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Institute for Mechanics of Materials and Structures TU Wien – Vienna University of Technology, Austria
GillesChanvillardMemorialSymposium,ENPC,July5,2016
1/25
Institute for Mechanics of Materials and Structures TU Wien – Vienna University of Technology, Austria
GillesChanvillardMemorialSymposium,ENPC,July5,2016
2/25
Frommicrostructuretomacroproper.es:strengthandcreepofcemen..ousmaterials
M.Hlobil,M.Irfan-ul-Hassan,M.Königsberger,R.Reihsner,Ch.Hellmich,B.Pichler
TUWien-ViennaUniversityofTechnology,AustriaInsRtuteforMechanicsofMaterialsandStructures
Bernhard.Pichler@tuwien.ac.at
Institute for Mechanics of Materials and Structures TU Wien – Vienna University of Technology, Austria
GillesChanvillardMemorialSymposium,ENPC,July5,2016
3/25
Mo.va.on:Ø cemenRRousmaterialsarehierarchicallyorganizedØ (sub)micron-sizedhydrateneedlesgoverncreepandstrengthof
cemenRRousmaterials
ChaYerjiandJeffrey,Nature,209,1966 hYp://www.^wa.dot.govhYp://www.^wa.dot.gov
TriYhart&Häußler,CCR,2003
Institute for Mechanics of Materials and Structures TU Wien – Vienna University of Technology, Austria
GillesChanvillardMemorialSymposium,ENPC,July5,2016
4/25
Outline
Creep1. Hourly-repeated,3mincreeptesRngatearlyages2. IdenRficaRonofhydratecreepfuncRon+validaRon
Strength
1. ElasRclimitmodelforcementpastes
Institute for Mechanics of Materials and Structures TU Wien – Vienna University of Technology, Austria
GillesChanvillardMemorialSymposium,ENPC,July5,2016
5/25
Early-agetes.ngdilemma:couplingbetweencreepandhydra.onØ duraRonofcreeptests>>characterisRcRmeofhydraRonØ Microstructuraldevelopment(“aging”)duringcreeptest
Aim:decouplecreepandhydra.onØ Characterizecreepofspecific(“non-aging”)microstructures
Solu.on:newtestprotocolØ 3minutecreeptests
…referringtospecificmicrostructuresØ hourlyrepeated
…successivecreeptestsrefertodifferentmicrostructures
Lit.:[Irfan-ul-Hassanetal.,Cement&ConcreteResearch,82:36-49,2016]
Institute for Mechanics of Materials and Structures TU Wien – Vienna University of Technology, Austria
GillesChanvillardMemorialSymposium,ENPC,July5,2016
6/25
Materials:OPCcementpastes Testsetup:Rawmaterials• CEMI42.5N• disRlledwater
ComposiRons• w/c=0.42/0.45/0.50
Cylindricalspecimens• diameter=7cm• height=30cm
CuringcondiRons• ambientairtemp=20oC• sealed(nodrying)
aluminumrings
holdingLVDTs
boYleneckedsteelcylinder
5LVDTsequallyspacedaroundspecimen
compressiveloading
specimen
Lit.:[Irfan-ul-Hassanetal.,Cement&ConcreteResearch,82:36-49,2016]
Institute for Mechanics of Materials and Structures TU Wien – Vienna University of Technology, Austria
GillesChanvillardMemorialSymposium,ENPC,July5,2016
7/25
Loadinghistory:• loading:….2MPa/s• unloading:1MPa/s
