Reformulated Pavement Remaining Service Life Framework

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FOREWORD

Many important decisions are necessary in order to successfully provide and manage a pavement network. At the heart of this process is the prediction of needed future construction events. One approach to providing a single numeric on the condition of a pavement network is the use of pavement remaining service life (RSL). However, many issues exist with the current RSL terminology and resulting numeric that complicate proper interpretation, interagency data exchange, and use. A major source of uncertainty in the current RSL definition is the use of the term "life" to represent multiple points in the pavement construction history. The recommended path to consistency involves adopting terminology of time remaining until a defined construction treatment is required (i.e., RSL is replaced by remaining service interval (RSI)). The term "RSI" has the ability to unify the outcome of different approaches to determine needs by focusing on when and what treatments are needed and the service interruption created. This report presents the framework for replacing the current RSL terminology with one based on more exact construction event terms. It provides detailed information on the research performed concerning remaining pavement life. It explores many issues that exist with the current RSL terminology that complicate proper interpretation, interagency data exchange, and use. While this report focuses on pavements, it is also applicable to other types of transportation infrastructure. A companion document provides step-by-step guidelines for implementing the RSI terminology.⁽¹⁾ This report is intended for use by pavement managers and pavement investment decisionmakers across the United States.

Jorge E. Pagán-Ortiz
Director, Office of Infrastructure
Research and Development

Technical Report Documentation Page

SI* (Modern Metric) Conversion Factors

TABLE OF CONTENTS

EXECUTIVE SUMMARY

Chapter 1. Introduction

• Introduction
• Pavement Business Decisions
• Role of RSL In Pavement Business Decisions
• Issues with Current RSL Terminology
• Framework Presented In This Report

Chapter 2. Refocus of Pavement Remaining Life Vocabulary

• Reformulating RSL Terminology
• Fundamental Pavement Planning Elements
• Construction Event Terminology

Chapter 3. Future Construction Needs Analysis Framework

• Introduction
• Construction Triggers
• Threshold Limits
• Performance Curves
• Collection of Inputs
• Strategy Selection
• Assessment and Update

Chapter 4. Construction Triggers

• Introduction
• Level of Service
• Pavement Surface Distress
• Structural Considerations
• Safety
• Agency Time-Based Rules
• Traffic Capacity

Chapter 5. Threshold Limits

• Introduction
• Subjective Threshold Limits
• Engineering Considerations
• Empirical Methods
• Economic Analysis
• Combination of Approaches

Chapter 6. Performance Curves

• Introduction
• Models Based on Design Equations
• Empirical Models
• Agency Time-Based Rules
  
  

Chapter 7. Collection of Inputs

• Introduction
• Pavement Roughness
• Pavement Distress
• Pavement Structural Response
• Traffic Loads
• Climate
• Missing Data
• Measurement Variability
• Sampling Intervals and Frequency

Chapter 8. Strategy Selection

• Introduction
• Network Analysis
• Project Analysis

Chapter 9. Assessment and Update

• Introduction
• Assessments
• Updates

Chapter 10. Summary

Appendix A. Pavement Design and Management Concepts

• Pavement Design Basics
• Staged Construction and Perpetual Pavements
• Multiple Distress-Based Pavement Design
• Rehabilitation and Reconstruction Design
• Pavement Economics
• Summary

Appendix B. Pavement RSL Prediction Models

• Introduction
• Categorization of RSL Models
• Life Table Survivor Curves
• Kaplan-Meier Survival Analysis
• Failure Time Theory
• Cox PH Model
• 1986 and 1993 AASHTO Pavement Design Guides
• HPMS/HERS Models
• Other Contemporary Pavement RSL Models
• National Cooperative Highway Research Program (NCHRP)
• Friction
• Noise
• Concepts From Outside the Pavement Industry
• Literature Review Observations
  
  

References

Bibliography

List of Figures

List of Tables

List of Abbreviations

EXECUTIVE SUMMARY

The remaining service life (RSL) concept has been around for decades and is well entrenched in the pavement community. It is used at all levels of the pavement management decision process to plan for future field construction events. However, there is no single, clear, widely accepted definition of RSL. Moreover, there is a great deal of uncertainty associated with the definition, especially with the use of the term "life" to represent different points in a pavement's construction history In addition, "life" is interpreted differently by stakeholders.

To overcome the RSL shortcomings, this framework introduces terminology that removes the word "life" from the lexicon since it is the basis for confusion. Instead, the new terminology, known as the remaining service interval (RSI) introduces the concept of time remaining until a defined construction event is required. Pavements are comprised of interrelated structural parts that can be maintained, preserved, restored, rehabilitated, or reconstructed to serve the intended transportation needs.

The RSI concept does not provide an alternative to assessing the health of the network or making decisions about where to spend the available funds. It simply provides a clear terminology and a logical process that will create a consistent construction event-based terminology and understanding (i.e., types of construction events and the timing of those events within the concept of life-cycle cost (LCC), risk analyses, and other prioritization approaches based on streams of future construction events and benefits to facility users).