Florida Rock Industries Inc., a mining, ready mixed concrete, and construction products company in Gainesville, Fla., has found an innovative and inexpensive way to reduce the number of complaints from motorists claiming windshield damage from concrete escaping from truck mixer chutes during transit. The solution is a device permanently attached to the lower portion of a truck's flip-over chute. The chute-block consists of a half-round metal plate welded to the lower section of the chute. A piece of used conveyor belting is bolted to the metal plate and trimmed to match the chute's contours. This provides a good seal against both sand and aggregate leakage. The device has no moving parts, requires no operator involvement, and is automatically positioned when the chute is moved to either the folded or unfolded position.