Hoover Dam Bypass Project, Colorado River, USA

For the cast-in-place reinforced concrete foundations and ribs of the arch, a High Performance Concrete mix design was specified that had to achieve a compressive strength of 69 MPas (10’000 psi), together with strict limits on shrinkage and long term creep. This had to be developed and then adapted to provide consistent performance in the extreme temperature conditions, which can vary from below -20°C in winter, to higher than +40° C in summer.