- Author
-
Castro, P. F.
|
Carino, N. J.
- Title
- Tensile and Nondestructive Testing of FRP Bars.
- Coporate
- Universidade Federal Fluminense, Rio de Janeiro, Brazil
National Institute of Standards and Technology, Gaithersburg, MD
- Journal
-
Journal of Composites for Construction,
Vol. 2,
No. 1,
17-27,
February 1998
- Keywords
-
building technology
|
fiber reinforced plastic
|
modulus of elasticity
|
nondestructive testing
|
reinforcing bars
|
reasonant frequency
|
statistical methods
|
tensile test
|
ultrasonic pulse velocity
- Abstract
- An exploratory study was carried out to support the development of standard test methods for fiber reinforced plastic (FRP) bars for use as concrete reinforcement. The principal objectives were to develop a simple, economical, and effective system to permit tensile loading of the bars in a universal test machine; to evaluate the influence of the free-length-to-bar-diameter ratio on the measured tensile strength; and to explore the potential of measuring the elastic modulus using available nondestructive test methods. A successful system for applying tensile load was developed. The ends of a bar were embedded in steel tubes using a high-strength gypsum cement mortar. The bars were loaded by gripping the tubes in the conventional wedge friction grips of a tensile testing machine. No statistically significant influence of the free-length-to-diameter ratio was observed for ratios varying between 40 and 70. However, large within-test variability of tensile strength was observed. Dynamic modulus of elasticity was determined using two stress-wave propagation methods: ultrasonic pulse velocity and resonant frequency. The dynamic values compared favorably with static values obtained from tensile stress-strain curves. Recommendations are provided for additional studies to support the development of standard test methods.