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O&G Industries' ready-mixed concrete division has been using Pozzotive as a supplementary cementitious material for a year and a half.

Louis Grasso Jr. speaks almost romantically when recalling how he became involved with a new way of manufacturing block and brick at his plant in Kingston, N.Y. “It's been an 11-year journey for me,” he says. “This is not the flavor of the day. I have 11,000 hours of my personal time invested in this.”

Grasso is referring to Kingston Block & Masonry Supply's development of Pozzotive block and Pozzotive Plus brick, which use post-consumer glass as a supplementary cementitious material (SCM). He recalls attending a National Concrete Masonry Association conference in Chicago. “Most of our industry at the time was stuck in 1968,” he says. “Everyone was trying to figure out how to find ways to participate in this renaissance in the construction industry in terms of LEED and sustainable development.”

About the same time, architect Robert Fox Jr., partner of Cook+Fox Architects who worked on the 945-foot-tall Bank of America building in Manhattan, touted by some as the world's greenest office high-rise, met with Grasso. This was just after Grasso, his father Louis Grasso Sr., brother Patrick Grasso, and business partner Elliot Kracko opened their block manufacturing plant in Kingston, about 100 miles north of New York City on the Hudson River.

Expecting to receive the architect's praise, Grasso took some block samples to Fox's office. The architect said they looked fine, but then added that he couldn't use them.

“I was a little perplexed and disappointed,” Grasso recalls. “He said to find a way to make them sustainable and to incorporate recycled content so they could contribute to sustainable development. I took that challenge very seriously. He gave me the kick in the pants that challenged me to find a way to manufacture a green product, and we did. It's been a game changer for us.”

Fixing a bottleneck

Glass has been a bottleneck in recycling for many years. (Pardon the pun, Grasso says.) Eighty percent of all post-consumer glass gets landfilled. This material is not biodegradable, so it sits in landfalls forever. Between 12 million and 13 million tons of this material enters U.S. landfills a year.

To make a product suitable for Pozzotive block and brick, glass is pulverized, and then washed, dried, and further reduced in size. In the final stage, this material is fed into a ball mill, where it is finely ground to 15 microns in size. The post-consumer recycled aggregate used for the Pozzotive Plus brick is derived from recycled concrete. Using Pozzotive products can help projects obtain recycled content and regional material credits toward achieving U.S. Green Building Council LEED certification.

“It's a wonderful example of using a material that would have been land-filled and using it for a much higher and better use, and getting it out of the waste stream,” says Grasso. “Unlike other pozzolans, in the end, it doesn't contain any heavy metals. It's all post-consumer, and it's all derived regionally.” The material is manufactured in Coeymans, N.Y., and is shipped to Kingston Block by tanker.

“Everything we do with Pozzotive and everything we've done at Kingston speaks to regional manufacturing,” he adds. “The material is harvested regionally and made into feedstock for a regional manufacturer to make a regional end-product that contributes to a regional project.” Kingston also boasts that manufacturing one ton of Pozzotive prevents one ton of carbon dioxide from being released into the atmosphere in the cement manufacturing process.

Grasso points to Pozzotive block's and brick's added strength as a major selling point. This material replaces 30 percent of the portland cement in Pozzotive products, and the particles' size distribution provides the added strength.