Aim of this work was to investigate the microstructure of the Interfacial Transition Zone (ITZ) between cement paste and aggregate in concrete utilizing Scanning Electron Microscope (SEM) in order to identify possible effects on the ITZ related to different recipes and production parameters. SEM is an important tool to carry out concrete, cement and aggregate microstructure characterization. SEM imaging facilitates identification of elements in concrete. Thanks to the higher spatial resolution, and the analytical capabilities, it allows to perform a materials-imaging-related analysis. Many information can thus be extracted from these data, such as composition, phase abundance and distribution. In particular, during the last years, backscattered electron imaging of polished surfaces became an important method for the study of cement and concrete microstructures. The technique has many advantages, as the possibility to visualize representative cross-sections over a wide range of magnifications and to correlate image contrast with materials composition (i.e. atomic number). Comparing the information acquired starting from SEM imaging and X-ray microanalysis, the complex microstructure of concrete can be analyzed and images with sub-micrometer definition acquired and processed, obtaining compositional, morphological and morphometric information allowing to understand and evaluate the mechanism affecting the interaction of the aggregates with the cement paste. A common image representative of the ITZ in concrete involves approximately a domain of about 30 μm surrounding each aggregate and showing, theoretically, an increase of the porosity at the aggregate interface. In order to study this transition zone, 12 different types of concrete mixtures were analyzed, characterized by different combination of cement and virgin/recycled aggregates. The influence of these aggregates (i.e. virgin and recycled) on the resulting concrete microstructure was studied. The significant morphological and overall textural characteristics (i.e. area with higher porosity around aggregate, micro-cracks, size of the crystals in the ITZ) were detected by SEM analysis. Image analysis and SEM investigation, obtained from different concrete samples, provided very interesting results due to the different porosity and the possible interactions between the aggregates and the cement paste.
Aim of this work was to investigate the microstructure of the Interfacial Transition Zone (ITZ) between cement paste and aggregate in concrete utilizing Scanning Electron Microscope (SEM) in order to identify possible effects on the ITZ related to different recipes and production parameters. SEM is an important tool to carry out concrete, cement and aggregate microstructure characterization. SEM imaging facilitates identification of elements in concrete. Thanks to the higher spatial resolution, and the analytical capabilities, it allows to perform a materials-imaging-related analysis. Many information can thus be extracted from these data, such as composition, phase abundance and distribution. In particular, during the last years, backscattered electron imaging of polished surfaces became an important method for the study of cement and concrete microstructures. The technique has many advantages, as the possibility to visualize representative cross-sections over a wide range of magnifications and to correlate image contrast with materials composition (i.e. atomic number). Comparing the information acquired starting from SEM imaging and X-ray microanalysis, the complex microstructure of concrete can be analyzed and images with sub-micrometer definition acquired and processed, obtaining compositional, morphological and morphometric information allowing to understand and evaluate the mechanism affecting the interaction of the aggregates with the cement paste. A common image representative of the ITZ in concrete involves approximately a domain of about 30 μm surrounding each aggregate and showing, theoretically, an increase of the porosity at the aggregate interface. In order to study this transition zone, 12 different types of concrete mixtures were analyzed, characterized by different combination of cement and virgin/recycled aggregates. The influence of these aggregates (i.e. virgin and recycled) on the resulting concrete microstructure was studied. The significant morphological and overall textural characteristics (i.e. area with higher porosity around aggregate, micro-cracks, size of the crystals in the ITZ) were detected by SEM analysis. Image analysis and SEM investigation, obtained from different concrete samples, provided very interesting results due to the different porosity and the possible interactions between the aggregates and the cement paste.
The ITZ in concrete with natural and recycled aggregates: Study of microstructures based on image and SEM analysis / Bonifazi, Giuseppe; Capobianco, Giuseppe; Serranti, Silvia; Eggimann, M.; Wagner, E.; Di Maio, F.; Lotfi, S.. - ELETTRONICO. - (2015), pp. 299-308. (Intervento presentato al convegno EMABM 2015 tenutosi a Delft, The Netherlands nel 17-19 June 2015).
The ITZ in concrete with natural and recycled aggregates: Study of microstructures based on image and SEM analysis
BONIFAZI, Giuseppe;CAPOBIANCO, GIUSEPPE;SERRANTI, Silvia;
2015
Abstract
Aim of this work was to investigate the microstructure of the Interfacial Transition Zone (ITZ) between cement paste and aggregate in concrete utilizing Scanning Electron Microscope (SEM) in order to identify possible effects on the ITZ related to different recipes and production parameters. SEM is an important tool to carry out concrete, cement and aggregate microstructure characterization. SEM imaging facilitates identification of elements in concrete. Thanks to the higher spatial resolution, and the analytical capabilities, it allows to perform a materials-imaging-related analysis. Many information can thus be extracted from these data, such as composition, phase abundance and distribution. In particular, during the last years, backscattered electron imaging of polished surfaces became an important method for the study of cement and concrete microstructures. The technique has many advantages, as the possibility to visualize representative cross-sections over a wide range of magnifications and to correlate image contrast with materials composition (i.e. atomic number). Comparing the information acquired starting from SEM imaging and X-ray microanalysis, the complex microstructure of concrete can be analyzed and images with sub-micrometer definition acquired and processed, obtaining compositional, morphological and morphometric information allowing to understand and evaluate the mechanism affecting the interaction of the aggregates with the cement paste. A common image representative of the ITZ in concrete involves approximately a domain of about 30 μm surrounding each aggregate and showing, theoretically, an increase of the porosity at the aggregate interface. In order to study this transition zone, 12 different types of concrete mixtures were analyzed, characterized by different combination of cement and virgin/recycled aggregates. The influence of these aggregates (i.e. virgin and recycled) on the resulting concrete microstructure was studied. The significant morphological and overall textural characteristics (i.e. area with higher porosity around aggregate, micro-cracks, size of the crystals in the ITZ) were detected by SEM analysis. Image analysis and SEM investigation, obtained from different concrete samples, provided very interesting results due to the different porosity and the possible interactions between the aggregates and the cement paste.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
