Acoustic Emission Performances of Stressed-GFRP Bars Embedded in Concrete under Accelerated Aging Conditions

摘要

This research presents test results of an experimental study to investigate tensile strength degradation of stressed-GFRP bars embedded in concrete after accelerated aging. The experimental program included twelve tensile specimens with two different types of GFRP bars [Wrapped surface (herein, Type-A) and Sand-coated surface (herein, Type-B)]. Specimens were placed in a weathering chamber [46°C (115℉) and RH: 80%] with a sustained load. In addition, acoustic emission as a nondestructive evaluation was performed to investigate the degradation of GFRP bars. Results revealed that the residual tensile strengths were about 85.5 and 82.5% (reduction by 14.5 and 17.5%) after 300 days of exposure, respectively, for Type-A and Type-B bars. This paper devotes attention to the acoustic emission performance on the aged GFRP tensile curves. Test results indicated that changes in AE parameters due to aging could be identified as strength/stiffness degradation. AE parameters also showed a good correlation with the mechanical responses of test specimens after accelerated aging.