Corrosion and protection in reinforced concrete Pulse cathodic protection:

an improved cost-effective alternative

Proefschrift

ter verkrijging van de graad van doctor

aan de Technische Universiteit Delft,

op gezag van de Rector Magnificus prof. dr. ir. J.T. Fokkema,

voorzitter van het College voor Promoties,

in het openbaar te verdedigen

op maandag 11 juni 2007 om 10:00 uur

door

Dessislava Atanassova KOLEVA

Master of Science aan de University of Metallurgy,

Chemical Technology and Engineering, Sofia, Bulgarije

geboren te Sofia, Bulgarije

Dit proefschrift is goedgekeurd door de promotoren:

Prof. dr. ir. K.van Breugel

Prof. dr. J.H.W. de Wit

Samenstelling promotiecommissie:

Rector Magnificus Voorzitter

Prof. dr. ir. K. van Breugel Technische Universiteit Delft, promotor

Prof. dr. ir. J. H. W. de Wit Technische Universiteit Delft, promotor

Dr. ir. A. L. A. Fraaij Technische Universiteit Delft, co-promotor

Prof. dr. B. Isecke Bundesanstalt für Materialforschung und Prüfung, Berlin, DE

Prof. dr. D. Scantlebury The University of Manchester, UK

Prof. dr. ir. S. van der Zwaag Technische Universiteit Delft

Dr. ir. E. van Westing

Netherlands Institute for Metals Research (NIMR), Delft

Prof. dr. ir. F.S.K. Bijlaard Technische Universiteit Delft, reserve lid

Cover design: MSc.Arch. Vesselin A. Kolev

Cover picture: Micrographs (light microscope and ESEM) of corrosion products on the steel surface.

Corrosion and protection in reinforced concrete. Pulse cathodic protection: an improved, cost-

effective alternative/ D. A. Koleva

PhD Thesis Delft University of Technology

Keywords: corrosion, cathodic protection, reinforced concrete

All rights reserved. No part of the material protected by this copyright notice may be reproduced or utilized in

any form or by any means, electronic or mechanical, including photocopying, recording or by any information

storage and retrieval system, without written permission from the copyright owner.

Copyright @2007 by Dessislava A. Koleva

Printed in the Netherlands

ISBN 978-90-9021924-0

Part of this research was financially supported by the European Commission, EU Contract No: G5TR-CT-2001-00067.

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ACKNOWLEDGMENTS

This thesis could not have been produced without the financial and technical support of the Section

“Materials and Environment” and the “Microlab” within the Faculty of Civil Engineering at Delft University

of Technology; Van der Heide CP&CE, Kollum, The Netherlands and the EU contribution in the frame of a

Marie Curie grant. The support and help of these institutions is gratefully acknowledged.

A PhD thesis is never only the work of the PhD candidate, but is accompk lished through the efforts of many

people, who contribute to the successful end of the project. Therefore I woff uld like to express my gratitude to

all, who contributed in different ways to the completion of my thesis.

At first I would like to acknowledge my late promotor Prof. Ch. F. Hendriks, who gave me the courage and

confidence to start with this “concrete” project in the Netherlands. I will always value his guidance and

support when it came to choose the complicated “blend” of electrochemistry and concrete material science, as

well as his concepts on sustainability, but also on life in general.

Back in 2003, I started the initial period of my research with dr.ir. Alex Fraaij, who was my daily supervisor

and continued his guidance and encouragement throughout the whole project. I would like to thank him for all

his efforts and especially his help, when it came to “translating” our research ideas and research plans to theaa

industrial partner in the project, Van der Heide CP&CE.

I am gratefully indebted to my promotor, Prof. Klaas van Breugel for his willingness to become my promotor,

after the demise of Prof. Hendriks. I am very much grateful for his trust and confidence in my research, for ff

his continuous support and encouragement. Many thanks for our valuable discussions, which always gave me

the motivation to look from a “different angle”, to plan a new and different experiment or to carry out some

extra research, which finally led to an interesting exploration.

A special paragraph and special thanks goes to my promotor Prof. Hans de Wit. I am very much grateful for

his willingness to be my promotor in the second part of my research. Without his involvement, without his

guidance and expertise, the completion of this project would have not been possible. I would like to express

my sincere gratitude for his valuable encouragement, for the always inspiring discussions and for his really

continuous support. Our working sessions always gave me motivation and the needed confidence in the

research outcomes. Prof. de Wit, thanks a lot for your efforts and help!

