Key Findings From LTPP Analysis 2000-2003

INTRODUCTION

The Long-Term Pavement Performance (LTPP) program, established in 1987, is a comprehensive 20-year study of in-service pavements using a series of rigorous long-term field experiments to monitor more than 2,400 asphalt and portland cement concrete (PCC) pavement test sections across the United States and Canada. The program's primary goal is to understand why some pavements outperform others. Knowledge of the factors contributing to good pavement performance is key to building and maintaining a cost-effective highway system.

LTPP has addressed topics ranging from traffic loading to pavement design, maintenance, and rehabilitation. Findings illustrate not only the immediate value of the LTPP database, but also its potential for improving pavement technology.

This document highlights some key findings from LTPP analysis studies completed between 2000 and 2003. A number of analysis projects have been conducted since the publication of the first volume in 2000, Key Findings from LTPP Analysis 1990-1999. In all, approximately 50 documents were reviewed, including LTPP research reports and National Cooperative Highway Research Program (NCHRP) projects using LTPP data. Most of these documents are available at the LTPP or NCHRP Web site. The goal of this report is to provide LTPP partners with information that can help them in their efforts to design, build, and maintain cost-effective and long-lasting pavements, by providing sections on:

• Site conditions.
• Structural features.
• Material characterization.
• Initial roughness.
• Pavement maintenance.
• Pavement rehabilitation.
• Local calibration of the 2002 Pavement Design Guide.

The LTPP program incorporates two major studies­the Specific Pavement Studies (SPS) and the General Pavement Studies (GPS). The primary goal of SPS experiments is to conduct detailed analysis of specific performance factors of newly constructed pavements and overlays. In contrast, the primary goal of GPS experiments is to analyze performance factors of existing pavements and overlays.

LTPP Program

• SPS-1      Study of Structural Factors for Flexible Pavements
• SPS-2      Study of Structural Factors for Rigid Pavements
• SPS-3      Preventive Maintenance Effectiveness of Flexible Pavements
• SPS-4      Preventive Maintenance Effectiveness of Rigid Pavements
• SPS-5      Rehabilitation of Asphalt Concrete (AC) Pavements
• SPS-6      Rehabilitation of Jointed PCC Pavements
• SPS-7      Bonded PCC Overlays of Concrete Pavements
• SPS-8      Study of Environmental Effects in the Absence of Heavy Loads
• SPS-9      Validation of Superpave Asphalt Specifications and Mix Design

• GPS-1      AC on Granular Base
• GPS-2      AC on Bound Base
• GPS-3      Jointed Plain Concrete Pavements (JPCP)
• GPS-4      Jointed Reinforced Concrete Pavements (JRCP)
• GPS-5      Continuously Reinforced Concrete Pavements (CRCP)
• GPS-6A   Existing AC Overlays on AC Pavements
• GPS-6B   New AC Overlays on AC Pavements
• GPS-7A   Existing AC Overlays on PCC Pavements
• GPS-7B   New AC Overlays on PCC Pavements
• GPS-9      Unbound PCC Overlays of PCC Pavements

Table of Contents | Next