Analytical Formulas for Interfacial Transition Zone Properties.
Analytical Formulas for Interfacial Transition Zone
Properties.
(1023 K)
Garboczi, E. J.; Bentz, D. P.
Advanced Cement Based Materials, Vol. 6, 99-108, 1997.
Keywords:
concretes; cements; conductivity; shrinkage; diffusivity
Abstract:
Two analytical results are presented that are of use to
concrete material technologists. Using a model of
concrete in which the aggregates are spherical, but with
an arbitrary size distribution, a result from
statistical geometry can be used to accureately give the
total interfacial transition zone (ITZ) volume for any
width ITZ and any volume fraction of aggregates. In
reality, the ITZ contains a gradient of porosity and
therefore a gradient of properties. When only a small
volume fraction of aggregates is present (called the
dilute limit), it is possible to analytically solve for
the effect of the ITZ on the overall concrete
properties. This calculation can be carried out for the
effective linear elastic moduli, linear electrical
conductivity/ionic diffusivity, and linear
thermal/moisture shrinkage/expansion. The details of
the calculation are summarized and applications
described.
Building and Fire Research Laboratory
National Institute of Standards and Technology
Gaithersburg, MD 20899