Asset Management

Performance Evaluation of Various Rehabilitation and Preservation Treatments

Final - January 6, 2010

U.S. Department of Transportation Federal Highway Administration
Office of Asset Management HIAM-1 Washington DC 20590-0001

FHWA-HIF-10-020

TABLE OF CONTENTS

EXECUTIVE SUMMARY

CHAPTER 1. INTRODUCTION

• Background
• Objectives and Scope
• Report Organization

CHAPTER 2. INVENTORY AND PERFORMANCE DATA COLLECTION

• Selection of Target States
• Data Collection Method

CHAPTER 3. TREATMENT PERFORMANCE

• Overview
• Observations

CHAPTER 4. CONCLUSIONS AND RECOMMENDATIONS

• Conclusions
• Recommendations

LIST OF FIGURES:
Figure 1. Diagram of target states and LTPP climatic zone
Figure 2. Number of states responding and number of projects identified

LIST OF TABLES:
Table 1. List of PM and rehabilitation strategies and data collection items
Table 2. Identified issues with literature-based data collection
Table 3. State contact title for treatment performance data collection
Table 4. Data input worksheet column definitions
Table 5. Target States and submitted treatment performance data
Table 6. HMA - HMA thin overlay summary
Table 7. HMA - chip seal summary
Table 8. HMA - microsurfacing summary
Table 9. HMA - crack sealing summary
Table 10. HMA - mill and resurfacing summary
Table 11. HMA - hot in-place recycling summary
Table 12. HMA - slurry seal summary
Table 13. HMA - fog seal summary
Table 14. HMA - cold in-place recycling summary
Table 15. HMA - full depth reclamation summary
Table 16. HMA - structural overlay (mill & fill) summary
Table 17. HMA - whitetopping summary
Table 18. PCC - Diamond grinding summary

APPENDICES:
APPENDIX A - ACKNOWLEDGMENTS
APPENDIX B - PAVEMENT CONDITION RATING BY TARGET STATES
APPENDIX C - TREATMENT DATA
APPENDIX D - LIST OF TREATMENTS BY CLIMATIC ZONE
APPENDIX E - REFERENCES

FOREWORD

The pavement preservation philosophy has seen increased adoption in State Departments of Transportation (DOTs) across the United States as a result of the successful educational and outreach programs instituted by FHWA and other pavement preservation organizations over the past decade. The fact remains that the effectiveness of pavement preservation activities has not been well documented or publicized throughout the United States. Intuitively for pavement professionals the philosophy makes perfect sense, however, hard facts supporting this stance are still elusive except for anecdotal examples.

The objective of this study was to conduct a synthesis to highlight the degree to which pavement preservation treatments (including minor rehabilitation treatments) extend the service life of pavements with or without adding strength. This study was carried out by conducting a study of six target states that were known to perform, collectively, the totality of all treatments under consideration.

The results of this study are summarized in a series of tables documenting the data provided by the states. A summary of each treatment's performance is also contained in this report. A series of observations, conclusions, and recommendations are also included. The findings of this activity will be used to provide support for FHWA policy guidance related to pavement maintenance and minor rehabilitation, commonly referred to as pavement preservation.

Notice

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 the use of the information contained in this document.

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

Quality Assurance Statement

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

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

SI (Modern Metric) Conversion Factors

LIST OF ACRONYMS AND ABBREVIATIONS

• Acronym - Definition
• AADT - Annual average daily traffic
• AASHTO - American Association of State and Highway Transportation Officials
• DF - Dry-Freeze
• DNF - Dry-No Freeze
• DOT - Department of Transportation
• ESAL - Equivalent Single Axle Load
• FHWA - Federal Highway Administration
• HMA - Hot-Mix Asphalt
• HPMS - Highway Performance Monitoring System
• MMS - Maintenance Management System
• PCC - Portland Cement Concrete
• PCR - Pavement Condition Rating
• PM - Preventive Maintenance
• PMS - Pavement Management System
• RIP - Research in Progress
• TRIS - Transportation Research Information Service
• WF - Wet-Freeze
• WNF - Wet-No Freeze

EXECUTIVE SUMMARY

Pavement preservation has been defined by FHWA as, "a program employing a network level, long-term strategy that enhances pavement performance by using an integrated, cost-effective set of practices that extend pavement life, improve safety and meet motorist expectations." One of the critical features of a pavement preservation program is determination of the extended service life provided by each of the treatments employed by a State Department of Transportation (DOT). Determining this function for each treatment allows a comparison of treatment effectiveness and ultimately provides input into the final treatment selection process. The objective of this study was to conduct a synthesis to highlight the degree to which pavement preservation treatments (including minor rehabilitation treatments) extend the service life of pavements with or without adding strength. The work was carried out through an examination of current state practices and performance results in six "target" states. This study examined treatments for hot-mix asphalt and portland cement concrete pavements.

The process used by the team to capture data from the states included the following:

• A literature review to identify potential target states,
• Development of a standardized data collection input spreadsheet with definitions for each input parameter,
• Completion of the data collection template by the states¹, and
• Synthesis of the results and determination of representative values.

