METHOD FOR PREPARING AN ETTRINGITE BINDER FOR PRODUCING CONSTRUCTION MATERIALS

Abstract

A method for preparing an ettringite binder from an aluminosilicate source, a calcium sulfate source and a calcium hydroxide (or slaked lime, CH) source, the binder including a catalyst and/or an activator. Also the use of the ettringite binder produced by the method for producing cement, masonry cement, mortar, concrete, road binders and/or formulated lime.

Claims

1-12. (canceled)

13. An ettringite binder comprising: at least one aluminosilicate source; at least one calcium sulfate source; at least one calcium hydroxide source; and at least one activator chosen among the compounds suitable for complexing cations.

14. The ettringite binder according to claim 13, wherein the activator is chosen among sucrose, alpha hydroxy acids or the salts thereof, ethanolamines or the salts thereof, and/or catechols and the derivatives thereof.

15. The ettringite binder according to claim 13, further comprising an alkali catalyst.

16. The ettringite binder according to claim 15, wherein the quantity by mass of catalyst is in a range of more than 0% to 20% with respect to the total quantity of the binder.

17. The ettringite binder according to claim 13, wherein the aluminosilicate source is a pozzolan, a fine originating from the production of chamotte or ash of papermaking sludge.

18. The ettringite binder according to claim 13, wherein the calcium hydroxide source is slaked lime, hydraulic lime, quick lime, delayed-effect quick lime, air lime, conventional slaked lime or any commercial lime.

19. The ettringite binder according to claim 13, wherein the calcium sulfate source is chosen among anhydrite, natural gypsum or gypsum obtained as a by-product of industrial reactions.

20. The ettringite binder according to claim 13, further comprising additives.

21. The ettringite binder according to claim 13, wherein the aluminosilicate source is characterised by a pozzolanic activity index (IPZ), determined by the Chapelle test method, of from 200 to 2200 mg/g.

22. A method for preparing an ettringite binder according to claim 13, comprising the mixing of at least: an aluminosilicate source; a calcium sulfate source; a calcium hydroxide source; and at least one activator chosen among the compounds suitable for complexing cations.

23. The method of preparation according to claim 22, wherein the temperature at which the mixing is carried out is from more than 0° C. to 50° C.

24. A method for preparing cement, masonry cement, mortar, concrete, road binders and/or formulated lime, comprising adding the ettringite binder accorder to claim 13 to said cement, masonry cement, mortar, concrete, road binders and/or formulated lime.

25. The ettringite binder according to claim 13, wherein the activator is chosen among compounds suitable for complexing calcium, aluminium and/or silicon.

26. The ettringite binder according to claim 15, wherein the alkali catalyst is chosen among sodium fluoride, sodium aluminate, trisodium phosphate, sodium orthosilicate, sodium metasilicate, sodium hexafluorosilicate, sodium fluorophosphate, sodium hexametaphosphate, sodium carbonate, sodium borate, sodium hexafluoroaluminate, potassium tetrafluoroaluminate or the mixtures thereof.

27. The ettringite binder according to claim 17, wherein the aluminosilicate source is a metakaolin.

28. The ettringite binder according to claim 19, wherein the gypsum is desulfogypsum, titanogypsum, fluogypsum, or phosphogypsum.

29. The ettringite binder according to claim 20, wherein the additive is a slag, a blast furnace slag or amorphous aluminate slag.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0203] FIG. 1 is a graph showing the percentage increase in mechanical performance after 28 days, for an ettringite binder obtained from the mixture according to the invention with respect to those of a conventional pozzolanic composition, as a function of the value of the parameter RMK.

[0204] FIG. 2 is a graph showing the percentage increase in mechanical performance after 3 days (continuous line) or after 7 days (dashed line), for an ettringite binder obtained from the mixture according to the invention with respect to those of a conventional pozzolanic composition, as a function of the value of the parameter RMK.

