Effect of Cracking on Chloride Content in Concrete Bridge Decks

Abstract

Field surveys to measure bridge deck cracking and chloride contents of uncracked as well as cracked concrete were performed as a part of a larger research program evaluating bridge deck performance. Three deck types were studied: monolithic decks, decks with a conventional high density concrete overlay, and decks with a high density concrete overlay containing either a 5 or 7% replacement of cement by silica fume. The results of the field surveys indicate that bridge deck type does not have a major effect on chloride content. For samples taken away from cracks, the average chloride concentration at the top of transverse reinforcement rarely exceeded even the most conservative estimates of the corrosion threshold for conventional reinforcement. Chloride concentrations taken at crack locations, however, often exceeded the corrosion threshold of conventional reinforcement in less than 1 year.