WO1986000881A1

WO1986000881A1 - Aggregate cement construction element and method and device for making the same

Info

Publication number: WO1986000881A1
Application number: PCT/CH1985/000119
Authority: WO
Inventors: Ludovic Hunkeler
Original assignee: Ludovic Hunkeler
Priority date: 1984-07-27
Filing date: 1985-07-29
Publication date: 1986-02-13
Also published as: ES8607800A1; AU4609985A; ES538794A0; EP0188557A1

Abstract

The method relates to the making of a construction element having good thermal and sound isolation characteristics from low cost products and by using simple techniques. The method comprises particularly the following operations: cutting or tearing paper, humidifying said paper and mixing it with wet cement in order to obtain a homogenous paste, casting said paste in a mould and compacting the paste while evacuating excess water. Preferably the compaction is carried out by means of a press. A mould (42) comprises a bottom having perforations (44) for enabling water to flow, and a movable cover (45) which may slide in the mould. In particular, the invention enables to obtain solid or recessed isolating plates or panels, useable in the building industry or in civil engineering.

Description

Construction element agglomerated with cement as well as process and device for its manufacture.

The present invention relates to a method of manufacturing a cement-based building element. It also relates to an installation for manufacturing construction elements agglomerated with cement, for the implementation of this process, equipped with at least one mixer for preparing a homogeneous paste. The invention also relates to a building element resulting from said method, as well as the use of such a building element.

Numerous processes are already known for manufacturing construction elements agglomerated with cement, making it possible to obtain rigid elements, but relatively porous, in order to present good qualities of thermal insulation. A first category of processes consists in making a cellular concrete, containing a multitude of bubbles, thanks to the addition of foaming products or materials giving off gases in the presence of cement, for example an aluminum powder. However, these methods are relatively expensive since they require complex operations requiring high precision, special installations such as autoclaves or expensive special products. In addition, the elements obtained can give rise to undesirable chemical reactions when they are in contact with fresh mortar or concrete.

Another category of process uses light aggregates, for example pumice stone, clay expanded by baking, mineralized wood, etc. The elements obtained by these processes are also relatively expensive because of the price of light aggregates.

Therefore, the present invention aims to provide a method and an installation for manufacturing elements of construction agglomerated with cement, using basic products which are abundant and inexpensive, simple techniques easily mastered by construction professionals, and machines common in prefabrication workshops, in order to obtain an inexpensive element, with good thermal insulation characteristics and usable without difficulty with traditional building materials.

For this purpose, the manufacturing method according to the present invention is characterized in that the following successive operations are carried out: cutting or tearing paper, moistening the paper, kneading together a determined quantity of the cut or torn paper, to make it a homogeneous paste, pour a determined quantity of this paste into at least one mold provided with openings allowing the flow of water, compact this paste in the mold, unmold the product thus obtained and ensure its hardening and drying.

The installation for manufacturing construction elements agglomerated with cement, for the implementation of this process, is characterized in that it comprises, upstream of the mixer, a machine for cutting sheets of paper, a device for humidification of the paper and a cement mixing device, and in that it comprises downstream of the mixer at least one perforated mold provided with a movable cover and a press arranged to produce a displacement of the cover so as to compress the dough placed in the mold.

A building element resulting from the method according to the present invention is characterized in that it essentially comprises paper bound by cim-ent.

A characteristic use of a building element according to the present invention, produced in the form of a flat plate, has for object the thermal insulation of a roof. However, such a construction element has many other possibilities of use, which are discussed below.

The present invention, its particular characteristics and its advantages will be better understood with reference to the description of an embodiment, given below by way of example, and to the accompanying drawings, in which:

FIG. 1 is an overall diagram of an installation for manufacturing construction elements according to the present invention,

FIG. 2 is a perspective view, partially cut away, of a mold for a flat plate,

FIG. 3 is a schematic sectional view of a mold for a ribbed plate,

FIG. 4 is a sectional view of a composite element produced according to the present invention,

FIG. 5 is a schematic sectional view illustrating a use of a building element according to the invention, and,

Figure 6 is a schematic sectional view illustrating another use of an element according to the invention.

With reference to FIG. 1, a plant for manufacturing construction elements according to the present invention essentially comprises, for the preparation of paper, a balance 10 used for weighing determined quantities of paper to be used for manufacturing, a machine 11 for cutting paper, of a type known per se, and a device 12 for moistening the paper. Machine 11 cuts or tears sheets of paper, which she reduces into thin strips a few millimeters wide and of variable length. The humidification device 12 can comprise either a soaking tank, in which the cut paper is soaked with water supplied by a supply device 13, or a grid conveyor, on which the cut paper is subjected to watering, then to a drain. In a particular embodiment of the invention, in which reinforcing fibers are mixed with paper, the manufacturing installation comprises, between the cutting machine 11 and the humidification device 12, a premixer 14 in which the strips of paper are dry brewed with reinforcing fibers, until a sufficiently homogeneous mixture is obtained.

