Method for producing compacted earth tiles for decorative floor and wall cladding and compacted earth tiles obtained
Patent Information
- Application Number
- PCT/ES2026/070160
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2025-03-28
- Filing Date
- 2026-03-30
- Publication Date
- 2026-10-01
Smart Images
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Abstract
Description
[0001] DESCRIPTION
[0002] METHOD FOR MANUFACTURING COMPACTED EARTH TILES FOR DECORATIVE FLOOR AND WALL COVERINGS, AND COMPACTED EARTH TILES OBTAINED
[0003] This application claims priority over Spanish patent application P202530260 filed on March 28, 2025.
[0004] The present invention relates to a method of manufacturing compacted earth-based tiles for high energy efficiency pavements and coverings, the method of which has a reduced or practically zero environmental impact, in terms of CO2 emissions, with scalable process stages for mass production.
[0005] Background of the invention
[0006] The use of earth as a building material dates back thousands of years, making it one of the oldest and most sustainable techniques used by humankind. From ancient civilizations to traditional constructions in various cultures, rammed earth has proven to be a durable, energy-efficient material capable of naturally regulating humidity and interior temperature.
[0007] Rammed earth construction, also known as rammed earth or compacted earth, involves compacting damp soil. The mixture is compacted into a solid, and once dry, the formwork is removed to reveal monolithic walls and continuous pavements. Rammed earth constructions, also known as rammed earth buildings, can be found in various countries. The availability of suitable soil and a construction design adapted to local climatic conditions are two factors that favor its use for walls and floors.
[0008] The compressive strength of rammed earth depends, among other factors, on the amount of binder used. Thus, the greater the amount of binder, the greater the compressive strength. However, adding more binder can affect the hygroscopicity of the walls. In fact, properly constructed rammed earth can last for thousands of years, as demonstrated by many ancient structures still preserved around the world. In some structures, these rammed earth walls have been reinforced with fibers. A significant advantage of rammed earth is its high thermal mass: like concrete, it absorbs heat during the day and releases it at night, or vice versa. This action moderates temperature variations and reduces the need for air conditioning and heating. Depending on the type and content of the binder, it must also be protected from moisture.
[0009] The mass of the material and the clay content of rammed earth allow the walls of a building to breathe better than concrete buildings.
[0010] Rammed earth walls and floors have the color and texture of natural soil. The thickness can be as little as 150 mm (15 cm) for non-load-bearing walls and up to 600 mm (60 cm) or more for load-bearing walls.
[0011] Currently, compressed earth blocks (CEBs) have been developed as environmentally sustainable building blocks, with industrialized manufacturing processes. CEBs are made from a mixture of soil, sand, clay, and often a consolidant (binder), which is compacted using a mechanical press. These CEBs typically have a rustic finish and very limited design options. Although this construction system offers strength, durability, and energy efficiency, these blocks are primarily used for building walls and partitions.
[0012] Although compressed or compacted earth technology has been used in soils as continuous pavement, the method is complex to implement. Furthermore, these continuous earth pavements typically have a thickness of 100 mm (10 cm) or more.
[0013] Hydraulic or terrazzo tiles are also available, traditional and aesthetically valued options. However, these tiles lack hygroscopic properties, meaning they don't help regulate ambient humidity. Furthermore, their manufacturing process has an environmental impact that could be improved.
[0014] On the other hand, there are terracotta tiles, whose composition includes a mixture of earth and clay. The material used is the same as for roof tiles or bricks. Furthermore, these tiles are made with fired clay, and the method involves firing at high temperatures. Therefore, neither the manufacturing method nor the resulting tiles can be considered sufficiently environmentally sustainable in terms of CO2 emissions.
[0015] Therefore, there is still an opportunity to provide a method for manufacturing rammed earth tiles that is environmentally sustainable in terms of greenhouse gas emissions such as CO2 and that can produce tiles of varying thicknesses and / or small formats, suitable for paving floors or cladding walls of different perimeters and sizes, with the appropriate strength for flooring. Furthermore, it is even more desirable to provide a manufacturing method for rammed earth tiles that retains the many advantages of rammed earth, facilitates industrialization, and allows for elegant and sophisticated (less rustic) finishes.
[0016] Therefore, with the growing popularity of environmentally friendly products that use sustainable materials, and the need to reduce the emission of greenhouse gases such as CO2, the need to provide a method for manufacturing compacted earth-based tiles that is easily scalable for industrialized production is clear.
