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Open AccessArticle
Characteristics of Entrained Air Voids in Hardened Concrete with the Method of Digital Image Analysis Coupled with Schwartz-Saltykov Conversion
by Teemu OjalaORCID,Yanjuan Chen *,Jouni Punkki andFahim Al-Neshawy
Department of Civil Engineering, Aalto University, 02150 Espoo, Finland
*
Author to whom correspondence should be addressed.
Materials 2021, 14(9), 2439; https://doi.org/10.3390/ma14092439
Received: 5 April 2021 / Revised: 3 May 2021 / Accepted: 4 May 2021 / Published: 8 May 2021
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Abstract
This paper presents the characteristics of air void systems in hardened concrete with the method of digital image analysis (DIA) coupled with Schwartz-Saltykov (SS) conversion. The results indicate that the DIA method coupled with SS conversion estimates the air content with more accuracy than it would without SS conversion; the correlation between air content obtained from the DIA method, and that from the thin section (TS) method is as good as the correlation observed between the pressure saturation (PS) method and the TS method. It was also found that the DIA method shows a better correlation with the TS method when the spacing factor without SS conversion is considered, while both methods show poor correlations when the corresponding specific surface is considered. In addition, it indicates that the peak of three-dimensional size distribution (3-DSD) of air voids after SS conversion falls in smaller voids, and 3-DSD of air voids shifts to a narrow size range, in comparison with the 2-DSD without SS conversion; the shape of the 3-DSD air voids remains constant irrespective of the class widths. Increasing the number of classes can minimise the standard deviation in the estimation, however, it also results in a leap in voids volume density, which will influence the estimation of air content.
Open AccessArticle
Characteristics of Entrained Air Voids in Hardened Concrete with the Method of Digital Image Analysis Coupled with Schwartz-Saltykov Conversion
by Teemu OjalaORCID,Yanjuan Chen *,Jouni Punkki andFahim Al-Neshawy
Department of Civil Engineering, Aalto University, 02150 Espoo, Finland
*
Author to whom correspondence should be addressed.
Materials 2021, 14(9), 2439; https://doi.org/10.3390/ma14092439
Received: 5 April 2021 / Revised: 3 May 2021 / Accepted: 4 May 2021 / Published: 8 May 2021
Download Browse Figures Versions Notes
Abstract
This paper presents the characteristics of air void systems in hardened concrete with the method of digital image analysis (DIA) coupled with Schwartz-Saltykov (SS) conversion. The results indicate that the DIA method coupled with SS conversion estimates the air content with more accuracy than it would without SS conversion; the correlation between air content obtained from the DIA method, and that from the thin section (TS) method is as good as the correlation observed between the pressure saturation (PS) method and the TS method. It was also found that the DIA method shows a better correlation with the TS method when the spacing factor without SS conversion is considered, while both methods show poor correlations when the corresponding specific surface is considered. In addition, it indicates that the peak of three-dimensional size distribution (3-DSD) of air voids after SS conversion falls in smaller voids, and 3-DSD of air voids shifts to a narrow size range, in comparison with the 2-DSD without SS conversion; the shape of the 3-DSD air voids remains constant irrespective of the class widths. Increasing the number of classes can minimise the standard deviation in the estimation, however, it also results in a leap in voids volume density, which will influence the estimation of air content.
| Original language | English |
|---|---|
| Article number | 2439 |
| Pages (from-to) | 1-20 |
| Number of pages | 20 |
| Journal | Materials |
| Volume | 14 |
| Issue number | 9 |
| DOIs | |
| Publication status | Published - May 2021 |
Bibliographical note
Funding Information:Funding: This research was funded by Betonitekniikan alan yhteistyösopimus, grant number 700721. The authors would like to thank the Finnish concrete industry that include: Confedera-tion of Finnish Construction Industries RT (RM Concrete section), SBK Foundation, Finnsementti Oy, Finnish Transportation Agency (Väylavirasto), BASF Oy, Destia Oy that financially supported the work.
Funding Information:
This research was funded by Betonitekniikan alan yhteisty?sopimus, grant number 700721. The authors would like to thank the Finnish concrete industry that include: Confederation of Finnish Construction Industries RT (RM Concrete section), SBK Foundation, Finnsementti Oy, Finnish Transportation Agency (V?ylavirasto), BASF Oy, Destia Oy that financially supported the work.
Publisher Copyright:
© 2021 by the authors. Licensee MDPI, Basel, Switzerland.
Copyright:
Copyright 2021 Elsevier B.V., All rights reserved.