EP0733738A1 - 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 railway rail support capable of being obtained by implementing this method.

It is known that the interposition of a sole of a suitably chosen viscoelastic material, such as a dense and hard polyurethane, between the single concrete block of a monoblock sleeper or each concrete block of a biblock sleeper, or any concrete block of any rail support, and the ballast prevents the attrition of the concrete and the ballast and the settlement of it, as well as dissipate the vibrational energy generated by the loads rolling, that is to say in particular to reduce noise when passing a train.

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

However, currently, the only process actually used to secure the sole to the concrete is a spraying of the visco-elastic material with a spray gun, directly onto the concrete, after the latter has completely dried. This requires a particularly smooth surface condition of the concrete, on which it is generally necessary to carry out for this purpose. a resumption of finishing, and lengthens the manufacturing time of the sleepers or other supports since the drying time of the concrete of the latter is added the time of projection then setting of the visco-elastic material. In addition, it is difficult to ensure a uniform thickness of the sole in this way.

The technique of prefabricating the soles in the form of visco-elastic material plates and then integrating them into the concrete when it is molded or sticking it on it during or after setting allows to overcome this drawback, but it has so far gone unanswered. Indeed, fixing by gluing certainly makes it possible to ensure the fixing of the sole on the underside of the block under satisfactory conditions of homogeneity, but it has the disadvantage of slowing production; fixing by integration with concrete during its molding certainly allows not to lengthen the manufacture of sleepers or other rail supports in the sense that the prefabricated plates can be manufactured in masked time and that their integration into the sleeper does not require additional intervention other than their placement in the mold prior to pouring the concrete, but the anchoring of the footings on the concrete then results only from a closely localized mutual embedding, so that the footings remain independent of the concrete and free to deform otherwise, and this mutual embedding has low mechanical strength.

The object of the present invention is to improve the fixing of a viscoelastic sole prefabricated to the concrete of a rail support block such as a cross member, so as to improve the homogeneity and the efficiency of the fixing of the sole to the concrete while retaining the advantages of speed of implementation and homogeneity of thickness of the sole, resulting from the direct integration of the latter into the molding of the concrete and the prefabrication of the latter.

• 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 one face of the plate, intended to be turned towards the block, so that these gravel form a projection on 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 cavity corresponding to the underside of the block and is turned towards the interior of the cavity, and that the gravel of the gravelled face thus integrates into the concrete.

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

A person skilled in the art will readily understand that the regular distribution of the gravel on the gravelled face of the prefabricated plate, that is to say on the sole face facing the underside of the concrete block, makes it possible to ensure a distributed anchoring. of the sole in the concrete, that is to say to fix as homogeneously as possible the sole to the concrete. In addition, insofar as the connection between the concrete and the sole is ensured by gravel, this fixation can be made much more resistant, in particular to shearing forces, than a fixation ensured by simple localized mutual embedding, of a firstly because it implements the specific characteristics of the gravel and secondly because of the distribution of the shear forces, resulting from the distribution of the gravel.

Naturally, the advantages inherent in the use of a prefabricated plate are also retained, which are integrated into the concrete during the molding of the latter, namely the advantages of rapid production, since the installation of the sole takes place as soon as the concrete is molded and does not require subsequent recovery of the latter, and homogeneity of the thickness of the sole, since the plate can be prefabricated with all the precision required, particularly as regards its dimensions.

The area of the footprint corresponding to the underside of the concrete block 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 implementation mode 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 thereto, before setting the concrete, the gravelled face of the prefabricated plate under operating conditions capable of causing the integration of gravel from the gravel face to the concrete.

In order for this integration to take place as homogeneously and efficiently as possible, the free surface of the concrete is preferably smoothed before applying the gravelled face of the prefabricated plate, which ensures effective penetration of all the gravel in the fresh concrete.

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

When the quantity of laitance thus rising is sufficient, the gravelled face of the prefabricated plate is then applied to the free surface of the concrete under operating conditions, in particular of pressure and, preferably, of vibration, such that it results in flooding. gravel of the face graveled in the laitance and filling, by the latter, of the intermediate space between the free surface of the concrete and the prefabricated plate without any other material for this purpose.

However, in the case of a concrete insufficiently rich in milt, it is also possible to bring to the free surface of the concrete, between the filling of the concrete imprint or the smoothing following preferably this filling and the application of the gravelled face. of the prefabricated plate on the free surface of the concrete, a complement of a material constituting the concrete, in the fluid state, chosen from a group comprising in particular water, pure cement and cement with sand added, in which case we then apply the gravelled face of the prefabricated plate to the free surface of the concrete under operating conditions, in particular of pressure and, preferably, of vibration, such that the integration of the gravel of the gravelled face of the prefabricated plate results therefrom to the filler material and the filling, by the latter, of the intermediate space between the free surface of the concrete and the prefabricated plate.

