Temperature Prediction for High Early Strength Concrete Pavement Repair

High early strength concrete (HESC) materials are frequently used for concrete pavement repair since the rapid strength gain permits reopening to traffic in as little as a few hours. Anecdotally, these materials and repairs have often demonstrated durability worse than the adjacent pavement slabs. The rapid strength gain of HESC is associated with strongly exothermic cement hydration that may lead to high repair slab temperatures and or temperature gradients. To explore these phenomena, several candidate HESC mixtures were prepared and tested with semi-adiabatic calorimetry to characterize the time evolving thermal characteristics. These data were used to calibrate several finite element-based heat transfer models which in turn predict the maximum repair slab temperature and temperature gradient. Predicted slab temperatures as high as 138 degrees C and thermal gradients ranging from 63 degrees C/m to 253 degrees C/m were observed. These findings will help to guide experimental validation of the phenomena.