MATERIAL

The present invention relates to a composition suitable for use as a construction material and to a process for the production of said composition.

The most commonly used construction material is concrete. One of the main advantages of concrete is its low production cost, in particular for ordinary concretes. However, in certain cases, it may be desirable to use a construction material other than concrete or an alternative form of concrete.

When talking about concrete in the present description, it is understood mortar or concrete. A mortar has quite the same composition as a concrete, but the biggest particles of a mortar are smaller than the biggest particles of a concrete.

There is a present trend to produce concretes with minimum negative impact on the environment. One criterion to measure the impact of a concrete on the environment corresponds to the total equivalent cost of carbon dioxide, or "C0 ₂ footprint" which comprises taking into account all the production steps and the exploitation of the concrete. The C0 ₂ footprint may be given in kilogramme of C0 ₂ per cubic metre of hardened concrete. The total C0 ₂ footprint comprises the C0 ₂ footprint of the concrete's raw materials, the C0 ₂ footprint of the production of the concrete itself (mixing the components of the concrete), the C0 ₂ footprint of the transportation of the concrete from the production site to the usage site, the C0 ₂ footprint of implementation of the concrete, etc. Such costs are described in the ISO 14064 - FGE Carbon Standard.

The C0 ₂ footprint of Portland cement is a major contribution to the total C0 ₂ footprint of concrete. Replacing in part or totally Portland cement with an alternative binder with lower C0 ₂ footprint is thus a way of reducing the C0 ₂ footprint. However, it may be difficult to find such a binder that allows for adequate mechanical strength and cohesion of concrete.

Therefore, the problem which the invention intends to solve is to provide a new material suitable for use in the construction industry that may, for certain applications, replace ordinary mortar or ordinary concrete and for which the C0 ₂ footprint is less than the C0 ₂ footprint of the ordinary mortar or ordinary concrete.

The applicants have developed a premix that comprises a particulate material and a binder material characterised in that

(1) the particulate material comprises:

- 1 to 50% by weight of a first material comprising ultrafine particles, said ultrafine particles having a Dv90 less than 8 μηι or a BET specific surface area greater than - 1 to 70% by weight of a second material comprising fine particles, said fine particles having a Dv10 and a Dv90 from 1 to 100 μηι or a BET specific surface area less than or equal to 5 m ² /g;

- 1 to 70% by weight of a third material comprising medium particles, said medium particles having a Dv10 and a Dv90 greater than 100 μηι and less than or equal to

5 mm;

(2) the binder material comprises:

- a phosphate ion, an oxalate ion or a mixture thereof; and

- an alkaline earth metal.

The premix as described above is generally present in the dry form, that is to say substantially in the absence of a liquid or a solvent.

An advantage of the composition according to the invention, when the premix is mixed with water and optionally aggregates and admixtures, is that it may be used as construction material, in particular to replace an ordinary mortar or an ordinary concrete.

The invention provides another advantage in that the equivalent cost in C0 ₂ for production of the premix or the composition according to the invention is less than the C0 ₂ footprint for production of an ordinary mortar or an ordinary concrete. Indeed, the C0 ₂ footprint of Portland cement is significant due to the decarbonation of limestone at 900°C, as well as to the thermal energy required to heat the kiln to around 1400°C for clinkering. In contrast, the components of the premix or of the composition according to the invention do not necessitate such high-temperature processing steps.

D _v 90 generally corresponds to the 90 ^th percentile of the particle size distribution by volume, that is to say that 90% of the particles have a size less than or equal to Dv90 and 10% of the particles have a size greater than Dv90. Likewise, Dv10 generally corresponds to the 10 ^th percentile of the particle size distribution by volume, that is to say that 10% of the particles have a size less than or equal to Dv10 and 90% of the particles have a size greater than Dv10.

The term "particulate" as used within the scope of the present invention is to be understood in the broad sense and not only corresponds to compact particles having a more or less spherical shape but also for example to angular particles, flattened particles, flake-shaped particles or fibre-shaped particles.

