Method for analyzing the quantity of clay in a sand

The present invention relates to a method for analyzing the amount of clay in a sand. This method makes it possible in particular to anticipate the overconsumption of superplasticizer due to the presence of clays and thus to act accordingly.

The presence of sodium clays, such as Montmorillonite, in sands or in aggregates can strongly affect the workability of hydraulic binder compositions, in particular concrete compositions. In fact, the layered structure of the clays promotes the absorption of water and the intercalation of the elements contained in the hydraulic binder compositions, such as, for example, superplasticizers and in particular those carrying poly (alkylene glycol) grafts. These phenomena cause an increase in the viscosity of the hydraulic binder paste, and therefore a loss of workability. An overdose of superplasticizer is then necessary to compensate for its consumption by the clays and to maintain the desired workability. This phenomenon is not observed for calcic clays.

The quantity of clay is generally determined by the methylene blue test (Standard NF EN 933-9). However, this analysis is not selective for the potentially problematic clays and moreover it is sensitive to the amount of fine sand.

There is therefore an interest in proposing an analysis protocol for the quantification of the rate of superplasticizer-consuming clays in sands allowing in particular the prediction of a dosage of Clay Activity Modifying Agent (AMAA).

An objective of the present invention is therefore to provide an analysis method for quantifying the level of superplasticizer-consuming clays.

Another objective of the present invention is to provide such a method allowing the prediction of an AMAA assay.

Yet another objective of the present invention is to provide such a method which is simple and can be used in the field.

Still other objectives will become apparent on reading the description of the invention which follows.

All these objectives are fulfilled by the present invention which relates to the use of compound of formula (I) for analyzing and determining the quantity of clay in a sand, in particular for determining by colorimetry the quantity of clay in a sand,

R 1 - (OA) n -XR 2 (I)

in which

R 1 represents a C1 to C4 alkyl group, linear or branched, or a colored compound;

R 2 represents a colored compound;

A, each the same or different, independently represents a -CH2-CH2- group or an -OH (OH 3 ) -OH - group;

n represents an integer between 1 and 500, preferably between 4 and 250 X is O or NH.

In the context of the present invention, the term “colored compound” is intended to mean any type of compound exhibiting adsorption of radiation whose wavelengths belong to the visible range. It should be understood that when R 2 and optionally R 1 represents a colored compound, it is a residue of a colored compound following the reaction of a colored compound with the XH function. Preferably, the colored compounds of the invention exhibit a function allowing their reaction with the XH function thus leading to a residue of the colored compound, preferably this function is the COOH function neutralized or not.

Preferably, for the compounds of formula (I) according to the invention, R 1 represents a methyl, ethyl, propyl or butyl group, preferably methyl.

Preferably, for the compounds of formula (I) according to the invention, A represents a -CH2-CH2- group.

Preferably, for the compounds of formula (I) X is O or N, preferably O.

Preferably, for the compounds of formula (I) n represents an integer between 1 and 500.

Preferably, for the compounds of formula (I) according to the invention:

R 1 represents a methyl, ethyl, propyl or butyl group; and or

A represents a group -CH2-CH2-, -OH (OH 3 ) -OH -; and or

X is O or N, preferably O; and or

n represents an integer between 1 and 500, preferably between 4 and 250.

Preferably, for the compounds of formula (I) according to the invention:

R 1 represents a methyl group;

A represents a -CH2-CH2- group;

X is O; and

n represents an integer between 4 and 250.

Preferably, in the compounds of formula (I), the colored compound is chosen from the following groups:

- Azobenzene derivatives having a neutralized COOH function or not reacting with the XH function;

- Acridine derivatives having a COOH function neutralized or not reacting with the XH function;

- Anthraquinone derivatives having a COOH function neutralized or not reacting with the XH function;

- Phthalocyanine derivatives having a neutralized COOH function or not reacting with the XH function;

- Quinone derivatives having a COOH function neutralized or not reacting with the XH function;

- Indophenol derivatives having a neutralized COOH function or not reacting with the XH function;

- Oxazone derivatives having a neutralized COOH function or not reacting with the XH function;

- Thiazine derivatives having a neutralized COOH function or not reacting with the XH function;

- Xanthene derivatives having a COOH function neutralized or not reacting with the XH function;

- Fluorone derivatives having a neutralized COOH function or not reacting with the XH function.

By derivatives is meant, in the context of the present invention, compounds comprising the functions mentioned above.

Preferably, in the compounds of formula (I), the colored compound is chosen from the following groups:

- Azobenzene derivatives having a neutralized COOH function or not reacting with the XH function;

- Xanthene derivatives having a neutralized COOH function or not reacting with the XH function.

Preferably, the colored compound is chosen from:

- Azobenzene derivatives having a neutralized COOH function or not reacting with the XH function;

- Rhodamine derivatives having a COOH function neutralized or not reacting with the XH function;

- Fluorescein derivatives having a neutralized COOH function or not reacting with the XH function.

