GB2124673A

GB2124673A - Expansion joint

Info

Publication number: GB2124673A
Application number: GB08317852A
Authority: GB
Inventors: Reinhold Huber; Waldemar Koster
Original assignee: Kober AG Glarus; Koerber AG
Current assignee: Kober AG Glarus; Koerber AG
Priority date: 1982-07-07
Filing date: 1983-06-30
Publication date: 1984-02-22
Also published as: ZA834743B; DE3225304A1; DE3225304C2; GB2124673B; GB8317852D0

Abstract

A water-tight expansion joint covering in carriageways comprising an elastomeric element 1 which is embedded, level with the carriageway and on both sides of the joint 2, in edge elements 6 of the carriageway 5. The edge elements are produced at the construction site from elastomeric concrete by filling appropriate recesses in the carriageway in a manner such that they are directly adjacent, both laterally and underneath, to the long edges of the expansion element 1. <IMAGE>

Description

SPECIFICATION Expansion joint covering in carriageways The invention relates to an expansion joint covering in carriageways having an elastomeric expansion element which is embedded in a water-tight manner between edge elements which border the joint on both sides end are produced at the construction site by filling appropriate recesses of the carriageway.

A known expansion joint covering of this type (Swiss Patent Specification 553,291), which is likewise inserted into recesses of the carriageway on both sides of the joint, employs edge elements of resin-based mortar which are cast on site or prefabricated and which are bonded laterally to the carriageway surfacing and downwards to the concrete of the substructure, by means of a suitable joint-sealing compound. The joint is sealed by pressing a permanently elastic preformed joint filler, under compression, between the edge elements, the said joint filler resting on narrow bars projecting from the edge elements below. Although the resin-based concrete edge elements stiffen the edges of the joint, their joint-side edge may still crumble in the course of time.This is caused by severe shocks as a result of the traffic loads, which are not sufficiently damped even though the joint-sealing compound possesses a certain amount of elasticity. Fixing the preformed joint filler appears to present problems; in the case of a wide joint, there is the danger of the filler being pulled out under the suction action of the traffic running over it.

In another known expansion joint covering (German Offenlegungsschrift 22 53 140), the edge elements are formed from resin-based mortar by placing a rubber profile over the joint and filling the remaining space within the recess of the carriageway with resin-based mortar. The danger of the rubber profile becoming detached from the edge elements is reduced in this case by virtue of the fact that the rubber profile possesses, at mid-height, laterally projecting ribs which become thicker towards the ends and are embedded in a closely fitting manner in the edge elements. It is to be expected that the edge of the edge element which is adjacent to the rubber profile will break in the course of time.

In another known expansion joint covering closed on the carriageway side (U.S. Patent Specification 4,279,533), the expansion element and the edge elements consist of polyurethane, the edge element material having a Shore hardness more than twice as high as that of the material of the expansion element. A metal plate which carries the expansion element and is laid over the joint serves to take vertical loads. When a joint covering of this type is driven over, there is a danger of the edge element becoming detached from the laterally adjacent carriageway edge as a result of the pronounced deformation of the edge element under the vertical load.

At the same time, the edges of the carriageway edge break.

Accordingly, it is an object of the present invention to provide an expansion joint covering of the type mentioned at the outset, using an elastomeric expansion element which is firmly connected to the carriageway surface and not only manages without the customary steel edge member but also fits permanently and tightly into the joint edges without requiring expensive shaping, damping of the shocks caused by the traffic loads being achieved at the same time.

This object is achieved, in accordance with the invention, if the edge elements consist of elastomeric concrete and are directly adjacent to the expansion element, both laterally and underneath, and if the expansion element, the edge elements and the carriageway are firmly connected to one another at the level of the carriageway, their adjacent surfaces forming a firm, permanent connection with one another.

In accordance with this concept, the elastomeric expansion element is embedded in an appropriate recess of the edge elements, which - and this is particularly important - in this case consist not of a hard material but of elastomeric concrete. The latter can be bonded, without difficulty, to the surface of the recesses in the joint edges, namely laterally to the carriageway surfacing and below to the reinforced concrete of the carriageway substructure. The edge elements of elastomeric concrete also constitute an ideal transition between the relatively hard carriageway surfacing and the elastomeric expansion element. Such a gradation of materials ensures a permanent and reliable connection between the three stated constructional components.In particular, the chosen gradation of materials prevents breaking of the edges of the constructional components in the region of the carriageway surface.

As already indicated, correct matching of the materials used for the expansion element, the edge elements and the carriageway is an essential feature of the present invention. As an orientation point in this respect, it is advantageous if the modulus of elasticity of the edge elements is about ten times the modulus of elasticity of the expansion element.

Where the carriageway surfacing is of bitumen concrete, there is a further step involving a power of ten, in that the modulus of elasticity of the bitumen concrete is about ten times the modulus of elasticity of the edge element.

