Computer Modeling of the Replacement of "Coarse" Cement Particles by Inert Fillers in Low W/C Ratio Concretes: Hydration and Strength.
Computer Modeling of the Replacement of "Coarse" Cement
Particles by Inert Fillers in Low W/C Ratio Concretes:
Hydration and Strength.
Bentz, D. P.; Conway, J. T.
Cement and Concrete Research, Vol. 31, No. 3, 503-506,
cements; computer models; concretes; blended cements;
compressive strength; hydration; particle size
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.