Preferably, the colored compound is chosen from:

- Azobenzene derivatives having a neutralized COOH function or not reacting with the XH function;

- Rhodamine derivatives having a neutralized COOH function or not reacting with the XH function.

Preferably, the colored compound R 2 and optionally R 1 is chosen from the compounds of the following formula:

Preferably, the colored compound R 2 and optionally R 1 is chosen from the compounds of the following formula:

Particularly advantageously, the inventors have shown that the compounds of formula (I) according to the invention are intercalated in the layers of the clays. This intercalation of the compounds of formula (I) results in a decrease in the intensity of the color of the colored compound. This decrease in the intensity of the color of the colored compound makes it possible to determine the quantity of compounds of formula (I) intercalated, which makes it possible to determine the quantity of clay in the sand.

In a particularly advantageous manner, the compounds of formula (I) according to the invention make it possible specifically to determine the quantity of clays which are harmful to the superplasticizers, that is to say the quantity of clays intercalating the superplasticizers. Particularly advantageously, the compounds of formula (I) of the invention will not intercalate in the clays which do not intercalate the superplasticizers. Thus, the compounds of formula (I) and the processes used are very specific for clays which intercalate the superplasticizers.

The compounds of formula (I) can be prepared by a preparation process comprising the reaction between a compound of formula (II) and a colored compound comprising at least one function reactive with the XH group of the compound of formula (II)

Y- (OA) n -XH (II)

in which

Y represents H or an alkyl group, linear or branched, C1 to C4;

A, X and n are as defined for the compounds of formula (I).

The process of the present invention can be carried out at a temperature between 40 ° C and 200 ° C, preferably between 100 ° C and 185 ° C.

The colored compounds are chosen from the following compounds:

- Azobenzene derivatives having a neutralized COOH function or not reacting with the XH function;

- Acridine derivatives having a COOH function neutralized or not reacting with the XH function;

- Anthraquinone derivatives having a COOH function neutralized or not reacting with the XH function;

- Phthalocyanine derivatives having a neutralized COOH function or not reacting with the XH function;

- Quinone derivatives having a COOH function neutralized or not reacting with the XH function;

- Indophenol derivatives having a neutralized COOH function or not reacting with the XH function;

- Oxazone derivatives having a neutralized COOH function or not reacting with the XH function;

- Thiazine derivatives having a neutralized COOH function or not reacting with the XH function;

- Xanthene derivatives having a COOH function neutralized or not reacting with the XH function;

- Fluorone derivatives having a neutralized COOH function or not reacting with the XH function.

By derivatives is meant, in the context of the present invention, compounds comprising the functions mentioned above.

Preferably, in the compounds of formula (I), the colored compound is chosen from the following groups:

- Azobenzene derivatives having a neutralized COOH function or not reacting with the XH function;

- Xanthene derivatives having a neutralized COOH function or not reacting with the XH function.

Preferably, the colored compound is chosen from:

- Azobenzene derivatives having a neutralized COOH function or not reacting with the XH function;

- Rhodamine derivatives having a neutralized COOH function or not reacting with the XH function.

Preferably, the colored compound is chosen from:

- Azobenzene derivatives having a neutralized COOH function or not reacting with the XH function;

- Rhodamine derivatives having a COOH function neutralized or not reacting with the XH function;

- Fluorescein derivatives having a neutralized COOH function or not reacting with the XH function.

Preferably, the colored indicator compound is chosen from the following compounds:

Preferably, the colored indicator compound is chosen from the following compounds:

Preferably, the colored compounds are the following compounds:

Preferably, in the compound of formula (II) X is O.

Preferably, in the compound of formula (II) Y is methyl, ethyl, propyl or butyl, preferably methyl.

Preferably, in the compound of formula (II) A is -CH2-CH2-.

Preferably, in the compound of formula (II) n represents an integer between 1 and 500, preferably between 4 and 250.

Preferably, for the compounds of formula (II) according to the invention:

R 1 represents a methyl, ethyl, propyl or butyl group, preferably methyl; and / or A represents a -CH2-CH2- group; and or

X is O; and or

n represents an integer between 1 and 500, preferably 4 and 250.

Preferably, for the compounds of formula (II) according to the invention:

R 1 represents a methyl group;

A represents a -CH2-CH2- group;

X is O;

n represents an integer between 4 and 250.

Preferably, in the process of the invention, the molar ratio of compound of formula colored compound / formula (II) is between 2 and 1, preferably 1.

The present invention also relates to a composition (C) comprising a compound of formula (I) and its use for analyzing and determining the quantity of clay in a sand, in particular for determining by colorimetry the quantity of clay in a sand.

The composition of the invention may also comprise a pH buffer solution so that the composition is at a pH at which the compound of formula (I) exhibits adsorption of radiation, the wavelengths of which belong to the visible range. Those skilled in the art are able to determine the pH buffer to be used and the target pH, the objective being for composition (C) to be of the desired color. For example, when the colored compound is the following compound:

the pH of composition (C) is between 4 and 5.5, in particular by using a pH buffer, for example chosen from the group consisting of acetic acid / sodium acetate / potassium; sodium / potassium dihydrogenphosphate / hydrogenphosphate, di-sodium / di-potassium; sodium and / or potassium dihydrogenphosphate.

