Performance of cementitious and alkali-activated mortars exposed to laboratory simulated microbially induced corrosion test

Khan, HA; Yasir, M; Castel, A

Performance of cementitious and alkali-activated mortars exposed to laboratory simulated microbially induced corrosion test

Khan, HA Yasir, M Castel, A

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Publisher:: ELSEVIER SCI LTD
Publication Type:: Journal Article
Citation:: Cement and Concrete Composites, 2022, 128
Issue Date:: 2022-04-01

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Field	Value	Language
dc.contributor.author	Khan, HA
dc.contributor.author	Yasir, M
dc.contributor.author	Castel, A https://orcid.org/0000-0003-1619-9643
dc.date.accessioned	2023-01-31T03:08:34Z
dc.date.available	2023-01-31T03:08:34Z
dc.date.issued	2022-04-01
dc.identifier.citation	Cement and Concrete Composites, 2022, 128
dc.identifier.issn	0958-9465
dc.identifier.issn	1873-393X
dc.identifier.uri	http://hdl.handle.net/10453/165660
dc.description.abstract	This research presents a laboratory simulated microbially induced corrosion (MIC) test method allowing to assess the performance of low calcium fly ash based geopolymer mortar (FA-GPm), alkali-activated slag-based mortar (AASm), sulphate resistant Portland cement mortar (SRPCm) and calcium aluminate cement mortar (CACm). This experiment runs for a period of six months in which sulphur oxidizing microbes (SOMs) (A. thiooxidans and T. intermedius) were grown in liquid media containing the thiosulphate ion. This test methodology aims to investigate the bacterial attachment phase (stage 2) followed by the initiation of acid attack (stage 3) of MIC. Lowering of the pH of liquid medium and the growth of microorganism was measured to evaluate the aggressiveness of this microbial environment. Visual, physical, chemical and microstructural investigations of mortars were performed over time to estimate the deteriorations. Ions leaching from the matrix and formation of sulphate (SO42−) was monitored using inductively coupled plasma mass spectroscopy (ICP-MS) and ion chromatography (IC), respectively. The results showed that the neutralization of CACm after exposure to biotic reactor was lesser compared to the other mortars, indicating its resistance towards biocorrosion. Moreover, formation of sulphuric acid (H2SO4) and the growth of SOMs showed its dependence on the type of mortar. Scanning electron microscopy (SEM) with energy-dispersive X-ray (EDX) spectroscopy was used to predict the depth of degradation and morphological variations at microstructural level. Patterns of deterioration and nucleation of minerals identified were similar to infield exposure, indicating the suitability of this testing method to simulate sewer biocorrosion.
dc.language	English
dc.publisher	ELSEVIER SCI LTD
dc.relation	Concrete Pipe Association of Australasia
dc.relation.ispartof	Cement and Concrete Composites
dc.relation.isbasedon	10.1016/j.cemconcomp.2022.104445
dc.rights	info:eu-repo/semantics/closedAccess
dc.subject	0904 Chemical Engineering, 0905 Civil Engineering, 1202 Building
dc.subject.classification	Building & Construction
dc.title	Performance of cementitious and alkali-activated mortars exposed to laboratory simulated microbially induced corrosion test
dc.type	Journal Article
utslib.citation.volume	128
utslib.for	0904 Chemical Engineering
utslib.for	0905 Civil Engineering
utslib.for	1202 Building
pubs.organisational-group	/University of Technology Sydney
pubs.organisational-group	/University of Technology Sydney/Faculty of Engineering and Information Technology
pubs.organisational-group	/University of Technology Sydney/Faculty of Engineering and Information Technology/School of Civil and Environmental Engineering
utslib.copyright.status	closed_access	*
dc.date.updated	2023-01-31T03:08:29Z
pubs.publication-status	Published
pubs.volume	128

Abstract:

This research presents a laboratory simulated microbially induced corrosion (MIC) test method allowing to assess the performance of low calcium fly ash based geopolymer mortar (FA-GPm), alkali-activated slag-based mortar (AASm), sulphate resistant Portland cement mortar (SRPCm) and calcium aluminate cement mortar (CACm). This experiment runs for a period of six months in which sulphur oxidizing microbes (SOMs) (A. thiooxidans and T. intermedius) were grown in liquid media containing the thiosulphate ion. This test methodology aims to investigate the bacterial attachment phase (stage 2) followed by the initiation of acid attack (stage 3) of MIC. Lowering of the pH of liquid medium and the growth of microorganism was measured to evaluate the aggressiveness of this microbial environment. Visual, physical, chemical and microstructural investigations of mortars were performed over time to estimate the deteriorations. Ions leaching from the matrix and formation of sulphate (SO42−) was monitored using inductively coupled plasma mass spectroscopy (ICP-MS) and ion chromatography (IC), respectively. The results showed that the neutralization of CACm after exposure to biotic reactor was lesser compared to the other mortars, indicating its resistance towards biocorrosion. Moreover, formation of sulphuric acid (H2SO4) and the growth of SOMs showed its dependence on the type of mortar. Scanning electron microscopy (SEM) with energy-dispersive X-ray (EDX) spectroscopy was used to predict the depth of degradation and morphological variations at microstructural level. Patterns of deterioration and nucleation of minerals identified were similar to infield exposure, indicating the suitability of this testing method to simulate sewer biocorrosion.

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http://hdl.handle.net/10453/165660