Fatigue Crack Propagation Behavior of RC Beams Strengthened with CFRP under High Temperature and High Humidity Environment

Abstract

Numerical and experimental methods were applied to investigate fatigue crack propagation behavior of reinforced concrete (RC) beams strengthened with a new type carbon fiber reinforced polymer (CFRP) named as carbon fiber laminate (CFL) subjected to hot-wet environment. <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M1"><mml:mrow><mml:mi>J</mml:mi></mml:mrow></mml:math>-integral of a central crack in the strengthened beam under three-point bending load was calculated by ABAQUS. In finite element model, simulation of CFL-concrete interface was based on the bilinear cohesive zone model under hot-wet environment and indoor atmosphere. And, then, fatigue crack propagation tests were carried out under high temperature and high humidity (50°C, 95% R · H) environment pretreatment and indoor atmosphere (23°C, 78% R · H) to obtain <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M2"><mml:mi>a</mml:mi><mml:mtext>-</mml:mtext><mml:mi>N</mml:mi></mml:math> curves and crack propagation rate, <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M3"><mml:mi>d</mml:mi><mml:mi>a</mml:mi><mml:mo>/</mml:mo><mml:mi>d</mml:mi><mml:mi>N</mml:mi></mml:math>, of the strengthened beams. Paris-Erdogan formula was developed based on the numerical analysis and environmental fatigue tests.