Preferably, composition (C) of the invention is an aqueous composition comprising from 0.01 to 0.1% by weight of compound of formula (I).

The inventors have advantageously shown that the compounds of the invention can be used to determine the quantity of clay in a sand.

This is particularly important for estimating the future consumption of plasticizer or superplasticizer, or even estimating the dosage of any composition intended to compensate for the negative effect of clays in a concrete composition. As indicated above, the compounds of formula (I) according to the invention are intercalated in the clay layers, like superplasticizer or plasticizer molecules. This intercalation of the compounds of formula (I) results in a decrease in the intensity of the color of the colored compound. This reduction in the intensity of the color of the colored compound makes it possible to determine the quantity of compounds of formula (I) intercalated and therefore consumed by the sand. It is then possible to determine the amount of clays present in the sand.

AMAA to be added to reduce or even eliminate the harmful effects of clays on maintaining workability.

Preferably, AMAAs are described in patent application EP1015398.

AMAA can also, for example, be a compound from the CHRYSO®Quad range, preferably CHRYSO®Quad 800.

The present invention also relates to the use of a compound of formula (I) or of a composition (C) according to the invention to determine the amount of AMAA compound to be added to a hydraulic binder composition, in particular to reduce or even eliminate the harmful effects of clays present in the sand on the maintenance of workability.

The present invention also relates to the compounds of formula (I) described above and to the compositions (C) as such.

Thus, the present invention relates to a method for determining the amount of agile in a sand comprising the following steps:

a) Provide a composition (C) according to the invention;

b) Take a sample of the sand to be analyzed;

c) Mix composition (C) with the sand sample in a container and stir; d) Filter the mixture obtained in step c);

e) Determine, as a function of the color of the solution obtained in step d), the concentration of clays in the sand.

It should be understood that the method according to the invention makes it possible to determine the quantity of clay having an impact on the workability of the hydraulic binder compositions, in particular clays involving an intercalation of superplasticizer in the sheets. Thus preferably, the method according to the invention allows the determination of the amount of phyllosilicate clay in a sand, preferably montmorillonites, even more preferably sodium montmorillonites.

In one embodiment, step e) can be carried out by visually determining the color and correlating this color to a range of quantity of clays.

In another embodiment, step e) can be carried out by photometric measurement of the color. In this case, step e) comprises a step e1) of photochemical measurement of the absorbance of the filtrate obtained in step d) and a step e2) of subtraction of the value obtained in step e) from the photochemical measurement absorbance

of composition (C) and plotting the value on a calibration curve to determine the percentage by weight of clay in the sand. The method according to the present invention can therefore also comprise a preliminary step aO) of photometric measurement of the absorbance of the composition (C).

Preferably, the stirring of step c) is carried out manually by inverting the container in which the mixture is located, for example by inverting the container at least 60 times, for example 100 times.

The photometric measurement of the absorbance of composition (C) and of the filtrate obtained in step d) can be carried out by any method known to those skilled in the art and by any material having a wavelength compatible with the compound. colored indicator of the compound of formula (I). For example, this measurement is carried out with a colorimeter, for example with a laser wavelength of between 400 and 700 nm, preferably between 475 and 600 nm.

In the case where, the colored compound is of formula:

the measurement is preferably carried out with a colorimeter having a laser wavelength of between 400 and 700 nm, preferably between 475 and 600 nm.

Before any photometric measurement of the absorbance, the method according to the invention can advantageously comprise the photometric measurement of the absorbance of a blank. The blank can be water or, if composition (C) comprises a buffer solution, the blank can be produced with this buffer solution. The production of a blank makes it possible to dispense with any variation in measurement linked to any element external to the mixture to be analyzed, for example a container comprising the mixture to be analyzed.

Step d) of filtering the mixture obtained in step c) can be carried out in any manner known to those skilled in the art. Preferably, the mixture, at the end of step c) is left to settle, preferably between 1 and 60 minutes, preferably between 1 and 30 minutes. This decantation step advantageously allows the finest particles to fall back to the bottom of the container and avoid clogging the filter. The supernatant is then taken with any suitable material, for example with a syringe, then filtered, from

preferably on a filter with a porosity of between 0.25 and 5 μm, preferably between 0.25 and 2 μm. Preferably, the amount of filtrate to be taken in order to carry out the photometric measurement depends on the device used and can be determined by a person skilled in the art, for example the volume is at least 10 ml.

Preferably, the sample of sand taken corresponds to a mass of between 10 and 100 g. Preferably, the amount of composition (C) added to the sand sample is at least 25 ml, preferably between 25 and 100 ml.

The method of the invention can also comprise a step of adjusting the pH before step e) in order to be in the range of pH values ​​making it possible to see the color of the colored compound.

