Abstract: The joint comprises a pair (12, 14) of complementary engineering grade polymer injection moldings. Each molding is comprised of generally equal length oblique webs (15), set at 60° to a mid-plane (16) of the assembled joint, shorter, inner webs (17) and a longer, outer webs (18). Centrally of each outer web (18) is an aperture (21) and centrally of each inner web is a pin (22) with a step (23) and a pointed head (24). The heads of one molding clip into the apertures of the other while the steps determine their separation gap (25). The trapezium wave shape of the joint provides re-entrants (31) from the plane of the outer webs (18) towards that of the inner webs. Outwards of the re-entrants extend anchoring formations (33). Behind each re-entrant these formations are joined by a tab (34).

Abstract: A free movement, arris protection, construction joint has a pair of arris protection members formed complementarily from strips of sheet with a continuous trapezium wave form. A divider one of the members is typically 100 mm deep for a nominal 0.1 m deep slab. The other one is typically 50 mm deep. The members are of steel plate. The wave form is comprised of flanges extending in the length of the joint and of webs angled to the flanges and the length of the joint. The flanges are spaced on opposite sides of a mid-plane of the joint. The members are bolted together with flangible nylon bolts, with their top (in use) edges flush. Welded to the outer ones of the flanges are L strips having apertures in their flats extending from the flanges for anchoring the joint to its slabs.

Abstract: An anti-spalling edging comprising: a metal strip 21,31 adapted for concrete to be cast against, a return 22,32 along a top edge of the strip and forming a corner with the metal strip, a down-turn 23,33 from the edge of the return spaced from the strip and cut-outs in 26,36 the down-turn for anchoring it in the concrete and an elongate metallic member 201,202 extending in the corner, fixed to the strip and the return for reinforcement of the anti-spalling edge at the corner.

Abstract: An anti-spalling edging comprising: a metal strip 21,31 adapted for concrete to be cast against, a return 22,32 along a top edge of the strip and forming a corner with the metal strip, a down-turn 23,33 from the edge of the return spaced from the strip and cut-outs in 26,36 the down-turn for anchoring it in the concrete and an elongate metallic member 201,202 extending in the corner, fixed to the strip and the return for reinforcement of the anti-spalling edge at the corner.

Abstract: A screed rail comprises first and second elongate plate members arranged in face-to-face configuration, the first plate member being attached to leg members by height-adjustable lock means and the second plate member being attached to the first plate member by frangible joining means with the upper edges of the plate members in registration. The second plate member is attached only to the first plate member and the first plate member is attached to the leg members and by independent frangible connections to the second plate member whereby the plate members can separate laterally as the concrete cures without the attachment of the leg members inhibiting movement of the second plate member relative to the first.