Bridging material for a joint construction as well as prefabricated bridging unit

Abstract

 Bridging material for a joint in a road, such as a joint at the location of an abutment and a bridge deck, which bridging material is intended to be laid with a base course on the sections enclosing the joint, and the top of which bridging material is intended for applying thereon a wearing course of asphaltic concrete, comprising a bottom layer that defines a lower surface, a top layer that defines a top surface and a series of strips of a relatively hard material arranged alongside one another, which series of strips is accommodated between the two layers and which strips are intended to be laid transversely over the joint.

Description

[0001] The invention relates to a bridging material that is used in a seamless joint construction at the location of a transition in a pavement between, for example, an abutment and a bridge deck. According to a known embodiment a steel, strip-shaped plate is placed over the joint for this purpose. An asphaltic concrete is then laid without interruption over the steel plate and the adjoining surfaces of the abutment and the bridge deck. The steel plate supports the asphaltic concrete at the location of the joint, as a result of which deformation of the asphaltic concrete under the influence of road traffic should be prevented.

[0002] Since the road must be able to absorb the differences in expansion between abutment and bridge deck, according to another embodiment the asphaltic concrete is frequently replaced at the location of the joint transition by a mixture of stone chippings and modified bitumen. Such a material is sufficiently flexible to be able to absorb the differences in expansion.

[0003] The advantage of such a seamless transition of the pavement at the location of the joint is that there is no additional noise nuisance. In the case of the traditional joint constructions there is a rubber section between the pavement sections, which gives rise to impact loading by the wheels of the road traffic. A further advantage of the seamless transition is that it is more comfortable for the traffic passing over it.

[0004] Nevertheless, a seamless joint transition is also found to have disadvantages. Specifically, at relatively high temperature and high traffic loads the flexible mixture of stone chippings and bitumen can also start to deform in the vertical direction, as a result of which ruts are formed and the noise production increases. This formation of ruts also continues in the adjoining pavement sections, as a result of which the damage becomes even greater.

[0005] FR-A 2 442 299 discloses a bridging material for a joint in a pavement, such as a joint at the location of an abutment and a bridge deck, which bridging material is intended to be laid with a base course on the sections enclosing the joint, and the top of which bridging material is intended for applying thereon a continuous wearing course of wearing course material, comprising at least a continuous layer of material as well as a series of strips of a relatively hard material which are arranged alongside one another and are intended to be laid transversely over the joint and each have two opposing ends, the one series of ends of which series of strips can be placed on one of the sections enclosing the joint and the other series of ends can be placed on the other section thereof.

[0006] The strips which bridge the joint provide a support for the wearing course. The rubber bearing layer in which the strips are accommodated provides the bridging material with such flexibility that movements at the location of the joint as a consequence of contraction and expansion can be absorbed.

[0007] Nevertheless, this known bridging material as well has the disadvantage that concentrated strains can still arise in the pavement. The identically positioned strips are not readily able to distribute the movements over a wider area in the pavement.

[0008] The aim of the invention is to provide a bridging material with which a seamless joint transition can be produced without this resulting in the said disadvantages arising. Said aim is achieved in that at least two ends of at least one series of ends of the series of strips are offset with respect to a line running transversely to the strips.

[0009] The asphaltic concrete can be firmly supported by means of the bridging material according to the invention. The strain or shock that is generated by mutual movements on either side of the joint is better distributed horizontally over the relatively broad area in which the ends of the strips are located, such that cracking can be largely prevented.

[0010] The spread in the position where the ends of the strips are located can be obtained in various ways. According to a first possibility the strips are offset with respect to one another in their longitudinal direction. With this arrangement the strips can be of the same or different lengths.

[0011] According to a second possibility the strips are symmetrical with respect to a common line of symmetry and at least two strips are of unequal length.

[0012] The layer of material and the series of strips are preferably joined to one another in the form of a coherent bridging unit. In connection with the ease of handling thereof, such a unit can have a restricted size. By laying several units alongside one another over the joint the latter can be completely covered.

[0013] Preferably, the layer of material comprises a bottom layer (adhesive layer) consisting of an adhesive bitumen which improves the attachment to the sections enclosing the joint. The top layer is preferably a membrane, such as a geomembrane (bearing layer).

