2014 Education (New Construction) Winner

The Charles County Public Schools system in Maryland was interested in installing polished concrete floors in future schools, so as a test opted for placing and polishing concrete in the cafeteria of the new St. Charles High School. The cafeteria is a high-profile area that’s also part of the school's main entrance.

The architect and owner chose a seeded aggregate installation to provide a terrazzo-like finish at a lower cost than actual terrazzo. This eliminated the need to manufacture and transport materials to the jobsite by utilizing the concrete placed as part of construction.

Polished concrete contractor Cuviello Concrete of Stevensville, Md., worked with the architect and general contractor to produce a substrate that would be the most conducive to the polishing processes. This included mix design, finishing methods, curing methods, joint placement, and final protection.

They also collaborated to design a seeded, glass-exposed finish that includes decorative saw-cut joints filled with polyurea and two different shades of black dye. They used recycled glass bottles instead of virgin glass.

Approximately 678,300 pounds of locally sourced specialty aggregate was mixed into the concrete, and 1/8- to 1/4-inch recycled glass was hand-seeded into the surface—consisting of 2400 pounds of red, purple, and orange glass and 5000 pounds of blue glass.

The polishing team consisted of 12 craftsmen, including a foreman and an assistant foreman. Three craftsmen finished edges to match the main body of the floor to the finished block and architectural concrete seating risers, creating a virtually seamless look with no distinguishable differences.

Polishing past refinement
The project was priced to allow for additional time to fully refine the cafeteria’s surface to its “past maximum refinement”—the maximum durability that the surface would allow as part of the Green Endurance Flooring manufacturing processes. The process was done wet up to 200-grit resin to ensure silica dust was contained and to allow for the abrasives to refine past maximum refinement.

When the process was complete, the floor was covered with an 18-mil, felt-backed poly made especially for Cuviello Concrete’s polished projects. The protection can withstand heavy construction; lifts and job boxes can be rolled over and stored on top.

Environmental concerns were handled through dumpster filters, which captured the cement fines and allowed clean, pH-balanced water to drain. This greatly reduced slurry disposal costs.

It’s all about teamwork
The project was successful because the general contractor took time to understand the installation, and all players—including the architect, owner, ready-mix producer, placing/finishing contractor—worked together to ensure a successful installation. The general contractor also embraced the time requirements, ensured flooring was free and clear of obstacles, and enforced working rules upon the other trades.

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