EXAMPLES

[0205] The present invention will be better understood on reading the following examples which illustrate the invention in a non-limiting manner

Abbreviations

[0206] A: in cement chemist notation designates aluminium oxide (Al.sub.2O.sub.3) or alumina; [0207] AS2: in cement chemist notation designates a metakaolin; [0208] C: in cement chemist notation designates calcium oxide (CaO); [0209] CH: in cement chemist notation designates calcium hydroxide (Ca(OH).sub.2); [0210] C$H2: in cement chemist notation designates gypsum; [0211] C4AH13: in cement chemist notation designates tetracalcium aluminate; [0212] CxSH: in cement chemist notation designates a calcium silicate where x varies from 1 to 3, preferably from 1.2 to 2.5; [0213] C2ASH8: in cement chemist notation designates hydrated gehlenite; [0214] C4A3S: in cement chemist notation designates ye'elemite; [0215] C2S: in cement chemist notation designates belite; [0216] C$: in cement chemist notation designates calcium sulfate; [0217] C6A$3H32: in cement chemist notation designates ettringite; [0218] C4A$H20: in cement chemist notation designates tricalcium alumino monosulfate; [0219] CL: natural air lime (“calcic lime”); [0220] DSF: desulfogypsum; [0221] E/L: mass ratio of water with respect to the binder; [0222] IPZ: pozzolanic index of the metakaolin employed; [0223] L/T: mass ratio of binder with respect to the total dry matter (binder, additives, etc.); [0224] MK: metakaolin; [0225] MSLK: sodium metasilicate pentahydrate; [0226] NaHFS: sodium hexafluorosilicate; [0227] NaHFA: sodium hexafluoroaluminate; [0228] NaAlO.sub.2: sodium aluminate; [0229] NaF: sodium fluoride; [0230] P: quarry gypsum; [0231] P(C$): purity of the calcium sulfate source; [0232] R: gypsum from demolition; [0233] RMK: the quantity of calcium sulfate with respect to the quantity of metakaolin, introduced into the initial mixture and defined according to equation (e3); [0234] S: in cement chemist notation designates silicon dioxide (SiO.sub.2) or silica; [0235] S: in cement chemist notation designates sulfur trioxide (SO.sub.3); [0236] Sc: dryness in the mixture; [0237] H: in cement chemist notation designates water (H.sub.2O); [0238] Sat(CH): the mass saturation of calcium hydroxide, Ca(OH).sub.2 in a given composition; [0239] TEA: triethanolamine

[0240] Material and Methods

[0241] Material

[0242] The aluminosilicates and metakaolins are supplied by Argeco (product Argicem®) or by Imerys (products Argical M1000®, Argical M1200S, MetaStar M501), by Soka (Soka Metasial®) or are fines originating from the chamotte industry or are produced in the laboratory according to the conventional protocols.

[0243] Various limes have been supplied by LHOIST (lime LHOIST® CL80, lime LHOIST® CL90, lime LHOIST Sorbacal®) or by C.E.S.A. (slaked air lime Decorchaux® CL90). The calcium hydroxide content in these limes has been determined using the Leduc method (Hornain, 1995).

[0244] Various sources of calcium sulfate, such as gypsum, have been tested. The products have been obtained from various suppliers known to a person skilled in the art.

[0245] Properties of the Mixture According to the Invention

[0246] The mixture according to the invention is characterised by the parameters as defined below.

[0247] The pozzolanic index (IPZ) is a parameter representing the active fraction of a metakaolin, in other words the quantity of calcium hydroxide, Ca(OH).sub.2, that can be fixed in 1 gram of metakaolin. This index can be determined by the methods known to a person skilled in the art, such as by the Chapelle test for example.

[0248] The parameter Sat(CH) represents the level of saturation by mass of calcium hydroxide, Ca(OH).sub.2 in a given composition. It is determined according to the following equation (e1):

[00005]$\begin{array}{cc}\mathrm{Sat}\left(\mathrm{CH}\right)=\frac{Q\left(\mathrm{CH}\right)}{\mathrm{QST}\left(\mathrm{CH}\right)}& \left(\mathrm{e1}\right)\end{array}$

where:
Q(CH) represents the quantity in grams of calcium hydroxide (Ca(OH).sub.2) in the binder; and
QST(CH) represents the quantity in grams of calcium hydroxide necessary for the reaction forming ettringite. The parameter QST(CH) can be determined according to the following equation (e2):

[00006]$\begin{array}{cc}\mathrm{QST}\left(\mathrm{CH}\right)=\frac{\left[I.Math.P.Math.Z\times Q\left(M.Math.K\right)\times 0.0.Math.0.Math.0.Math.6.Math.2.Math.5\right]}{P\left(\mathrm{CH}\right)}& \left(\mathrm{e2}\right)\end{array}$

where:
IPZ represents the pozzolanic index as defined above;
Q(MK) represents the quantity in grams of metakaolin or aluminosilicates present in the binder; and
P(CH) represents the purity of the lime, in calcium hydroxide.

