Sorption and Diffusion of Water, Salt Water, and Concrete Pore Solution in Composite Matrices.
Sorption and Diffusion of Water, Salt Water, and
Concrete Pore Solution in Composite Matrices.
(940 K)
Chin, J. W.; Nguyen, T.; Aouadi, K.
Journal of Applied Polymer Science, Vol. 1, 483-492,
1999.
Keywords:
composite materials; sorption; diffusion; water; salt
water; concretes; polyesters
Abstract:
ln recent years, the use of fiber-reinforced polymer
composites in civil infrastructure has been promoted as
a solution to the deterioration of bridges, buildings,
and other structures composed of traditional materials,
such as steel, concrete, and wood. Any application of a
polymer composite in an outdoor environment invariably
involves exposure to moisture. There is also potential
for exposure to saline conditions in waterfront or
offshore structures, and alkaline environments, as would
be encountered by a reinforcing bar in a cementitious
material. This study characterizes the sorption and
transport of distilled water, salt solution, and a
simulated concrete pore solution in free films of vinyl
ester, isophthalic polyester (isopolyester) and epoxy
resins, all commercially important materials for use in
structural composites. Diffusion of all three liquids in
each of the three materials was observed to follow a
Fickian process. Mass loss was observed for the
isopolyester in salt water andconcrete pore solution at
6O deg C, suggesting hydrolysis that was accelerated by
the high temperature exposure. Both the rate of uptake,
as well as the equilibrium uptake, were greater at 6O
deg C, compared with ambient conditions. Diffusion
coefficients calculated from the mass uptake data
revealed that, although the epoxy resin had the highest
equilibrium uptake, it had the lowest diffusion
coefficient.
Building and Fire Research Laboratory
National Institute of Standards and Technology
Gaithersburg, MD 20899