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Fatigue of Asphalt Mixes - Theory of Viscoelasticity and Continuum Damage Mechanics Applied to Uniaxial Fatigue Data from Laboratory Tests

Nilsson, Richard LU (2003) In Bulletin vägbyggnad 15.
Abstract (Swedish)
Popular Abstract in Swedish

I takt med att analytiska dimensioneringsmetoder utvecklas ökar även behovet av att kunna bestämma mekaniska egenskaper hos materialen i överbyggnaden och terrassen. Utmattningssprickor orsakade av tung trafik, permanenta deformationer (spårbildning), termisk sprickbildning, ojämnheter, tjäle och reflektionssprickor är några av de dimensioneringskriterier som kan användas då en väg dimensioneras.



Syftet med doktorsavhandlingen är att utvärdera existerande modeller, som används för att beskriva utmattning av asfaltbeläggningar. Exempelvis ATB VÄG, Asphalt Institutes kriterium, Shells kriterium etc. och eventuellt också hitta en förbättrad modell som skulle kunna användas i en... (More)
Popular Abstract in Swedish

I takt med att analytiska dimensioneringsmetoder utvecklas ökar även behovet av att kunna bestämma mekaniska egenskaper hos materialen i överbyggnaden och terrassen. Utmattningssprickor orsakade av tung trafik, permanenta deformationer (spårbildning), termisk sprickbildning, ojämnheter, tjäle och reflektionssprickor är några av de dimensioneringskriterier som kan användas då en väg dimensioneras.



Syftet med doktorsavhandlingen är att utvärdera existerande modeller, som används för att beskriva utmattning av asfaltbeläggningar. Exempelvis ATB VÄG, Asphalt Institutes kriterium, Shells kriterium etc. och eventuellt också hitta en förbättrad modell som skulle kunna användas i en strukturell responsmodell i framtiden. Olika Continuum Damage Mechanics (CDM) modeller kommer också att utvärderas. Erhållna resultat med dessa modeller kommer att jämföras med resultat erhållna med mera traditionella metoder. I projektet har också enaxiella laboratorieförsök utvärderats.



I projektet har tre typer av massor använts, en standard bärlagermassa AG16, 4.8 %, 160/220 tillsammans med två alternativa massor kallade Inorbind16, 5.3 %, 70/100 + fiber och Durabind16, 4.3 %, 70/100 + polymer.



Frekvenssvep, hållfasthetsförsök med konstant belastningshastighet (monotoniska försök) och utmattningsförsök (cykliska försök) utfördes på provkroppar från laboratorietillverkade plattor. Från varje platta borrades 10 provkroppar (Ø 75 mm) ut med en portabel borrutrustning. Efter borrningen kapades provkopparna till en höjd av 150 mm (2:1 förhållande). Försöken utfördes med en servohydraulisk utrustning, UTM-25 (Universal Testing Machine-25 kN) levererad av Industrial Process Controls Ltd (IPC), Australien.



Den modell som har den största potentialen i framtiden är modellen som utvecklats av Schapery och baseras på viskoelasticitet och continuum damage mechanics. Genom att använda pseudotöjningskonceptet var det möjligt att separera de viskoelastiska effekterna från skadeackumuleringen i provkroppen och materialets hastighetsberoende egenskaper kunde elimineras. Genom att använda tid-temperatursuperpositioneringsprincipen och samma skiftfaktorer som användes för att skapa masterkurvorna var det möjligt att skifta de karakteristiska materialfunktionerna mellan olika temperaturer. Det var även möjligt att beskriva olika typer av försök, monotoniska samt spänningsstyrda och töjningsstyrda cykliska försök, med en karakteristisk materialfunktion. Försöken utfördes med olika belastningshastighet för de monotoniska försöken och med olika spännings- och töjningsnivåer samt frekvenser för de cykliska försöken. Dessa observationer gör det möjligt att minska antalet testade provkroppar eftersom cykliskt beteende kan predikters från enkla och snabba monotoniska tester vilket är en stor förbättring jämfört med konventionella metoder. (Less)
Abstract
The advance of analytic (mechanistic) design methods increases the need for fundamental material properties. Fatigue cracking due to traffic loading, in combination with permanent deformation (rutting), thermal cracking, irregularities, frost heave and reflective cracking are some of the major criteria used when designing an asphalt concrete pavement.



The objective of this Ph.D. project is to evaluate existing material models used to evaluate the fatigue-life of an asphalt concrete pavement, e.g. ATB VÄG, the Shell Criterion, the Asphalt Institute Criterion etc. and, eventually, to find an improved material model that can be used in a structural response model. Different Continuum Damage Mechanics (CDM) models are also... (More)
The advance of analytic (mechanistic) design methods increases the need for fundamental material properties. Fatigue cracking due to traffic loading, in combination with permanent deformation (rutting), thermal cracking, irregularities, frost heave and reflective cracking are some of the major criteria used when designing an asphalt concrete pavement.



The objective of this Ph.D. project is to evaluate existing material models used to evaluate the fatigue-life of an asphalt concrete pavement, e.g. ATB VÄG, the Shell Criterion, the Asphalt Institute Criterion etc. and, eventually, to find an improved material model that can be used in a structural response model. Different Continuum Damage Mechanics (CDM) models are also evaluated, and the results are compared with results obtained with traditional methods for fatigue-life evaluation, i.e. linear logarithmic relations between initial strain and number of cycles to failure. Uniaxial laboratory fatigue testing will also be evaluated in this project.



Three types of asphalt mixes were used in this research: a standard Swedish base-course mixture called AG16, 4.8 %, 160/220 together with two alternative mixes called Inorbind16, 5.3 %, 70/100 + fiber and Durabind16, 4.3 %, 70/100 + polymer.



