TDD Trenchless Technology Specialists Pipe Bursting is a method of replacing old pipe with a new pipe of the same or larger diameter. This is achieved by pushing the bursting rods inside the pipe to be renewed utilising an hydraulic bursting unit.   After pushing the rods up inside the main/pipe to be renewed, a splitter and expander are attached, which, when pulled back to the bursting rig, break and push the old main aside to accommodate the new pipe.