You can cool concrete by building it with imbedded cooling lines (water or other cooled liquids running through pipes). This has been done in a number of zoo/aquarium settings. Don't know if Detroit's bear exhibits include such a feature, but it is possible. Unlikely that all of the extensive concrete "decks" in these exhibits are treated this way, as it would have been extremely expensive to build and to operate.
Obviously the heat retention of dark-colored concrete is greater than with the white "ice floes" seen here. Don't know if reflected light would be a problem for an animal adapted to live on ice in the bright sun for many months at a time. Not good for tapirs; probably not an issue for polar bears.
Obviously the heat retention of dark-colored concrete is greater than with the white "ice floes" seen here. Don't know if reflected light would be a problem for an animal adapted to live on ice in the bright sun for many months at a time. Not good for tapirs; probably not an issue for polar bears.