Effects of Construction Time and Coarse Aggregate on Bridge Deck Cracking

Temperature changes in bridge decks have long been identified as a significant early-age cracking contributor within the first few days after placement due to changes in ambient conditions and concrete heat of hydration. Development of a method of quantification of how materials and construction methods can influence bridge deck thermal stress was the goal of this project. A concrete mixture test series was then performed to quantify bridge deck concrete material thermal stress behavior with different coefficients of thermal expansion and placement times. Development of thermal stress equal to 75% of the stress at cracking resulted from concrete placed in the morning with a high thermal expansion coefficient. Thermal stresses were also found to be able to be reduced by up to 50% by placing concrete with a lower thermal expansion coefficient at night.