A CRJ-700 taxied onto a ramp with NIL braking and used maximum reverse to stop the aircraft from colliding with another aircraft. Airport authorities treated the ramp before the aircraft could taxi to the gate.

Narrative

As I was taxiing aircraft onto the ramp at a very slow speed; the aircraft started to slide uncontrollably. Directly in front of us was a parked B717. I had fully depressed both brake pedals with no response. I immediately deployed both thrust reversers to full power. The aircraft turned 90 degrees to the left and stopped just 20 ft shy of the parked B717. Once the aircraft came to a stop; I set the parking brake and called the Tower to let them know what had just occurred. They dispatched a dump truck full of sand; and sanded all around the aircraft. The dump truck then led me into the gate; with no other problems. Weather conditions and poor planning on the city's part for not having the ramp in a safe condition for aircraft to be able to taxi. Lights that are also on the ramp cause a glare to where we had a hard time noticing there was ice present. The city should have put chemicals or sand on the ramp. We ran the flight on time. They knew we were coming and a previous aircraft reported to the Tower the ramp and taxiway braking was less than good. It was nil 30 minutes later when we arrived.