EP3268195A1

EP3268195A1 - Method for moulding tubular elements in a material comprising cement, and pile thus produced

Info

Publication number: EP3268195A1
Application number: EP16712283.7A
Authority: EP
Inventors: Yves Brugeaud
Original assignee: Conseil Services Investissements
Current assignee: Conseil Services Investissements
Priority date: 2015-03-12
Filing date: 2016-03-11
Publication date: 2018-01-17
Also published as: WO2016142540A1; FR3033514A1; US20180071953A1; FR3033514B1

Abstract

The invention relates to a method for moulding a part (100), comprising the following steps: placing at least one prestressing device in a first element; placing the first element (20, 60) such that it faces a second element (1); prestressing of the at least one prestressing device; introducing ultra-high performance fibre-reinforced concrete (51) into the receiving space; controlling a progressive modification of one of the elements (20); and demoulding the tubular element (20).

Description

PROCESS FOR MOLDING TUBULAR ELEMENTS IN MATERIAL COMPRISING CEMENT AND PIEU THUS OBTAINED

FIELD OF THE INVENTION

The present invention relates to the field of the manufacture of elements made of material comprising cement and more particularly the molding of tubular elements in Fibré Concrete with Ultra High Performance (UHPC).

BACKGROUND OF THE INVENTION

It is known to produce tubular elements of concrete such as ducts or nozzles by molding. Conventionally, a cylindrical mold of vertical axis is placed around a tubular reinforcement cage and a twist is introduced into the interior space delimited by the reinforcement cage. The auger has an outer diameter substantially corresponding to the desired inner diameter for the tubular member and is located at the lower end of the mold. Concrete is then poured gravitarily into the mold while the auger is rotated and raised along the axis of the mold. The combined rotational and translational movements of the auger project the concrete through the reinforcement cage against the inner wall of the mold and shape the inner wall of the tubular member. Generally, the spin performs a single round trip along the vertical axis before being removed from the mold. Once the concrete setting is sufficient, the tubular element is demolded and is subjected to a drying phase.

Such a method performs a centrifugation of the constituents of the concrete, which, more particularly in the case of UHPC, causes a segregation of the constituents and therefore a heterogeneous distribution of the components in the concrete. As a result, the element cl -L. Ώ. S 1 -C Sc¾13 € ~ S € 5 cl € S j O ^ p 1 Έ51 € 2 SC * CLI! ^"1CJU. € SS" t € 5 S lower than it should have in theory.

Alternatively, and for elements of strong diameters, a rigid inner core is placed in the mold and defines the inner wall of a tubular casting space. Concrete is introduced gravitarily and vibrated into the tubular space of casting. Once the concrete setting is sufficient, the outer mold is deposited, and the inner core is removed from the tubular member. Such a method of manufacture requires providing a contact surface of the core with the inner wall of the rigorously smooth tubular element and / or a suitable draft angle. Such an embodiment is unsuitable for achievements in UHPC because this material has significant withdrawals. Indeed, a withdrawal of the UHPC around a rigid core will inevitably cause the cracking of the tubular element and a deterioration of the element during the removal of the core. existing processes molding tubular elements in UHPCB and in particular elements of great length and reduced outside diameter.

When building foundations for civil engineering works, such as crossing bridges, it is known to beat piles or micropiles in order to be able to rely on a ground by the effect of peak or friction. The implementation of piles generally requires threshing means and / or drilling. The piles set up can be prefabricated or cast on site. The piling of prefabricated piles requires the handling of massive piles, so the use of lifting gear in addition to threshing machines. There are also injected drilled piles that allow the injection of a cementitious material into the soil. A cylindrical cavity is first drilled in the ground and then a tubular sheath is made against the wall of the cavity with a grout. sheath. A sleeve tube is placed in the sheath and the injection material is injected at different points of the sleeve tube. Under the pressure of the injection material, the sheath fractures (it is said to "slap") and allows the injection material to diff er into the surrounding soil, thereby stabilizing it. This technique is particularly advantageous, but requires having a drill and qualified personnel for its use. All of these constraints prevent the development of crossings in isolated areas, particularly in developing countries for which the civil engineering machinery fleet is small, whereas it is in these countries that the need for traffic and crossing infrastructure is the most important.

OBJECT OF THE INVENTION

The object of the invention is to produce tubular elements in UHPC by molding, particularly in long lengths.

SUMMARY OF THE INVENTION

For this purpose, there is provided, according to the invention, a method of molding a piece of material comprising cement, comprising the following steps:

- Installation of at least one prestressing device in a first element

placing a first element opposite a second element so that an external wall of one of the elements delimits, with an internal wall of the other element, a receiving volume, the shape of a elements being progressively modifiable on order;

- introduction of the material comprising cement of

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prestressing the at least one device prestressing by applying a tensioning force on the latter;

control of a progressive modification of the shape of one of the elements as and when the material containing cement is taken;

- demolding of the part.

Advantageously, the molding process is applied to the molding of a tubular part made of material comprising cement, and comprises the following steps:

- Establishment of a core in a cylindrical mold so that the outer wall of the core defines with the inner wall of the mold a tubular receiving volume, the shape of the core being modifiable progressively on command;

introduction of the material comprising cement so as to fill the tubular receiving volume;

control of a progressive modification of the shape of the core as the cement material is taken until a core shape is obtained enabling it to be extracted from the tubular element after at least partial seizing of the material comprising cement;

- removal of the nucleus;

- Release of the tubular part.

It is then possible to easily mold tubular pieces of great length without having to provide draft angles which would lead, for small diameters and / or elements having a closed end, to a strongly flared shape. Deformation of the core accompanies the removal of the material containing cement and reduces the risk of cracking the material. The core then absorbs the shrinkage of the material during curing in the mold. Removal of the core is easy and without risk to the integrity of the molded tubular element.

Advantageously, the material comprising cement is ultra high performance fiber reinforced concrete (UHPC).

Alternatively, the material comprising cement is mortar. According to a particular embodiment, the core is manufactured at least partially wax.

The wax is a material that can be reused for a new molding operation, non-toxic and whose control of the deformation is easy. In addition, wax is an advantageous material for absorbing withdrawal of UHPC.

Advantageously, the outer surface of the core is shaped to print a rough surface condition and / or cavities on the inner surface of the tubular pile.

This improves the adhesion of a possible second phase concrete which has flowed inside the tubular element.

The invention also relates to a tubular pile e ultra high performance fiber concrete molded according to this method.

The invention also relates to a kernel of modifiable shape progressively on command for the implementation of the method.