[0249] The parameter RMK represents the stoichiometric ratio of calcium sulfate with respect to the quantity of aluminosilicates, such as metakaolin, introduced in the initial mixture. The parameter QST(CH) can be determined according to the following equation (e3):

[00007]$\begin{array}{cc}R.Math.M.Math.K=\frac{\left[Q.Math.m\left(C.Math.\$\right)\times 5.Math.9.Math.2.Math.0.Math.0.Math.0\right]}{I.Math.P.Math.Z\times Q\left(M.Math.K\right)\times 3}& \left(\mathrm{e3}\right)\end{array}$

where:
IPZ represents the pozzolanic index as defined above;
Q(MK) represents the quantity in grams of metakaolins or aluminosilicates present in the binder; and
Qm(C$) represents the quantity in moles of calcium sulfate present in the binder. The parameter Qm(C$) can be determined according to the following equation (e4):

[00008]$\begin{array}{cc}\mathrm{Qm}\left(C.Math..Math.\$\right)=\frac{\left[Q\left(G\right)\times P\left(C.Math..Math.\$\right)\times S.Math.c\right]}{M}& \left(\mathrm{e4}\right)\end{array}$

where:
Q(G) represents the quantity, in grams, of calcium sulfate source introduced in the initial mixture;
P(C) represents the purity by mass of the calcium sulfate source;
Sc represents the dryness, in other words the percentage by mass of dry matter contained in the mixture.

[0250] Compressive Strength

[0251] The compressive strength tests have been performed on previously moulded compositions (cubic moulds, 40 mm×40 mm, or 10 cm×10 cm) using the Controlab E0250/15 KN class A instrument, or using cylindrical samples (16 cm×32 cm).

[0252] The compressive strength measurements have also been performed on walls using the Controlab sclerometer instrument.

Part A: Compositions

Example 1: Preparation of an Ettringite Binder According to the Method of the Invention

[0253] General Protocol

[0254] The ettringite binders according to the invention were prepared at ambient temperature, by mixing an aluminosilicate, a calcium sulfate and lime in proportions such that the ratio RMK as defined above is in the range from 0.05 to 1.25; and such that the lime saturation parameter, Sat(CH), is in the range from 0.75 to 8.

[0255] According to the invention, to this mixture (aluminosilicate/calcium sulfate/lime) can be added (i) alkali catalysts, (ii) reaction activators, and/or (iii) secondary additives such as fillers, preferably calcareous fillers.

[0256] Examples of Mixtures According to the Invention Comprising an Aluminosilicate, a Calcium Sulfate and Lime

TABLE-US-00001 TABLE 1 Examples of mixtures for preparing an ettringite binder according to the invention. Mixture No. 1 2 3 4 5 6 Alumino- Argical ® Argical ® Argical ® Chamotte Chamotte Synthesised silicate M1000 M1000 M1000 fines fines product IPZ 1000 1000 1000 850 900 600 Calcium Titano- Titano- Desulfo- Titano- Titano- Desulfo- sulfate gypsum gypsum gypsum gypsum gypsum gypsum Lime CL90 CL90 CL90 CL90 CL80 CL90 RMK 0.88 0.91 0.49 0.86 1.03 0.96 Sat(CH) 1.15 1.02 1.03 1.19 1.01 1.19 Mixture No. 7 8 9 10 11 Alumino- Argicem ® Argical ® Metastar ® Argical ® Argical ® silicate M1200S M501 M1000 M1000 IPZ 700-800 1400 950 1000 1000 Calcium Gypsum Quarry Quarry Quarry Quarry sulfate calcium calcium calcium calcium sulfate sulfate sulfate sulfate Lime CL90 CL90 CL90 CL90 CL90 RMK 0-1 0.93 0.90 0.60 0.91 Sat(CH) 1-1.1 1.10 1.07 1.10 1.07

[0257] Examples of Catalysts

[0258] Catalysts have also been added in mixtures 1 to 11 as described above (Table 1).

