GB1342906A - Concrete elements and the production thereof - Google Patents

Abstract

1342906 Beams CONCRETE Ltd 19 April 1971 [11 Sept 1970] 43532/70 Heading E1W [Also in Division B5] Concrete elements, such as beams or slabs are cast around a foamed core in a flexible wrapping. Several groups or cores may be laid on a wet concrete base in parallel arrays set end-to-end (Fig. 4, not shown) with prestressed reinforcing wires laid between cores and shuttering to divide up the groups further concrete being poured over the cores to form slabs having a plurality of parallel foam core inserts embedded therein the wires between groups being subsequently severed. Structures or foundations may be cast in situ. The preferred foam is urea-formaldehyde but it may e.g. be phenol-formaldehyde, polyurethane or polystyrene. An arrangement for mixing the foam and supplying it to foam gun is described. The preferred wrapping is a lay flat tubular polyethylene membrane 2, Fig. 2 which is slipped over a carrier 1 concertina fashion, the end being affixed to a bracket 8 which is fastened to a moving chain 9. Foam is supplied to the interior of the polyethylene tube through a nozzle 3, the foam-filled tube being shaped by a die 4, which may be of wood faced internally with polytetrafluoroethylene, as it is drawn therethrough. In a variation the foam-filled tube is fed between moving belts to a severing device the position of which is controlled by a sensing element so that the cores may be cut to various lengths. Alternatively cores may be moulded in individual moulds.