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Microstructural Gradients in Cement Paste Around Aggregate Particles

Published online by Cambridge University Press:  21 February 2011

Karen L. Scrivener
Affiliation:
Imperial College, Dept. of Materials, London SW7 2BP, U.K.
Ellis M. Gartner
Affiliation:
W.R. Grace & Co., Research Division, Columbia, Maryland 21044, U.S.A.
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Abstract

The effectiveness of condensed silica fume as a strength enhancing additive in concrete has been attributed to its ability to modify the interfacial zone between paste and aggregate. This paper describes a microstructural investigation of this interface using backscattered electron (bse) imaging combined with quantitative image analysis.

Composite specimens were made in which a single piece of aggregate was embedded in cement paste. Granite, dolomite and garnet aggregates were used. After curing, the specimens were sectioned perpendicular to the surface of the aggregate particles and polished. The variation in porosity, amount of anhydrous material and calcium hydroxide (CH), with distance from the aggregate surface was measured. It was found that the porosity increases in the paste close to the interface, while the content of anhydrous grains decreases. No significant increase in CH content was found near the interface.

The results confirm the applicability of the bse - image analysis technique, but indicate that the interfaces in specimens prepared in this manner may not be representative of aggregate paste interfaces in concrete.

Type
Research Article
Copyright
Copyright © Materials Research Society 1988

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References

REFERENCES

1. Bentur, A., A. Goldman & M.D. Cohen, this proceedingsGoogle Scholar
2. Barnes, B.D., Diamond, S. & Dolch, W.L., J.Am.Ceram.Soc., 62, 2124, (1978).Google Scholar
3. Scrivener, K.L. & Pratt, P.L., Proc. 6th Int. Conf. on-Cement Microscopy, Alberquerque, New Mexico 1984 pp145155.Google Scholar
4. Scrivener, K.L., PhD Thesis, University of London, 1984 Google Scholar
5. Scrivener, K.L., in Research on the Manufacture and Use of Cements, ed Frohnsdorff, G. (Engineering Foundation, 1985) pp117119.Google Scholar
6. Scrivener, K.L. & Pratt, P.L., Proc 8th Int Cong. Chem. Cement, Rio de Janerio, 1986, Vol III, pp466471.Google Scholar
7. Farran, J., Revue des materiaux de construction, n° 490–491–492, 1956 Google Scholar
8. Grandet, J. & Ollivier, J.P., Proc 7th Int. Cong. Chem. Cement, Paris 1980, Vol III, ppVII85-89.Google Scholar
9. Grandet, J. & Ollivier, J.P., Proc 7th Int. Cong. Chem. Cement, Paris 1980, Vol III, ppVII63-68.Google Scholar
10. Monteiro, P.J.M. and Mehta, P.K., Cem. & Conc. Res. 15, 378–80, (1985).Google Scholar
11. Monteiro, P.J.M., Maso, J.C. and Ollivier, J.P., Cem. & Conc. Res. 15, 953958, (1985).Google Scholar
12. Scrivener, K.L. & Bentur, A., to be publishedGoogle Scholar
13. Goult, D. & Pratt, P.L., private communicationGoogle Scholar
14. Hadley, D.H., PhD thesis, Purdue University, USA, 1972.Google Scholar
15. Rosenberg, A.M. and Gaidis, J.M., presented at the 2nd. International Conference on The Use of Fly Ash, Silica Fume, Slag and Natural Pozzolans in Concrete, Madrid, Spain, April 1986.Google Scholar