Deterioration Mechanisms of RC Deck Slab Caused by Combined Deterioration from Salt Damage and Alkali-Silica Reaction Due to the Anti-freezing Agents

In regions characterized by cold and snowy climates, the combined deterioration mechanisms resulting from the salt-induced steel corrosion and the expansion alkali-silica reaction (ASR) has emerged notably due to the influence of anti-freezing agents spread out on the road. Consequently, it becomes imperative to precisely diagnose and prognosis the occurrence of these phenomena and incorporate them into the comprehensive maintenance and management plan for the entire bridge structure. This investigation was undertaken to assess the extent of chloride penetration into concrete and the expansivity of concrete due to ASR in RC deck slabs along the Hokuriku Expressway to elucidate the impact of this compounded deterioration on the extracted RC deck slab. The findings revealed that in a significant proportion of RC slab decks where the erosion had transpired, steel corrosion manifested after the infiltration of chloride ions from the anti-freezing agent into the concrete. Furthermore, the formation of cracks, as a consequence of the combined deterioration mechanisms of steel corrosion and ASR, was observed to diminish the physical integrity of the concrete in RC deck slab.