Dry mortar composition, particularly adhesive mortar

Abstract

Dry mortar composition, in particular adhesive mortar. The invention relates to a dry mortar composition, preferably adhesive mortar, having an uncompacted density between 900 g / L and 1400 g / L and comprising at least one air-entraining agent at a mass content between 0.1% and 2%. The invention also relates to a wet mortar obtained from mixing this dry mortar composition, as well as a method for fixing tiles to a substrate using this dry mortar composition.

Description

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

[0001] The present invention relates to a dry mortar composition, in particular a mortar-adhesive.

[0002] A dry mortar composition is a composition ready to be mixed with water. It is a powdered mixture containing one or more hydraulic binders, aggregates, and optional additives. After mixing with water (i.e., mixing), a paste is obtained, in other words, "wet mortar," which can be applied to a substrate (for example, a floor or a wall) or between building elements. After drying, the mortar hardens and thus bonds the materials together. It can also adhere to a substrate and form a surface layer on a wall or floor.

[0003] This is why mortar is used in many construction, renovation, and landscaping projects as a bonding, sealing, or plastering element. Depending on the nature of the construction work, its function is: - to assemble and bind together different building materials (for example bricks, masonry blocks, breeze blocks, aggregates); - to produce lightweight screeds, plaster, glue, grout, repair and seal various construction elements such as coping stones, tiles or natural or reconstituted stones.

[0004] Among the mortars is tile adhesive, which is a tile adhesive. The wet tile adhesive is applied to a substrate (for example, a concrete slab) to ensure that the tiles are fixed to it.

[0005] For the purposes of describing the present invention, the terms detailed below are defined as follows: - a "dry mortar composition" corresponds to mortar in powder form (or in other words in powder form); - The "uncompacted density" corresponds to the "apparent density" of the dry mortar composition. It is also called "bulk density". The uncompacted density can be measured according to the certification standard: Technical document 11-04 "Mortars and related products: Thin joint mounting mortars for small masonry elements" of March 14, 2022, revision no. 2, of the Scientific and Technical Center for Building (hereinafter abbreviated "CSTB"); - "Wet mortar" refers to the product obtained after mixing a dry mortar mix with water. It has a paste-like consistency; - "Paste density" refers to the density of wet mortar obtained after mixing a dry mortar mix. The paste density can be measured according to standard NF EN 1015-6.

[0006] The present invention is explained below with particular reference to adhesive mortars, without this limiting its scope.

[0007] Improving the environmental performance of buildings is a crucial issue for achieving carbon neutrality objectives. From the construction phase to the destruction or deconstruction of the building, the objective is to choose materials that reduce the environmental impact of buildings.

[0008] As explained above, the mortar, in particular the adhesive mortar, comprises one or more hydraulic binders which may include Portland cement.

[0009] However, the manufacture of Portland cement results in greenhouse gas emissions, primarily CO2, through the following two mechanisms: - Portland cement is composed of a mixture of limestone and clay. Clinkerization requires a temperature of 1450°C: the limestone then transforms into quicklime and CO2. The decarbonation of the limestone thus produces CO2 emissions; - The use of fuels to reach these high clinkerization temperatures also generates CO2 emissions. In this regard, cement manufacturers are seeking to limit fossil fuels and are developing the use of waste or biomass.

[0010] Cement-based mortars, in particular adhesive mortars, are then mixed with water and hardening is linked to dissolution-crystallization phenomena with the formation of different mineral phases such as hydrated calcium silicates, ettringite or portlandite.

[0011] These different phases have a recarbonation capacity. This means that upon contact with atmospheric CO2, these phases are modified and capture this CO2 in a sustainable manner. This natural recarbonation phenomenon occurs throughout the material's service life and therefore constitutes a primary means of reducing the carbon footprint associated with the manufacturing and use of cement-based materials.

[0012] However, the natural recarbonation of a tile adhesive is severely limited by the low gas permeability of said tile adhesive due to its low porosity, which hinders gas diffusion. However, tile adhesives currently on the market, hereinafter referred to as "conventional tile adhesives," are not optimized in terms of paste density and porosity to facilitate CO2 diffusion. through the adhesive mortar for better propagation of recarbonation under the tiles.

[0013] To facilitate the diffusion of CO2 through the adhesive mortar, one solution could be to lower the paste density of conventional adhesive mortars, which is currently between 1,500 g / L and 1,700 g / L. Such adhesive mortars already exist, hereinafter referred to as "lightweight adhesive mortars," because they have lower paste densities, generally between 1,100 g / L and 1,300 g / L. However, this solution is not satisfactory because the reduction in paste density is achieved by adding lightweight fillers, also known as "low-density fillers." For the purposes of this invention, "low-density fillers" means fillers with an apparent density of no more than 600 kg / m³. For example, these could be closed, hollow particles such as expanded glass particles. However, it turns out that these lightweight fillers slow down the diffusion of CO2 through these lightweight adhesive mortars.

[0014] Furthermore, in addition to increasing the recarbonation of the adhesive mortar, another area for improvement to reduce its carbon footprint and environmental impact could be based on increasing its yield.

[0015] For the purposes of this invention, "mortar yield" means the mass of dry mortar composition required to satisfactorily apply said mortar to 1 m² of substrate. Thus, in the case of adhesive mortar, the adhesive mortar yield is the mass of dry adhesive mortar composition required to satisfactorily fix 1 m² of tiles to a substrate.

