Performance of Rigid Pavements After 20 Plus Years 

The Long-Term Pavement 

Performance (LTPP) program 

provided support to the 

Transportation Pooled Fund 

Study TPF-5(291), “Development 

of a Specific Pavement Study 

(SPS)-2 Pavement Preservation 

Experiment,” which created a 

second-tier experiment based on 

the original SPS-2 experiment. The 

original experiment designed by 

the LTPP program examines the 

structural factors of rigid pavement. 

The objective of the pooled fund 

1

 Dufalla, N., Senn, K., Schmalzer, P., and Nichols Consulting Engineers (NCE). 2016. Development of SPS-2 Pavement Preservation 

Experiment—Final Phase I Report. Olympia, WA: Washington State Department of Transportation.

study was to determine the most 

cost-effective concrete preservation 

strategies to extend the service life 

of the aging pavements constructed 

from the mid-1990s to 2000. 

Figure 1 shows a U.S. map of the 

SPS-2 test site locations and the 

year of construction.

Under the leadership of the 

Washington State Department of 

Transportation (WSDOT), this study 

was conducted from 2014 to 2021, 

with funding support from six State 

departments of transportation 

(DOTs): Arizona, California, 

Colorado, Georgia, Kansas, and 

North Carolina. These agencies also 

served as the Technical Advisory 

Committee (TAC) for the study.

The research team for this study 

provided an early summary 

report entitled, Development of 

SPS-2 Pavement Preservation 

Experiment—Final Phase I Report, 

of the existing status of the 

various LTPP experiments to the 

TAC members, which included 

options for implementing a new 

pavement preservation field 

study within the active SPS-2 test 

sections still monitored by the 

LTPP program.1

 TAC members 

wanted to know if predicted 

pavement performance is reliable 

to use as a control for test sections 

receiving a pavement preservation 

treatment. Based on the research 

team’s analyses, the American 

Association of State Highway 

and Transportation Officials 

(AASHTO) AASHTOWare Pavement 

Mechanistic-Empirical (ME) Design 

predictions are not sufficiently 

accurate to serve as control 

© 2018 Larry Scofield.

Figure 1. Illustration. States showing location of 14 LTPP SPS-2 sites constructed 

from 1992 to 2000.

KEEPING OUR PARTNERS INFORMED

LTPP

Newsletter

August 2022

Summer Issue
KEEPING OUR PARTNERS INFORMED

Summer 2022 Issue LTPP NEWSLETTER PAGE 2

sections. This finding was a key 

element in the evolution of work 

conducted under the pooled fund 

study and is documented in Final 

Report—Comparison of Predicted 

and Actual SPS-2 Performance Using 

AASHTOWare PaveME.

2

The research team also conducted 

field visits to the sites, called 

SPS-2 Tech Days. Tech Days 

exposed a broader audience to 

the SPS-2 projects and obtained 

input for potential future activities. 

Most SPS-2 Tech Days included a 

classroom discussion of the SPS-2 

experiment, key findings, more 

details about the site, and an onsite 

field observation (figure 2). A typical 

Tech Day included approximately 

40 attendees, which were a mix 

of DOTs, industry, academia, and 

contractor personnel. Several 

Tech Days included workers who 

constructed or inspected the test 

sections during the 1990s. At the 

field walks, which were particularly 

well received, the participants 

were struck by the differences 

in performance between design 

features that were revealed over the 

more than 20 yr since construction. 

Table 1 shows the nine SPS-2 Tech 

Days conducted under this study.

SPS-2 Tech Days also provided 

multiple recommendations for 

additional analyses that would 

benefit the pavement community. 

Based on these recommendations, 

TAC approved the following studies 

(and others) to: 

• Determine deterioration rates 

to evaluate the impact of SPS-2 

experimental design features.

• Assess impacts of initial 

smoothness and shoulder 

type on performance, and the 

impact of design feature on load 

transfer efficiency using existing 

performance data including 

falling weight deflectometer, 

distress, and longitudinal profile.

