Estimating the 95th Percentile of the Paste-Void Spacing Distribution in Hardened Cement Paste Containing Air Entrainment.
Estimating the 95th Percentile of the Paste-Void Spacing
Distribution in Hardened Cement Paste Containing Air
Entrainment.
(812 K)
Snyder, K. A.
RILEM Workshop on Frost Dmage in Concrete (PRO 25).
Proceedings. June 28-30, 1999, Minneapolis, MN, 75-85
pp, 1999.
Keywords:
cements; air entrainment; cement paste; air-void
spacing; air-void system; freeze-thaw; spacing equations
Abstract:
The spacing equations of Powers, Philleo, and Pleau and
Pigeon are used to estimate the uniform thickness of
paste surrounding entrained air voids that is required
to encompass 95% of the air-paste system. Spacing
equation accuracy is determined by comparison to the
numerically exact result of Lu and Torquato. The air
void system is approximated by spheres with radii from a
lognormal distribution. For the systems studied here,
both the Philleo and the Pleau and Pigeon equations are
accurate to within approximately 10%. The Powers spacing
factor can be used to estimate the same quantity to
within a factor of two, and could be made far more
accurate by adjusting the result using the variance in
the air void radius distribution.
Building and Fire Research Laboratory
National Institute of Standards and Technology
Gaithersburg, MD 20899