Dry mortar composition, in particular mortar adhesive for tile adhesive

Abstract

The invention relates to a dry mortar composition, in particular mortar adhesive for tile adhesive, comprising a mineral binder and at least one thermally expandable material.

Description

Description Title of the invention: Dry mortar composition, in particular adhesive mortar for tile adhesive

[0001] The present invention belongs to the field of mortars based on mineral binder.

[0002] By "mineral binder" we mean, where appropriate, collectively, a mixture of several mineral binders.

[0003] These mortars come in the form of a dry composition, ready to mix with water.

[0004] By "dry (mortar) composition" or "dry mortar" is meant a powdery mixture in which the mineral binder and any aggregates and / or additives are in the form of powders and grains. After mixing with water, or the so-called mixing stage, a paste, or wet mortar, is obtained, which can be applied to a substrate.

[0005] The invention relates more particularly to adhesive mortars for tile adhesives.

[0006] In this case, the wet mortar is placed on a substrate to ensure the tiles are fixed to it.

[0007] In particular, fixing is ensured by drying the wet mortar to form a dried mortar.

[0008] Once this fixation is ensured, however, there is currently no fully satisfactory solution for breaking it, for example to replace a tile. To this end, the options open to users are either to break the mortar, which turns out to be a laborious and difficult operation, or to cover an existing tile with, for example, new tiles, paint, resin or polished concrete.

[0009] Click-on tiles, applied without any adhesive, are commercially available. However, while easy to install, this type of tile remains expensive and requires a smooth floor. It is also not suitable for use on walls. According to users, it is also difficult to cut and repair, and is also less durable than conventional tiles.

[0010] Thus, there is a need for versatile building materials, and in particular mortars, that offer the possibility of changing decoration, facilitating the recycling of materials used and even reusing them, for example within the framework of a circular economy. These materials should also offer properties and use comparable to those expected of materials commonly used.

[0011] The present invention aims to meet these needs by proposing materials having easily implemented disassembly properties. In the case of mortars, these disassembly properties can be achieved by degradation of the adhesion properties of the mortar.

[0012] In the field of adhesives, it is known that adhesion can be degraded by different types of stimuli such as thermal (by heating or cooling), electrical, radiative, mechanical or enzymatic.

[0013] For application to mortars, however, it is necessary that the degradation is irreversible or at least lasts long enough to allow a user to remove the tiles.

[0014] The paper "Microwave dielectric heating to disassemble a modified cementitious joint" by J. Ahn published in Materials and structures, vol. 46, no. 12, pp. 2077-2090 in 2013 describes heating mortar to temperatures above 300 °C in order to degrade its adhesive properties. This technique has been used to degrade cement and recycle concrete aggregates, as described in the paper "Assessment of a microwave-assisted recycling process for the recovery of high-quality aggregates from concrete waste" by K. Bru et al. Published in International Journal of Mineral Processing, vol. 126, pp. 90-98, published in 2014.

[0015] However, this requires temperatures that are too high to be easily implemented by any user in the context of an application for dismantling tiles.

[0016] Patent application EP0994222 A1 describes a method for disassembling floor tiles on a mortar bed, carried out flat and requiring a high heating ramp. The disassembly here results from the expansion of the tiles under the effect of the temperature gradient between the tiles and the mortar. However, this method requires a specific device, which again complicates its implementation by a user.

[0017] The present invention aims to remedy all or part of the drawbacks of the prior art, in particular those set out above, by proposing a solution which makes it possible to degrade the adhesion properties of a mortar in order to achieve easy disassembly, for example, of a tile.

[0018] To this end, and according to a first aspect, the invention relates to a dry mortar composition, in particular adhesive mortar for tile adhesive, comprising a mineral binder and at least one thermally expandable material.

[0019] Such a composition according to the invention finds its interest, in particular, in the fact that it allows an expansion of the thermally expandable material, and therefore of the dry mortar under the effect of heating, said expansion leading to mechanical stress within the mortar, until it ruptures. Rupture under the effect of heating is therefore caused at lower temperatures than for mortars of the prior art.

[0020] Such thermally expandable materials are known, in particular in the form of thermally expandable particles, thermally expandable graphite or thermally expandable clays.

