EP0733738B1 - Method of manufacture of a rail support and support obtained according to this method - Google Patents

Abstract

The rail support sleeper comprises a block (2) of reinforced concrete (38) and a visco-elastic bedplate (8). The block upper face takes the rail and its lower face (6) supports the block on ballast. The bedplate covering the lower face acts as an intermediate support between the ballast and the block. The manufacturing procedure involves a visco-elastic plate (18) having the same dimensions as the bedplate is prefabricated. During this phase chippings (27) are regularly distributed and attached onto one face (20) of the plate. The block is made by moulding concrete in a mould and the prefabricated plate integrated with it to form the bedplate. During moulding the plate is placed so that its chipping face coincides with the block lower face so that the chippings are integrated into the concrete.

Description

a) préfabriquer une plaque en matériau visco-élastique, aux dimensions de la semelle à réaliser,

b) fabriquer le bloc par moulage de béton dans une empreinte en y intégrant la plaque préfabriquée pour constituer la semelle, et

c) autoriser ou provoquer la prise du béton puis démouler le bloc portant solidairement la semelle.

The present invention relates to a method of manufacturing a railway rail support, such as a cross member, comprising at least one concrete block having in particular an upper face intended to receive at least one rail and a lower face intended to ensuring the support of the block on a substrate, such as a ballast, and a sole of visco-elastic material integrally covering this lower face and intended to serve as a support intermediate between the block and the substrate, said method comprising the succession of steps consisting in:

a) prefabricating a plate of visco-elastic material, to the dimensions of the sole to be produced,

b) manufacturing the block by molding concrete in an imprint by integrating the prefabricated plate into it to constitute the sole, and

c) authorize or cause the setting of the concrete then unmold the block carrying the sole securely.

It also relates to a rail rail support likely to be obtained by implementing this process.

We know that the interposition of a sole of a viscoelastic material suitably chosen, such as a dense and hard polyurethane, between the single concrete block of a monobloc sleeper or each block of concrete from a bi-block sleeper, or any concrete block from any rail support railroad, and ballast avoids the attrition of concrete and ballast as well as the compaction thereof, as well as dissipating the energy vibration generated by rolling loads, that is to say in particular of reduce noise when passing a train.

In particular, EP-A-0 465 390 proposes to fix such a sole to the or to each concrete block of a sleeper or any other rail support, by proposing different modes of joining, namely a projection or a casting of the visco-elastic material on the concrete, an integration of prefabricated plates of visco-elastic material to concrete, during the manufacturing the rail support, such as a cross member, by molding at least a concrete block, or by bonding such prefabricated plates on concrete, by any suitable adhesive.

However, currently, the only process actually used to fixing the base to the concrete is a projection of the material visco-elastic with a spray gun, directly on concrete, after drying full of it. This requires a particularly smooth surface condition concrete, on which it is generally necessary to perform for this purpose a resumption of finishing, and lengthens the manufacturing time of the sleepers or other supports since at the time of drying of the concrete of these the projection and setting time of the visco-elastic material is added. In addition, it is difficult to ensure uniform thickness in this way. sole.

The technique of prefabricating the soles in the form of sheets of visco-elastic material and then integrate them into the concrete when molding it or sticking it on it during or after its taken overcomes this drawback, but it remained for the moment without follow-up. Indeed, fixing by gluing certainly allows securing the sole to the underside of the block in satisfactory conditions of homogeneity, but it has the disadvantage to slow production; fixing by integration with concrete during its molding certainly does not lengthen the manufacturing of the sleepers or other rail supports in the sense that the prefabricated plates can be manufactured in masked time and their integration into the cross requires no additional intervention other than their installation in the mold before pouring the concrete, but the anchoring of footings on concrete only result from mutual embedding tightly located, so that the soles remain independent of concrete and free to deform elsewhere, and this mutual embedding has low mechanical strength.

The object of the present invention is to improve the binding a visco-elastic sole prefabricated to the concrete of a support block of rail such as a cross member, so as to improve the homogeneity and the effectiveness of fixing the footing to concrete while retaining the advantages of speed of implementation and uniformity of thickness of the sole, resulting from its direct integration into concrete molding and the prefabrication thereof.

• lors de l'étape a), on fixe à une face de la plaque, destinée à être tournée vers le bloc, des gravillons similaires à ceux du béton de telle sorte que ces gravillons forment une saillie sur la face ainsi gravillonnée et soient régulièrement répartis sur celle-ci, et
• lors de l'étape b), on dispose la plaque préfabriquée, par rapport à l'empreinte, de telle sorte que la face gravillonnée coïncide avec une zone de l'empreinte correspondant à la face inférieure du bloc et soit tournée vers l'intérieur de l'empreinte, et que les gravillons de la face gravillonnée s'intègrent ainsi au béton.

To this end, the present invention provides a method of the type indicated in the preamble, characterized in that:

• during step a), gravel similar to that of concrete is fixed to a face of the plate, intended to be turned towards the block, so that these gravel protrude from the face thus gravelled and are regularly distributed on it, and
• during step b), the prefabricated plate is placed, with respect to the imprint, so that the gravelled face coincides with an area of the imprint corresponding to the underside of the block and is turned inward of the imprint, and that the gravel on the gravel face is thus integrated into the concrete.