The "size" of the particles is to be understood within the scope of the present invention as the smallest transverse dimension of the particles. By way of example, in the case of fibre-shaped particles, the size of the particles corresponds to the diameter of the fibres. Particles of a material are to be understood as the particles taken individually (which is to say the unitary elements of the material) given that the material may be in the form of agglomerates of particles.

The term "average size" is generally understood as the size of the particle which corresponds to the 50 ^th percentile (by volume), that is to say that 50% of the particles have a size less than or equal to the average size and 50% of the particles have a size greater than the average size.

The particulate material of the premix of the present invention comprises a first material comprising ultrafine particles. The ultrafine particles have a Dv90 less than 8 μηι or a BET specific surface area greater than 5 m ² /g.

The ultrafine particles may be selected from alkaline earth metal carbonate, Portland cement, natural and artificial pozzolans, pumice, ground fly ash, particles of ground hydrated or carbonated siliceous hydraulic binder and mixes or co-grindings thereof, in the dry form. The ground hydrated siliceous hydraulic binder suitable for use in the premix according to the invention may be those as detailed in the FR 2708592. The alkaline earth metal is preferably an alkaline earth metal carbonate, more preferably calcium carbonate or magnesium carbonate, even more preferably calcium carbonate.

The first material comprising ultrafine particles is present from 1 to 50% by weight of the total premix. Preferably, the first material is present from 1 to 40%, more preferably from 5 to 20% by weight of the total premix.

The particulate material of the premix of the present invention comprises a second material comprising fine particles. The fine particles have a Dv10 and a Dv90 from 1 μηι to 100 μηι or a BET specific surface area less than or equal to 5 m ² /g. Preferably, the fine particles have a Dv10 and a Dv90 from 1 to 100 μηι and a BET specific surface area less than or equal to 5 m ² /g. Preferably, the fine particles have a Dv90 greater than or equal to 8 μηι.

The fine particles may be selected from alkaline earth metal carbonate, Portland cement, fly ash, pozzolans (natural and artificial), siliceous powders, lime, calcium sulphate (in particular gypsum in the anhydrous or hemi hydrate form), slags and mixtures thereof.

Preferably, the fine particles are selected from alkaline earth metal carbonate. Preferably, the alkaline earth metal is calcium or magnesium or a mixture thereof. More preferably, the carbonate is calcium carbonate. The carbonate compound may be used as ground or precipitated carbonate, preferably ground carbonate. The commercial calcium carbonate product Durcal 15™ sold by OMYA (France) suitably may be used in the premix or the composition of the present invention. The second material comprising fine particles is present from 1 to 70% by weight of the total premix. Preferably, the second material is present from 1 to 50%, more preferably from 20 to 40% by weight of the total premix.

According to an embodiment, there may be an overlap between the sizes of the fine and ultrafine particles, which is to say that more than 10% of the ultrafine particles and more than 10% of the fine particles may be within the same range of size.

An example of a case where the ultrafine and fine particles are only differentiated by the BET specific surface area and not by the size of the particles may be the one where the ultrafine particles comprise particles of ground hydrated hydraulic binder. In this example, the ultrafine particles may have a size around 10 μηι and a specific surface area which may be around 100 m ² /g (due to the porosity of this material).

The particulate material of the premix of the present invention comprises a third material comprising medium particles. The medium particles have a Dv10 and a Dv90 greater than 100 μηι and less than or equal to 5 mm.

The medium particles may be selected from calcium carbonate or sand. The sand may be of any limestone, siliceous or silico-limestone or other mineral nature. The sand is generally limestone sand, silica sand, calcined bauxite or particles of metallurgic waste. The sand may also comprise a dense ground mineral material, for example vitrified ground slag. The medium particles may be the product commercialised under the name "Cassis 0-1.6 mm" by Lafarge (France). The Cassis sand has a Dv10 of 0.2 mm and a Dv90 of 1.3 mm.

