Contribution to the Concrete Strength versus Water-Cement Ratio Relationship
Publication: Journal of Materials in Civil Engineering
Volume 20, Issue 7
Abstract
The first rarely mentioned fundamental assumptions for the strength versus water-cement ratio relationship are discussed, namely, that: (a) the strength of structural concrete is controlled by the strength of the cement paste in it; (b) the strength of a cement paste depends strongly on the porosity in it; and (c) the porosity (capillary) is a function of the water-cement ratio. This is the foundation of the relationship between concrete strength and water-cement ratio. Numerous empirical formulas, so-called strength formulas, have been developed for this relationship; the Abrams’ formula for instance. These formulas estimate the concrete strength from the water-cement ratio only, and they are usually simple but have restricted limits of validity. For improvement, a new type of strength formulas is offered in this paper, formulas that have a second independent variable beside the water-cement ratio, such as the cement content, or water content, or paste content, etc. Such augmentation (a) improves the accuracy of the strength estimation; (b) shows that if two comparable concretes have the same water-cement ratio, the concrete having the higher cement content has the lower strength; and (c) shows that the magnitude of the changes in concrete strength depends on how the water-cement ratio is changed, by changing the cement content or the water content. Experimental data support these expectations. A formula is also presented for the effect of the other kind of porosity, the air content on the concrete strength. The combination of this with any good strength formula gives good fit with experimental results both of air-entrained and nonair-entrained concretes.
Get full access to this article
View all available purchase options and get full access to this article.
Acknowledgments
The writers wish to express their appreciation to Mr. Stephen Chestnut for his help in the production of the electronic version of the figures.
References
Abrams, D. A. (1918). “Design of concrete mixtures.” Bulletin 1, Structural Materials Research Laboratory, Lewis Institute, Chicago.
Graf, O., Albrecht, W., and Schaffler, H. (1960). Die Eigenschaften des Betons, 2nd Ed., Springer, Berlin.
Popovics, S. (1969). “Effect of porosity on the strength of concrete.” J. Mater., 4(2), 356–371.
Popovics, S. (1985). “New formulas for the prediction of the effect of porosity on concrete strength.” ACI J., 82(2), 136–146.
Popovics, S. (1990). “Analysis of the concrete strength versus water-cement ratio relationship.” ACI Mater. J., 87(5), 517–529.
Popovics, S. (1998). Strength and related properties of concrete, Wiley, New York.
Ujhelyi, J. (1988). “Mix design of concrete and prediction of its compressive strength.” Epitoanyag, 6, 207–213 (in Hungarian).
Ujhelyi, J. (1989). “Mix design of concrete and prediction of its compressive strength.” Epitoanyag, 1, 1–9 (in Hungarian).
Walker, S., and Bloem, D. L. (1961). “Effects of aggregate size on properties of concrete.” ACI J., 57, 283–298.
Zielinszki, S. (1909). “The development of setting of Roman and portland cements in pastes, mortars and concretes.” Proc., Int. Assoc. for Testing Materials, Vol. I, 1–55.
Zielinszki, S., and Zhuk, J. (1901). “Comparative investigation of Roman cements.” Proc., Third Int. Congress of the Assoc. for Testing Materials (in Hungarian).
Information & Authors
Information
Published In
Journal of Materials in Civil Engineering
Volume 20 • Issue 7 • July 2008
Pages: 459 - 463
Copyright
© 2008 ASCE.
History
Received: Mar 9, 2006
Accepted: Nov 13, 2006
Published online: Jul 1, 2008
Published in print: Jul 2008
Notes
Note. Associate Editor: Jason Weiss
Authors
Metrics & Citations
Metrics
Citations
Download citation
If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download.