FR3016377A1 - IMPROVEMENT TO A PROTECTIVE COATING BASED ON EARTH - Google Patents

Abstract

The invention provides a coating coating of a vertical wall, in particular interior or exterior coated with cement, characterized in that it comprises at least one mixture comprising: - fresh water (25), - soil natural (12), in a mass proportion of 70 to 98%, - quicklime (14), obtained by thermolysis of limestone, mainly consisting of calcium oxide (CaO), in a mass proportion of 1 to 10% - Cement (22) and / or artificial lime (20), in a mass proportion of 1 to 15%, - Fibers (16) full lengths of between 1 and 10 cm, in a proportion of 0.1 to 20 kg per m 3 of mixture, characterized in that the mixture (18) comprises aggregates whose size is less than or equal to 10 mm, in a mass proportion of 10 to 50% of the mixture (18).

Description

The invention relates to an improvement to a coating coating for a vertical wall, in particular an interior or exterior coating comprising cement. The invention relates more particularly to an improvement to a coating coating of a vertical wall, in particular an inner or outer coating comprising a mixture comprising - fresh water, - natural earth, clay and / or sand, in a mass proportion of 70 to 98%, - quicklime, obtained by thermolysis of limestone, mainly consisting of calcium oxide (CaO), in a mass proportion of 1 to 10%, - cement or artificial lime, in a mass proportion of 1 to 15%, solid fibers of lengths between 1 and 10 cm, in a mass proportion of at most 1%. The use of plaster for the internal or external lining of vertical walls has been known for a long time. 20 One of the oldest types of plaster, still used today in some Mediterranean countries, is to use raw earth mixed with lime and possibly straw to cover the walls. The disadvantage of this design is that it can only be reserved for hot countries. In fact, any earth contains clay which can only be stabilized by quicklime treatment, which, for the record, results from the calcination of ordinary lime. In the absence of quicklime, the clay contained in the earth of such a mixture can not be stabilized. Such a coating is therefore vulnerable to rains that can dissolve the clay. On the contrary, the use of quicklime reduces the amount of clay present in the earth, just as it helps to reduce the moisture of the coating.

Furthermore, in a conventional coating, the use of straw as a binder makes it possible to obtain only a mediocre reinforcement of the coating to which it is mixed, and makes it possible to obtain only a coarse appearance. , incompatible with a high level of finish. Indeed, the straw appears in effect in a tubular aspect, and as such, besides being particularly brittle, it is moreover eminently unsightly. To overcome these drawbacks, FR-A1-2.988.751 proposed a new earth-based coating material of the type described above, comprising fibers to increase its performance. Nevertheless, under certain drying conditions, there are problems of cracking of the coating, which complicates its implementation and requires in particular the taking of particular precautions during drying. Now, surprisingly and unexpectedly, the addition of aggregates to the mixture makes it possible to remedy the problems of cracking. The invention provides an improvement of such a coating for its implementation in all conditions. For this purpose, the invention provides a coating of the type described above comprising aggregates. For this purpose, the invention provides a coating of the type described above, characterized in that the mixture comprises aggregates whose size is less than or equal to 10 mm, said aggregates representing a mass proportion of 10 to 50% of the mixture. According to other characteristics of the coating: - the aggregates consist of: - natural aggregates, in particular sand and / or gravel, and / or - recycled aggregates, in particular crushed concrete, - the mixture comprises at least one adjuvant among: - a plasticizing agent, in a mass proportion of at most 3%, in particular a polymer, especially of polycarboxylate type, - a water-repellent agent, in a mass proportion of at most 5%, in particular a powder of stearate type, - a fungicidal agent, in a mass proportion of at most 2%, - a rheological maintenance agent, in a mass proportion of at most 2%, in particular a composition based on polymers, - a binder additive in a mass proportion of at most 10%, consisting of a pozzolanic additive, in particular a metakaolin obtained by calcining kaolin and / or kaolin clay, an anti-shrinkage agent in a mass proportion of at most 5 %, in particular based on calcium sulphate associated with n ether glycol, - a water retaining agent in a mass proportion of at most 2%, especially based on cellulose, - an ocher dye in a mass proportion of at most 5%, - a synthetic resin in a mass proportion of at most 5%, in particular based on styrene butadiene, the fibers are natural solid fibers, in particular of flax or cotton, the fibers are synthetic solid fibers, in particular polypropylene, the mixture is prepared according to a mass moisture content of 5 to 35% to allow the air to replace the water of the mixture during its evaporation, in order to confer a high thermal insulation capacity to the coating once said plaster is dry. The invention also proposes a method of manufacturing a coating coating comprising at least one mixture comprising at least: - fresh water, - natural, clay and / or sandy earth, in a mass proportion of 70 98%, - quicklime, obtained by thermolysis of limestone, mainly consisting of calcium oxide (CaO), in a mass proportion of 1 to 10%, - cement or artificial lime in a mass proportion from 1 to 15%, solid fibers with lengths of between 1 and 10 cm, in a mass proportion of at most 1%, said process comprising at least a first mixing step during which a mixture comprising at least the natural earth, the quicklime and the fibers according to a humidity level or natural hygrometry of 10 to 20%, the cement 20 being kept separately from moisture, then a final second stage occurring immediately before use of the sleeve t, during which the cement and the water are added to said mixture, characterized in that it comprises a first additional step during which at least one of the components of said mixture is added aggregates whose size is less than or equal to 10 mm, the aggregates being dosed so that they represent a mass proportion of 10 to 50% of the final mixture. According to another characteristic of this manufacturing process, said method comprises a second additional step during which at least one of the components of said mixture is added an adjuvant among: a plasticizer, a water-repellent agent, a fungicidal agent, a rheological maintenance agent; a pozzolanic additive forming a binder, an anti-shrinkage agent, a water-retaining agent, a tinting ocher, a synthetic resin. Finally, the invention proposes a method of application to a support for a coating coating of the type described above, characterized in that it comprises at least one step during which the coating is manually spread on the support. In a variant, the invention also proposes a method of applying to a support a coating coating of the type described above, characterized in that it comprises at least one step of pumping the coating through a coating. led and at least one projection step of the coating exiting said conduit on the support. 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 the first stage of manufacture of the coating according to FIG. 2 represents an intermediate stage of storage and / or transport of the coating according to the invention; FIG. 3 represents the second stage of manufacture of the coating according to the invention; FIG. 4 represents a first step of a preferred process for applying the coating according to the invention; FIG. 5 represents a second step of a preferred method of applying the coating according to the invention.

