A process for the production of a concrete structure after the Gleitschaltungsmethode

In a method of providing a concrete structure by the slip forming method, there is added to the concrete prior to its use in the slip forming process a water-reducing agent and at least one of a water-soluble natural polysaccharide and a water-soluble acrylic polymer, the proportion by weight of water-reducing agent to polysaccharide and/or polymer being from 90 : 10 - 99.9 : 0.1. The concrete has a thixotropic structure which allows it to flow when flow is necessary and stiffen when stiffness is necessary. Slip formed concrete made by this method has relatively little aeration.