[0021] Thermally expandable particles have a thermoplastic shell containing hydrocarbons. When heated, the softening of the shell combined with the vaporization of the hydrocarbon core leads to an expansion of the particle volume.

[0022] Such particles are notably described in US patent 3,615,972 and are now made commercially available by the companies Expancel Nobel Industries and Mastumoto Yushi Seiyaku.

[0023] These particles, depending on the nature of their shell and core, can expand when heated above 80°C.

[0024] According to a preferred embodiment of the invention, the thermally expandable material is a thermally expandable graphite.

[0025] Thermally expandable graphite is known for its use as a flame retardant and is notably described in “Expandable graphite as an intumescent flame retardant in polyisocyanurate-polyurethane foams” by M. Modesti et al. in Polymer Degradation and Stability, vol. 77, no. 2, pp. 195-202 in 2002.

[0026] In thermally expandable graphite, molecules, usually containing sulfur, such as hydrogen sulfate ions or sulfuric acid, are intercalated between the graphite layers. Upon heating, the gaseous state of these molecules causes the graphite layers to expand accordion-like.

[0027] Various thermally expandable graphites are commercially available and can exhibit variable expansion in volume and temperature at which it is triggered. This temperature can be at least 110 °C.

[0028] A thermally expandable graphite suitable for the invention may be chosen from the GrafGuard range marketed by the company NeoGraf, the references EG-110-230 and EG-180-250 marketed by the company ACS Materials, 808121 by the company Sigma-Aldrich or Blahgraphit by the company AMG Graphite GK. Preferably, the thermally expandable graphite used in a composition according to the invention is the reference graphite Blahgraphit marketed by the company AMG Graphite GK.

[0029] Thermally expandable graphite may be present in a composition according to the invention in a content of from 0.3% to 10% by weight, in particular from 0.4% to 7% by weight and preferably from 0.5% to 5% by weight, relative to the total weight of the composition.

[0030] As demonstrated in the examples below, a low thermally expandable graphite content, i.e. less than 0.3% by weight, in particular less than 0.4% by weight and preferably less than 0.5% by weight relative to the total weight of a composition according to the invention, complicates the disassembly operation because it requires a longer heating time and a higher energy expenditure.

[0031] Likewise, a high thermally expandable graphite content, i.e. greater than 10% by weight, in particular greater than 7% by weight and preferably greater than 5% by weight relative to the total weight of a composition according to the invention, may compromise the adhesion properties of said composition.

[0032] The mineral binder in a composition according to the invention may be a hydraulic binder.

[0033] In particular, the hydraulic binder is chosen from Portland cements, in particular of type CEM I or CEM II, belitic cements, aluminous cements, sulfoaluminous cements, pozzolanic mixture cements, hydrated lime, slags, metakaolins, fly ash, sources of calcium sulfate and mixtures of two or more of these binders.

[0034] The term “Portland cement” refers to CEM I or CEM II cements, as defined in EN 197-1. A CEM I cement comprises at least 95% by weight of clinker, while a CEM II cement comprises at least 65% by weight of clinker and at most 35% by weight of at least one of the following compounds: blast furnace slag, silica fume, pozzolan, fly ash, calcined shale and limestone. A CEM II cement may be preferred due to its lower carbon footprint.

[0035] Slag is a by-product of an industrial process involving the melting of a starting material, a melting process intended to separate metals from an oxide phase, the latter being called "slag". The use of slag reduces the carbon footprint of the composition, and therefore of the process, compared to the use of cement.

[0036] The slag may be granulated, in the sense that it has undergone thermal quenching with water, resulting in grains that are generally predominantly amorphous. The granulated slag is then ground to make it more active. The slag in a composition according to the invention is therefore a ground granulated slag.

[0037] Preferably the slag is a ground granulated blast furnace slag. Such a slag, used as a binder, has the advantage of being insensitive to external sulphate attack.

[0038] Slag (especially ground granulated blast furnace slag) is preferably activated.

[0039] The binder then comprises, in addition to the slag, an activator. Activator is understood here to mean an activating compound (which improves the setting and / or hardening of the slag) or, collectively, a mixture of such compounds. The total proportion of activator in the binder is preferably from 1 to 20%, in particular from 2 to 15% by weight.

