Use different grades of asphalt to lay the asphalt layers of a road. Lay an asphalt base layer with low bitumen content to provide a stable surface, a binder layer with intermediate bitumen content, and a surface layer containing the highest grade material with the highest bitumen content to withstand the stresses of road transport. Tend a paver to lay the asphalt or use different techniques and instruments.
Data Source: Unified Global Standards (ISCED, ISCO, O*NET, ESCO)