In order to determine the amount of clay contained in the sand sample, a calibration curve should be made. This calibration curve can be produced by any method known to those skilled in the art.

In particular, the calibration curve can be obtained for example:

- by photometric measurement or visual detection of the change in color of a sand free of agiles (for example pure AFNOR sand) and of a sand free of agiles with the addition of various known quantities of clays;

- by measuring the total organic carbon (TOC) of a sand free of clays (for example pure AFNOR sand) and of a sand free of agiles with the addition of various known quantities of clays;

- by measuring the total organic carbon (TOC) of a sand free of clays (for example pure AFNOR sand) and of sands comprising clays.

Without wishing to be bound by any theory, the consumption of poly (alkylene) glycol by the clays, in particular Montmorillonite is determined by the difference between the amount of poly (alkylene) glycol in solution before introduction of the sand into the poly (alkylene) solution glycol and after 5 min of contact between the sand and this solution. The TOC content in the filtrate of a sand suspension without poly (alkylene) glycol is also measured and serves as a blank for TOC measurements.

The TOC measurement is carried out on the initial solutions and the filtrates with the SHIMADZU TOC-VCPN analyzer. The TOC is calculated by the difference between the amount of total carbon (obtained by carbonization of the solution and measurement of the amount of C0 2 released in infrared) and the amount of inorganic carbon (obtained by acidification of the solution to pH <1 and release of C0 2dissolved by bubbling in synthetic air). The amount of poly (alkylene) glycol consumed is calculated by the difference between what was introduced into the initial solution and what is measured in the filtrates. In the context of the present invention, the TOC measurements are carried out after filtration of the supernatant resulting from bringing the sand into contact with the solution of composition (C) according to the invention.

The calibration curve making it possible to carry out step e) according to the invention can be obtained as follows:

- A known amount of composition (C) according to the invention is added to a known amount of clay-free sand (for example pure AFNOR sand), mixed, filtered (mixing and filtration may preferably be identical to steps c) and d) mentioned above) and looking at the color of the filtrate obtained;

- A known quantity of composition (C) according to the invention is added to various mixtures comprising a known quantity of sand free of clays (for example pure AFNOR sand) and a known quantity of clays, one mixes, one filters (the mixing and filtration can preferably be identical to steps c) and d) mentioned above) and we look at the different colors of the filtrates obtained;

- A color gradient is determined corresponding to different ranges of clay concentration in the sand.

The calibration curve making it possible to carry out step e) according to the invention can also be obtained as follows:

- A photometric measurement of the composition (C) according to the invention is carried out;

- A known amount of composition (C) according to the invention is added to a known amount of clay-free sand (for example pure AFNOR sand), mixed, filtered (mixing and filtration may preferably be identical to steps c) and d) mentioned above) and a photometric measurement of the filtrate obtained is carried out from which the value of the photometric measurement of composition (C) is deduced;

- A known quantity of composition (C) according to the invention is added to various mixtures comprising a known quantity of sand free of clays (for example pure AFNOR sand) and a known quantity of clays, one mixes, one filters (the mixing and filtration can preferably be identical to steps c) and d) mentioned above) and a photometric measurement is carried out of the filtrates obtained from which the value of the photometric measurement of composition (C) is deduced;

- The absorbance curve is determined as a function of the concentration of clays in the sand.

The calibration curve making it possible to carry out step e) according to the invention can also be obtained as follows:

- A photometric measurement of the composition (C) according to the invention is carried out;

- Measuring the TOC of a known quantity of clay-free sand (for example pure AFNOR sand);

- A known amount of composition (C) according to the invention is added to a known amount of clay-free sand (for example pure AFNOR sand), mixed, filtered (mixing and filtration may preferably be identical to steps c) and d) mentioned above) and a photometric measurement of the filtrate obtained is carried out from which the value of the photometric measurement of the composition (C) is deduced, the TOC value is linked with the photometric value which allows to have an absorbance value for a sand free of clays;

- we measure the TOC of a known quantity of at least two commercial sands (for example Osman sand, Signes sand, St Marthe sand, Lecieux sand, Fulchiron sand, Vernou sand, Vesseny sand, Goutrens sand, Bernières sand, Inerti sand Salinello, Siegwart sand, TRK sand, Sail s / s Couzan sand);

- A known amount of composition (C) according to the invention is added to at least two commercial sands (for example Osman sand, Signes sand, St Marthe sand, Lecieux sand, Fulchiron sand, Vernou sand, Vesseny sand, Goutrens sand, sand Bernières, Inerti Salinello sand, Siegwart sand, TRK sand, Sail s / s Couzan sand) are mixed, filtered (the mixture and the filtration can preferably be identical to steps c) and d) mentioned above) and we carry out a photometric measurement of the various filtrates obtained from which the value of the photometric measurement of the composition (C) is deduced, the TOC value is linked with the photometric value obtained which makes it possible to have an absorbance value for a clay concentration known ;

- The absorbance curve is determined as a function of the concentration of clays in the sand.