I would like to thank (in no particular order) to a number of people, who contributed to the successful

completion of the project: Kees van Beek and Paul Vermeulen, without their help on our “special devises” the

innovative pulse Cathodic protection was not going to be studied and established, so thanks a lot! My former

colleagues, Plonia Wardenier and Rinus van Maasakkers, I really appreciate their efforts and valuable

contribution in many practical aspects of the experimental work. Many thanks to Marijke van der Veen for

her help in the administrative issues, related to my work. Special thanks goes to my former colleague and

friend Jing Hu for her valuable cooperation, the numerous discussions on how to correlate “my” corrosion

and “her” modeling of the concrete pore structure, which finally resulted in several nice papers. I would also

like to thank my colleague Oguzhan Copuroglu for his help both with experimental issues, as well as for our

scientific collaboration. I am thankful for the fruitful discussions (on both scientific and “just life” issues)

Kees van Beek and Paul Vermeulen,

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with my former and present colleagues, especially Deepa Nair, Claudia Basta, Dwinita Larasati, Peter

Angelov, Ye Guang, Zhanqi Guo, Xialong Zhang, Zeeshan Lodhi and Premendra.

I would like to thank my former colleagues from the company Van der Heide for their support and efforts to

make my initial stay in Friesland as pleasant and fruitful as possible, special thanks goes to Mr. Henk

Timmers, Mr. Ed Pols, Gaatze, Bart, Klaas, Adrie, Hannie, Maaike en Tettsje.

I would like to express my gratitude to Prof. Ivan Juchnovski, the head of the Bulgarian Academy of Sciences

and my former boss, who supported my decision of starting this project and encouraged me to take the

opportunity to complete this PhD in the Netherlands. Special thanks to Emilia Hristoskova, who was always

there with a solution for the administrative issues in the course of these four years. I would also like to thank

my former supervisors Prof. Raicho Raicheff and Prof. Georgy Raichevski, as well as my colleagues Dr.

Nikolai Boshkov, Vassil Buchvarov, Hristo Kolev, Neli Tsvetkova. Their long distance help and contribution

in one or another way to practical issues and research questions is gratefully acknowledged.

Many thanks to my dear friends Eli Trifonova and Peppa Sassin for their lasting friendship and their long

distance support.

Last, but certainly not least, I wish to thank my family for their love, encouragement and support, especially

during these years. My endless love and respect goes to my parents, and to my brother for always being there

for me, for always giving me the motivation and support in difficult moments. This project would not have

been completed without the love and understanding of my husband Evgeniy and our daughter Annie. Thank

you for your patience! My dearest Annie, thank you for being strong and motivated to accomplish your goals

and to cope with the difficulties of your age, while receiving so little support during these four years from

your always busy or absent mother, thank you for your love and understanding.

Dessi Koleva

Den Haag, May 2007

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Conference and proceedings papers

1. Koleva DA., Hu J., Van Breugel K., De Wit J.H.W., Boshkov N., Conventional and pulse CP of

reinforced concrete: Electrochemical approach and microstructural investigation, ECS Trans. 1 (4), 287-

298 (2006)

2. Koleva DA, K.van Breugel, J.H.W.de Wit, N.Boshkov, A.Fraaij, Application of Electrochemical

Impedance Spectroscopy in the Evaluation of Corrosion and Cathodic Protection in Reinforced Concrete,

ECS Trans. 2, (17), 51-61 (2007)

3. Koleva DA, K.van Breugel, J.H.W.de Wit, N.Boshkov, A.Fraaij, Composition and morphology of

product layers in the steel/cement paste interface in conditions of corrosion and cathodic protection in

reinforced concrete ECS Trans. 2, (9), pp127-136 (2007)

4. Koleva DA, Hu J, Fraaij ALA, Durable building technology benefiting electrochemical methods as att

preventive. In: Brebbia CA, DeGiorgi VG, Adey RA (eds.), Simulation of Electrochemical Processes,

May 2-4, Spain: Wit Press, pp. 87-98 (2005)

5. Koleva DA, Fraaij ALA, Hu J, Boshkov N, Steel corrosion in mortar specimens deteriorated by chloride

ingress: Electrochemical study using AC and DC methods and microscopic analysis of the steel/mortar

interface, 207th Spring meeting, ECS, May 15-20, Quebec, Canada (2005)

6. Koleva DA, Hu J, Fraaij ALA, Stroeven P, Influences of chloride ions on plain and reinforced mortars

investigated by combined microstructure and electrochemical approaches, Eurocorr’05, September 4-8,

Lisbon, Portugal, pp. 315 (2005)