[0016] Improving the yield of the adhesive mortar thus implies less packaging, transport, and use of critical raw materials such as silica sands per m2 of adhesive mortar applied.

[0017] Now, returning to the lightweight tile adhesives presented above, these, thanks to their low paste densities, certainly offer a better yield than conventional tile adhesives for the same mass of dry composition. However, due to the presence of lightweight fillers in their dry composition, their volume (i.e., their volume of powder) for the same mass is much greater than that of a conventional tile adhesive. Bags of lightweight tile adhesives should therefore be almost twice the size of those of conventional tile adhesives; this is not feasible for reasons of ergonomics and handling for the operator or for transport. This is why lightweight tile adhesives are mainly sold in 15 kg bags, with a yield per bag ultimately close to that of a conventional tile adhesive sold in 25 kg bags.

[0018] The inventors of the present invention sought to overcome all these drawbacks detailed above with regard to so-called "classic" and "lightweight" adhesive mortars, by developing a new dry mortar composition, in particular adhesive mortar, for which the carbon balance of said mortar and its impact on the environment are reduced thanks to the following two areas of improvement: - the diffusion of CO2 through the mortar is facilitated for a better propagation of recarbonation (and therefore in particular the diffusion of CO2 through the adhesive mortar under the tiles); - the yield of the mortar is increased without increasing the volume of powders required (in other words the volume of the dry mortar composition); which allows for better industrial and logistical efficiency.

[0019] The invention thus has as its first object a dry mortar composition, preferably a mortar-adhesive, having an uncompacted density of between 900 g / L and 1,400 g / L, preferably between 1,000 g / L and 1,300 g / L and characterized in that it comprises at least one air-entraining agent at a mass content expressed in relation to the total mass of said dry mortar composition of between 0.1% and 2%, preferably between 0.2% and 0.9%.

[0020] For the purposes of describing the present invention, an "air-entraining agent" is defined as an agent designed to reduce the surface tension of water during the preparation of wet mortar (i.e., during mixing). More specifically, during mixing, the air-entraining agent positions itself at the water-air interface. This improves the dispersion of the dry mortar composition in the water, as well as the stability of the wet mortar paste obtained after mixing. During mixing, fine air bubbles are drawn in. The air-entraining agent improves the workability of the mortar by lightening the wet mortar paste and making it perfectly stable. Indeed, thanks to the air-entraining agent, the air injected into the wet mortar during mixing remains "trapped" within the wet mortar and allows a network of pores to develop as the material (i.e., the mortar) hardens.

[0021] In the construction industry, it is already known to use air-entraining agents in application products, such as facade plasters, where they help control the homogeneity of the mortar's porosity, thereby improving its resistance to freeze-thaw cycles. Furthermore, particularly for repair mortars, air-entraining agents soften the mortar and facilitate its mixing and application to the substrate. However, for these various applications of facade plaster or repair mortars, the mass content of the air-entraining agent must be limited to avoid degrading the mortar's mechanical strength. In this regard, it is generally recommended that this mass content not exceed 0.05% (this mass content being expressed as a percentage of the total mass of the composition). mortar dry). Furthermore, it is known that an excess of air-entraining agent generally causes instability of the entrained air.

[0022] As regards adhesive mortars, their dry compositions generally do not contain such air-entraining agents, because they instead include thickening agents and redispersible polymers which also entrain a certain amount of air during the mixing of the adhesive mortar and which are sufficient to improve the workability of the adhesive mortar.

[0023] The originality of the present invention therefore lies in the presence of at least one air-entraining agent in the dry mortar composition at a mass content much higher (namely 10 to 20 times higher) than that generally used in dry mortar compositions known in the state of the art.

[0024] The presence of a very large quantity of the air-entraining agent in the dry composition of the mortar according to the invention makes it possible to significantly reduce the density of the paste compared to that of the conventional adhesive mortars mentioned above. This gives the following advantages to the mortar according to the invention: - the incorporation of a much larger quantity of air into the wet mortar paste and the improvement of the distribution of air bubbles in said paste during mixing; - the increase in the porosity of the hardened mortar which facilitates the diffusion of CO2 through the mortar under the tiles and, consequently, improves the amount of CO2 captured during the mortar's service life; which contributes to reducing its carbon footprint; Because the uncompacted density of the dry mortar composition is close to that of a conventional tile adhesive, a larger bonding surface can be covered with the same volume of powder (i.e., the same volume of dry mortar composition) and the same bag weight as a conventional tile adhesive (namely 25 kg). The yield of the mortar according to the invention is therefore improved, reducing the industrial impacts related to transport and packaging materials in its overall environmental footprint.

[0025] It is important to emphasize that the dry mortar composition according to the invention has been developed to incorporate a significant amount of air during mixing in order to lower the paste density without having to add lightweight fillers. This air entrainment is precisely controlled in order to: - to obtain a homogeneous distribution of air bubbles in the wet mortar paste during mixing and that the wet mortar remains stable (i.e. that the air carried in during mixing does not escape, or at least to a lesser extent, from the wet mortar paste); - to avoid any instability of the entrained air which, as explained above, can occur in case of excess of air entraining agent.

