Controlling early-age temperature variations in concrete bridge decks

The early-age cracking of concrete bridge decks continues to be a major concern, particularly when the concrete mixture design is based on high cementitious materials content or when deck casting/curing is done in unfavorable conditions. Temperature differences between the freshly cast deck and the supporting girders are one potential contributor to early-age cracking. Such cracking can strongly affect the durability of the bridge deck and therefore the maintenance schedule and life-cycle cost of the bridge. This paper presents numerical modeling of temperature development in freshly cast bridge decks, as it depends on heat of hydration and environmental factors. Model validation is accomplished through comparisons with temperatures measured within instrumented bridge decks. The validated models are used for parametric study that examines the effects of cementitious materials content, time of casting, mixture temperature at the time of casting, and degree of solar heating during the first several days after casting. The results demonstrate the potential for evaluating the likelihood of early-age cracking by computationally linking relevant aspects of materials design, structural design, and methods of processing.