[0259] The catalysts employed have been chosen among: sodium fluoride, sodium hexafluoroaluminate, sodium hexafluorosilicate, sodium fluorophosphate, potassium tetrafluoroaluminate, sodium metasilicate, sodium orthosilicate, sodium trisilicate, sodium disilicate, sodium aluminate, sodium phosphate, sodium carbonate and sodium sulfate.

[0260] Examples of Activators

[0261] Activators have also been added in mixtures 1 to 11 as described above (Table 1). The activators employed have been chosen among the compounds suitable for complexing cations, in particular calcium, such as sucrose, tartaric acid, citric acid, gluconic acid, mandelic acid, lactic acid, or an ethanolamine such as triethanolamine (TEA).

Example 2: Preparation of a Material from the Ettringite Binder According to the Invention

[0262] It has been possible to obtain various materials by mixing the ettringite binder according to the invention with a quantity of water, the water being modulated according to the intended application.

[0263] During the hydration of the ettringite binder, two chemical reactions are implemented enabling ettringite to be obtained: [0264] (1) Reaction between the lime and the aluminosilicate leading to the formation of calcium aluminate (C4AH13 in cement chemist notation)

AS2+4CH.fwdarw.C4AH13+2S [0265] (2) Reaction of the calcium aluminate formed in (1) with calcium sulfate leading to the formation of ettringite

C4AH13+3C$.fwdarw.C6A$3H32+CH

[0266] The chemical equation of the hydration reaction of the ettringite binder is:

AS2+5CH+3C.fwdarw.C6A$3H32+2CSH

[0267] The following examples show the performance for the materials obtained from the ettringite binder according to the invention.

Example 3: Preparation of a Material from an Ettringite Binder Comprising a Metakaolin/Lime/Gypsum Mixture without Catalyst or Activation, and Performance of this Material

[0268] The aim of this experiment is to show the performance of a material originating from the hydration of an ettringite binder obtained from a mixture of metakaolin, lime and gypsum, for which the parameter Sat(CH) is from 1 to 1.1 for various values of the parameter RMK as defined above.

[0269] For this, a comparison has been carried out between a material originating from the ettringite binder obtained by the mixing of: [0270] flash metakaolin ARGICEM® with IPZ between 700 and 800 mg/g; [0271] a slaked lime of type CL90 with LEDUC lime content of approximately 90%; and [0272] gypsum;
and a material originating from a conventional pozzolanic composition (i.e. mixture of lime and metakaolins).

[0273] FIG. 1 is a graph showing the percentage increase in mechanical performance, after 28 days, of the mixture according to the invention with respect to those of a conventional pozzolanic composition, as a function of the value of the parameter RMK.

[0274] The results show that: [0275] for RMK values between 0 and 1, an increase in performance is always observed for the material originating from the ettringite binder according to the invention; and [0276] for RMK values between 0.25 and 0.75 an increase greater than 40% is obtained compared to the performance of a conventional pozzolanic composition.

[0277] In conclusion, these results demonstrate that the mixture according to the invention enables significant increase in the mechanical performance, after 28 days, of the product obtained from the binder according to the invention. Furthermore, the applicant has found in complementary experiments that from an RMK value of 0.6, an additional gain can be obtained depending on the nature of the gypsum.

[0278] Performance in the Early Stages

[0279] One of the major disadvantages of a conventional pozzolanic binder (i.e. a mixture of lime and metakaolin) obtained from Portland cement, is its very slow setting speed (or hardening speed) resulting in poor mechanical performance in the early stages. A study has therefore been carried out to evaluate the performance of the ettringite binder according to the invention over shorter times, namely 3 days (D+3) or 7 days (D+7) after production of the mixture comprising: [0280] flash metakaolin ARGICEM® with IPZ between 700 and 800 mg/g; [0281] a slaked lime of type CL90 with LEDUC lime content of approximately 90%; and [0282] gypsum.

