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comment iCrete Mixes Stronger Concrete With Less Cement
iCrete, based in Beverly Hills, California, has developed a proprietary algorithm for designing concrete mixes that it says can reduce portland cement content by 10 percent–40 percent without compromising strength. Cement production is energy-intensive; in a concrete mix with 12 percent cement, the cement is responsible for 92 percent of the embodied energy of the mix. In addition, extra cement usually increases early strength gain but can compromise long-term durability and cause other problems. iCrete uses an analytic process to optimize cement content to maintain or increase strength without any special admixtures.
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iCrete does not offer a product, rather an approach to mix design. The company’s business model is based on licensing its know-how to ready-mix and precast concrete plants. Tom Schneider, iCrete’s vice president for sales, marketing, and operations, says the company studies the aggregates available to each plant it works with, analyzing the gradations of aggregate very closely: “Every three-quarter-inch rock is not the same,” Schneider says. With that analysis, iCrete designs the mix to optimize—not maximize—particle packing. Packing the aggregate tightly creates smaller voids with less room for cement paste, yielding a mix that is both strong and workable. Special characteristics such as ductility or compressive strength can also be optimized.
A key part of iCrete’s service is quality control. Each authorized mix plant is “fingerprinted” through a study of its equipment and procedures, and each batch is monitored for about 20 variables via data from scales and flow meters. Water content gets particular attention. iCrete receives this data in real time, and if the mix is deviating from the prescribed formula, the company contacts the plant to stop the batch before it is sent to its destination, reducing waste from rejected batches. “You’d be amazed how many ready mix plants don’t utilize this data and good quality control,” Schneider says.
“It’s not a bag of magic stuff,” Matthew Sherman, P.E., of New York engineering firm Simpson, Gumpertz, and Heger, says of iCrete. “What they’re adding is knowledge.” Schneider confirms that iCrete’s mixes usually contain only standard ingredients, including fly ash, although a client who requests special additives will be accommodated. “We’re admixture agnostic—we work with them all.”
iCrete mixes have been used in high-profile projects such as the Freedom Tower at the World Trade Center site in New York City, where a concrete that combines extremely high strength, high elasticity, and a low heat of hydration was needed for the massive core walls. The company’s mixes are being used for run-of-the-mill projects as well. Schneider says that although iCrete’s approach introduces extra costs, the savings in cement make it cheaper than standard concrete. According to Sherman, whose firm designs custom concrete mixes as an ancillary part of its engineering services, ordinarily only a very large project can justify the expense of using a specially designed mix; iCrete has the potential to make customized mixes more widely available at a reasonable cost.
Schneider says iCrete’s mixes are currently available throughout North America and in the Middle East, with plans in place to expand to other regions. He expects the company to have authorized 150 plants by the end of 2009.
Copyright 2009 by BuildingGreen, LLC
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