TY - GEN
T1 - Role of thresholding to determine size of interfacial transition zone
AU - Basheer, P. A.Muhammed
AU - Basheer, Lulu
AU - Lange, David
AU - Long, Adrian
N1 - Funding Information:
The concrete specimens were prepared by Dr. G. Henderson in School of Civil Engineering and the samples for the BSE imaging were prepared Dr. P. Warke in School of Geosciences. This and the facilities provided by both the School of Civil Engineering at The Queen's University of Belfast and Department of Civil Engineering at the University of Illinois at Urbana-Champaign is gratefully acknowledged.
Publisher Copyright:
© 2000 American Concrete Institute. All rights reserved.
PY - 2000/1/1
Y1 - 2000/1/1
N2 - Concrete may be considered a three phase material, consisting of cement matrix, aggregate and the interfacial transition zone (ITZ). The ITZ is studied usually by collecting backscattered electron (BSE) images of polished samples of concrete and by carrying out a quantitative analysis of these images. This technique makes use of the contrast between pores and cement hydrates to analyse the microstructure. Once the images are collected, grey level thresholding is used to segment regions associated with capillary porosity. The size of the ITZ is determined using this data. Different techniques have been suggested to minimise errors introduced at this stage of the analysis. The authors have carried out an investigation on 17 different concrete mixtures in an attempt to assess the role of threshold values on the size of the ITZ. The analysis was carried out using different threshold values and the thickness of the ITZ was determined for each of these values. The results indicated that the size of the transition zone is not affected by the range of threshold values used. However, the porosity of both the ITZ and the bulk cement paste varied with different threshold values. The paper proposes a method which can be used to determine a reliable threshold value.
AB - Concrete may be considered a three phase material, consisting of cement matrix, aggregate and the interfacial transition zone (ITZ). The ITZ is studied usually by collecting backscattered electron (BSE) images of polished samples of concrete and by carrying out a quantitative analysis of these images. This technique makes use of the contrast between pores and cement hydrates to analyse the microstructure. Once the images are collected, grey level thresholding is used to segment regions associated with capillary porosity. The size of the ITZ is determined using this data. Different techniques have been suggested to minimise errors introduced at this stage of the analysis. The authors have carried out an investigation on 17 different concrete mixtures in an attempt to assess the role of threshold values on the size of the ITZ. The analysis was carried out using different threshold values and the thickness of the ITZ was determined for each of these values. The results indicated that the size of the transition zone is not affected by the range of threshold values used. However, the porosity of both the ITZ and the bulk cement paste varied with different threshold values. The paper proposes a method which can be used to determine a reliable threshold value.
KW - Aggregates
KW - Cement matrix
KW - Image analysis
KW - Microstructure
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M3 - Conference contribution
AN - SCOPUS:84995977471
T3 - American Concrete Institute, ACI Special Publication
SP - 165
EP - 186
BT - High-Performance Concrete
A2 - Russell, H.G.
PB - American Concrete Institute
T2 - High-Performance Concrete Research to Practice 1999
Y2 - 14 March 1999 through 19 March 1999
ER -