[0283] FIG. 2 is a graph showing the percentage increase in mechanical performance, after 3 days or after 7 days, for an ettringite binder obtained from the mixture according to the invention with respect to those of a conventional pozzolanic composition, as a function of the value of the parameter RMK.

[0284] The results show comparable results to those obtained after 28 days. Indeed, it is also observed that: [0285] for RMK values between 0.3 and 0.7, a gain greater than 40% is obtained compared to the performance of a conventional pozzolanic composition; and [0286] for values greater than 0.7, a strong decrease in the gain is observed.

[0287] In conclusion, these results show that the mixture according to the invention makes it possible to very quickly obtain an ettringite binder having good mechanical performance (compressive strength) even in very short times, times in which conventional pozzolan compositions are not able to deliver mechanical strengths that are acceptable for their use as construction materials.

Example 4: Preparation of a Material from an Ettringite Binder Comprising a Metakaolin/Lime/Gypsum Mixture in the Presence of a Catalyst and an Activator—Comparison of the RMK

[0288] The aim is to compare the performance of a material obtained from a binder according to the invention, for RMK values greater than 0.6.

[0289] To do this, a material was prepared by hydration of an ettringite binder comprising Argical M1000®/quarry calcium sulfate/lime CL90 in the presence of a catalyst and activator. The parameter Sat(CH) is 1.07-1.1. The water/binder ratio is approximately 0.53.

[0290] The compressive strength (RC) at 28 days has been measured for two RMK values:

TABLE-US-00002 RMK RC (MPa) 0.6 44 0.91 54

[0291] These results show that an increased gain is obtained for RMK values greater than 0.6 when the material is prepared from an ettringite binder comprising a catalyst and/or an activator.

Example 5: Preparation of a Material from an Ettringite Binder Comprising a Metakaolin/Lime/Gypsum Mixture in the Presence of a Catalyst and Performance of this Material

[0292] The aim of this experiment was to study the mechanical performance of an ettringite binder obtained from a metakaolin/lime/gypsum mixture with or without alkali catalyst.

[0293] The metakaolin/lime/gypsum mixture is characterised by an RMK value equal to 0.67 and an Sat(CH) value approximately equal to 1.03.

[0294] Various catalysts have been tested: sodium fluoride, sodium aluminate, trisodium phosphate, sodium orthosilicate and sodium metasilicate and sodium hexafluorate.

[0295] The compressive strength (RC) was measured 3 days (D+3) or 7 days (D+7) after the preparation of the mixture. The results are presented in Table 2 below.

TABLE-US-00003 TABLE 2 Compressive strength and percentage gain for the metakaolin/ gypsum/lime mixtures in the presence of a catalyst. D + 3 D + 7 RC* Gain RC* Gain Mixture (MPa) (%) (MPa) (%) Without catalyst 13.6 — 26.7 — Sodium fluoride 20.9 54 32.3 21 Sodium aluminate 20.5 51 29.9 12 Trisodium phosphate 25.8 90 29.5 11 Sodium orthosilicate 23.2 70 31.2 17 Sodium metasilicate 23.9 75 33.4 25 Sodium hexafluorosilicate 23.9 75 33.4 25 *RC: compressive strength.

[0296] A study has also been carried out by varying the type of gypsum and the values of the parameter RMK. The results obtained after 7 days (D+7) and 28 days (D+28) are presented in Table 3 below.

