Natural pozzolan construction coating material and dry mix kit for preparing such a material

Abstract

The invention mainly relates to a construction coating material, which comprises a mixture of water and dry mix, said dry mix comprising a mixture of aerial lime and reactive mineral material exclusively consisting of natural volcanic pozzolan particles with a particle size of less than 2 millimeters having undergone no transformation. The invention further relates to a dry mix kit for preparing such a construction coating material in which said dry mix comprises a mixture of aerial lime and mineral material exclusively consisting of natural volcanic pozzolan particles with a particle size of less than 2 millimeters having undergone no transformation. The coating material of the invention can be used as plaster. finish plaster or paint.

Description

DESCRIPTION Title: Natural pozzolan-based building coating material and dry mass kit for preparing such a material TECHNICAL FIELD

[0001] The invention falls within the field of ecological building materials, and more particularly within the field of wall, floor and ceiling coverings for interior or exterior use.

[0002] The invention relates more particularly to the field of coatings and paints. PRIOR ART AND DISADVANTAGES OF PRIOR ART

[0003] Construction materials have a significant impact on the environment. For example, cement accounts for approximately 7% of global greenhouse gas emissions. Concrete, like mortar, is made from cement, which acts as a binder in the mixture and gives the finished material its mechanical strength.

[0004] In the more specific field of masonry mortars applied to finished walls, floors, or ceilings, then called plasters, it is known to mix a mineral material, most often sand, with cement and water. A plant-based material can optionally be added.

[0005] Depending on whether the mortar is for construction, covering, or finishing, the compositions differ according to the required properties, particularly in terms of mechanical strength and breathability. When a construction site requires the use of different mortars, several different mixes must be prepared, resulting in significant labor and material costs. The same applies to paints applied over plaster, which are known to have completely different formulations from mortar formulations. OBJECTIVE OF THE INVENTION

[0006] The invention aims to overcome the aforementioned drawbacks by providing a cement-free building coating material that offers the required mechanical strength when used as mortar. The invention also aims to provide a building coating material whose composition is suitable for all types of construction, covering, and finishing mortars, as well as for paints.

[0007] The invention also aims to provide a building coating material that is applied over a cement or base coat and before the application of a lime wash.

[0008] The invention also aims, in addition to the absence of cement use, to offer a completely ecological material.

[0009] The invention ultimately aims at a ready-to-use construction material kit for use on site by adding water for all the applications targeted. DESCRIPTION OF THE INVENTION

[0010] To this end, the invention relates to a construction coating material, which is essentially characterized in that it comprises a mixture of water and dry mass, said dry mass comprising a mixture of air lime and reactive mineral matter consisting exclusively of natural volcanic pozzolan particles of a grain size of less than 2 millimeters which have not undergone any transformation.

[0011] The material of the invention may also include the following optional characteristics considered individually or in all possible technical combinations: - said material is free of water-retaining agents - the said material is free of sand, clay and fixing agent. - said material consists of a mixture of air lime and reactive mineral matter consisting exclusively of natural volcanic pozzolana particles with a grain size of less than 2 millimeters which have not undergone any transformation, and optionally of a natural pigment or a mixture of natural pigments. - the particles of natural volcanic pozzolan have a grain size of less than 1 millimeter. - the particles of natural volcanic pozzolana have a particle size of less than 600 microns obtained by particle size cutting at 600 microns, preferably less than 500 microns obtained by particle size cutting at 500 microns, and more preferably less than 450 microns obtained by particle size cutting at 450 microns. - Natural volcanic pozzolana is red natural volcanic pozzolana. - the volume ratio between lime and pozzolana in the dry mass is greater than 1. - the volume ratio between lime and pozzolana in the dry mass is 1.5. - according to one variant, the volume ratio between lime and pozzolana in the dry mass is greater than 2 and less than 5, preferably between 3 and 4. - according to this variant, the material consists of a mixture of air lime and reactive mineral matter consisting exclusively of natural volcanic pozzolan particles with a grain size of less than 600 microns obtained by grain size cutting at 600 microns, preferably less than 500 microns, and more preferably less than 450 microns, and optionally of a natural pigment or a mixture of natural pigments. - according to this variant, the volume ratio between water and dry mass is between 1 and 1.5. - according to another variant intended for a coating application, the volume ratio between lime and pozzolan in the dry mass is greater than 1 and the volume ratio between the dry mass and water is between 2 and 3.5, preferably between 2.5 and 3.3, and in that the particle size of the pozzolan particles is less than 2 millimeters. - advantageously according to this variant for which the volume ratio between dry mass and water is between 2 and 3.5, preferably between 2.5 and 3.3, the pozzolan particles are from one or more granulometric cuts between 100 and 300 microns, preferably between 200 and 300 microns and more preferably between 200 and 250 microns. - according to another variant intended for paint application, the volume ratio between water and dry mass is between 0.8 and 1.4 and in that the average particle size of the pozzolan particles is less than 0.5 millimeters.