permanentloadlevel=0.2kN
force
Rme3min
[PichlerHellmich,CemConRes,41,2011]
sampleage[h]appliedforce[kN]
w/c=0.50
Hourlyrepeated:• From21hoursaterproducRonupto8days
170creeptestsperspecimen:forcelevel=max.15%ofstrengthatRmeoftesRng,determinedby• calorimetry• validatedstrengthmodel
Lit.:[Irfan-ul-Hassanetal.,Cement&ConcreteResearch,82:36-49,2016]
Institute for Mechanics of Materials and Structures TU Wien – Vienna University of Technology, Austria
GillesChanvillardMemorialSymposium,ENPC,July5,2016
8/25
LVDTreadings:• smalldifferenceof
5individualLVDTreadingsØ verysmalleccentricityØ meanvaluemeaningful
unloading
mod
ulus[G
Pa]
Rme[sec]3min
LVDT
shortening[μ
m]
ageofmaterial[h]
Quan.fica.onofunloadingmodulus:
meanoutof5readings
w/c=0.50
stress[M
Pa]
strain[10-6]
r2=99.7%
Datafrom1test Datafrom170tests
Lit.:[Irfan-ul-Hassanetal.,Cement&ConcreteResearch,82:36-49,2016]
Institute for Mechanics of Materials and Structures TU Wien – Vienna University of Technology, Austria
GillesChanvillardMemorialSymposium,ENPC,July5,2016
9/25
Quan.fica.onofelas+cmodulus:Ø QuanRfycreepstrains
Ø IdenRfyelasRcmodulusbyavoidingtensilecreepstrains El
asRcm
odulus[G
Pa]
ageofmaterial[h]
w/c=0.50
datafrom340tests
Lit.:[Irfan-ul-Hassanetal.,Cement&ConcreteResearch,82:36-49,2016]
creepstrain[1
0-6 ]
“creep
strain”[10-
6 ]
“creep
strain”[10-
6 ]
Rme[s]Rme[s]Rme[s]
Institute for Mechanics of Materials and Structures TU Wien – Vienna University of Technology, Austria
GillesChanvillardMemorialSymposium,ENPC,July5,2016
10/25
Creepstrainevolu.on:Ø fiyngbasedonpowerlaw
power-la
w
expo
nent[-]
Rme[sec]3min
creepstrain[1
0-6 ]
ageofmaterial[h]
Evolu.onsofcreepmodulusandofpower-lawexponent:
measurements
w/c=0.50
modeled
w/c=0.50
ageofmaterial[h]
creepmod
ulus
[GP
a]
datafrom2samples
datafrom2samples
Lit.:[Irfan-ul-Hassanetal.,Cement&ConcreteResearch,82:36-49,2016]
Institute for Mechanics of Materials and Structures TU Wien – Vienna University of Technology, Austria
GillesChanvillardMemorialSymposium,ENPC,July5,2016
11/25
Hydra.ondegreeratherthanmaterialageØ calorimetryat20oC
ageofmaterial[h]hydraR
ondegree[-]
hydraRondegree[-]
Evolu.onofelas.cmodulus:Ø ElasRcmodulus
increaseslinearlywithhydraRondegree
measurements
w/c=0.50
modeled
datafrom2samples
w/c=0.50
20oC
elasRcm
odulus
[GP
a]
Lit.:[Irfan-ul-Hassanetal.,Cement&ConcreteResearch,82:36-49,2016]
Institute for Mechanics of Materials and Structures TU Wien – Vienna University of Technology, Austria
GillesChanvillardMemorialSymposium,ENPC,July5,2016
12/25
power-la
w
expo
nent[-]
Evolu.onsofcreepmodulusandofpower-lawexponent:
w/c=0.50
hydraRondegree[-]
creepmod
ulus
[GP
a]
datafrom2tests
datafrom2samples
hydraRondegree[-]
datafrom2samples
w/c=0.50 w/c=0.50
Ø Creepmodulus
