FR2964991A1 - IMPROVING A PROCESS FOR PRODUCING AT LEAST ONE VERTICAL LAND BASED ON EARTH - Google Patents

Abstract

The invention proposes a method of manufacturing at least one vertical earth-based wall, comprising at least a first step of preparing a substantially vertical formwork element (12, 18) that determines the thickness of the wall. performing a second step of preparing an earth material (22) during which a mixture is prepared comprising at least silt soil, quicklime, and cement, to obtain said material, and successively to least a third step of filling a cavity (20) of the shuttering element (12, 18) with the material, at least a fourth step of placing the material, a fifth step of drying the material and a sixth step of disassembling the formwork (10), the prepared mixture comprising at least 70 to 98% clay loam soil and / or sandy, 1 to 10% quicklime, and 1 to 15% cement.

Description

FIELD OF THE INVENTION The invention relates to an improvement to a method of manufacturing at least one vertical wall made of earth.

The invention relates more particularly to a method of manufacturing at least one vertical wall based on earth, comprising at least a first step of preparing a substantially vertical formwork element determining the thickness of the wall to be made, a second step for preparing a soil material in which a mixture is prepared comprising at least silt soil, quicklime, and cement, and successively at least a third step of filling a cavity of the formwork element with the material, at least a fourth stage of placing the material, a fifth step of drying the material and a sixth step of disassembly of the formwork. The construction of vertical earth-based walls has been known for a long time. One of these types of construction, commonly known as "rammed earth" is the use of compacted raw earth in a formwork or bunch. The earth is thrown into the formwork in small layers of 0.10 m to 1 m, then compacted manually in the formwork with a pestle. This type of construction makes it possible to obtain a ground-based wall that is sufficiently porous to allow ideal breathing of the premises it delimits, but its use is limited to reduced heights because of the low compressive strength of the building. material used. It is therefore not possible with this method to raise high walls. Furthermore, the "rammed earth" is by its porosity very sensitive to erosion and therefore offers only a limited duration of time. To overcome this drawback, it has been proposed in FR-2935.008 a new construction method 2 using a new material for the construction of high walls may benefit from a long service life. For this purpose, it has been proposed a method of the type described above, wherein the mixture comprises at least silt earth, quicklime, and cement, to obtain said material. In particular, silt soil is used in an undetermined proportion, quicklime in a proportion of 2% to 3%, and cement in a proportion of 3% to 15%. However, the use of new processes for compacting the mixture, especially by vibration, has made it possible to determine new ranges of use for these components, the material then having high and unexpected resistance capacities. Also, according to this new design, the invention proposes a method of manufacturing at least one vertical earth-based wall of the type described above, characterized in that during the second step, a mixture is prepared which, at the very least, comprises : - clay loam and / or sandy earth in a proportion of 70 to 98%, - quicklime, natural or artificial, in a proportion of 1 to 10%, 25 - cement in a proportion of 1 to 15%. According to other characteristics of the invention: during the second step of preparation of the material, a mixture is prepared which additionally comprises fibers in a proportion of 0.1 to 15 kg per cubic meter of mixture; fibers comprise synthetic fibers, in particular polypropylene, 3 - the fibers comprise natural fibers, especially of flax or cotton, - the mixture is prepared according to a moisture content of 5 to 50%, to allow the air to to substitute for the water of the mixture during its evaporation, in order to confer a high thermal insulation capacity to the material once said material is dry, the moisture content of 5 to 50% is obtained in particular by adding in the second stage of preparation of the material, during the second stage of preparation of the material, a mixture comprising clayey and / or sandy loam soil is prepared in a proportion of 70 to 98% , e preferably: - quicklime in a proportion of 1 to 2% or in a proportion of 3 to 10%, - cement in a proportion of 1 to 2%, - fresh water in a proportion of from 5 to 25% or in a proportion of 35 to 50%, fibers in a proportion of 0.1 to 2 kg / m 3 or in a proportion of 12 to 15 kg / m 3; In the second step of preparing the material, a mixture is additionally provided with an air entrainer, making it possible to increase the quantity of air in the mixture in the form of fine stable and regular sized air bubbles uniformly distributed in the air. The mixture. during the second step of preparation of the material, a mixture is prepared which additionally comprises a plasticizer consisting of an acrylic polymer in liquid form, during the second step of preparation of the material, the mixture is produced at the same time; using a mixer, in particular a mobile mixer with horizontal or vertical axes allowing the mixing to be carried out on the same site where the wall is to be made, 4 - at the end of the sixth step of disassembling the formwork, it is sprayed on any free surface of the material, a curing product making it possible to oppose the evaporation of the water contained in the material, the process comprises at least one succession of series of steps each of which comprises at least the first, third and fourth step, to allow to mount the wall by successive filling and placement of the material in formwork elements stackable on top of each other, - the method comprises a at least one succession of series of steps each of which comprises at least a third and a fourth step, to enable the wall to be mounted by successive filling and placing of the material in monoblock formwork elements; the method comprises a step additional, interposed between the first and third steps, during which is introduced into the formwork element at least one load-reinforcing element of the wall, in particular a welded mesh reinforcement, 20 - the fourth step of setting up the material is made at least with the aid of a vibrating device, in particular a device for vibrating the shuttering element and / or at least one vibrating needle immersed in the mixture. Other features and advantages of the invention will become apparent on reading the detailed description which follows for the understanding of which reference will be made to the appended drawings in which: FIG. 1 represents a first embodiment of a third embodiment; step of the method of the invention implemented using the formwork according to the invention; FIG. 2 represents a first embodiment of a first embodiment of the fourth step of the method of the invention; FIG. 3 represents a first embodiment of a new third step of the method according to the invention; FIG. 4 represents a first embodiment of the sixth step of the method according to the invention; FIG. 5 represents a second embodiment of a fourth step of the method of the invention implemented at the use of the formwork according to the invention; FIGS. 6 and 7 show a second embodiment of new fourth steps for carrying out the method of the invention; FIG. 8 represents a second embodiment of the sixth step of the method according to the invention. In the following description, like reference numerals designate like or similar parts. The figures show the implementation of a method of manufacturing a vertical earth-based wall according to the invention. In known manner, such a method comprises at least a first step of preparing a substantially vertical formwork element determining the thickness of the wall to be made, a second step of preparing an earthy material, and successively at least a third step of filling the shuttering element with the material, at least a fourth step of placing the material, a fifth step of drying the material and a sixth step of disassembly of the formwork. A method of this type is commonly used in the manufacture of concrete walls. One of the drawbacks of concrete walls lies in the difficulty of their implementation on light construction sites, the concrete to be prepared beforehand and brought to the site.