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

It facilitates, as the case may be, the good integration of the gravel of the gravel face with the laitance or the filler material, by giving the prefabricated plate dimensions, in plan, smaller than those of the free surface of the concrete. This precaution makes it possible in particular to facilitate the evacuation of air likely to remain trapped between the prefabricated plate and the concrete. In this regard, a railway rail support according to the invention is characterized in that the sole has dimensions, in plan, smaller than those of the underside of the block.

Preferably, the mechanical resistance of the sole is improved by integrating, during step a), a reinforcement with the visco-elastic material of the prefabricated plate, the rail rail support according to the invention then being characterized by 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 of gravel fixed to the sole, which facilitates the implementation of step a) according to a method consisting in fixing the gravel to the plate by partially integrating them into the visco-elastic material, which means that the support according to the invention is then characterized in that the gravel fixed 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 outside of it a projection of a height of the order of 50% to 95% of their height, measured perpendicular to the gravel face, so well that the gravel attached to the sole are integrated into the visco-elastic material thereof over a height of the order of 5% to 50% of their height, measured perpendicular to the underside of the block.

In such a case, in fact, the plate is advantageously prefabricated, during step a), by melting, forming and solidifying the visco-elastic material, chosen to be hot-melt, and the gravel is partially integrated into the visco-material. elastic 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 reinforcement, and if this reinforcement defines meshes of dimensions smaller than the grain size of the gravel of the prefabricated plate, this reinforcement prevents the gravel thus sown between the forming and the solidification of the visco-elastic material passing through this material until reaching the face of the prefabricated plate intended to constitute the face of 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 fixed to the sole, have the same nature and the same particle size as those of concrete, and leave spaces between them whose dimensions correspond to the maximum to their particle size, which on the one hand facilitates the insertion of the gravel of the prefabricated plate between those of the concrete intended to constitute the block during the pouring of this concrete and on the other hand ensures a homogeneity of the distribution of the gravel in concrete up to the immediate vicinity of the base.

In this respect, moreover, the gravel of the prefabricated plate, that is to say the gravel fixed to the sole, cover from 80% to 95% of the gravel face of the prefabricated plate, that is to say say more of the underside 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 the manufacture of a railway sleeper formed from a single block of prestressed reinforced concrete, a person skilled in the art will readily understand that the present invention also applies to the manufacture any other rail support comprising at least one concrete block, namely in particular the bi-block sleepers, comprising two reinforced concrete blocks connected by a spacer, the supports for the track equipment, the blocks intended to receive a rail individually , and it will bring to the provisions which will be described the modifications necessary in each case, without departing from the scope of the present invention.

Referring first to Figures 1 and 2, it will be recalled that a one-piece cross member 1, made of prestressed reinforced concrete, has the general shape of a block 2 of concrete, elongated in a longitudinal direction 3 perpendicular to the rail 4 to be supported . If we refer to a laying position, in which the cross member 1 is partially embedded in ballast 5, the block 2 is delimited by a flat bottom face 6, longitudinal, parallel to the rolling plane 7 of the rails, this face lower 6 being embedded in the ballast 5 and resting thereon, flat, by means of a sole 8 of a visco-elastic material chosen for example in accordance with the teachings of EP-A-0 465 390, and an upper face 9 which is essentially flat and parallel to the lower face 6 in the example illustrated but could have other conformations, and receives the two rails 4 directly or, as illustrated, by means of saddles 10, with elastic fixing of the rails 4 by means 11 which are 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 mutually from the first to the second, so as to communicate to block 2 a cross section in the form of an isosceles trapezoid, and by two transverse end faces 13 also plane, also connecting the lower face 6 to the upper face 9 and connecting in in addition to each other the two longitudinal faces 12, these two faces 13 being approximately transverse and converging mutually from the lower face 6 towards the lower face 9 so that when it is seen in section through a longitudinal plane perpendicular to these faces 6 and 9 , the crosspiece also has a section essentially in the form of an isosceles trapezoid. This mutual convergence, upwards, on the one hand of the longitudinal faces 12 and on the other hand of the 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 further, and has the advantage of causing it to be anchored in the ballast 5, which drowns the faces 12 and 13 over most of their height, as appears from the examination of Figures 1 and 2. However, it is understood that other shapes could be chosen without departing from the scope of the present invention, the only one having, with regard to it, 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 has, in contact, flat with the lower face 6 of the block 2, a planar upper face 14 integral with this lower face 6 while it presents towards the bottom, that is to say in contact with the ballast 5, a lower face 15 also planar, parallel to the upper face 14 and sufficiently close to the latter so 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 of the order of 4 mm, these figures being given only by way of nonlimiting example. The two faces 14 and 15 are connected to each other by an edge 16 which is perpendicular to them and gives them a rectangular shape which can be identical to that of the lower face 6 of the block 2, that is to say in particular have the same dimensions. that this lower face 6 so that the sole 8 completely covers the latter, in a manner known per se, or be approximately identical to that of the lower face 6, and more precisely have dimensions a few millimeters smaller than those of this lower face 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 the block 2 and the sole 8 in accordance with the present invention, as will appear below, and whose direct contact with the ballast 5 has little drawback insofar as this zone 17 is limited to the immediate proximity 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 the block 2, in the manufacture thereof, but a specific method of prefabrication, constituting an implementation mode The preferred embodiment of the present invention will now be described with reference to FIG. 3, with regard to the prefabrication process, and FIG. 4 with regard to the prefabricated plate obtained, intended to constitute the sole 8.

