EXPERIMENTAL STUDY ON THE MECHANICAL PERFORMANCE OF POST-FIRE CONCRETE CONFINED BY CFRP SHEETS

Compressive tests on post-fire concrete confined by CFRP sheets are carried out. Emphasis was laid on the effect of temperature and number of CFRP layers. According to the measured stress-strain curves, the influence of exposed temperature and number of CFRP layers on concrete mechanical performance such as compressive strength, ultimate strain and initial stiffness is discussed. The test results show that CFRP sheets offer a significant confining effect on the compressive failure modes, and greatly increase the compressive strength of fire damaged concrete. This suggests that CFRP confinement could be an effective method to repair and strengthen concrete structures after fire. Meanwhile, comprehensive analysis on the influence of temperature softening effect and CFRP hardening effect shows that the latter plays a dominant role. Moreover, based on existing models, a simplified model to evaluate the mechanical performance of post-fire concrete confined by CFRP sheets is proposed. Its accuracy and applicability are verified against available test results.