On the other hand, for the preparation of a cement grout, the installation comprises a grout mixer 20 which receives water from the feed device 13 via a metering member 21, cement of a silo 22 via a metering member 23, and an optional adjuvant of a reservoir 24 via a metering member 25. This type of installation for preparing a grout of cement is well known in the construction industry, especially for injection work.

A primary mixer 30 is arranged to perform a rough mixing of the cement slurry with the cut and moistened paper. To this end, it is equipped with a paper hopper 31, provided with a metering member 32, and with a metering pump 33 for the cement slurry. A pipe 34 fitted with a manual valve 35 makes it possible to add water to the primary mixer if necessary. The installation also comprises a series of secondary mixers 36, which are intended to carry out prolonged mixing of the mixture and which are each equipped with a distribution hopper 37. A transfer member 38, constituted for example by a monorail equipped with '' a grab 39, is disposed between the primary mixer and the secondary mixers for transporting the mixture.

The secondary mixers 36 are distributed along a prefabrication line 40 of the agglomerated elements. This line is served by a roller conveyor 41 on which molds 42 can be made to circulate. By the conveyor 41, the molds reach a press 43 whose upper plate 34 is movable. A cover 45, corresponding to the mold 42, is fixed under the upper plate 44 of the press, so that it can slide vertically in the mold placed on the press when the latter is actuated. The molds and their covers will be described in more detail below.

The prefabrication line further comprises an oven 46, connected to a steam production installation not shown, a demolding area 47 and a dryer 48 for the manufactured elements.

The manufacturing method according to the invention is clear from the description of the operation of the manufacturing installation illustrated in FIG. 1. A weighing quantity of paper is weighed on the balance 10, preferably corresponding to the capacity of the primary mixer 30, then this paper is cut into strips by means of the cutting machine 11. If it is desired to manufacture an element reinforced with fibers, for example cellulose fibers, textile waste, glass fibers, etc., it is mixed these fibers to the paper cut in the premixer 14 before the moistening of the paper. Otherwise, the paper strips leaving the cutting machine 11 are sent directly to the humidification device 12, in which the paper is soaked with water, then to the paper hopper 31 of the primary mixer 40. It note that the humidification device 12 also makes it possible, if necessary ", to treat the paper with any product suitable chemical, for example to promote its adhesion to cement paste.

The preparation of a cement slurry in the grout mixer 20 is well known to those skilled in the art. It will be noted that it is advantageous to use a setting accelerator adjuvant, as well as one of the traditional adjuvants to stabilize the grout, which must be very fluid.

After having been introduced into the primary mixer 30 by their respective metering members 32 and 33, the cut paper and the cement slurry undergo a first, relatively brief mixing, then this mixture is poured into the bucket 39 to be transferred into the one of the secondary mixers 36, in which the mixing of the mixture is completed. In fact, it turns out that obtaining a homogeneous paste from such a mixture requires a relatively large kneading time, for example of the order of ten minutes. To ensure a sufficient production rate using standard size mixers, it is therefore necessary to use several mixers. In the arrangement described above, only the primary mixer 30 is equipped with components supply and metering members, which simplifies the equipment, its command and the control of manufacture. In addition, a new batch can be prepared in the primary mixer 30 while the previous batches undergo prolonged mixing in the secondary mixers 36. On the other hand, the secondary mixers can serve as buffer organs, keeping a batch for a some time if difficulties delay production on the prefabrication line 40.

It should be noted that, according to a particular form of the process, it is possible to add to the mixture of paper and cement slurry, in the primary mixer, inert granular materials, for example sand, sawdust or wood chips, textile or other fibers, pigments, liquid or powder chemicals, etc., to modify the qualities of the finished product.

After obtaining a homogeneous paste in a secondary mixer 36, this paste is distributed in molds 42 by means of the distribution hopper 37 of the mixer. The molds 42 are then brought successively to the press 43, in order to compact the dough by compressing it in the mold by means of the corresponding cover 45 fixed to the press. According to a preferred embodiment of the method, to manufacture relatively rigid and resistant elements, the pressure exerted by the press 43 is maintained for a certain time, so as to expel the excess water from the dough and to substantially increase the compactness of the fabricated item. The water is discharged through openings provided for this purpose in the mold, which will be described in more detail below.

