- Author
-
Bentz, D. P.
|
Conway, J. T.
- Title
- Computer Modeling of the Replacement of "Coarse" Cement Particles by Inert Fillers in Low W/C Ratio Concretes: Hydration and Strength.
- Coporate
- National Institute of Standards and Technology, Gaithersburg, MD
Holnam, Inc., Dundee, MI
- Journal
-
Cement and Concrete Research,
Vol. 31,
No. 3,
503-506,
2001
- Keywords
-
cements
|
computer models
|
concretes
|
blended cements
|
compressive strength
|
hydration
|
particle size distribution
- Abstract
- In concretes with water-to-cement (w/c) ratios below about 0.38, a portion of the cement particles will always remain unhydrated due to space limitations within the material. Thus, in many of the high-performance concretes currently being produced, cement clinker is in effect being wasted. This communication examines the possibility of replacing the coarser fraction of a cement powder by an inert filler, to conserve cement without sacrificing material performance. Using the NIST CEMHYD3D cement hydration model, it is demonstrated that for "initial" w/c ratios of 0.25 and 0.30, a portion of the coarser cement particles can be replaced by inert fillers with little projected loss in compressive strength development. Of course, the optimal replacement fraction depends on the initial w/c ratio, suggesting that blended cements need to be produced with the end concrete mixture proportions in mind. This further implies that a cement/inert mixture of specific proportions will only perform optimally in a limited range of concrete mixture proportions.