|Project Name:||Evaluation of Long-Term Pavement Performance Program Climatic Data for Use in Mechanistic-Empirical Pavement Design Guide Calibration and Other Pavement Analyses|
Office of Infrastructure Research and Development |
|Team:||Long-Term Pavement Performance Team|
Infrastructure Research and Technology Strategic Plan and Roadmap|
|Project Description:||The current Climate (CLM) module of the Long-Term Pavement Performance (LTPP) database began as the Environment (ENV) module in 1992, with major revisions and enhancements performed in 1998. Since 1998, pavement technology and the use of climatic data have evolved (with adoption of the Integrated Climatic Model in the Mechanistic-Empirical Pavement Design Guide (MEPDG), for example), and there is a need for a reassessment of climatic data in general, and the sufficiency of LTPP climatic data collection specifically. During the last climate data update performed by the LTPP program in 2008, a need has developed to create a time series-based operating weather stations (OWS) selection strategy. The reason for this is over the 20 years of the LTPP program, new weather stations have been added, others are no longer operational, and the locations of exiting weather stations have changed, although their station identification remained the same. There is a need to develop a methodology to treat estimates of location-specific climate data from surrounding weather stations whose locations and characteristics change over time. There is also a need to develop an estimate of variability or uncertainty in climate estimates derived from the averaging process of nearby weather stations. The National Cooperative Highway Research Program (NCHRP) 1-34D study on pavement drainage found a better correlation between the Thornthwaite Moisture Index (TMI), which is a climate-soil moisture holding potential interaction parameter, than traditional precipitation-based climate indices. The LTPP Automated Weather Station monitoring measurements have been terminated; however, no assessment of the value of the solar radiation data collected by this study have ever been made against other data sources, nor has the use of solar radiation data from other data sources for more widespread inclusion in the LTPP program been assessed. It is not yet known how issues, if any, associated with “global warming” caused by increases in solar output, a decrease in the ability of the earth’s atmosphere to reflect this radiation, or a combination of these effects, will affect the service life of pavement materials being used today.|
|Start Date:||May 18, 2011|
|End Date:||January 17, 2015|
The key project objective is to develop guidance for implementing climatic data for use in Mechanistic-Empirical Pavement Design Guide (MEPDG) calibration and other pavement analyses.
|Test Methodology:||Identify anomalies that persist and advance the use of climate data in infrastructure engineering applications.|
|Other Information:||LTPP Analysis Plan | Objective 3 | Outcome A | Priority Critical | Sequence 2|
|Expected Benefits:||Climate data is a fundamental input to pavement engineering research and practical applications. A great deal of groundbreaking work has been performed by Long-Term Pavement Performance to characterize and summarize climatic data for test sections. Lessons learned and improvements to climatic data collection are needed to support other fundamental research for pavement design, pavement performance, and to evaluate climatic change effects on pavements. The payoff potential is large, as this study has broad applications to the science of pavement engineering and future pavement performance studies conducted by all highway agencies.|
|Deliverables:||1. Name: Final report.|
Product Type(s): Research report, Data, Techbrief
Description: The deliverable is a final report documenting the research approach, key findings, lessons learned from the Long-Term Pavement Performance (LTPP) climatic program, recommendations, and implications.
2. Name: Stand-alone guide.
Product Type(s): Research report, Draft standard, specifications, or guidelines
Description: A guide shall be written for use by pavement practitioners to determine climatic data elements necessary for a variety of common pavement engineering analyses, including sources for obtaining climatic data based on lessons learned from the Long-Term Pavement Performance (LTPP) program. The guide should provide recommendations regarding the collection, analysis, and reporting of climatic data elements including recommendations as to best practices to combine existing climate stations to determine a point specific climate for use in analysis.