Furthermore, once cast and hardened, the concrete can be difficult to work, which makes it unsuitable for example to build a particular house in which must be arranged a large number of openings.

The construction in "rammed earth", that is to say in clay simply compacted, is easier to implement, but rammed earth is not likely to allow the construction of walls of high height, or likely to support significant expenses. Moreover, rammed earth offers only a poor resistance to humidity. According to a known design, a new process has been proposed according to which, during the second step of preparation of the material, a mixture is prepared comprising at least the silt earth, 2 to 3% quicklime, and 3 to 5% cement, to obtain said material. The material thus obtained has the advantages of traditional rammed earth, since the silt soil base that is used allows the material to breathe well once said material has solidified. As a result, the material also has high thermal and sound insulation characteristics. It is also particularly effective in its ability to play a firewall role. The material thus obtained, however, is much more resistant than ordinary rammed earth, because the presence of quicklime makes it possible to absorb the moisture of the material and because the cement makes it possible to reinforce the cohesion of the material. However, the use, as will be seen in the remainder of this description, vibrating material tamping means of the material allows to use these components in ranges not yet known, which allow to confer the material characteristics of exceptional and unexpected resistance. Thus, the mixture forming the subject of the present invention comprises clay soil, sandy, or a mixture of these two types of earth in a proportion of 70 to 98%. In the case of the use of a clayey earth, and depending on the consistency and resistance that we want to give the wall to obtain, we can choose a fine clay loam soil, or a clay loam soil loaded with pebbles. The mixture also comprises quicklime in a proportion of 1% to 10% quicklime and cement in a proportion of 1 to 15% cement. As a variant of the process forming the subject of the invention, during the second step of preparing the material, a mixture is prepared comprising not only at least silt earth, quicklime, and cement, but also fibers in a proportion of 0.1 to 15 kg per cubic meter of mixture. The fibers can be of different types. According to a first variant of this second embodiment, the fibers comprise synthetic fibers, in particular polypropylene fibers. According to a second variant of this second embodiment, the fibers comprise natural fibers, in particular flax or cotton. Whatever the method of carrying out the process, whether or not the mixture is provided with fibers, it will be preferable to use a normal setting cement commercially available under the reference PORTLAND CPJ 45. This composition makes it possible to obtain a material offering a compressive strength of about 20 to 30 MPa, which allows, unlike traditional rammed earth, to make walls several meters high in a single application of the process. Part of the ranges of use of the aforementioned components are already known in the document F R-2935.008. However, the invention makes it possible to prepare a material according to ranges of use of components that are not known from the state of the art, with equal or greater resistance. Thus, it will be possible in particular to prepare a mixture comprising clay loam and / or sandy earth in a proportion of 70 to 98%, and preferably: - quicklime in a proportion of 1 to 2% or in a proportion of 3 to 10%, - cement in a proportion of 1 to 3% or 5 to 15%, - fresh water in a proportion of 5 to 25% or in a proportion of 35 to 50%, - fibers in a proportion of 0.1 to 2 kg / m3 or in a proportion of 12 to 15 kg / m3. The advantage of this material is that it can be prepared on the site where the wall is to be built. Thus, during the second step of preparation of the material, the mixing is carried out using a kneader, in particular a mobile kneader with horizontal or vertical axes carried in known manner by a tractor-type construction machine (no represent). Another particularly advantageous characteristic of the process which is the subject of the invention is that, whatever its mode of execution, during the second stage of preparation of the material, the mixture is prepared according to a moisture content of 5 to 50 %. This configuration allows the ambient air, as the material dries and the water it contains evaporates, to substitute for the water of the mixture. In this way, the air contained in the material imparts to said material, once dry, a high thermal insulation capacity.