increasesoverlinearlywithhydraRondegree
Ø Power-lawexponent
decreaseslinearlywithhydraRondegree
Lit.:[Irfan-ul-Hassanetal.,Cement&ConcreteResearch,82:36-49,2016]
Institute for Mechanics of Materials and Structures TU Wien – Vienna University of Technology, Austria
GillesChanvillardMemorialSymposium,ENPC,July5,2016
13/25
Summaryoftes.ngac.vi.es:Ø 500non-agingcreepfuncRonsofcementpasteswith
w/c={0.42,0.45,0.50}
hydraRondegree[-] hydraRondegree[-] hydraRondegree[-]ElasRcm
odulus[G
Pa]
Creepmod
ulus[G
Pa]
Creepexpo
nent[-]
Lit.:[Irfan-ul-Hassanetal.,Cement&ConcreteResearch,82:36-49,2016]
Institute for Mechanics of Materials and Structures TU Wien – Vienna University of Technology, Austria
GillesChanvillardMemorialSymposium,ENPC,July5,2016
14/25
Karteetal.(2014)ultrasound
Quasi-sta.cYoung’smodulivs.dynamicYoung’smoduli
hydraRondegree[-]
w/c=0.42w/c=0.50
Youn
g’sm
odulus[G
Pa]
hydraRondegree[-]Yo
ung’sm
odulus[G
Pa]
w/c=0.42
w/c=0.50
presentstudyquasistaRc
Conclusion:Quasi-staRcYoung’smoduli=dynamicYoung’smoduli
Lit.:[Irfan-ul-Hassanetal.,Cement&ConcreteResearch,82:36-49,2016]
Institute for Mechanics of Materials and Structures TU Wien – Vienna University of Technology, Austria
GillesChanvillardMemorialSymposium,ENPC,July5,2016
15/25
Outline
Creep1. Hourly-repeated,3mincreeptesRngatearlyages2. IdenRficaRonofhydratecreepfuncRon+validaRon
Strength
1. ElasRclimitmodelforcementpastes
Institute for Mechanics of Materials and Structures TU Wien – Vienna University of Technology, Austria
GillesChanvillardMemorialSymposium,ENPC,July5,2016
16/25
Mul.scaleexploita.onofcreeptestdata1. IdenRfycreepofmicron-sizedhydrateneedles
Creephomogeniza.on:Correspondenceprinciplea. Laplace-CarsontransformaRonofRme-dependentproblem
b. Quasi-elasRcupscalingusingconRnuummicromechanics,i.e.Eshelby-basedhomogenizaRonschemes
c. Back-transformaRontoRmespace
hYp://www.^wa.dot.gov
cementpaste
ChaYerji&Jeffrey,Nature,209,1966
hydratefoam
1
hydrateneedle
Literature:[Königsbergeretal.,JournalofEngineeringMechanics,accepted]
Institute for Mechanics of Materials and Structures TU Wien – Vienna University of Technology, Austria
GillesChanvillardMemorialSymposium,ENPC,July5,2016
17/25
1.Iden.fica.onofcreepofhydrateneedlesØ PhasevolumefracRons:Powers-AckerhydraRonmodel
Powers,Brownyard,Res.Lab.Port.Cem.Ass.Bull,22101-992,1948
Ackeretal.inConcreteatEarlyAges,ACI,33-48,1986
Literature:[Königsbergeretal.,JournalofEngineeringMechanics,accepted]
Institute for Mechanics of Materials and Structures TU Wien – Vienna University of Technology, Austria
GillesChanvillardMemorialSymposium,ENPC,July5,2016
18/25
1. Iden.fica.onofcreepofhydrateneedles
Ø Ansatz:isochoriccreepofneedle-shapedhydrates
Ø ElasRcproperRes:Ø CreepproperRes:??
