EXPERIMENTAL INVESTIGATION OF CRACKING BEHAVIOUR OF GFRP-REINFORCED CONCRETE BY PRISM TENSION TESTS

Due to the low modulus of elasticity and high tensile strength of GFRP reinforcing bars and their interaction with the surrounding concrete, the bond performance of GFRP bars differs from that of steel bars. Designs of GFRP reinforced concrete are often governed by deflection and crack control at the serviceability limit state. In order to permit single design equations, bond capacity of GFRP bars are often normalized to that of steel bars using the so-called kb adjustment factor. GFRP bars are manufactured with a variety of surface preparations and conditions affecting bond resulting in quite different values of kb. This study reports a series of prism tension tests in which a single long bar is embedded in a concrete prism and subject to direct tension from which values of kb can be determined. This non-standard test has the advantage of providing quantitative, in addition to qualitative comparison of cracking behaviour as it is affected by reinforcing bar characteristics.Paper 20