Vm. Karbhari et M. Engineer, EFFECT OF ENVIRONMENTAL EXPOSURE ON THE EXTERNAL STRENGTHENING OF CONCRETE WITH COMPOSITES - SHORT-TERM BOND DURABILITY, Journal of reinforced plastics and composites, 15(12), 1996, pp. 1194-1216
The pressing need for rehabilitation and retrofit strategies that enco
mpasses new and emerging materials and technologies, results from the
need to simultaneously repair existing structures while attempting to
increase both their performance levels and life spans. A large number
of techniques currently exist for strengthening highway bridges rangin
g from the use of external post-tensioning to the addition of epoxy bo
nded steel plates to the tension surface. The use of composite plates
for the purpose of external reinforcement has considerable potential.
However, there is a critical need to investigate the degradation of th
e composite-concrete interface after exposure to environmental conditi
ons that include moisture, sea water, freezing and freeze-thaw. In thi
s investigation, the effect of five different environmental conditions
on the performance of plated beams is considered from aspects related
to materials and durability. It is shown that the selection of the ap
propriate resin system is critical to success, and the dangers of sele
cting systems with low glass transition temperatures and drastic drops
in instantaneous modulus as a function of temperature are discussed.
Two different resin systems are compared using the same fibrous reinfo
rcement and an overall view of durability at the concrete-composite in
terface is elucidated.