BRIEF DESCRIPTION OF THE DRAWINGS

Reference will be made to the appended drawings among which:

- Figure 1 is a schematic perspective view of a longitudinal section of a pile according to a first embodiment of the invention;

- Figure 2 is. a schematic perspective view of a longitudinal section of a pile according to a second embodiment of the invention; Figure 3 is a schematic perspective view of a longitudinal section of a pile according to a sixth embodiment of the method of the invention;

Figure 4 is an exploded perspective view of a mold according to the invention;

Figure 5 is a side view of a core according to a first embodiment of the invention;

Figure 6 is a sectional view along the VI-VI cutting plane of the core of Figure 5;

Figures 7a to 7f are schematic views in longitudinal section of the different steps of a first embodiment of the method according to the invention;

Figure 8 is a schematic perspective view of a core according to a second embodiment of the invention;

Figures 9a to 9f are schematic views in longitudinal section of the different steps of a second embodiment of the method according to the invention;

Figure 10 is a sectional view along the X-X section plane of Figure 9b;

11 is a schematic jp € iX ^"IS € ^2" t 1 ^{^"V"} î € ï € The U.3TX C- 011 Ç2JC ^"tt ^ 5 S € S1G Γ1 ^IU!" 11 3 ~ S 1. ZTI ^ embodiment of the invention;

Figures 12 to 12. f are schematic views in longitudinal section of the different steps of a third embodiment of the method according to the invention;

Figure 13 is a schematic longitudinal sectional view of a further step of the third embodiment of the method according to the invention; Figure 14 is a schematic perspective view of a core and its associated mold according to a fourth embodiment of the invention;

Figures 15 to 15. f are schematic views in longitudinal section of the various steps of a fourth embodiment of the method according to the invention;

Figure 16 is a schematic longitudinal sectional view of a previous step of the fourth embodiment of the method according to the invention;

Figure 17 is a schematic perspective view of a fifth embodiment of a device according to the invention;

Figure 18 is a perspective detail view of Figure 17;

Figures 19a to 19e are schematic longitudinal sectional views of the various steps of the embodiment of the method according to the invention corresponding to the device of Figure 16;

Figures 20a to 20e are schematic views in longitudinal section of the various steps of a fourth embodiment of the method according to the invention;

Figures 21a to 21h are schematic views in longitudinal section of the different steps of a fifth embodiment of the method according to the invention;

Figure 22 is a longitudinal sectional view of a pile according to the embodiment of Figures 21a to 21h;

FIG. 23 is a detail view in longitudinal section of the end of the pile of the Figure 23;

FIG. 24 is a schematic perspective view of a core for a sixth embodiment of the method according to the invention;

- Figure 25 is a detailed longitudinal half-sectional view of a pile according to the sixth embodiment of the method according to the invention;

FIG. 26 is identical to that of FIG. 25 when the pile is injected;

- Figure 27 is a schematic view of a pile assembled according to a seventh embodiment of the invention.

Fig. 28 is a schematic view of an eighth embodiment of a pile according to the invention;

- Figure 29 is a longitudinal sectional view of a bend according to a ninth embodiment of the invention;

- Figure 30 is a longitudinal sectional view of a core according to a ninth embodiment of the invention;

FIGS. 31a to 31g are diagrammatic views in longitudinal section of the various steps of the ninth embodiment of the method according to

The invention, DETAILED DESCRIPTION OF THE INVENTION

With reference to FIG. 1, the tubular element to be manufactured is a pile of UHPCF, generally designated at 100, extending along a longitudinal axis (X). The pile 100 comprises an outer wall 101 and an inner wall 102. The upper end 103 of the pile 100 is open and the lower end 104 has a tip 105. The inner wall 102 defines an interior volume 106 of substantially cylindrical shape and circular striations 108. The pile 100 here has an outside diameter of 200 millimeters.

According to a second embodiment shown in FIG. 2, the pile 100 may comprise annular walls 110 extending radially in the volume 106 to divide it into several compartments 111.

Finally, according to a particular embodiment shown in Figure 3, the pile 400 comprises four radial channels 486 connecting the inner volume 406 of the pile 400 and an outer peripheral groove 487 in which extends a polymer ring 488.

A first embodiment of a method of molding a pile 100 is described with reference to FIGS. 3 to 6. This first embodiment of the method according to the invention implements a mold 1 and a core 20.

Referring to Figure 4, the mold 1 is a cylindrical mold extending along a longitudinal axis (X) and separated into two half-mou1 5s 2 € € 5 ^"t 3 sΘl.on a plane containing the longitudinal axis ( X) The half-molds 2 and 3 are provided with the means of being secured to one another, here in the form of notched tabs 4 integral with the half-mold 2 and intended to cooperate with jamming cleats 5 integral with the half-mold 3. The inner wall 6.1 of the mold 1 formed by the assembly of the two half-molds 2 and 3 defines a volume 6 comprising a cylindrical portion 7 open at the upper end 8 of the mold 1 and a conical portion 9 of which the tip 10 closes the volume 6 at the lower end 11 of the mold 1.

With reference to FIG. 5, the core 20 comprises a cylindrical envelope 21 of flexible silicone extending along a longitudinal axis 22. The outside of the envelope 21 defines an outer wall 21.1 of the core 20. A first end 23 of the 21 is closed by a substantially spherical cap 24 while that the other end 25 is closed by a plug 26. The outer wall 21.1 comprises conical protrusions 27 of wedge positioning the core 20 projecting in directions substantially perpendicular to the longitudinal axis 22. The plug 26 is crossed by an inlet end 28 and an outlet end 29 of a conduit 30 for circulating a U-shaped refrigerant 31 and extending along the longitudinal axis 22. The plug 26 is also traversed by one end 32 of a conduit 33 for filling and draining water from the envelope 21. According to a preferred embodiment, the outer wall 21.1 has a rough surface state as well as circular grooves 34 on a portion of about 300 millimeters measured from the end 25.

According to a preliminary step of the first embodiment of the molding process, the envelope 21 is placed in a chamber 40 of a mold 41 whose inner wall has a shape identical to the desired outer shape of the core 20 (Figure 7a). Once the envelope 21 e place, a water supply pipe is connected to the end 32 of the conduit 33. The casing 21 is filled with water and then comes to press against the inner wall of the chamber 40 When it is completely filled with water, the envelope 21 takes the form of the inside wall of the chamber 40. A refrigerant 31 is then circulated in the conduit 30 and solidifies the water in the envelope 21 turning it into ice. The envelope 21 thus shaped is then demolded, for example by separating the mold 41 into two half-molds. A core 20 is then obtained having a solidified shell 21 having a defined shape, namely a cylinder provided with conical protuberances.