TABLE-US-00004 TABLE 3 Percentage gain for various metakaolin/gypsum/lime mixtures in the presence of a catalyst as a function of the parameter RMK and of the gypsum source, compared with the same mixture without catalyst. Quantity of catalyst in D + D + the mixture 7 28 Mixture with the (in kg/tonne Gain Gain catalyst: of binder) Gypsum RMK (%) (%) Sodium fluoride 10 Desulfogypsum 0.76 31 18 10 Desulfogypsum 0.45 17 11 10 Desulfogypsum 0.3 11 5 Sodium 20 Desulfogypsum 0.3 35 13 hexafluoroaluminate Fluorophosphate 20 Desulfogypsum 0.3 30 13 Sodium aluminate 3.3 Desulfogypsum 0.77 30 20 6.7 Desulfogypsum 0.77 42 20 13.3 Desulfogypsum 0.77 46 19 Sodium 4.1 Titanogypsum 0.66 18 4 hexametaphosphate 8.3 Titanogypsum 0.66 31 17 Sodium carbonate 4.1 Titanogypsum 0.66 21 17 Sodium borate 4.1 Titanogypsum 0.66 21 17 Sodium aluminate 8.3 Titanogypsum 0.66 36 15 13.1 Titanogypsum 0.66 50 29 13.3 Gypsum from 0.66 34 14 demolition 13.3 Gypsum from 0.43 31 34 demolition 26.7 Gypsum from 0.61 57 41 demolition *RC: compressive strength.

[0297] The results show that the addition of an alkali catalyst in the mixture increases the compressive strength at short times (D+7) or longer times (D+28).

Example 6: Preparation of a Material from an Ettringite Binder Comprising a Metakaolin/Lime/Gypsum Mixture in the Presence of a Catalyst and an Activator and Performance of this Material

[0298] The progress of the formation reaction of ettringite depends on the addition of calcium aluminate formed by the reaction between the aluminosilicate source and the calcium oxide source (lime). However the mechanical performance of the material obtained from the ettringite binder according to the invention depends on the yield from the reaction between the calcium aluminate and the calcium sulfate source (such as gypsum).

[0299] The Applicant has therefore sought to optimise the mixture according to the invention in order to provide better yields and higher compressive strengths

[0300] Various compounds have been tested on a mortar base. The formulation of the mortar consists of mixing sand, water and the ettringite binder according to the invention comprising a mixture of: [0301] flash metakaolin ARGICEM® with IPZ approximately equal to 700 mg/g; [0302] slaked lime of type CL90 with LEDUC lime content of approximately 90%; and [0303] desulfogypsum; and [0304] NaAlO.sub.2 (1.3%) as catalyst;
wherein [0305] the parameter RMK is equal to 0.82; [0306] the parameter Sat(CH) is equal to 1.03.

[0307] The mortar has a sand to binder ratio (L/T) equal to 0.33. The water to binder ratio (E/L) is between 0.47 and 0.55.

[0308] Surprisingly, the Applicant has shown that compounds able to complex calcium, such as sucrose and/or alpha hydroxy acids, make it possible to obtain improved compressive strengths after 7 and 28 days with respect to the reference formulation Ml (cf. Table 4).

TABLE-US-00005 TABLE 4 Performance of an ettringite binder comprising at least an activator Ref. M1 M2 M3 M4 M5 M6 M7 M8 M9 M10 M11 M12 M13 Tartaric acid — 1.3 1.3 1.3 1.3 — — — — 1.3 1.3 — — (kg/tonne of binder) Sucrose — 1.3 — 0.3 0.7 1.3 1.3 — — 0.7 0 1.3 1.3 (kg/tonne of binder) Others — Citric Gluconic Citric TEA TEA Salicylic Mandelic (kg/tonne acid acid acid (1.3) (1.3) acid acid of binder) (1.3) (1.3) (1.3) (1.3) (1.3) E/L 0.55 0.47 0.53 0.53 0.53 0.53 0.53 0.53 0.53 0.53 0.53 0.54 0.55 RC D + 7 (MPa) 29.2 39.5 34.7 33.1 39.2 36.1 31.4 36.2 37.2 35.8 35.6 32.3 33.1 % Gain — 35.3 18.8 13.4 34.2 23.6 7.5 24 27.4 22.6 21.9 10.6 13.4 RC D + 28 (MPa) 34.5 52.6 43.6 46.4 47.8 43.1 45.8 42.4 46.8 48.8 45.6 38.7 38.7 % Gain — 52.5 26.4 34.5 38.6 24.9 32.8 22.9 35.7 41.4 32.2 12.2 12.2

Part B: Uses of the Ettringite Binder for Producing Construction Materials

Example 7: Preparing Cement

[0309] The Applicant has prepared a plurality of cements from the ettringite binder according to the invention. The ratio of water to binder (E/L) is 0.5. The formulations and results are presented in Table 5 below.