2

 WSDOT. n.d. Comparison of Predicted and Actual SPS-2 Performance Using AASHTOWare PaveME. Olympia, WA: Washington State Department of Transportation.

• Assess previous analyses of SPS-2 

projects and update the analyses 

using the additional performance 

data collected since the original 

work was done. 

• Update the experimental 

matrix based on measured data 

as opposed to the assumed 

properties when the projects 

were nominated.

• Evaluate the impact of 

nonexperimental factors on 

pavement performance.

• Estimate the age of pavement 

at the time of failure based 

on projections of measured 

performance and selected 

failure criteria.

To see the full list of the studies 

performed between 2019–2021 

along with the documents 

referenced in this article, see 

the Documents section on the 

Transportation Pooled Fund website. 

For more information, contact 

Mustafa Mohamedali of WSDOT 

at mohamem@wsdot.wa.gov, 

or Deborah Walker of Federal 

Highway Administration (FHWA) 

at deborah.walker@dot.gov. 

© 2018 Kevin Senn. 

Figure 2. Photo. Washington Tech Day for 

SPS-2 field visit on May 2, 2018.

SPS-2 Tech Days

State Date Location

Arizona 2/21/2018 Phoenix

Colorado 3/23/2018 Denver

Washington 5/2/2018 Ritzville

Iowa 5/30/2018 Pleasant Hill

Kansas 10/2/2018 Abilene

North Dakota 10/16/2018 – 

10/17/2018 Bismarck/Fargo

California 3/12/2019 Stockton/Delhi

Arkansas 3/19/2019 Little Rock

Ohio 5/22/2019 Delaware 

Table 1. Completed SPS-2 Tech Days.
KEEPING OUR PARTNERS INFORMED

Summer 2022 Issue LTPP NEWSLETTER PAGE 3

Longitudinal Profile Diurnal 

Measurements Available in 

InfoPaveTM

The LTPP program initiated a 

special profile-monitoring data 

collection activity on jointed plain 

concrete pavements (JPCP) that 

was designed to capture changes 

in longitudinal profile roughness 

over a 1-d timeframe (i.e., diurnal 

measurement). The intent was to 

address noted differences in the 

International Roughness Index on 

JPCP over short durations limited 

to a single day.

In 2013, the LTPP program 

developed guidelines to collect 

diurnal measurements of 

longitudinal profile data at 

the program’s rigid pavement 

project sites (i.e., Strategic Study 

of Structural Factors of Rigid 

Pavements, SPS-2 Projects). The 

guidelines were updated in 2019 to 

include the JPCP from the following 

experiments: General Pavement 

Study (GPS) and Environmental 

Factors in the Absence of Heavy 

Loads Experiments (GPS-3 and 

SPS-8, respectively).3

The profile data were collected 

three times over the course of the 

day to gather information on how 

the slab changes as the temperature 

changes throughout the day. The 

target times were as follows:

• Early morning: 5–7 a.m., coldest 

surface relative to temperature 

of bottom of the slab.

• Midmorning or late evening: 

9–11 a.m. or 7–9 p.m., top 

and bottom of slab at the 

same temperature.

• Afternoon: 1–3 p.m., hottest 

surface relative to temperature 

of the bottom of the slab.

3

 Federal Highway Administration. 2015. The Long-Term Pavement Performance Program. Report No. FHWA-HRT-15-049. Washington, DC: 

Federal Highway Administration. https://www.fhwa.dot.gov/publications/research/infrastructure/pavements/ltpp/15049/15049.pdf, last accessed 

July 12, 2022. 

The LTPP InfoPaveTM Web portal 

contains 348 diurnal datasets 

representing testing at 230 test 

sections across 23 States, and some 

sections had multiple diurnal tests 

over the years. Since January 2013, 

test sections in the GPS-3 and SPS-2 

and SPS-8 experiments have had 

more than one profile run in a given 

day. Contact LTPP Customer Service 

Support Center at ltppinfo@dot.gov 

for help with locating these data. 

