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Characterization of airborne dust emissions from three types of crushed multi-walled carbon nanotube-enhanced concretes

Abrahamsson, Camilla LU ; Rissler, Jenny LU ; Kåredal, Monica LU orcid ; Hedmer, Maria LU orcid ; Suchorzewski, Jan ; Prieto, Miguel ; Chaudhari, Ojas Arun ; Gudmundsson, Anders LU and Isaxon, Christina LU (2024) In NanoImpact 34.
Abstract

Dispersing Multi-Walled Carbon Nanotubes (MWCNTs) into concrete at low (<1 wt% in cement) concentrations may improve concrete performance and properties and provide enhanced functionalities. When MWCNT-enhanced concrete is fragmented during remodelling or demolition, the stiff, fibrous and carcinogenic MWCNTs will, however, also be part of the respirable particulate matter released in the process. Consequently, systematic aerosolizing of crushed MWCNT-enhanced concretes in a controlled environment and measuring the properties of this aerosol can give valuable insights into the characteristics of the emissions such as concentrations, size range and morphology. These properties impact to which extent the emissions can be inhaled as... (More)

Dispersing Multi-Walled Carbon Nanotubes (MWCNTs) into concrete at low (<1 wt% in cement) concentrations may improve concrete performance and properties and provide enhanced functionalities. When MWCNT-enhanced concrete is fragmented during remodelling or demolition, the stiff, fibrous and carcinogenic MWCNTs will, however, also be part of the respirable particulate matter released in the process. Consequently, systematic aerosolizing of crushed MWCNT-enhanced concretes in a controlled environment and measuring the properties of this aerosol can give valuable insights into the characteristics of the emissions such as concentrations, size range and morphology. These properties impact to which extent the emissions can be inhaled as well as where they are expected to deposit in the lung, which is critical to assess whether these materials might constitute a future health risk for construction and demolition workers. In this work, the impact from MWCNTs on aerosol characteristics was assessed for samples of three concrete types with various amounts of MWCNT, using a novel methodology based on the continuous drop method. MWCNT-enhanced concretes were crushed, aerosolized and the emitted particles were characterized with online and offline techniques. For light-weight porous concrete, the addition of MWCNT significantly reduced the respirable mass fraction (RESP) and particle number concentrations (PNC) across all size ranges (7 nm - 20 μm), indicating that MWCNTs dampened the fragmentation process by possibly reinforcing the microstructure of brittle concrete. For normal concrete, the opposite could be seen, where MWCNTs resulted in drastic increases in RESP and PNC, suggesting that the MWCNTs may be acting as defects in the concrete matrix, thus enhancing the fragmentation process. For the high strength concrete, the fragmentation decreased at the lowest MWCNT concentration, but increased again for the highest MWCNT concentration. All tested concrete types emitted <100 nm particles, regardless of CNT content. SEM imaging displayed CNTs protruding from concrete fragments, but no free fibers were detected.

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author
; ; ; ; ; ; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
NanoImpact
volume
34
article number
100500
publisher
Elsevier
external identifiers
  • scopus:85186528171
  • pmid:38382676
ISSN
2452-0748
DOI
10.1016/j.impact.2024.100500
language
English
LU publication?
yes
id
1602283d-4586-4ac6-a929-b40f1bf93404
date added to LUP
2024-02-28 10:10:41
date last changed
2024-04-12 05:52:47
@article{1602283d-4586-4ac6-a929-b40f1bf93404,
  abstract     = {{<p>Dispersing Multi-Walled Carbon Nanotubes (MWCNTs) into concrete at low (&lt;1 wt% in cement) concentrations may improve concrete performance and properties and provide enhanced functionalities. When MWCNT-enhanced concrete is fragmented during remodelling or demolition, the stiff, fibrous and carcinogenic MWCNTs will, however, also be part of the respirable particulate matter released in the process. Consequently, systematic aerosolizing of crushed MWCNT-enhanced concretes in a controlled environment and measuring the properties of this aerosol can give valuable insights into the characteristics of the emissions such as concentrations, size range and morphology. These properties impact to which extent the emissions can be inhaled as well as where they are expected to deposit in the lung, which is critical to assess whether these materials might constitute a future health risk for construction and demolition workers. In this work, the impact from MWCNTs on aerosol characteristics was assessed for samples of three concrete types with various amounts of MWCNT, using a novel methodology based on the continuous drop method. MWCNT-enhanced concretes were crushed, aerosolized and the emitted particles were characterized with online and offline techniques. For light-weight porous concrete, the addition of MWCNT significantly reduced the respirable mass fraction (RESP) and particle number concentrations (PNC) across all size ranges (7 nm - 20 μm), indicating that MWCNTs dampened the fragmentation process by possibly reinforcing the microstructure of brittle concrete. For normal concrete, the opposite could be seen, where MWCNTs resulted in drastic increases in RESP and PNC, suggesting that the MWCNTs may be acting as defects in the concrete matrix, thus enhancing the fragmentation process. For the high strength concrete, the fragmentation decreased at the lowest MWCNT concentration, but increased again for the highest MWCNT concentration. All tested concrete types emitted &lt;100 nm particles, regardless of CNT content. SEM imaging displayed CNTs protruding from concrete fragments, but no free fibers were detected.</p>}},
  author       = {{Abrahamsson, Camilla and Rissler, Jenny and Kåredal, Monica and Hedmer, Maria and Suchorzewski, Jan and Prieto, Miguel and Chaudhari, Ojas Arun and Gudmundsson, Anders and Isaxon, Christina}},
  issn         = {{2452-0748}},
  language     = {{eng}},
  publisher    = {{Elsevier}},
  series       = {{NanoImpact}},
  title        = {{Characterization of airborne dust emissions from three types of crushed multi-walled carbon nanotube-enhanced concretes}},
  url          = {{http://dx.doi.org/10.1016/j.impact.2024.100500}},
  doi          = {{10.1016/j.impact.2024.100500}},
  volume       = {{34}},
  year         = {{2024}},
}