Earth-based mortar spraying machine

Description

Scope of the invention

[0001] The present invention relates to a method for projecting an earth-based mortar, a projecting machine and a kit for a projecting machine. State of the art

[0002] In the context of evolving regulations, it is now mandatory in the construction sector to consider the environmental impact of the materials used. Consequently, we are witnessing a considerable evolution in construction techniques with the use of new, more environmentally friendly materials. However, to ensure widespread adoption, any new technology must not only offer good performance but also be easy to implement and inexpensive.

[0003] This demand is still far from being met today, and the demand for new technologies better suited to building professionals is still strongly felt.

[0004] In the construction industry, premixed plasters have long been used to coat masonry structures. These plasters, which are mixed from a powder form, are applied directly to the masonry by spraying. Such plasters have a relatively rapid hardening capacity, as they are primarily gaseous in composition with varying amounts of additives to enhance their properties. This mechanical application of plaster to walls is particularly advantageous because it significantly reduces the manual labor required by masons. This benefit has led to the widespread adoption of plaster spraying machines, which are capable of mixing, pumping, and then spraying the plaster onto a building's surface.

[0005] The document entitled "Technical Implementation Document (DTMO) applicable to the application of plaster or pointing in restoration, using traditional 100 NHL 5 lime mortar with a screw or piston plaster sprayer" by Laurent Tedeschi, dated August 24, 2018, discloses a plaster sprayer equipped with a screw pump for traditional T25 mortars with a 30 m hose and a compressed air line. FR 3 016 377 A1 discloses a method for spraying an earth-based mortar with a plaster sprayer, which method includes the following steps: i) preparation of the earth-based mortar; ii) pouring the mixture, at the end of step i), into a loading hopper which is fixed to the frame of the spraying machine, iii) pumping the mixture through an opening in this same loading hopper, by a sparrow pump and injecting this mixture into a pipe extending from said pump; and iv) spraying, towards a surface, the mixture at the end of the pipe by a lance ending in a nozzle.

[0006] The online Turbosol documentation: "POLI T Screw Pump", dated February 2029 (URL:https: / / www.bmssolutions.fr / wp-content / uploads / 2020 / 11 / POLI-T-2019-FRA-Gennaio-PDF-WEB.pdf) discloses a spraying machine comprising a loading hopper fixed to its frame, a spout pump connected to an orifice of this same hopper, which allows the pumping and injection of the mixture into a pipe extending from said pump; and at the end of the pipe, a lance terminating in a nozzle, in which: The Moor pump does not have a jacket for spraying single-layer plaster but a jacket for liquid screed or a jacket for traditional mortar, and also includes a compressed air line opening at the end of the nozzle to allow spraying earth-based mortar onto the surface. Summary of the invention

[0007] The inventors have developed a new material that could replace concrete: an earth-based mortar. In addition to its mechanical and thermal properties, this material has the advantage of being sprayable onto vertical surfaces, which simplifies its application and therefore reduces associated costs.

[0008] The inventors have now been able to project this earth-based mortar using conventional plaster spraying machines with a few modifications to these machines.