The LTPP program directive, 

Diurnal Collection of Longitudinal 

Profile Data on SPS-2, GPS-3, 

and SPS-8 Rigid Pavement Test 

Sections (P-58) provides more detail 

on this special profile monitoring 

data collection activity. For more 

information, contact Larry Wiser at 

larry.wiser@dot.gov.

Materials Testing Data Available 

from Warm-Mix Asphalt Projects

The Warm-Mix Asphalt Overlay 

of Asphalt Pavements Experiment 

(SPS-10) has been underway since 

2014. Test section recruitment, 

selection, and construction has 

been completed and the full suite 

of performance testing from the 

experimental design is being 

conducted. Part of the performance 

evaluation includes detailed 

materials about the sampling and 

testing of all pavement layers 

constructed at the test sections. 

The experiment called for scheduled 

materials sampling and testing from 

3 to 6 mo, 12 mo, and then again 

at 18 mo after construction of the 

warm-mix asphalt layers. 

To characterize the materials, 

bulk samples of subgrade and 

other unbound layers were 

obtained, and cores of bound 

layers were taken. An entire set 

of characterization tests are 

being performed, including sieve 

analysis, classification, Atterberg 

limits, standard proctor, moisture 

content, and resilient modulus 

on subgrade and unbound layers 

and Hamburg wheel track testing, 

dynamic modulus, and Fenix testing 

on the asphalt concrete mixes. The 

asphalt concrete binders are also 

being characterized.

While this dataset is developed 

and laboratory testing is ongoing, 

a substantial amount of new data 

are available at LTPP InfoPave. 

Under the Data tab, select the 

SPS-10 experiment and the 

materials data of interest. The 

information on InfoPave provides 

new asphalt materials data 

consisting of mixture, binder, and 

aggregate testing. This information 

includes dynamic modulus test 

results, which are a common input 

for modern pavement design. 

There are also new subgrade and 

unbound test results, including 

layer characterization and resilient 

modulus. More data will be available 

as the laboratory testing progresses.

Materials sampling and testing 

plans are custom designed for each 

SPS-10 project and available by 

contacting LTPP Customer Service 

Support Center at ltppinfo@dot.gov.

Diurnal data provided in LTPP InfoPave may be used to investigate 

the effect of time-of-day measurements, which can affect pay 

factors for pavement smoothness, pavement condition, and other 

important questions for State DOTs.
KEEPING OUR PARTNERS INFORMED

Summer 2022 Issue LTPP NEWSLETTER PAGE 4

Winners of the Inaugural 

2020–2021 LTIP Student Data 

Analysis Contest 

Four papers were selected for 

awards in the first Long-Term 

Infrastructure Performance (LTIP) 

Student Data Analysis Contest. The 

student winners are as follows:

Agnimitra Sengupta, Sudeepta 

Mondal, Ph.D., S. Ilgin Guler, 

Ph.D., and Parisa Shokouhi, Ph.D.

Pennsylvania State University

1st Place (Bridge): “A State-Based 

Hidden Markov Model Approach to 

Impact Echo Signal Classification”

Miaomiao Zhang, Hongren 

Gong, Yuetan Ma, Xi Jiang, and 

Baoshan Huang

University of Tennessee

1st Place (Pavement): “Nomogram 

for Predicting Asphalt Pavement 

Roughness after Preventive 

Maintenance Based on LTPP 

Longitudinal Analysis”

Muhammad Munum Masud

Michigan State University 

2nd Place (Pavement): “Guidelines 

for Effective Weigh-in-Motion (WIM) 

Equipment Calibration, Application 

for Modeling WIM Errors, and 

Comparison of the ASTM and 

LTPP Protocols”

Greg Seleznev

Howard Community College

3rd Place (Pavement): “Diagnosing 

Changes in WIM Measurement 

Accuracy and WIM Calibration 

Needs Using Data Visualization and 

Statistical Modeling Tools”

The LTIP Student Data Analysis 

Contest is designed to encourage 

students to use either the LTPP or 

Long-Term Bridge Performance 

(LTBP) Web portal, LTPP InfoPave

or LTBP InfoBridgeTM,to address 

specific infrastructure issues or 

challenges. The LTPP program has 

a long tradition of student contests, 

and this was the inaugural year 

for the LTBP program student 

contest. This is also the first year 

a student from a community 

college submitted a paper using the 

InfoPave Web portal and placed in 

the contest.