The relationship between the TOC value (MPEG consumed) and the clay concentration (Eq Mnt) is as follows:

m MPEG consumed +

EqMnt

1.1943
The calibration curve making it possible to carry out step e) according to the invention can also be obtained as follows:

- Measuring the TOC of a known quantity of clay-free sand (for example pure AFNOR sand);

- A known amount of composition (C) according to the invention is added to a known amount of clay-free sand (for example pure AFNOR sand), mixed, filtered (mixing and filtration can preferably be identical to steps c) and d) mentioned above) and we look at the color of the filtrate obtained, which makes it possible to have the color of a sand free of clays;

- we measure the TOC of a known quantity of at least two commercial sands (for example Osman sand, Signes sand, St Marthe sand, Lecieux sand, Fulchiron sand, Vernou sand, Vesseny sand, Goutrens sand, Bernières sand, Inerti sand Salinello, Siegwart sand, TRK sand, Sail s / s Couzan sand);

- A known amount of composition (C) according to the invention is added to at least two commercial sands (for example Osman sand, Signes sand, St Marthe sand, Lecieux sand, Fulchiron sand, Vernou sand, Vesseny sand, Goutrens sand, sand Bernières, Inerti Salinello sand, Siegwart sand, TRK sand, Sail s / s Couzan sand) we mix, we filter (the mixing and the filtration can preferably be identical to steps c) and d) mentioned above) and we look at the color of the filtrates obtained, the TOC value is linked with the color range obtained, which makes it possible to have a color gradient as a function of the clay concentration range.

The present invention advantageously makes it possible to provide the dosage of AMAA compound to be used to limit or even eliminate the harmful effect of clays, in particular on reducing water and maintaining workability. For this, it is necessary to construct a correlation curve making it possible to link the necessary assay in AMAA as a function of the color or of the absorbance (photometric measurement) obtained in step e).

This correlation curve can be obtained by determining the amount of AMAA to use as a function of the clay concentration in the sand, the relationship between the clay concentration in the sand and the color or absorbance (photometric measurement) obtained at step e) being detailed above.

The correlation curve between the amount of AMAA to use as a function of the clay concentration in the sand can be produced as follows:

- The spreading at 5 minutes (T5) and the maintenance of a reference mortar obtained with AFNOR sand are measured;

- the spreading at 5 minutes (T5) and the maintenance of at least two mortars obtained with different commercial sands (for example Osman sand, Signes sand, St Marthe sand, Lecieux sand, Fulchiron sand, Vernou sand, sand Vesseny, Goutrens sand, Bernières sand, Inerti Salinello sand, Siegwart sand, TRK sand, Sail s / s Couzan sand);

- AMAA is added to the mortars obtained with different commercial sands so as to obtain a spread at 5 minutes (T5) and a hold similar to that obtained for the reference mortar;

- The curve of the quantity of AMAA to be added is deduced therefrom as a function of the concentration of clays in the sand.

It is then possible with the calibration curves described above to determine the curve of the amount of AMAA as a function of the color or absorbance value (photometric measurement) obtained in step e). This curve is preferably constructed as a function of the hydraulic binder used in the mortar.

The spread can in particular be evaluated as follows:

A mold without bottom of frustoconical shape, reproduction on a scale of 0.5 of the Abrams cone (see standard NF 18-451, 1981) with the following dimensions: diameter of the upper circle = 5cm, diameter of the circle of the lower base = 10 cm, height 15 cm. After mixing the mortar containing the polymer, the mold is filled and the upper surface of the cone is leveled. The cone is lifted vertically and the spread is measured at 90 ° with a tape measure.

It is possible to adjust the pH of the filtrates before reading the color (by eye or by spectrometry) in order to be in the range of pH value making it possible to see the color of the colored compound.

Before any photometric measurement of the absorbance, it is advisable to carry out the photometric measurement of the absorbance of a blank. The blank can be water or the buffer solution used in composition (C). The production of a blank makes it possible to dispense with any variation in measurement linked to any element external to the mixture to be analyzed, for example a container comprising the mixture to be analyzed.

The present invention also relates to a kit for implementing the method according to the invention, comprising:

- A container provided with a stopper comprising the composition (C) according to the invention;

- A container for the determination of the sand sample;

- A means of taking liquid;

- A means of filtration;

- A receptacle for collecting the filtrate;

- A calibration curve making it possible to relate the color to the clay concentration of the sand and / or a correlation curve making it possible to relate the color to the quantity of AMAA to be used.

Preferably, the receptacle for collecting the filtrate is a transparent receptacle allowing the color of the filtrate to be seen. Preferably, the receptacle for collecting the filtrate is suitable for the photometric analysis of the absorbance.

Preferably the sample of sand is poured into the receptacle provided with a stopper comprising the composition (C) according to the invention.

Preferably, the liquid collection means is a syringe.

Preferably, the filtration means is a syringe filter having a porosity size preferably between 0.25 and 5 µm, preferably between 0.25 and 2 µm.

