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Incorporating sustainable practices in flooring selection, including optimizing concrete mixes and reducing the carbon footprint of materials, will benefit both the environment and the facility’s bottom line.
By Vincent Beyer

Designing and maintaining floors in solid waste processing facilities such as transfer stations, waste-to-energy plants, and recycling centers presents unique challenges. These facilities, originally designed to handle specific waste volumes and types, are now tasked with managing more waste, often more diverse, than originally anticipated. As a result, the floor systems in these facilities experience accelerated wear, leading to frequent maintenance and, in many cases, premature deterioration. Additionally, building new facilities has become more challenging due to evolving regulatory and permitting requirements, leading to the extended use of existing facilities, often beyond their expected lifespan (see Figure 1).

Challenges in Floor Durability
Solid waste processing facilities are exposed to dynamic and demanding conditions. Floors must withstand abrasive forces, chemical attacks, and heavy impacts. This wear and tear primarily arises from the constant movement of materials, the type and volume of the waste stream, and the use of heavy equipment. Given these factors, durability is a primary concern when selecting materials for flooring in such environments.

Over the years, different flooring approaches have been employed, with mixed results. Concrete floors are typically specified for the initial construction of solid waste facilities due to their strength and durability. However, as waste volumes and material diversity increase, so too does the rate of deterioration (see Figures 2 and 3).

Evaluating Floor Sustainability
From a sustainability perspective, the long-term performance and environmental impacts of flooring systems are critical. The longevity of the flooring material directly correlates to its sustainability. A durable floor requires less frequent maintenance and replacement, reducing the facility’s overall carbon footprint. The key to sustainability lies in choosing flooring materials that maximize performance while minimizing environmental impact.

In most cases, the installation of concrete floors is the first step in constructing a solid waste facility. The type of concrete used significantly influences the longevity of the floor. The anticipated waste volume, as well as the type of waste, determines the level of abrasion and impact the floor will endure. Importantly, concrete production—especially the cement component—has a considerable environmental impact, as cement production is one of the largest global contributors to carbon emissions (see Graph 1).

Concrete Mix Design: Impact on Durability and Sustainability
A concrete mix’s durability in solid waste facilities is influenced by several factors, including the type of cement and aggregate used. Research conducted by North Carolina State University (NCSU) in 2018 found that high-strength concrete, specifically 7000 PSI concrete with granite aggregates, provided superior wear resistance and strength, improving resistance to both abrasion and leachate attacks.

This study aligns with findings from other organizations, engineering firms, contractors, and testing agencies, all of which emphasize the importance of selecting the right concrete mix for high-performance flooring in waste processing facilities. As facility owners seek to minimize maintenance costs and the environmental impact of concrete, using high-strength mixes with appropriate aggregates is vital.

The Role of High-Performance Toppings
While concrete floors are the initial choice for solid waste facilities, high-performance cementitious toppings have become a popular solution for restoring worn floors. These toppings are often used as overlays to repair damaged concrete or incorporated into the design of new floors to enhance durability. The toppings typically use metallic aggregates or natural aggregates, such as trap rock, emery, and calcined bauxite, combined with high-strength cementitious binders.

These specialized overlays offer enhanced resistance to abrasion, impact, and chemical damage, providing a more durable surface than standard concrete. The use of these high-performance materials helps extend the life of floors in facilities that experience intense wear.

Environmental Impact of Concrete Production
As previously noted, cement production is one of the largest sources of greenhouse gas emissions globally. Concrete is the second most widely used material in the world, after water, contributing significantly to environmental degradation. The cement industry has made strides to reduce emissions by adopting limestone clinker in cement production and using more sustainable materials such as slag and fly ash in concrete mixes. Additionally, reducing the amount of steel reinforcement used in concrete slabs can also decrease carbon emissions, as steel production is another significant contributor to greenhouse gas emissions.

Research has focused on developing concrete mixes that use less cement without compromising performance. This is achieved through the incorporation of alternative materials and technologies like structural synthetic fibers, which can replace a portion of steel reinforcement. The sustainability of concrete flooring systems is thus closely linked to innovations that reduce both cement and steel consumption while maintaining or improving long-term durability.

Sustainability Factors in Flooring Selection
Sustainability in the context of solid waste facility flooring involves not only the durability and longevity of materials, but also the environmental impact associated with their production and maintenance. Several factors should be considered when evaluating the sustainability of different flooring systems:

• Life Cycle Assessment (LCA): This tool helps evaluate the environmental impact of flooring materials across their entire lifecycle, from production to installation and eventual disposal or replacement.

• Carbon Footprint/Embodied Carbon Impact: Cement and steel production are major contributors to carbon emissions, so minimizing their use in flooring systems can significantly reduce a facility’s environmental footprint.

