The effect of exposure on the autogenous self-healing of Ordinary Portland cement mortars
Document identifier: oai:DiVA.org:ltu-76526
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10.3390/ma12233926Keyword: Engineering and Technology,
Civil Engineering,
Infrastructure Engineering,
Teknik och teknologier,
Samhällsbyggnadsteknik,
Infrastrukturteknik,
Autogenous self-healing,
Cementitious materials,
Cracking,
Exposure,
Microstructure,
Calcium phosphate,
Byggmaterial,
Building MaterialsPublication year: 2019Relevant Sustainable Development Goals (SDGs):
The SDG label(s) above have been assigned by OSDG.aiAbstract: Exposure conditions are critical for the autogenous self-healing process of Portland cement based binder matrixes. However, there is still a significant lack of fundamental knowledge related to this factor. The aim of this paper was to investigate and understand the effects of various potentially applicable curing solutions on the efficiency of the crack closure occurring both superficially and internally. Four groups of exposures were tested, including exposure with different water immersion regimes, variable temperatures, application of chemical admixtures, and use of solutions containing micro particles. The self-healing process was evaluated externally, at the surface of the crack, and internally, at different crack depths with the use of optical and scanning electron microscopes (SEM). The phase identification was done with an energy dispersive spectrometer combined with the SEM. The results showed very limited self-healing in all pure water-based exposures, despite the application of different cycles, temperatures, and water volumes. The addition of a phosphate-based retarding admixture demonstrated the highest crack closure, both internally and externally. The highest strength recovery and a very good crack closure ratio was achieved in water exposure containing micro silica particles. The main phase observed on the surface was calcium carbonate, and internally, calcium silicate hydrate, calcium carbonate, and calcium phosphate compounds. Phosphate ions were found to contribute to the filling of the crack, most likely by preventing the formation of a dense shell composed of hydration phases on the exposed areas by crack unhydrated cement grains as well as by the additional precipitation of calcium and phosphate-based compounds. The micro sized silica particles presumably served as nucleation sites for the self-healing products growth. Changes in the chemical composition of the self-healing material were observed with a distance from the surface of the specimen.
Authors
Magdalena Rajczakowska
Luleå tekniska universitet; Byggkonstruktion och brand
Other publications
>>
Karin Habermehl-Cwirzen
Luleå tekniska universitet; Byggkonstruktion och brand
Other publications
>>
Hans Hedlund
Luleå tekniska universitet; Byggkonstruktion och brand; Skanska, Stockholm, Sweden
Other publications
>>
Andrzej Cwirzen
Luleå tekniska universitet; Byggkonstruktion och brand
Other publications
>>
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header:
identifier: oai:DiVA.org:ltu-76526
datestamp: 2021-04-19T12:41:05Z
setSpec: SwePub-ltu
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recordContentSource: ltu
recordCreationDate: 2019-10-28
identifier:
http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-76526
10.3390/ma12233926
31783574
2-s2.0-85075858886
titleInfo:
@attributes:
lang: eng
title: The effect of exposure on the autogenous self-healing of Ordinary Portland cement mortars
abstract: Exposure conditions are critical for the autogenous self-healing process of Portland cement based binder matrixes. However there is still a significant lack of fundamental knowledge related to this factor. The aim of this paper was to investigate and understand the effects of various potentially applicable curing solutions on the efficiency of the crack closure occurring both superficially and internally. Four groups of exposures were tested including exposure with different water immersion regimes variable temperatures application of chemical admixtures and use of solutions containing micro particles. The self-healing process was evaluated externally at the surface of the crack and internally at different crack depths with the use of optical and scanning electron microscopes (SEM). The phase identification was done with an energy dispersive spectrometer combined with the SEM. The results showed very limited self-healing in all pure water-based exposures despite the application of different cycles temperatures and water volumes. The addition of a phosphate-based retarding admixture demonstrated the highest crack closure both internally and externally. The highest strength recovery and a very good crack closure ratio was achieved in water exposure containing micro silica particles. The main phase observed on the surface was calcium carbonate and internally calcium silicate hydrate calcium carbonate and calcium phosphate compounds. Phosphate ions were found to contribute to the filling of the crack most likely by preventing the formation of a dense shell composed of hydration phases on the exposed areas by crack unhydrated cement grains as well as by the additional precipitation of calcium and phosphate-based compounds. The micro sized silica particles presumably served as nucleation sites for the self-healing products growth. Changes in the chemical composition of the self-healing material were observed with a distance from the surface of the specimen.
subject:
@attributes:
lang: eng
authority: uka.se
topic:
Engineering and Technology
Civil Engineering
Infrastructure Engineering
@attributes:
lang: swe
authority: uka.se
topic:
Teknik och teknologier
Samhällsbyggnadsteknik
Infrastrukturteknik
@attributes:
lang: eng
topic: autogenous self-healing
@attributes:
lang: eng
topic: cementitious materials
@attributes:
lang: eng
topic: cracking
@attributes:
lang: eng
topic: exposure
@attributes:
lang: eng
topic: microstructure
@attributes:
lang: eng
topic: calcium phosphate
@attributes:
lang: swe
authority: ltu
topic: Byggmaterial
genre: Research subject
@attributes:
lang: eng
authority: ltu
topic: Building Materials
genre: Research subject
language:
languageTerm: eng
genre:
publication/journal-article
ref
note:
Published
4
Validerad;2019;Nivå 2;2019-12-09 (johcin)
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authority: ltu
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Rajczakowska
Magdalena
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Luleå tekniska universitet
Byggkonstruktion och brand
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Karin
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Luleå tekniska universitet
Byggkonstruktion och brand
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Luleå tekniska universitet
Byggkonstruktion och brand
Skanska Stockholm Sweden
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Byggkonstruktion och brand
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originInfo:
dateIssued: 2019
publisher: MDPI
relatedItem:
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titleInfo:
title: Materials
identifier:
1996-1944
1996-1944
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@attributes:
type: volume
number: 12
@attributes:
type: issue
number: 23
@attributes:
type: artNo
number: 3926
physicalDescription:
form: print
typeOfResource: text