[0009] Consequently, a first object of the invention relates to a method for projecting an earth-based mortar with a projection machine, which method comprises the steps of: (i) preparation of earth-based mortar by mixing: (ia) earth from earthmoving or excavation operations (quarry), or crushed deconstruction materials (concrete, brick, plaster, stone, and mortar), excluding topsoil, with a particle size of 20 mm or less, preferably 15 mm or less, in a volume proportion of 20 to 55%, preferably 25 to 50% and, particularly preferably, 20 to 40%; (ib) a binder comprising slag or metakaolin and, possibly, lime, in a volume proportion of 15 to 55%, preferably 25 to 50%;(ic) a material having a silica content greater than 50% (by weight), an open porosity greater than 45% as measured by mercury intrusion porosimetry, a particle size less than or equal to 5 mm, preferably 2 mm, and in a volume proportion of 0 to 25%, or even 2 to 25%, preferably 3 to 20% and, particularly preferably, 4 to 18%, for example 4 to 10%; (id) aggregates having a particle size between 2 and 20 mm, and in a volume proportion of 0 to 20%; (ie) fibres in a volume proportion of between 0 and 30%, preferably between 10 and 30% and, particularly preferably, between 10 and 20%; if) of the crystallizer in a volume proportion of between 0 and 15%, or even between 0.1 and 15%, for example between 0.3 and 10% or even between 1 and 8%, preferably between 1 and 4%; and particularly preferably between 2 and 4%;and ig) water in a volume proportion of between 5 and 20%, preferably between 5 and 10%. ii) discharge of the mixture, at the end of step i), into a loading hopper which is fixed to the frame of the spraying machine, iii) pumping of the mixture through an opening of this same loading hopper, by a small pump and injection of this mixture into a pipe extending from said pump; and iv) projection, towards a surface, of the mixture at the end of the pipe by a lance ending in a nozzle, preferably a vertical surface where: the small pump does not have a jacket for spraying single-layer plaster (e.g. type 2L6 or 2R6) but a jacket for liquid screed (e.g. type 60 / 12 or T25) or of traditional mortar type (e.g. 2L7);The piping, if less than 10 meters long, has an internal diameter of approximately 35 mm, or, if more than 10 meters long, an internal diameter of approximately 50 mm at the outlet of the small pump and an internal diameter of approximately 35 mm over its last 10 meters; a projection lance body with an internal diameter of approximately 35 mm and a nozzle with a diameter between 16 and 22 mm; a compressed air line opening at the end of the nozzle to allow the projection of the earth-based mortar onto the surface.

[0010] Advantageously, step i) of mixing is carried out in a mixing container of the spraying machine, which mixing container is capable of pivoting around a horizontal tilting axis around the frame so as to allow the mixture to be poured into the loading hopper.

[0011] Advantageously, the process according to the invention allows up to 14m³ of earth-based mortar to be projected per day.

[0012] Advantageously, step iii) of pumping the mixture through an orifice of this same loading hopper, by a sparrow pump and injection of this mixture into a pipe extending said pump is carried out at a pressure between 8 and 18 bars, preferably between 10 and 12 bars (1 bar = 0.1 MPa).

[0013] A second object relates to a machine capable of projecting an earth mortar according to the process defined previously, which includes a loading hopper fixed to the frame of the projecting machine, a small pump connected to an orifice of this same hopper and which allows the pumping and injection of the mixture into a pipe extending from said pump; and at the end of the pipe, a lance ending in a nozzle, where: The sparrow pump does not have a jacket for spraying single-layer plaster (e.g., type 2L6 or 2R6) but a jacket for liquid screed (e.g., type 60 / 12 or T25) or for traditional mortar (e.g., 2L7); the piping, if it is less than 10 meters long, has an internal diameter of approximately 35 mm or, if it is more than 10 meters long, an internal diameter of approximately 50 mm at the sparrow pump outlet and an internal diameter of approximately 35 mm over its last 10 meters; and also includes: a spray lance body with an internal diameter of approximately 35 mm with a nozzle having a diameter between 16 and 22 mm, a compressed air line opening at the end of the nozzle to allow the spraying of the earth-based mortar onto the surface.

[0014] A third item concerns a kit for a projection machine comprising: a jacket for liquid screed (e.g., type 60 / 12 or T25) or for traditional mortar (e.g., 2L7); a spray lance body with an internal diameter of approximately 35 mm and a nozzle with a diameter between 16 and 22 mm; a compressed air line opening at the end of the nozzle to allow the projection of the earth-based mortar onto the surface; a pipe, if it is less than 10 meters long, has an internal diameter of approximately 35 mm or, if it is more than 10 meters long, an internal diameter of approximately 50 mm at the outlet of the pump and an internal diameter of approximately 35 mm over its last 10 meters. Detailed description of the invention

[0015] A sparrow pump is a pump consisting of a helical rotor rotating inside a helical stator. The rotor, usually made of stainless steel, is machined with high precision, while the stator, called the jacket, is molded from an abrasion-resistant elastomer.

