FR2719518A1 - Precast concrete element as well as device and method for its manufacture. - Google Patents

Abstract

The invention relates to a process for the production of precast concrete elements serving as lost formwork, process in which the concrete not yet solidified is introduced into a negative mold (1) under a pressure of up to 4 bars. The invention also relates to a device for implementing the aforementioned method, the negative mold used in this method being composed of several elements (10, 11 and 12) sealed relative to each other by means of gaskets. rubber seal (4). Finally, the invention relates to a precast concrete element obtained by casting as a one or two-piece basement window jamb.

Description

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  Precast concrete element and device and method for its manufacture

  The present invention relates to a method for manufacturing

  cation of precast concrete elements used as formwork

  lost, in which the not yet solidified concrete is introduced

duit in a negative mold.

  It is known to produce precast concrete elements.

  industrially in the factory and to supply the elements in

  precast concrete finished on site where they are then laid.

  In this case the precast concrete elements are also used as lost formwork. For the production of

  precast concrete elements are used molds nega-

  tifs into which the liquid concrete is poured.

  Concrete properties depend to a large extent

  of its composition. Concrete is predominantly made up of

  cement, water, aggregates and other additives. Depending on the proportion of these different materials can therefore be adjusted the physical properties, such as for example

  the density or compressive strength of the

  your. Traditional concrete, for example, has a resistance

  this at compression of 45 newtons per square millimeter. This concrete is called concrete B45. Now if we want to get a

  precast concrete element with adequate mechanical strength

  corresponding, then it is calculated, for the use concerned

  born from concrete of quality class B45, minimum mechanical resistance of the precast concrete element. The precast concrete elements are made by dimensioning the negative molds accordingly. Thanks to the development of concrete with high mechanical resistance (HSC = High Strength Concrete) it is now possible to manufacture concretes in the mechanical resistance class between B60 and B135 and more. Thus it becomes difficult to reduce the cross-sectional areas in the precast concrete elements of such

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  so that the load capacity of the concrete element pre-

  manufactured remains unchanged. Negative molds have small sections. The problem, however, is that

  that the concrete no longer flows into the negative mold presented

  both these relatively small sections. The object of the invention is to propose a method of the kind described above which makes it possible to manufacture precast concrete elements whose cross-sectional areas are at this point.

small.

  To achieve this object, the present invention starts from a process of the kind described above and proposes that the concrete be introduced under pressure into the negative mold. The concrete is pushed into the negative mold by the pressure exerted, so that now the concrete also flows through

  the small sections now become possible.

  In a preferred embodiment of the invention it is proposed to introduce the concrete by pumping at the lowest point of the negative mold. The negative mold is arranged for example in an inclined manner or on edge. If the concrete is now introduced at the lowest point by pumping it is

  at the same time provided that the air in the mold can-

  escape to the highest point of the negative mold. This prevents air bubbles from forming in the element

in precast concrete.

  It is advantageous to add glass fibers to the concrete.

  re. Glass fibers, for example glass fibers ha-

  are incorporated into the concrete to increase elasticity

  concrete. By means of glass fibers is at the same time

  Slightly reduced the brittleness of concrete. Due to the incorporation

  tion of glass fibers the fluidity of concrete decreases. The utility

  The process according to the invention makes it possible to manufacture a precast concrete element with small sections and this

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  even if the concrete contains certain proportions of glass fibers. It is advantageous to add a plasticizer to the concrete. The fluidizer increases the ability to slide since the fluidi-

  fiant reduces the surface tension of water in concrete.

  Very good results have been obtained when

  silicon plies were incorporated into the concrete. Thanks to the ap-

  wearing silicon or silicates, in particular silica-

  Since your sintered minimum dimensions come from smoke gas recombination plants, it is made of concrete with high mechanical resistance. When the concrete sets, the heat of hydration released is used to crumble the silicon crystals. These silicon crystals now perfectly fill the hollow spaces formed

  in concrete and make it even more compact.

  For example, a dose of silicon is added to the concrete

  or silicates from 15 to 30% by weight. Silicon not alone-

  ment increases the mechanical resistance of concrete but also acts

  as a filler in concrete. In addition, the use of silicon is more advantageous than the use of concrete. he

  This results in more advantageous manufacturing costs for the

precast concrete element.

  It has proven to be advantageous for the concrete to be introduced

  in the mold under a pressure of up to 4 bars.

  In addition, the invention proposes that the concrete introduced is preferably shaken when it is introduced into the

  mold. It is known that shaking serves to consolidate

  your. In combination with the introduction of concrete, especially tough concrete, in negative molds with a small cross-section shaking not only makes it possible to consolidate the concrete but also to make the concrete more apt to slip because it

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  is shaken directly into

  the hollow spaces still free from the negative mold. This pro-

  position according to the invention allows the process to be shortened

  brication of the precast concrete element because the concrete can thus be introduced more quickly into the negative mold.