cementpaste hydratefoam
Literature:[Königsbergeretal.,JournalofEngineeringMechanics,accepted]
hydrateneedle
Institute for Mechanics of Materials and Structures TU Wien – Vienna University of Technology, Austria
GillesChanvillardMemorialSymposium,ENPC,July5,2016
19/25
Experimentaldatavs.homogeniza.onresults:creepofcementpaste
Iden.fiedconstants:
Literature:[Königsbergeretal.,JournalofEngineeringMechanics,accepted]
Institute for Mechanics of Materials and Structures TU Wien – Vienna University of Technology, Austria
GillesChanvillardMemorialSymposium,ENPC,July5,2016
20/25
IshydratecreepwithconstantPoisson’sra.omorerealis.c?Ø AlternaRveansatzforhydratecreepfuncRon
Ø IdenRficaRonresults:isochoriccreepvs.constantPoisson’sraRo
Ø IsochoriccreepandcreepwithconstantPoisson’sraRodeliverthesamecreepmodulusandthesamecreepexponent
Literature:[Königsbergeretal.,JournalofEngineeringMechanics,accepted]
hydrateneedle
Institute for Mechanics of Materials and Structures TU Wien – Vienna University of Technology, Austria
GillesChanvillardMemorialSymposium,ENPC,July5,2016
21/25
Modelvalida.onbasedontestsbyTamtsiaandBeaudoin(2000)Ø ComposiRonofcementpaste:w/c=0.50Ø Curing:30yearsunderwater->hydraRondegree=87%Ø CreeptestduraRon:30days
CreepfuncRo
n
[10-
6 /MPa]
CreeptestduraRon[days]
experiments
modelpredic.ons
Literature:[Königsbergeretal.,JournalofEngineeringMechanics,accepted]
Institute for Mechanics of Materials and Structures TU Wien – Vienna University of Technology, Austria
GillesChanvillardMemorialSymposium,ENPC,July5,2016
22/25
Outline
Creep1. Hourly-repeated,3mincreeptesRngatearlyages2. IdenRficaRonofhydratecreepfuncRon+validaRon
Strength
1. ElasRclimitmodelforcementpastes
Institute for Mechanics of Materials and Structures TU Wien – Vienna University of Technology, Austria
GillesChanvillardMemorialSymposium,ENPC,July5,2016
23/25
Mul.scalemodeling:con.nuummicromechanics
ChaYerjiandJeffrey,Nature,209,1966 hYp://www.^wa.dot.govhYp://www.^wa.dot.gov
Materialphasesinscale-separatedhierarchicalorganiza.on
Strengthmodelingidea:• CemenRRousmaterialsareintact,ifdeviatoric
stresspeaksinhydrates<hydratestrength
RVE of shotcrete RVE of cement paste RVE of hydrate foam RVE of concrete
Lit.:[Pichler&Hellmich,CementandConcreteResearch,2011]
Institute for Mechanics of Materials and Structures TU Wien – Vienna University of Technology, Austria
GillesChanvillardMemorialSymposium,ENPC,July5,2016
24/25
Mul.scalemodelingofstrengthofcementpaste
• Cementpasteisintact,ifdeviatoricstresspeaksinhydrates<hydratestrength
• Microscopichydratefailure=macroscopicmaterialstrength
Scaletransi.ontostresspeaks:via2ndorderstressaverages
Iden.fica.onofhydratestrengthØ NanoindentaRontesRngonlow-densityC-S-H:
• cohesionc=50MPa• angleofinternalfricRonφ=12o
Ø Thisimplies:• Uniaxialcompressivestrengthofhydratesfcu,hyd=123.5MPa• vonMises-typedeviatoricstrength=71.3MPa
ConstanRnidesandUlm,MITReport(2006)SarrisandConstanRnides,CCC(2013)
Pichleretal.Concreep,(2013)
macroscopicstress
Lit.:[Pichler&Hellmich,CementandConcreteResearch,2011]
Institute for Mechanics of Materials and Structures TU Wien – Vienna University of Technology, Austria
GillesChanvillardMemorialSymposium,ENPC,July5,2016
25/25
Modelvalida.on Pichleretal.,Concreep,(2013)
Modelvs.testsperformedinVienna
...atLCR
...atEMPA
Pichleretal.,CCR(2013)
Pichleretal.,CCR(2013)
Samemodelperformanceforhydratefailure
accordingtoMohr-Coulombcriterion
Wyrzykowskietal.COSTacRonTU1404
hydraRondegree[-]
Compr.stren
gth[M
Pa]
hydraRondegree[-]Compr.stren
gth[M
Pa]
Compr.stren
gth[M
Pa]
Literature:[Hlobiletal.,ManuscriptinpreparaRon,2016]
hydraRondegree[-]