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| REPORT |
| This report is an archived publication and may contain dated technical, contact, and link information |
 |
| Publication Number: FHWA-HRT-17-049 Date: October 2017 |
Publication Number: FHWA-HRT-17-049 Date: October 2017 |
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Previous studies have been performed to investigate roughness development in pavements. The Long-Term Pavement Performance (LTPP) Program has been collecting longitudinal profile data for the two wheelpaths and the center of the lane using an inertial profiler for over 20 years. The goal of this study was to evaluate the changes in roughness as measured by the International Roughness Index (IRI) along the center of the lane at Specific Pavement Studies 1 (structural factors for flexible pavement) sections over time and identify environmental and subgrade parameters that contribute to the increase in roughness. This information can be used to improve pavement design procedures and further develop models for predicting the change in roughness due to environmental conditions. The study shows it is very important to provide drainage for pavements built over fine-grained subgrade in the wet-freeze zone to reduce the rate of change of roughness. This study also compared the changes in roughness using the computed IRI along the center of the lane with the changes in mean IRI (i.e., average IRI of the left and the right wheelpaths). The intended audiences for this report are pavement engineers and researchers.
Cheryl Allen Richter, Ph.D., P.E.
Director, Office of Infrastructure
Research and Development
Notice
This document is disseminated under the sponsorship of the U.S. Department of Transportation (USDOT) in the interest of information exchange. The U.S. Government assumes no liability for the use of the information contained in this document. This report does not constitute a standard, specification, or regulation.
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Technical Report Documentation Page
| 1. Report No.
FHWA-HRT-17-049 |
2. Government Accession No. | 3 Recipient's Catalog No. | ||
| 4. Title and Subtitle
Investigation of Increase in Roughness Due to Environmental Factors in Flexible Pavements Using Profile Data from Long-Term Pavement Performance Specific Pavement Studies 1 Experiment |
5. Report Date October 2017 |
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| 6. Performing Organization Code | ||||
| 7. Author(s)
R.W. Perera and A. Al-Rawashdeh |
8. Performing Organization Report No.
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9. Performing Organization Name and Address SME |
10. Work Unit No. (TRAIS) |
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| 11. Contract or Grant No.
DTFH61-14-C-00021 |
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| 12. Sponsoring Agency Name and Address
Federal Highway Administration |
13. Type of Report and Period Covered
Covered |
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14. Sponsoring Agency Code
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| 15. Supplementary Notes
The Contracting Officer’s Technical Representative (COTR) was Larry Wiser, HRDI-30. |
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| 16. Abstract
From the start of the Long-Term Pavement Performance (LTPP) Program, the longitudinal profiles along the two wheelpaths at test sections have been collected using an inertial profiler. In December 1996, starting with the K.J. Law T-6600 inertial profiler, all profilers used in the LTPP Program have collected profile data along the center of the lane in addition to collecting data along the two wheelpaths. The change in the profile along the center of the lane in flexible pavements was expected to be affected mainly by environmental effects. The goal of this project was to evaluate the changes in the International Roughness Index (IRI) along the center of the lane at Specific Pavement Studies 1 test sections over time and identify environmental and subgrade parameters that contribute to an increase in IRI along the center of the lane. The following activities were performed for this project: (1) analyze the center of the lane IRI (CLIRI) and mean IRI (MIRI) (i.e., average IRI of the left and the right wheelpaths) at test sections to evaluate changes over time, (2) compare the change in IRI for the center of the lane with the change in MIRI at the test sections, (3) identify subgrade and environmental parameters that contribute to an increase in IRI along the center of the lane, (4) perform a detailed evaluation to identify how the CLIRI changes for a select group of test sections, and (5) develop models to predict the change in CLIRI at the test sections. |
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| 17. Key Words
IRI, LTPP, long-term pavement performance, pavement smoothness, pavement roughness. |
18. Distribution Statement
No restrictions. This document is available through the National Technical Information Service, Springfield, VA 22161. |
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19. Security Classification Unclassified |
20. Security Classification Unclassified |
21. No. of Pages 193 |
22. Price | |
| Form DOT F 1700.7 (8-72) | Reproduction of completed page authorized |
SI* (Modern Metric) Conversion Factors
| AASHTO | American Association of State Highway and Transportation Officials | |
| AC | asphalt concrete | |
| AIMS | Ancillary Information Management System | |
| ATB | asphalt-treated base | |
| CLIRI | center of the lane IRI | |
| DF | dry-freeze | |
| DNF | dry no-freeze | |
| DGAB | dense graded aggregate base | |
| ERD | Engineering Research Division | |
| ESAL | equivalent single axle load | |
| FI | freezing index | |
| FHWA | Federal Highway Administration | |
| GPS | General Pavement Studies | |
| ICC | International Cybernetics Corporation | |
| IQD | interquartile distance | |
| IRI | International Roughness Index | |
| KESAL | 1,000 equivalent single axle loads | |
| LTPP | Long-Term Pavement Performance | |
| MEPDG | Mechanistic-Empirical Pavement Design Guide | |
| MIRI | mean IRI | |
| PATB | permeable asphalt-treated base | |
| PI | Plasticity Index | |
| PPDB | Pavement Performance Database | |
| PSD | power spectral density | |
| RMS | root mean square | |
| SDR | Standard Data Release | |
| SF | site factor | |
| SMP | seasonal monitoring program | |
| SN | structural number | |
| SPS | Specific Pavement Studies | |
| WF | wet-freeze | |
| WNF | wet no-freeze |
