A stretch of six-lane road experimentally paved with slag from steel-making in India has been shown to weather the beating from thousands of heavy trucks even though the surface is 30% shallower than that of roads paved with natural aggregates. Slag is made up of impurities melted out of the ore during the steel-making process. The trial, guided by the Central Road Research Institute (CSIR-CRRI) and sponsored by ArcelorMittal Nippon Steel (AM/NS).