[0017] Description of the invention
[0018] The objective of the present invention is to provide, in the first aspect, a method for manufacturing compacted earth tiles that solves the problems of the prior art cited and presents the advantages described below.
[0019] In accordance with this objective, the present invention provides a method for manufacturing compacted earth tiles for decorative floor and wall coverings, characterized in that the tile includes, as dry raw material, earth and a binder consisting of cement and / or lime, and the method is exempt from firing and comprises the following steps:
[0020] - a first stage of sieving the dry raw material to a particle size equal to or less than 10 mm, wherein the dry raw material comprises binder and soil; - a second stage of dry mixing the sieved dry raw material to a binder / soil ratio between 1:2 and 1:10 to obtain a dry mix;
[0021] - a third stage of mixing the dry mix in water by progressively adding water, preferably at a water / binder ratio of up to 1 / 15, to obtain a semi-dry mix.
[0022] - a fourth stage of pouring the semi-dry mixture into a tile mold and then pressing the mixture mass into the mold under pressure, followed by demolding the tile to obtain a tile in a semi-dry state; and
[0023] a final tile drying stage outside the chamber
[0024] Where the binder is cement or a mixture of cement and lime, after the fourth stage, the method further comprises a fifth stage of chamber curing of the tile for a period of at least 7 days, in an environment with a relative humidity above 70% and a controlled temperature between 19°C and 22°C, after which period the tile is removed from the chamber and the final stage is continued, and where the binder is lime, after the fourth stage, the method continues with the final stage.
[0025] It is worth noting that the method of manufacturing compacted earth tiles according to the present invention does not include a baking stage.
[0026] It is also particularly noteworthy that the method of manufacturing compacted earth tiles according to the present invention is capable of obtaining a tile with a smooth, fine, elegant finish, very different from existing BTS.
[0027] In one option, the compacted earth tile is single-layer. In this embodiment, the surface roughness of the tile's visible face will depend primarily on the particle size used during the sieving stage in the first phase and / or the amount of water used in the resulting mixture in the third phase. Smaller particle sizes result in lower surface roughness, while a higher water content results in lower surface roughness.
[0028] In another option, the compacted earth tile is two-layered. In this embodiment, the method described above repeats the cycle from stages one to four, up to the pouring into the mold, in which in the second cycle at least one of the following stage conditions is met: - in the first stage, the sieving particle size is smaller than that used in the particle size of the first cycle;
[0029] - In the third stage, the water / binder ratio is greater than the water / binder ratio used in the first cycle, i.e., the semi-dry mixture includes a greater amount of water than that of the first cycle;
[0030] And, in the fourth stage, the semi-dry mixture obtained in the second cycle is poured over the semi-dry mixture previously poured into the tile mold during the first cycle, and then the pressure mold is pressed, the two-layer tile is demolded and the remaining stages of the method are continued.
[0031] Surprisingly, the method of manufacturing compacted earth tiles according to the first aspect of the present invention is capable of obtaining compacted earth tiles with different degrees of surface finish on the visible face of the tile and is therefore also a versatile manufacturing method with regard to surface finish.
[0032] Advantageously, the compacted earth tile according to the present invention is of any format, preferably with sides equal to or less than 250 mm, which provides ease of installation in small spaces and / or perimeters with complex shapes.
[0033] In a preferred embodiment, the tile has a thickness of 35 mm, even more preferably between 25 and 15 mm, even more preferably between 20 and 15 mm.
[0034] Unlike other compacted earth products, the manufacturing method according to the present invention is capable of providing a wide range of tile formats with the appropriate thickness for use in decorative floor coverings and architectural applications.
[0035] Furthermore, rammed earth tiles can be customized in terms of color, texture, and surface design, giving architects and designers much more creative freedom and adaptability with unique and personalized finishes than can be achieved with in-situ walls or pavements or with BTC.
[0036] As described above, the manufacturing method yields single-layer, unfired, thin compacted earth tiles or double-layer, unfired, thin compacted earth tiles with a finer surface finish. Advantageously, the resulting tile retains the inherent benefits of compacted earth construction while also adding versatility in design, surface finish, and industrialization.
[0037] Advantageously, the manufacturing method and the compacted earth tiles defined in the present invention also contribute to the development of new forms of sustainable construction and to the improvement of the energy efficiency of the spaces provided with them.