In the following description, like reference numerals designate like parts or having similar functions. The figure shows the first step of manufacturing a coating according to the invention. The coating is in particular an interior or exterior coating and it comprises at least one mixture comprising conventionally - fresh water, - natural earth, in a mass proportion of 70 to 98%, - quicklime, obtained by thermolysis of limestone, mainly consisting of calcium oxide (CaO), in a mass proportion of 1 to 10%, - cement and / or artificial lime, in a mass proportion of 1 to 15%, - solid fibers of lengths between 1 and 10 cm, in a mass proportion of at most 1%, ie substantially 0.1 to 20 kg per m 3 of mixture.

Such a coating gives overall satisfaction compared to a traditional coating. However, it has been found in certain drying conditions shrinkage or cracking phenomena that require the use of the coating restrictively.

One solution to overcome these disadvantages is to increase the particle size of the mixture. It has indeed been found that, surprisingly and unexpectedly, the addition of aggregates of defined cut made it possible to avoid the phenomena of cracking.

Also, the invention provides a coating coating of the type described above, characterized in that the mixture comprises aggregates whose size is less than or equal to 10 mm, said aggregates representing a mass proportion of 10 to 50% of the mixture.

More specifically, the natural earth may be clay soil or natural soil of the sandy soil, or a mixture of both types of soil. The fibers are solid fibers, that is to say that they have a structure devoid of cavity. As such, they have a much higher resistance to tubular elements, synthetic or natural as straw. The fibers are typically of the type commonly used in the textile industry or in the building industry. It may be natural fibers, especially linen or cotton, or synthetic solid fibers, especially polypropylene. The cement is preferably a commercially available normal setting cement. Artificial lime, by definition, essentially comprises calcium and magnesium oxide (CaO, MgO) and / or calcium and magnesium hydroxide (Ca (OH) 2, Mg (OH) 2 ). When used in the mixture, artificial lime can be added as a partial or total replacement of the cement. Aggregates can be of two types. These may be natural aggregates, such as sand and / or gravel, or recycled aggregates, such as concrete or crushed mortar. Of course the different types of aggregates can be mixed and combine natural or recycled aggregates, in varying proportions. Furthermore, it is possible to advantageously incorporate in the mixture one or more adjuvants which advantageously make it possible to limit the phenomena of shrinkage or cracking even more effectively. Thus, the mixture may furthermore comprise a plasticizer, in a mass proportion of at most 3%, in particular a polymer, especially of polycarboxylate type. The mixture may also comprise a water-repellent agent, in a mass proportion of at most 5%. %, in particular a stearate-type powder. The mixture may also comprise a fungicidal agent, in a mass proportion of at most 2%. The mixture may also comprise a rheological maintenance agent, in a mass proportion of at most 2%, in particular a composition based on polymers. The mixture may also comprise a binder additive in a mass proportion of at most 10%. Preferably, such an additive will consist of a pozzolanic additive, especially a metakaolin obtained by calcining kaolin and / or kaolinic clay. The mixture may also comprise an anti-shrinkage agent in a mass proportion of at most 5%, especially based on calcium sulphate combined with a glycol ether. The mixture may also comprise a water-retaining agent 15 in a proportion mass of not more than 2%, in particular based on cellulose. This agent makes it possible to slow the drying and thus reduces the risks of cracking. The mixture may also comprise an ocher dye in a mass proportion of at most 5%. The mixture may finally comprise a synthetic resin in a mass proportion of at most 5%, especially a styrene-butadiene-based resin. Preferably, the coating prior to use should have a moisture content of 5 to 35%, to allow air to be substituted for the water of the mixture as it is evaporated, in order to provide a water absorption capacity. high thermal insulation to the coating once said coating is dry. The coating thus obtained has the external advantages of a traditional earthy mixture, such as "rammed earth", because the natural earth base which is used allows good breathing of the material 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 is however much more resistant than ordinary plaster, because the presence of quicklime makes it possible to absorb the moisture of the material and because the fibers and the cement make it possible to reinforce the cohesion of the material.