The third material comprising medium particles is present from 1 to 70% by weight of the total premix. Preferably, the third material is present from 30 to 60% by weight of the total premix.

A preferred premix according to the present invention comprises from 1 to 40%, more preferably from 5 to 20% of the first material by weight of the total premix; from 1 to 50%, more preferably from 20 to 40% of the second material by weight of the total premix; and from 30 to 60% of the third material by weight of the total premix.

The particulate material of the premix may comprise a fourth material comprising particles having a Dv10 greater than 5 mm. Preferably, the fourth material comprises particles having a Dv10 less than or equal to 10 mm.

The fourth material may be gravels. The gravels may be of any limestone, siliceous or silico-limestone nature.

The fourth material is present from 1 to 70% by weight of the total premix. Preferably, the fourth material is present from 30 to 60% by weight of the total premix.

Where the particulate material of the premix according to the invention comprises the fourth material, the relative proportions of the preferred premix are from 1 to 50% of the first material, from 1 to 70% of the second material, from 1 to 70% of the third material and from 1 to 70% of the fourth material. The proportions are expressed in weight percentage of the total premix.

The premix of the present invention comprises a binder material comprising an alkaline earth metal and a phosphate ion or an oxalate ion or a mixture thereof. The alkaline earth metal may be provided by the first material and/or the second material and/or a further material added to the dry premix. The alkaline earth metal is preferably calcium or magnesium, more preferably calcium. Preferably, the binder material comprises an alkaline earth metal and a phosphate ion.

When the binder of the premix comprises calcium as alkaline earth metal and a phosphate ion, the molar ratio between calcium and phosphate is preferably from 1 to 2, more preferably about 1.67 to form hydroxyapatite. When the binder of the premix comprises calcium as alkaline earth metal and an oxalate ion, the molar ratio between calcium and oxalate is preferably about 1.

A preferred premix according to the present invention comprises from 80 to 99.9%, preferably from 85% to 99%, more preferably from 90% to 99% of the particulate material by weight of the total premix; and from 0.1 to 20%, preferably from 1 % to 15%, more preferably from 1 % to 10% of the binder material by weight of the total premix.

The present invention also provides a composition comprising the premix as described herein above and a solvent.

The premix according to the invention may be mixed with a solvent, and optionally additives to obtain a composition that may be used as an alternative to ordinary mortars or to ordinary concretes. The preferred solvent is water. Where additives are used, the suitable additives may be superplasticizers.

The term "superplasticizer" is to be understood as an organic molecule used in the field of hydraulic compositions or other mineral charges in order to fluidize the said hydraulic compositions or the said other mineral charges. A superplasticizer may in particular be a superplasticizer/high water-reducer as defined in the EN 934-2 Standard in paragraph 3.2.3. The superplasticizer is preferably a polyoxy ethylene polycarboxylate/polyoxy propylene polycarboxylate.

The expression "polyoxy ethylene polycarboxylate/polyoxy propylene polycarboxylate" or "PCP" is to be understood as a copolymer of acrylic acids and/or methacrylic acids, of their esters of polyoxy ethylene/polyoxy propylene (POE/POP) or their ethers of POE/POP. The expression "polyoxy ethylene/polyoxy propylene" is to be understood in the present description as polyoxy ethylene, or polyoxy ethylene and polyoxy propylene. Another example of additives may be additives to obtain a cohesive hardened composition, as alginate or chitosan.

The present invention also provides a process for the production of the composition. The process comprises a step of mixing the particulate material and the alkaline earth metal of the binder material with a solution of the phosphate ion and/or the oxalate ion of the binder material. The solution of the phosphate ion and/or the oxalate ion of the binder material is preferably a solution comprising a soluble compound selected from a hydrogen phosphate ion, a dihydrogen phosphate ion, a phosphoric acid, a phosphoric acid ester, an oxalic acid and mixtures thereof. Most preferably, the solution comprises a soluble compound selected from a hydrogen phosphate ion, a dihydrogen phosphate ion, phosphoric acid, a phosphoric acid ester and mixtures thereof. Especially, the solution comprises a hydrogen phosphate ion, for example a diammonium hydrogen phosphate.

