Impact-resistant behavior of steel-fiber-reinforced porosity-free concrete beam

Abstract

Porosity-free concrete (PFC) is a newly developed ultra-high-strength concrete with a compressive strength of 400 MPa. PFC reduces the weight of bridge superstructures, protects against collisions with flying objects, increases seismic-resistant capacity, and improves long-term durability. At present, basic material properties of PFC, such as compressive strength, tensile strength, and tensile toughness have been revealed. However, impact resistance has not been examined. In this study, in order to investigate the impact-resistant behavior of steel-fiber-reinforced PFC, falling-weight impact-loading tests were conducted on a PFC beam, considering the mixing ratio of steel fiber and the height of falling-weight as variables. To investigate the effects of compressive strength on the impact-resistant behavior of the concrete beam, tests using high-strength concrete (HC) with a compressive strength of 100 MPa were also conducted as general high-strength concrete. From this experimental study, the following results were obtained: 1) impact resistance capacity of the PFC beam can be more drastically improved by mixing 2 vol.% of steel fiber compared to the HC beam; 2) bonding resistance between PFC and steel fiber could play an important role in upgrading the impact resistance. PFC mixed with 2 vol.% steel fiber could be used as an effective reinforcement material for impact protection structures.