Preferably, the kit according to the invention comprises an apparatus for photometric measurement of the absorbance. Preferably, the apparatus allowing the photometric measurement of the absorbance is a colorimetry apparatus having a laser wavelength of between 400 and 700 nm, preferably between 475 and 600 nm.

The kit according to the invention can also comprise an acid or base solution which advantageously makes it possible to adjust the pH so as to be in the range of pH value making it possible to see the color of the colored compound.

The present invention also relates to a method for determining the amount of AMAA to be added to a sand for its use in a hydraulic binder composition comprising the following steps:

- Implementation of the method for analyzing the quantity of clay in a sand according to the invention;

- Construct a correlation curve making it possible to relate the clay concentration of a sand to the quantity of AMAA to be used to neutralize the clay, for example as described above;

- Plot the value obtained by implementing the method for analyzing the quantity of agile in a sand according to the invention on the equivalence curve.

The present invention also relates to a method for determining the amount of AMAA to be added to a sand for its use in a hydraulic binder composition comprising the following steps:

i) Provide a composition (C) according to the invention;

ii) Take a sample of the sand to be analyzed;

iii) Mix composition (C) with the sand sample in a container and stir; iv) Filter the mixture obtained in step iii);

v) Determine, as a function of the color of the solution obtained in step iv), the amount of AMAA to add.

Step ii), iii) and iv) can be carried out identically to steps b), c) and d) described above.

Step v) can be carried out identically to step e) described above, the correlation curves between the absorbance value and the amount of AMAA to be added can be carried out as described above.

Preferably, the present invention relates to a compound of formula (I)

R 1 - (OA) n -XR 2 (I)

in which

R 1 represents a linear or branched C1 to C4 alkyl group, or an azobenzene derivative having a COOH function neutralized or unreacting with the XH function;

R 2 represents an azobenzene derivative having a COOH function neutralized or not reacting with the XH function;

A, each the same or different, independently represents a -CH2-CH2- group or an -OH (OH 3 ) -OH - group;

n represents an integer between 1 and 500, preferably between 4 and 250 X is O or NH.

Preferably, R 1 represents a linear or branched C1 to C4 alkyl group, and R 2 represents:

The present invention will now be described with the aid of non-limiting examples. [Fig 1] FIG. 1 represents the correlation curve between the AMAA concentration to be used and the absorbance value measured for composition (C1) of Example 1.

[Fig 2] FIG. 2 represents the correlation curve between the AMAA concentration to be used and the absorbance value measured for the composition (C2) of Example 2.

Example 1: Synthesis of a composition (C1) according to the invention

In a two-necked flask fitted with a Dean Stark, 8.08 g of compound A, 140.80 g of MPEG 5000 and 1.13 g of sodium hydroxide solution (50% dry extract) are added and then stirred. The reaction medium is brought to 165 ° C. under a vacuum of 20 mbar. Under these conditions, the reaction medium is stored for 6 h. The temperature is lowered to room temperature then the reaction medium is diluted with a buffer (acetic acid / 0.1 M sodium acetate) to obtain the desired dry extract (0.04% by mass).

Compound A:

Example 2: Synthesis of a composition (C2) according to the invention

In a two-necked flask fitted with a Dean Stark, 3.04 g of compound B, 31, 71 g of MPEG 5000 and 0.25 g of sodium hydroxide solution (50% dry extract) are added and then stirred. The reaction medium is brought to 165 ° C. under a vacuum of 20 mbar. Under these conditions, the reaction medium is stored for 6 h. The temperature is lowered to room temperature then the reaction medium is diluted to obtain the desired dry extract (0.1% by mass).

Compound B:

Example 3: Synthesis of a composition (C3) according to the invention

In a two-necked flask fitted with a Dean Stark, 7.60 g of compound C, 141.27 g of MPEG 5000 and 1.13 g of sodium hydroxide solution (50% dry extract) are added and then stirred. The reaction medium is brought to 165 ° C. under a vacuum of 20 mbar. Under these conditions, the reaction medium is stored for 6 h. The temperature is lowered to room temperature then the reaction medium is diluted to obtain the desired dry extract (0.04% by mass).

Compound C:

Example 4: Realization of a straight line connecting the clay concentration to the TOC value

The consumption of MPEG5000 by clays, in particular Montmorillonite, is determined by the difference between the quantity of MPEG 5000 in solution before introduction of the sand into the polymer solution and after 5 min of contact between the sand and this solution. The TOC content in the filtrate of a sand suspension without polymers is also measured and serves as a blank for TOC measurements.

The TOC measurement is carried out on the initial solutions and the filtrates with the SHIMADZU TOC-VCPN analyzer. The TOC is calculated by the difference between the amount of total carbon (obtained by carbonization of the solution and measurement of the amount of C0 2 released in infrared) and the amount of inorganic carbon (obtained by acidification of the solution to pH <1 and release of C0 2 dissolved by bubbling in synthetic air). The amount of MPEG5000 consumed is calculated by the difference between what was introduced into the initial solution and what is measured in the filtrates.