Preferably the solution of the phosphate ion and/or the oxalate ion of the binder material is an aqueous solution.

According to an example of embodiment of the invention, the weight concentration of the soluble compound in the solution is from 0.1 % to 60%, preferably from 1 % to 50%, more preferably from 10 to 40%.

The soluble compound based on phosphate and/or oxalate reacts with the alkaline earth metal (provided by the first material and/or the second material and/or a further material added to the composition) to form a solid precipitate comprising the alkaline earth metal and the compound or a derivative of the compound. The precipitate settles on the particles of the particulate material and forms bridges between the particles.

According to an example of embodiment of the invention, when the alkaline earth metal is provided by a calcium carbonate (CaC0 ₃ ) and the soluble compound is a hydrogen phosphate ion (for example in the form of diammonium hydrogen phosphate ((NH ₄ ) ₂ HP0 ₄ ), the reaction (1) forming the binder is the following:

10CaCO ₃ (s)+ 6HP0 ₄ ^2" _(aq) → Ca ₁₀ (PO ₄ ) ₆ (OH) _{2 (s)} + 8HC0 ₃ ^" _(aq) + 2C0 ₃ ^2" _(aq) (1)

The subscript (aq) means that the corresponding chemical species is dissolved in solution whilst the subscript (s) means that the corresponding chemical species is in the solid state. The binder comprises hydroxyapatite in this example. Depending on the relative proportions of calcium and phosphate, the binder may comprise a range of calcium orthophosphates such as calcium deficient hydroxyapatite, amorphous calcium phosphate, octacalcium phosphate or dicalcium phosphate dehydrate (brushite).

According to an example of embodiment of the invention, when the alkaline earth metal is provided by a magnesium carbonate (MgC0 ₃ ) and the soluble compound is a dihydrogen phosphate ion (for example in the form of potassium dihydrogen phosphate

(KH ₂ P0 ₄ )), the reaction (2) forming the binder is the following:

MgCOs (s) + K ⁺ _(aq) + H2PO4- ₍ aq)→ KMgP0 ₄ «6H ₂ 0 _(s) + C0 _{2 (g)} (2)

When the compound is a phosphoric acid ester, the compound has the following general formula:

O

II

RIO -P-OR3

R20

in which the R ¹ , R ² and R ³ , which may be identical or different, are hydrogen, a metal, for example Na or Ca, or an alkyl or alkylene group; at least one of the R ¹ , R ² and R ³ groups being an alkyl, alkylene group, or a group representing a polyol or a carbon hydrate, for example, glucose or glycerol.

Examples of phosphoric acid ester are methyl phosphate (R ¹ = CH ₃ ; R ² = R ³ = H); di-ethyl phosphate (R ¹ = R ² = C ₂ H ₅ ; R ³ = H); tri-n-butyl phosphate (R ¹ = R ² = R ³ = n- C ₄ H ₉ ); sodium ethylene glycol cyclic phosphate (R ¹ + R ² = CH ₂ CH ₂ ; R ³ = Na), etc. In certain cases, the ester may also be a polymer or oligomer, for example copolymers and oligomers produced by esterification of 1 ,4-butanediol with phosphoric acid.

At ambient temperature, the phosphoric acid ester in aqueous solution reacts with the alkaline earth metal to form a phosphate of the solid alkaline earth metal and alcohols (R ¹ OH, R ² OH and R ³ OH) which remain in solution according to, for example, the following reaction (3), when the alkaline earth metal is calcium:

2P0 ₄ R ¹ R ² R ³ _(aq) + 3CaC0 _{3 (s)} <→ Ca ₃ (P0 ₄ ) _{2 (s)} + R ¹ OH _(aq) + R ² OH _(aq) + R ³ OH _(aq) + 3C0 _{2 (g)}

(3)

The phosphoric acid ester tends to release phosphoric acid in solution which reacts with the alkaline earth metal. The use of a phosphoric acid ester may be advantageous inasmuch as the quantity of phosphoric acid may be progressively released in solution, by modifying the equilibrium of the reaction (3), in particular by heat, using catalysers, etc. The speed at which the solid binding phases are formed can then be controlled.

