Taking Down the Brick Wall

On-site recycling of aggregate material is a common practice in the construction and demolition industry. Contractors often crush and screen asphalt or concrete generated from their work to create a product they can use as backfill or foundation for buildings or roads. The denseness of concrete and asphalt make these materials well-suited to these applications.

While the practical uses of recycled asphalt and concrete are well established, the significantly lower density of brick has hindered the material from being recycled on site and used as backfill.

“If you are a contractor who has been hired by a developer to come in, there is a little bit of hesitation [for using brick] because they look at the brick and this stuff blows up; it disintegrates because it’s not very dense,” says Bill Royce, president of Eagle Crusher, based in Galion, Ohio. “Do I want to use crushed brick to go under my road or under my building? The answer to that is pretty much, ‘No.’”

While recycled brick may not be ideal for use as backfill for roads or buildings, several end markets for the material have emerged, primarily in landscaping applications. As a result, some contractors have increased their focus on crushing and recycling brick into saleable end products and, in the process, have boosted revenue.

“Most guys aren’t really going to say ‘I want to crush brick to pay my bills,’” says Royce. “Like anything else, with the concrete or the asphalt, a contractor will always look for a different market and a different revenue stream for his machine,” he adds.

THE CRUSHING PROCESS

For contractors considering processing brick into an end product, an impactor crusher can be better-suited for the task than a jaw crusher, according to several C&D recyclers.

“An impact crusher is mainly used to crush many kinds of large-, medium- and small-sized hard materials,” says Tim Lee, site manager for Kurtz Bros. Inc., a C&D recycler based in Cleveland. He says an impact crusher tends to remove more mortar from the brick than a jaw crusher, which is primarily used in mine or ore processing plants.

Stamford, Conn.-based Cavaliere Onsite Recycling also uses an impact crusher to process brick. “With an impactor, the finished product delivered from the machine is more cubical, and we can adjust the amount of fines-to-aggregate ratio by adjusting feed hopper speed and the rotor rpms,” says D.J. Cavaliere, operations manager for the company, which also acts as a distributor for Rubble Master equipment.

When crushing brick material, contractors must be aware of the difference in density between brick and the concrete and asphalt material they may be more accustomed to crushing. “Say a contractor has a normal setting on an impactor, where the concrete will come out at 1 inch, 1.5 inches,” Royce says. “In that same setting the material would probably come out at near 0.25 inch. The brick, by itself, is not as dense and not as secure as a piece of concrete with the aggregate, the binder and the rebar or mesh,” he adds.

Additionally, the lower density of brick will also affect the output of a contractor’s crusher. Cavaliere indicates that when using a crusher to process brick, generally output will be greater in volume, but less in tonnage per shift when compared with processing concrete or asphalt using the same crusher.  

Recyclers report that the mortar contained in bricks causes little hassle in the crushing process. “The total amount of mortar visible in the final recycled product is greatly reduced when mortar is crushed along with brick, however a slight amount is still visible,” says Lee.

According to contractors, common screening configurations downstream from a crushing plant may include two- or three-deck screens to produce a variety of products, depending on the demand in a given market.

ON SITE OR OFF SITE

While the lower density of recycled brick may cause skepticism among developers who do not want to use it as a foundation for roads or buildings, there are still some markets where it makes sense to crush and recycle brick on site.

Although government jobs may not allow brick to be used in any capacity as a backfill, if the brick is blended with other aggregate material such as concrete, it can be used for foundations, especially when processed by an impact crusher, according to Royce.

“If they are just dumping it down as back fill, there is still some benefit [of using an impactor] because now that the product is cubicle, when you mix the fines in there, it packs just like concrete and just like asphalt,” Royce says.

Lee says Kurtz Bros. does some onsite brick crushing for structural fill jobs and landscaping, while Cavaliere says his company most frequently processes bricks off site, but does complete some specialized on-site jobs, depending upon the amount of brick to be processed.

“For our crushing equipment, we can easily mobilize to a site as small as 200 to 300 yards,” Cavaliere says.

Whether crushing bricks on site or off site, careful attention must be paid to the condition of the bricks resulting from a construction or demolition operation. In some instances, the state in which a contractor is operating may affect whether it is economical to crush and recycle bricks into new products.

“The reason bricks are not crushed more often has to do with contamination and state regulations,” says Cal King, general manager of Chicago-based mixed C&D processor Recycling Systems Inc. “If paint or another material is on any of the bricks and contains any trace of hazardous materials, the whole load becomes unsalvageable. Due to the high volume of this occurrence, we tend to avoid the process of crushing bricks and allow others to handle it.”

So long as recyclers ensure that they are not violating any governmental regulations by recycling bricks, they can find several emerging markets for crushed brick products.

A NEW LANDSCAPE

While bricks are not always well-suited for use as backfill on construction projects, contractors actively pursuing end markets for recycled brick products can find viable options in the landscaping industry.

Recycled brick products can be used for walkways, rooftop applications, parking lots, driveways and as an alternative to mulch, according to Lee. “An emerging niche market in the industry is for historical bricks—antique brick may be separated out and used for residential, landscaping and commercial products,” Lee adds.

Because of its rich color, recycled brick chips may even have an advantage over more traditional wood mulch.

“For a lot of the guys who use decorative stone or brick, if the weeds keep coming up, it’s good for that,” Royce says. “It’s heavy and it’s not going to blow away versus the mulch. Plus, it will keep its color,” he adds.

Additionally, Royce adds that, in some instances, contractors may want to consider a wash screen or finishing screen to remove the mortar, further enhancing the color of the finished brick chip product. He says, “It will add to a guy’s costs, but if he knows there is enough of a market where he’s at to go that extra mile that he could offset the cost of adding that final screen, then he might do it.” Royce adds, “If he can adjust that with a price in his market, it can pay for itself with so many tons running through it.”

Most commonly, brick-derived products are sold directly to commercial landscaping companies for use in their contracted residential and commercial jobs. However, there may be opportunities to market the product directly to consumers through home improvement retailers.

“I’ve seen brick chips before in the Home Depot and Lowes with bags of decorative stone and brick that homeowners can [purchase],” says Royce.

Aside from using crushed bricks in landscaping applications to improve aesthetics, some recyclers are finding the material also can offer other practical advantages in such applications.

“The dust or the fines can be used for dust control and on baseball fields with the clay mix,” says Cavaliere. “I feel the brick dust can also be used as dust control on dirt and gravel roads and can be easily applied by a city or town sand/salt spreader.”

As end markets for recycled brick products continue to emerge and develop, construction and demolition contractors have a greater incentive to take a hard look at their current operations. By optimizing the use of their crushing and screening equipment, contractors can reclaim some value from the brick components in their material streams.    

The author is assistant editor of Recycling Today. This feature originally ran in the Jan./Feb. 2010 issue of Construction & Demolition Recycling, a sister publication of Recycling Today.