One of the problems concrete contractors were faced with in a pour the magnitude of the Freedom Tower at the World Trade Center was controlling the heat generated in the core of the concrete, along with the changes in temperature, which, during hydration and consolidation, can cause cracks due to stress. The answer to this dilemma within New York's most important structure came from an unlikely source, a California company called iCrete(R).
Based in Beverly Hills, iCrete developed their innovative iCrete System(R), offering record strength concrete and dramatic environmental benefits. The primary supplier of concrete for the Freedom Tower, Quadrozzi Concrete, chose the iCrete brand of concrete to use with supplementary cementitious materials such as fly ash to come up with a high compression, high performance concrete mix. The iCrete System actually optimizes the void space between aggregates, reducing the amount of cement paste required to bond the aggregates. It means less finishing time, reduced shrinkage and less creep. This results in lessened labor time and dependence upon reinforcing steel. According to iCrete, Quadrozzi was actually able to reduce the amount of cement used through the use of their product.
"The world is watching as we build the Freedom Tower," stated Daniel R. Tishman, chairman and chief executive officer of Tishman Construction Corporation, construction manager of the Freedom Tower. "From the very core of the building to the top of the spire, we're using the best products, construction practices and processes available today, and that includes iCrete. With its technology, the iCrete System produces a stronger, more cost effective concrete that is environmentally sensitive. In fact, this is the highest strength concrete ever poured in New York - beating the previous record of 12,000 PSI."
Both the tower, as well as the 186-foot inner safety core supporting the superstructure, will be built with The iCrete System.
"iCrete technology gives us the confidence that we have the best concrete to build the Freedom Tower, the most important building we've ever constructed," agreed Renzo Collavino, president of Collavino Construction.
The iCrete System, a patented state-of-the-art technology, will be used to produce 240,000 cubic yards of concrete for the Freedom Tower. During the design phase of the project, the building's engineers required concrete used in the Freedom Tower to achieve a record breaking 14,000 pounds per square inch (PSI) of compressive strength. In addition to physical and material benefits, iCrete also offers environmental benefits. Since less cement is required for the iCrete System, harmful carbon dioxide emissions are reduced by up to 40% -- another industry breaking record.
iCrete's management team has a wealth of experience within the concrete and construction industry. The company's CEO, Juan Carlos Terroba, was formerly chairman of the largest independent concrete producer in Mexico, Productos Cementeros Mexicanos. The Freedom Tower project has proved to be a boon for this relatively new company. Less than one year after iCrete was introduced at Freedom Tower, it has already been poured at more than 30 construction sites in the Greater New York Metropolitan Area, including Midtown, the Upper West Side, Lower Manhattan, and Tribeca.