Prior to the flight, the pilot obtained a weather briefing and there were no reports of icing along the intended route of flight. The experimental airplane was equipped with a de-ice system, and during the preflight inspection, the system was operational and continued to be operational during the flight. Prior to entering icing conditions, the de-ice system indicated a "failure" to the pilot; however, he was not concerned because he was in the clouds and the airframe was not accumulating any ice. Shortly thereafter during the descent, the airplane accumulated approximately 6 to 10 millimeters of rime ice. The pilot reported the ice to air traffic control and they cleared him to a lower altitude. Because of the ice on the airplane, the pilot "maintained a higher than usual airspeed in the pattern and on final [approach]." While over the runway 27 (asphalt; 3,549 feet long by 60 feet wide) threshold, the pilot "experienced an abrupt counter-clockwise roll...there was no opportunity for recovery." The left main landing gear contacted the runway and collapsed. The airplane turned to the left and came to rest upright on the runway surface. The pilot estimated the winds were from 350 degrees at 10 knots. Examination of the airplane revealed the left wing sustained substantial damage. Other than the de-ice system, the pilot reported no additional anomalies with the airplane. The reason for the de-ice system failure was not determined.