During manufacturing tests, it has been observed that it is advantageous to reduce the thickness of the dough contained in the mold substantially by half during press compaction, in order to produce relatively resistant elements, for example studs. insulation or self-supporting insulation plates. Elements are thus obtained whose apparent density is of the order of 0.5 kg per dm ³ . If, on the contrary, it is desired to produce particularly light elements, only a slight press compaction is carried out, or else vibration compacting, the excess water being removed later during drying.

Note that the device described above allows the use of covers of different shapes without changing the shape of the mold. For example, one can manufacture by means of the same molds plates whose two faces are planar and plates whose upper face has reinforcing ribs. Once formed by means of the press 43, the manufactured elements are treated in a traditional manner in the oven 46 in order to accelerate the setting and hardening of the cement, then they are removed from the mold and placed in the dryer 48, where they are subjected natural or forced ventilation, to evacuate the rest of the excess water.

FIG. 2 illustrates a mold 42 used in the installation shown in FIG. 1, with the corresponding cover 45, for manufacturing flat insulating plates, one face of which is smooth and the opposite face is rough. This mold comprises a rectangular frame comprising four vertical side walls 51 provided with stiffeners 52. The bottom of the mold comprises a rigid plate 53, which is provided with a large number of perforations 54 allowing the evacuation of water during compaction. The plate 53 rests on crosspieces 55 which keep it raised relative to the lower plate of the press, to provide between them channels 56 for discharging the water. The perforated plate 53 is covered with a fine grid 57, which produces a rough but regular surface of the insulation plate to be manufactured.

The cover 45 of the mold 42 is arranged to slide freely in the vertical direction inside the frame 51. In the example shown here, where it is intended to produce a smooth face on the insulation plate to be manufactured, it comprises simply a rigid plate 58 which is stiffened by a frame 59 and crosspieces 60.

On the prefabrication line, the mold 42 is filled more or less high depending on the thickness of the plate to be manufactured, then it is brought into the press 43, the bottom of the mold resting on the lower plate of the press. When the upper plate of the press is lowered, the cover 45 enters the mold and compresses the dough which it contains. Under the effect of this pressure, the excess water of this dough filters through the mass and gradually escapes from the mold through the perforations 54 of the fon-d. It is obviously possible to make molds having perforations through the cover, or even through the side walls. Molds of this type can be useful for making insulating pads. However, in the manufacture of the plates, it is preferable to use a non-perforated cover, in order to obtain at least one smooth face.

The lid of the molds may have projecting elements on its underside, for shaping or cutting the dough contained in the mold.

FIG. 3 shows in section an example of a cover 45a, the rigid plate 58 of which is lined, on its lower face, with several forming plates 61, to make recesses in the upper face of a ribbed plate 62 to be manufactured, shown schematically in broken lines. Similarly, one can equip the underside of the cover with vertical knives used to divide the dough contained in the mold into several products.

FIG. 4 shows a hollowed-out insulating panel 63 produced according to the present invention, by assembling a ribbed insulating plate 62 with a flat insulating plate 64.

The tops of the ribs 65 of the ribbed plate are simply glued against the flat plate 64 by means of an appropriate adhesive, for example a mortar, synthetic adhesive, epoxy resin, etc. Such a hollow panel provides excellent thermal insulation at a minimal weight.

The building elements produced according to the present invention have various remarkable characteristics; above all, they provide very good thermal and sound insulation. For example, for plain bricks Only from cut paper, cement and water and having after drying an apparent density of about 700 kg per m ³ , coefficients of thermal conductivity of the order of 0.14 W / mK were measured. Through a bare wall made with 65 mm insulating studs and weighing 45 kg per m ² , a weighted attenuation of the sound level R ' _w = 35 dB was measured according to standard 150 717/1.

Thanks to these characteristics, as well as to the very good stability of the material, it is possible advantageously to use in buildings construction elements according to the invention, particularly in the form of insulating elements such as: vertical or horizontal insulation plates walls or roofs fixed by gluing or nailing, single or double vertical insulating panels, self-supporting or fixed on a wooden frame or other, non-load-bearing walls or brick walls made of insulating stud masonry, hard plates for soil insulation and flat roofs, etc. Because it is possible to produce plates having a smooth face, panels according to the invention can be coated directly with a paint or wallpaper. They also offer excellent adhesion to a plaster coating.

It is also possible to produce a prefabricated plastered panel, by means of a plate according to the invention, about 2 to 3 cm thick, provided on each face with a plaster coating of a thickness of about 1.5 cm. . A panel is thus obtained having excellent sound and thermal insulation which advantageously replaces the solid plaster panels currently used.

