Method for analysing the quantity of clay in a sand

1 . A method for determining the concentration of superplasticizer-intercalating clays in a sand, comprising:

a) providing a composition (C) comprising a compound of formula (I) R 1 μ—(OA) n —XR 2 (I)

where:

R 1 is a linear or branched C1 to C4 alkyl group, or a coloured subunit;

R 2 is a coloured subunit;

A, each the same or different, is independently —CH 2 —CH 2 — or —CH(CH 3 )—CH 2 —;

n is an integer of between 1 and 500; and

X is O or NH;

b) taking a sample of the sand to be analysed;

c) mixing composition (C) with the sample of the sand in a container and agitating, to obtain a mixture;

d) filtering the mixture obtained at step c), to obtain a solution; and

e) determining the concentration of superplasticizer-intercalating clays in the sand as a function of the colour of the solution obtained at step d).

2 . The method according to claim 1 , wherein step e) is performed by visual determination of the colour and correlation of this colour with a range of quantities of superplasticizer-intercalating clays, or step e) is performed by photometric measurement and further comprises:

step e1) measuring a value of absorbance of the solution obtained at step d) by photometry,

step e2) subtracting the value of absorbance obtained at step e1) from a value, measured by photometry, of absorbance of composition (C), to obtain a difference, and

step e3) comparing the difference to a calibration curve to determine the weight percentage of superplasticizer-intercalating clays in the sand.

3 . The method according to claim 1 , wherein

R 1 is a methyl, propyl, ethyl or butyl group.

4 . The method of claim 3 , wherein X is O.

5 . The method of claim 4 , wherein n is an integer between 4 and 250.

6 . The method according to claim 1 , wherein the compound of formula (I) results from a reaction of a compound of formula (II) Y—(OA) n —XH (II) with a reactant compound;

where:

Y is a linear or branched C1 to C4 alkyl group; and

A, X and n are such as defined for the compound of formula (I); and

the reactant compound is selected from:

a derivative of azobenzene having a COOH functional group or a COO − functional group and capable of reacting with the XH functional group,

a derivative of acridine having a COOH functional group or a COO − functional group and capable of reacting with the XH functional group,

a derivative of anthraquinone having a COOH functional group or a COO − functional group and capable of reacting with the XH functional group,

a derivative of phthalocyanine having a COOH functional group or a COO − functional group and capable of reacting with the XH functional group,

a derivative of quinone having a COOH functional group or a COO − functional group and capable of reacting with the XH functional group,

a derivative of indophenol having a COOH functional group or a COO functional group and capable of reacting with the XH functional group,

a derivative of oxazone having a COOH functional group or a COO − functional group and capable of reacting with the XH functional group,

a derivative of thiazine having a COOH functional group or a COO − functional group and capable of reacting with the XH functional group,

a derivative of xanthene having a COOH functional group or a COO − functional group and capable of reacting with the XH functional group, and

a derivative of fluorone having a COOH functional group or a COO − functional group and capable of reacting with the XH functional group.

7 . The method according to claim 1 , wherein the compound of formula (I) results from a reaction of a compound of formula (II) Y—(OA) n —XH (II) with a reactant compound;

where:

Y is a linear or branched C1 to C4 alkyl group; and

A, X and n are such as defined for the compound of formula (I); and

the reactant compound is selected from:

a derivative of azobenzene having a COOH functional group or a COO − functional group and capable of reacting with the XH functional group, and

a derivative of xanthene having a COOH functional group or a COO − functional group and capable of reacting with the XH functional group.

8 . The method according to claim 1 , wherein the compound of formula (I) results from a reaction of a compound of formula (II) Y—(OA) n —XH (II) with a reactant compound;

where:

Y is a linear or branched C1 to C4 alkyl group; and

A, X and n are such as defined for the compound of formula (I); and

the reactant compound is selected from:

a derivative of azobenzene having a COOH functional group or a COO − functional group and capable of reacting with the XH functional group, and

a derivative of rhodamine having a COOH functional group or a COO − functional group and capable of reacting with the XH functional group.

9 . The method according to claim 1 , wherein each coloured subunit is independently selected from:

10 . The method according to claim 1 , wherein each coloured subunit is independently selected from:

11 . The method according to claim 1 , wherein composition (C) further comprises a pH buffer.

12 . The method of claim 1 , wherein n is an integer between 4 and 250.

13 . A method for determining an amount of clay mitigation agent (CMA) to be added to a sand for use in a hydraulic binder composition, comprising:

1) plotting a correlation curve allowing a concentration of superplasticizer-intercalating clay in a sand type to be related to an amount of CMA to be used for preventing absorption of water and intercalation of superplasticizers by the clay;

2) applying the method for determining the concentration of superplasticizer-intercalating clays according to claim 10 to a sample of the sand to obtain a value corresponding to the concentration of superplasticizer-intercalating clays in the sand; and

3) comparing the value obtained after implementing the method according to claim 1 to the correlation curve and inferring the amount of CMA to be added.

14 . A method for determining an amount of clay mitigation agent (CMA) to be added to a sand for use in a hydraulic binder composition, comprising:

i) providing a composition (C);

ii) taking a sample of the sand;

iii) mixing the composition (C) with the sample of the sand in a container and agitating, to obtain a mixture;

iv) filtering the mixture obtained at step iii), to obtain a solution; and

v) determining the amount of CMA to be added as a function of the colour of the solution obtained at step iv);

wherein composition (C) comprises a compound of formula (I) R 1 —(OA) n —XR 2 (I)

where:

R 1 is a linear or branched C1 to C4 alkyl group, or a coloured subunit;

R 2 is a coloured subunit;

A, each the same or different, is independently —CH 2 —CH 2 — or −CH(CH 3 )—CH 2 —;

n is an integer of between 1 and 500; and

X is O or NH.

15 . The method of claim 14 , wherein n is an integer between 4 and 250.