Horizontal slip-forming is a method of constructing continuous concrete elements, such as kerbs, drainage channels and safety barriers. It involves the extrusion of the concrete in situ rather than casting it in short lengths. (The principles are the same as for vertical slip-forming, a technique for the rapid construction of tall concrete structures).
It offers the advantages of speed, the ability to produce a monolithic structure, and economy of operation. Construction is by means of a specially designed machine consisting of a mould of the required dimensions and vibrators to compact the concrete. The machine is self-powered and is mounted on wheels or tracks. A stiff concrete mix is used and the machine moves forward at such a rate that the concrete emerging from the rear is self-supporting. Line and level are achieved by the machine following a prefixed guide wire.