In October 2018, sportswear company Descente Korea Ltd. opened a research and development center in South Korea with plans to launch a new brand of running shoes in time for the 2020 Tokyo Olympics and Paralympics. The expansive Descente Innovation Studio Complex includes a design studio and research, material and product labs along with a 400-meter running track, a futsal pitch and a basketball court to test the performance of athletic shoes.
The project owner wanted the building’s walls and floors to look like exposed concrete. Contractor CJ E&C of Seoul, South Korea, was tasked with installing 40,000 square feet of polished concrete overlay in the entrance and lobby, which includes a corridor, circular staircase and stairway. The contractor used CTS Cement’s Rapid Set® Skim Coat and TRU® Self-Leveling polishable topping due to the products’ quick cure times and the ability to achieve high luster and outstanding clarity with TRU.
Skim Coat is a smooth, sand-free, hydraulic cement-based material that is used as an underlayment to level and smooth cement or concrete substrates. For this project, the contractor blended the TRU Self-Leveling topping to create a smooth surface. Gray pigment was added to match the flooring to the walls.
Although the facility was new construction, it was built on reclaimed land (the area was originally a mudflat near the sea), which resulted in several cracks in the substrate. The contractor addressed the cracks by first sawcutting them and then filling them with a repair material. Next, the topping was applied at 3/8 inch by gauge rake and finished with a spiked roller to release any trapped air.
The crew was able to grind and polish 24 hours after the overlay was placed, starting with 60-grit metal-bonded diamond abrasives and moving up to 30- and 50-grit ceramic abrasives for honing and then to 50-, 100- and 200-grit resin abrasives before applying a densifer. The crew then polished to 800 grit. To protect the surface, they applied a guard and penetrating sealer.
For the vertical portions of the stairway and spiral staircase, the contractor built forms and filled them with TRU. This helped produce a seamless transition between the flooring and staircases, in both color and texture Work took place June 1 through Oct. 1, 2018. The customer was very satisfied with the results.
