Reinforcement Corrosion: Numerical Simulation and Service ......Reinforcement Corrosion: Numerical Simulation and Service Life Prediction Alexander Michel & Henrik Stang Sponsored

Reinforcement Corrosion: Numerical Simulation and Service Life PredictionAlexander Michel & Henrik Stang

Sponsored by • Femern Bælt A/S• Sund & Bælt Holding A/S• The Danish Agency for Science, Technology and

Innovation

Dansk Ekspertcenter for konstruktioner til infrastrukturen– resultater og perspektiver

March 14th 2013Copenhagen, Denmark

DTU Civil Engineering, Technical University of Denmark

BACKGROUND AND MOTIVATION

• Deterioration of the civil infrastructure presents major challenges to society

• Costs for maintenance, renovation, and renewing are growing and taking up a major part of concrete structure investments

– US > $ 20 billion (infrastructure, 2002)– UK > £ 550 million (annual costs, 2005)– Toronto > $ 110 million (roads, sidewalks and bridges, 2005)

2 15 March 2013

http://corrosion.ksc.nasa.gov

http://www.matcoinc.com

http://www.zoranthepainter.com.au


STATE-OF-THE-ART (1 OF 2)• Service life modelling

– ingress of corrosion-initiating substances– propagation phase is (often) neglected

3 15 March 2013

[Tuutti 1982]

Con

dit

ion

of

Str

uct

ure

Initiation phase Propagation phase

Typical service life model

End of service

life

Age of Structure


STATE-OF-THE-ART (2 OF 2)• Service life modelling

– ingress of corrosion-initiating substances– propagation phase of reinforcement corrosion

4 15 March, 2013

[Pease et al. 2012]

Con

dit

ion

of

Str

uct

ure

Initiation phase Propagation phase

Typical service life model

End of service

life

Age of Structure

Modified service life model

Initiationphase

Propagation phase


SCOPE (1 OF 2)• Conceptual model for service life modelling

– ingress of corrosion-initiating substances– propagation phase of reinforcement corrosion– corrosion-induced damage

5 15 March, 2013

CathodeCathode

Reinforcement

Concrete

Moisture, temperature, oxygen, chloride, carbon dioxide

Anode


Microstructure

Temperature

Moisture Ions

Oxygen

Resistivity

Temperature

Moisture

Ions

Oxygen

Cracking

Debonding

Properties

Material and transport

model

Servicelife

prediction

SCOPE (2 OF 2)

6 15 March 2013

[Michel et al. 2010]


OUTLINE OF PRESENTATION

• Transport of heat and mass in concrete– Coupled heat and moisture transport– Multi-ion transport

• Corrosion of steel in concrete– Modelling of reinforcement corrosion– Influence of temperature, oxygen, and moisture

• Initiation and propagation of reinforcement corrosion

• Corrosion-induced concrete damage– Modelling approach– Penetration of corrosion products

• Summary and conclusions

• Future developments

7 15 March 2013









8 15 March, 2013


TRANSPORT OF HEAT AND MASS IN CONCRETE

• Mass balance equations

• Comparison experimental and numerical results

9 15 March, 2013

Microstructure

Temperature

Moisture Ions

Oxygen


model

Servicelife

prediction

, , T T T pCTC k T k pCt

, , l cpC pC pC pC T

c

p pCC k pC k Tp pC t

Reinforcement

Concrete

Moisture and temperature


TRANSPORT OF HEAT AND MASS IN CONCRETE

• Nernst-Planck equation


10 15 March, 2013

Microstructure

Temperature

Moisture Ions

Oxygen


model

Servicelife

prediction

,i

i i i m i i ic D c z u Fc V c vt

2 2 24, , , , ,i Cl OH SO Ca Na K Mg

Reinforcement

Concrete

Ions (e.g.: chloride)









11 15 March, 2013


CORROSION OF STEEL IN CONCRETE

• Modelling reinforcement corrosion

– corrosion current and potential

– polarisation

12 15 March, 2013

Resistivity

Temperature

Moisture

Ions

Oxygen

Servicelife

prediction 1corr

conc

Ein

2 0E

0, A A Ai i exp

C0,

0, lim C

11 i / iC C

Ci i exp

0, /A/C 10 A CE E

lnb

10 RTb lnzF

22

Olim O

zFDi cCathodeCathode

Concrete

Moisture, temperature, oxygen, chloride

Anode

Reinforcement



• Influence of temperature


13 15 March, 2013

Resistivity

Temperature

Moisture

Ions

Oxygen

Servicelife

prediction0

0, 0,1 1

T RefRef

zFEi i expR T T

CathodeCathode

Concrete

Temperature

Anode

Reinforcement



• Influence oxygen

14 15 March, 2013

Resistivity

Temperature

Moisture

Ions

Oxygen

Servicelife

prediction

[Raupach 1996]

CathodeCathode

Concrete

Oxygen

Anode

Reinforcement



• Influence of moisture

15 15 March, 2013

Resistivity

Temperature

Moisture

Ions

Oxygen

Servicelife

prediction(all dimensionsin mm)