Depending on the moisture content required in the mixture, one can either be content with the moisture naturally contained in the constituent components of the mixture, or obtain this moisture content by adding fresh water during the second preparation step of the material. Advantageously, during the second step of preparing the material, it is possible to add an air entrainer to the mixture, making it possible to increase the quantity of air in the mixture in the form of fine stable and regular-sized air bubbles. , evenly distributed in the mixture. It is also advantageous to add to the mixture a plasticizer consisting of an acrylic polymer in liquid form. According to a first embodiment of the method which has been represented in FIGS. 1 to 4, the manufacturing method preferably comprises at least one succession of series of stages each of which comprises at least the first, third and fourth stages, for allow to mount the wall by successive filling and placement of the material in formwork elements stackable on top of each other. To this end, as illustrated more particularly in FIGS. 1 and 3, on a floor or a slab 1 1, the formwork 10 comprises, in accordance with the invention, a stack of formwork elements each comprising at least one element 12 of inner vertical wall, maintained by at least one strut structure 14, and an outer vertical wall member 18, at least the outer vertical formwork elements 18 being successively added to one another as the climb proceeds; wall, that is to say during the third successive stages. As illustrated in FIG. 1, it is possible to place in advance all the elements 12 of the inner vertical wall, then successively the outer vertical formwork elements 18. This makes it possible to set up only one strut structure. 14, set up from the beginning of the operation. As a variant (not shown), it is possible to successively install in pairs the elements 12 of the inner vertical wall and the outer vertical formwork elements 18, but this makes it necessary to modify the strut structure 14 5 as and when as the stack of elements 12. The elements 12 of inner vertical wall thus form an inner wall 15 and the outer vertical formwork elements 18 thus form an inner wall 16. The walls 15 and 16 thus delimit between them a cavity 10 20. Preferably, the formwork 10 is thus made during a first step during which the wall 15 is put in place in its entirety and a vertical formwork element 18. Then the mixture is prepared during the second stage. As illustrated in FIG. 1, which represents a third initial step of the process of the invention, the material 22 is then introduced into the cavity 20. Then, as illustrated in FIG. 2, during a fourth process step the material 22 is preferably put in place. Preferably, according to a first embodiment of this fourth step, the material 22 is put in place at least with the aid of a vibrating device, in particular a setting device. in vibration of the shuttering element and of one or more vibrating needles 24 immersed in the mixture, as shown in FIG. 2. These needles are of the type of those commonly encountered on construction sites for effecting the vibration of concrete . According to a second embodiment of this fourth step (not shown) the introduction of the material 22 could be achieved using a pestle. This pestle could be manual or pneumatic. Of course, it will be understood that, alternatively, (not shown), the placement of the material could be achieved 2964991 II according to a combination of these two variants, that is to say both with the help of pestle and vibration. If the wall obtained is high enough, then we go to a fifth step during which the material is allowed to dry, then to a sixth step during which we remove the formwork 10. If the wall is not high enough at the end of the fourth installation step, an external vertical element 18 is added during a new first step of preparing the formwork 10. Each element 18 can be attached to the previous one by means of fasteners. 30. Then the material cavity 22 is filled again with a new third step, and then this material 22 is put back into place with the vibrating needle. The operation is then repeated until the desired wall height is obtained. From a given height, we can add to the formwork 10 a bridge 26 to circulate in height along the wall and perform the fourth stages of implementation. Finally, as illustrated in FIG. 4, in one embodiment as in the other, during a sixth step of disassembly of the formwork, the wall is released from the formwork 10. According to a second embodiment of FIG. 5 to 8, the manufacturing method preferably comprises at least one succession of series of steps, each of which comprises at least the first, third and fourth stages, to enable the wall to be mounted by filling and placing 30 in place successive material in fixed formwork elements. For this purpose, as illustrated more particularly in FIGS. 5 to 8, on a floor or a slab 1 1, the formwork 10 comprises 12 according to the invention an element 12 of internal vertical wall, maintained by at least one structure 14 forestay, and an outer vertical wall element 18, both monoblocs. As illustrated in FIG. 1, it is possible to place the inner vertical wall element 12 beforehand, then the outer vertical shuttering element 18. This makes it possible to set up only one strut structure. 14, set up from the beginning of the operation. The inner vertical wall element 12 thus has an inner wall 15 and the outer vertical shuttering element 18 thus has an inner wall 16. The walls 15 and 16 thus delimit between them a cavity 20. Preferably, the formwork 10 is thus performed during a first step, shown in Figure 5, during which it is put in place as previously explained the elements 12 and 18. Then the mixture is prepared in the second step.

