EP2688856A1

EP2688856A1 - Dry cement composition for preparing a wet coating formulation consisting of non-efflorescent mortar or cement

Info

Publication number: EP2688856A1
Application number: EP12710297.8A
Authority: EP
Inventors: Anne Daubresse; Audrey Bellet; Jean Ambroise; Michel CHABANNET
Original assignee: ParexGroup SAS
Current assignee: ParexGroup SAS
Priority date: 2011-03-24
Filing date: 2012-03-26
Publication date: 2014-01-29
Also published as: FR2973024A1; WO2012127066A1; FR2973024B1

Abstract

The invention relates to a dry cement composition for preparing a wet coating formulation consisting of mortar or concrete, enabling, in particular, the creation of thick non-efflorescent inorganic coatings without adversely affecting the other properties required for the corresponding wet formulation, namely handiness, workability, pumpability, rheology, ease of mixing and application, as well as ease of cleaning tools, and without adversely affecting the properties of the hardened objects obtained from said wet formulation, namely surface protection/sealing, hardness, resistance to cracks, durability, and fire resistance. The composition according to the invention includes (a) CAC and/or CSA and (c) anhydrite, and at least one of the following compositions: (b) an organic binder; (d) a setting retarder; (e) a setting accelerator; (f) a water-retaining agent; (g) a filler; (h) a waterproofing agent; (i) a coloring agent; (j) a photocatalytic additive; (k) fibers; and (m) an antifoaming agent. Said composition is (almost entirely) free of Portland cement, and the ratio of the composition (a)/(c) is between 90/10 and 99.99/0.01. The invention also relates to the wet formulation obtained by mixing the cement composition with water, to the methods for preparing the cement composition and the corresponding wet formulation, to the coating obtained by applying the wet formulation, to the application thereof, and to the coated substrates.

Description

DRY CEMENTITIOUS COMPOSITION FOR PREPARING WET FORMULATION OF COATING, MORTAR OR CONCRETE WITHOUT

EFFLORESCENCE Technical field

The technical field of the invention is that of cementitious powder compositions intended for the preparation of wet formulations of mortars or concretes for the building.

More specifically, the invention relates to a dry cementitious composition for the preparation of a wet formulation of coatings, mortars or concretes allowing the realization of coatings by projection or spreading on a concrete building surface, or coated with a coated or an external thermal insulation system (ITE).

The coatings considered may be wall coverings, preferably exterior. The present invention aims in particular thick mineral coatings (RME), or even thin mineral coatings (RMM), but also a wide range of mineral decorative coatings, mineral paints with thick coatings.

These coatings are intended to participate in the decoration, protection, and waterproofing of buildings and more particularly to be applied as a decorative layer on masonry-coated substrates, as a coating on an ITE system or as a coating on an ITE system. coated on concrete.

Technological background

Efflorescence is a well-known phenomenon that affects cementitious coatings, undermining their decorative appearance due to surface crystallization of insoluble calcium carbonate salts which thus form an undesirable whitish layer. These calcium carbonate salts also called calcites, have as precursor calcium oxides produced during the hydration of Portland cement and / or the presence of lime in the formulation. These calcium oxides are solubilized and then transported by water (from the mixing water, upwellings in the support or water inlets by precipitation), from the interior of the coating to the surface and form on it white crystalline deposits after evaporation of the water. Calcium carbonates are converted by reaction with ambient carbon dioxide.

Since CaOH ₂ is the cause of efflorescence, it has been proposed to use weakly alkaline binders such as calcium sulpho aluminate cements (CSA) or aluminum aluminate cements. Calcium (CAC) that contain or produce little or no CaOH ₂ . Since part of the salts causing efflorescence can come from the concrete substrate on which a coating or a mortar is applied, it has been envisaged to apply to the substrate a polymer film forming a barrier to these salts between the substrate and the substrate. outer coating layer.

Moreover, the decorative mineral coatings are more particularly subject to a more or less rapid aesthetic aging depending on their exposure, either by particulate air pollution or by proliferation of microorganisms.

GB2360769-A discloses cementing compositions that limit the efflorescence phenomenon by allowing the reaction of CaOH ₂ with CSA and calcium sulfate (gypsum) to form ettringite, as taught in GB2099808-B. Having found that mineral monosulfate and hydrated alumina are co-products of ettringite and that these co-products are detrimental to the physical properties of cement, GB2360769-A proposes to associate Portland cement (CPA) with CAC (SECAR®51) calcium sulfate (gypsum) and reactive silica, to overcome this disadvantage. The CAC / gypsum weight ratios generally disclosed in GB2360769-A are from 0.8 to 30 and those referred to in the examples are 0.9; 3.5; 5 and 8.6.

JP60-251162-A discloses a mortar composition comprising white cement, white CAC, gypsum hemihydrate, a polymer dispersion and siliceous sand. The CAC / gypsum ratios disclosed in JP60-251162-A are 1.5; 2.25 and 2.

EP1858822-B1 relates to a non-efflorescence, reactive silica-free cementitious mortar composition comprising from 1 to 10% by weight of Portland CPA cement, from 1 to 30% by weight of CAC and from 1 to 15% by weight of calcium sulphate. The CAC / calcium sulfate ratios according to this document are between 0.067 and 30. In the examples, the CAC / gypsum ratio is 3.

None of the formulas of cement compositions above mentioned, gives rise to an acceptable compromise between the reduction of efflorescence and the preservation of mechanical properties including durability, cohesion (hardness-resistance to cracking) over time.