The core 20 is then put in place in the mold 1 so that the outer wall 21.1 of the core 20 defines with the inner wall 6.1 of the mold 1 a receiving volume 50 (Figures 7b and 7c). The distal ends of the conical protrusions 27 of the core 20 5 come into contact with the inner wall 6.1 of the mold 1 and realize the centering core 20 in the mold 1 et1ï ^"lS 1 CU. UL3D. Î € d1minu.t LC3Γ 1 ^~ 10C »3.11 S € 5 € 5 C € 5j) 3.1 SS UJ-iC2 j 3.JCCD.1 d € 5

UHPCF to facilitate the breakdown of the wall in case of injection of the pile. At the next step,

10 injection of BFUP 51 so as to fill the reception volume 50 (FIG. 7d). As and when the UHPC 51 is taken, a hot heat-transfer fluid 52 is circulated in the conduit 30. Under the effect of the heat of the fluid 52, the ice contained in the envelope

21 liquefies and the meltwater is discharged through the conduit 33. This allows to control a progressive change in the shape of the core 20 that accompanies the withdrawal of the UHPC 51. Once the majority of the ice contained in the the envelope 21 has been liquefied and

20 evacuated, we finally get a shape of the core 20 for its extraction from the inside of the molded pile 100. The core 20 is then removed (Figure 7e) and the two half-molds 2 and 3 are separated, allowing the demolding of the pile 100 (FIG. 7f). We then obtain a pile 100 in

25 UHPC whose inner wall 102 has a surface state o at its upper part, resulting from the respective printing of the surface condition, and the circular grooves 34 of the outer wall 21.1 of the core 20.

The inner wall 102 of the pile also has conical cavities 109 resulting from the printing of the conical protuberances 27 for centering the core 20.

Elements identical or similar to those previously described will bear a numerical reference

* 3i ^* i ^~ C3 -L.ci tL. ^ U, i c_ € ¾mn r ^ ~ L i¾-e. ~ 3. cis latter -jt ^ 3 ^"-L" t -i- Din 0- ^ 1 _* -i. IL. "You are here! second, third, fourth, fifth, sixth, seventh and eighth embodiments of the molding method according to the invention of a UHPC pile.

The second embodiment of the method involves the mold 1 and a core 60 made from wax elements. With reference to FIG. 8, the core 60 comprises three cylindrical wax elements: a tip element 61, an intermediate element 62 and an end element 63 interconnected by wax shafts 64 and 65 cooperating with cavities axial cylindrical 61.1, 62.1, 62.2, and 63.1 in the elements 61, 62 and 63. Each element 61, 62 and 63 comprises conical protuberances 27 and a rough surface condition. The end member 63 also includes circular ridges 34. Thus, the outer wall 60.1 of the core 60 is provided with a rough surface condition and circular ridges 34.

The core 60 is first placed in the mold 1 so that its outer wall 60.1 delimits with the inner wall 6.1 of the mold 1 a receiving volume 50 (Figures 9a and 9b). As shown in FIG. 9, it may be advantageous to previously dispose on the core 60 (for example by gluing) centering wedges 70 of substantially conical shape so as to center the core 60 in the mold 1. These centering wedges 70 may advantageously be made of silicone. In the next step, BFUP 51 is injected so as to fill the receiving volume 50 (FIG. 9c). As and when the UFUP 51 is taken, the core 60 is heated, here by injection of hot water or of relaxed steam on and in the core for example by means of a cannula. Under the effect heat, the wax of the elements 61 to 65 softens and causes a gradual change in the shape of the core 60 that accompanies the withdrawal of the BFUP 51 (figures 9d). Extraction of the core 60 from the inside of the molded pile 100 is performed when the elements 61 to 65 have fully melted (FIG. 9e). The two half-molds 2 and 3 are separated and the pile 100 is demolded (FIG. 9f). A pile 100 made of UHPCF is then obtained, the inner wall 102 of which has a rough surface state, and the circular ones 108 at its upper part, resulting from the respective impression of the surface state, and the circular striations 34 of the wall. outer 61.1 of the core 60.

According to a third embodiment, the method comprises the additional step of disposing a metal flange 80 at the inlet of the mold 1 prior to the introduction of the UHPC in the mold 1. El1 ^* 1 ΧΓ6 JL € 5 € 3Ω.C _* € 5 ci _Lcl f ~ LCJWX ^" IGi

a right cylinder portion 81, one end 82 of which comprises a radial annular portion 83. The portion 83 comprises three circular holes 83.1, 83.2 and 83.3 opening respectively on cylindrical sleeves 84.1, 84.2 and 84.3 whose end opposite to the portion 83 is closed. The sleeves 84.1 to 84.3 also contribute to securing the flange 80 with the UHPC and are adapted to receive cylindrical rods 85. The steps 12.a to 12.sub.f of the method according to this third embodiment are identical to the steps 9. a to 9. f of the second embodiment of the method. However, an additional step, shown in FIG. 13, consists in arranging a metal flange 80 at the entrance to the mold 1 prior to the introduction of the UHPC into the mold 1. The resulting BFUP 120 then comprises a flange 80 which allows to preserve the upper end 103 of the pile 120 during its threshing.

According to the fourth embodiment described with reference to FIGS. 14 and 15, the tip portion 61 core 60 is replaced by a portion 66 identical to the end portion 63 (Figure 14). The core 67 thus obtained is intended to be placed in a mold 68 similar to the mold 1 but whose conical portion 9 of the lower end 11 is replaced by a flat transverse portion 69. The steps 15a to 15. f of the method according to this Fourth embodiment correspond to steps 12.a to 12. f and 13 of the third embodiment of the method. However, an additional step, represented in FIG. 16, consists in arranging a metal flange 80 at the lower end 11 of the mold 1 prior to the introduction of the core 67 into the mold 1. The pile BFUP 130 thus obtained then comprises a first flange 80 in its lower part and a second eure.

The flanges 80 make it possible to protect the ends of the piles 120 and 130 when they are beaten and also allow the solidification of the upper end of a pile 120 or 130 with the lower end of a pile 130 by welding two flanges 80 adjacent.

The piles 100, 110 and 120 can be advantageously beaten in a ground and easily leveled when they arrive in refusal. This has an advantage over prefabricated beaten piles in terms of handling and implementation time. Indeed, the tubular piles 100 and 110 are lighter than the massive prefabricated piles and can be cut more easily. The piles 100 and 110 may also be placed in boreholes and subsequently receive a ferra bonding and / or grout cement or concrete second phase. Finally, these piles 100 and 110 can also be used to perform a ground injection. In the case of such a use, it will be possible to realize in the factory or on site peripheral holes. in the pile 100 or 110 if it is desired to use moderate power injection pumps and with higher power pumps, it will be possible to slam the pile to the right of the conical protuberances 27 because of the local sub-thickness of the pile 100 at this place.