[0310] The flexural strength and compressive strength have been measured using samples of 4×4×16 mm. The results show that the performance of these cements conforms with the compressive strength values required by standard EN-196.

TABLE-US-00006 TABLE 5 Performance of cements prepared from the ettringite binder according to the invention. Compound (in kg for 1 tonne of binder) Cement 1 Cement 2 Cement 3 Cement 4 Cement 5 Binder Metakaolin 575 550 492 452 452 formulation Argicem ® Lime CL90 290 280 246 226 226 Dry gypsum 95 162 246 226 226 BF slag 0 0 0 65.8 65.8 Fillers 40 0 0 0 0 Catalyst 0 NaF: 8 NaAlO.sub.2: 13.4 MSLK: 19.4 NaHFS: 19.4 Sucrose 0 0 1.3 1.1 1.1 Tartaric acid 0 0 1.3 1.1 1.1 Parameters RMK 0.26 0.48 0.82 0.82 0.82 Sat(CH) 1.04 1.05 1.03 1.03 1.03 Performance at Flexing 4.9 6.7 6.9 7.9 7.9 28 days (MPa) Compression 33.7 36.4 44.1 47.6 47.6

Example 8: Road Binder Preparation

[0311] The Applicant has prepared a plurality of road binders from the ettringite binder according to the invention.

[0312] The objective is to provide a road binder able to meet the mechanical strength objectives fixed by standard NF P15-108, namely obtaining a load-bearing value (module EV2) greater than 50 MPa.

[0313] The determination of the load bearing is carried out using the “load plate test”. This method involves applying a stress on a surface of normalised diameter and rigidity in order to measure its depression in the ground. This method enables determination of the Westergraad reaction coefficient (Kw), the load-bearing moduli EV1 and EV2 and the compaction ratio (EV2/EV1).

[0314] The studied binder according to the invention comprises a mixture of: [0315] 600 kg/tonne of binder, flash metakaolin ARGICEM® with IPZ approximately equal to 700 mg/g; [0316] 300 kg/tonne of binder, slaked lime of type CL90 with LEDUC lime content of approximately 90%; and [0317] 100 kg/tonne of binder, gypsum;
wherein [0318] the parameter RMK is equal to 0.27; [0319] the parameter Sat(CH) is equal to 1.03.

[0320] For this purpose, a clay/sand soil with an area of 250 m.sup.2 and with depth of 40 cm, was mechanically stabilised with the binder according to the invention. The dosage of binder was between 35 and 40 kg per square metre. After 28 days, the load bearing capacity EV2 was measured on this stabilised soil. The results are presented in Table 6.

TABLE-US-00007 TABLE 6 Properties from the load plate test obtained using the binder according to the invention. Compaction ratio Kw EV1 (MPa) EV2 (MPa) EV2/EV1 55 40 74 1.8 58 39 79 2.0

[0321] The results show that the EV2 moduli are greater than 50 MPa.

[0322] Consequently, these results confirm that the binder according to the invention can be used as a road binder while meeting the requirements of standard NF P15-108.

Example 9: Mortar Preparation

[0323] The Applicant has prepared a plurality of mortars from the ettringite binder according to the invention.

[0324] Table 7 shows some examples of mortars prepared by the applicant by using the binder according to the invention. In this table, the quantities are expressed in kg per tonne of binder

[0325] These mortars have been used as rendering mortars on various supports such as concrete or plaster, or as mortars for mounting on breeze block, hollow brick, biobrick and natural stone substrates. After 8 months of observation, no incompatibility was visually observed.

