PSI - Issue 64

Sareh Akbarpoor et al. / Procedia Structural Integrity 64 (2024) 822–832 Sareh Akbarpoor/ Structural Integrity Procedia 00 (2019) 000 – 000

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For EA-100 specimens, sand treatment was not applied to the CFRP laminates. The adhesive filled the groove within the bonded length area. Using spacers, the CFRP laminate was inserted into the centre of the groove to ensure even adhesive distribution. Finally, the groove was filled, and the surface levelled with the adhesive. After 7 days of curing, the specimens were prepared for pull-out testing. 2.3. Test Setup The bond behaviour of prepared specimens was evaluated using a single-lap shear test setup, as depicted in Fig. 3. Loading was applied at a controlled displacement rate of 1 mm/min. In addition, a Linear Variable Differential Transformer (LVDT) was installed on loaded end of CFRP laminate in bonded length area. It should be noted that before performing the tests, all specimens were painted.

Fig. 3. Pull-out test setup.

3. Results and discussion In this section the bond-slip behaviour and failure modes of pull-out specimens using two different adhesives will be compared. 3.1. Bond-slip behaviour As depicted in Fig. 4 and 5, specimens using the developed cement-based adhesive exhibit notably ductile bond behaviour in comparison to those using epoxy adhesive. The post-peak behaviour of CBA-S-100 specimens showed a gradual decrease in sustained load during the test, confirming the ductile nature of this strengthening system in practical applications. This can be attributed to the mix of this developed adhesive which consists of primer. Regarding the maximum bond stress, it is evident that the NSM FRP system employing the developed cement based adhesive achieved approximately 65% of the value observed for the NSM FRP system utilising epoxy adhesives. This highlights the potential of the developed cement-based adhesive as a viable alternative, particularly in scenarios where performance under elevated temperatures and moisture is critical.