According to a fourth particular embodiment detailed in FIGS. 17 and 18, the centering of the core 60 is made using three prestressing wires 90. The wires 90 are notched and of relatively small diameter here four millimeters in diameter. These wires 90 extend between two flanges 80 placed at the ends of the mold 1 and which receive the ends 91 of these wires in holes 92. As can be seen in FIG. 17, the core 60 comprises three semi-cylindrical longitudinal grooves 93 whose walls contact with at least a portion of the outer surface of the wires 90. Semicylindrical recesses 96 of diameter greater than that of the grooves 93 extend coaxially thereon over portions of length JL regularly distributed over the length of each groove 93. Additionally, the core 60 also makes recesses 97 corresponding to the volumes located vertically above the intermediate elements 62. These recesses are preferably located at 600 millimeters from each other and have a length 1 of 80 millimeters . Ideally, the recesses 96 have a diameter greater than twelve millimeters to the diameter of the wires 90.

The manufacture of a pile 130 according to the fourth embodiment will be described with reference to Figures 19a to 19e.

The ends 91 of the threads 90 are passed through holes 92 of a first flange 80 positioned at a first end of the half-mold 2 and 19a). The core 60 is presented to align the grooves 93 with the ends 91 of the wires 90. The core 60 is then slid between the cables 90, guided by them (Figure 19b). A second collar 80 is put in place at the second end of the half-mold 2 and the ends 91 of the wires 90 are passed through the holes 92 (FIG. 19c). The half-mold 3 is fixed on the half-mold 2 and the ends 91 of the wires 90 are stretched to effect a prestressing of the wires 90 (FIG. 19d). The core 60 is held in position between the wires 90 engaged in the grooves 93 and is then centered in the mold 1, delimiting the receiving volume 50. The casting steps of the UHPC and extraction of the core 60 are identical to those exposed. previously. The recesses 96 and 97 are filled with UHPC during casting and ensure both an anchorage and

(here, a minimum of six millimeters for the recesses 96) around the wires 90. Once the UHPCF is complete, the voltage applied to the ends 91 of the wires 90 is released and the pile 130 is demolded (FIG. 19e). The free ends 91 of the wires 90 can be used to handle the pile 130. This embodiment is also suitable for centering the soft shell core 20.

The fifth embodiment of the molding method according to the invention relates to the production of a tubular pile 300 and involves a core 360 made using a mold 341, according to a method shown in Figures 20a to 20d.

The core 360 comprises a metal tube 361, here a straight cylinder, on the inner side of which an electric heating cord 362 makes a spiral. The heating cord 362 is sized to generate 120 degrees centigrade. The core 360 also comprises, at its first end 363, a flange 364 made of polymer provided with a central orifice (FIG. 20a). Two metal half-shells 342a and 342b internally coated respectively with a half-jacket 343a and 343b of polymer are placed on either side of the tube 361 and secured around it (Figures 20b). Closure plates 365 and 366 close the ends of the mold 341 so as to define, together with the half-shells 342a and 342b, a tubular injector chamber 340 around the tube 361 (Figure 20c). A wax 366 in the liquid state (melted) is then injected into the chamber 340 so as to coat the tube 361. Once the wax 366 has cooled, the core 360 composed of the tube 361 coated with the wax layer 366 and comprising the flange 364 is demolded (Figures 20d and 20e). Operations for shaping the wax layer 366 by machining can be carried out so as to give it the desired profile. Preferably, 366 has a softening point of 75 to 115 degrees centigrade. More preferably, the wax 366 has a melting temperature greater than 115 degrees centigrade. The thickness of the wax layer 366 coating the core 360 is generally between five and fifty millimeters.

The manufacture of a pile 300 according to the fifth embodiment will be described with reference to FIGS. 21a to 21d.

A first wire 90 is placed in the half-mold 3 (Figure 21a) extending over the entire length thereof. The first wire 90 extends beyond the ends of the half-mold 2. The core 360 is then put in place opposite the half-mold 2 (Figure 21b). The second and third wires 90 are then put in place around the core 360 and the ends 91 of the wires 90 are passed through the holes 92 of a first flange 80 placed near the end 362 of the core 360 (Figure 21c). The half-mold 3 is presented facing the half-mold 2 and secured thereto, thereby defining a receiving volume 350 (Figure 2 here). A first abutment plate 311 (here a circular flange) including orifices 313 for passage of the extemities 91 of the wires 90 is bolted to a first end 1.1 of the mold 1 (FIG. 21e).

The mold 1 is then positioned vertically and filled with UHPCF by its second upper open end 1.2. A first thermocouple of UHPC 321 and a second thermocouple of wax 322 are respectively wax 366 of core 360 (FIG. 21f). The BFUP thermocouple 321 and the wax thermocouple 322 make it possible to measure the respective changes in the temperatures of the wax and the UHPC during the molding process. A second end plate 312, identical to the first end plate 311, is bolted to the second end 1.2 of the mold 1 and closes the mold 1 (Figure 21g).

The mold 1 also comprises means for prestressing the wires 90. These are in the form of two identical preloading mechanisms 309 and 310 (FIG. 21h). The preloading mechanism 309 comprises a plate 314 provided with three bores 315, two tapped holes 316 and 317 and locking bushes 318 of each wire 90. The locking bushes 318 bear on the face of the plate 311 opposite to that facing the abutment plate 312. Two CHC screws 319 and 320 are engaged in the tapped holes 316 and 317 so that their ends bear against the abutment plate 312. The preload mechanism 310 facing the cover plate 311 is identical to the prestress mechanism 309.

After casting and closing of the mold 1, the wires 90 are prestressed by applying a tensioning force using the prestressing mechanisms 309 and 310 by tightening the screws 319 and 320.

The measurement of the temperature of the UHPC using the thermocouple of BFUP 321 makes it possible to detect an increase in its temperature which marks the beginning of the hardening of the UHPC. A first temperature setpoint is sent to the heating cord 362 to establish a temperature of sixty degrees centigrade in the wax layer 366 of the core 360. Preferably, the first temperature set point is between fifty and seventy-five degrees centigrade. The wax thermocouple 322 may be used to establish a temperature control of the core 366 by coupling with the heating cord 362.