The coating can be made immediately before use. However, according to a preferred method of the invention, the coating is carried out in two steps, namely a first step after which the mixture is prepared to be bagged for transport and / or storage and a second step during which the mixture is finalized prior to its use. Then, the manufacturing process of the coating according to the invention comprises a first mixing step during which a mixture is made comprising at least the amended natural earth, quicklime, and the fibers according to a moisture content. or natural hygrometry of 10 to 20%. As illustrated in FIG. 1, in the context of an industrial production, the mixer is blended at the factory with a mixing device 19 for mixing 20 with natural earth 12, in a mass proportion of 70 to 98% of the mixture. final to obtain, - quicklime 14, obtained by thermolysis of limestone, mainly consisting of calcium oxide (CaO), in a mass proportion of 1 to 10%, 25 - full fibers 16 of lengths between 1 and cm, in a mass proportion of at most 1%, ie from 0.1 to 20 kg per m 3 of mixture. The artificial lime 20 and / or the cement 22, dosed separately in a mass proportion of 1 to 25% of the mixture, are in turn kept separately from moisture. As illustrated in FIG. 2, the mixture 18 is then bagged in a bag 24, artificial lime 20 and / or cement 22 in at least one bag 26, which can be placed outside or inside the bag. bag 24, the dose of artificial lime 20 and / or cement 22 corresponding to the mixing dose 18. The bag 24 and the bag 26 can then be stored or transported one inside the other or separately.

Then there intervenes a second final step, immediately preceding the use of the coating, during which the bag 24 and the bag 26 are opened by mixing their contents. For example, in a tank 23, the mixture 18 from the bag 24 is mixed with the artificial lime 20 and / or the cement 22 from the bag 26. Water 25 is optionally incorporated into it to obtain a mixture 18 having a final moisture content of 5 to 35%. According to the invention, the method according to the invention also comprises a first additional step (not shown) during which at least one of the components of said mixture is added aggregates 25 whose size is less than or equal to 10 mm. the aggregates being dosed so that they represent a mass proportion of 10 to 50% of the final mixture. This first step may occur prior to the first step, during the first step, or even during the second final step, without limitation of the invention. If the addition takes place before the first step or during the first step, the aggregates can be added to at least 25 components of the bag 24 or bag 26. The dosage must in any case be performed so that the aggregates added to the mixture represent a mass proportion of 10 to 50% of the final mixture. According to the invention, the process according to the invention also comprises a second additional step during which at least one of the components of said mixture is added an adjuvant 21 from one or more adjuvants 21 mentioned above, namely less an adjuvant among a plasticizer, a water repellent, a fungicidal agent, a rheological maintainer, a pozzolanic additive binder, an anti-shrink agent, a water retaining agent, an ocher dye, and a synthetic resin .

In the same way as above, this second additional step can take place before the first step, during the first step, or even during the second final step, without limitation of the invention. If the addition takes place before the first step or during the first step, the adjuvants can be added to at least one of the components used in the composition of the bag 24 or the bag 26. FIG. 1 illustrates, by way of example and in a nonlimiting manner of the invention, a particular embodiment in which the aggregates 25 and at least one adjuvant 21 are added in the mixer 10, but it will be understood that this mode of implementation of the process is not limiting of the invention. In particular, the adjuvant 21 could be added to the cement 22. Furthermore, according to the invention, a first application method (not shown) of the coating on a support such as a wall comprises at least one step during from which the coating is spread manually on the support, for example with a trowel and a trowel. Figure 4 illustrates, alternatively, a first step of a second preferred method of application (not shown) of the coating on a support such as a wall. As illustrated in FIG. 4, this second preferred method comprises at least one step of pumping the coating mixture 18 through a pipe 30 and at least one step of projecting under pressure the coating coming out of said pipe 30 on the support 40. Thus, for example, the coating 18 is disposed in a tank 28. The coating is sucked by a pump 30 and pumped into a pipe 32 which ends with a lance 34 held by an operator 36, which thus projects the mixture 18 on a wall 40. Then, as shown in Figure 5, the operator 36 smooths the coating with a smoothing 38 and the coating is dried.

