THE GERMAN EMPIRICAL–MECHANISTIC DESIGN SYSTEM PART … · 2016-02-09 · Fakultät...

Fakultät Bauingenieurwesen - Institut für Stadtbauwesen und Straßenbau - Professur für Straßenbau

THE GERMAN EMPIRICAL – MECHANISTICDESIGN SYSTEM

PART II - DESIGN APPROACH FOR THINSURFACED PAVEMENTS

Prof. Dr.-Ing. habil. Frohmut WellnerDr.-Ing. habil. Sabine Leischner

TU Dresden

NADim Seminar - Oslo 03.12.2015


Oslo, 3.12.2015 Folie 2

Two design processes for flexible pavements

• Empirical design chart – RStO

• M-E design procedure - RDO Asphalt


Oslo, 3.12.2015 Folie 3

German Design Charts RStO 12 Bk 0.3 <300,000 10-t-ESALs

Minimum thickness of the asphalt layers 10 cm also for LVR in Germany


Oslo, 3.12.2015 Folie 4

Thin asphalt surface up to 4 cm

Base course (High quality UGM)

Sub-base layer(Frost protection)

Subgrade

Introduction

LVR < 100.000 10-t-standard axles


Oslo, 3.12.2015 Folie 5

Vertical Stresses

Pavement structure with thick asphalt layer (220mm)

Pavement structure with thin asphalt layer (10mm)


Oslo, 3.12.2015 Folie 6

Vertical stresses within granular layer

UGM LAYER UGM LAYER

Pavement structure with thick asphalt layer (220mm)

Pavement structure with thin asphalt layer (10mm)

Introduction


Oslo, 3.12.2015 Folie 7

M-E design

Asphalt

Traffic volume Climate Material properties

Layer thicknessModelling

Calculation process

CTB UGL Subgrade

Proof fatigue

ProofPlastic deformation

Proof rutting

fulfilled?

Sufficient designed pavement structure

Modify materials and/or layer thickness

no

yes

RDO Asphalt 09


Oslo, 3.12.2015 Folie 8

Climate Material properties

Model

Calculation process

UGL Subgrade

Accumulated damagesubgrade

Accumulated damagebasecourse

fulfilled?

Sufficient designed pavement structure


no

yes

Traffic volume

Layer thickness

M-E Design

Modified procedure für LVR


Oslo, 3.12.2015 Folie 9

• The deformation performance of UGL is highly importantfor TSAP.

• The current aggregate mix/layer characteristics(DoC/grading lines, particle strenghts) are insufficient forthe evaluation of the deformation performance of UGM.

• Results of lab tests showed that UGM have differentperformance under cyclic loading even if they the havesimilar DoC, MC and grading lines.


Oslo, 3.12.2015 Folie 10

must be determined accorditng to RStO

Min: 250mmMax: 900mm

The minimum thickness for frost protection

Layer thickness: Frost protection

Input Parameter


Oslo, 3.12.2015 Folie 11

Traffic load

0

5

10

15

20

25

30

35

40

45

50

0-2 2-4 4-6 6-8 8-10 10-12 12-14 14-16 16-18 18-20 >20

Achslastklasse [t]

Häu

figke

it [%

]

BAB Fernverkehr

BAB Mischverkehr

BAB Stadtnaher Verkehr

[Data from UHLIG]

LVR < 100,000 10-t-standard axles

In future: Consideration of the actual axle load distribution

Input Parameter


Oslo, 3.12.2015 Folie 12

Conditioning test Resilient test Plastic test

Test package

Test packageApprox 22h

Sample preparation Test set-up

Material characterization


Oslo, 3.12.2015 Folie 13

RL CBR Test


Oslo, 3.12.2015 Folie 14


Property Mixture A Mixture B Mixture C Mixture D Mixture E

Type Natural sandy-gravel

Crushed rock Granodiorite

Crushed rock Andesite

Crushed rockFPM

Crushed rock Granite with

quartz Grain size 0/32 0/32 0/32 0/16 0/32

Maximum dry density

[gr/cm3]2,200 2,170 2,010 2,198 2,000

OMC[m - %] 6,0 5,8 12,1 6,7 5,0

Fine Content 2,5 2,5 2,5 3,3 -


Oslo, 3.12.2015 Folie 15

Ranking procedure for UGM

Conditioning Test:

20.000 LC @Cell pressure of 150kPa Deviatoric stress of 300kPaTests at 70, 80 and 90% of OMC

Characteristic stiffness

Characteristic plastic strain rate



Oslo, 3.12.2015 Folie 16

0

100

200

300

400

500

6000 10 20 30 40 50 60 70 80 90 100 110 120

Char

akte

ristis

cher

Elas

tizitä

tsm

odul

[M

Pa]

