Survey on the State of Deterioration of Highway Bridge Concrete Slabs in a Snowy Region and Countermeasures Based on the Cathodic Protection Method

The replacement of bridge RC slabs has marked the start of expressway renewal work. On the snowy Hokuriku expressway, the deterioration caused by the combination of alkali–silica reaction (ASR) with steel corrosion is accelerated by the application of de-icing salts. Therefore, it is imperative to identify and determine the leading cause of deterioration of each bridge when planning maintenance. In this study, a survey on the amount of chloride penetration into concrete, and the degree of ASR of concrete was investigated using cores taken from RC slabs in a viaduct in the Kanazawa City area. Based on this survey, a new cathodic protection method was applied, and titanium wire sensors monitored its effectiveness. Finally, it was determined that the new cathodic protection method effectively controlled the corrosion of steel bars of reinforced concrete slabs in a saline environment with de-icing salts.