The solution may be mixed with the powder. The mixing may be carried out in a mixer. The solution and the powder may be heated.

According to an example of embodiment, the ultrafine particles and the fine particles are mixed beforehand and the assembly constituted of the ultrafine particles and the fine particles is then mixed with the solution. The medium particles and optionally the fourth material may then be added to the mix. According to an example of embodiment, the ultrafine particles, the fine particles and the medium particles are mixed beforehand and the assembly constituted of the ultrafine particles, the fine particles and the medium particles is then mixed with the solution. The fourth material may then be optionally added to the mix.

The composition obtained from the premix according to the invention may be used to produce an element for the construction field.

The present invention also provides an element for the construction field, obtained from a composition as previously defined.

An element for the construction field corresponds to any element constituting a construction, for example a floor, a screed, a foundation, a basement, a wall, a partition wall, a ceiling, a beam, a work top, a pillar, a bridge pier, a concrete block, a pipe, a pipeline, a column, stairs, a panel, a cornice, a mould, an element of road works (for example a border of a pavement), a roof tile, coating material (for example for roads or walls) or an acoustic or thermal insulating element.

According to an example of embodiment, the element has a compressive strength after production of the element greater than 2 MPa, preferably greater than 4 MPa, more preferably greater than 15 MPa. The compressive strength of the element is measured for example according to the method as described in the NF EN 196-1 Standard « Methode d'essai des ciments - Partie 1 : Determination des resistances mecaniques » ["Cement Test Method - Part 1: Determination of the mechanical strengths"].

According to an example of embodiment of the invention, the porosity or air content of the element is from 1 % to 30% of voids relative to the volume of the element. The measurement of the air content of the element may be carried out by a measurement of the density, for example with Archimedes's method.

The present invention also provides a process for the production of an element for the construction field. The process may comprise the following steps:

- mixing of the particulate material and a solution of the binder material;

- casting of the flowable composition obtained;

- setting of the composition; and

- demoulding of the element.

In this case, the mixing of the powder of the fine particles, the ultrafine particles and the medium particles (and optionally the fourth material) with the solution is carried out before the casting. A pressure greater than the atmospheric pressure is preferably applied to the cast composition to facilitate the evacuation of the excess solution.

Alternatively, the process for the production of an element for the construction field may comprise the following steps: - mixing of the particulate material;

- casting of the particulate material in the dry state;

- application of a pressure greater than the atmospheric pressure to the cast composition;

- placing the pressed cast particulate material in a bath of a solution of the binder material.

Several methods may be envisaged for the last step described herein above:

- according to an embodiment, the solution of the binder material penetrates by capillarity in the pressed cast particulate material. By way of example, the powder is compacted in a mould to form a block. The solution can then penetrate into the block by imbibition;

- according to another embodiment, the solution of the binder material penetrates by aspiration in the pressed cast particulate material. By way of example, the block of powder is placed in an enclosure. The bottom end of the block is soaked in the solution. An aspiration inlet is placed in the enclosure on the side of the top end of the block of powder. The solution penetrates the block by the action of the aspirating force.

Alternatively, the process for the production of an element for the construction field may comprise the following steps: mixing of the particulate material with water and optionally a solution of the binder material, before casting, applying a pressure greater than the atmospheric pressure and placing the pressed cast material in a bath of a solution of the binder material.

In all cases, when a pressure higher than atmospheric pressure is applied to the cast composition, the pressure is for example greater than 1 MPa, preferably greater than 10 MPa. The cast composition may further be heated, for example to a temperature higher than 30°C.