  At the same time the density of the concrete is increased.

  It is advantageous that the device for implementing

  vre of the process comprises a negative mold which consists of

  several elements and that mold elements are sealed

  bound to each other by means of gasket

  rubber sealing. It is also advantageous to use

  use rubber seals for sealing.

  It is at the same time possible to assemble different elements

  mold, like a construction toy, for a mold

  the desired negative, in which case many variants of

  precast concrete elements are possible, but do not require

  where only a small number of mold elements. In addition, the rubber compensates for slight dimensional inaccuracies

  individual mold elements relative to each other

  very. Thanks to the use of rubber seals

  chouc between the different components of the mold there

  it is also possible to quickly manufacture molds

  gifs of different types with a reduced stock of elements of

corresponding mold.

  According to the invention it is possible to produce an element

  in precast concrete with small cross-sectional areas.

  The method described above makes it possible to manufacture a precast concrete element whose load capacity is, thanks to the high quality concrete used, the same as that of precast concrete elements having significantly larger sections. Thanks to such a precast concrete element according to the invention, concrete is saved. This results, on the one hand, in a price advantage and, on the other hand, a weight

  reduced by the precast concrete element.

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  It is advantageous that the precast concrete element is obtained by casting as a single-piece basement jamb. Portholes are subjected, as

  that part of the formwork of cellars of a building, strong con-

  treacherous. This proposal according to the invention makes it possible to

  briquing of high-capacity valve lids

  load city, while their manufacturing cost is lower

  laughing at that of the legs of known air vents.

  Advantageously, the basement jamb consists of two parts forming a frame cast in one piece. A

  chassis part constitutes in this respect the external chassis

  while the other constitutes the inner chassis of the

  air vent jamb. Thanks to the division of the supporting leg

  pirail in two parts one can easily form various types of jambs of air vents with interior frames

and different exteriors.

  The invention is shown diagrammatically in the appended drawings in which: FIG. 1 represents a vertical section through a precast concrete element according to the invention; Figure 2 shows a vertical section through a

  device according to the invention for implementing the process

of;

  FIG. 3 represents an embodiment of the device.

  positive modified from Figure 2; FIG. 4 represents a vertical section of a detail of a precast concrete element according to the invention; and

  FIG. 5 is a top view of FIG. 4.

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  In Figure 1 is shown a concrete element pre-

  manufactured according to the invention. In this case the element in be-

  your prefab is made in the form of an air vent jamb 5. This consists of two parts, the inner frame 51 and the outer frame 50 being connected together by a connecting member 52. The slot 53 between the two chassis 50, 51 provides sound and thermal insulation

  because the inner region is decoupled from the outer region

  re. In the slot 53 is provided insulating material 2 for

  increase the thermal insulation of the air vent jamb 5.

  Both the outer chassis and the inner chassis pre-

  feel rebates 54 (on the outer frame 50) and

  rebates 55 (on the inner frame 51). It is at ni-

  calf of these rebates 54, 55 that the basement window is slid in place and fixed. The window jamb 5 has for example

  on three sides an outer rebate 54 at the level of the

  which window, in this case not shown, is slid

  seated in place and supported. The window is then dragged in

  place behind the interior rebate.

  There are several advantages to making the vented jamb 5 in two parts. On the one hand, it is possible to combine different exterior frames 50 with different interior frames 51. By means of a small number of shapes

  basic so we get a lot of soup legs

  finished rail 5. In addition, the inner frame 51 has

  example of interior surfaces 56 extending in an

  clined from outside to inside. These interior surfaces

  They can only be made with difficulty in the case where the air vent jamb 5 is made in one piece (that is to say with the outer frame 50). It is in this respect more advantageous to manufacture the outer frame 50 and

  the inner frame 51 as prefabricated concrete elements

  separate bricks. The manufacture of chassis elements

  different 50 and 51 is shown in Figures 2 and 3.

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  In Figure 2 is shown a device according to the

  vention to produce the precast concrete elements. In this case the negative mold 1 is formed from several mold elements 10, 11 and 12. The mold elements 10, 11 and 12 are sealed with respect to each other by seals

  4. As a constituent material of watertight seals

  rubber 4 is used for example rubber. The rubber is distinguished in this respect by its elasticity thanks to which certain dimensional deviations of the mold elements 10, 11 and

  12 relative to each other are offset by a screen

  seals 4.

  In addition, the rubber seal is not attacked by the concrete 3 introduced under pressure into the mold.

negative 1.

  In Figure 2 is shown the vertical section at

  through a negative mold 1 forming the outer frame 50.

  To make the negative mold 1 are used here.