Insofar as the rail rail support thus obtained differs from railway rail supports obtained by previously known techniques, including the techniques described in EP-A-0 465 390, the present invention also provides a support railway rail, such as a sleeper, having at least one block of concrete having in particular an upper face intended to receive at least one rail and one lower face intended to ensure the support of the block on a substrate, such as a ballast, and a sole made of visco-elastic material integrally covering this underside and intended to serve support intermediary between the block and the substrate, characterized in that concrete chippings, regularly distributed on one side of the footing facing the underside of the block, are directly and individually secured with the visco-elastic material of the sole.

A skilled person will readily understand that the distribution regular gravel of the gravel face of the prefabricated plate, that is to say from the sole face facing the underside of the block of concrete, ensures a distributed anchoring of the sole in the concrete, that is to say to fix the sole as homogeneously as possible to the concrete. In addition, since the connection between the concrete and the footing is provided by gravel, this fixing can be made much more resistant, in particular to shear forces, that a secure fixation by simple localized mutual embedding, on the one hand because it works the specific characteristics of the gravel and on the other hand due to the distribution of shear forces, resulting from the distribution of gravel.

Naturally, the advantages inherent in the use of a prefabricated plate that is integrated into the concrete during the molding thereof, namely the advantages of rapid production, since the installation of the sole is carried out as soon as the concrete is molded and does not require subsequent recovery thereof, and homogeneity of the thickness of the sole, since the plate can be prefabricated with all the precision required, particularly with regard to its ratings.

The imprint area corresponding to the underside of the block of concrete to be produced can be defined by a wall defining the footprint, in which case the prefabricated plate is placed against this wall, during step b), before pouring the concrete into the cavity.

However, an embodiment is preferred according to which said zone of the imprint is open and turned upwards during step b), in which case step b) is implemented by first filling the concrete footprint to constitute the underside of the block by the free surface of the concrete and then applying on it, before setting concrete, the gravel side of the prefabricated plate in operating conditions capable of causing the integration of gravel from the face graveled with concrete.

In order for this integration to be carried out as homogeneously and efficient as possible, preferably smooth the free surface of the concrete before applying the gravel side of the prefabricated plate, which ensures effective penetration of all gravel in fresh concrete.

This smoothing is advantageously carried out by tamping, that is to say by application of pressure and preferably vibration, which have effect of causing a rise in the laitance of the concrete.

When the quantity of milt thus rising is sufficient, we then apply the gravel side of the prefabricated plate to the free surface of concrete under operating conditions, in particular pressure and preferably vibration, which results in flooding gravel on the gravel face in the laitance and filling, by it, of the intermediate space between the free surface of the concrete and the prefabricated plate without any additional material for this purpose.

However, in the case of a concrete insufficiently rich in milt, we can also bring to the free surface of the concrete, between the filling of the concrete footprint or smoothing according to preferably this filling and applying the gravelled side of the plate prefabricated on the free surface of concrete, a complement of a material constituting concrete, in the fluid state, chosen from a group comprising especially water, pure cement and cement with sand added, to which case we then apply the gravel side of the prefabricated plate to the free surface of the concrete under operating conditions, in particular pressure and preferably vibration as it results integration of gravel from the gravel face of the plate prefabricated with the filler material and the filling, by the latter, of the space between the free surface of the concrete and the plate prefabricated.

In either case, you get a homogeneous concrete until contact with the visco-elastic material constituting the sole.

It facilitates, as appropriate, the proper integration of the gravel from the gravel side with laitance or filler material, giving the prefabricated plate with dimensions, in plan, smaller than those of free surface of concrete. This precaution notably facilitates the evacuation of air likely to remain trapped between the plate precast and concrete. In this regard, a railroad rail support according to the invention is characterized in that the sole has dimensions, in plan, smaller than those of the lower face of the block.

Preferably, the mechanical resistance of the sole is improved by integrating, during step a), a reinforcement with visco-elastic material of the prefabricated plate, the rail support according to the invention then being characterized in that the visco-elastic material of the sole includes such a frame.

Preferably, this reinforcement defines meshes of dimensions smaller than the particle size of the gravel of the prefabricated plate, that is to say chippings attached to the sole, which facilitates the implementation work of step a) according to a method consisting in fixing the gravel to the plate by partially integrating them into the visco-elastic material, this which makes the support according to the invention then characterized in that the pebbles attached to the sole protrude from the underside of the block and are partially integrated into the visco-elastic material of the sole. Thus, according to a preferred embodiment, the gravel of the prefabricated plate form therefrom a projection with a height of on the order of 50% to 95% of their height, measured perpendicular to the gravel face, so that the gravel attached to the sole is integrated into the visco-elastic material thereof over a height of the order from 5% to 50% of their height, measured perpendicular to the face bottom of the block.

In such a case, in fact, it is advantageously prefabricated plate, during step a), by melting, forming and solidifying the material visco-elastic, chosen hot-melt, and we partially integrate the gravel in the visco-elastic material by sowing them on it between forming and solidification. If the visco-elastic material intended to constitute the prefabricated plate then the sole includes a frame, and if this reinforcement defines meshes of dimensions lower than the grading of the gravel of the prefabricated plate, this reinforcement is opposed to the gravel thus sown between forming and solidification of the visco-elastic material pass through this material up to reach the face of the prefabricated plate intended to constitute the face support of the sole on the ballast, and thus preserves the homogeneity of this bearing face on the ballast.