A total of 256 projects from six target States collectively covering the specific 20 treatment types were collected and these projects formed the basis for the performance evaluations in this study. Of the 256 projects submitted, seventy-one projects (28%) were subsequently not considered for further inclusion in the study due to a variety of factors, the most notable being the absence of extended service life information.

For the remaining projects, the data was summarized to yield the most common values for the following data items:

1. Timing of application - the stage of life (in years) the preventive and/or rehabilitative action was taken.
2. Annual average daily traffic and percentage of trucks on the pavement section associated with each treatment.
3. Distress types and values used to trigger each treatment.
4. Extended pavement service life or structural life associated with each treatment.
5. Cost/lane-mile associated with each treatment.

In summary, the extended service life ranges for each treatment are shown in the following.

¹It should be noted that this process was very intensive for the target states and their participation and response is highly appreciated

Through conduct of this study, the following conclusions were reached:

• Most of the target states use a number of preservation treatments and strategies. This was to be expected as the target states were pre-screened to yield as much data as possible on life extension of as many of the treatments as possible.
• It seems that it was very difficult for the states to extract the data needed for this study. For some States all of the data exists, but cannot be linked effectively and/or efficiently. In others States the data simply does not exist, or data has not been collected for a long enough period of time. Improvements to systems to collect and link traffic, condition, construction, and maintenance history are needed.

² The upper value (8) is based upon extended service life to-date.

• Pavement condition data (distress, ride, and rutting) are collected and summarized using different strategies across the States making it difficult to compare data between States.
• Within a particular State, the process for collecting and analyzing pavement performance data changes over time. These changes make it difficult to perform long-term studies of treatment performance and effectiveness.
• Many of the treatments, especially recycling treatments, are relatively new to many states (cold in-place recycling, full-depth reclamation, and hot in-place recycling) and the States (1) do not have much experience with these treatments, or (2) existing recycled sections have not been down long enough to assess the life extension.
• Because of the above stated limitations, it is very difficult to perform a comparison of the effectiveness of treatments across State DOTs.

Based on these conclusions, the study provides the following recommendations:

• The States should continue to be encouraged to use and quantify the performance and benefits of pavement preservation treatments.
• The States should continue to develop and implement integrated infrastructure management systems. A primary goal of these systems should be to make quantitative decisions on the use of cost effective treatments throughout the systems life cycle. In order to accomplish this, the systems should be able to link the treatment type, treatment date, treatment location, cost, previous construction history, and performance information over a long period of time. These systems should also attempt to identify why a particular treatment was used and the decision criteria used to touch a section of roadway.
• It should be realized that each State develops its pavement management system (PMS) to meet the business needs of the individual State. A State PMS is also dependent on the technology deployed by that State to collect their information. Individual State PMSs are not necessarily designed to foster comparison of one State's data with another, although that functionally would be useful from the Federal Highway Administration's (FHWA's) perspective. It is recommended that development and adoption of performance standards that can be used to compare pavement performance State-to-State be continued. The current re-development of the Highway Performance Monitoring System (HPMS) process is a good start in this regard. The AASHTO distress protocols are another good start. Use of uniform standards can provide information that can be used by all states to compare their pavement investment decision with neighboring States in order to make informed pavement treatment investment decisions. Minimum guidelines should be used so that each State can collect a set of uniform data (State-to-State) but still have the flexibility to manipulate the data to the condition score or analysis matrix to meet their individual State's needs.
• Research into methods and technology transfer in order to maintain temporal continuity for pavement performance data should be encouraged. By necessity, State DOTs change their performance data collection protocols, technology, and methods over time. When this occurs, a break occurs in the performance history of every pavement section. Performance over time cannot be easily determined. Therefore, treatment effectiveness determination can be compromised. Strategies to overcome this reality should be developed and implemented.
• Long-term monitoring of pavements in a consistent manner should be encouraged. Many States do not have adequate long term monitoring data with which to perform this study. In addition, some of the treatments are relatively new and time must pass before their long-term effectiveness can be determined.
• The various national and regional pavement preservation groups should continue to work with and educate the States in development of systems to collect data that will support determination of the cost effectiveness of preservation and rehabilitation treatments. Anecdotal data alone is not sufficient to convince agencies to use preservation treatments.
• System preservation has become a priority for many, if not all, State DOTs. As a result, the capability of tracking, storing and presenting various types of treatment performance data is critical to make effective conversions both within and outside of the organization, which essentially leads to a more accountable usage of limited budget and the best possible conditions for the funding levels available. In this regard, some of the keys for the State should include: maintain consistency in pavement management personnel and data quality; develop a strong, cooperative relationship with the software vendor; regularly promote pavement preservation concepts/benefits; build consensus for the pavement preservation; continue to improve PMS system with time.

The results of this study have provided insight into the extended service life of various treatments throughout six target states. Valuable lessons were learned in conducting a study of this type and these lessons should be carried forward to other studies that compare treatment performance between various State DOTs.