Corrosion of reinforced concrete structures from the diagnosis to the electrochemical repair [email protected]http://www.ifsttar.fr/accueil/ Chalmers University of Technology Seminar: Fibre reinforced concrete and durability September 13, 2017 French institute of science and technology for transport, development and networks
28
Embed
Seminar: Fibre reinforced concrete and durability ... · Bouteiller et al, Corrosion Reviews 2012 Bouteiller et al, Construction and Building Materials 2016 ... Réaction cathodique
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Two main causes of the corrosion of reinforcement– Complete carbonation of the concrete cover � pH decreases from 13 to 9– Chloride contamination � breakdown of the passive film
Damages– Steel section loss– Cracks...delaminations– Loss of steel/concrete adhesion
4Chalmers seminar - 13 September 2017 - V. Bouteiller
Road bridges– 6 000 national roads (/ 16 000)– 75% surface reinforced or pre-stressed concrete – 35 years old– 10% structurally deficient
Infrastructure plan- Reliable tools for corrosion diagnosis- Simulations to predict the bridge life- New repair solutions based on electrochemical treat ments
Chalmers seminar - 13 September 2017 - V. Bouteiller 5
Detection of the initiation of corrosion / cement a bility to delay the ingress of chloride ionsReinforced micro-concretePortland vs Ground Granulated Blast furnace Slag cem ents NDT electrochemistry and DA chloride profilesCorrelation chloride threshold and performed testsBouteiller et al, Cement and Concrete Research, 2012
Propagation, Cracks
Electrochemical repair treatments
Chalmers seminar - 13 September 2017 - V. Bouteiller 8 / 38
Objectives– Evaluate the cement ability to delay the chloride i ngress and therefore the corrosion – NDT electrochemical measurements (HCP, LPR) and Ico rr
Specimen designParameters
– Cement type Portland or Ground Granulated Blast furnace Slag– Water/cement ratio
Tests– NDT: 10 samples (average) and ↓ number– DA: chloride profiles 1 sample– Autopsies
9 / 38Chalmers seminar - 13 September 2017 - V. Bouteiller
Total chlorides (% weight cement) Free chlorides (% weight cement)
Introduction
Initiation
Propagation, Cracks
Corrosion versus time for predictionReinforced concrete prismsDifferent contaminationsDifferent environmental conditionsNDT electrochemical measurements Mathematical relation of corrosion CracksBouteiller et al, European Journal of Environmental and Civil Engineering 2012Bouteiller et al, Corrosion Reviews 2012Bouteiller et al, Construction and Building Materials 2016
Electrochemical repair treatments
Chalmers seminar - 13 September 2017 - V. Bouteiller 12 / 38
7-CI 4-CI 6-CIRealcalisation par courant imposé (CI)
11-CG 8-CG 10-CGRéalcalinisation par anode sacrificielle ( (CG)
� Phenolphtalein indicator : pink ring around the reba r (1,5 cm) but colour fade with time
� Concrete suspension: pH increases from 9 to 10-11 (CI) and from 9 à 11 (CG)
Chalmers seminar - 13 September 2017 - V. Bouteiller 22
� Efficient until 12 months
� For longer term, corrosion starts again
� Development of a specific cell for « in-situ » observa tions� Realcalisation is efficient but not durable
– Carbonated concrete• Green rust then lepidocrocite ( γ-FeOOH )
– During realcalisation• After 2h : (a) magnetite (Fe 3O4) and (b) brucite (Fe(OH) 2) and RV � reduction !• After 24h, (c) pure magnetite (d) pure brucite � Corrosion is halted as confirmed by the
intensities that remained stable
•
– 6 months after treatment• Oxydations magnetite in maghémite ( γ-Fe2O3) and brucite in ferroxyhite ( δ-FeOOH) �
corrosion starts again
� Confirmation of the corrosion with SEM observations
0 200 400 600 800 1000 1200
434
Ra
man
Inte
nsity
/a,u
,
Wavenumber/ cm -1
505
(a)
670
0 200 400 600 800 1000 1200
3600
422
Ram
an I
nten
sity
/a,u
,
Wavenumber/ cm -1
500
(b)
3580
200 400 600 800 1000 1200
Ra
man
Inte
nsity
/a,u
,
Wavenumber/ cm -1
(c)670
200 400 600 800 1000 1200
3400 3600
410
Ram
an I
nten
sity
/a,u
,
Wavenumber/ cm -1
498
(d)
3580
Chalmers seminar - 13 September 2017 - V. Bouteiller 23
Current projects
Chalmers seminar - 13 September 2017 - V. Bouteiller 24
Laboratory– Corrosion of reinforced concrete contaminated by ca rbonation and chloride
ions – Repair by ECE treatment
– Experimental and numerical studies of reinforced co ncrete structural elements damaged by corrosion
Field DeCoF-Ré Project– Reliability of a corrosion diagnosis of a bridge in a marine environment
(Pont de l'île de Ré) – Decisions
– Durability study on the piers of the ile de Ré Bridge
Chalmers seminar - 13 September 2017 - V. Bouteiller 25
� PhD defense Yolaine TISSIER, October 3, 2017
� PhD defense Olfa LOUKIL, October 17, 2017
� PhD defense Lucas BOURREAU, December 19, 2017
Objective: provide an indicator of survey instead o f alarm– Corrosion of reinforcement micro and macro scales + kinetic + models
26Chalmers seminar - 13 September 2017 - V. Bouteiller
� Project ANR MODEVIE
� APOS and CANOPEE Projects
Chalmers seminar - 13 September 2017 - V. Bouteiller 27
Concrete international / November 2010
The Cattenom nuclear power plant in eastern France was built during the 1980s.
Investigations of girders after 10 years exposure in 2008. In all cases, the quantity of chloride ions was found to be less than 0.1 g Cl– per 100 g of cement.
Chalmers seminar - 13 September 2017 - V. Bouteiller 28