Preferably, the gravel of the prefabricated plate, that is to say the gravel attached to the sole, have the same nature and the same grain size than those of concrete, and leave between them spaces whose dimensions correspond as much as possible to their grain size, which on the one hand facilitates the insertion of gravel from the prefabricated plate between those of the concrete intended to constitute the block during of the pouring of this concrete and on the other hand ensures homogeneity of the distribution of gravel in concrete to the immediate vicinity of the sole.

In this respect, moreover, the gravel of the prefabricated plate, that is to say the gravel attached to the sole, cover from 80% to 95% of the gravel side of the prefabricated plate, i.e. still from the side bottom of the block.

It is preferably a crushed with sharp edges, a particle size of the order of 3 mm / 10 mm, preferably 4mm / 8mm, but these figures, like the aforementioned figures, constitute only one nonlimiting example.

• Les figures 1 et 2 montrent des vues d'une traverse selon l'invention, partiellement encastrée dans du ballast et portant deux rails, respectivement suivant la direction des rails et perpendiculairement à celle-ci.
• Les figures 3 et 4 illustrent deux phases successives de l'étape a) de préfabrication de la plaque en matériau visco-élastique présentant une face gravillonnée, en coupe par un plan courant perpendiculaire à cette face.
• La figure 5 illustre, en une vue analogue à celle des figures 3 et 4, l'intégration des gravillons de la plaque au béton armé constituant le bloc.
• Les figures 6 à 9 illustrent quatre phases successives de l'étape b) de fabrication de la traverse par moulage de béton avec intégration d'armatures et de la plaque en matériau visco-élastique, la traverse en cours de fabrication étant vue en bout comme c'est le cas à la figure 2.
• La figure 10 illustre l'une des phases de l'étape c) de prise du béton avant démoulage.
• La figure 11 indique une répartition granulométrique de gravillons ayant donné tout satisfaction pour le gravillonnage de la plaque en matériau visco-élastique et la charge du béton d'une traverse conforme à la présente invention, à titre d'exemple non limitatif.

Other characteristics and advantages of the method and of the rail rail support according to the invention will emerge from the description below, relating to a nonlimiting example, as well as from the appended drawings which form an integral part of this description.

• Figures 1 and 2 show views of a crosspiece according to the invention, partially embedded in ballast and carrying two rails, respectively in the direction of the rails and perpendicular thereto.
• Figures 3 and 4 illustrate two successive phases of step a) of prefabrication of the plate of visco-elastic material having a gravelled face, in section through a current plane perpendicular to this face.
• FIG. 5 illustrates, in a view similar to that of FIGS. 3 and 4, the integration of the gravel from the plate with the reinforced concrete constituting the block.
• FIGS. 6 to 9 illustrate four successive phases of step b) of manufacturing the cross member by molding concrete with integration of reinforcements and of the plate of visco-elastic material, the cross member during manufacture being viewed at the end as this is the case in Figure 2.
• FIG. 10 illustrates one of the phases of step c) of setting the concrete before demolding.
• FIG. 11 indicates a particle size distribution of gravel having given all satisfaction for the graveling of the plate of visco-elastic material and the load of the concrete of a crosspiece according to the present invention, by way of nonlimiting example.

Although the example which will be described is that of manufacturing a railway sleeper formed from a single block of reinforced concrete prestressed, a skilled person will easily understand that the present invention also applies to the manufacture of any other support rail comprising at least one concrete block, namely in particular the bi-block sleepers, comprising two reinforced concrete blocks connected by a spacer, the switchgear supports, the blocks intended for receive a rail individually, and it will bring to the arrangements that are going be described the modifications necessary in each case, without going out to as much of the scope of the present invention.

Referring first to Figures 1 and 2, it will be recalled that a monobloc cross member 1, made of prestressed reinforced concrete, has the general shape of a block 2 of concrete, elongated in a direction longitudinal 3 perpendicular to the rail 4 to be supported. If we refer to an installation position, in which the cross member 1 is partially embedded in ballast 5, block 2 is delimited by a lower face plane 6, longitudinal, parallel to the rolling plane 7 of the rails, this lower face 6 being embedded in the ballast 5 and resting on it, flat, by means of a sole 8 of a chosen visco-elastic material for example in accordance with the teachings of EP-A-0 465 390, and a upper face 9 which is essentially flat and parallel to the face lower 6 in the example illustrated but could present other conformations, and receives the two rails 4 directly or, as it is illustrated, via saddles 10, with elastic fixing of the rails 4 by means 11 not detailed and well known to a person skilled in the art. The block 2 is also delimited by two flat longitudinal faces 12 connecting the lower face 6 to the lower face 9 by converging from the first to the second, so as to communicate to the block 2 a cross section in the form of an isosceles trapezoid, and in pairs transverse end faces 13 also flat, also connecting the lower face 6 to the upper face 9 and further connecting mutually the two longitudinal faces 12, these two faces 13 being approximately transverse and converging mutually from the face lower 6 towards the lower face 9 so that when viewed in section through a longitudinal plane perpendicular to these faces 6 and 9, the crosspiece also has a section essentially in the form of isosceles trapezoid. This mutual upward convergence on the one hand of longitudinal faces 12 and secondly transverse end faces 13 is intended to facilitate the release of the block 2, when it is molded according to a technique which will be described later, and has the advantage of cause it to anchor in ballast 5, which drowns faces 12 and 13 on the most of their height as appears from the examination of Figures 1 and 2. However, it is understood that other forms could be chosen without departing from the scope of the present invention, the only one with regard to the latter the flatness of the lower face 6 of this block 2.