[0026] During experiments on a dry composition of adhesive mortar according to the invention, the inventors were able to observe the following remarkable advantages: - an improvement in the depth of recarbonation of 40% over the service life of said mortar; which contributes to increasing the recarbonation per m2 by 100% compared to a conventional adhesive mortar of the same classification; - an increase of at least 75% in the m2 bonded with the adhesive mortar according to the invention, for the same mass and the same size of bag compared to a conventional adhesive mortar; which implies a reduction in the arduousness on site for the same surface area of ​​adhesive mortar applied (namely fewer bags, therefore less load carrying, a very light consistency of the adhesive mortar therefore ease of application and mixing).

[0027] The various constituents of the dry mortar composition according to the invention are now described in more detail.

[0028] The dry mortar composition according to the invention comprises at least one air-entraining agent. As explained above, these air-entraining agents are known to those skilled in the art in the construction field. The air-entraining agent is an agent designed to reduce the surface tension of water during the preparation of wet mortar by positioning itself at the water-air interface. Therefore, the air-entraining agent can be chosen from anionic, cationic, nonionic, or amphoteric surfactants.

[0029] The air-entraining agent can be selected from: - anionic surfactants, for example alkyl sulfates, alkyl ether sulfates, alkaryl sulfonates, alkylsuccinates, alkylsulpho succinates, alkoyl sarcosinates, alkyl phosphates, alkylether phosphates, alkylether carboxylates and alpha-olefin sulfonates; - non-ionic surfactants, for example ethoxylated fatty alcohols, mono- or di-alkyl alkanolamides, alkyl polyglucosides; - Amphoteric surfactants, for example alkyl amine oxides, alkyl betaines, alkyl amido propyl betaines, alkyl sulfo betaines, alkyl glycinates, alkyl amphopropionates and alkyl amidopropyl hydroxysultaines.

[0030] Preferably, the air-entraining agent is chosen from: - sodium alkyl sulfates (for example, agents marketed by Ashland under the trade names Silipon® RN6031 and RN 6068), - sodium alpha olefin sulfonates (for example, agents marketed by Ashland under the trade name Silipon® RN 7002 or by Clariant under the trade name Hostapur OSB), - ethoxylated fatty alcohols (for example the agent marketed by the company Ashland under the trade name Silipon® RN 8018).

[0031] As explained above, the mass content of air-entraining agent expressed in relation to the total mass of the dry mortar composition is between 0.1% and 2%, preferably between 0.2% and 0.9%.

[0032] The dry mortar composition according to the invention comprises at least one hydraulic binder.

[0033] The hydraulic binder can be chosen from: - cements, preferably Portland cements (more preferably those conforming to the European standard EN 197-1), aluminous and / or sulfo-aluminous cements, - calcium sulfates (natural or synthetic gypsum, calcium sulfate hemihydrate, anhydrite), - silico-aluminous binders, fly ash, metakaolins, crushed granulated blast furnace slags, calcined clays.

[0034] As an example of Portland cement, it may be Portland cement marketed under the trade name PERFORMAT® CEM I 52.5 R CE CP2 NF by the company Vicat or Portland cement CEM II / A-LL 52.5 R CE CP2 NF marketed by the company Holcim or Portland cement CEM I 52.5 R CE CP2 NF marketed by the company Calcia.

[0035] As an example of aluminous and / or sulfoaluminous cement, it may be the cement marketed under the trade name ALPENAT CK by the company Vicat or the cement marketed under the trade name FONDU® by the company Imerys.

[0036] As an example of calcium sulfate, it may be natural semi-hydrated gypsum marketed under the trade name Molda 3 N by the company Formula Saint Gobain or synthetic calcium sulfate marketed under the name CAB 30 by the company Lanxess.

[0037] As an example of ground granulated blast furnace slag, this could be ground granulated blast furnace slag marketed by the company Ecocem. Ground granulated blast furnace slag contributes to improving the mechanical strength of the mortar.

[0038] The mass content of at least one hydraulic binder, expressed in relation to the total mass of the dry mortar composition, can be between 10% and 99%, preferably between 40% and 80%.

[0039] The dry mortar composition according to the invention may further comprise at least one sand, for example siliceous, calcareous, silico-calcareous or magnesian sands.

[0040] For example, this could be silica sand marketed under the trade name BE32 by the company Sibelco or silica sand marketed under the trade name PE2LS by the company Fulchiron.

[0041] The mass content of at least one sand, expressed in relation to the total mass of the dry mortar composition, can be between 0.1% and 85%, preferably between 5% and 40%.

[0042] The dry mortar composition according to the invention may further include at least one setting accelerator additive.

[0043] The setting accelerator additive can be chosen from: - alkali and alkaline earth salts of hydroxides, halides, nitrates, nitrites, carbonates, thiocyanates, sulfates, thiosulfates, perchlorates, silica, aluminium, preferably among chlorides and their sodium or calcium salts, carbonates and their sodium or lithium salts, sulfates and their sodium or potassium salts, calcium hydroxides and formates, - Carboxylic and hydrocarboxylic acids and their salts, - alkanolamines, - insoluble silicate compounds such as silica fume, fly ash or natural pozzolans, quaternary ammonium silicates, - finely divided mineral compounds such as silica gels or finely divided calcium and / or magnesium carbonates, - hydrated calcium silicate nuclei, - amorphous calcium aluminates.

[0044] The mass content of at least one setting accelerator additive, expressed in relation to the total mass of the dry mortar composition, can be between 0.01% and 8%, preferably between 0.5% and 5%.

[0045] The dry mortar composition according to the invention may further include at least one setting retardant additive.

