AN INTEGRATED ACOUSTO-MECHANICAL ENERGY APPROACH FOR MONITORING FLEXURAL BOND-SLIP BEHAVIOUR OF GFRP BARS AND CONCRETE

Abstract

Mechanical testing data and acoustic emission (AE) data can be independently analysed to evaluate the bond deterioration process of glass fibre reinforced polymer (GFRP) rebars and concrete. However, one type of data may not be adequate for thorough and accurate damage characterization and assessment. Sentry function, a unitless quantity, which relates mechanical and AE energy, has been efficiently applied in polymer composites and multi-layered laminates to study damage progression, including delamination. The sentry function has not been used in any of the past studies to understand the bond-slip behaviour of reinforcements in concrete. The present study attempts to exploit the effectiveness of the sentry function to evaluate the flexural bondslip behaviour of GFRP rebar and concrete. A thorough AE monitoring experimental programme has been conducted to evaluate and understand the interfacial bond deterioration process between GFRP reinforcement and concrete under flexural loading. The experimental test variables include confinement conditions and embedment length of the GFRP bar. Findings from the study suggest that the sentry function proves to be a successful and effective tool for evaluating the GFRP-concrete flexural bond deterioration. The sentry function captures and delineates the development and utilization of various bond stress transfer mechanisms (chemical adhesion, mechanical interlocking, and frictional resistance) involved in bond-slip behaviour.