pavement design using mepdg darwin-me

Pavement Design Using MEPDG DARWin-ME

Jay Goldbaum, P.E., Colorado DOT

39th AnnualRocky Mountain Asphalt Conference

and Equipment ShowFebruary 24th, 2012

Thursday, April 19, 2012

Overview

Why use the Mechanistic Empirical Pavement Design Guide (MEPDG)?

Goal of DARWin-ME Features

– Climate– Traffic Data– Material Properties

Software Comparison Example Conclusions


Why Mechanistic Empirical ?

Based on fundamental engineering principles Climate linked to design and materials Enhanced definition of material properties

– Ability to relate material properties to performance Improved traffic characterization Excellent pavement forensic tool Modular system that allows for incremental

enhancement Ability to design and calibrate for local

conditions- Relates to all ME Procedures -


Fundamental Engineering

Climate Inputs

EICM

Material Properties

Transfer Functions

Predicted Performance Mechanistic Analysis

Traffic


Comparison between the old and the new

Factors 1993 AASHTO

MEPDGDARWin-ME

Simple/Less Costly

Diversity of Conditions

Colorado Calibration; Roadway Segments

Accuracy of Method

Climatic Effects

Material Properties - Site

Time Effects on Properties


DARWin-ME Goal:

Provide the transportation community with a production level, state-of-the-art software tool for the analysis of new and rehabilitated pavement structures consistent with AASHTO’s Mechanistic Empirical Pavement Design Guide.


“The MEPDG is an analysis tool, not a pavement design program.”

– Various Unnamed Sources

DARWin-ME


Climate Data


Climate Data – More Intuitive


Traffic Data

Continuous Length ClassificationContinuous Axle Classification

Weigh-in-Motion Station


Class 9 TrucksClass 5 Trucks

18k ESAL’s


Class 9 TrucksClass 5 Trucks

Axle Load Spectra


Traffic Data

WIM Data


Traffic Data

6-14


Traffic Data – Ability to Import from XML Database

MEPDG User


Loads and Layer Stiffness

E*

Mr

Mr

σ



Mechanistic AnalysisLayered Elastic Analysis

E*

Mr

Mr

σ



Mechanistic AnalysisLayered Elastic Analysis

E*

Mr

Mr

σ

Strain Calculations at Critical Locations

E = σ/ε


6-17

0

750,000

1,500,000

2,250,000

3,000,000

0 6 12 18 24 30 36 42 48 54 60

Mod

ulus

(psi

)

Pavement Age (month)

SMA

Grading SX


Material PropertyInput LevelInput LevelInput Level

Material Property1 2 3

HMA Dynamic Modulus - -HMA Repeated Load Permanent Deformation

HMA Indirect Tensile Creep Compliance -HMA Indirect Tensile Strength -HMA Maximum Specific Gravity

Bulk Specific Gravity of Cores

HMA Mixture Design Sheets -

Asphalt Specific Gravity

Asphalt Content of HMA Mixture

Asphalt Performance Grade

Asphalt Penetration @ 25 °C - -Asphalt Viscosity @ 140 °C - -Asphalt Viscosity @ 275 °C - -Asphalt Viscosity - -Asphalt Softening Point - -Fine aggregate specific gravity & absorption

Coarse aggregate specific gravity & absorption

Sieve analysis of fine & coarse aggregate -

HMA Material Properties Required for DARWin-ME


6-19

M-E Guide Outputs: Flexible

Fatigue Cracking

Thermal Cracking

IRIRut Depth


User Friendly Software


Climate and Materials

Time, years



Time, years

AC Modulus



Time, years

Subgrade Modulus

AC Modulus



Time, years

Traffic

Subgrade Modulus

AC Modulus



Time, years

Each load application

Traffic

Subgrade Modulus

AC Modulus


First Impressions


Communicative between Screens


Instinctive Operations


Itemized Data Export Capability


Run-Time Performance


Open and analyze more than one project


Exploring Sensitivity


Comparison of CDOT and DARWin-ME new HMA design

Factor CDOT DARWin-MEDesign ESALs 18 million 18 millionReliability 95% 95%Subgrade R-value (MR)

9 (3448 psi) 9 (6098 psi)Aggregate Base Thickness

24-in 24-in

Aggregate Base MR

31,826 psi(Struc. Coefficient = 0.12)

21,500 psi

HMA Thickness

9-in 9-in** Passed all criteria except for rutting


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32


32

DARWin-ME is coming to a computer near youSummer 2012


Conclusions

Very intuitive, a real pavement analysis tool

Run faster and multiple projects Use your imagination to consider

pavements


34

Thank you


pavement design using mepdg darwin-me

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