[0040] The activator is preferably chosen from the group formed by: bases (in particular alkali metal hydroxides, alkali metal silicates and alkali metal carbonates); phosphates, in particular salts derived from phosphoric acid such as alkali metal polyphosphates, in particular chosen from sodium, potassium and / or lithium, for example sodium tripolyphosphate; slag microparticles with a fineness greater than or equal to 6000 Blaine; microparticles of calcium and / or magnesium carbonate, calcium silicate hydrates or aluminum silicate hydrates; ground granulated aluminous slags; sources of calcium sulfate (in particular gypsum, hemihydrate or anhydrite); alkali metal sulfates, halides, nitrates or carboxylates; Portland cement; lime; and mixtures of at least two of these compounds.

[0041] According to a preferred embodiment, the activator comprises slag microparticles with a fineness greater than or equal to 6000 Blaine, in particular between 6000 and 15000 Blaine, in a content of from 1 to 35%, in particular from 5 to 15%, relative to the total weight of binder. The activator may further comprise at least one of the following compounds: a base, in particular chosen from hydroxides, carbonates and silicates of alkali and / or alkaline earth metals, in a total content of at most 1%, in particular between 0.2 and 0.4%, relative to the total weight of binder; a source of calcium sulfate; sulfates of alkali metals, in a total content of at most 1%, in particular between 0.2 and 0.4%, relative to the total weight of binder; Portland cement, aluminous cement or sulfoaluminous cement, in a total content of not more than 4% relative to the total weight of binder.

[0042] According to another preferred embodiment, the activator comprises microparticles of calcium and / or magnesium carbonate, calcium silicate hydrates or aluminum silicate hydrates, the BET (nitrogen) specific surface area of ​​which is greater than 1 m 2 / g and the average diameter is less than 5 pm. The activator may further comprise at least one of the following compounds: a base, in particular chosen from hydroxides, carbonates and silicates of alkali and / or alkaline earth metals, in a total content of at most 1%, in particular from 0.2 to 0.4%, relative to the total weight of binder; a source of calcium sulfate; sulfates of alkali metals, in a total content of at most 1%, in particular from 0.2 to 0.4%, relative to the weight of binder; calcium nitrate, calcium formate, Portland cement, a aluminous cement or a sulfoaluminous cement, in a total content of not more than 5% relative to the total weight of binder.

[0043] According to yet another preferred embodiment, the activator comprises a ground granulated aluminous slag, in particular the chemical composition of which comprises from 30 to 60% by weight of alumina, from 5 to 25% by weight of silica and from 20 to 40% by weight of lime, alumina being the most abundant constituent. The ground granulated aluminous slag is preferably obtained from the recycling by total melting of catalysts used for the desulfurization of petroleum products, in particular catalysts based on molybdenum and / or cobalt.The activator may further comprise at least one of the following compounds: a base, in particular chosen from hydroxides, carbonates and silicates of alkali and / or alkaline earth metals, in a total content of at most 2% relative to the total weight of binder; a source of calcium sulfate; sulfates of alkali metals, in a total content of at most 2% relative to the total weight of binder; Portland cement, an aluminous cement or a sulfoaluminous cement, in a total content of at most 2% relative to the total weight of binder.

[0044] In a particular embodiment of the invention, a dry mortar composition according to the invention comprises a Portland cement as mineral binder, in particular in a content of from 10% to 50% by weight and preferably of from 20% to 40% by weight relative to the total weight of the composition.

[0045] In another particular embodiment of the invention, the mineral binder is a binder comprising, in particular consisting of, Portland cement, aluminous cement and a source of calcium sulfate. This is then referred to as a ternary binder.

[0046] According to this embodiment, the source of calcium sulfate may be selected from gypsum, calcium sulfate hemihydrate, calcium sulfate anhydrite and mixtures thereof, and preferably the source of calcium sulfate is a mixture of calcium sulfate hemihydrate and calcium sulfate anhydrite.

[0047] In this embodiment, according to a first preferred alternative, the Portland cement may be present in a content of from 2% to 10% by weight, in particular from 3% to 9% by weight and preferably from 5% to 8% by weight relative to the total weight of the composition.

[0048] In this embodiment, according to the first preferred alternative, the aluminous cement may be present in a content of from 10% to 25% by weight, and preferably from 15% to 20% by weight relative to the total weight of the composition.

