| The long-term durability of concrete can be compromised by excessive concrete temperatures or temperature gradients and lack of moisture during the first few days after placement. Because the concrete binder components undergo temperature-dependent hydration reactions during this period, atmospheric and construction conditions influence the ultimate concrete quality. To understand this interaction, curing concrete bridge energy balances were estimated with meteorological techniques and calorimetry and model experiments were performed. The agreement of concrete hydration heat estimates from the energy balances, calorimetry experiments, and model simulations validates our methodology and results.; In Chapter 2, we estimate from meteorological measurements and techniques the energy balances of four curing concrete bridge decks. One challenge is to determine fluxes from small surfaces (largest horizontal dimension <50 m) in a heterogeneous landscape with methods that are best suited for larger, more homogeneous areas. Estimating the concrete heat generation provides the means to successfully meet this challenge. The energy balance and calorimetry estimates of 24 h concrete heat generation agree within 20%. Between 70–85% of the concrete's heat transfer occurs at its top surface and heat transfer through steel support beams can be significant. A new parameterization for computing bulk exchange coefficients for small areas is developed.; Chapter 3, we improve with calorimetry experiments a simple bimolecular heat generation expression for hydrating binder. We show that this expression, with a new parameterization accounting for retarder effects on hydration rates, simulates temperatures to within 2°C and 72 h heat generation (∼265 kJ kg−1) to within 10% of the observed.; In Chapter 4, we present models developed with the field and laboratory work and show that the highest concrete temperatures occur at high initial concrete temperatures and air temperatures and humidities, and at low wind speeds and cloud cover fractions. Peak bridge concrete temperatures can exceed 60°C. Large concrete temperature gradients (∼2°C cm−1 ) occur at the concrete top surface and the support beam top. An application of the 1D model with input from a weather forecast model predicts concrete temperatures within 2°C of the observed and so is a suitable operational model. |