This set temperature brings the wax layer 366 of the core 360 to a temperature of sixty degrees Centigrade, which makes it possible to apply a heat treatment to the UHPC (here an acceleration of its hardening) without the geometry of the core 360 being modified under the effect of global wax 366 as the heat treatment temperature is below the softening temperature according to CD-ball method ^"t- rices ^~ _~ c iDC cIM DCE CD ^i" D 3 3 # ^ £ e preferably , the heat treatment of the UHPF has a duration of between 120 and 420 minutes.

The monitoring of the temperature evolution of the UHPF also makes it possible to anticipate the moment when the UHPC begins to withdraw. A second temperature setpoint sent to the heating cord 362 is then raised to a temperature of eighty-five degrees centigrade. Preferentially, the second temperature set is between seventy-five and one hundred degrees centigrade. This second temperature set brings the wax layer 366 of the core 360 to a temperature of eighty-five degrees centigrade, which causes a softening of the wax layer 366 of the core 360 because the value of the second temperature setpoint is greater than the softening temperature according to the ball and ring method of the wax 366. Preferably, the heat treatment of the UHPF has a duration of between 60 and 120 minutes. This softening of the wax 366 makes it possible that this does not prevent the removal of the UHPC during its hardening, which has the effect of limiting or even eliminating the cracking of the UHPC.

The monitoring of the temperature evolution of the UHPF also makes it possible to define the amount of heat to which the pile 300 is subjected during molding and thus to estimate the moment at which the pile 300 has sufficient strength to be prestressing.

A demolding step is then triggered.

In this step, a third temperature setpoint is sent to the heating cord 362 to raise the temperature to one hundred twenty degrees centigrade. Preferentially, the third set temperature is between one hundred and one hundred and twenty degrees centigrade.

This third temperature set brings the wax layer 366 of the core 360 to a temperature of one hundred and twenty degrees centigrade, which causes at least partial liquefaction of the wax layer 366 of the core 360 because the value of the third temperature setpoint is substantially equal to the liquefaction temperature according to the ball and ring method of the wax 366. The wax can be removed from the inside of the pile 300 to be collected for later use.

XJ G "S ^" V1 S 319 63 ^" t 320 SO ΓΊ ^" t 3.15 TS Ci65 SS € S € 3 € 5 S € 5 ^* t the application of the tensioning force of the wires 90 is canceled. We then obtain a prestressed pile 300. The pile 300 is then demolded by separating the two half-molds 2 and 3 and the end plates 311 and 312. The flange 364 is then removed from the pile 400 with a view to

As can be seen in FIGS. 22 and 23, the inside of the end 1.1 of the mold 1 is shaped in such a way that the first end 389 of the pile 300 has an outside diameter substantially equal to the inside diameter of the annular reservation left by the outer face of the flange 364 in the inner wall of the pile 300 at its second end 390. The pile 300 then has a first radial shoulder 391 and a second radial shoulder 392. A first and a second pile 300 can thus be assembled by fitting the first end of a first pile 300 into the second end of another identical pile. The threshing forces applied to the first pile are then transmitted to the second pile by a contact surface cor responding to the sum of the surfaces of the first shoulder 391 and the second shoulder 392, without the current section of the pile 300 is changed.

The use of the wires 90 makes it possible to establish a prestressing force in the pile 400 which greatly increases its resistance to bending with respect to a pile devoid of prestressing wires. The pile handling phases are often flat due to their long length, the preload of the pile 400 makes it possible to reduce the thickness of the UHPF wall of the pile up to ratios current thickness of the wall / total diameter of the pile. stake less than or equal to 0.2. This makes it possible to obtain lighter, longer and less expensive piles by reducing the share of UHPC in their manufacture. A sixth particular embodiment of a pile according to the invention relates to the realization of a tubular pile 400 in UHPC with integrated sleeve. With reference to FIG. 3, such a pile 400 comprises four radial connecting channels 486 between the internal volume 406 of the pile 400 and an outer peripheral groove 487 in

The molding method of the pile 400 is identical to that of the pile 300 but differs therefrom in that the core 360, shown in FIG. 24, comprises four protuberances 489.1, 489.2, 489.3 and 489.4 in wax 366 extending to 90 ° from each other in radial directions. The distal portion of each outgrowth 489.1, 489.2, 489.3 and 489.4 rejoins a ring 488, here in polymer. The outer diameter D _ext of the ring 488 is substantially smaller than the outside diameter of the receiving volume 350 of the mold 1. The molding method of the sixth embodiment of the invention is identical to the fifth embodiment of the invention but differs therefrom in that the prestressing threads 90 are put in place after placing the core 360 in the mold 1 so as to be able to be installed between the core 360 and the ring 488.

When pouring the UHPC into the mold 1, the protuberances 489.1 to 489.4 and the polymer ring 488 create reservations in the pile 400 so as to create radial connecting channels 486 between the inner volume 406 and an outer peripheral groove 487. After the core 361 and the protuberances 489.1 to 489.4 have been melted, the pile 400 is demolded and a pile 400 is obtained which comprises four radial channels 486 connecting the interior volume 406 of the pile which extends the ring. 488. The exterior face 488.1 of the ring is slightly set back from the outer face of the pile 400 which reduces the friction of the ring with the ground during the driving of the pile 400. According to a particular embodiment shown in FIG. 25, one of the ridges inside the ring can be glued to groove 487 by resin injection

Figure 26 shows the pile after it has been hammered into a soil 600. An injection material 601 is injected into the interior volume 406 of the pile 400. Under the effect of the pressure of the injection material 501 present in the channels, the unglued portion of the ring 488 is pushed outwardly from the pile 400 and allows the injection material 601 to diffuse into the ground 600, without requiring a "breakdown" of the pile 400 (FIG. ). When the pressure of the injector material decreases, the ring returns to its original shape and closes the channels 486, thus preventing a return of injected injected material 601 into the ground 600 to the interior volume 406. The configuration of FIG. the ring 488 and the pile 400 then perform the function of a sleeve tube of the prior art.