[0046] The setting retardant additive can be chosen from carboxylic acids and their salts, polysaccharides and their derivatives, borates and their salts, citric acid and its salts, sodium gluconates, tartaric acid and its salts.

[0047] The mass content of at least one setting retarder additive, expressed in relation to the total mass of the dry mortar composition, may be between 0.001% and 2%, preferably between 0.01% and 0.3%.

[0048] The dry mortar composition according to the invention may further comprise at least one thickener.

[0049] The thickener can be chosen from polysaccharides such as cellulose or starch ethers, preferably methylcelluloses, hydroxyethylcelluloses, methylhydroxypropylcelluloses, modified or unmodified methylhydroxyethylcelluloses, guar ethers, mineral thickeners and polyacrylamides.

[0050] As an example of thickeners, we can cite the thickener marketed under the trade name Culminai® UP 1540 by the company Ashland or the thickener marketed under the trade name WALOCEL® MKX 40000 PF 01 by the company Dow Chemical.

[0051] The mass content of at least one thickener, expressed in relation to the total mass of the dry mortar composition, may be between 0.05% and 4%, preferably between 0.3% and 2%.

[0052] The dry mortar composition according to the invention may further comprise at least one redispersible polymer.

[0053] The redispersible polymer can be chosen from homo- or copolymers of ethylene-vinyl acetate, acrylics, styrene butadiene, styrene acrylic, vinyl acetate and polyvinyl alcohol.

[0054] As an example of redispersible polymers, we can cite the polymer based on copolymers of vinyl acetate and ethylene marketed by the company Celanese under the trade name MP2100.

[0055] The mass content of at least one redispersible polymer, expressed in relation to the total mass of the dry mortar composition, can be between 0.1% and 20%, preferably between 1% and 10%.

[0056] The dry mortar composition according to the invention may further comprise at least one light filler as defined above. This may, for example, consist of expanded perlite, expanded glass, silica aerogels, expanded polystyrene, cenospheres, hollow alumina beads, expanded clays, pumice, hollow glass beads, silicate foam granules, or rhyolite.

[0057] If the dry mortar composition according to the invention comprises at least one light filler, the mass content of the light filler, expressed as a percentage of the mass of the dry mortar composition, may not exceed 10%, preferably 5%, more preferably 2%, even more preferably 1%, most preferably 0.5%, and most preferably 0.1%. This mass content of light fillers is considerably lower than that of the lightweight tile adhesives mentioned above, for which a high content of these light fillers hinders the diffusion of CO2 within the tile adhesive under the tiles.

[0058] However, preferably, the dry mortar composition is free of light fillers. By "free of light fillers," it is understood in the context of the present invention that the mass content of light fillers, expressed as a percentage of the total mass of the dry mortar composition, does not exceed 0.01%.

[0059] The dry mortar composition according to the invention may include other additives, referred to as "additional additives," than those detailed above. For example, these may be additional additives selected from fibers, water repellents, colorants, gas-generating agents, foaming agents, and fluidizing agents.

[0060] The colorants can be chosen from organic and / or mineral pigments, (preferably oxides of iron, titanium, chromium, tin, nickel, cobalt, zinc, antimony), sodium aluminosilicate polysulfides, carbon, cobalt, manganese, zinc sulfides, as well as pigments with high transparency or high infrared reflectance.

[0061] The mass content of these additional additives, expressed in relation to the total mass of the dry mortar composition, can be between 0.001% and 5%, preferably between 0.01% and 1%.

[0062] In one embodiment of the invention, the dry mortar composition may comprise, in mass percentages expressed relative to the total mass of said dry mortar composition: - between 0.1% and 2%, preferably between 0.2% and 0.9%, of at least one air-entraining agent, - between 10% and 99%, preferably between 40% and 80%, of cement, - between 0.05% and 4%, preferably between 0.3% and 2% of thickener, - optionally ground granulated blast furnace slag and, if present in said composition at a mass percentage not exceeding 90%, preferably between 5% and 60%, - optionally sand and, if present in said composition at a mass percentage not exceeding 85%, preferably between 5% and 30%, - optionally a setting accelerator additive and, if present in said composition at a mass percentage not exceeding 11%, preferably between 1.5% and 7%.

[0063] The various technical characteristics of the constituents of the dry mortar composition according to the invention which have been described above can of course be combined with each other in any possible combinations.

[0064] The dry mortar composition according to the invention is preferably a dry mortar-adhesive composition (namely a tile adhesive).

[0065] The dry mortar composition according to the invention can also be a dry mortar composition for assembly (i.e. for the assembly and mounting of masonry materials), for exterior and interior plastering, for bonding for exterior insulation systems.

[0066] The dry mortar composition according to the invention is preferably stored in bags with a capacity of 25 kg of said dry mortar composition.

[0067] The dry mortar composition according to the invention makes it possible to produce, after mixing, a wet mortar that is particularly pleasant and easy for the operator to apply, without too much effort. The wet mortar thus obtained after mixing has a smooth, creamy, and slightly foamy texture.

[0068] Therefore, the invention also relates to a wet mortar characterized in that it is obtained by mixing a dry mortar composition according to the invention as described above with water. The wet mortar has a paste density that is preferably between 700 g / L and 1400 g / L, more preferably between 1000 g / L and 1200 g / L.

[0069] The air volume content expressed in relation to the total volume of said wet mortar according to the invention is advantageously between 30% and 70%, preferably between 40% and 55%.

