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Hidden Meaning of Water-Cement Ratio.

pdf icon Hidden Meaning of Water-Cement Ratio. (442 K)
Bentz, D. P.; Aitcin, P. C.

Concrete International, Vol. 30, No. 5, 51-54, May 2008.


water; cements; stress (mechanics); volume fraction; particle size distribution; cement paste


Concrete is always characterized by the mass ratio of water to cement (w/c) in the mixture. Unfortunately, for most students and many engineers, the w/c is an abstract number without any particular meaning. Furthermore, this number is inversely related to concrete strength: the lower w/c, the greater the strength.l People generally understand and can remember direct relationships better than inverse relationships. In fact, w/c has a hidden meaning: it's directly linked to the spacing between cement particles in the cement paste. The smaller this spacing, the faster the cement hydrates fill in the gaps between cement particles, the stronger the links created by these hydrates, and most importantly, the stronger the concrete. Additionally, the smaller this spacing, the smaller the sizes of the pores created by seIf-desiccation and the larger the stresses generating autogenous shrinkage.