The pilot reported that, during final approach to land, he noticed a road grader operating on the far end of the runway. He made a radio transmission stating that the flight was 4 miles out on final approach and observed the road grader pull over at the opposite end of the airport and park. Believing that the operator of the road grader heard his call and parked, he proceeded with a normal approach and landing. After touchdown, he applied reverse with moderate braking. When the airplane was fully out of reverse and had slowed to about 35 mph, he noticed a large piece of foreign object debris (FOD) on the runway centerline. The FOD appeared to be about 18 inches wide and about 12 inches tall. He veered to the left in an effort to straddle the FOD with main landing gear. Subsequently, the right main landing gear struck the FOD, the right main landing gear collapsed, and the airplane slid about 75 ft down the runway centerline before coming to a stop. The airplane sustained substantial damage to the right wing. A postaccident inspection revealed that the FOD was a chunk of ice. The pilot also learned that the road grader was not equipped with an aircraft radio. The pilot reported no preaccident mechanical failures or malfunctions with the airplane that would have precluded normal operation. The Federal Aviation Administration Supplement Alaska for the applicable airport under AIRPORT REMARKS states in part: Unattended. Rwy condition not monitored, recommend visual inspection prior to using. Seabirds on and invof arpt. Vehicle and pedestrians frequently use numerous roads and trails that cross rwy. Loose rocks on rwy sfc up to 6". Rwy 04–22 sfc contains numerous rocks and puddles. Several roads and trails cross Rwy 04–22. Rwy 04 thlds marked with orange reflective cones.