Residual capacity of fiber-reinforced concrete elements exposed to chloride-rich environment

Research works regarding the behavior of Fiber-Reinforced Concrete (FRC) have helped to understand the positive effects of fibers. Nowadays, it is well-known that the use of fibers enhances the mechanical behavior of Reinforced Concrete (RC) structures at Serviceability Limit State (SLS) and Ultimate Limit State (ULS). Fibers in RC elements may improve the cracking pattern, leading to narrower and more closely spaced cracks. However, even though many research works have been carried out, FRC durabil-ity performance in corrosive environments is still not well-understood. In this context, the present article describes a second phase of a large experimental campaign carried out at the University of Brescia, Italy. This test procedure was specifically developed to evaluate the chloride-induced corrosion in both RC and FRC elements. Several specimens reinforced by a rebar of 12 mm in diameter were cast employing four different mixtures: (1) plain concrete, (2) steel fiber-reinforced concrete, and (3) polypropylene fiber-reinforced concrete. Then, they were submitted to wet-dry cycles in a water solution containing 50 g/L of NaCl for 2 years. Specimens were subjected to a constant tensile stress of 300 MPa, the tensile stress of an RC structure at SLS. After the first phase in which it was demonstrated by means of a natural corrosion process that the test procedure adopted was adequate to evaluate the corrosion induced by chlorides in RC and FRC elements, this second phase provides a new contribution to the behavior of FRC after long-term exposure to chlorides.