[0038] Compared to prior art tiles, tiles according to the invention are manufactured without firing, which significantly reduces CO2 emissions. Furthermore, they can be manufactured using local materials or materials found naturally in nature, minimizing the carbon footprint associated with the transportation and processing of raw materials (examples). Additionally, their thermal regulation capacity helps maintain a more stable indoor temperature in homes, reducing the need for artificial heating and cooling and improving the building's energy efficiency. These advantages are achieved through a sustainable manufacturing approach that optimizes the use of natural resources and eliminates energy-intensive processes such as firing or the use of chemical additives.
[0039] In a preferred embodiment, the manufacturing method is free of chemical additives. Advantageously, the use of rammed earth tiles according to the second aspect of the invention further improves indoor air quality through natural humidity regulation. Rammed earth tiles are composed of natural materials with hygroscopic properties, allowing them to absorb and release moisture naturally according to ambient conditions. This self-regulating capacity helps maintain an optimal humidity level in indoor spaces, preventing excessively dry or humid environments.
[0040] Advantageously, its self-regulating humidity capacity reduces the proliferation of mites and mold, significantly improving air quality and environmental comfort. This advantage stems from the porous and natural composition of compacted earth, which facilitates the exchange of water vapor without the need for chemical treatments or synthetic additives.
[0041] The invention is then described in more detail, with reference to different embodiments that can be combined where technically possible. First and second stages: Dry raw material
[0042] In a preferred embodiment, the method for obtaining compacted earth flooring tiles begins with sieving the dry raw material to a particle size equal to or less than 10 mm, 9 mm, 8 mm, 7 mm, 6 mm, 5 mm, 4 mm, 3 mm, 2 mm, or 1 mm. It is common knowledge among those skilled in the art that smaller particle sizes, with appropriate particle size distribution, result in a smoother surface finish on the visible face of the tile.
[0043] In a preferred embodiment, the binder comprises cement. In this embodiment, the tile manufacturing method includes a fifth step, in which the tile is cured in a chamber for a period of at least 7 days, after which the tile is removed from the chamber. The chamber curing provides a high degree of ambient humidity, preferably above 70%, more preferably above 80%, and even more preferably above 90%. Furthermore, the chamber curing allows for temperature control within the chamber. In a preferred embodiment, the temperature in the chamber is between 19°C and 22°C, more preferably approximately 20°C.
[0044] The inventors of the present invention theorize that fluctuations in relative humidity significantly influence the final properties of tiles containing cement as a binder. Therefore, this chamber curing stage is essential in the manufacturing process for rammed earth tiles when the binder comprises cement.
[0045] The cement can be of any type available in the state of the art.
[0046] In a preferred embodiment, the cement is Portland cement.
[0047] The cement-to-soil ratio is between 1:2 and 1:10. Therefore, the method defined in the appended claims covers a ratio of 1:2 to 1:4, or a ratio of 1:4 to 1:10, or any intermediate ratio. Lower or higher ratios than those mentioned could also be used, depending on the type of soil used.
[0048] In another preferred embodiment, the binder consists of lime. In this embodiment, the tile manufacturing method does not require carrying out the optional fifth step, so that after the fourth step, in which the semi-dry mixture is poured into the tile mold, pressed into the mold, and demolded in a semi-dry state, the method continues with the sixth step, in which the tile is air-dried (without a chamber) for a period of at least 20 days.
[0049] Lime can be hydraulic lime, which contains impurities that react with water, allowing it to harden even in humid environments.
[0050] In this embodiment, the lime / soil ratio is between 1:2 and 1:10. Therefore, the method defined in the appended claims covers a lime / soil ratio of 1:2 to 1:4, or a lime / soil ratio of 1:4 to 1:10, or any intermediate ratio.
[0051] In another embodiment, the binder is a mixture of cement and lime.
[0052] In this embodiment, the cement / lime ratio can be between 1:2 and 1:10, the cement and lime mixture being the total amount of binder in the mixture with the earth and in the mixture with water according to the ratios described in the manufacturing method in this description.
[0053] When the binder is a mixture of cement and lime, the manufacturing method comprises the fifth stage of chamber curing, as described in the embodiment where the binder comprises cement.
[0054] In a preferred embodiment, the method of manufacturing compacted earth tiles further comprises aggregates and / or fiber as dry raw material.