This results in a pile 400 in UHPC with integrated sleeve that can be beaten. Such a pile is economical to achieve because it does not require the implementation of metal pipe or PVC cuffs which are expensive devices. Such a stake makes it possible to emancipate myself. 1 X ~ l S ^" t 110 J1CCD K ~ cl CJ2 C" 1 € 3 S ^" t € 5ΓΊ. 01 ^* 1 € »d S € 3 S by threshing. Finally, the injection material can be injected at lower pressures because the pile 400 does not require "breakdown". It is then possible to implement smaller injection equipment, which results in additional savings in implementation. According to a detailed particular use in Figure 27 of a seventh embodiment of € 3 LS ^"t 1CD d € ΓΊ ^·" V ^"2 € Ί.t- 10ΓΊ f 1 ^S" t JOO SS 3- ~ L S € € 3 dl 3 XTlïb € 310 one or more piles 130 with a pile 120. The assembly is done by inserting cylindrical rods 85 through the holes 83.1 to 83.3 so that they are received in the sleeves 84.1 to 84.3 of the pile 120. The rods 85 are of a length such that they protrude from the upper end 103 of the pile 120. A pile 130 is then presented so that the bores 83.1 to 83.4 face the ends of the rods 85 received in the sleeves 84.1 to 84.3 the flange 80 of the pile 120. A relative translation of the piles 120 and 130 then makes it possible to engage the end of the rods 85 in the sleeves of the flange 80 situated in the lower part of the pile 130. The adjacent flanges 80 of the piles 120 and 130 are then assembled by welding. This method of assembly can be reproduced so as to make a pile of the desired length using prefabricated elements. Such an assembly can of course also be realized by involving one or more tubular pile elements 300.

It is also possible, as represented in FIG. 28 and according to an eighth embodiment of the invention, to combine one or more piles 130, 300 or 400 with a tip element 94 made entirely of UHPC and provided with a flange 80 The connection of the tip member 94 to the pile 130 is made by means of the cylindrical rods 85 and the flanges 80 of the tip member and the pile 130 are welded together. Advantageously, a head member 95 which is full of UHPC, and also provided with a flange 80, is attached in the same manner as the head element 94 on the other end of the pile 130.

This makes it possible to respond to any pile configuration by storing only a small number of parts: tip elements 94, elements of tsts 9 "3 t 31su5c -L30 300 ^ 400 # According to a ninth embodiment of the invention described with reference to FIGS. 29 to 31, the method according to the invention is implemented here for producing a curved piece in its longitudinal axis, here a bend 500 at four twenty degrees (Figure 29). Such a room allows the realization of networks, such as non-rectilinear water supply or wastewater collection networks.

This ninth embodiment involves a core 560 which comprises a bent metal tube 561 having a portion 561.1 whose 1 longitudinal axis (X) makes a quarter circle (Figure 30). The inner face of the tube comprises an electric heating cord 562 which makes a spiral. The heating cord 562 is sized to generate surface temperatures of the tube 561 between 30 and 120 degrees centigrade. A wax layer 566 is overmolded onto the tube 561 according to a method identical to that described for the fifth embodiment of the invention, the mold 541 used being of course adapted, that is to say comprising a portion of longitudinal axis in quarter circle. Inner half-sleeves 543a and 543b of the mold 541 are shaped so that one end 561.2 of the core 561 has a stepped annular protrusion 561.3 composed of three annular sections 561.4, 561.5 and 561.6 whose central section 561.5 presents a larger diameter.

Preferably, the wax 566 has a ring and ball softening temperature of between 75 and 115 degrees centigrade. More preferably, the wax 566 has a melting temperature greater than 115 degrees centigrade. The thickness of the wax layer 566 coating core 560 is generally between five and fifty. millimeters.

The manufacture of a bend 500 according to the ninth embodiment will be described with reference to FIGS. 31a to 31g.

A first wire 590 enclosed in a sheath 590.1 curve filled with grease 590.2 is put in place in a CDxrtJL

a quarter circle. A second sheath 590.1 is also positioned in the half-mold 502 (Figure 31a). The ends 591 of the wires 590 are over-extended and extend beyond the sheath 590.1 and the ends of the half-mold 502.

The core 560 is then put into place in the half-mold 502 (FIG. 31b), taking care to make p ** 3. SS and CJ € 5 SS ^ .5 CD CD ZL CD1TlCi »ΓΊ ^" 62 ^" VU, £ 3 cl CD D1. CD ff CB ^" t ΐ 3.ΧΊ S i CD -? CD CD 1 SS c ΓΊ CD CD 5 S1 · 3 ■ The second sheath 590.1 (seen on the section of FIG. 31) is then placed around the core 560, in the same manner as the other sheaths 590.1. A half-mold 503 (not shown) is presented facing the half-mold 502 and secured thereto, thus defining a receiving volume 550 with the core 560 in which in particular the sheaths 590.1 extend. A first end plate 511 comprising orifices 513 for passing the ends 591 of the wires

Î D CD ^ 3 ^"t ^* o -i- JZD ZDCDJC 1- CDC ^ JT jÇDot IZD CD U. -L.CD 3 J c Ί XZT CD" SL U. ΧΊΙCD ^ | 3T CDÏÏXZL CD CD CD ΧΓ end 501.1 mold 501 composed of half-molds 502 and 503 (Figure 31e).

The mold 501 is then arranged so that its second open end 501.2 extends in horizontal plane, and the mold 501 is filled with UHPCF by its second end 501.2. A first BFUP thermocouple 521 and a second wax thermocouple 522 are respectively disposed in the UHPCF and in the wax layer 566 of the core 560 (Fig. 31d). The thermocouple of UHPF 521 and the wax thermocouple 522 make it possible to measure the respective changes in the temperatures of the wax and the UHPC during the molding process. A second end plate 512, identical to the first end plate 511, is bolted to the second end 1.2 of the mold 1 and closes the mold 1 (FIG. 31e).

In this ninth particular embodiment of the method according to the invention, the preload son 590 is not applied before taking the UHPC.

The application steps of the first, second and third temperature setpoints are identical to those of the fifth embodiment of the invention described above and are based on the same temperature measurements. At the end of the third temperature setpoint and the evacuation of the core 560, the elbow 500 is demolded by separating the two half-molds 502 and 503 and the end plates 511 and 512.

The bend 500 thus cast has a first end 510 and a second end 511 projecting from which extend the ends 591 of the son 590. The end 511 comprises a housing 512 of greater diameter than the inside diameter of the bend 500 created by the annular section 561.4 of the 560 core. Sections 1-UL-3 and-5-1-L. · L- _^ ^ _~ ^ L · 5 ^"t. - j ^ ^ _*** * ^* t" - ^* / ^* - ^ ι nΐ _"* ^ 3_r € 5 i" 5 units 513 and 514 in the inside ring elbow 500 (Figure 31. f).

The first ends 591 of the wires 590 are then anchored in known manner in the UHPC of one of the ends of the bend 500, for example by sealing conical bushes in the ends of the sheaths 590.1 present at the first end 510 of the bend 500. another end 591 of the wires 590 is then used to tension each wire 590. This end is then sealed in the wall of the housing 514 (FIG. 31. g).