[0012] The invention also relates to a dry mass kit for preparing a construction coating material as previously defined, which is essentially characterized in that said dry mass comprises a mixture of aerial lime and mineral matter consisting exclusively of natural volcanic pozzolana particles with a grain size of less than 2 millimeters which have not undergone any transformation.

[0013] The kit of the invention may also include the following optional features, considered individually or in all possible technical combinations: the dry mass is free of sand, clay, binding agents, and water-retaining agents; the natural volcanic pozzolan particles have an average particle size of less than 1 millimeter; the natural volcanic pozzolan and red natural volcanic pozzolan are included; the volume ratio between lime or lime mixture and pozzolan in the dry mass is greater than 1, preferably 1.5.the dry mass consists of a mixture of air lime and reactive mineral matter consisting exclusively of natural volcanic pozzolan particles with a grain size of less than 600 microns by 600 micron grain size section, preferably less than 500 microns and more preferably less than 450 microns, having undergone no transformation, and optionally of a natural pigment or a mixture of natural pigments, and in that the volume ratio between lime and pozzolan in the dry mass is greater than 2 and less than 5, preferably between 3 and 4.

[0014] The invention also relates to the use of the material for application on a base coat and before the application of a lime wash.

[0015] The invention further relates to the use as a coating or as a finishing coating of the construction coating material of the invention for which the volume ratio between dry mass and water is between 2 and 3.5, preferably between 2.5 and 3.3, and the average particle size of the pozzolan particles is less than 2 millimeters.

[0016] The invention also relates to the use of the construction coating material of the invention as an interior or exterior wall paint, for which the The volume ratio between water and dry mass is between 0.8 and 1.4 and the average particle size of the pozzolan particles is less than 0.5 millimeters. PRESENTATION OF THE FIGURES

[0017] Other features and advantages of the invention will become clear from the description given below, which is by way of example and not limitation, with reference to the attached figure:

[0018] [Fig. 1] Figure 1 is a photograph of the surface of the construction coating material of the invention when the particle size of the natural pozzolan is between 100 and 300 microns, the surface being naturally covered with a varnish on which drops of water have been applied to characterize the hydrophobic properties of the varnish. DETAILED DESCRIPTION OF THE INVENTION

[0019] The invention relates mainly to a building coating material, which comprises a dry mass comprising a reactive mineral material consisting exclusively of natural volcanic pozzolan particles of a grain size less than 2 millimeters and air lime, mixed with water.

[0020] Reactive mineral matter is defined as mineral matter that directly contributes, either with or in reaction to air lime, to the mechanical properties of the coating material. For example, natural pigments that contribute to the aesthetic modification of the coating material are excluded from reactive mineral matter. Consequently, the invention covers a coating material that comprises, in addition to air lime and pozzolan particles, natural pigments, but contains no other reactive mineral matter besides natural pozzolan.

[0021] In this respect, the invention is particularly remarkable in that the material contains neither sand, nor clay, nor a fixing agent to prevent the rise of fine lime particles (powdery effect), nor a water-retaining agent. The material obviously contains no cement. Nor does it contain hydraulic lime. Optionally, and as previously mentioned, the mixture may contain natural pigments.