[0070] The 30-minute loss of paste density in the wet mortar according to the invention is less than 100 g / L, which is a threshold value established in the certification standard: Technical Document 11-03 "Mortars and related products: Single-layer plaster mortars" of March 14, 2022, revision no. 2, from the CSTB (French Scientific and Technical Center for Building) for facade plaster mortars in order to define the stability of wet mortar. The wet mortar according to the invention therefore perfectly meets this stability criterion.

[0071] The consistency of the wet mortar according to the invention is advantageously between 20 mm and 45 mm. The consistency of a wet mortar is determined using a penetrometer. This involves measuring the penetration of a penetrometer probe into a sample of the wet mortar over a given time. The higher the measured penetration value (expressed in mm), the more fluid the consistency of the wet mortar. Conversely, the lower this penetration value, the heavier and thicker the wet mortar.

[0072] The invention also relates to a method for preparing a wet mortar according to the invention which is characterized in that a dry mortar composition according to the invention as described above is mixed with water.

[0073] Preferably, the mixing is mechanical and can advantageously be carried out with an electric mixer.

[0074] The rotation speed of the electric mixer must be sufficient to ensure that the dry mortar composition is mixed effectively with the water to prevent lumps from forming and to allow air to be incorporated into the wet mortar paste. Adjusting the electric mixer to obtain a suitable mixture of the dry mortar composition with water is perfectly within the capabilities of a person skilled in the art.

[0075] The rotation speed of the electric mixer is advantageously between 400 rpm and 1100 rpm, preferably between 600 rpm and 900 revolutions per minute. A speed greater than 600 revolutions per minute improves the amount of air introduced into the wet mortar paste and thus maximizes the yield obtained with the mortar according to the invention.

[0076] The mixing time must be sufficient to allow the wet mortar paste to be homogenized and air to be incorporated. The mixing time with the electric mixer can be between 1 and 5 minutes, preferably between 2 and 3 minutes. Most preferably, the mixing time is 3 minutes. This makes it possible to obtain a mortar according to the invention with optimal characteristics, in particular those described above (for example, with regard to consistency).

[0077] Thus, in an advantageous embodiment of the invention, the process for preparing a wet mortar according to the invention is characterized in that a dry mortar composition according to the invention is mixed with water using an electric mixer whose rotation speed is between 400 rpm and 1,100 rpm, preferably between 600 rpm and 900 rpm, for a period of between 1 minute and 5 minutes, preferably between 2 minutes and 3 minutes.

[0078] In the context of the present invention, "mixing ratio" means the weight ratio between the water and the dry composition of mortar used during mixing.

[0079] The mixing ratio is determined by the operator according to the desired consistency of the wet mortar. Selecting the mixing ratio is perfectly within the capabilities of a person skilled in the art. Advantageously, the operator chooses a mixing ratio that results in a wet mortar with a consistency between 20 mm and 45 mm.

[0080] As an example, the waste rate can be between 0.45 and 0.55.

[0081] Regarding the characteristics of the electric mixer, it can have different whisk geometries, which can be single or double. These include a 4-blade USG whisk, a helical whisk, a right-hand helical hexagonal whisk, a left-hand helical hexagonal whisk, a propeller whisk, a high-shear force whisk, or a 5 QT wire whisk. Among these whisk models, some have blades that promote air incorporation and are particularly suitable for achieving optimal efficiency. These include the helical whisk, the right-hand helical hexagonal whisk, the left-hand helical hexagonal whisk, and the 5QT wire whisk, which are preferred in the context of the invention.

[0082] It should be noted that the search for an air drive with a mixing tool, for example with a mixing tool chosen from those described above, is counterintuitive for the person in the trade who would usually seek to limit the incorporation of air during mixing so as not to alter the nature of the mortar.

[0083] Advantageously, a flat-bottomed container is used to mix the dry mortar composition with water. This can be a bucket or a trough. Buckets with a diameter and height of 357 mm x 370 mm provide the best results for mixing the wet mortar paste (namely, a reduction in lumps and optimal yield). These buckets are well known to those skilled in the art.

[0084] As explained above, the dry mortar composition is preferably a dry mortar-adhesive composition. Mixing the dry mortar-adhesive composition yields a wet mortar-adhesive according to the invention, preferably having the technical characteristics described above.

[0085] Therefore, another object of the invention is a method for fixing tiles to a support which is characterized in that it comprises at least the following steps: - a dry mortar-adhesive composition according to the invention as described above is mixed with water to obtain a wet mortar-adhesive according to the invention as described above, preferably as described above for the preparation of a wet mortar according to the invention; - the said wet adhesive mortar is applied to the substrate and / or to the tiles; - the tiles are applied to the said support.

[0086] As explained above, mixing can be done with an electric mixer whose rotation speed is between 400 rpm and 1100 rpm, preferably between 600 rpm and 900 rpm, for a period of between 1 minute and 5 minutes, preferably between 2 minutes and 3 minutes.

[0087] The substrate can be a wall, a partition, or a floor (e.g., a screed). The tiles can be in the form of individual tiles or tile slabs. The tile material can be chosen, for example, from ceramic, stoneware, cement, stone, or marble. The wet mortar can, for example, be applied to the substrate and / or the tiles using a notched trowel, a float, a trowel, or a notched spatula.

[0088] The application of the wet adhesive mortar to the substrate and / or to the tiles, as well as the application of the tiles to the substrate, are steps perfectly within the reach of a person skilled in the art.

