EFFECTS OF SEVERE ENVIRONMENTAL EXPOSURE ON COMPRESSIVE BEHAVIOR OF CFRP-CONFINED CONCRETE

Abstract

The objective of this research is to investigate the influences of severe
environment on the behavior and strength of CFRP-confined concrete under
uniaxial compression. Monotonic and cyclic compressive tests were conducted
on Ø20x45 cm cylindrical concrete samples exposed to laboratory-simulated
wet-dry cycles in chloride environment for 6, 13 and 19 months. It has been
found that the compressive strength of CFRP-confined concrete was enhanced
when compared to unconfined concrete. For the CFRP-confined specimens,
compressive strength under monotonic compression increased initially after
being exposed to wet-dry cycles for 6 months, but started to deteriorate after
longer exposure. On the other hand, compressive strength of the CFRP-confined
specimens under cyclic compression increased for all durations of
environmental exposure. The environmental reduction factor (C_E) obtained from
the strains in CFRP at failure in specimens exposed to wet-dry cycles were higher
than the recommended value in the ACI 440-2R Guideline. Therefore, the
recommended values are safe for design of FRP strengthening in both normal
and severe environments. In addition, upon inspection of concrete samples with
steel reinforcement using the half-cell potential method, it has been suggested
that CFRP confinement could help reduce the tendency of steel corrosion in
chloride environment.