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Publication Number: FHWA-RD-02-071
Date: March 2005

Study of LTPP Pavement Temperatures

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Since its inception, the Long-Term Pavement Performance (LTPP) program has been collecting temperature data from the General Pavement Studies (GPS) and Specific Pavement Studies (SPS) test sections. Temperature has a strong effect on pavement deflection test results, primarily in asphalt concrete, but also in portland cement concrete structures. Adjustment for temperature is made to deflection test results; and, for this reason, complete and accurate data on surface temperature and in-depth temperature of pavement structures are needed for future LTPP analysis and research. This study documents the first detailed review of the LTPP pavement temperature data elements. The report assesses the completeness and quality of the data, identifies anomalies in the data, and recommends remedial action for these anomalies.

T. Paul Teng, P.E.
Director, Office of Infrastructure
Research and Development


This document is disseminated under the sponsorship of the U.S. Department of Transportation in the interest of information exchange. The U.S. Government assumes no liability for its contents or use thereof. This report does not constitute a standard, specification, or regulation.

The U.S. Government does not endorse products or manufacturers. Trade or manufacturers' names appear herein only because they are considered essential to the objective of this document.

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The Federal Highway Administration (FHWA) provides high-quality information to serve Government, industry, and the public in a manner that promotes public understanding. Standards and policies are used to ensure and maximize the quality, objectivity, utility, and integrity of its information. FHWA periodically reviews quality issues and adjusts its programs and processes to ensure continuous quality improvement.


Technical Report Documentation Page

1. Report No.


2. Government Accession No.

3. Recipient's Catalog No.

4. Title and Subtitle

Study of LTPP Pavement Temperatures

5. Report Date

March 2005

6. Performing Organization Code

7. Author(s)

E.O. Lukanen, R.N. Stubstad, and M.L. Clevenson

8. Performing Organization Report No.

9. Performing Organization Name and Address

Consulpav International
P.O. Box 700
Oak View, California

10. Work Unit No. (TRAIS)

11. Contract or Grant No.


12. Sponsoring Agency's Name and Address

Office of Infrastructure R&D
Federal Highway Administration
6300 Georgetown Pike
McLean, VA 22101-2296

13. Type of Report and Period Covered

October 1998 - November 1999

14. Sponsoring Agency's Code

15. Supplementary Notes

Contracting Officer’s Technical Representative (COTR): Monte Symons, HRDI-13.

16. Abstract

This study focuses on the quality of the pavement temperature data in the Long-Term Pavement Performance (LTPP) program. Reliable pavement temperature data are necessary in the research planned for the LTPP program. Pavement surface temperature measurements and in-depth pavement temperature measurements have been recorded since the beginning of the LTPP program. Until this study, these data have been subject to only broad checks established for individual fields; no additional quality checks were made. The LTPP database is now undergoing various quality investigations focusing on comparisons of the data from two independent sources—infrared surface temperature measurements that were recorded automatically and in-depth temperature measurements that were made manually. The comparative processes identified various data errors and errors in associated data elements such as the time measurement. Examples of such errors include data entry errors such as transposition of numbers and errors in the tens-place entries. Missing data, malfunctioning infrared sensors, and time-recording errors such as errors with time zone changes or daylight savings time changes were identified. All identified pavement temperature errors were submitted for further evaluation, which could lead to either corrections or removal of erroneous data from the LTPP database.

17. Key Words

Infrared temperature, pavement temperature, BELLS, FWD, falling weight deflectometer, LTPP, Long-Term Pavement Performance, temperature errors.

18. Distribution Statement

No restrictions. This document is available to the public through the National Technical Information Service, Springfield, VA 22161.

19. Security Classif. (of this report)


20. Security Classif. (of this page)


21. No. of Pages


22. Price

Form DOT F 1700.7 (8-72) Reproduction of completed page authorized


SI (Modern Metric) Conversion Factors

Table of Contents





  1. Figure 1. Equation. Converting millivolts to temperature
  2. Figure 2. Equation. Calculate default IR values to derive IR sensor output in millivolts
  3. Figure 3. Graph. Infrared and manual temperatures for SN 8002-129
  4. Figure 4. Equation. Relationships in Tables 1 and 2.
  5. Figure 5. Equation. Rewritten Figure 4 equation to replace IR term
  6. Figure 6. Using conversion equation to rewrite equation
  7. Figure 7. Graph. Example of time plot of temperatures
  8. Figure 8. Graph. Example of an IR sensor ceasing to function
  9. Figure 9. Graph. Time-temperature plot showing computer time error
  10. Figure 10.Graph. Time-temperature plot showing 12-hour computer time error
  11. Figure 11. Graph. BELLS2 prediction for manual 1 temperatures using default IR data before cleaning
  12. Figure 12. Graph. Minimum detectable error possible by visual scan
  13. Figure 13. Graph. Manual 1 and BELLS2 compared (before data cleaning; all surfaces)
  14. Figure 14. Graph. Manual 3 and BELLS2 compared (before data cleaning, all surfaces)


  1. Table 1. Default calibration values for the two sensors used
  2. Table 2. Regression statistics for infrared versus manual temperatures from the North Atlantic Region
  3. Table 3. Regression statistics for infrared versus manual temperatures from the Western Region
  4. Table 4. Examples of invalid site data
  5. Table 5. FWD data without IR and manual temperature data
  6. Table 6. FWD data without IR and manual temperature data


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