Monday, August 21, 2017
2:00pm to 3:30pm ET
New Pavement Engineering Technologies: The Long Term Pavement Performance
Climate and Bind Tools
TRANSPORTATION RESEARCH BOARD
The Transportation Research Board has met the standards and requirements of
the Registered Continuing Education Providers Program. Credit earned on
completion of this program will be reported to RCEP. A certificate of completion
will be issued to participants that have registered and attended the entire session.
As such, it does not include content that may be deemed or construed to be an
approval or endorsement by RCEP.
Purpose Discuss new tools designed by the LTTP Program.
Learning Objectives At the end of this webinar, you will be able to: • Describe the LTPP Climate study and the lessons learned from the
effort. • Understand how the LTPP Climate tool functions and how to extract
data from the tool. • Describe the LTPP Bind study and the lessons learned from the effort. • Understand how the LTPP Bind program works and how to run an
analysis.
New Pavement Engineering Technologies - The Long Term Pavement Performance Climate and
Bind Tools
Larry Wiser, FHWA
Dr. Charles Schwartz, P.E., University of Maryland
Riaz Ahmad, iENGINEERING, Inc.
Jonathan Groeger, Amec Foster Wheeler
Transportation Research Board Webinar
2:00 PM – 3:30 PM
Monday, August 21, 2017
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Webinar Outline PART 1: Introduction
PART 2: The LTPP Climate Study
PART 3: Demo of LTPP Climate Tool
PART 4: The LTPP Bind Study
PART 5: Demo of LTPPBind Online
Q&A
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PART 1: Introduction
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The LTPP Program The Long Term Pavement Performance (LTPP)
program began in 1987 as part of the Strategic Highway Research Program (SHRP)
The longest running highway research program in history
$200+ Million study
Over 2,500 pavement test sections
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LTPP Program
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Climate Study The LTPP program has performed pioneering
work in climate data collection and analysis
Improvements in these data were needed to support current and future research
Began as a research study in 2011 to evaluate LTPP’s existing climate data and recommend improvements
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Climate Study MERRA was discovered as part of this research
Shifted purpose of the study to evaluate this new data source
Comparisons of MERRA vs. Automated Weather Station (AWS) and operating weather station (OWS) weather data statistics
Sensitivity of Mechanistic Empirical Pavement Design Guide (MEPDG) performance predictions to fundamental climate parameters
Comparison of MEPDG distress predictions using MERRA vs. AWS/OWS weather data
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MERRA Data MERRA: Modern-Era Retrospective Analysis for Research and Applications
• MERRA is a NASA reanalysis for the satellite era using a major new version of the Goddard Earth Observing System Data Assimilation System
• Reanalysis is a scientific method for developing a comprehensive record of how weather and climate are changing over time
http://www.fhwa.dot.gov/publications/research/infrastructure/pavements/ltpp/15019/15019.pdf
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MERRA Data • Long-term (1979-present) synthesis of climate data from
a suite of research satellite observations
• Continually updated with over 4 million global observations every 6 hours (with 2 week delay)
• A native 50km latitude by 50km longitude data grid
• Conducted at the NASA Center for Climate Simulation (NCCS) in Greenbelt, MD
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Benefits of MERRA • Denser, more uniform, and broader spatial
coverage
• Better temporal frequency and continuity
• Excellent data consistency and quality
• Focus on fundamental physical quantities
• Richer and more versatile data sets
• Automated updates to LTPP database
• Improvement over time
• Hourly data
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LTPP Climate Tool • Provides convenient dissemination
of NASA’s MERRA climatic data for infrastructure engineering applications in customary engineering units
• Intended users - pavement and bridge infrastructure engineers
• Ability to output climatic data set suitable for use with AASHTO Pavement ME Design software
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LTPPBind Online
A web-based tool integrated into LTPP InfoPaveTM for performance grade asphalt binder calculation.
The asphalt binder PG grade is selected based on pavement temperature along with maximum rut depth, desired level of risk, level of traffic loading and speed.
This tool will allow use of climatic data from MERRA, LTPP CLM, and user input.