In accordance with the present invention, and in a manner known per se, the sole 8 presents in contact, flat, with the lower face 6 of the block 2 a flat upper face 14 integral with this lower face 6 while it presents downwards, that is to say in contact with the ballast 5, a lower face 15 also planar, parallel to the upper face 14 and close enough to it that the sole 8, considered in isolation, has the form of a plate with a thickness of the order of 3 to 10 mm, preferably around 4 mm, these figures only being indicated as a nonlimiting example. The two faces 14 and 15 are connected mutually by a song 16 which is perpendicular to them and their communicates a rectangular shape which can be identical to that of the lower face 6 of block 2, that is to say in particular having the same dimensions as this lower face 6 so that the sole 8 fully covers the latter, in a manner known per se, or be approximately identical to that of the underside 6, and more precisely present dimensions of a few millimeters to those of this underside 6 so that the sole 8 covers practically the whole of it, leaving however remain a free peripheral zone 17 whose presence facilitates the manufacture of the assembly integral with block 2 and sole 8 in accordance with the present invention, as will appear below, and whose direct contact with ballast 5 presents little disadvantage in the since this zone 17 is limited to the immediate vicinity of the connection of the lower face 6 with the longitudinal faces 12 and the transverse end faces 13.

In a manner known in itself, the plate constituting the sole 8 is prefabricated before being integrated into the concrete constituting block 2, at the manufacturing of it, but a specific method of prefabrication, constituting a preferred embodiment of the present invention, will now be described with reference to FIG. 3, as regards the prefabrication process, and Figure 4 with regard to the plate prefabricated obtained, intended to constitute the sole 8.

FIG. 3 shows that a plate 18 is initially manufactured having a lower face 19 and an upper face 20 flat, mutually parallel, separated by a thickness e corresponding to the thickness e of the sole 8 measured between its upper face 14 and its face lower 15, with plan dimensions which may be those of the sole 8 to be produced, or even to be much higher for correspond to the soles 8 of several sleepers 1, in which case cuts the plate 18 at any time preceding its integration, as sole 8, into the concrete constituting the block 2 of each cross member, respectively.

• réaliser une première couche 21 de matériau visco-élastique à l'état fondu, cette première couche 21 définissant la face 19 et une partie, par exemple environ la moitié, de l'épaisseur e de la plaque 18 à partir de cette face 19;
• alors que le matériau visco-élastique de la première couche 21 est encore fluide, déposer sur cette première couche 21 une armature textile 22, par exemple tissée de façon à définir des mailles 23, notamment un voile de polyester à 80g/m2 ;
• déposer ensuite sur l'armature 22 une deuxième couche 24 de matériau visco-élastique en fusion, qui s'ancre sur la première couche 21 à travers l'armature 22 et constitue le reste de l'épaisseur e de la plaque 18, jusqu'à la face supérieure 20 de celle-ci ;
• alors que le matériau visco-élastique de la deuxième couche 24 est encore à l'état fluide, et que la face inférieure 19 de la plaque 18 repose à titre provisoire sur une face supérieure horizontale, plane 25 d'un support approprié 26, semer sur la face supérieure 20, tournée vers le haut, des gravillons 27 propres, c'est-à-dire dépoussiérés, de même nature et de même granulométrie que les gravillons utilisés pour le béton constitutif du bloc 2 à réaliser, lesquels gravillons 27 s'enfoncent partiellement dans la deuxième couche 24 sans atteindre la première couche 21 ; en effet, les mailles 23 de l'armature 22 présentent une dimension inférieure à la granulométrie des gravillons 27, qui ne peuvent la traverser et dont la pénétration dans la plaque 18 est donc limitée à la deuxième couche 24 de celle-ci ;
• autoriser ou provoquer la prise du matériau visco-élastique des couches 21 et 24, qui se solidarisent mutuellement à travers l'armature 22 et ancrent définitivement les gravillons 27 dans la plaque 18, dont la structure finale est illustrée à la figure 4.

The plate 18 consists of the visco-elastic material intended to constitute the sole 8, which is advantageously chosen to be of hot-melt nature, and for example consists of a polyurethane chosen according to the specifications of EP-A-0 465 390, in particular a polyurethane of hardness 70 shore A. Then, the plate 18 can advantageously be prefabricated by the succession of steps consisting in:

• producing a first layer 21 of visco-elastic material in the molten state, this first layer 21 defining the face 19 and part, for example about half, of the thickness e of the plate 18 from this face 19;
• while the visco-elastic material of the first layer 21 is still fluid, deposit on this first layer 21 a textile reinforcement 22, for example woven so as to define meshes 23, in particular a polyester veil at 80 g / m2;
• then deposit on the frame 22 a second layer 24 of visco-elastic molten material, which is anchored on the first layer 21 through the frame 22 and constitutes the rest of the thickness e of the plate 18, up to to the upper face 20 thereof;
• while the visco-elastic material of the second layer 24 is still in the fluid state, and the lower face 19 of the plate 18 rests provisionally on a horizontal, planar upper face 25 of a suitable support 26, sow on the upper face 20, facing upwards, clean gravel 27, that is to say dust-free, of the same nature and of the same particle size as the gravel used for the concrete constituting the block 2 to be produced, which gravel 27 s '' partially sink into the second layer 24 without reaching the first layer 21; in fact, the meshes 23 of the frame 22 have a dimension smaller than the particle size of the gravel 27, which cannot pass through it and whose penetration into the plate 18 is therefore limited to the second layer 24 thereof;
• authorize or cause the setting of the visco-elastic material of the layers 21 and 24, which join together through the reinforcement 22 and permanently anchor the gravel 27 in the plate 18, the final structure of which is illustrated in FIG. 4.