Anodes

Cathode

CathodeCathode

Concrete

Moisture

Anode

Reinforcement









16 15 March, 2013


INITIATION AND PROPAGATION OF CORROSION

• Definition of a conditional statement (critical chloride threshold) for elements along the reinforcement surface

17 15 March, 2013

a cl critSteel

c cl crit

i c cBC for

i c c


model

Servicelife

prediction

CathodeCathode

Concrete


Anode

Reinforcement

0

-90

90

180

0.05%

0.20%

Concrete

Rebar

Rebar

Chloride



18 15 March, 2013

(all dimensions in m)CathodeCathode

Concrete


Anode

Reinforcement



19 15 March, 2013


IMPACT OF CRACKS

20 15 March, 2013

(all dimensions in m)


model

Servicelife

prediction


IMPACT OF CRACKS

21 15 March, 2013









22 15 March, 2013


CORROSION-INDUCED CONCRETE DAMAGE

• Modelling approach– uniform corrosion along the

reinforcement– 2D plain strain formulation

23 15 March, 2013

CathodeCathode

Reinforcement

Concrete

Moisture, etc.

Anode

Non corrodedreinforcementsection

Corrodedreinforcementsection

Expandedcorrosionlayer

R0

R1

R2

R0=R2 R0

T

R0=(R0 R1)• • T

0

tFe

corrFe

MX t i t dtzF


model

Servicelife

prediction



• Penetration of corrosion products

24 15 March, 2013

[Pease et al. 2012]



• Non-uniform corrosion

25 15 March, 2013

[Thybo et al. 2013]









26 15 March, 2013

DTU Civil Engineering, Technical University of Denmark27

SUMMARY AND CONCLUSIONS

• Coupled transport and corrosion processes– allow for the simulation of initiation and propagation of chloride-

induced corrosion in reinforced concrete– may be used to predict the service life of reinforced concrete if a

certain limit state, e.g. initiation of corrosion or certain cross sectional reduction, is set

– governing parameters can be assessed with the model and used to optimise structures in terms of service life

15 March, 2013


model

Service life

prediction CathodeCathode

Concrete


Anode

Reinforcement



• Corrosion-induced concrete damage– thermal analogy may be used to mimic any type of solid corrosion

product that is formed– penetration of corrosion products into cementitious materials has a

considerable influence on the time-to crack initiation and propagation– model can be used to investigate the impact of varying geometrical

parameters and material properties on the formation and propagation of cracks

15 March, 2013


model

Service life

prediction CathodeCathode

Reinforcement

Concrete

Moisture, etc.

Anode



• Impact of cracks– allow to account for the impact of cracks on the ingress of potential

corrosion-initiating substances – provide more realistic predictions on the initiation and propagation of

reinforcement corrosion

15 March, 2013

CathodeCathode

Reinforcement

Concrete

Moisture, etc.

Anode


model

Service life

prediction









30 15 March, 2013


ShapeMaterial

Properties

StructuralProperties

Loads

Maintenance

InfrastructurePerformance

Materials

Structure

System

EnvironmentalIndicators

InfrastructureSustainability

SocialIndicators

EconomicIndicatorsEvaluation

MaterialProduction

Constituents

MaterialMicrostructure

Construction

Design for Sustainability

Life CycleAssessment

FUTURE DEVELOPMENTS (1 OF 2)• Establish a cross disciplinary research approach including

– industrial ecology methods, quantitative sustainability assessment practices, environmental impact measurement,ecosystem service valuation, social impact measurement, life cycle costing,

– theoretical infrastructure deterioration modelling, advanced materials design,

– emerging transportation infrastructure,innovations, risk and reliability of transportation infrastructure,

– and probabilistic design methods

31 15 March, 2013

[Lepech et al. 2011]


FUTURE DEVELOPMENTS (2 OF 2)

32 15 March, 2013

Structural Performance

Module (3D +Time)Structural Capacity

Sustainability Indicators

Material PerformanceModule (3D + Time)

Corrosion RatesCorrosion Potentials

Types of Corrosion Products

Mechanical Performance

Module (2D + Time)Corrosion-induced DamageChemical-induced Damage

Transport and Chemical Module (1D + Time)

States of Heat and MatterChemical Compositions

Changes in Microstructure

InterfaceModule

[Michel et al. 2013]


COMMITMENT

33 15 March, 2013

• Expert-center commitment to establish poof of concept model and to work on experimental verification

• Further commitment (involving existing projects and seeking funding for new) from:

– Stanford University (sustainability, exposure simulation and structural performance)

– DTU (transport, corrosion and construction of the unified model)– NTNU (transport corrosion and structural performance)

• Foreseen commitment from:– Danish road Directorate (real bridge) – …


Thank you for your attention

34

[Küter 2009]

Documents

Reinforcement Corrosion: Numerical Simulation and Service ......Reinforcement Corrosion: Numerical Simulation and Service Life Prediction Alexander Michel & Henrik Stang Sponsored