Argument for Using Coarse Cements in High-Performance Concretes.
Argument for Using Coarse Cements in High-Performance
Concretes.
(380 K)
Bentz, D. P.; Haecker, C. J.
Cement and Concrete Research, Vol. 29, 615-618, 1999.
Keywords:
concretes; hydration; particle size distribution
Abstract:
The NIST cement hydration microstructural model and
experimental studies are used to investigate the effects
of particle size distribution and water-to-cement ratio
on hydration kinetics. Cement hydration is limited by
the availability of water at the cement particle
surfaces. Because a reaction layer forms around each
cement particle during hydration, this availability is
controlled by two factors: the overall water-to-cement
ratio and the particle size distribution of the cement.
As the water-to-cement ratio is decreased, the effects
of particle size distribution on ultimate degree of
hydration become less significant. Thus, in the new
generation, high-performance concretes, more coarsely
ground cements may provide good performance, resulting
in substantial energy savings due to a reduction in
grinding time. This implies that cement fineness should
be optimized based on the mixture proportions of the
concrete in which it will be used.
Building and Fire Research Laboratory
National Institute of Standards and Technology
Gaithersburg, MD 20899