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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HOME SEARCH MAP DATA ANALYSIS VISUALIZATION TOOLS LIBRARY HELP MY LTPP NON-LTPPTOOLS

: Tools

Start Projects Reports Help

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, jonathan.groeger@amecfw.com

• Larry Wiser, Federal Highway Administration, larry.wiser@dot.gov

• Charles Schwartz, PhD, University of Maryland, schwartz@umd.edu

• Riaz Ahmad, iENGINEERING Corporation, rahmad@iengineering.com

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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