High-rate tensile behavior of steel fiber-reinforced concrete for nuclear power plants

• The final goal is to develop a fiber reinforced concrete for containment buildings.
• High rate tensile behavior of FRC was investigated.
• Strain energy frame impact machine was used for tensile impact tests.
• Different rate sensitivity of FRC was found according to the type fiber.
• Adding more fibers by increasing S/a is positive for higher impact resistance of FRC.

The direct tensile behavior of fiber-reinforced concrete (FRC) at high strain rates were investigated for their potential to enhance the resistance of the containment building of nuclear power plants (NPPs) against aircraft impact. Two types of deformed steel, hooked (H) and twisted (T) fibers were employed. To improve the tensile resistance of FRCs even at higher rates by adding more fibers, the mixture of concrete was modified by either increasing the sand-to-coarse aggregate ratio or decreasing the maximum size of coarse aggregate. All FRC specimens produced two to six times greater tensile strength and one to five times higher toughness at high strain rates (4–53 s−1) than those at a static rate (0.000167 s−1). T-fiber generally produced higher tensile strength and toughness than H-fiber at both static and high rates. Although both fibers showed favorable rate sensitivity, T-fiber produced much greater enhancement, at higher strain rates, in tensile strength and slightly lower enhancement in toughness than H-fiber. As the maximum size of coarse aggregate decreased from 19 to 5 mm, the tensile strength and toughness of FRCs with T-fibers noticeably increased at both static and high strain rates.