/E 456 24 37 2 218 13 0.13 0.01 147 9

H/M Denotes Hold/MaintainI/E Denotes Improve/Extend

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Slide No. 31

Overall Performance

• Chip seals were effective on – SR regardless of pre-treatment PSI

– on US/IR routes with a pre-treatment PSI > 2.8.

– Higher benefit on SR roads

• Sand seals :– more effective on SR with a pre-treatment PSI > 2.5.

– effectiveness on SR with a pre-treatment PSI < 2.5 was similar to its effectiveness on US with a pre-treatment PSI < 2.8.

– Sand seals were not applied on IR.

Slide No. 32

Overall Performance

• Scrub seals:– effectiveness on SR with a pre-treatment PSI > 2.5 was similar to its

effectiveness on US with a pre-treatment PSI > 2.8.

– A low benefit was found for the scrub seal when applied to SR and US roads with a pre-treatment PSI < 2.5 and 2.8, respectively.

– Scrub seals were not applied on IR.

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Slide No. 33

Overall Performance

• Fog seals – Low benefit on SR and US/IR.

– Most benefit of fog seals when pre-treatment PSI > 2.5 and 2.8 for SR and US/IR roads.

• Crack fillings– More effective when applied to SR when compared to US/IR roads

specifically when the pre-treatment PSI > 2.5.

Slide No. 34

Overall Performance

• Maintenance overlay cold mix (MO-CM):– Effective on SR and US roads.

– Highest benefit on SR with a PSI > 2.5.

• Machine patching paver laid plantmix (MP-PLP) – Highly effective on SR and US roads.

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Slide No. 35

Overall Performance

• Machine patching blade laid cold mix (MP-BLC) – Low benefit on SR and US roads.

– Highest benefit when applied to PSI > 2.5 and 2.8 for SR and US.

• Machine patching blade laid plantmix (MP-BLP) were – More effective on SR when compared to US/IR roads.

– Effectiveness on SR was similar to its effectiveness on US/IR roads with a pre-treatment PSI > 2.8.

Slide No. 36

Overall Recommendations

• A pavement preservation program was suggested to NDOT.

• Maintenance activities depends on:– PSI

– Roughness

– Pavement distresses: Fatigue, block and transverse cracking

Rut depths

• Activities recommended if B/C > 25.0

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Slide No. 37

Overall Recommendations – State Routes

Slide No. 38


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Slide No. 39


Slide No. 40


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Slide No. 41

Overall Recommendations – US/IR Routes

Slide No. 42


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Slide No. 43


Slide No. 44

Visit our websites at:

www.wrsc.unr.edu

www.arc.unr.edu

Contact Information:

Elie Y. Hajj, [email protected], 775-784-1180

Thank you for your attendance

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