Asphalt concrete wearing course details design in AutoCAD 2D drawing, CAD file. The wearing course is the top layer of asphalt construction. It is built to withstand weather, traffic abrasion, and skidding while accommodating the volume of traffic. In comparison to the middle or base courses of asphalt, the aggregate and mineral filler are smaller in size. For more detailed information download the 2D AutoCAD dwg file.