METHOD FOR ANALYSING THE QUANTITY OF CLAY IN A SAND

Abstract

Disclosed is use of a compound of formula (I) to determine the quantity of clay in a sand and/or to determine the amount of CMA compound to be added to a hydraulic binder composition using a sand:

R.sup.1—(OA).sub.n-XR.sup.2  (I)

where: R.sup.1 is a linear or branched C1 to C4 alkyl groups, or a coloured compound; R.sup.2 is a coloured compound; A, each the same or different, are independently a —CH.sub.2—CH.sub.2— group or —CH(CH.sub.3)—CH.sub.2— group; n is an integer of between 1 and 500, preferably between 4 and 250; and X is O or NH.

Claims

1-9. (canceled)

10. A method for determining the quantity of superplasticizer-intercalating clay in a sand, comprising the following steps: a) Providing a composition (C) comprising a compound of formula (I)
R.sup.1—(OA).sub.n-XR.sup.2  (I) where: R.sup.1 is a linear or branched C1 to C4 alkyl group, or a coloured compound: R.sup.2 is a coloured compound; A, each the same or different, are independently a —CH.sub.2—CH.sub.2— group or —CH(CH.sub.3)—CH.sub.2— group; n is an integer of between 1 and 500: X is O or NH; b) Taking a sample of the sand to be analysed; c) Mixing composition (C) with the sand sample in a container and agitating; d) Filtering the mixture obtained at step c); e) Determining the concentration of superplasticizer-intercalating clays in the sand as a function of the colour of the solution obtained at step d).

11. The method according to claim 10, 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 by photometric measurement then comprising steps e1) for photometric measurement of the absorbance of the filtrate obtained at step d) and step e2) to subtract the value obtained at step e) from the photometric measurement of the absorbance of composition (C), and entering the value into a calibration curve to determine the weight percentage of superplasticizer-intercalating clays in the sand.

12. A method for determining the amount of Clay Mitigation Agent to be added to a sand suitable for use thereof in a hydraulic binder composition, comprising the following steps: Implementing the method to determine the quantity of superplasticizer-intercalating clay in a sand according to claim 10; Plotting a correlation curve allowing the absorbance value of the solution to be related to a concentration of superplasticizer-intercalating clay in a sand and to the amount of CMA to be used for countering the harmful effect of the clay; Entering the value obtained after implementing the method according to claim 10 into the correlation curve and inferring therefrom the amount of Clay Mitigation Agent CMA to be used.

13. A method for determining the amount of Clay Mitigation Agent CMA to be added to a sand suitable for use thereof in a hydraulic binder composition, comprising the following steps: i) Providing a composition (C); ii) Taking a sample of sand to be analysed; iii) Mixing composition (C) with the sand sample in a container and agitating; iv) Filtering the mixture obtained at step iii); 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.sup.1—(OA).sub.n-XR.sup.2  (I) where: R.sup.1 is a linear or branched C1 to C4 alkyl group, or a coloured compound; R.sup.2 is a coloured compound; A, each the same or different, are independently a —CH.sub.2—CH.sub.2— group or —CH(CH.sub.3)—CH.sub.2— group; n is an integer of between 1 and 500: X is O or NH.

14. A kit to implement the method according to claim 10, comprising: A container fitted with a stopper comprising composition (C); A container to dose the sand sample; Means for sampling a liquid; Filtering means; A container to recover the filtrate; A calibration curve allowing colour to be related to a concentration of superplasticizer-intercalating clay in the sand and/or a correlation curve allowing colour to be related to the amount of Clay Mitigation Agent CMA to be used; wherein composition (C) comprises a compound of formula (I)
R.sup.1—(OA).sub.n-XR.sup.2  (I) where: R.sup.1 is a linear or branched C1 to C4 alkyl group, or a coloured compound; R.sup.2 is a coloured compound; A, each the same or different, are independently a —CH.sub.2—CH.sub.2— group or —CH(CH.sub.3)—CH.sub.2— group; n is an integer of between 1 and 500; X is O or NH.

