Documenting the Construction of a Plain Concrete Bridge Deck and an Internally Cured Bridge Deck

摘要

Durable and long lasting concrete is important, especially for bridge decks, which are susceptible to premature cracking and corrosion of the reinforcing steel. To increase the durability of the concrete and its service life, many transportation agencies use high-strength concretes. However, high-strength concretes often have problems with early age cracking due to shrinkage. These cracks can then open a path for chloride ions (found in road salts) to reach the reinforcing steel. The results of this research, which compared bridge installations on two structures in Monroe County, Indiana, confirm that internally cured concrete presents a better alternative to traditional plain concrete for durable bridge decks. With internally cured concrete, a portion of the fine aggregate in the concrete is replaced with the same volume of prewetted lightweight aggregate. As the concrete cures, water from the prewetted aggregate provides the hydration necessary for curing, and also enables curing from the inside. This internal curing process results in a concrete with less initial cracking, less shrinkage, lower thermal stress, lower strain, and greater resistance to chloride ion penetration, with similar or slightly higher strength, relative to plain concrete.