[0014] Preferably, the strips of hard material are offset in the longitudinal direction with respect to one another in accordance with a specific pattern. In particular, the ends of at least two strips located on one side of the joint can be unequal distances away from said joint. The purpose of these strips is to transmit the movements that are concentrated at the location of the joint below the bridging material a certain distance away from the joint. Because the strips are offset with respect to one another in the longitudinal direction and are not fixed to the sections, these movements are transmitted in varying degrees to the one side and to the other side of the joint.

[0015] Moreover, as a consequence of the fact that the ends of the strips are not in one straight line, the formation of a crack in the wearing course present on top of the bridging material is retarded. After all, in the longitudinal direction of the joint the movement is alternately transmitted to different sides and upwards to the wearing course over a different distance from the joint. This prevents the formation of a straight crack and ensures that the asphaltic concrete is subjected to more uniform strain in the zone in which the ends of the strips are located.

[0016] As a result of the specific strain characteristics, the top layer (bearing layer) of the bridging material provides a further distribution of the movement to the wearing course located above it. Any peak stresses at the location of the ends of the hard strips are prevented by this means.

[0017] According to a first variant, the bridging material can be supported by a steel plate. This steel plate bridges the joint between, for example, the abutment and the bridge deck in a known manner (Fig. 4). According to a second variant the joint is covered by a steel plate with a layer of non-porous asphalt on top of this, over which the bridging material extends (Fig. 3). The secondary joint in the non-porous asphalt is then offset with respect to the joint between abutment and bridge deck. In this case the bridging material lies directly on the non-porous asphalt and the joint contained therein.

[0018] The invention also relates to a joint construction, for example at the location of the transition between an abutment and a bridge deck, comprising two sections enclosing a joint, a bridging material that bridges the joint and bears on both sections, as well as a wearing course that extends continuously over the sections and the bridging material, the bridging material comprising a series of strips made of a relatively hard material arranged alongside one another in the direction of the joint.

[0019] According to the invention provision is made that the ends of at least two strips located on one side of the joint are at unequal distances from said joint.

[0020] The invention will be explained in more detail below with reference to a few illustrative embodiments shown in the figures.

Fig.

1 shows a plan view of a bridging element according to the invention.

Fig. 2

shows a side view in section.

Fig. 3

shows a first possible application of a bridging element in a joint construction.

Fig. 4

shows a second possible application.

Fig. 5

shows a joint construction using a prefabricated bridging unit.

Fig. 6

shows a bridging unit according to the invention in plan view.

Fig. 7

shows the bridging unit in section.

[0021] The bridging element shown in Figs 1 and 2, which consists of the bridging material according to the invention, comprises a bottom bitumen layer 1 or adhesive layer, a top non-woven geomembrane 2 or bearing layer, and a series of strips 3 that are parallel to one another and are offset with respect to one another. These strips 3, which, for example, can consist of hard plastic, are accommodated between the bitumen layer 1 and the membrane layer 2, which latter layers are also attached to one another. As a result the bridging element 4 has good cohesion and it can be handled in a fairly simple manner. In practice several bridging elements 4 are laid alongside one another over a joint, which is bridged by the series of strips 3.

[0022] Two possible applications of the bridging element 4 according to the invention are shown in Figs 3 and 4. In both illustrative embodiments an abutment 5 is shown on which a buffer plate 6 and a bridge deck 7 are supported, the latter by means of a sliding bearing 8.

[0023] Between the bridge deck 7 and the abutment 5 there is a joint 9, over which a steel plate 10 extends that is fixed on one side, for example to the bridge deck 7, by means of a fixing 11 and that is movably supported by means of a sliding bearing 12, for example on the abutment 5.

[0024] In the embodiment in Fig. 3 a layer of non-porous asphalt 13, 14 has been laid over the buffer plate 6, the abutment 5 and the bridge deck 7, in which layer there is a secondary joint 15. The layer of non-porous asphalt 13 extends over the bridge deck 7, over the joint 9 and over part of the abutment 5.