[0055] The aggregate and / or fiber are mixed with the soil in an optional stage between the first and second stages to increase the soil's aggregate and / or fiber content. Therefore, in the remaining stages of the method, the term "soil" includes the aggregate and / or fiber previously mixed with the soil in that optional stage.
[0056] Aggregates such as gravel may be mixed with the soil in a percentage by weight of less than 40% with respect to the weight of the soil, preferably equal to or less than 30% with respect to the weight of the soil.
[0057] Preferably, the gravel particle size is between 1 mm and 10 mm. The higher the concentration of aggregates, the lower the hygroscopicity and thermal inertia of the resulting tile.
[0058] The percentage of aggregate to mix with the soil depends on the soil type. For clay soils, which have a minimal content of siliceous or calcareous aggregates, the percentage of gravel to mix can range from 15% to 40% by weight of the soil. For siliceous or calcareous soils, which have a higher gravel content, the percentage of additional gravel to mix can range from 25% to 0% by weight of the soil.
[0059] The soil used to manufacture the compacted earth tiles can be of any type. Therefore, the method of the present invention covers, for example, the use of soil from excavations carried out for construction purposes. As is known, before building, it is necessary to remove the soil from the space that will be occupied by the foundations. Advantageously, the manufacture of compacted earth tiles includes the use of soil from excavations.
[0060] In the present invention, naturally available aggregates are preferred to provide an environmentally sustainable tile manufacturing method, although it also contemplates unfired aggregates from rubble to provide a tile manufacturing method with a lower carbon footprint.
[0061] The fiber can be fiberglass or straw and can be present in a percentage by weight of less than 10% with respect to the weight of the soil, preferably equal to or less than 5% with respect to the weight of the soil.
[0062] By way of example, the authors of the present invention have manufactured different types of compacted earth tiles depending on whether they include cement or lime and optionally aggregates such as gravel or fiber such as fiberglass or straw.
[0063] In yet another embodiment, combinable or not with any of the previous embodiments, the dry raw material also comprises an organic colorant of natural origin.
[0064] The colorant must be mixed in at the beginning of the method, being an additional component of the dry raw material to provide a colored tile.
[0065] Third stage: Semi-dry mix
[0066] At this stage, the water / binder ratio can be up to 1:15. The mixture is kneaded until a homogeneous semi-dry mixture is obtained.
[0067] In a preferred embodiment, water is added gradually to the dry mixture.
[0068] Fourth stage: Pouring into mold and pressing
[0069] At this stage, once the homogeneous semi-dry mixture is obtained, it is poured into tile molds. In a preferred embodiment, the molds are suitable for obtaining tiles of 200 x 200 mm, 250 x 250 mm, 300 x 300 mm, but also larger ones, for example, 1000 x 1000 mm or more.
[0070] In a preferred embodiment, once the tile mold is filled, the wet mix mass is pressed by applying pressure using any type of press suitable for this purpose, preferably a hydraulic press.
[0071] Fifth stage: Curing in chamber
[0072] In a preferred embodiment in which the binder includes cement, the method is carried out including the fifth stage of chamber curing.
[0073] After filling the tile molds with the mixture, applying pressure to compress and shape the mixture within the mold receptacle, and then removing the tiles from the mold, the resulting tiles are submerged in water and subsequently placed in the curing chamber. The chamber is an isolated space, so the curing of the tiles takes place in an environment with a relative humidity above 70%.
[0074] As described above, this step is essential when the binder includes cement, and therefore, this chamber curing step is also carried out when the binder is a mixture of cement and lime.
[0075] The curing process takes place inside the chamber for a period ideally no less than 7 days. Preferably, the curing is carried out over a period of 7 days, although it can be longer, for example, up to 10 days.
[0076] The use of a curing chamber does not imply controlling the relative humidity level inside the chamber, but rather preventing humidity fluctuations. Because the chamber is isolated from the outside, the water that evaporates from the tile is retained within it as ambient humidity, thus ensuring a high humidity level throughout the curing period. The inventors of this invention theorize that fluctuations in relative humidity significantly influence the final properties of the tiles. Therefore, this curing stage in the chamber is essential in the manufacturing method for cement-bonded, compacted earth tiles according to this invention.
[0077] Advantageously, during the investigation, the authors of the present invention have found that chamber curing prevents the formation of cracks or imperfections both inside and outside the tile when it includes cement, thus ensuring adequate strength of the compacted earth tile and a high-quality finish.