• Global Warming Potential (GWP): GWP measures the potential contribution of materials to global warming, which is a critical consideration when evaluating the sustainability of flooring options.

Sustainable flooring solutions should balance long-term performance with minimal environmental impact. The more durable a flooring system is, the fewer resources and materials will be required for maintenance or replacement, leading to lower carbon emissions over time (see Graph 2).

Case Study: Environmental and Economic Benefits of High-Performance Toppings
A real-life example helps illustrate the impact of flooring choices on both environmental and operational costs. A solid waste facility processing 300 to 500 tons per day (TPD) faced significant wear on its concrete floors due to heavy equipment and abrasive waste materials. Over 16 years, the facility completed three concrete removal and replacement projects on the same 7,500-square-foot area. The carbon emissions associated with the concrete and steel components of these projects totaled 282 metric tons—this does not include emissions from construction equipment or demolition activities.

By contrast, a high-performance calcined bauxite topping, which would have been installed just once over the same period, would have emitted only 16 metric tons of carbon and could have lasted 15 to 20 years. The significant reduction in carbon emissions highlights the environmental benefits of choosing long-lasting, high-performance toppings over frequent concrete replacements.

Long-Term Economic Considerations
In addition to environmental impact, long-term cost savings are an important consideration for facility owners. Replacing concrete floors multiple times over a facility’s lifespan can result in substantial financial costs—not only for materials and labor, but also due to downtime during the repair process. In many cases, facilities may need to divert waste to other processing plants or landfills during major repairs, incurring additional transportation costs and lost revenue from tipping fees. High-performance toppings, which can be installed quickly and require minimal downtime, offer an economically viable alternative by reducing both operational disruptions and the need for frequent repairs.

Making the Right Flooring Choice
Choosing the right flooring system for solid waste facilities is not a one-size-fits-all decision. The key factors influencing the choice include the waste volume, types of materials processed, and the specific environmental conditions of the facility. Owners must consider the durability, environmental impact, and long-term costs of various flooring options to make an informed decision.

Concrete floors, while a common initial choice, can suffer from accelerated wear and require frequent maintenance and replacement. High-performance cementitious toppings, such as those made with calcined bauxite or other durable aggregates, provide an alternative that extends the life of floors and reduces the frequency of repairs, all while minimizing environmental impact.

Incorporating sustainable practices in flooring selection, including optimizing concrete mixes and reducing the carbon footprint of materials, will benefit both the environment and the facility’s bottom line. By conducting a thorough analysis of the available options, facility owners can select the flooring system that offers the best balance of durability, sustainability, and cost-effectiveness for their specific needs. | WA

Project Profile: The New York Sanitation North Marine Transfer Station (Flushing, NY)

This New York City Solid Waste transfer station averages 2,500 tons of municipal waste every day. Trucks enter through the upper level then drop the trash from an elevated weigh scale area onto the tipping floor 15 feet below. Loaders then move the trash into a series of compactors where barges haul away the MSW to a landfill. The tipping floor was designed with a 15 in (38 cm) thick structural slab topped with 3 in. (8 cm.) of 6,000 psi non-structural (no rebar) concrete. As the topping wore down to the base slab every few years, it would be replaced. Surface prep, placement, and cure time caused the facility to be taken offline for at least 10 days. New York Sanitation had tried other toppings to get around the long shutdown times with poor results.

In 2018 management installed a 1,000 ft.2 (93 m.2) mock-up using EucoFloor 404 from Euclid Chemical in the highest wear area. After monitoring the topping for six months, the NYC Department of Sanitation told engineering company, HDR, that they wanted EucoFloor 404 everywhere. The floor has been in service since October 2019 and management is well pleased with the results. Infrastructure Repair Services is part of a network of qualified contractors across the U.S. who have the expertise to install a variety of Euclid Chemical products, including EUCOFLOOR 404.

Vincent Beyer is Technical Sales Representative and a Heavy-Duty Flooring Specialist for Euclid Chemical. He has more than 35 years of concrete industry repair and restoration experience and has an extensive background in specialty concrete restoration and development of materials used in extreme high wear environments. Vince has worked in the solid waste and industrial market as a material supplier, contractor, and consultant for more than 30 years. He is a current member of SWANA and focuses on improving the durability of concrete floors used in the Solid Waste Industry. Vince can be reached at [email protected].

Acknowledgements
Design of Waste Transfer Station Concrete Overlays Against Deterioration by Sungwoo Park, Morgan Barlaz, Mohammad Pour-Ghaz (North Carolina State University)
Creating Durable Floors Concrete for Your Solid Waste Facility by Bob Swan (HD Concrete Floors)
Tipping Floors-Making Them Healthy Again by Jim Andrews (American Restore)
Creating a Leachate Resistant Concrete Floor by Bob Swan (HD Concrete Floors)