7. Koleva DA, Hu J, Fraaij ALA, de Wit JHW, Overkamp P, Electrochemical and microstructural

investigations on steel reinforcement in mortars subjected to cathodic protection, 16th International

Corrosion Congress, September 19-24, China, pp. 491 (2005)

8. Hu J, Koleva DA, Stroeven P, Efficiency of cathodic protection in retarding corrosion-induced cracking

of mortars subjected to aggressive environments, 16th International Corrosion Congress, September 19-

24, China, pp. 264 (2005)

10. Koleva DA, Hu J, van Breugel K, de Wit JHW, Boshkov N, Conventional and pulse cathodic protection

on reinforced concrete: electrochemical approach and microstructural investigations,aa 208th Meeting of the

Electrochemical Society,yy Los Angeles, USA (2005)

11. Koleva DA, K.van Breugel, J.H.W.de Wit, A.Fraaij, An improved method for cathodic protection in

reinforced concrete, “11th

Middle East Corrosion Congress”, Bahrain , Feb 26th -Mar 1st, Eds.: F.M.Al

Faqeer, N.Khan (2006)

12. Koleva DA, K.van Breugel, J.H.W.de Wit, N.Boshkov, A.Fraaij, Composition and morphology of

product layers in the steel/cement paste interface in conditions of corrosion and cathodic protection in

reinforced concrete, 209th

Meeting of the ECS, Denver, USA, 7-12 May, MA 601, 328 (2006)

13. Koleva DA, K.van Breugel, J.H.W.de Wit, N.Boshkov, A.Fraaij, Application of Electrochemical

Impedance Spectroscopy in the Evaluation of Corrosion and Cathodic Protection in Reinforced Concrete,

209th

Meeting of the ECS, Denver, USA, 7-12 May, MA 601, 1186 (2006)

14. Koleva DA, K.van Breugel, JHW de Wit, J.Hu, Corrosion and CP in Reinforced Mortar: Monitoring

and Modeling Using Electrochemical and Microstructural Approaches, “Concrete Solutions II”, St.Malo,

France (2006)

9. Koleva DA, Hu J, Fraaij A, van Beek K, Concrete behavior under pulse and conventional CP current, , , j , , p

Proceedings of Australian Corrosion Association, CAP05,Gold Coast, Australia (2005)

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15. Tsvetkova, N., Petrov, P, Boshkov, N,Koleva, DA, & Raichevski, G, Application of some block co-

polymer aggregates for the preparation of zinc nanocomposite galvanic coatings and investigation of their

properties. In D Stoychev & E Valova (Eds.), Nanostructured materials in electroplating (pp. 178-181).

Bulgaria: St.Kliment Ohridski University Press (2006)

16. Boshkov, N, Petrov, P, Tsvetkova, N., Raichevski, G., Raicheff, R., Tsvetanov, Ch., & Koleva, DA,

Electrochemical corrosion investigations of nanostructured composite coatings based on zinc and zinc-

cobalt alloys. In D Stoychev & E Valova (Eds.), Nanostructured materials in electroplating (pp. 182-185).

Bulgaria: St.Kliment Ohridski University Press (2006)

17. Koleva DA,K.van Breugel, JHW de Wit, Corrosion and CP in reinforced concrete, 6th

International

PhD Symposium, Zurich, publisher ETH Zurich (2006)

18. Koleva DA, Hu J, Stroeven P, Microstructure alterations underlying electrochemical process of

chloride-induced corrosion, “Brittle Matrix Composites VIII”, Warsaw, Poland, Sept.’06, pp 572-580

(2006)

19. Koleva, JHW de Wit, K.van Breugel, A.Fraaij, Electrochemical phenomena of corrosion and protection

in reinforced concrete: breakdown to multiphase interface structures, Eurocorr’06, 25th -28th Sept.,

Maastricht, The Netherlands, publisher EFC, event no:280 (2006)

20. Koleva DA, K.van Breugel, JHW de Wit, V.Bachvarov, H.Kolev, Electrochemical measurements on

previously conditioned in concrete reinforcing steel in cement extract solutions, 210th meeting ECS,

Cancun, MX, (2006)

21. Koleva DA, O.Copuroglu, K.van Breugel, JHW de Wit, Bond strength degradation due to impressed

current CP in reinforced concrete, 210th meeting ECS, Cancun, MX (2006)

22. Koleva DA, Copuroglu O, van Breugel K, de Wit JHW, Microscopical investigation of hydration and

corrosion products in reinforced concrete, 11th

Euroseminar Applied to Building Materials, Porto,

Portugal, 5-9 June (2007).