[0016] The geometry and dimensions of these parts are such that when the rotor is inserted into the stator, a double chain of sealed cavities is formed. As the rotor rotates inside the stator, the cavities progress along the pump axis in a spiral without changing shape or volume, thus transferring the product from the suction inlet to the discharge outlet.

[0017] The universally widespread facade spraying machines are eccentric screw pumps with a jacket for spraying single-layer coating of type 2L6 or 2R6 which can be found on machines of type S5, SP5, SP11 from PUTZMEISTER, S8, S28R, S38 from BUNKER, PH9B or PH9B-R from LANCY, Talent DMR from TURBOSOL.

[0018] The volume proportion of each component corresponds to the volume occupied by that component relative to the total volume of the mortar mixture.

[0019] Mortar is understood to mean both a coating, which can be applied to a surface and has a resistance of at least 5 MPa, a mounting or filling mortar with a resistance of at least 10 MPa, and a mortar intended for the manufacture of a load-bearing wall with a resistance of at least 15 MPa.

[0020] The process according to the invention can therefore allow the creation of both a coating and a wall.

[0021] Advantageously, the mortar prepared by the process according to the invention comprises cement in a volume proportion less than or equal to 5%, preferably less than or equal to 1% and, particularly preferably, a volume proportion less than 0.5% of cement, or even 0% of cement.

[0022] The environmental impact of the process according to the invention is therefore much less than that of existing processes which generally use at least 10% cement.

[0023] Soil refers to soil resulting from earthmoving or excavation operations (quarry), or crushed deconstruction materials (excluding topsoil).

[0024] Deconstruction material includes concrete, plaster, stone, and mortar.

[0025] Advantageously, the soil is chosen from the group including soil from earthmoving or excavation operations (quarry).

[0026] This soil can therefore exhibit a very wide diversity of composition depending on its origin. It may contain gypsum, silt, limestone, silica, clay, or even a mixture thereof. Preferably, this soil will have a clay content of 50% by weight or less, preferably 25% or less, and, even more preferably, 10% or less. This clay content can be determined using a particle size analysis method such as that described in standard NF X31-107.

[0027] Now, the soil does not come from sand quarries or aggregate quarries (virgin aggregates).

[0028] Furthermore, it is preferable to use clay that has undergone no more than one pretreatment by grinding, sorting (e.g., according to color), sieving, and / or drying before being mixed with the other components of the clay mortar. Now, the clay used in the mortar according to the invention has not undergone any sorting or sieving to remove particles with a size between 10 and 20 mm, preferably between 10 and 15 mm. It should be noted that the clay used has therefore not undergone any chemical pretreatment, such as pretreatment with a surfactant, to modify its structure and allow its liquefaction.

[0029] Prior to using any soil, care will be taken to determine the presence or absence of traces of metallic elements (Pb, As, etc.) in order to prevent any contamination.

[0030] Advantageously, the soil used in the process according to the invention will have a particle size less than or equal to 10 mm, preferably less than or equal to 6 mm.

[0031] Obtaining soil with a desired particle size from such a diversity of sources will generally require, in addition to determining the particle size of the soil, a sieving operation.

[0032] According to a preferred embodiment, the process according to the invention will therefore preferably include a soil sieving step prior to step i).

[0033] The very high adaptability of the process according to the invention to the different types of soil existing allows it to use the soil of the very site on which the process is implemented.

[0034] According to another preferred embodiment, the process according to the invention will preferably include a step prior to step i) of extracting the soil and, optionally, sieving it.

[0035] Slag refers to the waste products formed during the melting or processing of metal in liquid form. It is a mixture composed primarily of silicates, aluminates, and lime with various metallic oxides, excluding iron oxides.

[0036] Dairy will preferably be used in a volume proportion of between 10 and 40%, preferably between 10 and 30%.

[0037] Metakaolin refers to the product of the calcination of kaolin and / or kaolinitic clay.

[0038] Preferably, the binder includes slag and, possibly, lime.

