A corrosion prediction method for weathering steels

Japanese Specification for Highway Bridges [Japan Road Association: Specification for Highway Bridges-I & II, 2002.3] has been revised in 2002, which clearly states that degradation of bridge members, including those of weathering steels, to occur in prolonged period of time must be taken into account at the design stage to realize long term structural durability. To cope with the revised paradigm, SABI chemistry committee in Japan Society of Corrosion Engineers has proposed durable state concept [SABI Chemistry Committee of Japan Society of Corrosion Engineers, in: Proc. 132nd Symposium for Corrosion and Protection, 2001.6.25, p. 3], which is defined as a condition in which corrosion rate of steel is slow enough not to form thick rust [H. Kihira, K. Shiotani, H. Miyuki, T. Nakayama, M. Takemura, Y. Watanabe, Doboku Gakkai Ronbun-shu (J. Japan Soc. Civil Engineers) No. 745/I-65, 2003.10, pp.77-87]. Since corrosiveness of atmosphere differs by location, a corrosion prediction method for both conventional and advanced weathering steels [H. Kihira, A. Usami, K. Tanabe, M. Ito, G. Shigesato, Y. Tomita, T. Kusunoki, T. Tsuzuki, S. Ito, T. Murata, in: Electrochemical Society Proceedings, vol. 99-26, 2000, pp. 127-136] is needed to ensure structural durability for future. Thus, versatile computational scheme for it has been derived through mathematical modeling based upon the durable state concept.