[0022] Thus, and preferably, the coating material of the invention consists of a mixture of air lime and reactive mineral matter made up exclusively of natural volcanic pozzolan particles with a grain size of less than 2 millimeters, which have not undergone any transformation, and optionally of a natural pigment or a mixture of natural pigments. Thus, the material of the invention consists either of water, air lime and particles of natural volcanic pozzolan of grain size less than 2 millimeters which have not undergone any transformation, or of water, air lime, natural volcanic pozzolan of grain size less than 2 millimeters and a pigment or a mixture of natural pigments.

[0023] As will be seen later, depending on the amount of water added and the particle size of the pozzolana particles, the material can be a construction mortar, a coating, a finishing mortar, or even paint.

[0024] The pozzolan used in the invention is exclusively natural pozzolan, namely volcanic aggregates with an alveolar structure. The natural pozzolan of the invention has not undergone any physicochemical transformation. Only mechanical modifications are applied to give it the desired particle size. For this purpose, and by way of example, the pozzolan is first crushed and then sieved. It is an essential element of the invention that the pozzolan be in the form of particles with an average particle size of less than 2 millimeters in order to give the resulting material, in particular the mortar, the required mechanical properties.

[0025] The pozzolan used may include, but is not limited to, red pozzolan from Réunion Island or grey pozzolan. Red pozzolan is preferred, as it produces a material with superior mechanical properties compared to materials made from grey pozzolan.

[0026] Pozzolanic materials are known to be siliceous or silico-aluminous materials that do not exhibit binding activity on their own but, in the presence of calcium hydroxide, form a material with binding properties. The pozzolanic activity index, ranging from 0.67 to 1, describes the rate of reaction between the pozzolanic material and the lime.

[0027] In the literature, the term pozzolana or pozzolanic material most often refers not to natural pozzolan, but to other materials exhibiting pozzolanic activity. For example, the term pozzolanic material, or even simply pozzolan, is used in the literature to refer to calcined pozzolan, shale, calcined shale, and ash. volcanic materials or clays such as crushed brick or metakaolin are excluded from the scope of the invention. The advantageous properties of a material made from natural pozzolan according to the invention, compared to a material made from crushed brick, will be shown later, highlighting the inferior properties of a material made from a clay compound.

[0028] According to the invention, the pozzolan particles have an average particle size of less than 2 millimeters, making it possible to produce all types of mortar, as well as paints, and to obtain the required mechanical properties. A particle size of less than 2 millimeters is defined as a particle size obtained by particle size analysis, for example, by sieving natural pozzolan using a sieve with a 2-millimeter opening diameter, resulting in pozzolan particles with a particle size of less than 2 millimeters. Thus, pozzolan particles obtained from a 2-millimeter particle size analysis have a particle size, or average diameter, of less than 2 millimeters. Preferably, the particle size is less than 1 millimeter, as this size has been observed to confer better mechanical properties, as will be discussed later.This particle size of less than 1 millimeter also allows the preparation of all types of mortars as well as paints.

[0029] For construction mortars, the particle size should preferably be less than 2 millimeters. For coating mortars, the particle size should preferably be less than 1 millimeter. For finishing mortars, the particle size should preferably be less than 0.5 millimeters. For paints, the particle size should preferably be less than 0.5 millimeters. Furthermore, the water content of the material relative to its dry mass will vary depending on whether the material is used as mortar or paint, as will be explained later.

[0030] With regard to lime, the man of the trade, aiming to avoid the use of cement and knowing pozzolanic materials, would have naturally been led to use hydraulic lime for its properties closer to those of cement than aerial lime, in order to give the finished material advantageous properties in terms of mechanical resistance.

