Making Construction and Demolition Waste Work Towards a Sustainable Future

By Luke Carothers

In 2018, the Environmental Protection Agency (EPA) released a report stating that nearly 600 million tons of construction and demolition waste was created in the United States, which is more than double the amount of municipal waste that was generated during the same time.  Construction and demolition waste includes materials such as concrete, wood from buildings, asphalt from roads and roofs, gypsum from drywall, metal, bricks, glass, plastics, salvaged building components, trees, stumps, earth, rocks, etc.  According to the same report from the EPA, 455 million tons of this construction and demolition waste was directed to next use, and 145 million tons of the waste was sent to landfills.  The waste that was directed towards next use was primarily used as landfill, according to the report.

One company leading the charge to find new ways to use construction and demolition waste is LafargeHolcim and their subsidiary, Geocycle, who are partnering with the US Army Corps of Engineers’ Engineer Research and Development Center (ERDC) to study how these materials can be used for energy recovery and mineral recycling.  The goal is to demonstrate how construction and demolition waste may be used to create alternative fuels and alternative raw materials for the production of new, more sustainable construction materials.  This agreement means that the US Army Corps of Engineers, LafargeHolcim, and Geocycle will be working cooperatively, sharing important information and working together to come up with solutions with a project cost of $3.4 million.  

The first step in the agreement is to complete a waste-characterization study, which means that the teams must first work together to identify a set of bases that have a potential number of construction projects or have enough construction and demolition waste already that would be suitable for the study.  Once these bases have been identified, the teams at LafargeHolcim and Geocycle with work alongside with the ERDC to study this waste to understand the volumes as well as the chemistry of the waste streams in order to determine how to translate that chemistry into either heat content for energy recovery or mineral recycling to create alternative raw material for the cement manufacturing process.

The waste-characterization study is crucial in that construction and demolition waste on a military base typically differs from that produced during a commercial or residential project.  This is due to not only a difference in building materials, but also to the speed and age in which these military installations were built.  As such, the teams must identify what buildings are being taken down, what materials are in those buildings, and how much of that material is being created.  The next step is to take this information to the lab to determine the chemical properties of each of those waste streams.  Using the tools and resources at their disposal,  the teams will then determine what materials are suitable as a heat source for the kiln or use in the manufacturing process to reduce the use of raw materials such as limestone.

The teams at LafargeHolcim, Geocycle, and the US Army Corps of Engineers’ ERDC will utilize many tools and resources to complete their research.  The teams will have access to facilities such as Geocycle’s Holly Hill Research Center in South Carolina.  Geocycle is an industry leader in co-processing and developing waste management solutions.  The teams will utilize not only Geocycle’s processing and co-processing capabilities, but also their labs and expertise to develop a heat and fuel analysis.  The teams will also have access to Holcim’s Global Innovation Center, located in Lyon, France.  At the Global Innovation Center, the teams will have access to modeling capabilities that allow them to see what alternative raw materials can be used in the manufacturing of clinker.

If this research and testing is successful, the teams at LafargeHolcim and Geocycle hope to continue working with the US Army Corps of Engineers to develop a large-scale pilot program based on the outcomes of this partnership.  The success of this partnership has a strong potential to positively impact the overall re-use of construction and demolition waste in the United States.  As military installations across the country continue to age and be replaced at an increasing rate, this research will be crucial in shaping construction and demolition projects as we work towards a more sustainable future.     

Luke Carothers is the Editor for Civil + Structural Engineer Media. If you want us to cover your project or want to feature your own article, he can be reached at lcarothers@zweiggroup.com.