TABLE-US-00008 TABLE 7 Formulations and properties of mortars obtained from an ettringite binder according to the invention. MRT1 MRT2 MRT3 MRT4 MRT5 MRT6 MRT7 Formulation MK Type Argicem ® Argicem ® Argicem ® Argicem ® M1000 ® Argicem ® Argicem ® Quantity 150 150 105 160 140 130 130 Lime Type CL90 CL90 CL90 CL90 CL90 CL90 CL80 Quantity 75 75 53 80 90 65 80 Gypsum Type Quarry Quarry Quarry Desulfo- Quarry Desulfo- Gypsum gypsum gypsum gypsum gypsum gypsum gypsum from demolition Quantity 75 75 18 45 55 65 90 Catalyst Type NaAlO.sub.2 NaAlO.sub.2 — NaF NaF NaF NaAlO.sub.2 Quantity 4 4 — 3 3 4 6 Accelerator Tartaric acid 0.4 0.4 0 0 0 0.35 0.4 Accelerator Sucrose 0.4 0.4 0 0 0 0.35 0.4 Blast furnace slag 0 0 0 15 15 40 0 Additives SP* Type V225 V225 V225 V150 V150 V225 V430 Quantity 0.9 0.9 1 1 0.9 0.9 0.9 Aggregates Fillcarb ® 0 20 124 20 20 20 0 Sand 0/1 0 100 0 100 100 100 0 Sand 0/1 900 480 900 480 480 480 900 Water 125 120 138 114 161 115 150 Parameters RMK 0.82 0.82 0.28 0.46 0.45 0.82 0.91 Sat(CH) 1.03 1.03 1.03 1.03 0.93 1.03 1.12 Performance RC (MPa) D + 7 21.9 31.5 9.6 42.6 32.1 39.7 30.1 D + 28 44.6 51.5 16.8 45.9 38.7 50.3 43.6 Terracotta adhesion (MPa) 0.58 1.32 NA NA NA NA NA *superplasticiser

Example 10: Concrete Preparation

[0326] The Applicant has prepared a plurality of concretes from the ettringite binder according to the invention.

[0327] Table 8 shows some examples of concretes prepared by the Applicant be using the binder according to the invention. In this table, the quantities are expressed in kg per tonne of binder

TABLE-US-00009 TABLE 8 Concrete formulations obtained from the binder according to the invention. Compound B1 B2 B3 B4 Formulation Metakaolin Argicem ® 30 22 50 40 Lime CL90 15 11 25 20 Gypsum 15 11 11 20 Sodium aluminate 0.80 0.60 0 1.07 Sucrose 0.80 0.60 0 0.11 Tartaric acid 0.80 0.60 0 0.11 Fill Carb ® 0 0 2 2 Sand 0/1 0 55 17 17 Sand 0/4 105 44 85 85 Sand 4/10 84 121 84 84 Water 28 21 40 35 RC at 28 Cubes 10 × 10 25.8 35.1 NA NA days (MPa) Cylinders 16 × 32 20.7 27.9 25.8 40.1 Strength class (by sclerometer) (MPa) 20-30 40-50 25-35 40-50

Example 11: Preparation of Masonry Cement and Formulated Limes

[0328] The Applicant has prepared a plurality of masonry cements and formulated limes from the ettringite binder according to the invention.

[0329] In order to be used as masonry cement or formulated lime, the formulation must have a compressive strength after 28 days of at least 10 MPa for masonry cements and at least 3.5 MPa in the case of formulated limes.

[0330] Table 9 shows some examples of masonry cements prepared by the applicant using the binder according to the invention. In this table, the quantities are expressed in kg per tonne of binder

TABLE-US-00010 TABLE 9 Masonry cement and formulated lime formulations obtained from the binder according to the invention. Formulation CM1 CM2 CM3 CM4 CM5 CM6 Metakaolin Argicem ® Argicem ® Argicem ® Argicem ® Argicem ® Argicem ® Metakaolin (qty) 270 268 332 332 333 332 Lime CL90 135 134 332 400 333 266 Gypsum 95 95 166 100 167 166 Calcareous filler 500 500 167 165 167 233 Catalyst (fluoride) 0 3 3 3 0 3 RMK 0.58 0.58 0.82 0.49 0.57 0.57 RC (D + 3) 5.7 7.2 10.2 9.8 11.6 11 RC (D + 7) 9 14.6 15.8 13.9 23.4 23.9 RC (D + 28) 15.2 20.5 22.3 16.8 34.3 32.6

[0331] The results show that from three days, excellent results are obtained for the formulations comprising the ettringite binder according to the invention.