[0078] Sixth stage: Drying
[0079] In a preferred embodiment, drying is done in ambient air.
[0080] The method of manufacturing compacted earth tiles may comprise additional stages that can be combined with each other whenever technically possible.
[0081] Finishing stage, in which brushing, polishing, application of water repellent to the visible face of the tile, etc., can be carried out, providing a surface finish of the visible face of the tile with a different degree of roughness or surface texture.
[0082] The design stage involves applying a surface finish to the visible face of the tile, which can be stamped or printed using textured molds that mimic a specific texture. These molds imprint that texture onto the tile's surface and / or allow for the incorporation of different pigment or color mixtures, creating complex designs and patterns characteristic of mosaic tiles (for example, tiles with various colors forming geometric or floral figures).
[0083] The present invention solves the problems of the prior art in relation to the wear resistance of compacted earth applied to floor tiles, making them suitable for normal use.
[0084] It is common knowledge for someone knowledgeable in the field that a tile suitable for floors is equally suitable for walls.
[0085] In a second aspect, the present invention relates to a compacted earth tile for floors characterized by the fact that it has been obtained by the manufacturing method defined in the first aspect of the present invention.
[0086] In a preferred embodiment, the compacted earth floor tile is single-layer and unfired.
[0087] In a different embodiment, the compacted earth floor tile is two-layer and unfired. In a preferred embodiment, the compacted earth tile includes a binder consisting of cement.
[0088] In another preferred embodiment, the compacted earth tile includes a binder consisting of lime. The lime provides greater flexibility and breathability to the tile.
[0089] In yet another preferred embodiment, the compacted earth tile includes a binder consisting of a mixture of cement and lime.
[0090] In an embodiment that can be combined with any of the above embodiments, the thickness of the tile is equal to or less than 35 mm, even more preferably it has a thickness between 25 and 15 mm, even more preferably between 20 and 15 mm, for example, 18 mm.
[0091] For a better understanding of what has been explained, some drawings are included which, schematically and only as a non-limiting example, represent a practical case of implementation.
[0092] Brief description of the figures
[0093] Figure 1 shows a flow diagram schematically representing the method of manufacturing compacted earth tiles according to the present invention, wherein the binder comprises cement.
[0094] Figure 2 shows a flow diagram schematically representing the method of manufacturing compacted earth tiles according to the present invention, wherein the binder consists of lime.
[0095] Figure 3 is a photograph of a sample of compacted earth tiles with different colors and shades obtained according to the manufacturing method of the invention depicted in Figure 1 or Figure 2, without surface finish design. The lower part of Figure 3 includes an enlarged detail showing the reduced thickness of the resulting tile.
[0096] Figure 4 is a photograph of a plan view of a compacted earth floor tile obtained according to the manufacturing method of the invention represented in Figure 1 or Figure 2, with a colored surface finish design on the visible face of the tile. For a better understanding of the invention, some non-limiting examples of the scope defined in the appended claims are included below.
[0097] Examples
[0098] Example 1: Example of a composition for the manufacture of compacted earth floor tiles, wherein the binder comprises cement
[0099] Tile composition for 30 kg of dry raw material:
[0100] Subsoil soil: 24 kg;
[0101] Binder: cement: 6 kg;
[0102] Cement:soil ratio 1:4;
[0103] Water: 2 kg (liters);
[0104] Water / cement ratio 2 / 6 = 0.33
[0105] Example 2: Example of manufacturing compacted earth floor tiles with the composition of example 1
[0106] This example is developed following the flowchart represented in Figure 1.
[0107] First, the soil is sieved using a sieve with particle size control set at 2 mm.
[0108] The soil and cement are mixed dry in a standard mixer for approximately 5 to 10 minutes. Water is gradually added to the mixer until a homogeneous, wet mix is obtained.
[0109] Next, the homogeneous wet mixture obtained is poured into tile molds measuring 200 x 200 mm and the mass is compacted using a hydraulic press, and a pressure of 50 bar.
[0110] Next, the tiles are removed from the molds, soaked in water, and placed in a chamber isolated from the outside, where they undergo curing. The tiles remain in the chamber for 7 days. After 7 days, the tiles are removed from the chamber and air-dried for another 28 days.