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LTPPBind Online
The Multiple Stress Creep Recovery (MSCR) testing and concept are implemented to account for the extensive use of modified asphalt binders.
Same as LTPPBind 3.1, asphalt binders are selected incorporating the integrated climatic model, asphalt stiffness and MEPDG rutting concepts.
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LTPPBind Online
General Project Information
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LTPP InfoPave
https://infopave.fhwa.dot.gov/
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PART 2: LTPP Climate Study
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MEPDG Environmental Effects
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MERRA “Modern Era Retrospective-Analysis for Research and Applications”
Merger of physical modeling with satellite, airborne, ship, radiosonde, buoy, other physical measurements
>4 million observations utilized every 6 hours
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Sensitivity: Flexible Pavements
AC, Total Rutting most sensitive distresses (outputs) Annual temperature, temperature range most impactful inputs
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Sensitivity: Rigid Pavements
Slab cracking most sensitive distress (output) Multiple impactful inputs
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MERRA Data Global coverage
~55 km by 60 km horizontal spatial resolution at mid-latitudes
Continuous hourly temporal resolution since 1979
Sophisticated QC/QA of data
Provides hourly weather data required for Pavement ME Design: Air temperature Wind speed Percent sunshine Precipitation Humidity
http://www.fhwa.dot.gov/publications/research/ infrastructure/pavements/ltpp/15019/15019.pdf
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MERRA-1 vs. MERRA-2
MERRA-1 discontinued by NASA; superseded by MERRA-2
Improvements in MERRA-2 Improved modeling (e.g., precipitation) Enhanced data assimilation Slightly better horizontal resolution: ~50 km by 50 km Continues data series to present
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MERRA vs. ASOS Coverage
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MERRA vs. MEPDG Temperature: Typical Short Term Comparison
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Green = Collocated (<0.5 degree) MERRA+MEPDG data (20 combinations examined)
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HMA Distresses
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HMA Distresses
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JPCP Distresses
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Roughness
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Benefits of MERRA Physics-based fundamental modeling with massive data
assimilation
Closer, more uniform, global spatial coverage
Better temporal frequency and continuity
Better data consistency and quality
Focuses on physically realistic quantities
Rich and versatile data set
Will improve over time
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LTPP Climate Tool • Objective of LTPP Climate Tool is to provide convenient
dissemination of NASA’s MERRA climatic data for infrastructure engineering applications in customary engineering units
• Intended users - pavement and bridge infrastructure engineers
• Ability to output climatic data set suitable for use with AASHTO Pavement ME Design software
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• Data Attributes • Temperature • Precipitation • Humidity • Wind • Solar
• Data Frequency • Hourly • Daily • Monthly • Annually
Available Data
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• Temperature • Temperature • Soil temperature
layers 1 – 6 • Soil temperature
unsaturated zone • Soil temperature
saturated zone
• Precipitation • Precipitation • Evaporation • Infiltration • Overland runoff • Snow Mass • Snow Melt • Snow-covered area
fraction • Snowfall
Temperature and Precipitation Elements
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• Humidity • Specific humidity • Relative humidity • Air pressure
• Wind • North wind • East wind • Wind velocity • Air density
• Solar • Shortwave surface • Shortwave top of
atmosphere • Cloud cover • Percent sunshine • Emissivity • Albedo
Humidity, Wind and Solar Elements
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PART 3: Demo of LTPP Climate Tool
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http://infopave.fhwa.dot.gov
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LTPP Climate Tool
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LTPP Climate Tool
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Location Selection
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Area Selection
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LTPP Section Selection
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LTPP Climate Tool – Country
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LTPP Climate Tool – Map
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LTPP Climate Tool - Data
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LTPP Climate Tool – Graph
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Data Download Formats Tabulated Data – Microsoft Excel (XLS), Microsoft
Access (MDB), and Microsoft SQL Server (BAK).
Program Input – Integrated Climate Model (ICM) and Hourly Climatic Database (HCD) files. MERRA Climate Data for MEPDG Inputs Tool
Map – ESRI Shape File (SHP), and Keyhole Markup Language (KML) XML files.