15. The kit according to claim 14 further comprising an instrument for photometric measurement of absorbance.

16. A kit to implement the method according to claim 11, comprising: A container fitted with a stopper comprising composition (C); A container to dose the sand sample; Means for sampling a liquid; Filtering means; A container to recover the filtrate; A calibration curve allowing colour to be related to a concentration of superplasticizer-intercalating clay in the sand and/or a correlation curve allowing colour to be related to the amount of Clay Mitigation Agent CMA to be used; wherein composition (C) comprises a compound of formula (I)
R.sup.1—(OA).sub.n-XR.sup.2  (I) where: R.sup.1 is a linear or branched C1 to C4 alkyl group, or a coloured compound; R.sup.2 is a coloured compound; A, each the same or different, are independently a —CH.sub.2—CH.sub.2— group or —CH(CH.sub.3)—CH.sub.2— group; n is an integer of between 1 and 500; X is O or NH.

17. The kit according to claim 16 further comprising an instrument for photometric measurement of absorbance.

18. The method according to claim 10, wherein R.sup.1 is a methyl, propyl, ethyl or butyl group; and/or A is a group —CH.sub.2—CH.sub.2—, —CH(CH.sub.3)—CH.sub.2—; and/or X is O or NH; and/or n is an integer of between 1 and 500.

19. The method according to claim 10, wherein the coloured compound is selected from among the following groups: Derivatives of azobenzene having a COOH function whether or not neutralised reacting with the XH function; Derivatives of acridine having a COOH function whether or not neutralised reacting with the XH function; Derivatives of anthraquinone having a COOH function whether or not neutralised reacting with the XH function; Derivatives of phthalocyanines having a COOH function whether or not neutralised reacting with the XH function; Derivatives of quinone having a COOH function whether or not neutralised reacting with the XH function; Derivatives of indophenol having a COOH function whether or not neutralised reacting with the XH function; Derivatives of oxazone having a COOH function whether or not neutralised reacting with the XH function; Derivatives of thiazine having a COOH function whether or not neutralised reacting with the XH function; Derivatives of xanthene having a COOH function whether or not neutralised reacting with the XH function; Derivatives of fluorone having a COOH function whether or not neutralised reacting with the XH function.

20. The method according to claim 10, wherein the coloured compound is selected from among the following groups: Derivatives of azobenzene having a COOH function whether or not neutralised reacting with the XH function; Derivatives of xanthene having a COOH function whether or not neutralised reacting with the XH function.

21. The method according to claim 10, wherein the coloured compound is selected from among the following groups: Derivatives of azobenzene having a COOH function whether or not neutralised reacting with the XH function; Derivatives of rhodamine having a COOH function whether or not neutralised reacting with the XH function.

22. The method according to claim 10, wherein the colour compound is selected from among the following groups: ##STR00012##

23. The method according to claim 10, wherein the colour compound is selected from among the following groups: ##STR00013##

24. The method according to claim 10, wherein composition (C) comprises a pH buffer.

25. The kit of claim 17, wherein n is an integer between 4 and 250.

26. The method of claim 18, wherein X is O.

27. The method of claim 26, wherein n is an integer between 4 and 250.

28. The method of claim 10, wherein n is an integer between 4 and 250.

29. The method of claim 13, wherein n is an integer between 4 and 250.

Description

[0157] A description of the present invention is now given with the aid of nonlimiting examples.

[0158] FIG. 1 illustrates the correlation curve between the concentration of CMA to be used and the absorbance value measured for composition (C1) in Example 1.

