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

Thursday, April 19, 2012

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 -

Thursday, April 19, 2012

Fundamental Engineering

Climate Inputs

EICM

Material Properties

Transfer Functions

Predicted Performance Mechanistic Analysis

Traffic

Thursday, April 19, 2012

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

Thursday, April 19, 2012

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.

Thursday, April 19, 2012

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

– Various Unnamed Sources

DARWin-ME

Thursday, April 19, 2012

Climate Data

Thursday, April 19, 2012

Climate Data

Thursday, April 19, 2012

Thursday, April 19, 2012

Climate Data – More Intuitive

Thursday, April 19, 2012

Traffic Data

Continuous Length ClassificationContinuous Axle Classification

Weigh-in-Motion Station

Thursday, April 19, 2012

Class 9 TrucksClass 5 Trucks

18k ESAL’s

Thursday, April 19, 2012

Class 9 TrucksClass 5 Trucks

Axle Load Spectra

Thursday, April 19, 2012

Traffic Data

WIM Data

Thursday, April 19, 2012

Traffic Data

6-14

Thursday, April 19, 2012

Traffic Data – Ability to Import from XML Database

MEPDG User

Thursday, April 19, 2012

Loads and Layer Stiffness

E*

Mr

Mr

σ

Thursday, April 19, 2012

Loads and Layer Stiffness

Mechanistic AnalysisLayered Elastic Analysis

E*

Mr

Mr

σ

Thursday, April 19, 2012

Loads and Layer Stiffness

Mechanistic AnalysisLayered Elastic Analysis

E*

Mr

Mr

σ

Strain Calculations at Critical Locations

E = σ/ε

Thursday, April 19, 2012

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

Thursday, April 19, 2012

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

Thursday, April 19, 2012

6-19

M-E Guide Outputs: Flexible

Fatigue Cracking

Thermal Cracking

IRIRut Depth

Thursday, April 19, 2012

User Friendly Software

Thursday, April 19, 2012

User Friendly Software

Thursday, April 19, 2012

Climate and Materials

Time, years

Thursday, April 19, 2012

Climate and Materials

Time, years

AC Modulus

Thursday, April 19, 2012

Climate and Materials

Time, years

Subgrade Modulus

AC Modulus

Thursday, April 19, 2012

Climate and Materials

Time, years

Traffic

Subgrade Modulus

AC Modulus

Thursday, April 19, 2012

Climate and Materials

Time, years

Each load application

Traffic

Subgrade Modulus

AC Modulus

Thursday, April 19, 2012

Thursday, April 19, 2012

First Impressions

Thursday, April 19, 2012

Communicative between Screens

Thursday, April 19, 2012

Instinctive Operations

Thursday, April 19, 2012

Itemized Data Export Capability

Thursday, April 19, 2012

Run-Time Performance

Thursday, April 19, 2012

Open and analyze more than one project

Thursday, April 19, 2012

Exploring Sensitivity

Thursday, April 19, 2012

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

Thursday, April 19, 2012

Thursday, April 19, 2012

31

Thursday, April 19, 2012

32

Thursday, April 19, 2012

32

DARWin-ME is coming to a computer near youSummer 2012

Thursday, April 19, 2012

Conclusions

Very intuitive, a real pavement analysis tool

Run faster and multiple projects Use your imagination to consider

pavements

Thursday, April 19, 2012

34

Thank you

Thursday, April 19, 2012