The consumption of MPEG 5000 was measured on different sands collected in the field for initial dosages 0.4. The montmorillonite equivalent (EqMnt) is calculated from the following equation:

EqMnt m MPEG coTisominated ¾ 3e48 < |
1.1943 '

The sands collected on the ground are as follows: Osman sand, Signes sand, St Marthe sand, Lecieux sand, Fulchiron sand, Vernou sand, Vesseny sand, Goutrens sand, Bernières sand, Inerti Salinello sand, Siegwart sand, TRK sand, Sail sand s / s Couzan This makes it possible to obtain a straight line connecting the clay concentration to the TOC value.

Example 5: Realization of a calibration curve of the absorbance value as a function of the clay concentration

50 g of AFNOR sand (free of clay) are taken and introduced into a receptacle comprising 50 g of a composition (C1) of Example 1. The mixture is stirred for 30 seconds and then decanted for about 2 minutes so that the finest particles fall down in order to avoid clogging of the filter. 10 ml of supernatant are taken and then filtered using a 1 μm glass fiber syringe filter. The filtrate obtained is recovered in a glass tube for photometric measurement of the absorbance (A1). Before measuring the absorbance, 2 drops of HCl are added to the filtrate. Before measuring the absorbance of the filtrate, a blank is produced with a buffer solution (acetic acid / 0.1 M sodium acetate). The measurement of the absorbance of the composition (C1) is carried out and this value is deduced from the measurement of the absorbance (A1).

The same protocol is implemented with the following sands Osman sand, Signes sand, St Marthe sand, Lecieux sand, Fulchiron sand, Vernou sand, Vesseny sand, Goutrens sand, Bernières sand, Inerti Salinello sand, Siegwart sand, TRK sand, sand Sail s / s Couzan. The absorbance measurements (An) are carried out. Before measuring the absorbance, 2 drops of HCl are added to the filtrates. Before measuring the absorbance of the filtrate, a blank is produced with a buffer solution (acetic acid / 0.1 M sodium acetate). The absorbance of the composition (C1) is measured and this value is deduced from the absorbance (An) measurements.

A correlation with the straight line obtained in Example 4 makes it possible to obtain a curve of the absorbance value as a function of the clay concentration.

A similar protocol is implemented with the composition (C2) of Example 2.

Example 6: Realization of a correlation line between the quantity of AMAA to add to the absorbance value

4 mortars are made according to the following composition:

- 624.9 g of cement OEM I 52, 5N CE CP2 NF SPLC

- E / C = 0.6

- 734.98 cm 3 of sand

The granular curves of the mortars are homogenized by associating the sands of interest with Fulchiron sand which does not contain clay (this makes it possible not to be subject to the influence of the granular curve and therefore to study only the effect of clays), in the following volume proportions:

[Table 1]

The measurement of spreading at T5 and of maintenance was carried out for the reference mortar 1 not exhibiting any clay.

The spread is evaluated as follows:

A mold without bottom of frustoconical shape, reproduction on a scale of 0.5 of the Abrams cone (see standard NF 18-451, 1981) with the following dimensions: diameter of the upper circle = 5cm, diameters of the circle of the lower base = 10 cm, height 15 cm. After mixing the mortar containing the polymer, the mold is filled and the upper surface of the cone is leveled. The cone is lifted vertically and the spread is measured at 90 ° with a tape measure.

The spreading at T5 and holding measurements were carried out for mortars 2 to 4.

AMAA (CHRYSO®Quad 800) was added to mortars 2 to 4 until spreading measurements at T5 and maintenance similar to those of reference mortar 1 were obtained.

The results are as follows:

[Table 2]

We thus deduce a straight line of the quantity of AMAA to be used as a function of the sand and therefore of the quantity of clay (the quantity of clay of each of the sands having been obtained in Example 4) and by correlation with the curves of the Examples 4 and 5, the correlation curve of the AMAA concentration to be used as a function of the absorbance value is deduced therefrom.

The two curves obtained for the compositions (C1) and (C2) of Examples 1 and 2 are given respectively in Figures 1 and 2.

The calibration curves depend on the cements used.

Example 7: Procedure of the colorimetric test:

Provide a container (10OmL bottle) fitted with a stopper comprising the 50 ml of composition (C) of the invention;

Introduction of the sand taken into a 35mL container (i.e. approximately 10g of sand);

- Stirring for about 30 seconds then decantation;

- Sampling of the supernatant liquid (10mL syringe);

- Filtration (1 μm glass fiber syringe filter) in a container suitable for the photometric analysis of the absorbance;

- Photometric measurement of absorbance via a device allowing measurements at a wavelength of 525nm;

- Transfer of the value read on the device in an equivalence curve allowing the absorbance value to be linked to the dosage required in AMAA.