[0039] Lime will preferably be used in a volume proportion of between 0 and 25%, preferably between 1 and 25%, for example between 5 and 20%, and particularly preferably between 10 and 20%.

[0040] By lime, we mean artificial lime which essentially consists of calcium and magnesium oxide and / or calcium and magnesium hydroxide.

[0041] Advantageously, lime is chosen from the group including hydraulic lime and air lime.

[0042] Preferably, hydraulic lime should be used, which preferably does not contain cement.

[0043] Preferably, NHL 3.5 or NHL 5 hydraulic lime should be used.

[0044] Preferably, NHL 3.5 Z or NHL 5 Z hydraulic lime should be avoided, as it contains cement.

[0045] Advantageously, the porous and silica-rich material is chosen from the group including diatomaceous earth, glass or rock wool waste (e.g., calcine and fibers), refractory brick waste (e.g., dust and residues).

[0046] Preferably, the silica-rich porous material used in the mortar according to the invention is diatomaceous earth. This is also known as kieselguhr. It is a siliceous sediment with very high porosity, giving it significant liquid absorption properties. The presence of such a porous material in the mortar advantageously allows for adjusting the water content and improves the performance of the resulting material.

[0047] Glass wool or refractory brick waste, when ground up, are also porous materials rich in silica which notably help to strengthen the binding function of mortar.

[0048] Advantageously, the particle size of this material is less than 1 mm. Typically, this particle size ranges from 1 to 500 µm.

[0049] Preferably, the porous, silica-rich material has a silica content greater than 80% (by weight) and, particularly preferably, greater than 90%.

[0050] A porous material is a material containing small pores or cavities that can hold one or more fluids (liquid or gas). A structure is said to have open porosity when the pores are interconnected, forming very fine channels. Such an open-porosity structure allows for water absorption.

[0051] A silica-rich material is defined as one with an open porosity greater than 45%. Porosity is a physical quantity ranging from 0 to 100% (or from 0 to 1) that determines a substrate's flow and retention capacity. This open porosity is classically measured using mercury intrusion porosimetry, a method that involves forcing mercury into the pores of a sample under increasing pressure, according to the Washburn equation, which describes the intrusion mechanism. The method consists of forcing mercury into the pores of a sample under increasing pressure and measuring the volume of mercury that has penetrated the material. The total volume of mercury is divided between the interparticle volume and the intraparticle volume (the pore volume). Porosity is expressed as the volume fraction of the pore volume relative to the total sample volume.

[0052] Preferably, the porous, silica-rich material has an open porosity greater than 60% and, particularly preferably, greater than 80%, or even greater than 90%.

[0053] Aggregates include both natural aggregates (e.g. gravel or sand) and recycled aggregates (e.g. crushed concrete or mortar).

[0054] Now it is possible to mix different types of aggregates, natural and recycled, in varying proportions.

[0055] As for particle size, a particle size between 4 and 10 mm is preferred, and a particle size between 4 and 6 mm is particularly preferred.

[0056] As with soil, it is possible to use aggregates from all or part of the site on which the process is implemented.

[0057] In the case where the soil used incorporates aggregates, then the proportion of aggregates added in addition to the soil is adapted so that the total volumetric proportion of aggregates is between 0 and 20%, preferably between 5 and 20% and particularly preferably between 10 and 20%.

[0058] According to yet another preferred embodiment, the process according to the invention will preferably include a step prior to step i) of extracting aggregates and, optionally, sieving them.

[0059] By crystallizer, sometimes also called mineralizer, we mean compounds capable of forming, through a reaction called mineralization, crystalline and insoluble complexes with the soluble compounds of the mortar (free lime).

[0060] Examples of such compounds include silicate salts, carbonate salts (e.g., natron), and alginate salts.

[0061] According to a particular embodiment, the crystallizer comprises at least one strong base in proportion such that the pH of the mixture at the end of step i) is equal to or greater than 9.0, preferably greater than or equal to 10.0 and, particularly preferably greater than or equal to 11.0. As a base, sodium or calcium hydroxide may be mentioned.

