Bond strength of glass fibre-reinforced polymer ground anchors with helically wound ribs in different bonding agents

Abstract

Bond strength of glass fibre-reinforced polymer (GFRP) bars with helically wound ribs was experimentally investigated in this study and compared to that of smooth glass fibre-reinforced polymer bars and steel bars. A total of 63 pullout specimens are tested. Variables of the tests involved four types of bars, namely, glass fibre-reinforced polymer bar with helically wound ribs, smooth glass fibre-reinforced polymer bar, ribbed steel bar and smooth steel bar, as well as different bonding agents, including normal concrete, high-performance concrete, grout and epoxy resin. Test results showed that bond failure of glass fibre-reinforced polymer bars with helically wound ribs is because of the shearing off of the ribs with small slips, and the ribs helically wound can improve the bond strength of glass fibre-reinforced polymer bars by 3∼14 times, which is around 13, 9·31 and 15·7 MPa in concrete, grout and epoxy resin, respectively. In addition, polypropylene fibres in high-performance concrete can improve the bond behaviour of anchors.

Keywords:

• Ground anchor
• Glass fibre-reinforced polymer bar
• Helically wound rib
• Bonding agent
• Bond strength
• Pullout test

Acknowledgements

The authors gratefully acknowledge the financial support of the National Key Basic Research Program of China (Project No. 2012CB026200), and the Fund of Western Communications Construction Scientific and Technological Project by the Ministry of Communications of the People's Republic of China (No. 200631882244).