The material 22 is then introduced into the cavity 20 during a third initial step of the process of the invention (not shown). As illustrated in FIG. 5, during a fourth initial stage of the process, it is in place the material 22.

Preferably, according to a first embodiment of this fourth step, the introduction of the material 22 is carried out at least with the aid of a vibrating device, in particular a device for vibrating the formwork element and one or more vibrating needles 24 immersed in the mixture, as shown in FIG. These needles are of the type that are commonly encountered on construction sites to achieve the vibration of concrete. According to a second embodiment of this fourth step (not shown) the introduction of the material 22 could be achieved using a pestle. This pestle could be manual or pneumatic.

Of course, it will be understood that alternatively, (not shown), the introduction of the material could be carried out according to a combination of these two variants, that is to say both with the aid of a pestle and vibration. If the resulting wall is high enough, then we go to a fifth step during which the material is allowed to dry, then to a sixth step, shown in FIG. 8, during which the formwork 10 is removed. is not high enough, at the end of the fourth placing step, the cavity 20 of material 22 is filled again according to a new third step (not shown), and then this material 22 is again put in place. Using the needle 24, as shown in Figure 6. As shown in Figure 7, the operation is then repeated until the desired wall height is obtained.

From a given height, it is possible to add as previously to the formwork 10 a bridge 26 to circulate in height along the wall and perform the fourth stages of implementation. Preferably, at the end of the sixth dismantling step of the formwork which has been shown in FIGS. 4 and 8, at least one free surface of the material which has been deconstructed is sprayed with a curing product making it possible to oppose the evaporation of the the water contained in the material. It will also be noted that the method could comprise an additional step, interposed between the first and third steps, during which the formwork element 10, that is to say in the cavity 20, is introduced into at least one element load reinforcement of the wall (not shown).

This load reinforcing element could consist of a welded mesh reinforcement similar to those used in pouring reinforced concrete. The invention thus makes it possible to erect high earth-based walls, for example walls three meters high and more, intended for individual dwellings, in a single "spoiled", that is to say in one application of the process. The walls thus obtained have high qualities of resistance while allowing a certain ventilation of the dwellings, by their breathable and insulating qualities. Moreover, the method of the invention makes it possible to raise such walls extremely rapidly, the material being able to be manufactured on the site of the construction site, which makes it possible to considerably reduce the manufacturing costs of a machine. individual dwelling or a work of another type.