[0111] Example 3: Example of composition for the manufacture of compacted earth floor tiles, in which the binder consists of lime
[0112] Unlike Example 1, the composition in Example 3 substitutes lime for cement. Tile composition for 30 kg of dry raw material: Subsoil: 24 kg;
[0113] Binder: lime: 6 kg;
[0114] Caktierra dosage 1:4;
[0115] Water: 2.5 kg (liters);
[0116] Water / lime ratio 2.5:6 = 0.42
[0117] Example 4: Example of manufacturing compacted earth tiles for floors with the composition of example 3
[0118] This example is developed following the flowchart represented in Figure 2.
[0119] First, the soil is sieved using a sieve with particle size control set at 2 mm.
[0120] The soil is mixed with the lime in a standard mixer for approximately 5 to 10 minutes to obtain a dry mix. Water is then gradually added to the mixer until a homogeneous, wet mix is achieved.
[0121] Next, the homogeneous wet mixture is poured into tile molds measuring 200 x 200 mm and the mass is compacted using a hydraulic press and a pressure of 50 bar.
[0122] Next, the tiles are removed from the mold and placed in the open air for a period of 28 days.
[0123] Example 5: Example of a composition for the manufacture of compacted earth floor tiles, wherein the binder comprises cement
[0124] Unlike Example 1, the composition also includes aggregates at a concentration of 20% by weight with respect to the total weight of dry matter (soil, cement and gravel).
[0125] Tile composition for 30 kg of dry raw material:
[0126] Subsoil soil: 19 kg
[0127] Binder: cement: 5 kg
[0128] Aggregate: Gravel 4 mm: 6 kg (20% of the total)
[0129] Cement:soil ratio 1:4;
[0130] Water: 1.7 kg (liters);
[0131] Water / cement ratio 1.7:5 = 0.34 Example 6: Example of manufacturing compacted earth tiles for floors with the composition of example 5
[0132] This example is developed following the flowchart represented in Figure 1.
[0133] First, the sieving is carried out, on the one hand, of the soil using a sieve with particle size control set at 2 mm and, on the other hand, of the gravel, using the same sieve with particle size control set at 4 mm.
[0134] The soil is mixed with the gravel and then with the cement in a standard mixer for approximately 5 to 10 minutes to obtain a dry mix. Water is gradually added to the mixer until a homogeneous, wet mix is achieved.
[0135] Next, the homogeneous wet mixture obtained is poured into tile molds with sides of 200 x 200 mm and the mass is compacted using a hydraulic press and a pressure of 50 bar.
[0136] Next, the tiles are removed from the molds, soaked in water, and placed in the curing chamber. They remain in the chamber for 7 days. After 7 days, the tiles are removed from the chamber and the process continues with an outdoor drying stage that lasts for 28 days.
[0137] Essays
[0138] The following tests were carried out: Abrasion resistance and Flexural strength.
[0139] For the abrasion resistance test, the method described in the LINE-EN 13748-1:2024 standard was used, although the minimum values indicated by this standard are suitable for other types of material such as terrazzo.
[0140] Regarding the flexural strength test, there is no specific standard for compacted earth and again the method described in the same previous standard was used, which also includes flexural strength and breaking load, although the minimum requirements were determined from the results obtained in the tests and also tested in use.
[0141] Different samples of compacted earth tiles were prepared to be subjected to the three tests according to Table 1.
[0142]
[0143] (*) Type 1 indicates a land in Campos (Mallorca), Type 2 indicates a land in Manacor (Mallorca) and Type 3 indicates a land in Nador (Morocco)
[0144] From Table 1 it can be observed that the samples vary in the type of binder, binder:earth ratio, aggregate content and aggregate particle size provided in relation to the sieve used.
[0145] During the investigation, the inventors of the present invention determined the minimum average footprint length for the compacted earth tiles of the invention based on tests and real-world use. Thus, an average footprint length, measured in mm, of 31 or less is perfectly acceptable and suitable for use, as it exceeds the results obtained by terracotta tiles tested according to the same standard.
[0146] During the investigation, the authors of the present invention also determined the minimum flexural strength and the minimum breaking load for compacted earth tiles
[0147] Table 2 shows the results obtained in the tests with the prepared samples.
[0148]
[0149] Compacted earth tiles should not be subjected to bending in any of their applications.
