One big problem encountered was that the heat produced by the curing concrete would be so great that would take 125 years to cool and the resulting stresses would have caused the dam to crack and crumble away. This was alleviated by instead of the dam being a single block of concrete; the dam was built as a series of individual columns. Trapezoidal in shape, the columns rose in five-foot lifts. This helped the heat dissipate but to help the concrete properly cool each form also contained cooling coils of 1" thin-walled steel pipe. When the concrete was first poured, river water was circulated through these pipes. Once the concrete had received a first initial cooling, chilled water from a refrigeration plant on the lower cofferdam was circulated through the coils to finish the cooling. As each block was cooled, the pipes of the cooling coils were cut off and pressure grouted at 300 psi by pneumatic grout guns2.
I've seen it hot enough to start to melt rubber-soled shoes.
