Joints for concrete slabs, and joint supports

Abstract

A prefabricated expansion joint for a concrete slab, the joint comprising a hollow extrusion of plastics material having an enlarged base portion for connecting directly or indirectly to a surface on which a concrete slab is to be made, a top portion for coming flush with the surface of the concrete slab that is to be made, and an intermediate portion with two side walls extending between the base portion and the top portion. The top portion comprises a strip of flexible plastics material in which there extends a central web of relatively rigid plastics material connected via its bottom edge to the side walls of the joint, forming a single part together therewith and extending vertically over at least the major fraction of the height of the top portion of the joint.

Description

BACKGROUND OF THE INVENTION [0001] The invention relates to making expansion or bay joints for concrete slabs, and more particularly to hollow bars or sections of plastics material for constituting such joints and to accessories enabling them to be put into place on a surface on which a concrete slab is to be cast. [0002] Hollow plastics material sections that are put into place on a surface prior to casting a slab and that subsequently remain permanently therein so as to constitute joints are well known. Such sections also be used for making it easier to level the slab while it is being formed, by placing the sections at a height that corresponds to the thickness desired for the slab. Reference can be made to patent documents FR 2 292 907, EP 0 053 977, and EP 0 152 367. [0003] At their tops, those prior art sections present a narrow width, and as a result gaps can form in the surface of the slab between the joint and the two adjacent portions of the slab, due to the dimensions of ...

AI Technical Summary

Benefits of technology

[0006] Thus, the presence of a strip of flexible plastics material at the top of the joint makes it possible to guarantee that sealing is maintained between the joint and the adjacent portions of the slab while nevertheless conserving sufficient mechanical strength by virtue of the relatively rigid central web.

[0007] Advantageously, the strip of flexible plastics material is coextruded with the remainder of the joint that is made of a relatively rigid plastics material, thereby enabling the joint to be manufactured in a single operation.

[0008] Also advantageously, the web of the top portion has a top edge that is set back from the top face of the strip of flexible plastics material. Thus, the top edge of the joint that becomes flush with the surface of the slab, presents a uniform surface state giving the slab a generally clean appearance. In addition, this gives the top of the joint a certain amount of flexibility in the vertical direction.

[0010] In another variant embodiment, the strip of flexible plastics material is disposed between two side walls of relatively rigid plastics material each extending over at least a fraction of the height of the top portion, in register with the side walls of the joint, thereby reinforcing the sides of the top of the joint. The side walls on either side of the strip of flexible plastics material preferably present splines or external portions in relief serving to provide good bonding with the concrete.

Problems solved by technology

At their tops, those prior art sections present a narrow width, and as a result gaps can form in the surface of the slab between the joint and the two adjacent portions of the slab, due to the dimensions of the concrete varying.

In addition to this causing the joint to take on an appearance that can be unattractive, the presence of such a gap or clearance facilitates the insertion or penetration of water or other liquids or solids.

That operation is time consuming and must be performed long enough in advance to allow the mortar to set before the slab is cast.

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