It is also important that the gain in terms of reduction of efflorescence does not occur at the expense of the other properties required for the achievements obtained from wet formulations coated, mortars, concretes, resulting from dry cement compositions. The properties of the wet formulation are considered here: maneuverability, workability, pumpability, rheology, ease of mixing and application as well as cleaning of tools and the properties of hardened objects obtained from this wet formulation: protection / waterproofing, thermal and acoustic insulation, hardness, crack resistance, durability. Technical problem - Objectives of the invention

In this context, the technical problem at source in the present invention is to satisfy at least one of the objectives set out below:

- Provide a dry cementitious composition stable in storage in dry form and leading after mixing and hardening to coatings not subject to efflorescence.

- Provide a dry cementitious composition, after mixing with water and application or shaping and curing to produce coatings not subject to efflorescence and with stable properties in terms of durability, hardness, cohesion, protection / waterproofing , resistance to cracking.

- Provide a dry cementitious composition leading, after mixing with water, to wet formulations (pastes, coatings, mortars, concretes) that are easily castable and easy to implement, with an acceptable water retention during mixing, presenting a consistency and a paste viscosity allowing pumping by a machine, a pumping ability, a workability long enough to achieve mixing and application including coatings, while remaining economical, and stable after mixing.

- Provide a dry cementitious composition leading, after mixing with water, to wet formulations (pastes, coatings, mortars, concretes), from which can be made coatings with photocatalytic performance to degrade, by UV exposure organic soils likely to proliferate on these coatings.

- Provide a wet formulation, obtained by mixing with water of the cementitious composition referred to in the above objectives, said wet formulation having the above-mentioned properties.

- Provide processes for the preparation of the cementitious composition and the corresponding wet formulation, which are easy to implement and economical.

- Provide an external building covering, for example a thick mineral coating RME, obtained by application of the wet formulation mentioned in the objectives mentioned above (coatings, mortars, cements) and endowed with good long-term mechanical performance (hardness, resistance to cracking, durability, cohesion) and good performance of implementation, while having, in the long term, optimal qualities in terms of decoration (absence of lime efflorescence and possibly limitation of fouling).

Brief description of the invention

The problem mentioned above is solved by the invention which proposes a dry cementitious composition having an optimized CAC / SS ratio.

From which it follows that the present invention relates, in a first aspect, a dry cementitious composition for the preparation of a wet formulation of plaster, mortar or concrete characterized,

■ in that it includes:

(a) a cementitious mineral hydraulic binder comprising calcium aluminate (CAC) and / or calcium sulpho aluminate (CSA) cement;

(c) a sulphate source (S S);

and at least one of the following components:

(b) an organic binder;

(d) a set retarder;

(e) a setting accelerator;

(f) a water retainer;

(g) a charge;

(h) a water repellent;

(i) a colorant;

(j) a photocatalytic oxide;

In that the ratio (a) / (c), [(a) and (c) being expressed in% by dry weight relative to the composition], is, in an increasing order of preference, between 80/20 and 99.99 / 0.01; 90/10 and 99.99 / 0.01; 85/15 and 99.99 / 0.01; 98/2 and 99.99 / 0.01.

Preferably, this composition comprises, in ascending order of preference, less than 2.7; 2.5; 2.0; 1.5; 1.0; 0.5% of portland cement (CPA), this percentage of CPA being expressed in% by weight on a dry basis with respect to the dry mass of the components (a); (vs) ; (b) and CPA.

According to one variant, the composition has a portland cement concentration, expressed in% by dry weight of the composition and in increasing order preferably, less than 5; 1; 5.10 ^-1 ; 10 ^-1 ; 5.10 ^-2 ; 10 ^-2 ; 10 ^-3 ; 10 ^-4 ; 10 ^-5 ; 10 ^-6 . In a preferred embodiment of the invention, the composition according to the invention comprises at least one organic binder (b) and has a ratio (a) / (c) of between 98/2 and 99.99 / 0, 01.

It should be emphasized that the composition according to the invention makes it possible to lead to hardened coatings having a very good resistance to blooming not only the primary efflorescences but also the secondary efflorescences.

The composition according to the invention gives access to wet formulations that are easily prepared, perfectly manageable, of suitable rheology and workability and, ultimately, to hardened, non-efflorescent coatings or solid objects having quite satisfactory mechanical properties. and stable over time.

The specifications are also satisfied with regard to the specifications of decoration, protection and waterproofing.

The cementitious composition according to the invention can be for example:

Embodiment M1: Thick Mineral Coating (RME) or Thin Mineral Coating (RMM);

• Embodiment M2: a mineral paint.

Moreover, the composition according to the invention makes it possible to lead to hardened coatings having good fire resistance. In fact, the hydration products of the CAC / sulphate mixtures in the ratios described by the patent are mainly calcium mono-sulphoaluminate, and ettringite.

The structure of the monosulfoaluminate (C3A, C $, H 12), the majority product of the hydration of the binder system according to the invention, contains 12 water molecules. The structure of ettringite (C3A, 3C $, H32) contains 32 molecules of water. Thanks to a large number of moles of water in their structure, monosulfoaluminate, ettringite and gypsite reduce the speed of fire propagation systems in which they are incorporated.

In embodiment M1, the composition comprises:

At least one filler (g) chosen from sand and / or aggregates; this load (g) possibly being supplemented by at least one filler (m);

• and at least one water retainer (f).

According to a remarkable embodiment of the invention, the filler (g) is chosen from the composition, or more preferably constituted by siliceous, calcareous, silico-calcareous sand and mixtures thereof.

