For more than a decade, New Rochelle, New York-based Urban Mining Industries has been advancing a new use for recycled glass in the form of Pozzotive, a ground glass pozzolan used in concrete production. Like other artificial pozzolanic materials such as coal fly ash, ground glass can assume cement-like qualities when it reacts with a combination of water and cement. Patrick Grasso of the Grasso family, owners of Urban Mining Industries, says Pozzotive strengthens concrete and lowers CO2 emissions. In using locally sourced glass, Pozzotive also has ushered in a circular economy for the glass industry in Connecticut, where it is now being made.

Grasso, a partner with Urban Mining Industries, says his family has long been involved in the construction industry. The Grassos’ story starts more than 15 years ago with the family first obtaining a block manufacturing plant in upstate New York. After rebuilding the plant, they used it to make grey construction block. Louis Grasso Jr., Patrick’s nephew, wanted to find a way to distinguish their gray block from every other gray block made in America. After Louis was advised to include recycled content in the block, a series of trial-and-error tests were done to find a material that could meet this goal. It was decided that glass was the best choice. After realizing the use of bigger chunks of glass wasn’t the best approach, they eventually created a fine powder of ground glass that became Pozzotive.

“So, as a result of that block manufacturing plant, we were able to see the market way back then when no one else was willing to experiment with this kind of stuff,” Patrick Grasso says.

Pozzotive in Action

The magic of Pozzotive’s effect in concrete, Patrick Grasso says, starts with a chemical reaction when it is paired with water and cement. Before Pozzotive becomes involved, the hydration of cement introduces two key compounds. One is calcium silicate hydrate (CSH), which Grasso says is the “glue” that develops the concrete’s strength. The other product is calcium hydroxide (CH), which conversely weakens the concrete and causes porosity. When a ground glass pozzolan is introduced, it gives up a silica atom and joins the CH to become CSH. This pozzolanic reaction allows ground glass to gain cementing properties and act as a partial replacement to cement. In most mixes, Pozzotive replaces 20 or 30 percent of cement.

Photo courtesy of Urban Mining Industries

Initially, Pozzotive was produced in small quantities at a product validation plant in New York. Before 2022, the company was mostly focused on getting a solid footing in the pozzolan market. It took four years, Grasso says, to obtain an ASTM 1866 standard that specifically confirmed the viability of ground glass pozzolans in concrete. This process involved a committee of industry professionals that vetted and signed off on 3^rd party testing done with Pozzotive.

Since its inception, Pozzotive has been used in projects at various locations, most of which are in New York and Connecticut. Some of these include the ESPN Digital Center 2, the New York Police Academy and the Second Avenue subway station in Manhattan. During the UN General Assembly Building’s renovation, 60 tons of window glass were harvested from the building and used to create pavers with Pozzotive for the UN Plaza. Grasso says smaller projects in Connecticut that have used Pozzotive, including Ox Ridge Elementary School in Darien and New Canaan Library in Canaan, particularly demonstrate the significance of Pozzotive in building a local circular economy.

Impacting Industries

In addition to supporting a circular economy, Patrick Grasso says Pozzotive addresses other challenges in the glass recycling industry: the cleaning and separating of glass and costs associated with transporting and logistics if a processor is not nearby. A common route for recycled glass is turning it back into bottles, but complications can arise in this process as the glass needs to be separated by color and any ceramics need must be removed because of their different melting temperature. The color of the glass does not affect Pozzotive, and pieces of ceramics are welcome since they are pozzolanic as well. Pozzotive also can use glass from electronics that don’t contain lead, plate glass and demolition glass. The glass is taken through a cleaning and separating process and is milled into a pozzolan that is 95 percent smaller than 325 mesh, Grasso says.

A primary issue within the cement industry, Grasso says, is CO2 emissions. Cement production accounts for about 7 percent of all global carbon emissions, and the U.S. alone uses more than 100 million tons of cement per year, he says. Twice as much concrete is used in construction than wood, plastics and aluminum combined. Even though common postindustrial cement replacements such as fly ash and slag, which is residue from steel manufacturing, can create a lower carbon concrete, Grasso says he considers postconsumer ground glass an even better replacement.

“A glass bottle is a glass bottle pretty much anywhere in the world in terms of its chemical composition … you can make a very consistent finished product because of the feedstock you’re starting with,” he says.

