Segment
There is a method called ‘cutter head’ for laying pipe in the ground. This is a method where the excavated wall surface, after being excavated by rotating blades on the tip of a cutter head, is assembled with factory produced pipe pieces. These pipe pieces are called segments and they are made of either concrete or metal. These segments are widely used as covering material primarily for mid to large tunnel openings, and with roads, subways, public utility ducts, water and sewerage ways, power and communication networks. Anti-bacterial concrete is also commonly used for segments.