Relation between Tensile Strength and Modulus of Rupture for GFRP Reinforcing Bars

This paper presents an investigation correlating tensile properties of glass fiber-reinforced polymer (GFRP) bars with the results obtained from flexural testing. Composite bars, in contrast to conventional steel, when used in structures exposed to aggressive environments can significantly increase the durability and lifetime. However, the use of GFRP bars in concrete structures is still limited due to the variability of mechanical properties and bar quality among different manufacturers. Rational and fast testing methods for these reinforcing bars are needed. A flexure test is relatively easy and potentially could be used to determine the tensile strength of bars, which is a primary mechanical property that must be determined. This research investigates a possible correlation between the tensile strength and the modulus of rupture of GFRP bars. A Weibull weakest link model is employed. The effect of bimodularity of GFRP material in tension and compression also is investigated.