[0025] A number of bridging elements 4 sufficient to cover the entire joint have been laid alongside one another over the secondary joint 15. To provide good adhesion the bottom (bitumen) layer has been omitted over a relatively narrow strip at the ends of the bridging elements 4. The one end of the protruding part of the geomembrane 2 of each bridging element 4 has been attached to the layer of non-porous asphalt 13 by means of a two-component adhesive; in a corresponding manner the other end of the geomembrane 2 has been attached to the other layer of non-porous asphalt 14. Furthermore, the bitumen layer 1 has been stuck in its entirety to the layer of non-porous asphalt 13, 14 (sliding bond). A continuous layer of porous asphalt 16 is then laid over the surface, which is now non-porous, formed by the layers of asphaltic concrete 13, 14 and the bridging elements 4. At the location of the region 17 under which the bridging elements 4 extend an elastic plastic fill is introduced into the voids in the porous asphalt. This is preferably effected immediately after compacting the latter, whilst the asphalt mixture is still warm. The heat in the stone matrix of the porous asphalt ensures that the viscosity of the two-component composition, from which the plastic fill is produced, decreases in the first instance. As a result the voids are filled in an optimum manner and a finely branched elastic matrix is produced.

[0026] The relatively high temperature of the asphalt mixture promotes the two-component reaction. As soon as the porous asphalt has cooled, the plastic has also cured and the wearing course is ready for use after only a few hours. Incidentally, this elastic plastic fill can also be omitted, so that only the ordinary asphalt wearing course 16 continues over the bridging elements.

[0027] In the illustrative embodiment in Fig. 4 a layer of non-porous asphalt 18 has initially been laid on a similar base consisting of buffer plate 6, abutment 5 and bridge deck 7. This layer of non-porous asphalt is then removed on either side of the joint, after which a steel plate 10 is placed over the surfaces of buffer plate 6, abutment 5 and bridge deck 7 that have thus been exposed. A number of bridging elements 4 according to the invention are then placed in position, after which a mixture of porous asphalt and a plastic fill 20 is laid in the space between the layers of non-porous asphalt. This porous asphalt mixture with plastic fill can be obtained in the same way as described with reference to Fig. 3. According to a further alternative, bridging elements 4 are placed on the steel plate 10 in advance and the layer of non-porous asphalt 18 is then laid over the top of these.

[0028] In the variant in Fig. 5 the joint construction has been obtained with completely prefabricated bridging units 19. These bridging units 19, which, for example, can be constructed in the form of tiles, are obtained by applying a wearing course of non-porous asphalt, or an impregnated layer of porous asphalt, to the bridging element 4, as shown in Figs 1 and 2. The bridging units can be placed in position and anchored by an adhesive in a slot 21 made to size in the wearing course 18.

[0029] Finally, an embodiment is also mentioned with which the wearing course on the bridging elements consists of "bare" stone chippings (instead of porous asphalt) which have been heated beforehand and are introduced into the gap between the various layers of non-porous asphalt and then filled with flexible plastic analogously to the porous asphalt variant.

[0030] Figs 6 and 7 show a plan view of and a cross-section through a bridging unit 19 as used in the embodiment in Fig. 5. This bridging unit 19 comprises a bridging element 4, as shown in Figs 1 and 2, that is indicated in its entirety by 4, on top of which a mixture of porous asphalt and a plastic fill 20 has been applied.

[0031] The membrane 2 of the bridging element 4 is stuck to the underside of this mixture 20. The adhesive layer 3 covers a large portion of the underside of the bridging unit 19 and can be stuck to the base as shown in Fig. 5.

Claims

1. Bridging material (1 - 3) for a joint (9, 15) in a pavement, such as a joint (9, 15) at the location of an abutment (6) and a bridge deck (7), which bridging material (1 - 3) is intended to be laid with a base course on the sections (5, 7; 13, 14) enclosing the joint (9, 15), and the top of which bridging material (1 - 3) is intended for applying thereon a continuous wearing course of wearing course material (16, 20), comprising at least a continuous layer (1) of material as well as a series of strips (3) of a relatively hard material which are arranged alongside one another and are intended to be laid transversely over the joint (9, 15) and each have two opposing ends, the one series of ends of which series of strips (3) can be placed on one of the sections (5, 7; 13, 14) enclosing the joint (9, 15) and the other series of ends can be placed on the other section (5, 7; 13, 14) thereof, characterised in that at least two ends of at least one series of ends of the series of strips (3) are offset with respect to a line running transversely to the strips (3).

2. Bridging material according to Claim 1, wherein the strips (3) are offset with respect to one another in their longitudinal direction.

3. Bridging material according to Claim 1, wherein the strips are symmetrical with respect to a common line of symmetry and at least two strips are of unequal length.