[0062] Such crystallizers are known for use in the waterproofing of concrete, notably under the names PENETRON, XYPEX, VANDEX, mineralizing B HYDRO-MINERAL, etc.

[0063] Preferably, the crystallizer includes silicate ions capable of forming silicate complexes with calcium hydroxide, including calcium, magnesium, sodium or potassium silicate.

[0064] Preferably, calcium and / or magnesium silicate should be used.

[0065] Depending on the silicate salt, it may or may not be possible to add a strong base.

[0066] Thus, if the use of sodium silicate does not imply the use of a complementary base, sodium or calcium hydroxide can be added in the case of a crystallizer comprising calcium and / or magnesium silicate.

[0067] According to a preferred embodiment of the process according to the invention, step if) is carried out simultaneously or consecutively with step ib), preferably simultaneously.

[0068] By fibers, we mean both synthetic fibers (e.g. polypropylene fibers, glass fibers, carbon fibers, etc.) and natural fibers (e.g. hemp), which fibers can be in any shape (elongated or circular), preferably in elongated form.

[0069] Advantageously, the fibers used are solid fibers, meaning they have a structure devoid of cavities.

[0070] Typically, the fibers used have a length of between 5 and 100 mm, preferably between 5 and 70 mm and, particularly preferred, between 10 and 50 mm.

[0071] Depending on the preferred embodiment, natural or plant fibers will be used. To obtain such plant fibers, fiber plants may be used, many of which are well known.

[0072] For bast fibers, corresponding to bark fibers, examples include hemp, jute, kenaf, barrel liana, flax, nettle, papyrus, esparto grass, linden fibers, bamboo fibers, Provence cane fibers, sea rush, miscanthus fibers, bagasse, etc.

[0073] Examples of leaf fibers include Manila hemp (from abaca), piña (from pineapple), and agave leaf fiber (e.g., sisal).

[0074] Examples of fibers derived from seeds or fruit include coir, rice hulls or straw, and cotton.

[0075] Finally, the mortar may incorporate other additives such as plasticizers, water-retaining agents, water-repellents, biocides, fungicides, dispersants, air-entraining agents (chasers), setting accelerators, setting retarders, fluidizers, antifreeze agents or expanding agents.

[0076] Naturally, each of these additives can be added to the mortar alone or in combination with one or more other additives.

[0077] Step i) of mixing can be carried out according to techniques well known to a person skilled in the art.

[0078] Advantageously, the mixing is carried out using a mixer, in particular a mobile mixer with horizontal or vertical axes allowing the mixing to be carried out on the very site where the wall is to be built.

[0079] If the earth-based mortar cannot be used immediately after step i), it is also possible, omitting to add at least water, to bag the mixture during step i) for transport and / or storage before finalizing it prior to its use in step ii) of the process according to the invention.

[0080] Step ii) of pumping can be carried out according to techniques well known to those skilled in the art.

[0081] This pumping step is carried out using a pumping device such as a piston pump or a screw pump.

[0082] Advantageously, the mixture is heated to a temperature greater than or equal to 40°C, preferably greater than or equal to 45°C during this pumping stage so as to allow rapid setting of the mortar, especially in the case of projection onto a vertical surface.

[0083] Such a temperature may possibly be obtained by the mere friction of the mixture obtained at the end of step i) with the surfaces of the device enabling the pumping (e.g. friction of the mixture with the surface of the screw).

[0084] According to another particular embodiment of the process according to the invention, it is intended for projection onto a horizontal or vertical surface, preferably onto a vertical surface.

[0085] Indeed, and surprisingly, the characteristics of the earth-based mortar according to the invention, and in particular its rapid setting time, allow it to be applied to a vertical surface in layers of approximately ten centimeters without any sagging. Furthermore, it is possible to apply successive layers of the mortar according to the invention with a recoating time of between 30 minutes and 6 hours between successive layers, preferably between 1 and 3 hours.