Grasso says that every ton of cement generates almost a ton of CO2. Urban Mining Industries has done testing to replace up to 50 percent of cement in concrete with Pozzotive, reducing the carbon footprint by almost a ton–for–ton basis of the cement it replaces, he says.

Photo courtesy of Urban Mining Industires

Pozzotive has other benefits that exhibit how it enhances performance of concrete along with its sustainable qualities. Concrete with greater percentages of Pozzotive feature a brighter white color, meaning it can reduce the heat island effect in urban areas, where temperatures are higher in light of a greater abundance of manufactured surfaces that absorb heat. Grasso says Pozzotive does a greater job of preventing efflorescence—when a white powdery substance bleeds out of concrete—and shrinkage, which means less cracking. He says concrete with Pozzotive is five-times more powerful in reducing moisture and chloride penetration than a straight cement mix.

“I think it’s a holistic solution, a climate solution, a health solution—avoiding heavy metals and some of these other alternatives … and the circular economy issue about really just taking regenerative waste streams regionally and putting them back into those regions,” he says.

The Future of Pozzotive

Pozzotive has been used by different companies and organizations, including Torrington, Connecticut-based ready mix company O&G Industries. T.J. Oneglia, vice president at O&G, says he believes the use of pozzolans in general is likely on the rise in the concrete industry. Oneglia points to recent trends of using more recycled material and lowering buildings’ carbon footprint.

“I am seeing support in our local market from the designers, the architects, the engineers and also the owners and the end users of the concrete. [There is] a desire to build green, and so Pozzotive, just by its very nature, in my opinion, is greener than the other sources of materials,” Oneglia says.

Ground glass pozzolans in particular could experience higher demand due to potential supply issues with other pozzolans, Oneglia says.

He says O&G plans to continue using Pozzotive mixes, which are starting to be specified on school projects and municipal projects.

“We intend to supply it as an ingredient in our concrete wherever and whenever it’s specified,” Oneglia says. “And then, in addition to that, we intend to use it just as a part of our daily concrete when we’re able to.”

Patrick Grasso says Urban Mining Industries’ focus is now on further commercializing Pozzotive and using it for bigger projects. The first large scale Pozzotive plant was established in Beacon Falls, Connecticut, in 2021. Grasso says this is a good central location from a glass feedstock perspective and allows Urban Mining Industries to serve the greater metropolitan New York market while also expanding into the Boston market. The new facility will allow the company to produce an estimated 50,000 tons of Pozzotive, Grasso says.

“We had to go through this four-year process of getting an ASTM standard. And we’ve had to have this product in use now for over 10 years to make sure it wasn’t some fly-by-night thing, it was real. We had to have the first plant up that can produce it commercially, large scale, and so all of those steps are now in place. So, any market where there is a need of a glass solution of some reasonable size, we can be there,” he says.

Cleveland-Cliffs Inc. has reported second-quarter 2022 consolidated revenue of $6.3 billion, representing a 26 percent increase compared with 2021 second-quarter revenue of $5 billion.

The company’s second-quarter net income of $601 million included deductions for one-time charges for debt extinguishment, accelerated depreciation related to idling a coking facility in Middletown, Ohio, and some severance costs. Thus, the firm’s income fell 24.4 percent from $795 million one year ago.

Lourenco Goncalves, Cleveland-Cliffs board, president and CEO says, “We were able to achieve our largest quarterly debt reduction since our transformation began a couple years ago while delivering substantial capital returns via share repurchases. As we move into the second half of the year, we expect this healthy level of free cash flow to continue, as a result of declining capex needs, the accelerating release of working capital, and the heavy use of fixed-price sales contracts. In addition, we expect to see further significant increases in the average selling prices for these fixed contracts resetting on Oct. 1.”

Goncalves adds, “Our industry-leading exposure to the automotive sector separates us from all other steel companies in the United States. With automotive demand outpacing production for more than two years now, the consumer backlog for cars, SUVs and trucks has become enormous. As supply chain problems continue to be resolved by our automotive clients, pent-up demand for electric vehicles continues to increase, and light vehicle manufacturing catches up with demand, Cleveland-Cliffs will be the primary beneficiary among all steel companies in the U.S. This important distinction of our business relative to other steel producers should become clear as we progress through the remainder of this year and into next year.”

