BRIDGE DECK PRESERVATION SYSTEMS FOR EXPRESSWAY NETWORKS

摘要

Deicing chemicals such as sodium chloride, NaCl, are typically used in winter season tornprevent the icing of pavements and bridges. However, these deicing chemicals are knownrnto cause severe degradation and deterioration of concrete bridge decks. These chemicalsrnpenetrate into concrete and corrode the reinforcements, and thus exacerbating concreterndamage. To extend the durability of concrete decks, installation of wearing surface overrnthe concrete deck has been implemented around the world. This wearing surface, which isrnplaced on the top of a concrete deck, is required to prevent the infiltration of water andrnaggressive deicing chemicals. Different types of wearing surfaces or overlays have beenrntried by Korea Expressway Corporation. An asphalt concrete overlay along withrnwaterproofing membranes had typically been adopted to protect concrete deck. However,rnthe performance of this system was not satisfactory because severe deterioration of thernoverlays and decks had been reported. Recently, concrete overlays are mainly used forrnnew and existing bridges in KEC. An exposed (or monolithic) concrete deck made of highperformancernconcrete was also proposed for bridges where the use of deicing chemicalsrnis limited. The leakage of deicing chemicals through expansion joints has also caused therndeterioration of bridge decks.