[0031] However, it was unexpectedly noted in the context of the invention that air lime alone and in mixture with pozzolana, preferably in particular proportions defined in relation to natural pozzolana particles, This allowed the finished material to possess both mechanical properties similar to those obtained with hydraulic lime and advantageous breathability. Breathability is one of the essential criteria for mortars and plasters. Indeed, tests carried out with hydraulic lime instead of air lime resulted in impermeable surfaces, causing condensed water to run down the surface and leading to the growth of mold at the base. A mortar or plaster made according to the invention using only air lime, on the other hand, resulted in a surface capable of absorbing surrounding water and releasing it when the humidity level allows.This capacity is particularly important in tropical environments where ambient humidity is high and where the proliferation of fungi due to moisture accumulation on or at the base of walls is particularly noticeable. Conversely, and advantageously, the composition of the material of the invention allows for the creation of a coating material capable of absorbing water when the environment is humid and releasing the absorbed water when the ambient humidity permits.

[0032] Furthermore, tests carried out in connection with the invention have shown that the use of hydraulic lime, alone or mixed with air lime, results in a non-smooth surface, which is particularly disadvantageous when the material of the invention is used as a finishing plaster. In addition, when hydraulic lime is used mixed with natural pozzolan, the resulting material presents application difficulties for operators.

[0033] It was expected that the use of air lime would cause lime fines to rise to the surface of the finished material, particularly finishing plasters and paints, resulting in a white powdery appearance after drying. Unexpectedly, no such rise of fines was observed with the coating material of the invention. Most often, plasters or paints containing air lime also include additives, such as casein, which acts as a binder, or in other words, a glue for the fine lime particles, preventing them from rising to the surface. The presence of such additives with this function is excluded from the scope of the invention since, unexpectedly, the mixture of natural pozzolan and air lime does not cause lime fines to rise to the surface.

[0034] According to the invention, the volume ratio between lime and pozzolana in the dry mass is greater than 1, and can preferably be 1.5. These proportions allow the material to have good mechanical properties, as will be seen later.

[0035] According to an embodiment described in example 5, the volume ratio between lime and pozzolana in the dry mass is greater than 2 and less than 5, preferably between 3 and 4.

[0036] According to the invention, when the material of the invention is used as a coating, the volume ratio between the dry mass and the water is between 2 and 3.5, preferably between 2.5 and 3.3, in addition to the associated particle size distribution indicated above. These volume ratios make it possible to produce a mortar with an optimal consistency for application on walls, floors, or ceilings.

[0037] According to the invention, when the material of the invention is used as paint, the volume ratio between the dry mass and the water is between 0.8 and 1.4, in addition to the associated particle size indicated above. These volume ratios make it possible to produce a paint that is sufficiently fluid for application with a whitewash brush on walls, floors, or ceilings.

[0038] According to the invention, a surprising property has been observed in the material of the invention when used as a coating or paint, for a particle size of pozzolan obtained from one or more particle size fractions between 100 and 300 microns, and more particularly between 200 and 300 microns, more preferably between 200 and 250 microns. For this particle size range, and for a material in which the volume ratio between air lime and pozzolan in the dry mass is greater than 1, preferably 1.5, and the volume ratio between the dry mass and water is between 2 and 3.5, preferably 2.5 in this case, a transparent and hydrophobic varnish layer appears on the surface of the material after drying. Reference is made to Figure 1, which illustrates the varnish layer on the surface of the material of the invention when red pozzolan particles with an average particle size between 200 and 300 microns are used.Drops of water applied to the surface illustrate the highly hydrophobic nature of the surface, in addition to the visibility of the varnish on the surface of the material.

[0039] The appearance of this varnish layer has advantages, particularly aesthetic ones, since the use of this particle size allows for the production of paints without additives and without the additional addition of a varnish layer.

[0040] According to the invention, and more particularly when the material of the invention is used for application on a cement or a base coat and before application of a lime wash, the pozzolan particles have a particle size of less than 600 microns obtained by particle size cutting at 600 microns, preferably less than 500 microns obtained by particle size cutting at 500 microns, and more preferably less than 450 microns obtained by particle size cutting at 450 microns, the volume ratio between lime and pozzolan in the dry mass is preferably greater than 2 and less than 5 and more preferably between 3 and 4.

[0041] The invention also relates to a dry mass kit for manufacturing the construction material of the invention, comprising the dry mass of the material as previously described. Before use, the dry mass of the kit is mixed with water in the proportions previously indicated, depending on the application of plaster or paint.