Frequency sweep tests, constant strain rate monotonic tests and cyclic fatigue test were performed on specimens cored from laboratory-manufactured plates. Ten Ø 75-mm specimens were cored from each plate using portable coring equipment. After coring, specimens were cut, resulting in specimens with a height equal to 150 mm (2:1 ratio). The tests were performed using a dynamic servo hydraulic test machine, UTM-25 (Universal Testing Machine-25 kN) supplied by Industrial Process Controls Ltd (IPC), Australia.



The model that has the largest potential for the future is the one based on uniaxial constitutive modeling using viscoelasticity and continuum damage mechanics based on Schapery’s theories. By using the pseudostrain concept and separating the viscoelastic effects from damage accumulation in the specimen, it was possible to eliminate the rate dependency for the material. By using the time-temperature superposition principle and the same shift factors that were used when the mastercurve was developed, it was possible to shift the characteristic material functions between different temperatures. It was also possible to describe monotonic and cyclic tests of both the controlled-strain and controlled-stress type, using one single characteristic material function. The tests were performed using different loading rates for monotonic tests and different stress and strain levels as well as frequencies for the cyclic tests. This observation makes it possible to reduce the number of specimens tested and time-consuming fatigue tests are no longer necessary, since the same information can be obtained from monotonic test data. (Less)
Please use this url to cite or link to this publication:
author
opponent
  • Prof Harvey, John T, University of California, Davis
organization
publishing date
type
Thesis
publication status
published
subject
keywords
asphalt mixture, viscoelastic, Fatigue, deterioration models, Continuum Damage Mechanics, laboratory test, uniaxial, hydraulic engineering, Civil engineering, offshore technology, soil mechanics, Väg- och vattenbyggnadsteknik
in
Bulletin vägbyggnad
volume
15
pages
272 pages
publisher
Department of Technology and Society, Lund University
defense location
V-house, Room V:C
defense date
2003-02-11 10:15
external identifiers
  • other:ISRN: LUTVDG/(TTVB-1003)1-272/2003
ISSN
1404-4331
language
English
LU publication?
yes
id
1da47d95-d935-4d71-8b04-0b504e7770ca (old id 21001)
date added to LUP
2007-05-28 14:09:58
date last changed
2016-09-19 08:44:56
@phdthesis{1da47d95-d935-4d71-8b04-0b504e7770ca,
  abstract     = {The advance of analytic (mechanistic) design methods increases the need for fundamental material properties. Fatigue cracking due to traffic loading, in combination with permanent deformation (rutting), thermal cracking, irregularities, frost heave and reflective cracking are some of the major criteria used when designing an asphalt concrete pavement.<br/><br>
<br/><br>
The objective of this Ph.D. project is to evaluate existing material models used to evaluate the fatigue-life of an asphalt concrete pavement, e.g. ATB VÄG, the Shell Criterion, the Asphalt Institute Criterion etc. and, eventually, to find an improved material model that can be used in a structural response model. Different Continuum Damage Mechanics (CDM) models are also evaluated, and the results are compared with results obtained with traditional methods for fatigue-life evaluation, i.e. linear logarithmic relations between initial strain and number of cycles to failure. Uniaxial laboratory fatigue testing will also be evaluated in this project.<br/><br>
<br/><br>
Three types of asphalt mixes were used in this research: a standard Swedish base-course mixture called AG16, 4.8 %, 160/220 together with two alternative mixes called Inorbind16, 5.3 %, 70/100 + fiber and Durabind16, 4.3 %, 70/100 + polymer.<br/><br>
<br/><br>
Frequency sweep tests, constant strain rate monotonic tests and cyclic fatigue test were performed on specimens cored from laboratory-manufactured plates. Ten Ø 75-mm specimens were cored from each plate using portable coring equipment. After coring, specimens were cut, resulting in specimens with a height equal to 150 mm (2:1 ratio). The tests were performed using a dynamic servo hydraulic test machine, UTM-25 (Universal Testing Machine-25 kN) supplied by Industrial Process Controls Ltd (IPC), Australia.<br/><br>
<br/><br>
The model that has the largest potential for the future is the one based on uniaxial constitutive modeling using viscoelasticity and continuum damage mechanics based on Schapery’s theories. By using the pseudostrain concept and separating the viscoelastic effects from damage accumulation in the specimen, it was possible to eliminate the rate dependency for the material. By using the time-temperature superposition principle and the same shift factors that were used when the mastercurve was developed, it was possible to shift the characteristic material functions between different temperatures. It was also possible to describe monotonic and cyclic tests of both the controlled-strain and controlled-stress type, using one single characteristic material function. The tests were performed using different loading rates for monotonic tests and different stress and strain levels as well as frequencies for the cyclic tests. This observation makes it possible to reduce the number of specimens tested and time-consuming fatigue tests are no longer necessary, since the same information can be obtained from monotonic test data.},
  author       = {Nilsson, Richard},
  issn         = {1404-4331},
  keyword      = {asphalt mixture,viscoelastic,Fatigue,deterioration models,Continuum Damage Mechanics,laboratory test,uniaxial,hydraulic engineering,Civil engineering,offshore technology,soil mechanics,Väg- och vattenbyggnadsteknik},
  language     = {eng},
  pages        = {272},
  publisher    = {Department of Technology and Society, Lund University},
  school       = {Lund University},
  series       = {Bulletin vägbyggnad},
  title        = {Fatigue of Asphalt Mixes - Theory of Viscoelasticity and Continuum Damage Mechanics Applied to Uniaxial Fatigue Data from Laboratory Tests},
  volume       = {15},
  year         = {2003},
}