In embodiment M2, the composition is characterized in that the filler (g) is chosen from among the mineral fillers, preferably among limestone or magnesium fillers. According to another of its aspects, the invention relates to a mineral hydraulic binder ingredient for a cementitious composition characterized in that it comprises a cement based on CAC and / or CSA and a source of sulfate (SS) and in that the ratio CAC and / or CSA / SS, [CAC and / or CSA and SS being expressed as% by dry weight relative to the composition], is, in an increasing order of preference, between 80/20 and 99.99 / 0.01; 90/10 and 99.99 / 0.01; 85/15 and 99.99 / 0.01; 98/2 and 99.99 / 0.01.

According to another of its aspects, the invention also relates to a wet formulation obtained by mixing the aforementioned composition with water.

In particular, the wet formulation (coating, mortar, concrete) according to the invention has good performance of implementation such as "workability" and rheological properties suitable for pumping. In addition, this coating has in particular on the mechanical level a suitable hardness and good resistance to cracking and durability.

According to another of its aspects, the invention provides a thick or thin mineral coating obtained from the aforementioned wet formulation.

According to another of its aspects, the invention relates to a process for the preparation of the abovementioned composition, said process consisting essentially in mixing the components of said composition or binder.

According to another of its aspects, the invention relates to a process for preparing the wet formulation as defined above, characterized in that it essentially consists in mixing with water a mixture ready for use. use comprising all or part of the binder (a) and / or (b) and the source (c) of sulphate SS, and optionally all or part of the other components, (d) to (m) for the RME or RMM, or d) to (j) for mineral paints, the cementitious composition according to the invention, the mixing time being preferably equal to 1 to 30 min, or even 3 to 10 min, the rest of the components then being gradually incorporated into the mix if this has not been done before.

According to another of its aspects, the invention relates to a method of application on a building surface or building construction of civil engineering using the wet formulation as referred to above. Definitions

The definitions given below as examples may be used to interpret this presentation:

• "polymer" denotes indifferently "homopolymer" and "copolymer";

• "particle size" corresponds to Dmax in dry sieving;

"Coating" refers more specifically to a mortar used in surface coating of a surface to protect, homogenize, decorate, etc .; "mortar" refers more specifically to a mixture of binder (organic hydraulic), fillers, sands (aggregates with a diameter <5mm), water, possibly additives and special additions;

The particle size of a "granulate" is greater than 1 mm, preferably less than or equal to 10 mm;

"Filler" denotes a powdery mortar charge, comprising, for example, siliceous, calcareous, silico-calcareous particles and / or particles of perlite or vermiculite, of particle size less than or equal to 200 μιη.

Detailed description of the invention

DRY CEMENTITIOUS COMPOSITION

The inventors have had the merit of putting a dry cementitious composition which, after hydration, leads to the predominant formation of calcium monosulfoaluminate preferentially to ettringite. However, the carbonation of calcium monosulfoaluminate preferentially leads to the formation of aluminum hydroxide (or gibbsite), without loss of cohesion of the composition, contrary to that the carbonation of ettringite preferentially leads to the formation of gypsum accompanied by a loss of cohesion and surface hardness.

Thus, the coatings obtained after mixing with water and hardening of this cementitious composition have a scratch resistance and improved durability.

Preferably, the dry cementitious composition according to the invention is characterized by a scratch resistance at the end of a carbonation in a test T2 defined below (in Newtons), greater than or equal to, in an increasing order of preferably 1, 2, 3, 4, 5 for example between 6 and 100 or 6 and 50.

According to another preferred feature of the invention, the dry cementitious composition according to the invention is characterized by a degradation of an organic UV dye according to a T7 test defined below (in% L degradation), greater than or equal to in ascending order preferably at 10%, 15%, 30% at 24 hours.

Weight data

In the embodiment M1 (RME-RMM) of the invention, the dry cementitious composition is characterized by:

(a): [80-99.99]; [90-99.99]; [98- 99.99]

(c): [0.01-20]; [0.01-10]; [0,01-2]

(b) organic binder: [0-10]; [0- 5]; [0- 3]

(d) setting retarder: [0.02-0.5]; [0.05-0.3]; [0,1-0,2] (e) setting accelerator: [0.005-0.05]; [0.01-0.03]

(f) water retent: [0.01-1]; [0.02-0.3]; [0.03-0.15]

(g) charge: [60-85]; [65-80]; [70-75]

(h) water-repellent: [0-2]; [0, 1- 1]; [0.2-0.5]

(i) colorant: [0-10]; [0- 5]; [0- 2]

(j) photocatalytic oxide _. : [0-10]; [0- 5]; [1- 3]

(k) fibers: [0- 5]; [0-2]; [0- 1]

(1) antifoam: [0-0.1]; [0-0.05]; [0.001-0.01]

(m) filler: [0-20]; [2-10]; [4-8]

In the embodiment M2 (mineral paint) of the invention, the dry cementitious composition is characterized by the following concentrations, expressed as% dry weight of the composition and in increasing order of preference:

(a) CAC and / or CSA [80- 99.99]; [90-99.99]; [98- 99.99]

(c) SS [QM _. - 20]; [aOl-10]; [OJU- 2]

(b) organic binder [0- 20]; [2- 15]; [4- 10]

(d) set retarder [0.05-1]; [0] 0.5; [0 2- 0 _^ 4]

(e) setting accelerator [0.01-0JJ; [0.02- 0.05]

(f) water retainer [0JU-2]; [0 _^ 05- 0J5]; [0 £ 5- 0 _]

(g) Go limestone [20_-70]; [40-60]; [30-50]

(h) water-repellent [0-3]; [0J_-2]; [0 _^ 2- 0 _^ 8]

(i) dye [0-15]; [0-10]; [0- 5]

Qualitative data

HYDRAULIC BINDER MINERAL (a)

Advantageously, the CAC contained in the binder (a):

Has an alumina concentration greater than or equal to, in% by weight and in increasing order of preference: 40:50; 60; preferably between 65 and 75;

· Is preferably selected from TERNAL® WHITE, TERNAL® RG, SECAR® 41, SECAR® 51, SECAR® 60, SECAR® 71, SECAR® 80, CEMENT FONDU®, and mixtures thereof.