[0042] Comparative tests are presented below to highlight the advantageous properties of the coating material of the invention.

[0043] Example 1: Comparative tests between the material of the invention comprising air lime and a material comprising hydraulic lime

[0044] In this example, a mortar is made from a dry mass consisting of natural red pozzolan from Réunion Island with a particle size of less than 2 millimeters, and air lime or hydraulic lime in the counter-example. The volume ratio between lime and pozzolan in the dry mass is 1.5. The volume ratio between the dry mass and water is 2.5.

[0045] A block of mortar measuring 4 cm x 4 cm x 16 cm is prepared and dried for 28 days.

[0046] Mechanical resistance tests in bending are carried out according to the French standard NF EN 1015-11. The results are shown in Table 1 below. [Table 1] The mechanical performance of the material is similar to that of the lime used in the mixture, whether aerial lime or hydraulic lime.

[0048] Example 2: Comparative tests between the material of the invention comprising natural pozzolan and a material comprising crushed brick.

[0049] As in Example 1, a mortar is made using a dry mass consisting of natural red pozzolan from Réunion Island with a particle size of less than 0.5 millimeters and less than 1 millimeter (particle sizes of 0.5 millimeters and 1 millimeter respectively), or crushed brick of the same particle sizes, and air lime. The volume ratio between the lime and the pozzolan or crushed brick in the dry mass is 1.5. The volume ratio between the dry mass and water is 2.5.

[0050] A block of mortar measuring 4 cm x 4 cm x 16 cm is prepared and dried for 28 days.

[0051] Mechanical resistance tests in bending are carried out according to the French standard NF EN 1015-11. The results are shown in Table 2 below. [Table 2] 6052] Mechanical resistance tests in compression are also carried out according to the French standard NF EN 1015-11. The results are shown in Table 3 below. [Table 3] 6053] It is observed that the mechanical performance of the material according to the invention, comprising pozzolana as a mineral material, is substantially superior to that of a material comprising crushed brick, even though crushed brick induces pozzolanic reactions with air lime.

[0054] Example 3: Comparative tests between the material of the invention comprising natural pozzolana and a material comprising crushed brick.

[0055] As in Example 1, a mortar is made using a dry mass consisting of natural red pozzolan from Réunion Island with a particle size of less than 0.5 mm, less than 1 mm, and less than 2 mm (particle sizes of 0.5 mm, 1 mm, and 2 mm respectively), and air lime. The volume ratio between the lime and the pozzolan or crushed brick in the dry mass is 1.5. The volume ratio between the dry mass and water is 2.5.

[0056] A block of mortar measuring 4 cm x 4 cm x 16 cm is prepared and dried for 28 days.

[0057] Mechanical resistance tests in bending are carried out according to the French standard NF EN 1015-11. The results are shown in Table 4 below. [Table 4]

[6058] Mechanical resistance tests in compression are also carried out according to the French standard NF EN 1015-11. The results are shown in Table 5 below. [Table 5]

[0059] It is observed that the compressive mechanical performance of the material according to the invention for a pozzolan particle size of less than 1 millimeter is significantly higher than that obtained for a pozzolan particle size of less than 2 millimeters. While decreasing mechanical performance might be expected with increasing particle size, the results obtained for a particle size of less than 1 millimeter exceed expectations, particularly with regard to compressive strength.

[0060] Example 4: Comparative particle size tests and demonstration of the presence of a varnish layer.

[0061] As in Example 1, a mortar is made using a dry mass mixture of air lime and natural red pozzolan from Réunion Island with a particle size of less than 2 millimeters. The volume ratio of lime to pozzolan or crushed brick in the dry mass is 1.5. The volume ratio of the dry mass to water is 2.5.

[0062] Several mortar blocks measuring 4 cm x 4 cm x 16 cm are prepared from pozzolan particles of varying particle sizes, obtained through different granulometric cuts, for example, by sieving with sieves having opening diameters ranging from 50 microns to 2 millimeters. The mortar blocks are then dried for 28 days.

