AUTHOR=Zhang Lifei , Zheng Yu , Hu Shaowei , Yang Jiasheng , Xia Lipeng TITLE=Identification of Bond-Slip Behavior of GFRP-ECC Using Smart Aggregate Transducers JOURNAL=Frontiers in Materials VOLUME=7 YEAR=2020 URL=https://www.frontiersin.org/journals/materials/articles/10.3389/fmats.2020.00165 DOI=10.3389/fmats.2020.00165 ISSN=2296-8016 ABSTRACT=

The behavior of the bond between Engineering Cementitious Composites (ECC) and Glass Fiber Reinforced Polymer (GFRP) bar has a strong effect on the behavior of this composite structure. However, it is difficult to detect the failure mode and damage status of the interface using traditional testing methods. This is due to the strain-hardening mechanical behavior of ECC. An effective monitoring method using patch lead zirconate titanate (PZT) transducers and active sensing technology was used to detect the internal damage. In this active sensing technology, a PZT smart aggregate was bonded onto the middle surface of ECC, acting as a sensor. This study conducted a series of experimental studies on the bond behavior of GFRP-reinforced ECC based on pull-out tests. The test results are presented and discussed to investigate the bond-slip relationship and failure mechanism between FRP reinforcing bars and the ECC matrix. The status of interfacial damage between ECC and GFRP can be represented by the attenuation change of the stress wave. Finally, a damage index (DI) obtained using wavelet packet analysis is proposed to evaluate and quantify the level of FRP–ECC interaction damage. The analytical results reveal that the debonding and failure mechanism can be detected by using this DI index value, and the influence of the diameter of reinforcing bars should be considered, as should the Poisson's effect.