The CAC can be totally or partially replaced by CSA sulphoaluminous cement:

• having a concentration (in% by weight) of yeelimite greater than or equal to, preferably ¥ 5-55;

And preferably comprising or more preferably constituted by the KTS Belitex.

ORGANIC BINDER (b)

Preferably, the organic binder (b) is a polymer, preferably a polymer resin, the monomers or comonomers of which are chosen from the group comprising, or better still consisting of:

vinyl esters, preferably vinyl acetate,

the (meth) acrylates,

- aromatic vinyls,

olefins, preferably ethylene, 1,3-butadiene, styrene,

vinyl halides, preferably vinyl chloride, - and their mixtures.

This polymer is incorporated in the composition in the form of an aqueous dispersion and / or in the form of a redispersible powder, preferably produced by atomization (for example VINNA-PAS®), acrylic resins, styrene-acrylic, vinyl acetate / ethylene (VINNA). -PAS®), vinyl acetate / versatate / ethylene, vinyl acetate / vinyl ester / ethylene terpolymers and mixtures thereof being particularly preferred.

SOURCE SULFATE SS (c)

Preferably, the sulphate source (SS) is chosen from sulphates, preferably from the group comprising or better still constituted by the following sulphates: gypsum, hemihydrate, anhydrite, lithium sulphate, potassium sulfate or sodium and mixtures thereof; anhydrite being preferred.

It should be noted that in the case where SS corresponds to lithium sulphate, the concentration of SS is preferably between 1.10 ^-3 % by weight and 1% by weight and even more preferably is of the order of 0.01%. in weight.

BUILDERS

The adjuvants (d) to (m) have the role of providing a regularity of the properties of the material and allow to fulfill the precise specifications specific to each application of the dry cementitious composition: mortar, plaster, ...

Setting retarders (d) and setting accelerators (e)

The set retarders (d) and the setting accelerators (e) are water-soluble products which modify the solubilities, the dissolution and hydration rates of the various constituents of the dry cementitious composition.

The set retarder (d) is an important component or constituent of the composition according to the invention. He is indeed one of those who act on the ettringite transformation process obtained after hydration of the mineral hydraulic cementitious binder (a). It has indeed appeared interesting in accordance with the invention to promote the formation of gibbsite from ettringite.

The choice of the retarder (d) but also the accelerator (e) influencing this process is therefore one of the remarkable features of the invention.

The setting retarder (d) is preferably chosen from tartaric acid and its salts, preferably the sodium or potassium salts, the citric acid and its salts, preferably the sodium salts (trisodium citrate) and their salts. mixtures.

The setting accelerator (e) is chosen from carbonates, preferably lithium or sodium, sulphates, preferably lithium, and mixtures thereof. Water repeater φ

The water retainer (f) has the property of preserving the mixing water before setting. The water is thus maintained in the plaster, mortar or concrete paste, which gives it a very good adhesion and good hydration. To a certain extent, it is less absorbed on the support, the release on the surface is limited and there is thus little evaporation.

The water retainer (f) is chosen from: polysaccharides, preferably cellulose ethers and mixtures thereof, and preferably from the group comprising methylcelluloses, methylhydroxypropylcelluloses, methylhydroxyethylcelluloses and mixtures thereof, or from among modified or unmodified guar ethers and their mixtures or the mixture of these different families.

Charge (g)

Embodiment M1 (RME-RMM): the filler is chosen from sands and / or aggregates, preferably from siliceous, calcareous and silico-calcareous sands and mixtures thereof.

The load (g) of the embodiment M 1 may optionally be completed by at least one filler of the type defined hereinbelow.

- Embodiment M2 (paints): the filler is a filler chosen from mineral fillers, preferably from calcareous fillers.

Hydrojugant (h)

The water-repellent (h) is chosen from fatty acids and their sodium, potassium or magnesium salts and their mixtures, preferably from oleic acid, stearic acid, and their magnesium or sodium salts.

Dye (i)

The dye (i) is chosen from iron, titanium and chromium oxides, polysulfurized sodium aluminosilicates and their mixtures, or organic dyes. Photochemical Oxyd (j)

This feature which consists in providing at least one photocatalytic additive, preferably at least one photocatalytic oxide or a photocatalytic oxide system (s), allows, after mixing (for example with water) of the dry composition, to produce coatings. self-cleaning vis-à-vis organic soils may proliferate on their surface. Generally, this photocatalysis is activated by UV.

This photocatalytic oxide may be chosen from the group comprising, or better still consisting of: titanium oxides TiO 2, preferably anatase crystallographic form, or anatase-rutile mixture, preferably with a specific surface area greater than, this specific surface area being expressed in m ² / g and listed below in increasing order of preference, ; 30 ; 50; and their mixtures;

The zinc oxides, ZnO, preferably having a specific surface area greater than 1 m ² / g, these zinc oxide being more preferably still chosen from those obtained by the so-called "direct" or "American"process;

and their mixtures. l ibres (k)

The fibers (k) comprise polyamide, polyacrylonitrile, polyacrylate, cellulose, polypropylene, polyvinyl alcohol, glass, sisal, jute, hemp or blends of these fibers. Anti-foam (s)

Anti-foams (k) are used to increase the cohesion of the coating by limiting the presence of air bubbles. They reduce the side effect of other additives or consequent mixing, resulting in air.