An annular elastomer seal 515 can then be mounted in the housing 513 and / or 514 to ensure a tight connection of the end of a conduit introduced into the housing 512 with the second end 511 of the bend 500.

The above method can of course also be implemented without the introduction of son 590 and their sheaths 590.1.

Of course, the invention is not limited to the embodiments described but encompasses any variant within the scope of the invention as defined by the claims.

The method according to the invention is thus also applicable to the molding of portions of tubular pieces or

CD-3 TC-Ί Χ-) CD ^ 3 _j CD IT ^"tT \ CD l D _<~ Η-ί CD mj" L, CD CID> S c XTl3- 3 iHLD J-> S CD Ui CID ¾3 portions In this case, the inner element (the core) is rigid - for example metal - and the outer element (the mold) is deformable on command, for example made of wax or polymer. the UHPC being neither hindered on the bow of the core, nor in the flexible mold, the piece undergoes no constraint when it is taken.

In particular,

- Although here the method of the invention is described in connection with the manufacture of a pile, the invention is also applicable to the manufacture of other types of parts, such as tubular pieces of the pipe type or nozzles as well as tubular parts of which at least one end is closed like reservoirs, rechikings, boxes of x ci c co XTci ΘΓΠ, Θnt ow S rciciis ciuss 1 ci CD S multi-tabular wall pieces such as hollow-core slabs or facade panels;

- Although here the method of the invention is described in connection with the manufacture of a pile of 200 mm outside diameter, the invention also applies to the manufacture of piles of different diameter, preferably between 120 and 240 millimeters but also diameters less than 120 millimeters or greater than 240 millimeters;

the pile may have other shapes, internal and / or external, than those described;

- Although here the core is provided with conical centering protuberances, the invention also applies to a core devoid of such protuberances, or provided with other centering means such as pins or rings; the invention also applies to other forms of associated cavities and protuberances such as for example striations, pyramidal indentations or any shape;

- Although here the mold comprises two half-molds provided with notched tabs intended to cooperate with cleats, 1 the invention also applies to a mold that can separate in more than two parts and whose parts are interconnected by other means of solidarization such as for example straps, bolts, bolted flange assembly, or jacks;

- Although here the shell of the core is silicone, the invention is also applicable to other types of polymers such as rubber, PVC or coated fabric; - although here the nucleus is shaped by water filling and solidification thereof, the invention is also applicable to other means of conforming the core such as for example inflation with compressed air;

although here the reception volume is filled by injection of pressurized UHPC, the invention also applies to a gravitational introduction of UHPC in the reception volume;

although here the core 60 comprises three cylindrical wax elements interconnected by wax shafts, the invention also applies to a single-piece wax core or made from the assembly of a different number of waxes. elements;

although here the wax core is heated by injection of hot water or expanded steam into and on the core or by means of a heating cord placed in the core, the invention also applies to other means for heating the core such as, for example, heating in an oven, by induction or microwaves, or by the use of longitudinal prestressing steels as electrical resistances;

Although here the centering wedges are silicone and reported on the core, 1 the invention also applies to other types of centering wedges such as wedges made of other polymeric materials or shims centering under the shape of protuberance provided during the realization of the elements of cores;

although here the centering wedges are of substantially conical shape, the invention also applies to other forms of wedge such as shims of cylindrical, pyramidal or any shape;

although here the establishment of one or two metal flanges has been described in connection with a wax core, the invention also applies to the establishment of one or two metal flanges in the context of the invention. use of any other type of core, such as an elastomer core;

although here the method has been described in the context of the implementation of UHPC, the invention is also applicable to the implementation of other material comprising cement such as standard concrete or mortar;

although here the method has been described in connection with the molding of an externally smooth tube and the interior surface of which is engraved, the invention also applies to other configurations of surface states, such as tubes whose inner face is smooth and the outer face is engraved;

although here the process has been described in the context of the molding of a complete tubular element, the invention is also applicable to the production of half-tubes or fractions of tubes of large diameter. In this case, the mold and the core are semi-cylindrical;

although here the process has been described for an externally smooth and internally formed tube, it also applies to internally smooth and externally formed tubes. In this case, the inner core is rigid and the mold ext

(in wax or polymer). Withdrawing the UHPC is then constrained neither on the arc of the nucleus nor in the flexible mold;

although here the centering of the core is carried out using three prestressing wires, the invention also applies to a different number of prestressing wires, for example two, or more than three;

although here the diameter of the prestressing wires is four millimeters, the invention also applies to prestressing wires of smaller or greater diameter, between one and twenty millimeters;

although here the prestressing wires are anchored to a length of 80 millimeters, the invention also applies to prestressing threads anchored on different, higher or lower lengths. The distance separating the rings as well as the thickness of the coating around the prestressing wires are parameters whose values given as an indication in the description, may be adapted;

although here the process has been described for the molding of a complete tube, it is also applicable to the production of half-tubes or fractions of large diameter tubes. In this case, the mold and the core are semi-cylindrical;

although here the process has been described for an externally smooth and internally formed tube, it is applied to internally shaped and externally formed smooth tubes or to tube portions. In this case, the inner core is rigid and the mold outside is deformable on order. In this configuration, the withdrawal of the UHPC is not constrained either on the arc of the core, or by the deformable mold;

although here the method has been described for a tube, it also applies to the molding of beams having a lower right chord and a bent upper chord connected by a core. In this case, deformable cores arranged on either side of a core (prefabricated or defined by the mold) take the form of a band of peripheral wax;

although here the prestressing means comprise two prestressing mechanisms located at each end of the prestressing wires, the invention also applies to a mold comprising a single prestressing mechanism applied to a first end of the prestressing wires, the another end being locked against the end plate of the mold by an anchor;

- Although here, the means for moving the plate of the prestressing means relative to the end plate comprises two CHC screws, the invention also applies to other moving means such as a single screw or more than two screws, a cam or a jack;

although here the prestressing means are integral with the mold and are supported on it, the invention also applies to mold biasing means separate from the mold and / or which do not bear against it such as a winch, a tire, a jack, but also crutches anchored in the ground associated with transverse trimmers, longitudinal buttresses of concrete or steel associated with transverse headers, the prestressing steels being anchored behind the headers;

- although here the prestressing devices are son ms13111 S 1 in ^* VGn11or also applies to other types of prestressing devices such as metal bars or frames of synthetic materials;

although here the pile comprises four radial connecting channels opening onto a peripheral groove, the invention also applies to a different number of channels, such as for example between one and three or more than four channels. These channels may also extend in non - radial directions as long as the distal end of these channels opens onto the outer peripheral groove of the pile. Thus, the core may comprise a number of excrescences of between one and three or more than four, the growths may also join the ring in any directions;