[0063] The presence or absence of a glaze on the surface of each mortar sample after drying was observed. The ease or difficulty of applying the mortar to the work surface before drying was also noted. The results are shown in Table 6 below. [Table 6]

[0064] "Varnish effect" column: - No varnish present + Presence of varnish ++ Pronounced presence of varnish

[0065] "Ease of application" column: - Difficult application + Moderately easy application ++ Easy application

[0066] It is observed that the presence of a varnish on the surface of the mortar corresponding to figure 1 is observed for pozzolan particle size sections less than 300 microns and particularly pronounced for pozzolan particle size sections less than 250 microns.

[0067] It is observed that the application of the mortar on the working surface is easy for particle size cuts between 2 millimeters and 200 microns, that the application is average for particle size cuts of 150 and 100 microns and that the application is difficult for a particle size cut of 50 microns.

[0068] It follows that the varnish effect obtained by the material of the invention on the mortar is optimal for a particle size distribution of the pozzolan particles between 100 and 300 microns, preferably between 200 and 300 microns and more preferably between 200 and 250 microns for which particle size distributions the application of the mortar is also easy.

[0069] Within the framework of the invention, it is possible to provide a mixture of pozzolana particles resulting from several particle size cuts according to the values ​​previously explained. Example 5: Composition of the coating material and comparative tests

[0070] In this example, the coating material is applied to cement or a base coat, possibly containing additives, before the application of a decorative lime wash, preferably without additives. Thus, the material of the invention is located between the cement or base coat and the lime wash. It is therefore essential that the material of the invention adhere to the cement or base coat while allowing the lime wash to create the desired visual appearance.

[0071] For this purpose, the pozzolan particles have a particle size of less than 600 microns, obtained by particle size analysis, for example, by sieving natural pozzolan through a sieve with a 600-micron opening diameter. This sieving process yields pozzolan particles with a particle size of less than 600 microns. Such a particle size prevents the pozzolan particles from being visible after the application of the lime wash.

[0072] A particle size of less than 500 microns, obtained by a 500-micron smear, or less than 450 microns, obtained by a 450-micron smear, is preferred. Below 450 microns, the pozzolan particles are too fine and penetrate the base coat.

[0073] Furthermore, in this example, the dry mass of the coating material consists solely of air lime and volcanic pozzolan particles of a previously defined grain size, this dry mass being mixed only with water. Thus, the coating material is devoid of water-retaining agents, as well as sand, clay, and a binding agent. It may be optional to include natural pigments in the dry mass to provide a base color for the lime wash.

[0074] In this example, the volcanic pozzolan is natural red volcanic pozzolan but could also be grey pozzolan.

[0075] Furthermore, in this example and according to the invention, the ratio of air lime to pozzolan in the dry mass is greater than 1, and more particularly greater than or equal to 2. Below a ratio of 2, the mixture does not contain sufficient binder but nevertheless allows for application according to the invention. Preferably, the ratio of air lime to pozzolan in the dry mass is greater than or equal to 3 and less than 9, and more preferably between 6 and 8.

[0076] Table 7 below shows the different tests performed according to the particle size distribution and the ratio of lime to pozzolan. For each test, the material consists only of air lime, pozzolan particles, and water. Furthermore, the water-to-dry-mass ratio is between 1 and 1.5, but this ratio can be modified according to the desired viscosity of the coating material. [Table 7]

[6077] Thus, according to this example and according to the results presented, the material of the invention consists of a mixture of air lime and reactive mineral matter consisting exclusively of natural volcanic pozzolan particles of a grain size of less than 600 microns obtained by granulometric section at 600 microns, preferably less than 500 microns obtained by granulometric section at 500 microns, and more preferably less than 450 microns obtained by granulometric section at 450 microns, the volume ratio between the lime and the pozzolan in the dry mass being greater than 1, preferably greater than 2 and less than 5, and more preferably between 3 and 4.

Claims

DEMANDS

1. Construction coating material, characterized in that it comprises a mixture of water and dry mass, said dry mass comprising a mixture of air lime and reactive mineral material consisting exclusively of natural volcanic pozzolan particles of a grain size less than 2 millimeters which have not undergone any transformation.

