Chloride-induced corrosion of steel fiber near the surface of ultra-high performance concrete and its effect on flexural behavior with various thickness.

• Steel fibers on surfaces of UHPC immersed in chloride solution were corroded after a year. • Flexural strength of thin UHPC panel (10 mm) was decreased by fiber corrosion. • Fiber corrosion on surface led no substantial strength decrease of thick UHPC panel. The results of experimental investigation of ultra-high performance concrete (UHPC) by evaluating the flexural response are presented in order to qualitatively evaluate the effects of chloride-induced corrosion. The third-point bending test is carried out using the hydraulic servo-controlled testing machine. The experimental variables are thickness of specimen (10, 25 and 50 mm), immersion duration, and mixture design of UHPC. The specimens are immersed in 10 wt% NaCl solution up to a year to induce corrosion. The effect of chloride-induced corrosion of steel fiber of UHPC is evaluated in terms of compressive strength, flexural strength and flexural toughness. The experimental results indicate that there is no significant loss in flexural strength and toughness for the specimens which were thicker than 25 mm over a period up to 365 days of immersion in chloride solution; whereas, the specimen with thickness of 10 mm showed about 10% decrease in maximum stress and corresponding toughness after 180 days of the immersion. Furthermore, it is revealed by comparing the compressive strength with and without fibers that the presence of steel fibers in UHPC under corrosive environments do not lead to substantial strength decrease. [ABSTRACT FROM AUTHOR]