[0159] FIG. 2 illustrates the correlation curve between the concentration of CMA to be used and the absorbance value measured for composition (C2) in Example 2.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Example 1: Synthesis 1 of a Composition (C1) of the Invention

[0160] A twin-neck round bottom flask fitted with a Dean Stark was charged with 8.08 g of compound A, 140.80 g of MPEG 5000 and 1.13 g of sodium hydroxide solution (50% dry extract) and placed under agitation. The reaction medium was brought to 165° C. under a vacuum of 20 mbars. The reaction medium was held under these conditions for 6 h. The temperature was lowered to room temperature and the reaction medium diluted with a buffer (acetic acid/0.1 M sodium acetate) to obtain the desired dry extract (0.04 weight %).

##STR00009##

Example 2: Synthesis of a Composition (C2) of the Invention

[0161] A twin-neck round bottom flask fitted with a Dean Stark was charged with 3.04 g of compound B, 31.71 g of MPEG 5000 and 0.25 g of sodium hydroxide solution (50% dry extract) and placed under agitation. The reaction medium was brought to 165° C. under a vacuum of 20 mbars. The reaction medium was held under these conditions for 6 h. The temperature was lowered to room temperature and the reaction medium diluted to obtain the desired dry extract (0.1 weight %).

##STR00010##

Example 3: Synthesis of a Composition (C3) of the Invention

[0162] A twin-neck round bottom flask fitted with a Dean Stark was charged with 7.60 g of compound C, 141.27 g of MPEG 5000 and 1.13 g of sodium hydroxide solution (50% dry extract) and placed under agitation. The reaction medium was brought to 165° C. under a vacuum of 20 mbars. The reaction medium was held under these conditions for 6 h. The temperature was lowered to room temperature and the reaction medium diluted to obtain the desired dry extract (0.04 weight %).

##STR00011##

Example 4: Plotting a Straight Line Linking Clay Concentration with TOC Value

[0163] Consumption of MPEG5000 by clays, Montmorillonite in particular, is determined by the difference between the amount of MPEG 5000 in solution before adding sand to the polymer solution and after a contact time of 5 min between the sand and this solution. The TOC content in the filtrate of a sand suspension without polymers is also measured and used as a blank for TOC measurements.

[0164] TOC measurement was performed on the initial solutions and on the filtrates with a SHIMADZU TOC-VCPN analyser. TOC was calculated by the difference between the amount of total carbon (obtained by carbonisation of the solution and infrared measurement of the quantity of CO.sub.2 released) and the quantity of inorganic carbon (obtained by acidification of the solution to pH<1 and release of dissolved CO.sub.2 by bubbling with synthetic air). The amount of consumed MPEG5000 was calculated by the difference between the amount added to the initial solution and the amount measured in the filtrates.

Consumption of MPEG 5000 was measured on different sands sampled on site for initial doses of 0.4. The montmorillonite equivalent (EqMnt) was calculated from the following equation:

[00002]$\begin{array}{cc}\mathrm{EqMnt}=\frac{m_{\mathrm{consumed}\mathrm{MPEG}}+0.3648}{1.1943}& \left(1\right)\end{array}$

The sands sampled on site were the following: Osman sand, Signes sand, St Marthe sand, Lecieux sand, Fulchiron sand, Vernou sand, Vesseny sand, Goutrens sand, Bernieres sand, Inerti Salinello sand, Siegwart sand, TRK sand, Sail s/s Couzan sand.
This allows a straight line to be obtained linking clay concentration with TOC value.

Example 5: Obtaining a Calibration Curve of Absorbance Value as a Function of Clay Concentration