FIG. 3 shows that a plate 18 is initially produced having a lower face 19 and an upper face 20 that are plane, mutually parallel, separated by a thickness e corresponding to the thickness e of the sole 8 measured between its upper face 14 and its underside 15, with plan dimensions which may be those of the sole 8 to be produced, or even be much greater to correspond to the soles 8 of several crosspieces 1, in which case the plate 18 is cut at a time any preceding its integration, as a sole 8, to 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 a 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, by example woven so as to define mesh 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 frame 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 frame 22 as the layer 24, now secured to the layer 21 through the meshes 23 of the frame 22, form a projection on the face 20 of the plate 18, regularly distributed on this face 20 and leaving between them, on the latter, free spaces 28 whose dimensions correspond as much as possible to their particle size, which is also that of the gravel intended to enter the composition of the concrete constituting the block 2.

By way of nonlimiting example, using in particular as gravel 27 a silica-limestone crushed with sharp edges with a particle size of 3 mm / 10 mm, preferably 4 mm / 8 mm, in particular a crushed responding to the particle size analysis by sieving emerging from FIG. 11, which must be considered as integrated into the present description, good results have been obtained 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 the face 20, a projection of a height h of the order of 50% to 95% of their height H, also measured perpendicular to the gravelled face 20; in other words, the gravel 27 was integrated into the visco-elastic material of the plate 18 over a depth p, measured perpendicular to the gravel face 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 the layer 24, it -even 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 readily be understood by a person skilled in the art. For reasons of simplicity, the same reference numeral 18 will be kept thereafter to designate a plate produced directly to the dimensions of a determined sole 8 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 will now be described, with reference to FIGS. 6 to 10.

These operating conditions differ little from the usual operating conditions for manufacturing sleepers, so that they will only be described in broad outline, except with regard to the operations of placing and integrating the prefabricated plate 18.

In the nonlimiting example illustrated, in a manner known per se, a mold 29 is used for molding the reinforced concrete constituting the block 2 which is detachably hung on a vibrating table 30, in a position of use which will serve as a reference to the brief description, 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 which these flank 33 and end 34 faces delimit a filling opening 36 fully open, rectangular like the underside 6 of the block 2 to be produced and having dimensions slightly greater 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 end faces 34 of the prestressing frames 37 of the block 2 in compression, and may have various arrangements, in particular at the level of the bottom 32, to optionally receive members to be incorporated into the concrete of block 2 with a view to fixing the saddles 10, in the form of inserted dowels or studs, in a manner not illustrated but well known to a person skilled in the art.

The reinforcements 37 having been put in tension inside the cavity 31 and the other reinforcements of the block 2 to be produced having also been placed in this cavity 31, as well as any member to be integrated into the concrete in particular for fixing the saddles 10, the concrete 38 intended to constitute the block 2 is poured into the cavity 31, by vibrating the vibrating table 30 under the usual operating conditions, as illustrated in FIG. 6.