[0086] Advantageously, the process according to the invention allows for the creation of an earth-based mortar thickness of up to 50 cm, preferably up to 25 cm. It should be noted that this thickness can be achieved by means of one or more applications of the mortar to the surface. Typically, each application will increase the thickness by a maximum of 10 cm.

[0087] Now and preferably, the surface onto which the earth-based mortar is projected includes a reinforcing element, which can for example take the form of a reinforcement, which reinforcement can be metallic, plastic (polyethylene, polypropylene, etc.) or plant-based (bamboo, Provence cane, etc.).

[0088] Other features, details and advantages of the invention will become clearer from the detailed description given below by way of example. Preparing the spray machine:

[0089] The projection machine is adapted as follows: 1 / Replace the standard single-layer spray jacket (2L6) with a liquid screed jacket (60 / 12 or T 25) of varying lengths depending on the desired spray rate (jacket reference: 2L7 or equivalent). 2 / Install a 50 mm diameter hose for the initial lengths and reduce it to 35 mm for the last 10 meters if the line is longer than 10 meters. Otherwise, install a 50 / 35 reducer at the machine cone outlet with a 35 mm line. 3 / Install an air line connected to the machine's compressor with a T-fitting and two valves to control and adjust the airflow to regulate the mortar spray. 4 / Install a spray lance body with a 35 mm internal diameter and a nozzle with a diameter of 16 to 22 mm, depending on the spray pattern. Earth mortar preparation method

[0090] The soil from the site is sieved with 10 mm mesh.

[0091] The sieved site soil is then incorporated into the mixing tank of a TURBOSOL T20X spraying machine. Next, 4 / 6 gravel and 10 mm hemp fibers are added, and the mixture is rapidly mixed for a few minutes (generally about 2 minutes). Water is then added, and further rapid mixing ensures homogenization. Finally, the binder and crystallizer are added, and a longer mixing step (typically between 3 and 5 minutes) is carried out to achieve a smooth mortar consistency.

[0092] The mixture is then ready to be sprayed (or injected in the case of preparing building materials) Examples of formulations

[0093] Various earth mortar formulations were prepared, leading to the formula according to the invention. The tested earths included gypsum, quarry waste (limestone), silts, and clays.