The antifoam (k) is chosen from polyether polyols, hydrocarbon molecules, hydrophobic esters or mixtures thereof.

Fiier s (m)

The filler (m) is for example chosen from calcareous or magnesium fillers

INGREDIENT-BINDER HYDRA ULICAL MINERAL

Another subject of the invention is a mineral hydraulic binder ingredient for a cementitious composition, characterized in that it comprises a cement based on CAC and / or CSA and a sulphate source (SS) and in that the CAC ratio and / or CSA / SS, in% by dry weight relative to the composition, is, in ascending order of preference, 80/20 and 100/0; 90/10 and 99.99 / 0.01; 85/15 and 99.99 / 0.01; 90/10 and 99.99 / 0.01; 98/2 and 99.99 / 0.01.

WET FORMULATION

According to another of its aspects, the invention relates to a wet formulation formed by a mixture of water and the dry cementitious composition defined above. In particular this wet formulation may be constituted by a coating applicable to a building surface to achieve a coating. It may be in particular a thick mineral coating RME or a mineral thin coating NMR.

Advantageously, this wet formulation is characterized in that its water content is expressed by a mixing ratio (ratio of the mass of water introduced to the mass of dry matter in percentage by weight), included in the following intervals, according to a increasing order of preference: [10 -100]. [10-50]. [15-25] for RME and RMM (Embodiment M1) and [20-200]. [30-120]. [35-80] for mineral paints (Embodiment M2).

COATINGS

The invention also relates to the cured products obtained from the aforementioned wet formulation and / or that obtained by the process defined below, namely in particular RME and RMM (embodiment M1) and mineral paints (embodiment M2 ).

These RME or RMM coatings, or mineral paints, preferably have at least one of the following properties:

Adhesion to concrete, coating or ITE (T6 test defined below) greater than or equal to 0.2 MPa and preferably greater than or equal to 0.3 MPa or cohesive in the case of a fracture in the support on ITE.

• Resistance to scratching, (test T3 defined below) after carbonation T2 defined below in a test, greater than or equal to 1 N and preferably greater than or equal to 2 N and without loss at the end of the tests of T2 carbonation.

• Resistance to primary and secondary efflorescence: at the end of the Tl test defined below and after drying of the coating, the latter must not present discoloration or salt deposition.

• Photo-catalytic performance with degradation of organic pigment, a degradation of L at 24 hours greater than or equal to, in% and in increasing order of preference, 1; 5; 15; in a T7 test defined below.

These coatings, for example inorganic paints, preferably have at least one of the following properties:

• Resistance to primary and secondary efflorescence: after the Tl test defined below and after drying of the paint, the latter must not present discoloration or salt deposition.

• Brush resistance of the paint to the abrasion test (T5 test defined below): The resistance is, on the one hand, advantageously greater than or equal to 50 cycles, before accelerated aging, and, secondly, advantageously less than or equal to this value, after aging T2;

• Photo-catalytic performance with degradation of organic pigment, a degradation of L at 24 hours greater than or equal to, in% and in increasing order of preference, 1; 5; 15; in a T7 test defined infira.

The invention also relates to the combinations of components (a) to (m) which may be provided separately to reconstitute at the moment of use the aforementioned dry cementitious composition.

In particular, they may be ready-to-use mixtures comprising either a monocomponent with all the necessary components (a) to (k), or a multi-component, for example a bi-component comprising, on the one hand, a part of the components (a) to (k) referred to above and secondly, the other part of the components (a) to (k) referred to above. PROCESSES

The invention also relates to the processes for preparing the aforementioned dry cementitious composition, the wet formulation defined above and the method of application on a building surface or construction of building or civil engineering work by means of the wet formulation according to the invention.

These methods are easy to implement by building practitioners.

As regards the mixing of the water with the dry cement composition, it may be a batch mixing in which is mixed in the tank of a machine to spray water to a mixture ready to the use comprising all or part of the components (a) to (k). The mixing time is preferably 1 to 30 minutes, or even 3 to 10 minutes. Some of the components can be incorporated gradually.

APPLICATION

Another object of the invention is the application by projection on a building surface preferably on a wall of the wet formulation defined above. These may be new or renovated buildings.

SUPPORTS

The invention also relates to the supports (concrete, coating, ITE system) coated with the cured wet formulation according to the invention. EXAMPLES

- 1 - Materials _. (a) Mineral Hydraulic Binder:

1. TERNAL ® WHITE, binder obtained by sintering consisting mainly of CA, CA ₂ and secondarily of Ci ₂ A ₇ , Aa. Alumina content> 68%, CaO content <31%), surface area blain> 3700 cm ² / g. Supplier: Kerneos. Production site: Le Teil (Fr) or West Thurrock (GB).

2. SECAR 71 ®, binder obtained by sintering consisting mainly of CA, CA ₂ and secondarily of Ci ₂ A ₇ , Aa. Supplier: Kerneos. Production site: Le Teil (Fr) or West Thurrock (GB).