[0089] The invention will be better understood with the aid of the detailed description of experiments carried out with a dry composition of mortar-adhesive according to the invention and two comparative dry compositions of mortar-adhesive.

[0090] EXPERIMENTAL SECTION:

[0091] Experiments were carried out with: - a dry composition of mortar-adhesive according to the invention and hereinafter referred to as "invention mortar"; - a dry composition of classic adhesive mortar and hereinafter referred to as "comparative mortar 1"; - a dry composition of lightweight adhesive mortar and hereinafter referred to as "comparative mortar 2".

[0092] The dry mortar composition according to the invention comprised in mass percentages expressed in relation to the total mass of said dry composition: - 40% of CEM II 52.5R cement (1st hydraulic binder); - 35% crushed granulated blast furnace slag (2nd hydraulic binder); - 4% vinyl acetate and ethylene copolymer (redispersible polymer); - 19.85% BE32 sand (silica sand 0.2-0.5mm); - 0.35% sodium alpha olefin sulfonate (air-entraining agent); - 0.8% hydroxymethylcellulose 50000-60000 mPa (thickener);

[0093] This dry mortar-adhesive composition according to the invention has been classified “C2E” according to the standard NF EN 12004-1:2017.

[0094] The conventional dry mortar-adhesive composition was a dry mortar-adhesive composition marketed by Vicat Produits Industriels under the trade name V350 Collimix Fluid. This comparative dry mortar-adhesive composition 1 was classified as "C2E" according to standard NF EN 12004-1:2017.

[0095] The lightweight dry mortar-adhesive composition was a dry mortar-adhesive composition marketed by Vicat Produits Industriels under the trade name V430 / V431 Colliflex confort. This comparative 2 dry mortar-adhesive composition was classified as "C2S1E" according to standard NF EN 12004-1:2017.

[0096] The dry mortar compositions according to the invention, comparator 1 and comparator 2, were mixed according to a mixing ratio specified in Table 1 below with an electric mixer having a right-hand helical hexagonal geometry blade for a period of 3 minutes and at a mixing speed of 810 revolutions per minute so as to obtain wet mortars according to the invention, comparator 1 and comparator 2.

[0097] Table 1 below provides details for the invention mortar and comparative mortars 1 and 2: - the uncompacted density which was determined according to the aforementioned certification standard, namely Technical Document 11-04 "Mortars and related products: Thin joint mounting mortars for small masonry elements" of March 14, 2022, revision no. 2, from the CSTB; - the mixing ratio used to obtain the wet mortar; - the apparent density of the paste which was determined according to the standard NF EN 1015-6; - the stability of the paste at 30 minutes which was determined according to the aforementioned certification standard, namely Technical Document 11-03 "Mortars and related products: Single-layer plaster mortars" of March 14, 2022, revision no. 2, from the CSTB; - yield in m2 for a double-bonding application on tiles and a concrete slab with a U9 notched trowel for a 25 kg bag; - yield in m2 for a double-bonding application on tiles and a concrete slab with a U9 notched trowel for a 15 kg bag; - the consistency expressed in mm and as defined above.

[0098] [Tables 1] Comparative Mortar 1 Snyenïson Mortar Comparative Mortar 2 Bulk Density (g / L) 1300 1150 SQO Mixing Ratio (%) 26 52 44 Paste Density (g / L) 1650 1100 1300 Paste Stability after 30 minutes (g / L) 1660 E1C (g / L) 1112 [U2 (g / L) 1308 hS (g / L) Consistency (mm) 37 33 36 Yield per 25 kg bag (m2) S 7 9.2 7 Yield per 15 kg bag (m2) 3.12 5.52 4.2

[0099] In view of the results detailed in Table 1, it can be noted that: The mortar according to the invention has a bulk density relatively close to that of comparative mortar 1 (namely, conventional tile adhesive) and a significantly lower paste density (1100 g / L versus 1650 g / L). Its paste density is even lower than that of comparative mortar 2 (namely, lightweight tile adhesive). This demonstrates that the presence of a significant amount of air-entraining agent (0.35%) allows for a reduction in paste density, even without the addition of fillers (particularly light fillers). - The wet mortar according to the invention remains perfectly stable after 30 minutes compared with comparative mortars 1 and 2. - The invention mortar shows better yields for 25 kg and 15 kg bags than comparative mortars 1 and 2.

[0100] Two types of models were prepared with the invention mortar and the comparative mortar 1 for use in recarbonation experiments.

[0101] The first model was a tiled model and was obtained in the following manner:

[0102] The tested adhesive mortar (namely invention or comparator 1) was applied using a 20 mm half-moon comb in single bonding on a square (51cm x 51cm) fiber cement board.

[0103] A square (50 cm x 50 cm) porcelain stoneware tile with a thickness of 1 cm was positioned and pressed onto the tested adhesive mortar.

[0104] After 16 hours of drying, the model was grouted around its perimeter using a commercially available cement-based grout. The joint width was 5 mm.

[0105] After 7 days of drying, the model was gas-tightened using a two-layer epoxy resin in order to have only the upper surface of the model in contact with CO2.

[0106] The 2nd model was a prism model and was obtained in the following manner:

[0107] The tested adhesive mortar (namely invention or comparator 1) was applied in a mold having the shape of a prism with dimensions 4 cm x 4 cm x 16 cm.

[0108] The prisms were demolded after 24 hours of drying. Then, after 7 days of drying at 23°C, the faces were gas-tightened using a two-layer epoxy resin, so that only one 4 cm x 4 cm face of the prism was in contact with CO2.

[0109] The first and second models were placed under accelerated aging conditions in an oven with the following parameters: - CO2 volume content: 3%; - temperature of 20°C; - humidity of 65%.

[0110] Several samples were taken from the 1st and 2nd models at several deadlines.

[0111] The CO2 capture measurement was carried out by thermogravimetric analysis.

[0112] To do this, the mass loss of the sample was measured at different temperatures. Free water or water present in certain hydrates, as well as organic matter, are released between 80 and 600°C. Between 600 and 900°C, only fixed CO2 is released.

[0113] However, sands or limestone aggregates also release their CO2 over this same temperature range. Therefore, it was necessary to prepare a so-called "control" sample with the same batches of the tested mortars, which was allowed to harden in a pillbox protected from CO2 from the air (therefore without the possibility for the tested adhesive mortars to capture CO2 from the air) in order to be able to measure for this control sample the quantity of CO2 released by the sands and limestone fillers when they are subjected to temperatures between 600°C and 900°C.

[0114] Then, after subtracting this quantity of CO2 released by the sands and limestone fillers at these high temperatures, it was possible to deduce the quantity of CO2 actually captured by recarbonation by the tested adhesive mortars.

[0115] The depth of recarbonation of the tested adhesive mortars was also determined with these samples.

[0116] A pH indicator (phenolphthalein) was applied to raise the recarbonation front.

[0117] The recarbonation results obtained with the 1st and 2nd models are detailed below.

[0118] Recarbonation results with the 1 — model (prism):

[0119] The prisms were removed from the recarbonation oven at different times. They were then cut lengthwise, and the aforementioned pH indicator was applied to reveal the recarbonation front and thus measure the depth of recarbonation.

[0120] Table 2 below details for the invention mortar and the comparative mortar 1 the depth of recarbonation (expressed in mm) as a function of the number of days under the accelerated aging conditions detailed above.

[0121] The second column of Table 2 shows the correspondence between these number of days under accelerated aging conditions and their equivalent number of days under natural conditions. This correspondence can be easily determined by considering that the CO2 volume concentration in the oven was 3% and that in the air is approximately 357 ppm. 7 days under accelerated aging conditions correspond to 588 days (84 weeks) under natural conditions. 31 days under accelerated aging conditions correspond to 2604 days (372 weeks, slightly more than 7 years) under natural conditions. 97 days under accelerated aging conditions correspond to 8148 days (1164 weeks, slightly more than 22 years) under natural conditions.

[0122] [Tables2] Number of days under accelerated conditions Equivalent number of days under natural conditions Recarbonation depth of comparative mortar 1 (in mm) Recarbonation depth of invention mortar (in mm) / 588 15 22 31 26C4 37 55 97 8148 54 75

[0123] In view of the detailed results in Table 2, it is noted that the invention mortar exhibits a greater depth of recarbonation than that of the comparative mortar 1.

[0124] The service life of the adhesive mortars is approximately 50 years. This value is used as a reference on the environmental and safety data sheets for these construction products.

[0125] Therefore, from linear regressions established from the results detailed in Table 2 above, it was determined that after 50 years under natural conditions, the depth of recarbonation of: - invention mortar is 117 mm, - comparative mortar 1 is 83 mm.

[0126] The invented mortar exhibits a better depth of recarbonation after 50 years under natural conditions than the comparative mortar 1.

[0127] Thus, the diffusion of CO2 in the invention mortar is 40% faster and deeper than that of the comparative mortar 1.

[0128] Recarbonation results with the 2 — model (tile):

[0129] The samples were taken after 3 months under accelerated aging conditions, i.e. approximately 21 years in natural equivalent conditions.

[0130] Samples were taken on the diagonal of the porcelain stoneware tile (50 cm on each side) at the following distances measured from the corner of the tile: 5 cm, 20 cm and 35 cm.

[0131] Table 3 below details the quantity of CO2 captured by the tested adhesive mortar at the sampling point (namely on the tile diagonal at 5 cm, 20 cm and 35 cm). This quantity is expressed in kg of CO2 captured, normalized to one tonne of dry composition of the tested adhesive mortar (i.e., "kg CO2 / t. equivalent").

[0132] [Tables3] Quantity of CO captured (kg COs / t equivalent) along the diagonal of the tile at: Mortar invention Comparative mortar 1 5 cm 102 33.1 20 cm 14.9 13.3 35 cm 4.8 2.6

[0133] These results were processed using mathematical methods to model recarbonation across the entire porcelain stoneware tile and to deduce an average value for the amount of CO2 captured after these 3 months under accelerated aging conditions (or 21 years under natural conditions) for: - the invention mortar: 58 kg CO2 / t. equivalent; - Comparative mortar 1: 17 kg CO2 / t. equivalent.

[0134] In view of the yields in m2 detailed in Table 1 above for the invention mortar and the comparative mortar 1 and in view of these average values ​​of the quantity of CO2 captured, it can be deduced that for 1 m2 of adhesive mortar applied using a U9 notched trowel: - 0.08 kg of CO2 are recarbonated with the comparative mortar 1, - 0.157 kg of CO2 are recarbonated with the invention mortar,

[0135] after 3 months under accelerated aging conditions (or 21 years under natural conditions). The amount of CO2 captured after 3 months under accelerated aging conditions (or 21 years under natural conditions) is therefore twice as high with the invention mortar as with the comparative mortar 1.

Claims

Demands

1. Dry mortar composition, preferably adhesive mortar, whose uncompacted density, measured according to the certification standard: Technical Document 11-04 "Mortars and related products: Thin joint mounting mortars for small masonry elements" of March 14, 2022, revision no. 2, of the Scientific and Technical Center for Building, is between 900 g / L and 1,400 g / L, preferably between 1,000 g / L and 1,300 g / L, characterized in that it comprises at least one air-entraining agent at a mass content expressed in relation to the total mass of said dry mortar composition of between 0.1% and 2%, preferably between 0.2% and 0.9%.

2. Dry mortar composition according to claim 1, characterized in that at least one air-entraining agent is selected from alkyl sulfates, alkyl ether sulfates, alkaryl sulfonates, alkylsuccinates, alkylsulpho succinates, alkoyl sarcosinates, alkyl phosphates, alkylether phosphates, alkylether carboxylates, alpha-olefin sulfonates, ethoxylated fatty alcohols, mono- or di-alkyl alkanolamides, alkyl polyglucosides, alkyl amine oxides, alkyl betaines, alkyl amidopropyl betaines, alkyl sulfo betaines, alkyl glycinates, alkyl amphopropionates and alkyl amidopropyl hydroxysultaines.

3. Dry mortar composition according to claim 2, characterized in that at least one air-entraining agent is selected from sodium alkyl sulfates, sodium alpha olefin sulfonates and ethoxylated fatty alcohols.

4. Dry mortar composition according to any one of claims 1 to 3, characterized in that it comprises at least one hydraulic binder selected from cements, calcium sulfates, silico-aluminous binders, fly ash, metakaolins, ground granulated blast furnace slags and calcined clays.

5. Dry mortar composition according to claim 4, characterized in that the mass content of at least one hydraulic binder, expressed in relation to the total mass of the dry mortar composition, is between 10% and 99%, preferably between 40% and 80%.

6. Dry mortar composition according to any one of claims 1 to 5, characterized in that it further comprises at least one thickener selected from cellulose or starch ethers, preferably methylcelluloses, hydroxyethylcelluloses, methylhydroxypropylcelluloses, modified or unmodified methylhydroxyethylcelluloses, guar ethers, mineral thickeners and polyacrylamides.

7. Dry mortar composition according to claim 6, characterized in that the mass content of at least one thickener, expressed in relation to the total mass of said dry mortar composition, is between 0.05% and 4%, preferably between 0.3% and 2%.

8. Dry mortar composition according to any one of claims 1 to 7, characterized in that it further comprises at least one redispersible polymer selected from homo- or copolymers of ethylene-vinyl acetate, acrylics, styrene butadiene, styrene acrylic, vinyl acetate and polyvinyl alcohol.

9. Dry mortar composition according to claim 8, characterized in that the mass content of at least one redispersible polymer, expressed in relation to the total mass of the dry mortar composition, is between 0.1% and 20%, preferably between 1% and 10%.

10. A dry mortar composition according to claim 1, characterized in that it comprises, in mass percentages expressed relative to the total mass of said dry mortar composition: - between 0.1% and 2%, preferably between 0.2% and 0.9%, of at least one air-entraining agent, - between 10% and 99%, preferably between 40% and 80%, of cement, - between 0.05% and 4%, preferably between 0.3% and 2%, of thickener, - optionally ground granulated blast furnace slag and, if present in said composition at a mass percentage not exceeding 90%, preferably between 5% and 60%, - optionally sand and, if present in said composition at a mass percentage not exceeding 85%, preferably between 5% and 30%, - optionally a setting accelerator additive and, if present in said composition at a mass percentage not exceeding 11%, preferably between 1.5% and 7%.

11. Dry mortar composition according to any one of claims 1 to 10, characterized in that it is free of light filler.

12. Wet mortar, characterized in that it was obtained after mixing a dry mortar composition according to any one of claims 1 to 11 with water and in that it has: - a paste density, measured according to standard NF EN 1015-6, of between 700 g / L and 1,400 g / L, preferably between 1,000 g / L and 1,200 g / L, - a volumetric air content, expressed in relation to the total volume of said wet mortar, of between 30% and 70%, preferably between 40% and 55%.

13. A method for preparing a wet mortar according to claim 12, characterized in that a dry mortar composition according to any one of claims 1 to 11 is mixed with water using an electric mixer with a rotation speed of between 400 rpm and 1,100 rpm, preferably between 600 rpm and 900 rpm, for a period of between 1 minute and 5 minutes, preferably between 2 minutes and 3 minutes.

14. A method for fixing tiles to a substrate, characterized in that it comprises at least the following steps: - a dry adhesive mortar composition according to any one of claims 1 to 11 is mixed with water to obtain a wet adhesive mortar according to claim 12; - said wet adhesive mortar is applied to the substrate and / or to the tiles; - the tiles are applied to said substrate.

15. Method of fixing a tile to a support according to claim 14, characterized in that the mixture is prepared with an electric mixer whose rotation speed is between 400 rpm and 1100 rpm, preferably between 600 rpm and 900 rpm, for a period of between 1 minute and 5 minutes, preferably between 2 minutes and 3 minutes.