[0094] Some of the formulas tested are described in tables 1 to 4. [Table1] MATTER VOLUME (litres) DENSITY WEIGHT (kg) % VOLUME (approximately) % MASS (approximately) LIME 5 0,791 3, 96 4% 3% DIATOMACEOUS EARTH 10 0,5 5 8% 4% MILKMAN 30 1,165 34,95 24% 27% EARTH 30 1,545 46,35 24% 35% 4 / 6 RECYCLED GRAVEL 15 1,26 18,90 12% 14% NATURAL FIBER 15 0,156 2,34 12% 2% CRYSTALLIZER 2 1,114 2,23 2% 2% WATER 18 1 18 14% 14% [Table 2] MATTER VOLUME (litres) DENSITY WEIGHT (kg) % VOLUME (approximately) % MASS (approximately) LIME 7,5 0,791 5,93 6% 5% DIATOMACEOUS EARTH 7,5 0,5 3,75 6% 3% MILKMAN 28 1,165 32,62 23% 25% EARTH 30 1,545 46,35 24% 35% 4 / 6 RECYCLED GRAVEL 15 1,26 18,90 12% 14% NATURAL FIBER 15 0,156 2,34 12% 2% CRYSTALLIZER 2 1,114 2,23 2% 2% WATER 18 1 18 15% 14% [Table 3] MATTER VOLUME (litres) DENSITY WEIGHT (kg) % VOLUME (approximately) % MASS (approximately) LIME 5 0,791 3, 96 4% 3% DIATOMACEOUS EARTH 11 0,5 5, 5 9% 4% MILKMAN 31 1,165 36,11 25% 28% EARTH 30 1,545 46,35 24% 35% 4 / 6 RECYCLED GRAVEL 15 1,26 18,90 12% 14% NATURAL FIBER 15 0,156 2,34 12% 2% WATER 18 1 18 14% 14% [Table3] MATTER VOLUME (litres) DENSITY WEIGHT (kg) % VOLUME % MASS LIME 25 0,791 19,78 22% 16,84% MILKMAN 25 1,165 29,13 22% 24,80% EARTH 25 1,545 38,63 22% 32,89% 4 / 6 RECYCLED GRAVEL 12,5 1,26 15,75 11% 13,41% NATURAL FIBER 12,5 0,156 1,95 11% 1,66% CRYSTALLIZER 2 1,114 2,23 2% 1,90% [Table 4] MATTER VOLUME (litres) DENSITY WEIGHT (kg) % VOLUME % MASS LIME 14 0,791 11,07 13% 9,31% MILKMAN 28 1,165 32,62 25% 27,41 % EARTH 28 1,545 43,26 25% 36,35% 4 / 6 RECYCLED GRAVEL 14 1,26 17,64 13% 14,82% NATURAL FIBER 14 0,156 2,18 13% 1,84% CRYSTALLIZER 2 1,114 2,23 2% 1,87% [Table 5] MATTER VOLUME (litres) DENSITY WEIGHT (kg) % VOLUME % MASS LIME 10 0,791 7,91 9% 6,75% MILKMAN 30 1,165 34,95 27% 29,83% EARTH 30 1,545 46,35 27% 39,56% 4 / 6 RECYCLED GRAVEL 10 1,26 12,60 9% 10,75% NATURAL FIBER 20 0,156 3,12 18% 2,66% CRYSTALLIZER 2 1,114 2,23 2% 1,90% [Table 6] MATTER VOLUME (litres) DENSITY WEIGHT (kg) % VOLUME % MASS LIME 5 0,791 3,96 5% 3,37% MILKMAN 15 1,165 17,48 14% 14,88% EARTH 40 1,545 61,80 37% 52,61 % 4 / 6 RECYCLED GRAVEL 15 1,26 18,90 14% 16,09% NATURAL FIBER 20 0,156 3,12 19% 2,66% CRYSTALISATOR 2 1,114 2,23 2% 1,90% Earth mortar projection stage

[0095] The earth mortar is then projected onto a previously prepared surface.

[0096] In the tests carried out, wooden frames were made, which frames had a base of OSB plywood panel screwed to the wooden structure and a welded wire mesh type metal grid positioned in the middle of the frame to allow the incorporation of elements traditionally used in the building trades (electrical wiring, water supply, etc.).

[0097] The application of the various earth mortars described above was then carried out in two successive layers of 7 to 8 cm. The re-coating time between the two layers was 30 minutes.

[0098] This timeframe can be considered short because, in reality, the panels produced on a typical construction site are larger. This will systematically result in a longer curing time (approximately 1 to 2 hours).

[0099] In the end, the infill panels produced in the workshop had a final thickness of 15 cm. After spraying, the mortar adhered perfectly and a finish was applied (straightening, troweling or smoothing depending on the panels). Properties of earth mortar

[0100] Test specimens of earth mortar were made in order to test its properties.

[0101] The tests carried out are as follows: Test on hardened concrete according to standard NF P18-459. Thermal conductivity test by the metric flux method according to standard NF EN 12667.

[0102] Hygrometric performance test by determining hygroscopic sorption properties (sorption and desorption curve) according to standard NF EN ISO 12571.

[0103] Air permeability and water tightness test.

[0104] Compression tests according to standard NF EN 12390-3 (by comparison with control elements).

[0105] Determination of dimensional variations due to moisture in aggregate concrete masonry elements according to standard NF EN 772-14. For each configuration.

[0106] Accelerated freeze / thaw aging tests according to standard NF EN 771-1 +A1 / CN.

