Expansion joints in bridges are usually constructed using either armor & strip seals or preformed joint seals (inset picture, below). The sealant is typically set below the pavement surface by 1/4" or so to keep snow plows & vehicle wheels from coming into contact with them and tearing them out. You don't want to set the joint filler too low since it will collect debris that will eventually get too thick to self-cleans itself during rainfall. Hope this helps answer the question: Cheers!!!
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