Hostname: page-component-78c5997874-8bhkd Total loading time: 0 Render date: 2024-11-10T08:50:50.504Z Has data issue: false hasContentIssue false

Microstructure and Microchemistry of Slag Cement Pastes

Published online by Cambridge University Press:  25 February 2011

A. M. Harrisson
Affiliation:
Blue Circle Industries PLC, Research Division, London Road, Greenhithe, Kent, DA9 9JQ, England
N. B. Winter
Affiliation:
Blue Circle Industries PLC, Research Division, London Road, Greenhithe, Kent, DA9 9JQ, England
H. F. W. Taylor
Affiliation:
Department of Chemistry, University of Aberdeen, Meston Walk, Old Aberdeen, AB9 2UE, Scotland
Get access

Abstract

Pastes of a portland cement (60%) blended with a granulated blastfurnace slag (40%) were examined, principally by SEM with EDX analysis. Reaction rims around slag particles and relicts of fully reacted slag particles had compositions compatible with mixtures, in varying proportions, of C-S-H having Si/Ca -0.62 and a phase of the hydrotalcite family having Al/Mg -0.38. Calculations taking into account relevant densities and water contents. indicated that replacement of the slag by its in situ hydration products entails little or no change in the numbers of Mg and O atoms per unit volume, but that substantial proportions of the Ca, Si and Al are released and an equivalent amount of H gained. In other respects, the microstructures qualitatively resembled those of pure portland cement pastes of similar ages, but less CH was formed and the C-S-H not formed in situ from the slag had a Si/Ca ratio of 0.56, higher than that of 0.50 to 0.53 found in the absence of slag. None of the individual phases in the slag cement pastes showed significant compositional variation with time in the 28 day to 14 month period studied. The relative amounts of Ca, Si and Al expelled from the slag are such that, in order to form C-S-H and AFm phase, more Ca is required. It is obtained partly at the expense of CH formation, and partly through increase in the Si/Ca ratio of the C-S-H formed from the clinker phases. Mass balance, volume composition and bound water content were calculated for the 14 month old paste and compared with corresponding results for the pure portland cement.

Type
Research Article
Copyright
Copyright © Materials Research Society 1987

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

1. Cesareni, C. and Frigione, G., in Proc. 5th Int. Symp. Chem. Cem., Tokyo, 1968 4, 237247 (1969).Google Scholar
2. Kondo, R. and Ohsawa, S., in Proc. 5th Int. Symp. Chem. Cem., Tokyo, 1968, 1, 255269 (1969).Google Scholar
3. Daimon, M., in Proc. 7th Int. Congr. Chem. Cem, Paris, 1980, 1, III–2/1 to III2/9 (1980).Google Scholar
4. Regourd, M., in Proc. 7th Int. Congr. Chem. Cem, Paris, 1980, 1, III2/10 to III-2/26 (1980).Google Scholar
5. Regourd, M., Mortureux, B., Gautier, E., Hornain, H. and Volant, J., in Proc. 7th Int. Congr. Chem. Cem, Paris, 1980, 2, III105 to III-111 (1980).Google Scholar
6. Uchikawa, H., in Proc. 8th Int. Congr. Chem. Cem., Rio, 1986, 1, 249280 (1986).Google Scholar
7. Regourd, M., Mortureux, B. and Hornain, H., in Proc. 1st Int. Conf. on the Use of Fly Ash, Silica Fume and Other Mineral By-Products in Concrete, Montebello, 1983 (ACI SP 79, 1983) 2, pp. 847865.Google Scholar
8. Taylor, H.F.W., Mohan, K. and Moir, G.K., J. Amer. Ceram. Soc. 68, 685 (1985).Google Scholar
9. Tanaka, H., Totani, Y. and Saito, Y., in Proc. 1st Int. Conf. on the Use of Fly Ash, Silica Fume and Other Mineral By-Products in Concrete, Montebello, 1983 (ACI SP 79, 1983) 2, pp. 963977.Google Scholar
10. Kuhle, K. and Ludwig, U., Sprechsaal Keram., Glas, Email, Silik. 105, 421 (1972).Google Scholar
11. Mascolo, G., Nastro, A. and Sabatelli, V., Cemento 74, 45 (1977).Google Scholar
12. Taylor, H.F.W., Mohan, K. and Moir, G.K., J. Amer. Ceram. Soc. 68, 680 (1985).Google Scholar
13. Harrisson, A., Winter, N.B. and Taylor, H.F.W., in Proc. 8th Int. Congr. Chem. Cem., Rio, 1986, 4, 170175 (1986).Google Scholar
14. Harrisson, A.M., Taylor, H.F.W. and Winter, N.B., Cem. Concr. Res. 15, 775780 (1985).Google Scholar
15. Day, R.L., Cem. Concr. Res. 11, 341 (1981).Google Scholar
16. Jones, F.E., J. Soc. Chem. Ind. 51, 29 (1940).Google Scholar
17. Taylor, H.F.W., J. Amer. Ceram. Soc. 69, 464 (1986).Google Scholar
18. Koritnig, S. and Susse, P., Tschermaks Mineral. Petrogr. Mitt. 22, 79 (1975).Google Scholar
19. Taylor, H.F.W., Materials Science Monographs, 28A (Reactivity of Solids, Part A), 39 (1985).Google Scholar
20. Taylor, H.F.W., in Microstructural Development During Hydration of Cement, edited by Struble, L.J. and Brown, P.W., Mat. Res. Soc. Symp. Proc. Vol.87 (Materials Research Society, Pittsburgh, 1987).Google Scholar
21. Moir, G.K., in Proc. of the 1985 Beijing International Symposium on Cement and Concrete, (China Building Industry Press, 1986) 1, pp. 366379.Google Scholar