Bond and durability investigation of basalt fiber and PEN fiber reinforced composites for concrete applications

Abstract

: Bond and durability characteristics of basalt fiber reinforced polymer (BFRP) and polyethylene naphthalate (PEN) fiber/PEN FRP were investigated. Magnitude and distribution of the bond stress between BFRP/PEN FRP and concrete were investigated by double lap shear test. Four different types of durability test were performed: (1) Beam bond test following accelerated conditioning protocols by ACI 440.9R using plain concrete beams strengthened with BFRP or PEN FRP; (2) tensile test of PEN fiber/PEN FRP after immersion in 1N NaOH, 3% NaCl solutions, and water up to 6 months; (3) tensile test of PEN fiber/PEN FRP after immersion in 5% and 10% diluted solutions of HCl; and (4) exposure to natural outdoor environment. Bond test results indicated high bond stress developing over relatively short distance for BFRP that has high elastic modulus (E_BF = 68.4 GPa) while relatively low bond stress developing over longer length for PEN FRP that has low elastic modulus (E_PEN = 17.4 GPa). In the beam bond test, very good behavior was shown by PEN FRP after 4 month’s exposure to wet and alkaline conditions while moderate behavior was shown by BFRP. Overall, the performance of PEN fiber/FRP was satisfactory in all durability tests conducted in this study.