GB1399510A - Artificial and natural structures - Google Patents

Abstract

1399510 Forming or repairing structures by adhesive BALFOUR BEATTY & CO LTD 11 Oct 1973 [11 Oct 1972 I Nov 1972 13 July 1973] 46909/72 50321/72 and 33559/73 Headings E1F and E1S A fissured structure, e.g. a cracked bridge pier or a pile of bricks, is strengthened by sucking a hardenable liquid or semi-liquid material, e.g. a resinous grout or a cement grout, through the structure after evacuating air and any fluid from the structure which is at least partially surrounded by a substantially fluid-tight enclosure, e.g. a flexible shroud or a coating. A brick bridge pier (Fig 3) is repaired using a shroud 15 in combination with a synthetic resin coating 14, the edges of the shroud being sealed against the structure, and the shroud being evacuated using a vacuum pump or air compressor/venturi arrangement. The structure is allowed to stand for, e.g. three hours to allow it to dry out, and then grout is sucked through from the lower pipe shown. The grout may include polyester resin or epoxy resin, and may be reinforced. A brick wall (Fig 4) may be strengthened in a similar way, a dry wall being erected initially, and then impregnated with polyester resin inside a transparent polythene shroud 32. Spacers can be employed between the bricks if desired. If a high viscosity/high surface tension grout is employed, a pulsating vacuum may be employed, e.g. twelve pulsations per minute to achieve fuller impregnation. Alternatively the degree of vacuum may be initially low and increased when impregnation is almost complete to remove air bubbles. An archaeological ruin (Fig 5) comprising stone blocks may be repaired by replacing old blocks with new ones 52 with spacers between, and a wire 53 is employed, through which an electric current is passed, to speed the setting of the grout. The wire is left in as reinforcement. The wire passes through fluid-tight seals on the shroud. Inlet fitting adaptors are illustrated in Fig 6 (not shown here) and Fig 7, the latter incorporating a cutter 76, which is rotated to form a hole in the shroud.