The cavity 31 is thus substantially filled with concrete 38 which, at the end of this filling, presents upwards a free surface 39 approximately flat and approximately level with the upper face 35 of the mold 29, in the filling opening 36 , as can be seen in FIG. 7 which illustrates a next phase in the production of the block 2. This phase consists in tamping with the free surface 39 in particular to make it smooth and flat, that is to say giving it the conformation of the lower face 6 of block 2 which it is intended to constitute. The concrete 38, inside the cavity 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 the concrete 38, a rise in milt at the level of the surface 39, this possible rise in milt being used according to one of the preferred embodiments of the present invention for ensuring the subsequent anchoring of the plate 18 by its gravelled face 20.

In known manner, the tamping is accompanied by vibrations communicated by the vibrating table 30 and is carried out by means of a jack 40 having the general shape of a rigid plate having a flat lower face 41 of tamping, horizontal and having a shape in rectangular plan, corresponding to that of the face 6 to be produced, so that it can be moved towards the inside of the imprint 31 by applying pressure to the face 39 until it occupies relative to the bottom 32 of the imprint 31 a position identical to that of the lower face 6 of the block 2 with respect to the upper face 9 thereof. The 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 diagrammatically by a double vertical arrow 43, of lifting relative to the mold 29, to release the filling opening 36, and the descent towards this mold 29, that is to say towards the inside of the cavity 31, in order to compact the free surface 39 of the concrete 38 with the application of pressure to this one.

A next step, illustrated in FIG. 8, is characteristic of the implementation of the present invention and consists in depositing on the free, grated surface 39 of the concrete 38 the plate 18, the gravel face 20 of which is turned towards the bottom so that this gravelled face 20 essentially covers the free surface 39 of the concrete 38, in a position substantially identical to that which the sole 8 must occupy with respect to the underside 6 of the block 2. Naturally, this deposition takes place while the tamping plate 40 is lifted.

If the quantity of laitance available on the surface 39, after the tamping illustrated in FIG. 7, is insufficient to carry out the rest of the process, under conditions which will be described later, the step illustrated in FIG. 7 can be entered and the step illustrated in FIG. 8 effecting on the free surface 39 of the concrete an addition of an additional material constituting the latter, namely in particular water, pure cement or cement added with sand, preferably without adding gravel. Naturally, the material thus provided, comparable to a supplement of laitance, is in the fluid state, in the same way as the concrete 38 filling the imprint 31.

Then, as shown in FIG. 9, the tamping plate 40 is lowered towards the imprint 31 so that the face 41 of this tamping plate 40 rests flat on the face 19, then turned upwards, of the plate 18 itself bearing downwards, by its gravelled face 20, on the free surface 39 of the concrete 38. A downward pressure is thus applied to the gravelled plate 18, by means of the tamping plate 40 , by vibrating the mold 29 by means of the vibrating table 30, under conditions identical to those which gave rise to a possible rise in milt during the tamping described with reference to FIG. 7, so as to drive in the gravel 27 of the gravelled 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 are themselves applied under pressure to the concrete 38, which completely coats the gravel part 27 forming a projection relative to the gravelled face 20 of the plate 18. Taking into account that the gravel 27 has a particle size identical to that of the concrete gravel 38, on the one hand, and delimit between them free spaces 28 having dimensions corresponding as much as possible to this particle size, on the other hand, gravel 44 of the concrete 38 is inserted in the free spaces 28 between the gravel 27 during this phase of penetration of the latter into the concrete 38, as shown in the figure 5 illustrating the finished cross-member 1, in the position of use, so that the gravel 27 is embedded in concrete 38 under the same conditions as the 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 the plate 18. It is understood, however, that the concrete 38 may also contain gravel with a grain size greater than that of gravel 44, in a manner known per se. Depending on the case, the continuity between the gravel 44 and 27 is ensured by the sole laitance raised during tamping illustrated in FIG. 7, or by the filler material deposited on the free surface 39 between the steps illustrated in FIGS. 7 and 8 in the event that the quantity of laitance thus available is insufficient ; a possible excess of laitance or filler material can be evacuated upward around the plate 18, taking account of the aforementioned dimensioning of the latter.

It will be noted that the preferred choice, for the plate 18 intended to 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 the concrete 38 inside the cavity 31, also facilitates the evacuation of the air which could tend to remain trapped between the plate 18 and the concrete 38, that is to say allows to obtain a as intimate contact as possible between the concrete 38, on the one hand, the gravel 27 and, through 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 by driving the gravelled plate 18 into the fresh concrete 38 using the above-mentioned 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 set sufficiently, the block 40 is lifted and the vibration stopped, and the mold 29 is detached from the vibrating table 30 to convey it to an intermediate storage area or, as illustrated in the figure 10, towards an oven to authorize or cause the setting of the concrete 38. During this setting, as shown in FIG. 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 this support 45 by means of the gravelled plate 18 and contributes, by its own weight, to preserve the integration of the gravel 27 thereof into the concrete 38; however, it would not be departing from the scope of the present invention to leave the face 35 of the molds facing upwards during setting of the concrete 38.