2. A building coating material according to the preceding claim, characterized in that said material is free of water-retaining agents.

3. A building coating material according to any one of the preceding claims, characterized in that said material is free of sand, clay, and fixing agents.

4. Construction coating material according to any one of the preceding claims, characterized in that it consists of a mixture of air lime and reactive mineral material consisting exclusively of natural volcanic pozzolan particles of a grain size less than 2 millimeters which have not undergone any transformation, and optionally of a natural pigment or a mixture of natural pigments.

5. Construction coating material according to any one of the preceding claims, characterized in that the natural volcanic pozzolan particles have a particle size of less than 1 millimeter.

6. Construction coating material according to any one of claims 1 to 4, characterized in that the natural volcanic pozzolan particles have an average particle size of less than 600 microns, preferably less than 500 microns and more preferably less than 450 microns.

7. Construction coating material according to any one of the preceding claims, characterized in that the volume ratio of lime to pozzolana in the dry mass is greater than 1.

8. Construction coating material according to any one of the preceding claims, characterized in that the volume ratio of lime to pozzolana in the dry mass is greater than 2 and less than 5, preferably between 3 and 4.

9. A building coating material according to the preceding claim, characterized in that it consists of a mixture of air lime and of reactive mineral material consisting exclusively of natural volcanic pozzolana particles with a grain size of less than 600 microns, preferably less than 500 microns, and more preferably less than 450 microns, and optionally of a natural pigment or a mixture of natural pigments.

10. Coating material according to the preceding claim, characterized in that the volume ratio between water and dry mass is between 1 and 1.

5. [Claim 1 1] Construction coating material according to any one of claims 1 to 5, characterized in that the volume ratio of lime to pozzolan in the dry mass is greater than 1, in that the volume ratio of dry mass to water is between 2 and 3.5, preferably between 2.5 and 3.3, and in that the particle size of the pozzolan particles is less than 2 millimeters.

12. Construction coating material according to the preceding claim, characterized in that the volume ratio between dry mass and water is between 2 and 3.5, preferably between 2.5 and 3.3, and in that the pozzolan particles are obtained from one or more particle size cuts between 100 and 300 microns, preferably between 200 and 300 microns and more preferably between 200 and 250 microns.

13. Construction coating material according to any one of claims 1 to 5, characterized in that the water-to-dry-mass volume ratio is between 0.8 and 1.4 and in that the particle size of the pozzolan particles is less than 0.5 millimeters.

14. Construction coating material according to any one of the preceding claims, characterized in that the natural volcanic pozzolan is red natural volcanic pozzolan.

15. Dry mass kit for preparing a construction coating material according to any one of the preceding claims, characterized in that said dry mass comprises a mixture of air lime and mineral matter consisting exclusively of natural volcanic pozzolan particles of a grain size less than 2 millimeters which have not undergone any transformation.

16. Kit according to the preceding claim, characterized in that the dry mass is free from sand, clay, fixing agent and water retaining agent.

17. Kit according to any one of claims 15 and 16, characterized in that the natural volcanic pozzolan particles have an average grain size of less than 1 millimeter.

18. Kit according to any one of claims 15 to 17, characterized in that the natural volcanic pozzolan is red natural volcanic pozzolan.

19. Kit according to any one of claims 15 to 18, characterized in that the volume ratio of lime or lime mixture and pozzolana in the dry mass is greater than 1.

20. Kit according to any one of claims 15 to 19, characterized in that the dry mass consists of a mixture of air lime and reactive mineral material consisting exclusively of natural volcanic pozzolan particles of a particle size less than 600 microns, preferably less than 500 microns, preferably less than 450 microns, which have not undergone any transformation, and optionally of a natural pigment or a mixture of natural pigments, and in that the volume ratio between lime and pozzolan in the dry mass is greater than 2 and less than 5, preferably between 3 and 4.

21. Use of the construction coating material of claim 10 for application on a base coat and prior to application of a lime wash.

22. Use of the construction coating material of claims 11 and 12 as a coating or as a finishing coating.

23. Use of the construction coating material of claim 13 as an interior or exterior wall paint.

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