Comparison between ASTM D7205 and CSA S806 tensile-testing methods for glass-fiber-reinforced-polymer bars

The American Society of the International Association for Testing and Materials (ASTM) D7205 / D7205M-06 and the Canadian Standards Association (CSA) S806 contain the commonly used test methods for characterizing the tensile properties of glass-fiber-reinforced-polymer (GFRP) bars for use as reinforcement in concrete structures. These two standards, however, use different anchor dimensions and loading rates, thereby possibly yielding different properties for the same type of FRP bars. This paper assessed the results of a four-laboratory testing program comparing the sample preparation methods and test results according to ASTM D7205 and CSA S806. Each laboratory tested at least 10 samples prepared according to the recommendations in Annex A of the ASTM standard, and Annex B of CSA S806. Each type of sample was prepared by a single laboratory in order to minimize variation among the test specimens. The results show a statistically significant difference between the tensile strength measured using the CSA and ASTM provisions. Regardless of specimen preparation, the modulus of elasticity of the GFRP bars was the same with both test standards, but the ASTM standard returned a wider variation than the CSA