Abstract: A rock-dowel has a dowel shank and a threaded end at the head or proximal end of the dowel. Three groups of projecting mixing vanes are spaced along the shank. In use when inserted into a pre-drilled hole containing a two-part encapsulating resin and spun, the rock-dowel can thoroughly mix the two part resin encapsulating resin and force the resin casings into the back of the pre-drilled hole. Also disclosed is a nut made from a plastics material defining a first, typically relatively wider, barrel portion and a second, typically relatively narrower, nut portion, the second portion defining a nut section for engagement with a socket, wherein an area of weakness is provided between the first and second portions such that the second portion breaks from the first portion when a particular torque value is applied to the nut.

Abstract: A fibre reinforced rock dowel (10) for use in reinforcing strata or the like has a generally cylindrical shank (12) having a longitudinal axis and defines one or more groups of mixing vanes (16, 18, 20) projecting from the shank, and a threaded end (14) for the attachment of a nut (13). The dowel is reinforced by inner (21a) and outer (21b) filaments extending generally along the longitudinal axis. At least the outer filaments extend in a generally helical path through the dowel with outer filaments extending in a helical path in the opposite sense to the thread of the threaded end. The dowel is manufactured by a process in which continuous fibre filaments (7) are drawn through a resin filled bath (6) into a press (4) with fixed lower and movable upper heated dies so that when the press closes it moulds the shape of the dowel, in a process known as pulforming”, with the cured dowel attached to the filaments being rotated about its longitudinal axis to impart twist to the fibres in the dies (4a, 4b).

Abstract: A rock-dowel has a dowel shank has a diameter of about 20-22 mm, and a threaded end at the head or proximal end of the dowel. Three groups of projecting mixing vanes are spaced along the shank. A first group of vanes at the tip project at least 2.5 mm and preferably no more than 4 mm from the shank. The second group of vanes which project from the shank by a lesser degree than the first group, are defined in a central portion of the shank spaced from the first group. The third group of vanes which project from the shank by a lesser degree than the second group, are defined adjacent the threaded portion of the shank spaced from the second group. In use when inserted into a pre-drilled hole containing a two-part encapsulating resin and spun, the rock-dowel can thoroughly mix the two part resin encapsulating resin and force the resin casings into the back of the pre-drilled hole.

Abstract: A prefabricated reinforced concrete wall structure formed in two parts, the first part including a plurality of walling units spaced apart but in groups over the whole area of the wall, channel shaped spaces between and around the groups of walling elements being configured in a grid formation and being filled by a high strength reinforced concrete cast in and around the group of walling units and constituting a concrete grid as the dominant structural member of the prefabricated wall panel. The walling units and the concrete grid are further supported by a layer of Portland cement based render on both sides of the wall surface, the completed wall structure being significantly lighter in weight and having a lower Portland cement volume in comparison with normal concrete walls of similar structural ability.