[0049] In this embodiment, according to the first preferred alternative, the source of calcium sulfate may be present in a content of from 2% to 10% by weight, in particular 4% to 9% by weight and preferably from 6% to 8.5% by weight, relative to the total weight of the composition.

[0050] In other words, according to the first preferred alternative, a composition according to the invention may comprise at least one of the following characteristics: a) the Portland cement is present in a content of from 2% to 10% by weight, in particular from 3% to 9% by weight and preferably from 5% to 8% by weight relative to the total weight of the composition, b) the aluminous cement is present in a content of from 10% to 25% by weight, and preferably from 15% to 20% by weight relative to the total weight of the composition, and / or c) the source of calcium sulfate may be present in a content of from 2% to 10% by weight, in particular from 4% to 9% by weight and preferably from 6% to 8.5% by weight, relative to the total weight of the composition.

[0051] In this embodiment, according to a second preferred alternative, the aluminous cement may be present in a content of from 30% to 60% by weight, and preferably of from 35% to 55% by weight, relative to the total weight of the composition.

[0052] In this embodiment, according to the second preferred alternative, the Portland cement may be present in a content of from 10% to 25% by weight, in particular from 11% to 23% by weight, and preferably from 12% to 20% by weight relative to the total weight of the composition.

[0053] In this embodiment, according to the second preferred alternative, the source of calcium sulfate may be present in a content of from 10% to 30% by weight, in particular from 11% to 27% by weight and preferably from 15% to 25% by weight, relative to the total weight of the composition.

[0054] In other words, according to the second preferred alternative, a composition according to the invention may comprise at least one of the following characteristics: a) the aluminous cement is present in a content of from 30% to 60% by weight, and preferably of from 35% to 55% by weight, relative to the total weight of the composition, b) the Portland cement is present in a content of from 10% to 25% by weight, in particular of from 11% to 23% by weight, and preferably of from 12% to 20% by weight relative to the total weight of the composition, and / or c) the source of calcium sulfate is present in a content of from 10% to 30% by weight, in particular from 11% to 27% by weight and preferably from 15% to 25% by weight, relative to the total weight of the composition.

[0055] In this embodiment, according to the second preferred alternative, a composition according to the invention may contain at most 0.1% by weight of aggregates, in particular it may contain less than 0.01% aggregates, relative to the total weight of the composition, and preferably, the composition according to the invention may be free of aggregates.

[0056] This second alternative is particularly interesting in terms of adhesion properties but also because it allows even faster disassembly while heating at a lower temperature as demonstrated in the examples below.

[0057] A composition according to the invention may also comprise fillers, fillers, sand and / or aggregates.

[0058] The fillers can be low density, mineral or organic lightening fillers such as expanded perlite, expanded vermiculite, expanded glass beads, hollow glass microspheres, cenospheres, expanded clays, expanded shale, pumice stones, expanded polystyrene.

[0059] The fillers are typically dolomitic, siliceous, calcareous and / or silico-calcareous and have a grain size of up to 150 pm.

[0060] Aggregates or sands with a grain size varying between 100 pm and 5 mm make it possible to influence the thickness, hardness, final appearance and permeability of the composition according to the invention.

[0061] A composition according to the invention may also comprise at least one accelerator and / or at least one retarder. The total content of the accelerator(s) and the retarder(s) is preferably from 0.001% to 1.0% by weight relative to the total weight of the composition. A composition according to the invention advantageously comprises both at least one accelerator and at least one retarder, so as to control both the setting and the hardening of the cement.

[0062] Accelerators suitable for the invention are, for example, alkali salts such as lithium or potassium sulfates and carbonates, or organic salts such as calcium formate.

[0063] The total content of accelerator(s) in a composition according to the invention is preferably from 0.001% to 0.1% by weight relative to the total weight of the composition.

[0064] Retarders suitable for the invention are, for example, carboxylic acids such as tartaric or citric acids, and their salts.

[0065] The total content of retarder(s) in a composition according to the invention is from 0.01% to 1.0% by weight relative to the total weight of the composition.

[0066] A composition according to the invention may further comprise at least one other additive chosen from rheological agents such as plasticizers and superplasticizers; biocidal protective agents; redispersible polymer powders; water-retaining agents; air-entraining agents; thickening agents; dispersing agents and pigments.

