Experimental Study on Friction Factor for Fiber Reinforced Polymer Tendons in Pretensioned Prestressed Concrete Members

In this paper, an experimental study on the frictional coefficient of fiber reinforced polymer (FRP) tendons is made and reported. Test on FRP tendons fixed in cement mortar and confined with highly expansive material (HEM), and placed all together inside a steel sleeve pull-out test were conducted. Tests were carried out at various levels of confining pressure. The initial bond and the frictional coefficient of FRP tendons are determined from the graphs of confining pressure plotted against the slippage. The initial bond and the friction coefficient are presented for the FRP tendon with the surrounding HEM. A newly developed pressure transducer was placed in the same manner as the FRP tendon to monitor the confining pressure due to the HEM. The previous results are compared with the present one on Carbon FRP and found to agree well. Also the initial slippage and average bond stress and friction coefficient of Vinylon and Carbon FRP are reported using this monitoring system. The Vinylon FRP is tested for the first time and the large size Carbon FRP are also introduced as they are prime candidates for use in practice.