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Environmental Scanning Electron Microscopy as a Tool to Study Shrinkage Microcracks in Cement-Based Materials

Published online by Cambridge University Press:  10 February 2011

J. Bisschop  and
J.G.M. Van Mier
J. Bisschop
Affiliation:
Faculty of Civil Engineering and Geo-Sciences, Delft University of Technology, P.O. Box 5048, 2600 GA Delft, The Netherlands, J.Bisschop@ct.tudelft.nl
J.G.M. Van Mier
Affiliation:
Faculty of Civil Engineering and Geo-Sciences, Delft University of Technology, P.O. Box 5048, 2600 GA Delft, The Netherlands
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Abstract

In this paper a method is described to observe shrinkage microcracks on ‘wet’ specimen cross-sections of cement-based materials with Environmental Scanning Electron Microscopy (ESEM). A sample cooling device which can be used in the ESEM chamber was built to control the relative humidity above a microscope sample. The accuracy of measuring relative humidity is determined to be 5% at a sample temperature of 3°C. A microscope sample preparation method and a pump-down sequence of the ESEM-chamber, both without any drying of the sample, are described. Preliminary results show that in the studied mortar the visibility of shrinkage microcracks on a ‘wet’ specimen cross-section is low due to closure of microcracks by swelling of the cement paste.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 589 , 1999 , 141
Copyright
Copyright © Materials Research Society 2001

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References

1.Hwang, C.L. and Young, J.F.. Drying shrinkage of Portland cement pastes. I. Microcracking during drying. Cem. Con. Res. 14, 585 (1984).Google Scholar
2.Jensen, A.D. and Chatterji, S.. State of the art report on microcracking and lifetime of concrete - part 1. Mat. Struct. 29, 3 (1996).Google Scholar
3.Ringot, E., Ollivier, J.P., and Maso, J.C.. Characterisation of initial state of concrete with regard to microcracking. Cem. Con. Res. 17, 411 (1987).Google Scholar
4.Bascoul, A., Ollivier, J.P., and Turatsinze, A.. Discussion of the paper ‘Fracture zone presence and behaviour in mortar specimens’ by Krstulovic-Opara, N.. ACI Mat. J. 91 (5), 531 (1994).Google Scholar
5.Gran, H.C.. Fluorescent liquid replacement technique. A means of crack detection and water:binder ratio determination in high strength concretes. Cem. Con. Res. 25 (2), 1063 (1995).Google Scholar
6.Uwins, P.J.R., Environmental scanning electron microscopy. Mat. Forum. 18, 51 (1994).Google Scholar
7.Kjellsen, K.O. and Jennings, H.M.. Observations of microcracking in cement paste upon drying and rewetting by environmental scanning electron microscopy. Advn. Cem. Bas. Mat. 3, 14 (1996).Google Scholar
8.Bisschop, J. and Mier, J.G.M. van. Quantification of shrinkage microcracking in young mortar with fluorescence light microscopy and ESEM. Proc. 7th euroseminar on Microscopy Applied to Building Materials, June 1999, Delft, The Netherlands.Google Scholar
9.Penttala, V.. Freezing-induced strains and pressures in wet porous materials and especially in concrete mortars. Adv. Cem. Bas. Mat. 7, 8 (1998).Google Scholar
10.Cameron, R.E. and Donald, A.M.. Minimizing sample evaporation in the environmental scanning electron microscope. J. Micr. 173 (3), 227 (1994).Google Scholar
11.Griffin, B.J.. Hydrated specimen stability in the electroscan ESEM: specimen surface temperature variations and the limitations of specimen cooling. Proc. 50th annual meeting EMSA. San Francisco, 1306 (1992).Google Scholar
12.Reinhardt, H.W.. Beton als constructiemateriaal - eigenschappen en duurzaamheid. Delft University Press. 152 (1985).Google Scholar