It appears from this figure that the gravel 27, all located on the same side of the reinforcement 22 as the layer 24, now integral with the layer 21 to through the meshes 23 of the frame 22, form a projection on the face 20 of the plate 18, evenly distributed on this face 20 and in leaving free spaces between them, thereon 28 whose dimensions correspond as much as possible to their particle size, which is also that of the gravel intended to enter into the composition of the concrete constituting block 2.

By way of nonlimiting example, using in particular as gravel 27 a sharp-lime crushed sand-lime particle size of 3 mm / 10 mm, preferably 4 mm / 8 mm, in particular a crushed responding to particle size analysis by sieving out of Figure 11, which should be considered as integrated into this description, we obtained good results by covering from 80% to 95% of the surface of the face 20 by the gravel 27, and by forming by these last, perpendicular to face 20, a projection with a height h of around 50% to 95% of their height H, also measured perpendicular to the gravelled face 20; in other words, the gravel 27 were integrated into the visco-elastic material of the plate 18 over a depth p, measured perpendicular to the face gravelled 20, of the order of 5% to 50% of their height H, it being understood that this depth p is equal to the difference between H and h, on the one hand, and is less than the thickness e of the plate 18, and more precisely at most equal to the unreferenced thickness of layer 24, itself for example approximately equal to half the thickness e, on the other hand.

If the plate 18 thus produced has dimensions in plan corresponding to several soles 8, it is then cut into a certain number of elementary plates each of which has the dimensions required to constitute a respective sole 8, as will be understood easily a skilled person. For reasons of simplicity, we will subsequently keep the same reference number 18 to designate a plate made directly to the dimensions of a sole 8 determined or a plate obtained by cutting a plate 18 corresponding to several soles 8.

A plate 18 thus defined, having dimensions corresponding to those of a sole 8, is integrated into the concrete constituting the block 2 of a cross member 1 to be produced, to constitute the sole 8 thereof, under operating conditions which will now be described, in reference to Figures 6 to 10.

These operating conditions differ little from the operating conditions usual manufacturing of sleepers, so that they will not be described in broad outline, except for operations installation and integration of the prefabricated plate 18.

In the nonlimiting example illustrated, in a manner known per se, we use for the molding of the reinforced concrete constituting the block 2 a mold 29 which is removably hung on a vibrating table 30, in a position of use which will serve as a reference to the description succinct, below, of this mold 29 well known to a person skilled in the art.

• une face de fond 32 reproduisant, en négatif, la géométrie de la face 9 du bloc 2 à mouler et présentant une orientation générale horizontale,
• deux faces de flanc planes 33 occupant par rapport à la face de fond 32 la même position que les faces longitudinales 12 du bloc 2 à réaliser par rapport à la face supérieure 9 de celui-ci, c'est-à-dire notamment s'écartant mutuellement vers le haut, à partir de leur raccordement à la face de fond 32, de façon à donner à l'empreinte 31 une forme évasée, la dimension des deux faces de flanc 33 dans le sens de la hauteur étant sensiblement identique à la dimension correspondante des faces longitudinales 12 à réaliser,
• deux faces d'extrémité 34 occupant par rapport à la face de fond 32 et aux faces de flanc 33 une position respective identique à celle des faces d'extrémité transversale 13 du bloc 2 à réaliser par rapport à la face supérieure 9 et aux faces longitudinales 12 de celui-ci, respectivement, avec un dimensionnement dans le sens de la hauteur sensiblement identique à celui des faces d'extrémité transversale 13 et un écartement mutuel vers le haut, à partir du fond 32, propre à donner à l'empreinte 31 une forme évasée vers le haut.

This mold 29 defines, for the molding of concrete, a footprint 31 fully open upwards, and delimited by;

• a bottom face 32 reproducing, in negative, the geometry of the face 9 of the block 2 to be molded and having a generally horizontal orientation,
• two flat side faces 33 occupying with respect to the bottom face 32 the same position as the longitudinal faces 12 of the block 2 to be produced with respect to the upper face 9 thereof, that is to say in particular s' spreading each other upwards, from their connection to the bottom face 32, so as to give the imprint 31 a flared shape, the dimension of the two flank faces 33 in the direction of the height being substantially identical to the corresponding dimension of the longitudinal faces 12 to be produced,
• two end faces 34 occupying with respect to the bottom face 32 and the side faces 33 a respective position identical to that of the transverse end faces 13 of the block 2 to be produced with respect to the upper face 9 and to the longitudinal faces 12 thereof, respectively, with a dimensioning in the direction of the height substantially identical to that of the transverse end faces 13 and a mutual spacing upwards, from the bottom 32, suitable for giving the impression 31 an upward flared shape.

