Behavior of High-Nickel Type Weathering Steel Bars in Simulated Pore Solution and Mortar under Chloride-Containing Environment

抄録

Weathering steel (WS) is known to develop higher corrosion resistance than ordinary steel under atmospheric condition due to the formation of a protective, dense rust layer. This aspect, however, has not been studied so far in cement-based materials, which are characterized by high alkalinity and limited oxygen. To address the need for durable RC structure in extreme environments, it is necessary to study the behavior of WS in concrete. Here, a basic investigation was conducted to compare the short-term behavior of a newly developed WS with 1% Ni (NT) to conventional WS with 1% Cr (CT) and carbon steel (PC). One set of steel bars was exposed to solutions with varying air and pH to simulate concrete condition under chloride-containing environment. Another set was embedded in mortar under wet-dry cycle. Corrosion degree based on mass loss, coupled with half-cell potential, and corroded area was obtained. Results indicate that alkalinity or low oxygen appreciably reduces the corrosion rate of steels regardless of composition. These conditions make the corrosion behavior of NT comparable with other conventional steels. It is recommended to explore using longer time and wider cracks in future studies to achieve clearer difference between the steels.