Claims (15)

REVENDICATIONS1. A method of manufacturing at least one vertical earth-based wall, comprising at least a first step of preparing a substantially vertical formwork element (12, 18) determining the thickness of the wall to be produced, a second step of preparing an earth material (22) during which a mixture is prepared comprising at least silt soil, quicklime, and cement, to obtain said material, and successively at least a third step of filling a cavity (20) of the formwork member (12, 18) with the material, at least a fourth step of placing the material, a fifth step of drying the material and a sixth step of dismantling of the formwork (10), characterized in that during the second step, a mixture is prepared comprising at least: - silt clay, clay and / or sand, in a proportion of 70 to 98%, - quicklime, natural or artificial, in a proportion of 1 to 10%, - cement in a proportion of 1 to 15%. 2. The manufacturing method according to the preceding claim, characterized in that during the second step of preparing the material (22), is prepared a mixture further comprising fibers in a proportion of 0.1 to 15 kg per meter mixing cube. 3. Manufacturing process according to claim 2, characterized in that the fibers comprise synthetic fibers, in particular polypropylene. 4. Manufacturing process according to claim 2, characterized in that the fibers comprise natural fibers, in particular flax or cotton. 5. Manufacturing process according to any one of the preceding claims, characterized in that the mixture is prepared according to a moisture content of 5 to 50%, to allow air to be substituted for the water of the mixture. during its evaporation, in order to confer a high thermal insulation capacity to the material once said material is dry. 6. Manufacturing process according to the preceding claim, characterized in that the moisture content of 5 to 50% is obtained in particular by adding fresh water during the second stage of preparation of the material. 7. Method according to claim 6, characterized in that during the second step of preparing the material (22), is prepared a mixture comprising clay loam soil and / or sandy in a proportion of 70 to 98% and preferably: - quicklime in a proportion of 1 to 2% or in a proportion of 3 to 10%, - cement in a proportion of 1 to 3% or in a proportion of 5 to 15 %, - fresh water in a proportion of 5 to 25% or in a proportion of 35 to 50%, 20 - fibers in a proportion of 0.1 to 2 kg / m3 or in a proportion of 12 at 15 kg / m3. 8. Manufacturing process according to any one of the preceding claims, characterized in that during the second step of preparation of the material (22), a mixture is prepared further comprising an air entrainer, allowing increase the amount of air in the mixture in the form of fine stable and regular sized air bubbles uniformly distributed in the mixture. 9. A manufacturing method according to any one of the preceding claims, characterized in that during the second step of preparing the material (22), a mixture is prepared further comprising a plasticizer consisting of an acrylic polymer under liquid form. 17 10. The manufacturing method according to any one of the preceding claims, characterized in that during the second step of preparing the material (22), the mixture is produced using a kneader, including a mobile kneader. with horizontal or vertical axes allowing the realization of the mixture on the same site where the wall must be made. 11. Manufacturing process according to any one of the preceding claims, characterized in that after the sixth step of disassembly of the form, is sprayed on any free surface of the material a cure product to oppose to the evaporation of the water contained in the material. 12. Manufacturing process according to any one of the preceding claims, characterized in that it comprises at least one series of series of steps each of which comprises at least the first, third and fourth stages, to allow mounting the wall. by successive filling and placing of the material (22) in formwork elements (12, 18) stackable (10) on top of one another. 13. Manufacturing process according to any one of the preceding claims, characterized in that it comprises at least one succession of series of steps each of which comprises at least a third and a fourth step, to allow mounting the wall by successive filling and placing of the material (22) in monoblock formwork elements (12, 18). 25 14. Manufacturing method according to one of the preceding claims, characterized in that it comprises an additional step, interposed between the first and third steps, during which is introduced into the element (12, 18) formwork ( 10) at least one load-reinforcing element of the wall, in particular a welded mesh reinforcement. 15. Manufacturing process according to any one of the preceding claims, characterized in that the fourth step of placing the material is carried out at least with the aid of a vibrating device, in particular a device for vibrating the material. shuttering element and / or at least one vibrating needle immersed in the mixture.