Corrosion behavior and flexural performance of reinforced SFRC beams under sustained loading and chloride attack

Abstract

The durability of steel fiber reinforced concrete (SFRC) members is of great concern for their application in chloride environments. This paper presents an experimental study of the corrosion behavior of reinforced SFRC (RSFRC) beams subjected to sustained loading and chloride attack, and then of the flexural behavior of these corroded RSFRC beams in four-point bending tests. A two-stage corrosion test was conducted, first with cyclic wetting-drying chloride corrosion and then with accelerated corrosion using external current to produce different corrosion levels. The results indicated that sustained load accelerated rebar corrosion characterized by rapid decrease in corrosion potential, but that loading had a different effect on total rebar mass loss and local corrosion. Meanwhile, at sustained loads within 50% of yielding load, steel fibers bridging the initial flexural cracks showed slight corrosion damage, especially at corrosion ratios lower than 14%. The flexural failure mode may transform from SFRC crushing to steel bar rupture. Increasing sustained load levels resulted in larger reductions in load-bearing capacity for corroded beams at similar corrosion ratios, which indicates an apparent coupling effect of sustained load and chloride corrosion. In contrast, ductility suffered no decline, but rather a slight enhancement due to simultaneously reduced deflection at yielding and ultimate loads.