Freedom Tower, One World Trade Center – New York CityBuilt with the highest strength concrete ever poured in New York City
- Timeline: 2006 - 2012
- Cost: $2 billion
- Size: 1776 feet high; 82 stories
- Concrete used: 240,000 yards
14,000 psi concrete is being used in the first office building to be built on the site of the World Trade Center. It is one of the project's several high-strength mixes, engineered by the iCrete System and produced by Quadrozzi. For quality and consistency, Quadrozzi installed process control systems in its two plants producing the mixes.
iCrete technology uses less cement than typical mixes, and optimizes recycled material content. The 14000 psi concrete used in the Freedom Tower uses up to 40% less cement than conventional concrete. The mix is more cost-effective and contributes to the building's environmental sustainability and safety, which exceed current standards.
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Trump International Hotel & Tower - ChicagoThe tallest structurally reinforced concrete building in the U.S.
- Timeline: 2005 - 2008
- Cost: $750 million
- Size: 1134 feet high; 92 stories
- Concrete used: 180,000 yards, including 14,000 yards of high-strength self-consolidating concrete (SCC)
The Trump International Hotel and Tower's complex design pushes the capabilities of high-strength concrete, according to design firm Skidmore, Owings & Merrill.
At Prairie Materials, the producer supplying the concrete, technical service people tested and prepared unique mix designs for six months, some of which had never been used before. These included:
- 10,000 psi compressive strength for 10-foot-diameter caissons,
- 10,000 psi, low-heat SCC for the 10-foot-thick, 4700-yard mat slab; the largest SCC placement in the U.S.,
- 12,000-16,000 psi SCC for transition floors.
The producer was challenged to produce consistent, high-strength, high-modulus mixes and slump spreads that allowed the SCC to move about 50 feet from the point of placement.
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