The flank 33 and end 34 faces, connecting in pairs, thus connect the bottom 32 to a flat, horizontal upper face 35 of the mold 29, at the level of which these flank 33 and end 34 faces define a fully open filling opening 36, rectangular like the underside 6 of the block 2 to be produced and having dimensions slightly larger than those of this face 6.

In a manner also known in itself, the mold 29 has means, not detailed, for temporarily stretching between the faces end 34 of the prestressing armatures 37 of the block 2 in compression, and may have various provisions, in particular at bottom level 32, for possibly receiving organs to be integrated to the concrete of block 2 with a view to fixing the saddles 10, in the form of inserted dowels or studs, not shown but well known of a skilled person.

The reinforcements 37 having been put in tension inside the imprint 31 and the other frames of block 2 to be produced having been placed also in place in this imprint 31, as well as any organ to integrate into the concrete in particular for fixing the saddles 10, we sink in the footprint 31 the concrete 38 intended to constitute the block 2, making vibrate the vibrating table 30 under the usual operating conditions, as shown in Figure 6.

The footprint 31 is thus substantially filled with concrete 38 which, at the end of this filling, presents a free surface upwards 39 approximately flat and approximately level with the face upper 35 of the mold 29, in the filling opening 36, as it spring of FIG. 7 which illustrates a next phase of the manufacture of the block 2. This phase consists in grooming the free surface 39 in particular for the make it smooth and flat, that is to say give it the conformation of the face lower 6 of block 2 that it is intended to constitute. Concrete 38, at the interior of the imprint 31 then has the shape of the block 2 to be produced. This damage also has the effect of causing, if possible taking into account the composition of concrete 38, a rise in milt at the level of the surface 39, this possible rise in milt being used according to one preferred embodiments of the present invention to provide the subsequent anchoring of the plate 18 by its gravelled face 20.

In a known manner, tamping is accompanied by vibrations communicated by the vibrating table 30 and is carried out by means of a lady 40 having the general shape of a rigid plate comprising a face lower plane 41 of tamping, horizontal and having a shape rectangular plane, corresponding to that of face 6 to be produced, so as to be able to be moved towards the inside of the impression 31 by applying pressure on the face 39 until occupying with respect to the bottom 32 of the imprint 31 a position identical to that of the underside 6 of the block 2 with respect to the upper face 9 thereof. Plate 40 is stiffened for example by a beam 42 which doubles it upwards, and which ensures the connection of this plate 40 to means, simply shown schematically by a vertical double arrow 43, of lifting relative to the mold 29, to clear the filling opening 36, and the descent to this mold 29, that is to say towards the inside of the imprint 31, to effect tamping the free surface 39 of concrete 38 with the application of a pressure to it.

A next step, illustrated in Figure 8, is itself characteristic of the implementation of the present invention and consists in deposit on the groomed free surface 39 of the concrete 38 the plate 18 of which turns the gravel side 20 downwards so that this side gravelled 20 essentially covers the free surface 39 of concrete 38, in a position substantially identical to that which the sole 8 must occupy with respect to the lower face 6 of block 2. Naturally, this deposition takes place while the tamping plate 40 is lifted.

If the quantity of laitance available on surface 39, after damage shown in Figure 7, is insufficient to implement the continuation of the process, under conditions which will be described later, you can between the step illustrated in Figure 7 and the step illustrated in Figure 8 add additional support to the free surface 39 of the concrete constituent material thereof, namely in particular water, pure cement or cement with sand added, preferably without the addition of gravel. Naturally, the material thus provided, comparable to a complement of milt, is in the fluid state, in the same way as the concrete 38 filling the footprint 31.

Then, as shown in Figure 9, we lower the plate tamping 40 towards the imprint 31 so that the face 41 of this plate tamping 40 rests flat on the face 19, then turned upwards, of the plate 18 itself bearing downwards, by its gravel face 20, on the free surface 39 of the concrete 38. One thus applies to the gravelled plate 18 a downward pressure, by means of the tamping plate 40, in vibrating the mold 29 by means of the vibrating table 30, in conditions identical to those which gave rise to an ascent possible milt during tamping described with reference to Figure 7, so as to drive in the gravel 27 from the gravel face 20 of the plate 18 in the fresh concrete defining the free surface 39, until the free spaces 28 of the gravelled face 20 of the plate 18 come themselves apply under pressure to concrete 38, which coats the entire portion of the gravel 27 projecting from the gravel face 20 of the plate 18. Taking into account that the gravel 27 have a grain size identical to that of concrete gravel 38, on the one hand, and delimit between them free spaces 28 having dimensions corresponding at most to this particle size, other hand, gravels 44 of concrete 38 are inserted in the spaces free 28 between the gravel 27 during this phase of penetration of these last in concrete 38, as shown in Figure 5 illustrating the crosspiece 1 finished, in position of use, so that the gravel 27 are embedded in concrete 38 under the same conditions as gravel 44, and the identity of nature between the gravel 27 and the gravel 44 ensures homogeneity of concrete 38 until contact with the gravel face 20 of plate 18. It is understood, however, that concrete 38 can in addition to containing gravel with a grain size greater than that of chippings 44, in a manner known per se. Depending on the case, the continuity between the gravel 44 and 27 is ensured by the only laitance raised during the tamping illustrated in Figure 7, or by the filler material deposited on the free surface 39 between the steps illustrated in FIGS. 7 and 8 in the case where the quantity of laitance thus available would be insufficient; excess any laitance or filler material can drain upwards around the plate 18, taking into account the aforementioned dimensioning thereof.