Congratulations to the winners 

and thank you to everyone who 

participated in this year’s contest.

In Brief

LTPP First Analysis-Ready Dataset 

to Be Released This Summer

The LTPP program recognizes 

that understanding and using the 

data is not an easy undertaking 

for users, so over the past 2 yr, 

we have developed a workplan to 

create analysis-ready datasets for 

database users. We are pleased 

to announce that the LTPP 

Analysis-Ready Materials Dataset 

is the first to be created and will 

be available this summer with the 

release of the 36th Standard Data 

Release. Technical and promotional 

materials will accompany the 

release of this dataset and describe 

the process the program used to 

populate it.

The program has started initial 

discussions to develop the 

analysis-ready performance 

dataset, which is another important 

dataset for LTPP database users.

LTPP’s Impact Abroad

LTPP InfoPave is gaining attention 

in France. Eshan Dave, a member 

of the FHWA Expert Task Group for 

the LTPP program, is on sabbatical 

at Université Gustave Eiffel, Nantes 

campus (formerly, Laboratoire 

Central des Ponts et Chaussées, 

and the French Institute of Science 

and Technology for Transport, 

Development and Networks).

Eshan demonstrated InfoPave 

to researchers and students at 

Université Gustave Eiffel during his 

stay there and introduced InfoPave 

to the international delegation that 

participated in the data science 

workshop in conjunction with 

the 6th International Conference 

on Accelerated Pavement 

Testing (APT) on April 3 (figure 3). 

Eshan also introduced InfoPave 

resources to French transportation 

agency and industry members 

at the 2022 Journées Techniques 

Route (which means Road Technical 

Days) event in May. It is a 2-d event 

that is held every year in France 

for all road-related professionals 

to catch up on the latest 

technical developments.

© 2022 Eshan Dave. 

Figure 3. Photo. Audience attending the APT Conference on April 3, 2022.
Summer 2022 Issue LTPP NEWSLETTER PAGE 5

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find FHWA’s latest news, information, 

and resources.

HRDI-30/08-22(WEB)E 

FHWA-HRT-22-093

Recommended citation: Federal Highway Administration, 

LTPP Newsletter Summer 2022 Issue (Washington, DC: 2022)

https://doi.org/10.21949/1521923.

Transportation Pooled-Fund 

Solicitations

There are two active research 

solicitations involving the LTPP 

program. One is to continue the 

forensic investigations of LTPP test 

sections (Solicitation 1560), and the 

other is to look at the performance 

of pavement preservation 

treatments (Solicitation 1581). We 

encourage you to consider being a 

partner in these new efforts.

New Publications

Reports

Long-Term Pavement Performance 

Information Management System 

User Guide

FHWA-HRT-21-038

[PDF]

Exploring the Importance of Traffic 

Data Input Levels for MechanisticEmpirical Pavement Design

FHWA-HRT-21-046

[PDF]

LTPP Manual for Collecting and 

Processing Longitudinal Profile, 

Macrotexture, and Transverse 

Profile Data

FHWA-HRT-21-096

[PDF] 

TechBriefs 

Acceptance Testing of High-Speed 

Transverse Profile Measuring Systems 

Purchased for the Long-Term

Pavement Performance Program

FHWA-HRT-20-023

[PDF]

Long-Term Pavement Performance 

Data Analysis Plan

FHWA-HRT-21-088

[PDF] 

Brochure

FHWA InfoTechnology

FHWA-HRT-22-009

[PDF]