Council on Tall Buildings and Urban Habitat
 

 CTBUH Gains Info on Concrete Recycling at Bluff City

July 10, 2013

See more on the research project
See more about the CTBUH research division
CHICAGO - The CTBUH research team trekked to Bartlett, IL to visit Bluff City Materials and meet with M. Slade O’Keefe, Vice President of Engineering and Construction. This meeting is another in a series supporting the Life Cycle Assessment of Tall Building Structural Systems research project funded by ArcelorMittal. Bluff City Materials takes in clean, broken concrete for recycling, which is then sold to contractors. The purpose of the meeting was to gain a greater understanding of the amount of energy that goes into recycling concrete, along with the volume of concrete recycled on a daily, monthly, and yearly basis.
View of Bluff City with piles of recycled concrete, asphalt, and shingles
The CTBUH research team kicked off the meeting by briefing O’Keefe on the life cycle assessment (LCA) project and its objectives. O’Keefe then educated the research team about the three main Bluff City Materials locations in the Chicago area. Each location brings in about 20 tons (18.1 metric tons) of concrete daily. This concrete is recycled through a crushing method, in which the aggregates are removed and used for roadways.  Bluff City Materials has a working relationship to supply gravel to the Illinois Department of Transportation (IDOT). O’Keefe also described the process for separating rebar from concrete. The specific information on energy consumption and transportation gained by the team is expected to prove invaluable for a more complete study.
The CTBUH at Bluff City. Left to Right: Dr. Payam Bahrami, M. Slade O'Keefe, Meysam Tabibzadeh, Dr. Dario Trabucco, Afshin Zahraee
Mr. O’Keefe then went into detail as to why concrete recycling machinery is making a switch from diesel to electric power in the current economy. Some locations and plants have made the switch, while others have not. This variance will play a role in the CTBUH researchers’ analysis of the concrete recycling process.

In addition to crushing and recycling concrete, Bluff City Materials also recycles asphalt and shingles, O’Keefe said. In some cases, the company has made a concrete-asphalt blend and is currently testing the market for the material. In general, concrete spends about four to six months at Bluff City as it is recycled, crushed, and shipped back out to third parties.
After the enlightening meeting, O’Keefe took the CTBUH research team onsite to see the recycling process firsthand. He displayed the recycling of asphalt and shingles, which first passed through conveyor belts, were then sorted by manual laborers, and finally run through a crusher. Aggregate piles were seen in abundance throughout the yard, testifying to Bluff City’s business recycling surplus concrete into stone. In an eye-popping revelation, O’Keefe revealed that Bluff City, along with other similar entities, uses several thousand gallons of water a day to keep its operation running.
Crushed concrete onsite
Overall, the meeting and tour were extremely helpful and revealing.  The CTBUH research team plans to incorporate this new body of knowledge into an extensive LCA of tall buildings.