The "mica crisis" in Donegal, Ireland – a case of internal sulfate attack?

Andreas Leemann; Barbara  Lothenbach; Beat  Münch; Thomas Campbell; Paul Dunlop

doi:10.1016/j.cemconres.2023.107149

The "mica crisis" in Donegal, Ireland – a case of internal sulfate attack?

Andreas Leemann, Barbara Lothenbach, Beat Münch, Thomas Campbell, Paul Dunlop

Research output: Contribution to journal › Article › peer-review

18 Citations (Scopus)

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Abstract

In County Donegal, northwest Ireland, thousands of homes built with concrete blocks show an increasing degree of severe structural defects attributed to high mica content in the aggregates. Consequently, the problem is popularly known as the “Mica Crisis”. In this project the concrete blocks of four affected homes are investigated by microstructural and chemical analysis combined with thermodynamic modelling. Apart from mica, the aggregates contain iron sulphides mainly in the form of pyrrhotite. The sulfur content of the aggregates considerably exceeds the limit value defined by the European standard for concrete aggregates (EN 12620). The results of the microstructural analysis coupled with thermodynamic modelling demonstrate that the concrete suffers from internal sulfate attack triggered by pyrrhotite oxidation. The comparison of the results of this investigation with the data collected by chartered engineers on almost hundred damaged homes shows that the four investigated cases are representative of the situation in Donegal.

Original language	English
Article number	107149
Pages (from-to)	1-14
Number of pages	14
Journal	Cement and Concrete Research
Volume	168
Issue number	June 2023
Early online date	15 Mar 2023
DOIs	https://doi.org/10.1016/j.cemconres.2023.107149
Publication status	Published online - 15 Mar 2023
Event	The Science and Societal Impacts of Defective Concrete - Atlantic Technical University, Donegal & Ulster University, Magee Campus, Letterkenny & Derry, Ireland Duration: 15 Nov 2022 → 17 Nov 2022 https://www.eventbrite.ie/e/the-science-and-societal-impacts-of-defective-concrete-tickets-443321886697

Bibliographical note

Funding Information:
The authors would like to thank the owners of the four investigated homes for permitting the extraction of cores and providing the test reports. Frank Winnefeld is acknowledged for the XRD analysis and Pietro Lura for reviewing the manuscript. Additionally, the authors would like to thank the two anonymous peer reviewers for their work.

Publisher Copyright:
© 2023 Elsevier Ltd

Keywords

concrete
pyrrhotite
internal sulfate attack
microstructure
cracking
Pyrrhotite
Cracking
Concrete
Internal sulfate attack
Microstructure

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Access to Document

10.1016/j.cemconres.2023.107149Licence: CC BY

Leemann_et_al_2023Final published version, 11.4 MBLicence: CC BY

Cite this

@article{dbb478550966410485cd64de231f0e0a,

title = "The {"}mica crisis{"} in Donegal, Ireland – a case of internal sulfate attack?",

abstract = "In County Donegal, northwest Ireland, thousands of homes built with concrete blocks show an increasing degree of severe structural defects attributed to high mica content in the aggregates. Consequently, the problem is popularly known as the “Mica Crisis”. In this project the concrete blocks of four affected homes are investigated by microstructural and chemical analysis combined with thermodynamic modelling. Apart from mica, the aggregates contain iron sulphides mainly in the form of pyrrhotite. The sulfur content of the aggregates considerably exceeds the limit value defined by the European standard for concrete aggregates (EN 12620). The results of the microstructural analysis coupled with thermodynamic modelling demonstrate that the concrete suffers from internal sulfate attack triggered by pyrrhotite oxidation. The comparison of the results of this investigation with the data collected by chartered engineers on almost hundred damaged homes shows that the four investigated cases are representative of the situation in Donegal.",

keywords = "concrete, pyrrhotite, internal sulfate attack, microstructure, cracking, Pyrrhotite, Cracking, Concrete, Internal sulfate attack, Microstructure",

author = "Andreas Leemann and Barbara Lothenbach and Beat M{\"u}nch and Thomas Campbell and Paul Dunlop",

note = "Funding Information: The authors would like to thank the owners of the four investigated homes for permitting the extraction of cores and providing the test reports. Frank Winnefeld is acknowledged for the XRD analysis and Pietro Lura for reviewing the manuscript. Additionally, the authors would like to thank the two anonymous peer reviewers for their work. Publisher Copyright: {\textcopyright} 2023 Elsevier Ltd; The Science and Societal Impacts of Defective Concrete ; Conference date: 15-11-2022 Through 17-11-2022",

year = "2023",

month = mar,

day = "15",

doi = "10.1016/j.cemconres.2023.107149",

language = "English",

volume = "168",

pages = "1--14",

journal = "Cement and Concrete Research",

issn = "0008-8846",

publisher = "Elsevier",

number = "June 2023",

url = "https://www.eventbrite.ie/e/the-science-and-societal-impacts-of-defective-concrete-tickets-443321886697",