A reactive sintering operation of the particles of alkaline earth metal may further be carried out. The sintering operation may be carried out by exposing the cast composition to a flow of gas comprising carbon dioxide, for example at a pressure greater than or equal to the atmospheric pressure.

In all the embodiments described herein above, the phosphate and/or the oxalate and/or the particles of alkaline earth metal may be heated before being mixed and/or during the mixing. The heating operation may make it possible to accelerate the reaction forming the solid precipitate comprising the alkaline earth metal and the compound or a derivative of the compound. Moreover, the heating may be sufficient to entrain at least a partial evaporation of the solution and hence make it possible to control the porosity of the obtained element for the construction field. The Dv10 of the Dv90 of an assembly of particles may generally be determined by laser granulometry for the particles with a size less than 63 μηι, or by sieving for the particles with a size greater than 63 μηι.

The BET specific surface area is a measurement of the real total surface of particles, which takes into account the presence of reliefs, irregularities, superficial cavities and internal porosity.

The size, the average size, the Dv10 or the Dv90 of an assembly of particles may generally be determined by laser granulometry, for example using a Malvern Mastersizer 2000 granulometre. The particle size measurement may be carried out by the wet method (aqueous medium); the size of the particles must be from 0.01 μηι to 2 mm. The light source is provided by a red laser He-Ne (632 nm) and a blue diode (466 nm). The optical model is the Fraunhofer model, the calculation matrix is the polydisperse type.

A measurement of the background noise is first carried out at a pump speed of 2000 rpm, a stirrer speed of 800 rpm and a noise measurement for 10 seconds, in the absence of ultrasound. The light intensity of the laser is verified to be at least equal to 80%, and a decreasing exponential curve is obtained for the background noise. Otherwise, the lenses of the cell must be cleaned.

A first measurement is carried out on the sample with the following parameters: pump speed: 2000 rpm, stirrer speed: 800 rpm, absence of ultrasound, obscuration limit between 10 and 20%. The sample is introduced to have an obscuration slightly greater than 10%. After stabilisation of the obscuration, the measurement is carried out with a duration between immersion and measurement set at 10 seconds. The duration of the measurement is 30 seconds (30000 diffraction images analyzed). In the obtained granulogram, it has to be taken into account the fact that part of the particles of the powder could be agglomerated.

A second measurement is then carried out (without emptying the tank) with ultrasound. The pump speed is increased to 2500 rpm, the stirrer speed to 1000 rpm, ultrasound is emitted at 100% (30 watts). These conditions are maintained for 3 minutes, then the initial parameters are restored: pump speed: 2000 rpm, stirrer speed: 800 rpm, absence of ultrasound. After 10 seconds (to evacuate possible air bubbles), a measurement is carried out for 30 seconds (30000 images analyzed). This second measurement corresponds to a de-agglomerated powder by ultrasonic dispersion.

Each measurement is repeated at least twice to verify the stability of the result. The apparatus is calibrated before each working session using a standard sample (silica C10 Sifraco) the granulometric curve of which is known. All the measurements presented in the description and the indicated ranges correspond to the values obtained with ultrasound.

The BET specific surface area of a particulate material may be measured as follows. A sample of powder is taken of the following mass: 0.1 to 0.2 g for a specific surface area estimated at more than 30 m ² /g; 0.3 g for a specific surface area estimated at 10-30 m ² /g; 1 g for a specific surface area estimated at 3-10 m ² /g; 1.5 g for a specific surface area estimated at 2-3 m ² /g; 2 g for a specific surface area estimated at 1.5- 2 m ² /g; 3 g for a specific surface area estimated at 1-1.5 m ² /g.