CLAIMS

1. Use of compound of formula (I) to determine the amount of clay intercalating superplasticizers in a sand and / or to determine the amount of AMAA Clay Activity Modifying Agent compound to be added to a hydraulic binder composition using a sand

R 1 - (OA) n -XR 2 (I)

in which

R 1 represents a C1 to C4 alkyl group, linear or branched, or a colored compound;

R 2 represents a colored compound;

A, each the same or different, independently represents a -CH2-CH2- group or an -OH (OH 3 ) -OH - group;

n represents an integer between 1 and 500, preferably between 4 and 250 X is O or NH.

2. Use according to claim 1, wherein

R 1 represents a methyl, propyl, ethyl or butyl group; and or

A represents a group -CH2-CH2-, -OH (OH 3 ) -OH -; and or

X is O or NH, preferably O; and or

n represents an integer between 1 and 500, preferably between 4 and 250.

3. Use according to claim 1 or 2, in which the colored compound is chosen from the following groups:

- Azobenzene derivatives having a neutralized COOH function or not reacting with the XH function;

- Acridine derivatives having a COOH function neutralized or not reacting with the XH function;

- Anthraquinone derivatives having a COOH function neutralized or not reacting with the XH function;

- Phthalocyanine derivatives having a neutralized COOH function or not reacting with the XH function;

- Quinone derivatives having a COOH function neutralized or not reacting with the XH function;

- Indophenol derivatives having a neutralized COOH function or not reacting with the XH function;

- Oxazone derivatives having a neutralized COOH function or not reacting with the XH function;

- Thiazine derivatives having a neutralized COOH function or not reacting with the XH function;

- Xanthene derivatives having a COOH function neutralized or not reacting with the XH function;

- Fluorone derivatives having a neutralized COOH function or not reacting with the XH function.

4. Use according to claim 1 or 2, in which the colored compound is chosen from the following groups:

- Azobenzene derivatives having a neutralized COOH function or not reacting with the XH function;

- Xanthene derivatives having a neutralized COOH function or not reacting with the XH function.

5. Use according to claim 1 or 2, in which the colored compound is chosen from the following groups:

- Azobenzene derivatives having a neutralized COOH function or not reacting with the XH function;

- Rhodamine derivatives having a neutralized COOH function or not reacting with the XH function.

6. Use according to claim 1 or 2, in which the colored compound is chosen from the following groups:

7. Use according to claim 1 or 2, in which the colored compound is chosen from the following groups:

8. Use of a composition (C) comprising a compound of formula (I) as defined according to any one of claims 1 to 7 to analyze and determine the amount of clay intercalating superplasticizers in a sand.

9. Use according to claim 8 wherein composition (C) comprises a pH buffer.

10. Method for determining the amount of agile intercalating superplasticizers in a sand comprising the following steps:

a) Provide a composition (C) as defined according to claim 8 or 9;

b) Take a sample of the sand to be analyzed;

c) Mix composition (C) with the sand sample in a container and stir; d) Filter the mixture obtained in step c);

e) Determine, as a function of the color of the solution obtained in step d), the concentration of clays intercalating the superplasticizers in the sand.

1 1. Method according to claim 10, in which step e) is carried out by a visual determination of the color and the correlation of this color to a range of quantity of clays intercalating the superplasticizers or by photometric measurement then comprising the steps e1) of photochemical measurement of the absorbance of the filtrate obtained in step d) and a step e2) of subtracting the value obtained in step e) from the photochemical measurement of the absorbance of composition (C) and of transfer of the value on a calibration curve to determine the percentage by weight of clay intercalating the superplasticizers in the sand.

12. Method for determining the amount of AMAA Clay Activity Modifying Agent to be added to a sand for its use in a hydraulic binder composition comprising the following steps:

- Implementation of the method for determining the amount of clay intercalating the superplasticizers in a sand according to claim 10 or 1 1;

- Construct a correlation curve making it possible to relate the absorbance value of the solution to the concentration of clay intercalating the superplasticizers of a sand and to the quantity of AMAA to be implemented to counter the harmful effect of the clay ;

- Report the value obtained by implementing the method according to claim 10 or 11 on the correlation curve and deduce therefrom the amount of AMAA Clay Activity Modifying Agent to be used.

13. Method for determining the amount of AMAA Clay Activity Modifying Agent to be added to a sand for its use in a hydraulic binder composition comprising the following steps:

i) Provide a composition (C) according to any one of claims 8 or 9; ii) Take a sample of the sand to be analyzed;

iii) Mix composition (C) with the sand sample in a container and stir; iv) Filter the mixture obtained in step iii);

v) Determine, as a function of the color of the solution obtained in step iv), the amount of AMAA to add.

14. Kit for implementing the method according to claims 10 to 13, comprising:

- A container provided with a stopper comprising the composition (C) according to any one of claims 8 or 9;

- A container for the determination of the sand sample;

- A means of taking liquid;

- A means of filtration;

- A receptacle for collecting the filtrate;

- A calibration curve making it possible to relate the color to the concentration of clay intercalating the superplasticizers of the sand and / or a correlation curve making it possible to relate the color to the quantity of AMAA Clay Activity-Modifying Agent at use.

15. Kit according to claim 14 further comprising an apparatus for photometric measurement of absorbance.