Claims

1. A method for spraying an earth-based mortar using a spraying machine, which method comprises the steps of: i) preparing the earth-based mortar by mixing: ia) a soil from earthmoving or excavation operations, or crushed demolition materials, excluding topsoil, with a particle size of 20 mm or less, in a volume proportion of 20 to 55%; ib) a binder comprising slag or metakaolin and, optionally, lime, in a volume proportion of 15 to 55% ; ic) a material having a silica content greater than 50% by weight, an open porosity greater than 45% as measured by mercury intrusion porosimetry, a particle size of 5 mm or less, preferably 2 mm, and a volume fraction of 0 to 25%, or even 2 to 25%, preferably 3 to 20%, and particularly preferably 4 to 18%, for example 4 to 10% ; id) aggregates with a particle size between 2 and 20 mm, and a volume fraction of 0 to 20%; ie) fibers in a volume fraction of 0 to 30%; if) crystallizer in a volume fraction of 0 to 15%, or even 0.1 to 15%; and ig) water in a volumetric proportion of between 5 and 20%; ii) discharge of the mixture, at the end of step (i), into a loading hopper which is fixed to the frame of the spraying machine; iii) pumping of the mixture through an opening in this same loading hopper, using a progressive cavity pump, and injection of this mixture into a pipe extending from said pump; and iv) projection of the mixture, at the end of the pipe, onto a surface, preferably a vertical surface, by means of a lance terminating in a nozzle; where: - the progressive cavity pump does not have a jacket for spraying a one-layer rendering but a jacket for liquid screed or conventional mortar; - the pipe, if less than 10 meters long, has an internal diameter of approximately 35 mm, or, if longer than 10 meters, an internal diameter of approximately 50 mm at the outlet of the progressive cavity pump and an internal diameter of approximately 35 mm over its last 10 meters; - a projection lance body with an internal diameter of approximately 35 mm and a nozzle with a diameter between 16 and 22 mm; and - a compressed-air line opening at the end of the nozzle to allow the projection of the earth-based mortar onto the surface.

2. The method according to claim 1, characterized in that the step i) of mixing is carried out in a mixing container of the spraying machine, which mixing container is capable of pivoting around a horizontal tilting axis around the frame so as to allow the mixture to be emptied into the loading hopper.

3. The method according to claim 1, characterized in that it allows the projection of up to 14 m3 of earth-based mortar per day.

4. The method according to any one of claims 1 to 3, characterized in that the step iii) of pumping the mixture through an orifice of the same loading hopper, using a progressive cavity pump and injecting this mixture into a pipe extending from said pump, is carried out at a pressure between 8 and 18 bars.

5. The method according to claim 4, characterized in that step iii) of pumping the mixture through an orifice of the same loading hopper, by a progressive cavity pump and injection of this mixture into a pipe extending said pump is carried out at a pressure between 10 and 12 bars.

6. A spraying machine comprising a loading hopper fixed to its frame, a progressive cavity pump connected to an opening in this same hopper, which allows the pumping and injection of the mixture into a pipe extending from said pump; and at the end of the pipe, a lance terminating in a nozzle, where: - the progressive cavity pump does not have a jacket for spraying a one-layer rendering but a jacket for liquid screed or conventional mortar; - a compressed-air line terminates at the nozzle end to allow the projection of earth-based mortar onto the surface, and characterized in that the projection machine is capable of implementing the process as defined in any one of claims 1 to 5 and in that : - the pipe, if less than 10 meters long, has an internal diameter of approximately 35 mm or, if more than 10 meters long, an internal diameter of approximately 50 mm at the outlet of the progressive cavity pump and an internal diameter of approximately 35 mm over its last 10 meters, and further comprising : - a projection lance body with an internal diameter of approximately 35 mm and a nozzle with a diameter between 16 and 22 mm.

7. A kit for a spraying machine comprising: - a jacket for liquid screed or conventional mortar; - a compressed-air line opening at the end of the nozzle to allow the projection of the earth-based mortar onto the surface, characterized in that the kit is for a spraying machine capable of implementing the process as defined in any one of claims 1 to 5 and in that it further comprises: - a pipe, if less than 10 meters long, having an internal diameter of approximately 35 mm or, if more than 10 meters long, an internal diameter of approximately 50 mm at the outlet of the pump and an internal diameter of approximately 35 mm over its last 10 meters, and - a spraying lance body with an internal diameter of approximately 35 mm and a nozzle having a diameter between 16 and 22 mm.