1 52Ί. C _* 1 JU 1165 J _* 5 ~ L € 5 U. C? C5ΣT J3 Γ € 3Σ ^"1 ^I" l € 2 Ut Ώ. € 5 JCc¾ 1 Ω. As an outer peripheral, the invention also applies to other means for injecting a material from the interior volume of the pile to the outside thereof, such as, for example, elastomeric valves, nozzles, diffusion grids provided with removable elastomeric membrane;

although here the ring mounted at the end of the excrescences of the core is made of elastomer, the invention also applies to other types of rings, such as a polystyrene ring or wax, the channel occlusion device opening into the groove can be mounted after demolding the pile;

although here the prestressing wires are passed in a flange, such a flange is not essential and the invention also applies to piles comprising prestressing wires (or other prestressing devices);

although here the core comprises a heating cord arranged spirally inside a metal tube, the invention is also applicable to other types of core heating means and other types of arrangement such as for example an axial network of hot water pipe, steam or several heating beads positioned inside or outside the tube, the latter may be metallic or in any other suitable material such as fiberglass or wood;

although here the core comprises a straight cylinder tube, the invention also applies to other forms of support such as a square tube, a solid shaft or a tube of any shape;

although here the flange, the ring and the mold half-sleeves are made of polymer, the invention also applies to other suitable types of material such as natural rubber or natural latex;

Although here the ring is glued along a its edges, the invention is also applicable to other securing means of the ring such as anchoring, screwing, or to a ring not secured to the groove;

although here the introduction of UHPC is performed when the mold is positioned vertically, the invention also applies to an introduction of material comprising cement in other mold positions, such as for example a horizontal mold or placed according to any angle to the horizontal;

although here the temperature measurement of the material containing cement and wax of the core is carried out using a thermocouple, the invention also applies to other means of temperature measurement such as for example a measurement by infrared, laser or liquid thermometer, the temperature measuring means may comprise only a single device for measuring the temperature of the only material comprising cement or wax alone, or several devices for measuring the temperature of the material with cement or wax;

the temperatures and times of the heat treatment of the material containing cement are established on the basis of the temperature measurement of the material comprising cement, the invention also applies to temperatures and heat treatment times implemented on the basis of other parameters such as, for example, surface hardness, core temperature, humidity, electrical conductivity ;

- Although here the tensioning of the prestressing threads is carried out after the introduction of the material comprising cement into the mold, the invention also applies to a step of tensioning the pre-stressing threads before the introducing the material comprising cement into the mold. More generally, the order in which the steps are described can be modified;

although here the elbow is a nineteenth degree elbow, the invention applies to any type of tubular part whose longitudinal axis comprises a portion of a curve, such as for example a fifteen, thirty elbow. five, forty-five, sixty, or any angle.

For the purposes of the present description, a mortar is a mixture comprising a hydraulic binder composed of cement or a mixture of cement and ground vitrified blast furnace slag, a detrital rock load with a particle size of between 64 micrometers ( pm) and 2 millimeters (mm) in a standard commercial tolerance and optional adjuvants such as substances intended to modify the consistency of the mortar, its setting time, its tightness or its resistance to freezing. Finally, the mortar may also comprise synthetic fibers or metal fibers. Reference is made to standard NF EN 206-1 for the definition of concretes.

Claims

A method of molding a workpiece (100, 110) made of a material comprising cement comprising the steps of:

placing at least one prestressing device in a first element;

placing the first element (20, 60) opposite a second element (1) so that the outer wall (21.1, 60.1) of one of the elements (20, 60) delimits with the inner wall ( 6.1) of the other element (1) a receiving volume (50), the shape of one of the elements (20, 60) being modifiable to order; introducing the material comprising cement (51) so as to fill the receiving volume (50);

prestressing the at least one prestressing device by applying a tensioning force thereto;

- control a progressive change in the shape of one of the elements (20, 60) as and when taking the material comprising cement (51);

demolding the workpiece (20, 60).

The molding method according to claim 1, wherein the piece is tubular (100, 110), the method comprising the following steps:

placing at least one prestressing device in a cylindrical mold (1);

- placing a core (20, 60) in the cylindrical mold (1) so that the outer wall (21.1, 60.1) of the core (20, 60) delimits with the inner wall (6.1) of the mold (1) a tubular receiving volume (50), the shape of the core (20, 60) being modifiable to order; introducing the material comprising cement (51) so as to fill the tubular receiving volume (50); prestressing the at least one prestressing device by applying a tensioning force thereto;

- control a progressive change in the shape of the core (20, 60) as the cement-containing material (51) is taken until a core shape (20, 60) is obtained for its extraction from the workpiece tubular (100, 110) after at least partial setting of the material comprising cement (51);

- removal of the core (20, 60);

demolding of the tubular piece (20, 60).

3. The molding method according to one of the preceding claims, comprising a step of applying a heat treatment to the material comprising cement.

4. The molding method according to one of the preceding claims, wherein the temperature of the material comprising cement is measured.

5. The molding method according to claims 3 and 4, wherein the temperatures and the durations of the different phases of the heat treatment step are established as a function of the measured temperature of the material comprising cement.

The method of claim 2, wherein the core (20, 60, 360, 560) is at least partially made of wax (66, 366, 566).

The method of claim 6, wherein the ball and ring softening point of the wax (66, 366, 566) is between 75 and 115 degrees Centigrade.

The method according to any one of claims 2 to 7, wherein the core (360) comprises at least one outgrowth (489.1, 489.2, 489.3, 489.4) whose distal portion joins a ring (488), so as to create a link channel (486) between a volume interior (406) of the tubular piece (400) and an outer peripheral groove (487) of the tubular piece.

9. The method of claim 8, wherein the ring (488) is of polymer.

A tubular pile (100, 110, 120, 130, 300, 400, 500) of ultra-high performance fiber-reinforced concrete molded according to the method of any one of the preceding claims.

11. Core (20, 60, 360, 560) customizable form for the implementation of the method according to any one of the preceding claims.

The core (20, 60, 360, 560) of claim 11, comprising a metal tube (361, 561) coated with a wax layer (366, 566).

13. Core according to claim 11, wherein the wax (366, 566) has a melting point greater than 115 degrees Centigrade.

14. Core (20, 60, 360, 560) according to claim 11, comprising heating means.

15. Core according to claim 14, wherein the heating means comprise at least one heating cord.