Durability and fatigue of basalt fiber-reinforced polymer bars gripped with steel wedge anchors

This paper presents the test results of a durability study on a novel basalt fiber-reinforced polymer (BFRP) bar-anchor system. The BFRP bars were exposed to saline and alkaline solutions for 10 weeks before being anchored and tested under static and fatigue loading. Unconditioned basalt, glass, and carbon specimens were also tested and served as controls. Regardless of the fiber material, all the bar-anchor systems withstood their ultimate tensile loading with no sign of slippage or premature failure in the anchor zones. Conditioning of the BFRP bars in saline and alkaline solutions resulted in 7 and 9% decreases, respectively, in the systems' tensile capacity. A decrease of 11% in the modulus of the alkali-conditioned BFRP specimens was also observed. The fatigue test results showed that the fatigue life of the bar-anchor system was primarily affected by the applied stress range. In addition, continuous immersion of the BFRP bar in the alkaline solution increased its tendency to fracture prematurely in the anchor zone. The fatigue limit of the BFRP bar-anchor system was determined to be 4% of its ultimate capacity, compared with 3 and 10% for the glass and carbon systems, respectively.