Elements according to the present invention can also be used advantageously in combination with concrete, in particular reinforced concrete. FIG. 5 illustrates the use of insulating plates 70 applied against the underside of a slab 71 of reinforced concrete, to obtain insulation thermal and phonic on the ceiling of an industrial premises. During the production of the slab 71, the insulating plates 70 are simply placed at the bottom of the formwork of the slab, in the manner of a lost formwork, before reinforcement and concreting of the slab. Thanks to the roughness of the surface of the plates 70 and their cement-based constitution, they bind perfectly to the concrete of the slab.

FIG. 6 illustrates the use of light elements 72 according to the invention as lost formwork for producing a reinforced concrete slab 73 having ribs 74. The realization of the slab is similar to that of the example in the figure 5. This application is particularly advantageous for producing a cross-ribbed slab.

It should also be noted that insulating plates or pads produced according to the present invention can be used outside a building, for example on the facade, by being coated with a waterproof synthetic plaster.

It is also possible to envisage using these elements in place of the traditional elements of thermal or sound insulation, for insulating machine covers, vehicles from tanks, etc. Thanks to their good resistance to mechanical and / or thermal stresses, it is possible to envisage a longer service life than that of traditional synthetic elements.

Claims

1. A method of manufacturing a construction element agglomerated with cement, characterized in that the following successive operations are carried out: cutting or tearing paper, moistening the paper, kneading together a determined quantity of cement and water with a determined quantity of the cut or torn paper, to make it a homogeneous paste, pour a determined quantity of this pulp into at least one mold provided with openings allowing the flow of water, compact this pulp in the mold, unmold the product thus obtained and ensuring its hardening and drying.

2. Method according to claim 1, characterized in that a cement and water slurry is prepared, which is then kneaded with the cut or torn paper.

3. Method according to claim 1, characterized in that the reinforcing fibers are mixed with paper.

4. Method according to claim 1, characterized in that inert granular materials are mixed with paper, cement and water.

5. Method according to claim 1, characterized in that the paper is mixed with cement and water in a primary mixer, equipped with metering components, then this mixture is transferred to a secondary mixer , in which prolonged mixing is carried out while preparing a new mixture in a primary mixer.

6. Method according to claim 1, characterized in that water is extracted from the dough by compressing it in the mold by means of a press.

7. Method according to claim 1, characterized in that a first and a second element are manufactured, and in that these two elements are assembled by gluing to produce a composite element.

8. Installation for manufacturing construction elements agglomerated with cement, for implementing the method according to claim 1, equipped with at least one mixer for preparing a homogeneous paste, characterized in that it comprises upstream from the mixer a machine for cutting sheets of paper (11), a device for moistening the paper (12) and a device for mixing the cement (20), and in that it comprises at least downstream of the mixer a perforated mold (42) provided with a movable cover (45), and a press (43) arranged to produce a displacement of the cover so as to compress said dough placed in the mold.

9. Installation according to claim 8, characterized in that it comprises a weighing device (10) of the dry paper.

10. Installation according to claim 8, characterized in that it comprises a series of molds (42) open upwards, this opening being of the same dimensions for all the molds in the series, and a cover (45) whose dimensions correspond to this opening, this cover being arranged to slide inside the molds to exert compression on the contents of the mold, and in that the molds have openings (54,56) for the evacuation of water.

11. Installation according to claim 10, characterized in that a mold (42) has a bottom provided with a grid (57) for the flow of water leaving the mold.

12. Installation according to claim 10 or 11, character mock in that the lid (45a) of the molds has projecting elements (61) on its underside, for shaping or cutting the dough contained in the mold.

13. Installation according to claim 8, characterized in that it comprises a primary mixer (30), equipped with metering members (32,33) of the components of the mixture to be mixed, a series of secondary mixers (36) equipped with distribution members (37) in the molds, and transfer members (38,39) of the mixture from the primary mixer to the secondary mixers.

14. Building element resulting from the method according to any one of claims 1 to 7, characterized in that it essentially comprises paper bonded by cement.

15. Building element according to claim 14, characterized in that it comprises a substantially planar plate, one of the faces of which is smooth and the opposite face is rough.

16. Construction element according to claim 14, characterized in that it comprises at least one plate (62), one face of which is provided with ribs (65).

17. Construction element according to claim 16, characterized in that it comprises two plates (64, 65) assembled by gluing so as to constitute a hollow element.

18. Use of a building element according to claim 14, produced in the form of a flat plate, for the thermal insulation of a roof.