(b) Organic binder:

1. Resin-re-dispersible resin Vinnapas 5535T from the company WACKER.

Ethylene vinyl acetate copolymer. 98-100% solid), ash: 8-13% polyvinyl alcohol protective colloid, max. 4% rejection at 400 μπι, predominant particle size 0.5-8 μπι, film formation temperature 4 ° C.

2. Axilat UP600B re-dispersible water resin from FLEXION.

Copolymer of vinyl acetate, vinyl versatate and maleic ester.

Solid material 99-100%, 10-14% ash, average particle size 80 μπι approximately, minimum film formation temperature 6 ° C.

(c) Source of SS sulphate:

1. micronized anhydrite MICRO A. S03 content 50% +/- 1%, CaO content 38.7%), specific surface area 5300 cm ² / g +/- 100. Supplier: Maxit. Production site: Faulquemont (Fr).

2. Anhydrite Francis Flower. Content of calcium sulphate> 94%>. Supplier: Francis Flower.

(d) Retarder:

Trisodium citrate dihydrate CeH ₅ Na30 ₇ . 2 H ₂ 0 reference F6000 of the company

Univar. Title 99% - 100.5%. Granulometry: maximum 15% passing to 200 μιη and 10% maximum rejection at 630 μηι.

(e) Take Accelerator:

1. Fine grade RODACHEM light grade lithium carbonate. Li ₂ content C0 ₃ > 99%.

Density 2.049 g / cm ³ , average particle size 66 μπι.

2. Lithium carbonate grade CHEMETALL technical grade. Li ₂ content C0 ₃ > 99%. Density 2.1 1 g / cm ³ , granulometry 47% rejection at 420 μπι and 17% passing at 74 μηι. (f) Water repeater:

Methyl hydroxyethyl cellulose cellulose ether of brookfield viscosity 20000-270000 mPa.s (2% suspension / 20 ° C). WALOCELL MKW 20 000 PP01 from the company DOW.

(g) Charge:

- Procedure Ml: siliceous, calcareous or silico-calcareous sands and aggregates and possibly limestone filler.

Procedure M2: Filler limestone.

(h) Water-repellent:

1 - Sodium oleate of the company PETER GREVEN. Sieve refusal 800μιη <15%.

2 - magnesium stearate of the company METALEST.

(i) Colorant: Iron Oxide

(j) photocatalytic additive:

1 - "ZnO Neige®" from the company UMICORE®, obtained by direct process or so-called "American" process, with a ZnO content greater than 99.4%, a specific surface area of 1 to 3 m ² / g,

2 - MILLENIUM® PC 105 from CRISTAL GLOBAL®, with a specific surface area of 80 to 105 m ² / g, TiO ² concentration> 97%, mixed anatase / rutile crystallographic form.

(k) Fibers:

Polyacrylonitrile fibers of average length 0.8 mm. Reference FPAC 243 of the company STW.

(I) Anti-foam:

Powder based on a mixture of hyrophobic esters. Granulometry 99% <600 μηι. Reference PERAMIN DEFOAM 50 PE of the company PERAMIN.

-2- Procedure _. ;

* 2 kg of powder comprising the binder, the structuring filler, the adjuvants are prepared and mixed for 2 minutes on a laboratory mixer Guedu (model 4.5 NO) of useful capacity 3.5 liters at a speed between 545 and 610 revolutions / minute.

* The 2Kg of powder obtained is mixed on Perrier laboratory mixer: 30 seconds at a speed of 120 revolutions / minute and then 1 minute at a speed of 60 revolutions / minute. -3 - _. Measure, of _. properties _.. :

Tl: Resistance to primary and secondary efflorescence: • "Primary efflorescence" means the efflorescence occurring within hours after the material has been used (24 to 48 hours) while the material is saturated with water.

• "Secondary efflorescence" means efflorescence occurring after hardening and exposure of the material to liquid water (rain, runoff, capillary rise).

Coatings are applied to the associated substrate (concrete, coating or thermal insulation system from the outside). The models are subjected to a drop-of-water test 6 hours after application of the coating (primary efflorescence tests) and 28 days after hardening (secondary efflorescence tests). The models are inclined at 45 ° and a flow of distilled water flows on the model between 30 and 60 minutes. The drop height of the water is about 23 cm and the flow rate is 9 to 12 ml / minute.

At the end of the test and after drying, the appearance of the coating is observed. The latter must not present any discoloration or salt deposit.

T2: Carbonation resistance test:

The 28-day hardened plaster samples (model of pure paste without the sands or complete formulas) are placed in a chamber fed with a gaseous mixture consisting of 40% nitrogen and 60% CO 2 (in moles). The hygrometry is controlled and maintained above 80%. The gas flow rate is maintained by daily injection of a few liters of the mixture. The samples are placed in such a way that the gas mixture can circulate well. The mortar or paint formulations are rinsed weekly under demineralized water to simulate the rinsing effects of an external rain (about 300g / m ² demineralised water), the pure pasta is only preserved without rinsing. The test is maintained at least 28 days or 3 months. The evolution of the hardness of the coating at different times and the stability of the hydrates formed on pure pulp by ATD are measured.

T3: Resistance to scratching

The hardness of the coating is determined using a sclerometer by measuring the resistance to scratch penetration using a 1 mm diameter tungsten carbide needle. The test will be done on the hardened coating at 28 days and after accelerated carbonation test. T4: Accelerated aging test on LTE system:

The aesthetic and mechanical durability (resistance to cracking and adhesion) is evaluated on a complete wall, the coating being applied as a decorative layer of a thermal insulation system from the outside. The aging cycle is carried out according to ETAG guide No. 004.