A 3 cm ³ or a 9 cm ³ cell is used depending on the volume of the sample. The measurement cell assembly (cell + glass rod) is weighed. Then the sample is added to the cell: the product must not be less than one millimetre from the top of the neck of the cell. The assembly is weighed (cell + glass rod + sample). The measurement cell is placed on a degassing unit and the sample is degassed. The degassing parameters are 30 min/45°C for Portland cement, gypsum, pozzolans; 3 h/200°C for slags, fly ash, aluminous cement, limestone; and 4 h/300°C for the control alumina. The cell is rapidly closed with a stopper after degassing. The assembly is weighed and the result noted. All the weighing is carried out without the stopper. The mass of the sample is obtained by subtracting the mass of the cell from the mass of the cell + degassed sample.

The analysis of the sample is then carried out after placing it on the measurement unit. The analyzer is the SA 3100 de Beckman Coulter. The measurement is based on the adsorption of nitrogen by the sample at a given temperature, in this case the temperature of liquid nitrogen, that is -196°C. The apparatus measures the pressure of the reference cell in which the adsorbate is at its saturated vapour pressure and that of the sample cell in which known volumes of adsorbate are injected. The resulting curve of these measurements is the adsorption isotherm. In the measurement process it is necessary to know the dead space of the cell: a measurement of this volume is therefore carried out with helium before the analysis.

The mass of the sample, calculated beforehand is entered as a parameter. The BET surface is determined by the software by linear regression from the experimental curve. The standard deviation of reproducibility obtained from 10 measurements on a silica having a specific surface area of 21.4 m ² /g is 0.07. The standard deviation of reproducibility obtained from 10 measurements on a cement having a specific surface area of 0.9 m ² /g is 0.02. A control is carried out once every two weeks on a reference product. Twice a year a control is carried out with reference alumina provided by the manufacturer.

In the present description and the related claims, it is understood that "a" or "an" means "one or more". EXAMPLES

The present invention is illustrated by the following non-limiting examples. In examples the products and materials used are available from the following suppliers:

The limestone Durcal 1 had a Dv50 of 2 μηι.

The limestone Durcal 15 had a Dv50 of 21 μηι.

The limestone sand had a Dv50 less than or equal to 0.8 mm.

The additive F2 was a superplasticizer comprising a polyoxyalkylene polycarboxylate in aqueous phase (30 wt.% solids).

Mortar mixtures were mixed in a 4-L capacity Perrier mixer. All solids were first homogenized for 1 minute at low speed (140 rpm). Water with dissolved superplasticizer was then added to all the solid powder. The mixture was mixed for 9 minutes at low speed, then mixed for an additional minute at high speed (340 rpm). The fluid mortar mixture was then poured into prismatic moulds (4 cm x 4 cm x 16 cm), demoulded after 24 hours, and then cured under ambient laboratory conditions (20 °C, 50% of relative humidity) unless otherwise noted.

Spread flow measurements were made on the fresh mortar mixture using a flattened cone measuring 10 cm in diameter at the top, 5 cm in diameter at the bottom, and 15 cm in height. After filling this mold with the mortar, the cone was gently lifted, and the mortar allowed to spread freely under it's own weight. Several diameters of the mortar were measured from which an average spread flow was determined.

Compressive strength and flexural were measured at varying times after initial mixing (e.g. 1 , 7, 10-14 days). EXAMPLE 1

The compressive strength of this mixture was 5.0 MPa after 1 day and 6.1 MPa after 7 days. Spread flow was 450 mm. The sample was stable in water, proving that the mixture was cohesive.

These compressive strength and spread flow show that the composition according to the invention may be used as an alternative to ordinary mortar or ordinary concrete. EXAMPLE 2

After moulding, the mortar of this example was placed in a 60°C oven. The compressive strength of this mixture was 2.0 MPa after 7 days, and 2.8 MPa after 14 days.

This compressive strength results show that the composition according to the invention may be used as an alternative to ordinary mortar or ordinary concrete. EXAMPLE 3

In this example, calcium salts were provided by the limestone.

After moulding, the mortar of this example was placed in a 60°C oven. The compressive strength of this mixture was 2.6 MPa after 14 days.

This compressive strength results show that the composition according to the invention may be used as an alternative to ordinary mortar or ordinary concrete.