Consequence of surface preparation techniques on the bond behavior between concrete and CFRP composites

This study investigated the influence of surface preparation techniques on the bond behavior between carbon fiber-reinforced polymer (CFRP) sheet and concrete. For this purpose, one hundred and eight concrete prisms (150 x 150 x 200 mm) were casted with different surface preparation technique (Without surface preparation, smooth surface preparation (leveled, roughened, and brushed with steel wire cup brush), and smooth surface preparation with holes of drilling amplitude (2.5, 5, and 10 mm) and drilling diameter (6, 10, and 14 mm)), CFRP bonded length (50, 75, and 100 mm), CFRP bonded width (50, 75, and 100 mm), and concrete compressive strength (25 and 50 MPa). After that, the specimens were tested under double-shear test then investigated in terms of mode of failure and bond-slip behavior. Experimental results showed that the drilling surface significant impact on the bond behavior in which the bond strength increased with the increase of drilling amplitude and drilling surface. It was also found that ultimate slippage of the tested specimen's increased with the increase of drilling amplitude up drilling amplitude of 2.5 mm and then the ultimate slippage decreased after this limit. Moreover, CFRP bonded length and width had a notable impact on the ultimate bond strength and corresponding slippage. On the other hand, concrete compressive strength had no notable influence on the bond strength with little impact on corresponding slippage. Two types of failure are observed with adhesive failure at the interface between concrete and CFRP sheet) and peeled-off concrete interface with different thickness (tiny, modest, large, and huge) of concrete layer broken off and attached to CFRP sheet after failure. (C) 2019 Elsevier Ltd. All rights reserved.