T5: Abrasion test on paints:

The abrasion test is carried out according to ASTM D 2486 according to method A. The paint is in our case applied to a fibro-cement substrate without prior application of primer to a thickness of about 0.25 mm. The evaluation is made after 28 days of drying and after 28 days of drying + 28 days of carbonation following the T2 test. We note after how many cycles the support begins to be visible.

T7: Degradation test of an organic pigment:

The photocatalytic performance is evaluated by an organic pigment degradation test, rhodamine, deposited on the coating cured by U.V exposure, with colorimeter monitoring in the system L a b.

Operating mode:

A 10x20 cm model is produced on which a plaster sample is applied in the form of a coating. This coating is allowed to harden.

A first colorimetric measurement is made on a model of dimension 10x20 cm on which a sample of coating is applied as a coating in its initial state,

The model is covered as evenly as possible with rhodamine B spray. It is then kept at least 16 hours in air-conditioned room. A colorimetric measurement is made at to.

The model of approximately 10x20 cm dimension is placed in a closed box, 33 cm from a 365 nm 24 watt UV lamp.

A colorimetric follow-up is carried out at different dates, up to 24h.

The degradation of L is expressed as a percentage according to the following calculation: Initial Delta = (initial L - L tO)

Delta rate relative to t0 = (L tx-L tO)

Degradation L (%) at tx = (Delta tx with respect to tO * 100) / initial Delta. -5- Conclusions:

These examples show that the compositions according to the invention have a very good resistance to primary and secondary efflorescence and a scratch resistance which is not degraded after accelerated aging. The photocatalytic properties of the treated coatings are also demonstrated.

Claims

1. Dry cementitious composition for the preparation of a wet formulation of plaster, mortar or concrete characterized,

^■ in that it includes:

(c) a sulphate source (S S);

and at least one of the following components:

(b) an organic binder;

(d) a set retarder;

(e) a setting accelerator;

(f) a water retainer;

(g) a charge;

(h) a water repellent;

(i) a colorant;

(j) a photocatalytic oxide;

^■ in that the ratio (a) / (c) [(a) and (c) being expressed as% by dry weight relative to the composition] is, according to an increasing order of preference, between 80/20 and

99.99 / 0.01; 90/10 and 99.99 / 0.01; 85/15 and 99.99 / 0.01; 98/2 and 99.99 / 0.01.

2. Composition according to claim 1 characterized in that it comprises, in increasing order of preference, less than 2.7; 2.5; 2.0; 1.5; 1.0; 0.5% of portland cement (CPA), this percentage of CPA being expressed in% by weight on a dry basis with respect to the dry mass of the components (a); (vs) ; (b) and CPA.

3. Composition according to claim 1 characterized in that it has a Portland cement concentration, expressed in% by dry weight of the composition and in increasing order preferably less than 5; 1; 5.10 ^-1 ; 10 ^-1 ; 5.10 ^-2 ; 10 ^-2 ; 10 ^-3 ; 10 ^-4 ; 10 ^-5 ; 10 ^-6 .

4. Composition according to claim 1 characterized in that it comprises at least one organic binder (b) and in that the ratio (a) / (c) is between 98/2 and 99.99 / 0.01.

5. Composition according to at least one of the preceding claims characterized in that it is a thick mineral coating (RME) or Thin (RMM), in that it comprises at least one filler (g) selected from sands and / or aggregates; this charge (g) being optionally supplemented by at least one filler (m), and in that it further comprises at least one water retainer (f).

6. Composition according to at least one of the preceding claims characterized in that it is a mineral paint and in that it comprises at least one filler (g) selected from mineral fillers preferably from limestone or magnesium fillers.

7. Composition according to Claim 5, characterized by the following concentrations, expressed in% by dry weight of the composition and in increasing order of preference:

(a): [80-99.99]; [90-99.99]; [98- 99.99]

(c): [0.01-20]; [0.01-10]; [0,01-2]

(b) organic binder: [0-10]; [0- 5]; [0- 3]

(d) setting retarder: [0.02-0.5]; [0.05-0.3]; [0,1-0,2]

(e) setting accelerator: [0.005-0.05]; [0.01-0.03]

(f) water retent: [0.01-1]; [0.02-0.3]; [0.03-0.15]

(g) charge: [60-85]; [65-80]; [70-75]

(h) water-repellent: [0-2]; [0, 1- 1]; [0.2-0.5]

(i) colorant: [0-10]; [0- 5]; [0- 2]

(j) photocatalytic oxide: [0-10]; [0- 5]; [1- 3]

(k) fibers: [0- 5]; [0-2]; [0- 1]

(1) antifoam: [0-0.1]; [0-0.05]; [0.001-0.01]

(m) filler: [0-20]; [2-10]; [4-8]

8. Composition according to Claim 6, characterized by the following concentrations, expressed as% dry weight of the composition and in increasing order of preference:

(a) CAC and / or CSA: [80-99.99]; [90-99.99]; [98- 99.99]

(c) SS: [0.01-20]; [0.01-10]; [0,01-2]

(b) organic binder: [0-20]; [2- 15]; [4- 10]

(d) set retarder: [0.05-1]; [0.1-0.5]; [0.2-0.4]

(e) setting accelerator: [0.01-0.1]; [0.02-0.05]

(f) water retainer: [0.01-2]; [0.05-0.5]; [0.05-0.3]

(g) calcareous filler: [20-70]; [40-60]; [30-50]

(h) water-repellent: [0-3]; [0, 1-2]; [0.2-0.8]

(i) colorant: [0-15]; [0-10]; [0- 5]

(j) photocatalytic oxide: [0-10]; [0- 5]; [1- 3]

9. Composition according to at least one of the preceding claims, characterized in that the CAC contained in the binder (a) has a concentration of alumina greater than or equal to, in% by weight and in ascending order preferably: 40%; 50%; 60%.