It will be understood that the coating can also be misted on the wall or projected in the manner of a plaster. It will also be understood that the coating is not necessarily smoothed. It can indeed be put in drying without smoothing to keep it an irregular appearance.

The walls thus covered with the coating according to the invention have high qualities of resistance while allowing a certain ventilation of the dwellings, by their breathable and insulating qualities.

Claims (10)

REVENDICATIONS1. Coating coating of a vertical wall, in particular an interior or exterior coating comprising a mixture (18) comprising: - fresh water (25), - natural earth (12), clay and / or sand, in a proportion mass of 70 to 98%, - quicklime (14), obtained by thermolysis of limestone, mainly consisting of calcium oxide (CaO), in a mass proportion of 1 to 10%, - cement (22) or artificial lime (20) in a mass proportion of 1 to 15%, - fibers (16) full lengths of between 1 and 10 cm, in a mass proportion of at most 1%, characterized in that the mixture (18) comprises aggregates whose size is less than or equal to 10 mm, said aggregates representing a mass proportion of 10 to 50% of the mixture (18). 2. Coating coating according to the preceding claim, characterized in that the aggregates consist of: - natural aggregates, including sand and / or gravel, and / or - recycled aggregates, including crushed concrete. 3. Coating coating according to the preceding claim, characterized in that the mixture (18) comprises at least one adjuvant (21) among: - a plasticizer, in a mass proportion of at most 3%, including a particular polymer of polycarboxylate type, - a water-repellent agent, in a mass proportion of at most 5%, in particular a stearate-type powder, - a fungicidal agent, in a mass proportion of at most 2%, - a rheological maintenance agent in a mass proportion of at most 2%, in particular a composition based on polymers, - a binder additive, in a mass proportion of at most 10%, consisting of a pozzolanic additive, especially a metakaolin obtained by calcination kaolin clay and / or cleaved kaolin clay, - an anti-shrinkage agent in a mass proportion of at most 5%, especially based on calcium sulphate combined with a glycol ether, - a water retaining agent in a mass proportion of not more than 2%, in particular cellulose, - a dyeing ocher in a mass proportion of at most 5%, - a synthetic resin in a mass proportion of at most 5%, especially based on styrene butadiene. 4. Coating coating according to one of claims 1 to 3, characterized in that the fibers (16) are natural full fibers, including linen or cotton. 20 5. Coating coating according to one of claims 1 to 3, characterized in that the fibers (16) are synthetic solid fibers, in particular polypropylene. 6. Coating plaster according to any one of the preceding claims, characterized in that the mixture is prepared according to a mass moisture content of 5 to 35% 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 coating once said coating is dry. 7. A method of manufacturing a coating plaster 30 comprising at least one mixture (18) comprising at least: - fresh water (25), - natural earth (12), clay and / or sandy, in a mass proportion of 70 to 98%, - quicklime (14), obtained by thermolysis of limestone, mainly consisting of calcium oxide (CaO), in a mass proportion of 1 to 10%, - cement (22%). ) or artificial lime (20) in a mass proportion of 1 to 15%, - fibers (16) full lengths of between 1 and 10 cm, in a mass proportion of at most 1%, said process comprising at least at least a first mixing step during which a mixture (18) lo comprising at least the natural earth (12), the quicklime (14) and the fibers (16) is prepared according to a humidity or natural humidity level of 10 to 20%, the cement (22) being kept separately from moisture, then a final second step immediately taking place before use of the coating, during which the cement (22) and the water (25) are added to said mixture (18), characterized in that it comprises a first additional step during which it is added to at least one of the components of said mixture of aggregates whose size is less than or equal to 10 mm, the aggregates being dosed so that they represent a mass proportion of 10 to 50% of the final mixture (18). 8. Manufacturing process according to the preceding claim, characterized in that it comprises a second additional step during which is added to at least one of the components of said mixture (18) an adjuvant (21), among: a plasticizer , a water repellant, a fungicidal agent, a rheological maintainer, a binder pozzolanic additive, an anti-shrink agent, a water retaining agent, a tinted ocher, a synthetic resin. 9. A method of applying to a support a coating coating according to one of claims 1 to 6, characterized in that it comprises at least one step during which the coating is manually spread on the support. 10. A method of coating a substrate with a coating according to one of claims 1 to 6, characterized in that it comprises at least one step of pumping the coating through a conduit (32). ) and at least one step of projecting the coating exiting said duct (32) on the support (40).