It will be noted that the preferred choice, for the plate 18 intended for constitute the sole 8, of plan dimensions slightly smaller than those of the lower face 6 of the block 2 to be produced, that is to say those of the free surface 39 of concrete 38 inside the cavity 31, facilitates also the evacuation of air which could tend to remain trapped between the plate 18 and the concrete 38, that is to say allows to obtain a contact as intimate as possible between the concrete 38, on the one hand, the gravel 27 and, by the free spaces 28 between them, the face 20 of the plate 18, on the other hand.

By way of nonlimiting example, good results have been obtained in driving the gravelled plate 18 into the fresh concrete 38 using the aforementioned vibration and a pressure of the order of 7000 N / m2 for 10 to 20 seconds, but these figures are given as a limiting example.

When the concrete 38 has sufficiently set, the lady 40 is lifted and the vibration stopped, and the mold 29 is detached from the vibrating table 30 to transport it to an intermediate storage area or, as illustrated in figure 10, towards an oven to authorize or cause the setting concrete 38. During this setting, as shown in Figure 10, the molds 29 are preferably turned over, that is to say rest by their face 35 on a horizontal support, plane 45, so that the concrete 38 rests on it support 45 by means of the gravelled plate 18 and contributes, by its own weight, to preserve the integration of the gravel 27 thereof to concrete 38; however, it is not beyond the scope of this invention by leaving the face 35 of the molds facing upward during the concrete setting 38.

After the time necessary for the complete taking of it, in conditions identical to the usual conditions, we proceed to demolding and the release of the reinforcements 37 which create a prestress compression in concrete 38, it being understood that demolding could also be done before taking is complete; we obtain thus a cross member 1 according to the invention, including in particular the lower face 6 is constituted by the surface 39, initially free, of the concrete 38 now constituting block 2 and the sole 8 of which is constituted by the plate 18, the gravel face 20 of which constitutes the upper face 14 and whose other face 19 constitutes the lower face 15. The gravel 27, embedded both in the visco-elastic material now constituting the sole 8 and in concrete 38 now constituting block 2, provide a link regularly distributed between the sole 8 and the block 2, so particularly effective, covering the same proportion of the face lower 6 of block 2 than of the upper face 14 of the sole 8, namely in the range of 80% to 95% in the preferred implementation example previously indicated.

Naturally, a person skilled in the art will easily understand that not only the figures indicated, but also the procedure adopted for the molding of concrete 38 and integration of gravel 27 from plate 18 to this could be changed to a large extent without any so far from the scope of the present invention. In particular, we could provide that the molding imprint 31 is shaped so as to carry out the molding of the crosspiece not in an inverted position of this one but in another position, in which case one could be brought to place the plate 18 in this cavity 31 before pouring the concrete 38 into it, the gravelled plate 18 being naturally placed in the area of the imprint 31 intended to produce the lower face 6 of the block 2 of concrete and having its gravel face 20 towards the inside of the imprint 31.

Claims (26)

1. A method of manufacturing a support, such as a sleeper (1), for a railway rail (4), the support comprising at least one block (2) of concrete (38) having in particular a top face (9) for receiving at least one rail (4) and a bottom face (6) whereby the block (2) bears on a substrate (5) such as ballast (5), and a soleplate (8) of viscoelastic material securely covering said bottom face (6) and designed to serve as a bearing intermediary between the block (2) and the substrate (5), said method comprising the succession of steps consisting in:

   a) prefabricating a plate (18) of viscoelastic material, having the dimensions of the soleplate (8) to be made;

   b) manufacturing the block (2) by molding concrete (38) in a mold (31) with the prefabricated plate (18) being included therein so as to constitute the soleplate (8); and

   c) enabling or causing the concrete (38) to set and then unmolding the block (2) securely carrying the soleplate;

      the method being characterized in that:

   during step a) gravel (27) similar to that in the concrete (38) is fixed to one of the faces (20) of the plate (18) that is to face towards the block (2), such that said gravel (27) projects from the face (20) that has been gravelled in this way and is regularly distributed thereover; and