Claims
CLAIMS 1. Method of manufacturing compacted earth tiles for decorative floor and wall coverings, characterized in that the tile includes, as dry raw material, earth and a binder consisting of cement and / or lime, and the method is exempt from firing and in that it comprises the following steps: - a first step of sieving the dry raw material to a particle size equal to or less than 10 mm, wherein the dry raw material comprises binder and earth; - a second stage of dry mixing of the sieved dry raw material to a binder:earth ratio between 1:2 and 1:10 to obtain a dry mix; - a third stage of mixing the dry mix in water by progressively adding water to obtain a homogeneous semi-dry mix, with a water / binder ratio of up to 1:15, - a fourth stage of pouring the semi-dry mix into a tile mold and then pressing the semi-dry mix mass into the mold, followed by demolding the tile to obtain a tile in a semi-dry state; and - a final drying stage of the tile outside the chamber, Where the binder is cement or a mixture of cement and lime, after the fourth stage, the method further comprises a fifth stage of chamber curing of the tile for a period of at least 7 days, in an environment with a relative humidity above 70% and a controlled temperature between 19°C and 22°C, after which period the tile is removed from the chamber and the final stage is continued, and where the binder is lime, after the fourth stage, the method continues with the final stage.
2. A method for manufacturing compacted earth tiles according to claim 1 to obtain a single-layer tile.
3. A method for manufacturing compacted earth tiles according to claim 1, wherein steps one through four, up to pouring into the mold, comprise a first cycle, and wherein the method further comprises repeating the first cycle in a second cycle, which meets at least one of the following step conditions: - In the first stage of the second cycle, the sieving particle size is smaller than the sieving particle size of the first cycle; - In the third stage of the second cycle, the water / binder ratio is greater than the water / binder ratio of the first cycle, so that the mixture in the second cycle includes a greater amount of water compared to that of the first cycle; and. because, in the fourth stage of the second cycle, the mixture obtained is poured over the semi-dry mixture of the first cycle in the tile mold and then pressed, followed by demolding the tile to obtain a two-layer tile in a semi-dry state and then proceeding with the remaining stages of the method.
4. Method of manufacturing compacted earth tiles according to any one of claims 1 to 3, wherein in the third stage the water / binder ratio is up to 1 / 15.
5. Method of manufacturing compacted earth tiles according to claim 1, wherein the binder is cement or a mixture of cement and lime, the method further comprises, between the fourth and fifth stages, immersing the tiles in water before entering the curing chamber.
6. Method of manufacturing compacted earth tiles according to any one of claims 1 to 5, wherein the dry raw material further includes aggregates, such as gravel, in a percentage by weight equal to or less than 40% of the total weight of the dry raw material, preferably equal to or less than 25% of the total weight of the dry raw material.
7. Method of manufacturing compacted earth tiles according to any one of claims 1 to 6, wherein the dry raw material further includes fiber selected from fiberglass or straw in a percentage by weight equal to or less than 10% of the total weight of the dry raw material, preferably equal to or less than 5% of the total weight of the dry raw material.
8. Method of manufacturing compacted earth tiles according to any one of claims 1 to 7, wherein the dry raw material further includes a colorant of natural origin.
9. Method of manufacturing compacted earth tiles according to any one of claims 1 to 8, wherein in the second dry mixing stage, the binder:earth ratio is approximately 1:
4.
10. Method of manufacturing compacted earth tiles according to any one of claims 1 to 9, wherein in the third stage of mixing in water, the water:binder ratio is approximately 1:
4.
11. Method of manufacturing compacted earth tiles according to any one of claims 1 to 10, wherein in the fourth stage the mold is a textured mold suitable for imprinting a texture on the visible surface of the tile.
12. Method of manufacturing compacted earth tiles according to any one of claims 1 to 11, wherein in the fourth stage the mold is provided with a colored design for coloring the visible surface of the tile.
13. Compacted earth tile for decorative floor and wall coverings characterized in that it has been obtained by the manufacturing method defined in any one of claims 1 to 12.
14. Compacted earth tile for floors according to claim 13, wherein the tile is of a thickness equal to or less than 30 mm, preferably equal to or less than 20 mm.
15. Compacted earth tile according to any one of claims 13 to 14, wherein the tile is square or rectangular and has a side length of less than 300 mm.
16. Compacted earth tile according to any one of claims 13 to 15, wherein the tile has a textured and / or colored design on the visible face.
17. Use of a compacted earth tile as defined in any one of claims 13 to 16 for decorative floor and wall coverings.