[0067] Thickening agents and water-retaining agents suitable for the invention are, for example, cellulose ethers and starch ethers. They may be included in a composition according to the invention in a content of from 0.05% to 0.10% by weight relative to the total weight of the composition.

[0068] The redispersible polymer powders suitable for the invention are, for example, polymer powders obtained from at least one monomer chosen from vinyl esters (in particular vinyl esters of carboxylic acids, branched or not, comprising from 1 to 15 carbon atoms), (meth)acrylates (in particular (meth)acrylates of alcohols comprising from 1 to 10 carbon atoms), (meth)acrylic acids, aromatic vinyls, alkenes such as ethylene or propylene, dienes and vinyl halides.

[0069] In particular, the redispersible polymer powders suitable for the invention are chosen from polymer powders obtained from at least two of the monomers mentioned above, preferably from powders of copolymers chosen from: vinyl acetate-ethylene copolymers, vinyl ester-ethylene-vinyl chloride copolymers, vinyl acetate copolymers, vinyl acetate-acrylate copolymers, copolymers of methyl methacrylate with n-butyl acrylate and / or 2-ethylhexyl acrylate, copolymers of methyl methacrylate with 1,3-butadiene, vinyl chloride-ethylene copolymers, vinyl chloride-acrylate copolymers, styrene-butadiene copolymers, styrene-acrylate copolymers, vinyl acetate-(meth)acrylic acid-ethylene terpolymers.

[0070] The content of redispersible polymer powders in a composition according to the invention is preferably from 0.2% to 2.0% by weight, relative to the total weight of the composition.

[0071] Thus, a composition according to the invention may comprise at least one additive chosen from retarders; accelerators such as calcium formate; rheological agents such as plasticizers and superplasticizers; biocidal protective agents; redispersible polymer powders such as polymer powders obtained from at least one monomer chosen from vinyl esters, (meth)acrylates, (meth)acrylic acids, aromatic vinyls, alkenes, dienes and vinyl halides; water-retaining agents; air-entraining agents; thickening agents such as cellulose ethers and starch ethers; dispersing agents and pigments, in particular the additive(s) is (are) present in a content of from 0.01% to 6% by weight and preferably from 0.1% to 4% by weight relative to the total weight of the composition.

[0072] The present invention also relates to construction materials, in particular adhesive mortars or tile adhesives, obtained by mixing a dry mortar composition according to the invention with water.

[0073] The adhesives thus obtained exhibit very satisfactory short-term curing (i.e. after 24 hours). The adhesive strength performance of the adhesives according to the present invention meets the specifications allowing them to be classified at least Cl, preferably C2, according to standard EN 12004:2007.

[0074] The present invention also relates, according to a second aspect, to a method of fixing a tile to a substrate comprising successively: a) mixing the dry composition according to the invention with water so as to obtain a wet mortar, b) applying the wet mortar to said substrate, and c) applying the tiles of said tile to said substrate.

[0075] In a particular embodiment of the fixing method according to the invention, a quantity of water of from 15% to 40% by weight, and preferably from 20% to 35% by weight, relative to the total weight of the wet mortar is introduced into the mixture of step a).

[0076] Finally, the present invention also relates to a method of disassembling a tile obtained according to a fixing method according to the invention, comprising a step of heating the mortar to a temperature of from 80°C to 300°C, in particular from 85°C to 250°C, and preferably from 90°C to 225°C, said heating step being carried out in particular by means of a heat gun, microwaves or by induction. Examples

[0077] Tile adhesive formulations comprising a mineral binder and a thermally expandable material were prepared by mixing the different constituents according to Table 1 below, which details the compounds constituting the different compositions used, in percentage by weight according to the total weight of the dry composition, and concerning the quantity of water added, as a percentage by weight relative to the total weight of the final composition. [Table 1]

[0078] The dry compositions of the above examples are mixed using a rotary mixer comprising a container rotating on itself as well as along a rotating plate, for 1 minute at a speed of 800 revolutions per minute.

[0079] Water is then added to the container and the formed dough is mixed for 1 minute at a speed of 800 revolutions per minute.

[0080] The resulting composition is left to stand for 2 minutes during which time the walls of the container are scraped in order to return all of the paste to the center of the container.