   during step b) the prefabricated plate (18) is placed relative to the mold (31) in such a manner that its gravelled face (20) coincides with a zone (36) of the mold (31) corresponding to the bottom face (6) of the block (2) and faces towards the inside of the mold (31), and the gravel (27) on the gravelled face (2) is thus integrated in the concrete (38).
2. A method according to claim 1, characterized in that said zone (36) of the mold (31) is open and faces upwards during step b), and in that step b) is implemented by initially filling the mold (31) with concrete (38) to constitute the bottom face (6) of the block via the free surface (39) of the concrete (38) and then in applying thereon, prior to the concrete (38) setting, the gravelled face (20) of the prefabricated plate under operating conditions suitable for causing the gravel (27) on the gravelled face (20) to become integrated in the concrete (38).
3. A method according to claim 2, characterized in that the free surface (39) of the concrete is smoothed before the gravelled face (20) of the prefabricated plate (18) is applied thereto.
4. A method according to claim 2 or 3, characterized in that the concrete (38) is subjected to conditions, in particular of pressure and preferably of vibration, having the effect of causing laitance to rise prior to applying the gravelled face (20) of the prefabricated plate (18) on its free surface (39), and in that thereafter the gravelled face (20) of the prefabricated plate (18) is applied on the free face (39) of the concrete (38) under operating conditions, particularly of pressure, and preferably of vibration, such that the gravel (27) of the gravelled face (20) is embedded in the laitance with the laitance filling the gap between the free surface (39) of the concrete (38) and the prefabricated plate (18) without additional material being supplied for this purpose.
5. A method according to claim 2 or 3, characterized in that, between filling the mold (31) with concrete (38) and applying the gravelled face (20) of the prefabricated plate (18) on the free surface (39) of the concrete (38), additional concrete-constituting material is applied thereto in the fluid state, said material being selected from the group comprising in particular water, pure cement, and a mixture of cement and sand, and in that thereafter the gravelled face (20) of the prefabricated plate (18) is applied to the free surface (39) of the concrete (38) under operating conditions, in particular of pressure and preferably of vibration, such that the gravel (27) of the gravelled face (20) of the prefabricated plate (18) is integrated in the additional material which also fills the gap between the free surface (39) of the concrete (38) and the prefabricated plate (18).
6. A method according to any one of claims 1 to 5, characterized in that the prefabricated plate (18) has dimensions in its plane that are smaller than those of the free surface (39) of the concrete (39).
7. A method according to any one of claims 1 to 6, characterized in that, during step a), reinforcement (22) is integrated in the viscoelastic material of the prefabricated plate (18).
8. A method according to claim 7, characterized in that the reinforcement (22) defines a mesh (23) of dimensions smaller than the grain size of the gravel (27) of the prefabricated plate (18).
9. A method according to any one of claims 1 to 8, characterized in that, during step a), the gravel (27) is fixed to the plate (18) by being partially integrated in the viscoelastic material.
10. A method according to claim 9, characterized in that during step a), the plate (18) is prefabricated by melting, forming, and solidifying the viscoelastic material which is selected to be a hot-melt material, and in that the gravel (27) is partially integrated in the viscoelastic material by being seeded thereon between forming and solidification.
11. A method according to claim 9 or 10, characterized in that the gravel (27) of the prefabricated plate (18) projects therefrom over a height (h) of about 50% to 95% of its own height (H) measured perpendicularly to the gravelled face.
12. A method according to any one of claims 1 to 11, characterized in that the gravel (27) of the prefabricated plate (18) is of the same nature and of the same grain size as the gravel of the concrete (38).
13. A method according to any one of claims 1 to 12, characterized in that the gravel (27) of the prefabricated plate (18) leaves gaps (28) of dimensions corresponding to no more than the grain size of the gravel.
14. A method according to any one of claims 1 to 13, characterized in that the gravel (27) of the prefabricated plate (18) covers 80% to 95% of the gravelled face (20).
15. A method according to any one of claims 1 to 14, characterized in that the gravel (27) of the prefabricated plate (18) is crushed gravel and has sharp edges.
16. A method according to any one of claims 1 to 15, characterized in that the gravel (27) of the prefabricated plate (18) has grain size of the order of 3 mm to 10 mm, and preferably of the order of 4 mm to 8 mm.
17. A railway rail support such as a sleeper (1), the support comprising at least one block (2) of concrete (38) having in particular a top face (9) for receiving at least one rail (4) and a bottom face (6) designed to enable the block (2) to bear against a substrate (5) such as ballast (5), and a soleplate (8) of viscoelastic material securely covering said bottom face (6) and designed to serve as a bearing intermediary between the block (2) and the substrate (5), the support being characterized in that the gravel (27) of the concrete, regularly distributed over one face (14) of the soleplate (8) facing towards the bottom face (6) of the block (2) is secured directly to the viscoelastic material of the soleplate, with each piece of gravel being secured individually.
18. A support according to claim 17, characterized in that the soleplate (8) has plane dimensions that are smaller than the plane dimensions of the bottom face (6) of the block (2).
19. A support according to claim 17 or 18, characterized in that the viscoelastic material of the soleplate (8) includes reinforcement (22).
20. A support according to claim 19, characterized in that the reinforcement (22) defines a mesh (23) of dimensions smaller than the grain size of the gravel (27) fixed to the soleplate (8).
21. A support according to any one of claims 17 to 20, characterized in that the gravel (27) fixed to the soleplate (8) projects from the bottom face (6) of the block (2) and is partially integrated in the viscoelastic material of the soleplate (8).
22. A support according to claim 21, characterized in that the gravel (27) fixed to the soleplate (8) is integrated in the viscoelastic material thereof to a depth (p) of about 5% to 50% of its height (H), measured perpendicularly to the bottom face (6) of the block (2).
23. A support according to any one of claims 17 to 22, characterized in that the gravel (27) fixed to the soleplate (8) is of the same kind and of the same grain size as the other gravel (44) of the concrete (38).
24. A support according to any one of claims 17 to 23, characterized in that the gravel (27) fixed to the soleplate (8) covers 80% to 95% of the bottom face (6) of the block (2).
25. A support according to any one of claims 17 to 24, characterized in that the gravel (27) fixed to the soleplate (8) is crushed gravel having sharp edges.
26. A support according to any one of claims 17 to 25, characterized in that the gravel (27) fixed to the soleplate (8) has grain size of the order of 3 mm to 10 mm, and preferably of the order of 4 mm to 8 mm.

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