After the time necessary for it to set completely, under conditions identical to the usual conditions, the molds 37 are released from the mold and released, which create a prestress. compression in the concrete 38, it being understood that the demoulding could also be carried out before the setting is complete; a cross member 1 is thus obtained according to the invention, in particular the lower face 6 of which is constituted by the surface 39, initially free, of the concrete 38 now constituting the block 2 and the sole 8 of which is constituted by the plate 18, the gravelled face 20 constitutes the upper face 14 and the other face 19 of which constitutes the lower face 15. The gravel 27, embedded both in the visco-elastic material now constituting the sole 8 and in the concrete 38 now constituting the block 2, provide a regularly distributed connection between the sole 8 and the block 2, in a particularly effective manner, by covering the same proportion of the lower face 6 of the block 2 as of the upper face 14 of the sole 8, namely from the '' from 80% to 95% in the preferred implementation example indicated above.

Naturally, a person skilled in the art will readily understand that not only the figures indicated, but also the method adopted for the molding of the concrete 38 and the integration of the gravel 27 from the plate 18 therein could be modified to a large extent without this goes beyond the scope of the present invention. In particular, provision could be made for the molding imprint 31 to be shaped so as to carry out the molding of the crosspiece not in an inverted position thereof but in another position, in which case it could be necessary to arrange the plate 18 in this footprint 31 before pouring the concrete 38 therein, the gravelled plate 18 being naturally placed in the zone of the footprint 31 intended to produce the lower face 6 of the block 2 of concrete and having its gravelled face 20 towards the inside of imprint 31.

Claims (26)