4. Bridging material according to one of the preceding claims, wherein the layer (1) of material comprises an adhesive layer that determines the lower surface and can be stuck to the base course.

5. Bridging material according to one of the preceding claims, wherein a top layer or bearing layer (2) such as a membrane, is provided that determines the top surface and the strips are accommodated between the adhesive layer (1) and the top layer (2).

6. Bridging material according to one of the preceding claims, wherein each layer (1, 2) and the series of strips (3) are attached to one another.

7. Bridging material according to one of the preceding claims, wherein the adhesive layer (1) comprises a bitumen.

8. Bridging material according to Claim 7, wherein the adhesive layer (1) is self-adhesive.

9. Joint construction, for example at the location of the transition between an abutment (5) and a bridge deck (7), comprising two sections (5, 7; 13, 14) enclosing a joint (9, 15), a bridging material (1 - 3) that bridges the joint (9, 15) and bears on both sections (5, 7; 13, 14), as well as a wearing course (18, 16) that extends continuously over the sections (5, 7; 13, 14) and the bridging material (1 - 3), the bridging material (1 - 3) comprising a series of strips (3) made of a relatively hard material arranged alongside one another in the direction of the joint (9, 15), characterised in that the ends of at least two strips (3) located on one side of the joint (9, 15) are at unequal distances from said joint (9, 15).

10. Joint construction according to Claim 9, wherein the strips (3) are attached to one another.

11. Joint construction according to Claim 9 or 10, wherein an adhesive layer (1) is provided.

12. Joint construction according to Claim 9 or 10, wherein the adhesive layer is the bottom layer (1) and comprises a bitumen.

13. Joint construction according to Claim 12, wherein the adhesive layer (1) is self-adhesive.

14. Joint construction according to one of Claims 9 - 13, wherein an upper layer (2) is provided that comprises a membrane.

15. Joint construction according to Claims 9 - 14, wherein the strips (3) are offset with respect to one another in their longitudinal direction.

16. Joint construction according to one of Claims 9 - 14, wherein the strips are symmetrical with respect to a common line of symmetry and at least two strips are of unequal length.

17. Joint construction according to one of Claims 9 -14, wherein at its opposing edges parallel to the joint (9, 15) the top layer (2) protrudes with respect to the adhesive layer (1) and the strips (3), and the protruding ends are attached to the sections (5, 7; 13, 14).

18. Joint construction according to one of Claims 9 -17, wherein the joint (9) is covered by a steel plate (10) over which the bridging material (1 - 3) extends (Fig. 4).

19. Joint construction according to one of Claim 9 - 17, wherein the joint (9) is covered by a steel plate (10) over which a layer of non-porous asphalt (13, 14) extends in which a secondary joint (15) is located, and the bridging material (1 - 3) extends over the layer of non-porous asphalt (13, 14) and the secondary joint (15) located therein.

20. Joint construction according to one of the preceding Claims 9 - 19, wherein the wearing course (18; 16) comprises a layer of non-porous asphalt at the location of and on either side of the joint (9; 15).

21. Joint construction according to one of Claims 9 - 19, wherein the wearing course (18; 16) comprises a layer of porous asphalt impregnated with a flexible filler at the location of and on either side of the joint (9; 15).

22. Bridging unit (19) comprising a bridging material according to one of the preceding Claims 1 - 8, comprising an adhesive layer (1) that defines a lower surface, a top layer (2) that defines a top surface and a series of strips (3) of a relatively hard material arranged alongside one another, which series of strips (3) is accommodated between the two layers (1, 2) and which strips (3) are intended to be laid transversely over the joint (9, 15), as well as a layer of non-porous asphalt stuck thereto.

23. Bridging unit (19) comprising a bridging material according to one of the preceding Claims 1 - 8, provided with an adhesive layer (1) that defines a lower surface, a top layer (2) that defines a top surface and a series of strips (3) of a relatively hard material arranged alongside one another, which series of strips (3) is accommodated between the two layers (1, 2) and which strips (3) are intended to be laid transversely over the joint (9, 15), as well as a layer of porous asphalt, impregnated with a filler, stuck thereto.

24. Joint construction comprising two sections (5, 7; 13, 14) enclosing a joint, as well as a bridging unit (19) according to Claim 22 or 23.

Drawing