Charakteristische plastische Dehnungsrate [‰/106 LW]

AND-0/32

80%

70%

Q1 Q2 Q3

0

100

200

300

400

500

6000 10 20 30 40 50 60 70 80 90 100 110 120

Char

akte

ristis

cher

Elas

tizitä

tsm

odul

[M

Pa]

Charakteristische plastische Dehnungsrate [‰/106 LW]

GRA-0/16

80%

70% 90%

Q1 Q2 Q3

Ranking procedure for UGM

Conditioning Test:

20.000 LC @Cell pressure of 150kPa Deviatoric stress of 300kPa

Q1 Material – excellent materialQ2 Material - good materialQ3 Material - bad material

Q2 MaterialGranit (FP Material)

Q3 MaterialAndesit



Oslo, 3.12.2015 Folie 17

Characterization of elastic deformation behavior


Multistage repeated load triaxial test at CCP


Oslo, 3.12.2015 Folie 18

Results of the RLT tests

-> Determination of the model parameters

0,002,004,006,008,00

10,0012,0014,0016,0018,0020,0022,0024,00

0 50 100 150 200 250 300 350

Vert

ikal

e de

viat

orisc

he p

last

ische

Deh

nung

[‰

]

Lastwechsel [-] Tausende

GRA-0/32-70-1

GRA-0/32-80-2

GRA-0/32-90-1

0

100

200

300

400

500

600

700

0 100 200 300 400 500 600

Elas

tizi

täts

mod

ul [M

Pa]

Deviatorspannung [kPa]

100 130150 180210 250

Zelldruck σ3 [kPa]

Elastic deformation performance Plastic deformation performance



Oslo, 3.12.2015 Folie 19

( ) ( ) ( ) λεε ⋅−+= 01,1,0

NNNplabp

Modeling of permanent deformation response


Oslo, 3.12.2015 Folie 20

Stiffness changes of the BC/subgrade due to changing moisture content during the year

Climate

[ERLINSON 09]


Oslo, 3.12.2015 Folie 21

ZONE 1

ZONE 2

Thaw period45,1%

Thaw period44,0%

Climatic conditionGermany Sweden


Oslo, 3.12.2015 Folie 22

Climate Material properties

Model

Calculation process

UGL Subgrade

Accumulated damagesubgrade

Accumulated damagebasecourse

fulfilled?

End


no

yes

Traffic volume

Layer thickness

M-E Design


Oslo, 3.12.2015 Folie 23

Asphalt

UGL

Subbase

Subgrade

1. Calculation of plastic deformation of the UGL Representative elastic strains in the UGM at three sublayersof a thickness of 100mm

2. Vertical compressive strain/stress at top subbase

3. Vertical compressive strain/stress at top subgrade

100mm

100mm

100mm

M-E Design

Design process


Oslo, 3.12.2015 Folie 24

Plastic deformation UGL

( ) 008,41,57,37

labrελ ⋅=

BasecourseMaterial

Target W.C. k1 k2 k3[% of OWC] [MPa] [-] [-]

GRA 70 358.3 0.5923 -0.1946

Elastic strains Plastic strains

M-E Design

32

11

k

a

oct

k

a PPpkMr

+

=

τ

Elastic strain distribution


Oslo, 3.12.2015 Folie 25

Performance Criteria Subgrade/FPL: plastic deformation

Austroads (Australia)

Sweden design code

German ME design code

Bas

ed o

n S

trai

nB

ased

on

Str

ess

M-E design


Oslo, 3.12.2015 Folie 26

Thaw period

Material parameter: Asphalt – no structural layer

Layer Layer modulus (E-Modulus)

Poisson‘sratio

Materialbehavior

Asphaltt<20mm

E=(5.000 MPa)(Membrane behaviour)

µ = 0,35 Linear elastic

Asphaltt>20mm

E=5.000 MPaStandard condition

E=10.000 MPaThaw period

µ = 0,35 Linear elastic

M-E design


Oslo, 3.12.2015 Folie 27

• Using the results of RLTT on UGM the basis for the ME design of TSAP was established

• It is possible to have pavement structures with asphalt layers of less than 40mm thickness for low trafficked pavements in Germany

• Only high quality UGMs that have high stiffness and low susceptibility to plastic deformation even at high moisture contents should be used in TSAP.

Conclusiones


Oslo, 3.12.2015 Folie 28

Acknowledgement

This presentation is based on parts of the researchproject carried out at the request of the FederalMinistry of Transport, Building and UrbanDevelopment, represented by the Federal HighwayResearch Institute under research project No.09.0175/2011/ERB.

THE GERMAN EMPIRICAL–MECHANISTIC DESIGN SYSTEM PART … · 2016-02-09 · Fakultät...

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