[0165] 50 g of AFNOR sand (free of clay) were sampled and placed in a container comprising 50 g of composition (C1) of Example 1. The mixture was agitated 30 seconds and left to settle for about 2 minutes so that the finest particles fell to the bottom to prevent clogging of the filter. 10 ml of supernatant were taken and filtered with a 1 μm glass fibre syringe filter. The filtrate obtained was recovered in a glass tube for photometric measurement of absorbance (A1). Before absorbance measurement, 2 drops of HCl were added to the filtrate. Before measurement of absorbance of the filtrate, a blank was prepared with a buffer solution (acetic acid/0.1 M sodium acetate). The absorbance of composition (C1) was measured and this value subtracted from absorbance measurement (A1).
The same protocol was followed with the following sands: Osman sand, Signes sand, St Marth sande, Lecieux sand, Fulchiron sand, Vernou sand, Vesseny sand, Goutrens sand sand, sandBernieres, Inerti Salinello sand, Siegwart sand, TRK sand, Sail s/s Couzan sand. Absorbance was measured (An). Before absorbance measurement, 2 drops of HCl were added to the filtrates. Before measuring absorbance of the filtrate, a blank was prepared with a buffer solution (acetic acid/0.1 M sodium acetate). The absorbance of composition (C1) was measured and this value subtracted from absorbance measurements (An).
Correlation with the straight line obtained in Example 4 allowed a curve of absorbance value to be obtained as a function of clay concentration.
A similar protocol was followed with composition (C2) of Example 2.

Example 6: Obtaining a Correlation Straight Line Between Amount of CMA to be Added and Absorbance Value

[0166] 4 mortars were prepared with the following composition: [0167] 624.9 g of CEM I 52.5N CE CP2 NF SPLC cement [0168] W/C=0.6 [0169] 734.98 cm.sup.3 of sand
The aggregate curves of the mortars were homogenised by associating the sand of interest with Fulchiron sand which does not contain clay (to avoid influence of the aggregate curve and therefore only examine the effect of the clays), in the following volume proportions:

TABLE-US-00001 TABLE 1 Volume fraction of Volume fraction of Sand of sand of interest Fulchiron sand interest (weight %) (weight %) Mortar 1 - Ref. AFNOR 69.5 30.5 Mortar 2 Sail sous 49 51 Couzan Mortar3 Siegwart 78.6 21.4 Mortar 4 Vernou 59.3 40.7.
Slump at T5 and slump retention were measured for reference mortar 1 not containing clay. Slump was assessed as follows:

[0170] A cone-shaped bottomless mould was used reproducing the Abrams cone on a scale of 0.5 (see standard NF 18-451, 1981) having the following dimensions: diameter of upper circle=5 cm, diameter of base circle=10 cm, height 15 cm. After mixing the mortar containing the polymer, it was poured into the mould and levelled flush with the top surface of the cone. The cone was lifted vertically and slump measured at 900 with a tape measure.

Slump at T5 and slump retention were measured for mortars 2 to 4.
The CMA (CHRYSO@Quad 800) was added to mortars 2 to 4 until measurements of slump at T5 and slump retention were similar to those of the reference mortar 1.
The results were as follows:

TABLE-US-00002 TABLE 2 Recommended CMA dosage (wt. % sand of interest) Mortar 1 - Ref — Mortar 2 0.3 Mortar 3 0.25 Mortar 4 0.15
A straight line can therefore be drawn between the amount of CMA to be used as a function of sand type and hence clay content (the quantity of clay in each of the sands having been obtained in Example 4), and by correlation with the curves in Examples 4 and 5 the correlation curve can be inferred indicating the CMA concentration to be used as a function of absorbance value.
The two curves obtained for compositions (C1) and (C2) in Examples 1 and 2 are given in FIGS. 1 and 2 respectively.
The calibration curves are dependent on the cements used.

Example 7: Operating Mode of the Colorimetric Test

[0171] Providing a container (100 mL bottle) fitted with a stopper comprising 50 ml of composition (C) of the invention. [0172] Placing the sampled sand in a 35 mL container (i.e. about 10 g of sand). [0173] Agitating for about 30 seconds and leaving to settle. [0174] Taking a sample of the supernatant liquid (10 mL syringe). [0175] Filtering (1 μm glass fibre syringe filter) into a container adapted for photometric analysis of absorbance. [0176] Photometric measurement of absorbance with an instrument allowing measurements at a wavelength of 525 nm. [0177] Entering the value given by the instrument onto an equivalence curve allowing absorbance value to be related to required CMA dosage.