[0081] The dough is then mixed again for 1 minute at a speed of 800 revolutions per minute.

[0082] The samples corresponding to the examples are prepared according to the standard for tile adhesives EN 12004:2017, from a half-concrete slab covered half with the comparative composition detailed in Table 1 and, on the other half, with one of the compositions of the examples according to the invention.

[0083] 5 cm tile tiles 2 were deposited on the mortar composition after adding water.

[0084] After 7 days, disassembly tests were carried out by heating some samples using a heat gun placed 10 cm from the mortar. The temperature of the tile is measured using an infrared thermometer.

[0085] These tests demonstrate that the compositions of Examples 1 and 2 according to the invention allow disassembly of the tiles on the concrete slab. In these examples, the expansion of the graphite led to complete disassembly, without any remaining adhesion. The disassembly occurred smoothly, i.e. without ejection of the tile and allowing the tile to be recovered by hand.

[0086] It was observed that a break occurs in the middle of the mortar layer, since remnants of mortar composition appear on both the concrete slab and the tile. This demonstrates good wettability of the mortar paste and good transfer of it to the tile.

[0087] Any remaining mortar composition can be completely removed by continuing to heat the concrete slab and / or tile. When these residues are heated, the graphite continues to expand. The heated mortar can be easily removed after 2 minutes of heating using a heat gun placed 10 cm from it, or after a shorter time if the heat gun is placed less than 10 cm from the mortar. After this heating, the mortar no longer has any adhesive properties.

[0088] This disassembly is carried out in a sufficiently short time to be easily implemented.

[0089] The comparative example could not be disassembled and therefore it was not possible to recover the tile by hand after the test.

[0090] Adhesion tests were carried out after 28 days according to standard EN 12004:2017, at room temperature and after the action of heat, i.e. heating to 70°C.

[0091] The compositions of Examples 1 and 2 according to the invention exhibit at least satisfactory adhesion at room temperature, i.e. tensile adhesion of at least 0.5 MPa, corresponding to a class CL adhesive mortar.

[0092] The composition of Example 1 according to the invention also exhibits an adhesion after heating of at least 0.5 MPa, satisfactory for a class CL adhesive mortar.

[0093] The above examples therefore demonstrate that a mortar composition according to the invention allows easy disassembly by heating of a tile on a concrete slab while retaining satisfactory adhesion properties under normal conditions of use.

[0094] The comparison of Example 1 and the comparative example, of similar composition but devoid of thermally expandable material, demonstrates that a composition according to the invention, containing a thermally expandable material, retains adhesion properties at least equal to those of a comparable composition devoid of such material, while allowing easy disassembly.

[0095] Other example compositions were formulated and tested according to the protocols described for the previous examples, these and the test results are presented in Table 2 below. [Table 2]

[0096] The tests carried out demonstrate that each of the compositions of examples 3, 4 and 5 according to the invention allows disassembly of the tiles on the concrete slab qualitatively similar to that of examples 1 and 2 according to the invention.

[0097] For examples 3 and 4 according to the invention, this disassembly is carried out in a shorter time than that of examples 1 and 2. These examples therefore allow particularly easy use.

[0098] Example 5 demonstrates that a composition containing a lower content of thermally expandable material still allows for disassembly of a tile while retaining interesting adhesion properties. Such a composition is of interest in that it allows the cost of the dry mortar composition to be reduced.

[0099] All the compositions of the examples according to the invention exhibit at least satisfactory adhesion at room temperature, i.e. tensile adhesion of at least 0.5 MPa, corresponding to a class Cl adhesive mortar. The compositions of examples 3, 4 and 5 even exhibit satisfactory adhesion at room temperature for a class C2 adhesive mortar, i.e. of at least 1 MPa.

[0100] The compositions of examples 3, 4 and 5 according to the invention also exhibit an adhesion after heating of at least 1 MPa, satisfactory for a class C2 adhesive mortar.

[0101] The above examples therefore demonstrate that a mortar composition according to the invention allows easy disassembly by heating of a tile on a concrete slab while retaining satisfactory adhesion properties under normal conditions of use.

[0102] The composition of Example 4 is particularly advantageous in that it allows excellent adhesion properties to be obtained while offering particularly easy disassembly, requiring little time and heating.