In this manner, and in accordance with the invention, a stepwise transition in respect of the stiffness of the materials is achieved, on the one hand in the horizontal direction, and on the other hand in the vertical direction, between the necessarily soft expansion element and the bitumen concrete or the structural concrete directly below the carriageway surfacing. A very important factor with regard to this transition is the choice of the edge element material, namely elastomeric concrete.

In a gradation of stiffnesses which are suitable in practice, expressed as rough approximations of the modulus of elasticity (N/mm2), the value for the expansion element is 40 N/mm2, and this increases in each case by a factor of 10 for the elastomeric concrete (400 N/mm2), the bitumen concrete (4000 N/mm2) and the reinforced concrete or structural concrete (40,000 N/mm2).

The coefficients of expansion of these materials bear an inverse relation to one another, i.e. the smaller the modulus of elasticity the higher the expansion, and the gradation in respect of expansibility can also be expressed approximately in terms of powers of 10.

A suitable material for the expansion element is polyurethane which cures at low temperatures; this elastomer can also form the elastomeric component of the elastomeric concrete from which the edge elements are made, this component being accompanied by an additive which generally consists of mineral particles, such as gravel or sand.

For purposes of illustration only, it should be pointed out that bitumen concrete consists of an additive of this type together with bitumen, while the reinforced concrete of the substructure consists of an additive of this type together with cement.

Particularly when the same elastomeric basis is used, firm bonds which in every way are capable of taking the stresses produced by traffic loads can be achieved between the expansion element and the edge elemDnts on -he on~ hand, and between the edge elements and the edges of the recesses in the carriageway on the other hand.

The expansion element lies firmly bonded in a bed of elastomeric concrete in the form of the edge elements, the sea; achieved being water-tight in all states of motion of the ,.oint.

The edge elements of elastomeric concrete constitute resilient edge members which possess limited deformability and a, a highly shock-absorbent. They are sufficiently rigid to constitute ideal s'pports for the bitumen concrete which is susceptible to breakage, on the one hand, and me soft expansion element on the other hand, i.e, they provide support on both sides; however, on @@@ lower face, they also form a permare !onct to tG the reinforced concrete.As a result of the simiiar deformation behaviour of the edge elements with respect to the bitumen concrete of the carriageway edge on the one hand and with respect to the elastomeric expansion element on the other hand, detachment of materials in the connecting region can be avoided.

The result is an expansion joint transition which is completely level with the carriageway and which, in addition, enables an exact fitting to the carriageway surface through on-site production. While the edge elements are always cast at the construction site, the expansion element can be prefabricated and inserted into the recesses of the still slightly gel-like edge elements, or may likewise be first cast at the construction site.

An embodiment of the invention is described below with reference to the drawing.

An elastomeric expansion element 1, preferably of polyurethane, bridges over the joint 2 between a ieft-hand reinforced @@@@@@@ slat 3 and a right-hand reinforced concrete slab 4 of a carriageway. A bitumen concrete carriageway surfacing 5, which has a secrion cut out -along the joint 2, is laid on top of these reinforced concrete s@abs 3 and 4. The recess defined by the cu@@@@ section is cleaned, the prefabricated expansion e,er!.ent 1 is positioned and the recess is filled with elastomeric concrete, so that edge elements 6 are formed. The edge elements 6 support the expansion element 1 both horizontally and from below. They form an unbreakable bond to the expansion element 1 on the one hand and, on the other hand, to the boundary surface 7 of the carriageway surfacing and to the boundary surface 8 of the reinforced substructure.

In a particularly advantageous embodiment, the expansion element 1 can also be cast at the construction site. In this case, the elastomeric concrete edge elements are first cast so that they have a cut-out edge. Thereafter, the joint gap is closed with a filler, and the expansion element is then cast from an elastomer which cures at low temperatures, the cut-out sections of the edge-eiements 6 being filled.

Claims

1. Expansion joint covering in carriageways having an elastomeric expansion element (1) which is embedded in a water-tight manner between edge elements (6) which border the joint on both sides and are produced at the construction site by filling appropriate recesses of the carriageway (5), characterised in that the edge elements (6) consist of elastomeric concrete and are directly adjacent to the expansion element (1), both laterally and underneath, and that the expansion element, the edge elements and the carriageway are firmly connected to one another at the level of the carriageway, their adjacent surfaces forming a firm, permanent connection with one another.

2. Expansion joint covering according to Claim 1, characterised in that the elastomeric component of the elastomeric concrete from which the edge elements (6) are made corresponds to the elastomer of the expansion element (1).

3. Expansion joint covering according to Claim 2, characterised in that the elastomeric concrete of the edge elements (6) is produced by adding mineral particles to the elastomer of the expansion element (1).

4. Expansion joint covering according to one of Claims 1 to 3, characterised in that the expansion element (1), too, is produced by casting it, at the constrution site, between cut-out sections of the edge elements (6).

5. Expansion joint covering according to one of Claims 1 to 4, characterised in that the elastomer of the expansion element (1) is polyurethane which cures at low temperatures.

6. An expansion joint covering substantially as hereinbefore described with reference to and as illustrated in the accompanying drawing.