In a conference call with steel sector analysts held late last week, Goncalves also noted, “We are seeing a lot less competition for prime scrap. At the beginning, we had to really fight to get the deals done. But now, apparently, the competition is not really looking for a prime scrap. They should have their reasons. To be honest with you, I don’t care. For us, prime scrap is important. We prefer to use prime scrap. Prime scrap allows me to use less cook and using less coke to generate less CO₂, and that's a good thing. And prime scrap that I use coming from automotive to go back to automotive in the steel that I produce is great to create a closed loop solution with our clients, and there’s a value on that.”

Last year, Cleveland-Cliffs cited access to prime scrap as a key reason for its acquisition of Detroit-based Ferrous Processing & Trading (FPT).

Although in a previous earnings call Goncalves had hinted at possible additional electric arc furnace (EAF) melting capacity, last week he said, “There’s no EAF coming at Middletown. We are good with the footprint that we have. We are probably the most environmentally friendly blast furnace operator in the entire world.”

The Construction & Demolition Recycling Association (CDRA) has announced the 9th Shingle Recycling Forum has been scheduled for Oct. 5-6 at the Loews Chicago O’Hare Hotel.

CDRA says the event is designed to bring together state Department of Transportation (DOT) officials, recyclers, asphalt plant operators, road pavers and other interested parties “for impactful networking and cutting-edge presentations from industry experts.”

The Maryland-based Asphalt Roofing Manufacturers Association and Arkansas-based Paragon Resource Management are sponsors of the event. Additional exhibitors and sponsors are being sought by CDRA, the group adds.

A schedule for the October event indicates a facility tour will be offered to attendees. Topics to be covered include: the state of recycled shingle use in pavements; guidance from the Federal Highway Administration (FHWA) on the use of recycled asphalt shingles (RAS) in highways; working with state DOTs to Use shingles in the highway environment; and panel discussions offering contractor perspectives and a review of other process shingle end markets.

Rubber is meeting road not in the usual sense of tires rolling on pavement but in rubber from scrap tires becoming part of road surfaces in some areas of Michigan.

Recent paving projects backed by the Michigan Department of Environment, Great Lakes, and Energy (EGLE) in Bay and Clare counties are expanding Michigan’s use of rubber tire scrap in road resurfacing, keeping the materials out of landfills and shaping the highways of the future.

Elsewhere, plastic scrap has been integrated into asphalt as companies become more creative in finding end uses for plastic, rubber and other materials that have proven challenging to reuse in the past.

The projects in Bay and Clare counties also highlight a Michigan recycling milestone. As of 2022, the state’s major scrap tire processing businesses—about 10 in all—no longer send any regular scrap materials to landfills. Apart from small quantities too dirty or contaminated to be recycled, all the material is recovered and repurposed for use not only in road work but also as mulch and in rain gardens and septic fields; as weights for construction barrels and silage covers; in molded and extruded plastic products; as porous pavement for trails and pathways; and as tire-derived fuel.

“The scrap tire market in Michigan is in a transformation from managing scrap tires as a waste to creating economic value,” says Kirsten Clemens, scrap tire coordinator in EGLE’s Materials Management Division.

The repaving in Bay and Clare counties used material from about 59,500 tires on more than 5.5 miles of roadway. EGLE awarded Michigan Technological University a $396,000 grant for project design and testing. Each county’s road commission performed the paving work, resurfacing 4.5 miles of Seven Mile Road from E. Midland Road to E. Beaver Road in Bay County and 1.15 miles of W. Haskell Lake Road from Cook Avenue to Lake Station Avenue in Clare County. At both locations, the repaving was divided into sections to enable side-by-side comparison of the rubberized and conventional paving materials.

These two are far from the first such projects in Michigan. Last year alone, four Michigan counties completed rubberized local road projects using scrap from more than 30,000 tires. As far back as 2005 and 2006, Saginaw County rolled out a pair of 2-mile sections of rubberized asphalt. The Michigan Department of Transportation allows a portion of asphalt mixes to be recycled materials, but it is not required.

“We have about 20 years of projects, and we’ve got some really solid technology now,” Clemens says. “What we’re trying to do is expand the use by getting the material into the communities that need infrastructure solutions.”

The growing consensus is that rubber-modified paving is a winner for local roads. In 2019, EGLE helped fund a Michigan Tech project in Dickinson County to see how an asphalt-rubber mix would hold up to extreme Upper Peninsula weather. A study two years later found the pavement resists rutting during hot weather and cracking in the cold. Researchers will continue monitoring the project—which won a 2019 County Road Association of Michigan award—for 10 or more years.

Installation of rubber modified chip seal on Seven Mile Road in Bay County.