Subsidence Cracking of Concrete Over Steel Reinforcement Bar in Bridge Decks

Abstract

It is known that subsidence cracking may cause premature deterioration of concrete slab structures in salt laden environments. Chlorides from either deicing salts or marine environments may cause chloride-induced corrosion of the reinforcing steel resulting in spalling of the cover concrete. Concrete specimens with 16 mm (# 5) diameter bars were cast with various cover depths, bar spacing and two concrete mixture types to determine the influence that epoxy coated reinforcement, cement type and bar spacing may have on the probability of subsidence cracking in bridge deck slabs. It was determined that there is not a significant difference in the probability of cracking of concrete between concrete cast with epoxy coated reinforcing steel and bare reinforcing steel. Concrete subsidence cracking was found to be dependent upon the clear cover depth and cement type.