  Several mold elements are used. It is for example possible

  ble that the mold element 12 extends in one piece to the

  around the entire edge of the negative mold. During the fa-

  brication it is for example applied with insulating material 2 on the upper and lower edges of the mold element 11 forming a frame. This insulating material can for example be applied by gluing. The insulating material introduced

  2 therefore forms, in the precast concrete element, spacers

  these filled hollows 20. As a result of appropriate intervals between

  between regions with insulating material 2 we obtain between the

  hollow paces 20 of the supports 21 in the form of ribs. this is

  shown as an example in Figure 3.

  The different mold elements 10, 11 and 12 are used

  res against each other for example by means of clamps

  tightening joint with screws and therefore form the negative mold 1.

  The mold element 11 has in this case a shape in

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  U, the branches of the U pressing against the water seal

  sheaity 4. The mold element 10 is produced asymmetrically

  S-shaped. The mold element 12 is U-shaped and pre-

  feels a recess 71. Between the mold elements 12 and 10 is provided a spacer block 70. The spacer block 70 is located on the recess 71. On the mold element 10 is provided a fixing sheet 67 which cooperates with a joint

  seal 4 mounted on the mold element 12.

  In Figure 3 is shown schematically the fa-

  brication of the inner chassis 51. This chassis has an E-shaped section, the long core of the E being inclined

  since the three branches forming the E have long

  decreasing feats. The branches are in this case

  rence designated respectively by 60, 61 and 62 while the core is designated by 63. Between the branches 60 and 61 is a hollow space 20 which is filled with insulating material

  2, as well as the hollow space 20 between the branches 61 and 62.

  The negative mold 1 used to form an internal frame 51 according to FIG. 3 is in this case made up of four mold elements 13, 14, 15 and 16. The mold elements 13, 14, 15 and 16 are also sealed. relative to each other by means of seals 4. For simple mounting of the negative mold 1 the mold element 15 has, in the region of the core 63, a support plate 65 fixed by means of a weld bead 64 and on which the core is supported and on which the mold element 16 which bears

essentially forms the soul 63.

  The mold element 13 is for example in the form of a U, the branches of the U being oriented towards the outside. The mold element 15 is made in an S shape, while the elements

  mold 16 and 14 are elongated. For better handling

  lity the mold element 14 has at its ends cor-

  L 66 niers. The 66 angles are also supported

against the seal 4.

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  To manufacture according to the invention the concrete element pre-

  fabricated the negative mold 1 formed from the mold elements is for example placed on edge. Liquid concrete, viscous and for example of high mechanical strength is now at an opening, arranged for example in the lower region of the negative mold formed of mold elements (and which is not shown in the occurrence), introduced under pressure into the negative mold by pumping. The negative mold 1 has on its upper side an air exhaust port, not shown. The air displaced by the introduced concrete

  by pumping escapes through this air exhaust port.

  In Figure 4 is shown in detail the li-

  aison 52 by means of which the two chassis 50 and 51 are connected

  between them. The connecting member 52 is here for example

  folded into a U, the free ends of the U carrying a thread

  and projecting, for example, into the inner frame 51.

  The two frames 50 and 51 have openings through

  which the connecting member 52 is guided. The organ of li-

  aison 52 is secured for example by means of nuts 58. On the outer chassis side of the connecting member 52 is

  a slot in which a socket 56 can be hung.

  The sleeve 56 carries for example a thread and is used to connect

  said precast concrete element to other concrete elements

  your prefabricated. It is for example provided, when for example-

  ple the prefabricated concrete element proposed is made in the form of a valve jamb, to connect the

  sliding from the air vent to the socket 56.

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Claims (10)

  1. Process for the production of concrete elements   manufactured as lost formwork, in which the concrete not yet solidified is introduced into a negative mold, characterized in that the concrete is introduced under pressure into the negative mold.   2. Method according to claim 1, characterized in that the concrete is introduced by pumping at the most bottom of the negative mold.   3. Method according to claim 1 or 2, characterized in   that glass fibers are incorporated into the concrete.   4. Method according to any one of the claims   above, characterized in that fluidizer is incorporated brought to concrete.   5. Method according to any one of the claims   previous, characterized in that silicon compounds are incorporated into the concrete.   6. Method according to any one of the claims   previous, characterized in that concrete is introduced   in the mold under a pressure of up to 4 bars.   7. Method according to any one of the claims   previous, characterized in that the negative mold is   preferably shaken when concrete is introduced.   8. Device for implementing a method according to   any one of the preceding claims, characterized   in that the negative mold (1) consists of several   mold elements (10 to 16) and in that the mold elements   1! the (10 to 16) are sealed against each other   by means of rubber seals (4).   9. Prefabricated mold element which serves as lost formwork and is manufactured by the process according to any one   of claims 1 to 7, characterized in that the element in   precast concrete is obtained by casting as a jamb   air vent (5) in one piece.   10. Precast concrete element according to claim   9, characterized in that the basement window jamb (5) is   made up of two chassis elements (50, 51) obtained in dividually by casting.