Claims

Demands 1. Dry composition of tile adhesive mortar, comprising a mineral binder and at least one thermally expandable material.

2. Composition according to the preceding claim, for the formation of dried mortar suitable for expansion until rupture by heating at a temperature between 80 °C and 300 °C.

3. Composition according to any one of the preceding claims, wherein the mineral binder is a hydraulic binder, in particular selected from Portland cements, especially of type CEM I or CEM II, belitic cements, aluminous cements, sulfoaluminous cements, pozzolanic mixture cements, hydrated lime, slags, metakaolins, fly ash, calcium sulfate sources and mixtures of two or more of these binders.

4. Composition according to any one of the preceding claims, wherein the mineral binder is Portland cement, in particular present in a content of 10% to 50% by weight and preferably of 20% to 40% by weight relative to the total weight of the composition.

5. Composition according to any one of claims 1 to 3, wherein the mineral binder is a binder comprising, in particular, Portland cement, aluminous cement and a source of calcium sulfate.

6. Composition according to the preceding claim, wherein the source of calcium sulfate is selected from gypsum, calcium sulfate hemihydrate, calcium sulfate anhydrite and mixtures thereof, and preferably the source of calcium sulfate is a mixture of calcium sulfate hemihydrate and calcium sulfate anhydrite.

7. Composition according to any one of claims 5 or 6, wherein Portland cement is present in a content of 2% to 10% by weight, in particular 3% to 9% by weight and preferably 5% to 8% by weight relative to the total weight of the composition.

8. Composition according to any one of claims 5 to 7, wherein the aluminous cement is present in a content of 10% to 25% by weight, and preferably 15% to 20% by weight relative to the total weight of the composition.

9. Composition according to any one of claims 5 to 8, wherein the calcium sulfate source is present in a content of 2% to 10% by weight, in particular 4% to 9% by weight and preferably 6% to 8.5% by weight, relative to the total weight of the composition.

10. Composition according to any one of claims 5 or 6, said composition comprising at least one of the following characteristics: a. Aluminous cement is present in a content of 30% to 60% by weight and preferably of 35% to 55% by weight relative to the total weight of the composition, b. Portland cement is present in a content of 10% to 25% by weight, in particular 11% to 23% by weight, and preferably 12% to 20% by weight relative to the total weight of the composition, and / or c. The source of calcium sulfate is present in a content of 10% to 30% by weight, in particular 11% to 27% by weight and preferably 15% to 25% by weight, relative to the total weight of the composition.

11. Composition according to any one of the preceding claims, wherein the thermally expandable material is a thermally expandable graphite.

12. Composition according to any one of the preceding claims, wherein the thermally expandable material is present in a content of 0.3% to 10% by weight, in particular 0.4% to 7% by weight and preferably 0.5% to 5% by weight, relative to the total weight of the composition.

13. Composition according to any one of the preceding claims, further comprising at least one additive selected from retarders; accelerators such as calcium formate; rheological agents such as plasticizers and superplasticizers; biocidal preservatives; redispersible polymer powders such as polymer powders obtained from at least one monomer selected from vinyl esters, (meth)acrylates, (meth)acrylic acids, aromatic vinyls, alkenes, dienes and vinyl halides; water-retaining agents; air-entraining agents; thickening agents such as cellulose ethers and starch ethers; dispersing agents and pigments, in particular the additive(s) is / are present in a content of 0.01% to 6% by weight and preferably 0.1% to 4% by weight relative to the total weight of the composition.

14. Method of fixing a tile to a substrate, comprising successively: a. mixing the dry composition according to any one of the preceding claims with water so as to obtain a wet mortar, b. applying the wet mortar to said substrate, and c. applying the tiles of said tile to said substrate.

15. A method according to the preceding claim, wherein a quantity of water of 15% to 40% by weight and preferably 20% to 35% by weight, relative to the total weight of the wet mortar, is introduced into the mixture in step a).

16. A method for disassembling a tile obtained according to any one of claims 14 and 15, comprising a step of heating the mortar to a temperature of 80 °C to 300 °C, in particular from 85 °C to 250 °C and preferably from 90 °C to 225 °C, said heating step being carried out in particular by means of a heat gun, microwave or induction.

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