10. Composition according to at least one of the preceding claims, characterized in that the sulphate source (SS) is chosen from sulphates, preferably from the group comprising, or better still consisting of: gypsum, hemihydrate, anhydrite, lithium, potassium or sodium sulphate and mixtures thereof; anhydrite being preferred.

Composition according to at least one of the preceding claims having at least one of the following characteristics:

The organic binder (b) is a polymer, preferably a polymer resin, the monomers or comonomers of which are chosen from the group comprising, or better still consisting of:

vinyl esters, preferably vinyl acetate,

the (meth) acrylates,

- aromatic vinyls,

olefins, preferably ethylene, 1,3-butadiene, styrene,

vinyl halides, preferably vinyl chloride,

- and their mixtures;

this polymer being incorporated into the composition in the form of an aqueous dispersion and / or in the form of a redispersible powder, preferably produced by atomization, the acrylic, styrene-acrylic, vinyl acetate / ethylene, vinyl acetate / versatate / ethylene resins, the vinyl acetate / vinyl ester / ethylene terpolymers and mixtures thereof being particularly preferred;

The retarding agent (d) is preferably chosen from the group comprising, or better still consisting of: tartaric acid and its salts, preferably the sodium or potassium salts, the citric acid and its salts, preferably the sodium salts (trisodium citrate) and mixtures thereof;

The setting accelerator (e) is chosen from the group comprising, or better still consisting of: carbonates, preferably lithium or sodium, sulphates, preferably lithium, and mixtures thereof.

The water retainer (f) is chosen from the group comprising, or better still consisting of:

Polysaccharides, preferably cellulose ethers and mixtures thereof, and even more preferably in the subgroup comprising, or better still constituted by, the methylcelluloses, methylhydroxypropylcelluloses, methylhydroxyethylcelluloses and mixtures thereof;

^■ modified or unmodified guar ethers;

^■ or their mixtures;

the charge (g) is selected from the group comprising, or more preferably consisting of:

❖ Embodiment M1 (RME-RMM): sands and / or aggregates, preferably from siliceous, calcareous and silico-calcareous sands and mixtures thereof;

❖ Embodiment M2 (paints): the mineral fillers, preferably from calcareous or magnesium fillers.

the water-repellent (h) is chosen from the group comprising, or better still consisting of: fatty acids and their sodium, potassium or magnesium salts and their mixtures, preferably from oleic acid, stearic acid, and their magnesium or sodium salts;

the dye (i) is selected from the group consisting of, or more preferably consisting of, iron, titanium, chromium oxides, polysulfurized sodium aluminosilicates and mixtures thereof or organic dyes;

the photocatalytic oxide (j) is chosen from the group comprising, or better still consisting of:

Titanium oxides TiO 2, preferably of anatase crystallographic form, or mixed anatase-rutile, preferably with a specific surface area greater than, this specific surface area being expressed in m ² / g and listed below in increasing order of preference, 10; 30 ; 50;

Zinc oxides, ZnO, preferably having a specific surface area greater than 1 m ² / g, these zinc oxides being more preferably still chosen from those obtained by the so-called "direct" or "American"process;

• or their mixtures.

the fibers (k) are selected from the group consisting of, or more preferably consisting of: polyamide, polyacrylonitrile, polyacrylate, cellulose, polypropylene, polyvinyl alcohol, glass, sisal, jute, hemp or mixtures thereof;

the antifoam (1) is selected from the group comprising, or more preferably consisting of: polyether polyols, hydrocarbon molecules, hydrophobic esters or mixtures thereof;

the filler (m) is chosen from the group comprising, or better still constituted by, calcareous or magnesium fillers or their mixtures.

12. mineral hydraulic binder ingredient for a cementitious composition characterized in that it comprises a CAC-based cement and / or CSA and a sulphate source (SS) and in that the ratio CAC and / or CSA / SS, [CAC and / or CSA and SS being expressed in% by dry weight relative to the composition], is, in increasing order of preference, between 80/20 and 99.99 / 0.01; 90/10 and 99.99 / 0.01; 85/15 and 99.99 / 0.01; 98/2 and 99.99 / 0.01.

13. A process for the preparation of the composition according to at least one of claims 1 to 11 or the binder ingredient according to claim 12, characterized in that it consists essentially in mixing the components of said composition or of the ingredient-binding.

14. Process for the preparation of a wet formulation, characterized in that it consists essentially of mixing water with a ready-to-use mixture comprising all or part of the binder (a) and the source (c) of sulphate. SS composition according to at least one of claims 1 to 11 or the binder ingredient according to claim 12, and optionally all or part of the other components of the composition according to at least one of claims 1 to 11, the mixing time preferably being 1 to 30 min, or even 3 to 10 min, the rest of the components are then gradually incorporated into the mixture if this has not been done before.

15. Thick or thin mineral coating made from the wet formulation obtained by the process according to claim 14.

16. The coating of claim 15, characterized in that it has a concrete adhesion (Tl test) greater than or equal to 0.2 MPa, and preferably greater than or equal to

0.3 MPa.

17. A building or civil engineering work made at least in part with a wet formulation obtained by the process according to claim 14, said formulation curing after its application and shaping.

18. A method of application to a building or construction site construction or civil engineering, by means of the wet formulation obtained by the method of claim 14.