GB1067671A - Building blocks, slabs and like products moulded from concrete or the like - Google Patents

Abstract

1,067,671. Moulding blocks, slabs, pillars, pipes &c. NATIONAL RESEARCH DEVELOPMENT CORPORATION. Jan. 2, 1964 [Oct. 4, 1962], No. 21497/62. Heading B5A. [Also in Division E1] Concrete articles are made by introducing a mixture of powdered and/or granular materials and cement an a dry state into a mould having perforations, causing water to pass through the mould perforations by capillary attraction within the material itself and in sufficient quantity only to put the mixture into a state of capillary cohesion without excess of water and allowing the mixture to set. In the embodiment shown dry concrete mixture 5 is permeated with water by inverting a plastic mould 1, on to which a lid 4 has been pressed, into a trough 6 of water. The block may be left in the mould to set or it may be removed once the material is permeated with water, in which condition it can be handled. In further embodiments, pillars, tubes, channel linings and road surfaces are produced by introducing dry mixture ;into .moulds of the appropriate configuration provided with troughs which contain sufficient water to permeate the mixture. Examples are given of moulds of thin flexible sheet material, e.g. polyethylene, in the form of tubes which when filled with dry mixture and sealed at their ends are placed in a bath of water which permeates them. The tube is perforated before or after the introduction of dry concrete mixture The cross-section of the mixture when set may be varied by placing the tube in a supporting mould or by pressing it between parallel plates (25, 26), Fig. 15 (not shown. By means of an adhesive a covering can be affixed to the flexible moulds while the mixture is setting. The moulded articles produced in flexible moulds may be reinforced or secured together by fixing strips having spikes which penetrate into the moulding before the mixture has set, Fig. 19 (not shown). The construction of a catenary roof, Fig. 28 (not shown), is described in which a series of flexible filled moulds (50), Fig. 29 (not shown), having reinforcing wires (53) are secured together with pins (54) and sealed together with sealant (55). The moulds are initially unperforated and to set the mixture they are perforated, e.g. with a spiked roller, and water sprayed over them. Blocks, slabs or the interior of pipes may be provided with a smooth resin surface by bonding thereto a thermosetting resin. In one embodiment, Fig. 30 (not shown), dry mixture (59) is poured into a mould (56) having a flexible plate (57) coated with liquid resin on its base. The resin soaks partially into the bottom portion of the dry mixture and when the resin has set the mould is permeated with water as previously described to produce a rigid article.