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PART 4: The LTPP Bind Study
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LTPPBind Online A web-based tool integrated into LTPP InfoPaveTM.
PG grade based on pavement temperature, rut depth, reliability, traffic magnitude and speed (same as LTPPBind 3.1).
Compare PGs between AASHTO M320-10 and AASHTO M332-14 standards.
Uses climatic data from MERRA, LTPP CLM, and user input.
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Low Temperature PG Selection
TL,pav = Low asphalt concrete pavement temperature at surface, ºC Tair = Low air temperature, ºC Lat = Latitude of the section, degrees H = Depth to surface, mm σ2
Tair = Standard deviation of the mean low air temperature, ºC Z = Standard normal distribution value 2.055 for 98 percent reliability
Based on LTPP Seasonal Monitoring Program (SMP):
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High Temperature PG Selection Using Rutting Damage Model
PGH,d = PG damage at a rut depth DD = Average Yearly Degree-Days Air Temp. Over 10 ºC, x1000ºC RD = Rut depth (5–13 mm)
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Estimate PG Variability
CVPG = Yearly PG coefficient of variation, percent
Minimal effect for latitudes less than 20o or rut depths less than 7.632 mm.
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Adjust PG for Reliability
PGH,rel = PG at a reliability level Z, ºC DD = Average Yearly Degree-Days Air Temp. Over 10ºC, x1000
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PG Bumping for Heavy Traffic Adjustment Factor Adj
PGn = PGs + Adj Adj = PG adjustments for a site PGn = PG at a specific traffic loading and speed PGs = PG at standard loading (3 million axles) and high speed
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PG Designation for Traffic AASHTO M332-14 Standard
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PART 5: LTPP Bind Tool Demo
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LTPPBind Online
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LTPPBine Online
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LTPPBind Online
General Project Information
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LTPPBind Online
LTPPBind PG Calculator Help?
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General Project Information
Project Number: PRJ-003Project Title: PG Binder Selection 003Project Description:
Project Location
Project Location
Latitude, Degree:Longitude, Degree:Elevation, m:
Climatic Data
Lowest Yearly Air Temperature, Degree C:Lowest Air Temperature Standard Deviation:Yearly Degree Days > 10 Degree C:
Temperature Adjustments
Base High Temperature PG:Desired Reliability, %:Depth of Layer, mm:
Traffic Adjustments
Traffic Loading, ESAL:Traffic Speed:
Performance Grade
Performance Grade Temperature at 50% Reliability:Performance Grade Temperature at Desired Reliability:Adjustments for Traffic:
Latitude, Degree:
Longitude, Degree:
Elevation, m:
NextPrevious
Tools
MEPDG Inputs
Rigid Pavement Design
WIM Cost Analysis
LTPP Dynamic Modulus Prediction
Pavement Performance Forecast
FWD Calibration
LTPP Bind
Distress Identification Manual
Pavement Loading User Guide
LTPP InfoPave Mobile
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Select Location
Select Location
Please select location from the map or type the address in the search bar below:
CancelSelect
Selected Location
Latitude: 32.4709519
Longitude: -100.40593
Address: Nolan, TX 79556, United States
Please select Data Source from the options below:
MERRA Data LTPP CLM DataData Source:
Location Selection
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LTPPBind Online
LTPP VWS Data Selection
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LTPPBind Online
Climatic Data Calculation Steps 4, 5, & 6
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LTPPBind Online
Performance-Graded Asphalt Binder
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Questions and Answers
Today’s Participants
• Jonathan Groeger, Amec Foster Wheeler, [email protected]
• Larry Wiser, Federal Highway Administration, [email protected]
• Charles Schwartz, PhD, University of Maryland, [email protected]
• Riaz Ahmad, iENGINEERING Corporation, [email protected]
FHWA LTPP Publications
• Evaluation of LTPP Climatic Data Report • Evaluation of LTPP Climatic Data Tech Brief • LTPP Climate Tool Product Brief • LTPP Bind Online Product Brief
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