PSI - Issue 28

Jamal A. Abdalla et al. / Procedia Structural Integrity 28 (2020) 1295–1302 Author name / Structural Integrity Procedia 00 (2019) 000–000

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It has been observed that for almost all AA-P specimens the failure takes place in the AA plate adhesive interface due to the weaker bond between the two surfaces compared to the adhesive concrete interface which have relatively higher bond. Conversely, for the AA-R plates the failure load increases with the increase in both concrete strength and bonded length since for almost all AA-P specimens the failure takes place in the adhesive concrete interface due to the weaker bond between the two surfaces compared to the AA-R plate adhesive interface, which have relatively higher bond due to the surface treatment of the AA plate bonded to adhesive. In other words the concrete strength is contributing in resisting the debonding failure mode, given that the failure takes place in the concrete a few millimetres within the concrete surface connected to AA-R plate. 3.3. Failure modes The failure mode for AA-P plates usually takes place in the plate adhesive interface due to the weak bond between the plate plain surface and the adhesive (Fig. 6 (a) and (b)). There are few exceptions for the 20 MPa concrete strength, as in some cases when the bond length is short the stress concentration in the vicinity causes failure in concrete (concrete spalling) due to the low concrete strength of this group. On the other hand, typically due to the strong bond strength between the AA-R treated surface and the adhesive, the failure of AA-R samples takes place in the concrete adhesive interface accompanied with concrete spalling in some cases due to the high roughness of the AA-R plate bonded surface, which results in concentration of stresses in the vicinity of the loaded end (Fig. 6 (c) and (d)).

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(b)

(d)

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Fig. 6. Failure modes of prisms (a) plain surface 60MPa; (b) rough surface 60MPa; (c) plain surface 20MPa; (d) rough surface 20MPa

4. Conclusions This study investigated the utilization of AA plates as a strengthening material. It showed promising outcomes when the AA plate surface is roughened. It can be concluded from this study that: