Mortar screed composition, screed, building and method based on such a composition

Abstract

The invention relates to a screed mortar composition comprising, for 260 to 280 l, preferably 270 l, of composition: - from 230 to 250 l, preferably from 235 to 245 l, of silico-calcareous sand; - from 40 to 60 kg, preferably from 45 to 50 kg, of clinker-poor decarbonated cement, comprising metakaolins; - from 300 to 380 ml, preferably from 310 to 330 ml, of binder-type adjuvant; - water in an amount sufficient for 260 to 280 l, preferably 270 l, of composition, these components being mixed and the screed mortar composition being solidified so as to obtain a mortar screed. The resulting mortar screed has a peel strength of between 0.8 and 1.5 MPa, preferably of 1 MPa. The invention makes it possible to produce a low-carbon mortar screed.

Description

Composition of mortar screed, screed, building and process based on such a composition

[0001] The invention relates to the field of cement compositions for screeds based on cement mortar.

[0002] In this field, the cement generally used is Portland cement CEM II 32.5R. This cement is clinker-based (50-70%), which makes it very energy-intensive. This represents a major drawback from an environmental perspective.

[0003] Besides clinker, this cement includes about 20% slag from the iron industry, which is also very energy-intensive.

[0004] Thus, mortar screeds using Portland cement imply a negative carbon footprint that requires improvements.

[0005] Other parts of buildings or other screeds are based on concrete containing gravel, which is not the case for the mortar screeds that are the subject of this invention. The gravel greatly impacts this type of composition from a physical / mechanical standpoint, which means that for a mortar screed, the ingredients and their proportions must be carefully adjusted to achieve the desired physical / mechanical properties.

[0006] Solutions have been proposed to provide more environmentally friendly cement (known as low-carbon or decarbonized cement), such as H-UKR cement offered by HOFFMANN GREEN CEMENT TECHNOLOGIES. This is a cold-mixed cement, which reduces energy consumption and makes it environmentally friendly.

[0007] Besides cement, the manufacture of screed mortar requires additional elements, including sands, setting and drying accelerators (no gravel unlike concrete screeds); as well as water in specific proportions.

[0008] Unfortunately, conventional decarbonized cement has different physical / mechanical properties than Portland cement, which means that very specific proportions of the different components must be used.

[0009] Furthermore, the compositions generally include anti-surface cracking polypropylene fibers for the mechanical strength of the screed.

[0010] Some additives are offered but are indicated for Portland cements, not for decarbonized cements.

[0011] Furthermore, in the case of mortar screeds, it is important that the resulting screed has a pull-out strength between 0.5 and 1.5 MPa (for P4S type premises, a special case), usually 0.6 MPa for the installation of bonded floor coverings, preferably around 0.8 MPa; and a setting time of 1 cm every 8 days. This mechanical stress is important to facilitate the adhesion of the floor covering laid on the mortar screed (tile adhesive or other). Indeed, with a pull-out strength of less than 0.5 MPa, the screed will not have sufficient surface cohesion to support a floor covering adhesive (such as tile or parquet) and will become porous. With a strength exceeding 1.5 MPa, the screed dries too quickly, which will cause cracking. It will then be necessary to repair, or even remove, the screed.

[0012] Thus, mortar screeds using decarbonized cement proposed in the prior art have a pull-out resistance of more than 1.5 MPa, which will generate the same problems.

[0013] These decarbonized cements require extensive refining of the ingredients and their mixing to achieve a mortar screed with the required physical / mechanical properties.

[0014] One objective of the invention is to remedy the defects of the prior art and to propose a screed mortar composition enabling the screed to be obtained with the required physical / mechanical properties including a pull-out resistance between 0.5 and 1.5MPa.

[0015] To achieve this objective, the invention proposes a screed mortar composition comprising, for 260 to 280L, preferably 270L of composition: - 230 to 250 L, preferably 235 to 245L of silico-calcareous sand; - 40 to 60 kg, preferably 45 to 50 kg of decarbonated cement including metakaolins; - 300 to 380 ml, preferably 310 to 330 ml of binder-type additive; - water in sufficient quantity for 260 to 280L, preferably 270L of composition, these components being mixed and the screed mortar composition being solidified so as to obtain a mortar screed.

[0016] More specifically, the said components are mixed and the screed mortar composition is solidified so as to obtain a mortar screed, so that the screed obtained has a pull-out resistance of between 0.5 and 1.5 MPa, preferably between 0.5 and 1.2 MPa, more preferably between 0.8 and 1 MPa.

[0017] The sand is preferably sand with a grain size of 0 / 5, preferably 0 / 4, i.e. grain sizes between 0 and 5 or 4 mm.

[0018] In particular, the resulting mortar screed has a pull-out resistance of between 0.5 and 1.5 MPa, preferably 1 MPa.

[0019] Advantageously, the composition according to the invention provides good physical / mechanical properties, acceptable elasticity, and is fully usable as a mortar screed. Furthermore, the adhesion of coatings is satisfactory with this composition.

[0020] With 250 ml of additives or less, the drying time is too long, the screed lacks mechanical strength and crumbles, requiring removal and re-layment. The binder helps the cement bond better to the sand without making the screed too rigid.

[0021] According to a preferred variant, the screed mortar composition includes: - 240 L of 0 / 4 grain size silico-calcareous sand; - 50 kg of decarbonated cement including metakaolins; - 320 ml of binder-type additive.

[0022] This allows for ideal physical / mechanical properties, and perfect adhesion of the coverings laid on the screed.

[0023] According to one variant, decarbonized cement is H-UKR cement. This cement is marketed by the company HOFFMANN GREEN CEMENT TECHNOLOGIES.

[0024] This allows the use of commercially available low-carbon cement so that the composition can be formulated quickly.

[0025] According to one variant, the adjuvant is Retanol Xtreme. TM or an adjuvant containing more than 80% of the components. Preferably, this should be an adjuvant from the Retanol Xtreme brand. TM .

[0026] This allows the use of a commercially available adjuvant so that the composition can be formulated quickly.

[0027] The invention further relates to a kit for producing at least one screed mortar composition according to the invention, comprising an electric mixing machine.

[0028] This allows for an even more environmentally friendly approach to the mortar screed application.

[0029] Another object of the invention relates to a mortar screed comprising a screed mortar composition according to the invention.

[0030] This allows for the creation of a low-carbon cleat.

[0031] The invention further relates to a building comprising a mortar screed which includes a screed mortar composition according to the invention.

[0032] This allows for the construction of a low-carbon building.

[0033] The invention also relates to a method for manufacturing a mortar screed, comprising a step of mixing the components of a screed mortar composition according to the invention, a step of applying the composition and a drying step.

[0034] The invention will be further detailed below, based on particular non-limiting embodiments.

[0035] The invention relates to a low carbon screed mortar composition, making it possible to offer a low carbon mortar screed comprising little or no clinker.

[0036] The invention relates to a wet-type mortar screed mixed on site and leveled on site by an operator.

[0037] The invention allows for a better carbon footprint than prior art solutions.

[0038] The mortar composition for the screeds of the invention is based on a low-clinker, decarbonated cement comprising metakaolins. This cement comprises less than 10% clinker, more particularly 0% clinker.

[0039] The mix design includes, for 260 to 280 L, preferably 270 L, 45 to 50 kg of this decarbonated cement. The ideal mix design includes 50 kg of decarbonated cement when using a 270 L tank (300 L total capacity). The preferred option is H-UKR cement from HOFFMANN GREEN CEMENT TECHNOLOGIES.

[0040] The mortar mix also includes sand, preferably silico-calcareous sand. Specifically, 235 to 245 liters of silico-calcareous sand are required for the tank. The ideal mix contains 240 liters of silico-calcareous sand.

[0041] Surprisingly, the inventor found that particle sizes between 0 and 4mm allow for a functional composition, whereas the prior art for screeds generally uses sand between 0.8 and 1.2mm. Thus, in the invention, the user has less need for filtration and less loss of sand with grains between 1.21 and 5mm in size.

[0042] The sand is preferably sand with a grain size of 0.4 mm. Advantageously, this allows for an optimal composition for screed applications within the scope of the invention. The sand is washed before use.

[0043] Furthermore, the mortar composition includes binder-type additives, preferably Retanol Xtreme. TM Specifically, there are 310 to 330 ml of a binder-type additive for the tank. The ideal composition includes 320 ml of a binder-type additive.

[0044] Commercially available additives are sold in 20L containers, for example. The recommended dosage is 5 to 6.5 ml / kg of cement. The invention proposes a preferred dosage between 4 and 7.5 ml / kg of cement. Advantageously, the invention requires less precision, meaning that a more approximate measuring / sampling tool can be used in the process, while still achieving a functional composition.

[0045] The aforementioned components are mixed with water in sufficient quantity to create 270 liters of the mixture in the tank. The screed is then transported to the installation sites and floors for application before it hardens. Surprisingly, the resulting screed has a pull-out resistance between 0.5 and 1.2 MPa, preferably 0.8 MPa. These characteristics are linked to the specific formulation and mixing proportions used, including the quantities of sand and water.

[0046] Prior art screeds generally require compressive strengths above 15 MPa and adhesion strengths of 2 MPa. Consequently, these prior art screeds dry too quickly, leading to cracking that is not present with the compositions of the invention at the same stage. This cracking subsequently necessitates repairs to the prior art screed, or even its removal in some cases.

[0047] The screed is made using an electric conveying device for the mix. The invention further relates to a kit for producing at least one screed mortar mix as described above, comprising an electric mixing and conveying machine. Specifically, it consists of an electric mixer-pump, eliminating the need for non-road diesel fuel, as used in the prior art. This machine mixes the mortar and pressurizes it with a compressor to deliver it to the different floors for application before smoothing.

[0048] The electric machine allows for an even more environmentally friendly process.

[0049] The resulting mortar screed is another aspect of the invention, as it is a low-carbon screed. The same applies to the building constructed from it.

[0050] The invention further relates to a method for manufacturing a mortar screed based on the composition described above.

[0051] The process includes a step of mixing the components of said screed mortar composition, in particular with an electric mixing machine.

[0052] The process further includes an application step of said composition, followed by a drying step.

Claims

Composition of screed mortar comprising, for 260 to 280L, preferably 270L of composition: - 230 to 250 L, preferably 235 to 245L of silico-calcareous sand; - 40 to 60 kg, preferably 45 to 50 kg of decarbonated cement including metakaolins; - 300 to 380 ml, preferably 310 to 330 ml of binder-type additive; - water in sufficient quantity for 260 to 280L, preferably 270L of composition, these components being mixed and the screed mortar composition being solidified so as to obtain a mortar screed. Screed mortar composition according to the preceding claim, characterized in that said components are mixed and the screed mortar composition is solidified so as to obtain a mortar screed, such that the screed obtained has a pull-out resistance of between 0.5 and 1.5 MPa, preferably between 0.5 and 1.2 MPa, more preferably between 0.8 and 1 MPa. Composition of screed mortar according to the preceding claim, characterized in that said pull-out resistance is 0.8 MPa. Composition of screed mortar according to one of the preceding claims, characterized in that said sand has a particle size of 0 / 5, preferably 0 / 4. Composition of screed mortar according to the preceding claim, characterized in that said sand has a grain size of 0.4 mm. Composition of screed mortar according to one of the preceding claims, characterized in that it comprises: - 240 L of silico-calcareous sand of granulometry 0 / 4; - 50 kg of decarbonated cement comprising metakaolins; - 320 ml of binder-type additive. Composition of screed mortar according to any one of the preceding claims, characterized in that the decarbonized cement is an H-UKR cement. A screed mortar composition according to any one of the preceding claims, characterized in that the additive is Retanol Xtreme. TM . Kit for producing at least one screed mortar composition according to one of the preceding claims, comprising an electric mixing machine. A mortar screed comprising a screed mortar composition according to any one of claims 1 to 8. Building comprising a mortar screed comprising a screed mortar composition according to any one of claims 1 to 8. Method for manufacturing a mortar screed, comprising a step of mixing the components of a screed mortar composition according to any one of claims 1 to 8, a step of applying the composition and a drying step.