Method for manufacturing a rail support (4) for a railway, such as a cross-member (1), comprising at least one block (2) of concrete (38) having in particular an upper face (9) intended to receive at least one rail (4) and a lower face (6) intended to ensure the support of the block (2) on a substrate (5), such as a ballast (5), and a sole (8) of visco material elastic resiliently covering this lower face (6) and intended to serve as a support intermediary between the block (2) and the substrate (5), said method comprising the succession of steps consisting in: a) prefabricating a plate (18) of visco-elastic material, to the dimensions of the sole (8) to be produced, b) manufacturing the block (2) by molding concrete (38) in an imprint (31) by integrating the prefabricated plate (18) therein to constitute the sole (8), and c) authorize or cause the setting of the concrete (38) then unmold the block (2), solidly supporting the sole, characterized in that: - During step a), gravel (27) similar to that of concrete (38) of such type is fixed to one face (20) of the plate (18), intended to be turned towards the block (2) so that these chippings (27) form a projection on the face (20) thus gravelled and are regularly distributed thereon, and - during step b), the prefabricated plate (18) is placed, relative to the 'imprint (31), so that the gravel face (20) coincides with an area (36) of the imprint (31) corresponding to the underside (6) of the block (2) and is turned inward of the imprint (31), and that the gravel (27) of the gravel face (2) thus integrate with the concrete (38). Method according to claim 1, characterized in that said zone (36) of the imprint (31) is open and turned upwards during step b), and in that the step is carried out b) by first filling the cavity (31) with concrete (38) to form the underside (6) of the block by the free surface (39) of the concrete (38) and then applying thereto, before the setting of the concrete (38), the gravel face (20) of the prefabricated plate (18) under operating conditions capable of causing the integration of the gravel (27) of the gravel face (20) in the concrete (38). Method according to claim 2, characterized in that the free surface (39) of the concrete is smoothed before applying to it the gravelled face (20) of the prefabricated plate (18). Method according to any one of claims 2 and 3, characterized in that the concrete (38) is subjected to conditions, in particular of pressure and, preferably, of vibration having the effect of causing a rise in laitance before d '' apply the gravelled face (20) of the prefabricated plate (18) on its free surface (39), and in that the graveled face (20) of the prefabricated plate (18) is then applied to the free face (39 ) concrete (38) under operating conditions, in particular of pressure and, preferably, of vibration, such that this results in flooding of the gravel (27) of the gravel face (20) in the laitance and filling, by the latter, of the intermediate space between the free surface (39) of the concrete (38) and the prefabricated plate (18) without any other material for this purpose. Method according to either of Claims 2 and 3, characterized in that, between the filling of the concrete cavity (31) (38) and the application of the gravelled face (20) of the prefabricated plate (18) on the free surface (39) of the concrete (38), there is added thereto a material constituting the concrete, in the fluid state, chosen from a group comprising in particular water, pure cement and cement added with sand, and in that the graveled face (20) of the prefabricated plate (18) is then applied to the free surface (39) of the concrete (38) under operating conditions, in particular pressure and, preferably of vibration, as it results from the integration of the gravel (27) of the gravel face (20) of the prefabricated plate (18) with the filler material and the filling, by the latter, of the space interlayer between the free surface (39) of the concrete (38) and the prefabricated plate (18). Method according to any one of Claims 1 to 5, characterized in that the prefabricated plate (18) has dimensions, in plan, smaller than those of the free surface (39) of the concrete (38). Method according to any one of Claims 1 to 6, characterized in that, during step a), an armature (22) is integrated into the visco-elastic material of the prefabricated plate (18). Method according to claim 7, characterized in that the reinforcement (22) defines meshes (23) of dimensions smaller than the particle size of the gravel (27) of the prefabricated plate (18). 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 partially integrating them into the visco-elastic material. Method according to claim 9, characterized in that, during step a), the plate (18) is prefabricated by melting, forming and solidifying the visco-elastic material, chosen to be hot-melt, and in that it is partially integrated the chippings (27) in the visco-elastic material by sowing them thereon between forming and solidification. A method according to any one of claims 9 and 10, characterized in that the gravel (27) of the prefabricated plate (18) form outside thereof a projection with a height (h) of the order of 50% at 95% of their height (H), measured perpendicular to the gravel face. Method according to any one of Claims 1 to 11, characterized in that the gravel (27) of the prefabricated plate (18) has the same nature and the same particle size as that of the concrete (38). Method according to any one of Claims 1 to 12, characterized in that the gravel (27) of the prefabricated plate (18) leaves spaces (28) between them, the dimensions of which correspond as much as possible to their particle size. Method according to any one of Claims 1 to 13, characterized in that the gravel (27) of the prefabricated plate (18) covers from 80% to 95% of the gravel face (20). A method according to any one of claims 1 to 14, characterized in that the gravel (27) of the prefabricated plate (18) is a crushed with sharp edges. Method according to any one of Claims 1 to 15, characterized in that the gravel (27) of the prefabricated plate (18) has a particle size of the order of 3 mm / 10 mm, preferably 4mm / 8mm. Railway rail support, such as a sleeper (1), comprising at least one block (2) of concrete (38) having in particular an upper face (9) intended to receive at least one rail (4) and a lower face (6) intended to ensure the support of the block (2) on a substrate (5), such as a ballast (5), and a sole (8) of visco-elastic material integrally covering this lower face (6 ) and intended to serve as a support intermediate between the block (2) and the substrate (5), characterized in that gravel (27) of the concrete (38) are fixed to one face (14) of the sole ( 8) facing the lower face (6) of the block (2), in a regularly distributed manner. Support according to claim 17, characterized in that the sole (8) has dimensions, in plan, smaller than those of the lower face (6) of the block (2). Support according to either of Claims 17 and 18, characterized in that the visco-elastic material of the sole (8) includes a frame (22). Support according to claim 19, characterized in that the frame (22) defines meshes (23) of dimensions smaller than the particle size of the gravel (27) fixed to the sole (8). Support according to any one of claims 17 to 20, characterized in that the gravel (27) fixed to the sole (8) form a projection outside the underside (6) of the block (2) and are partially integrated into the material visco-elastic sole (8). Support according to claim 21, characterized in that the gravel (27) fixed to the sole (8) are integrated into the visco-elastic material thereof over a depth (p) of the order of 5% to 50% of their height (H), measured perpendicular to the underside (6) of the block (2). Support according to any one of claims 17 to 22, characterized in that the gravel (27) fixed to the sole (8) have the same nature and the same particle size as the other gravel (44) of the concrete (38). Support according to any one of Claims 17 to 23, characterized in that the gravel (27) fixed to the sole (8) covers 80% to 95% of the lower face (6) of the block (2). Support according to any one of claims 17 to 24, characterized in that the gravel (27) fixed to the sole (8) is a crushed with sharp edges. Support according to any one of Claims 17 to 25, characterized in that the gravel (27) fixed to the sole (8) has a particle size of the order of 3 mm / 10 mm, preferably 4mm / 8mm.

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