FR2540551A1 - Chemical jack based on plaster and on dead-burnt quicklime - Google Patents

Abstract

Product comprising approximately 40 to 60% by weight of plaster and approximately 60 to 40% by weight of dead-burnt quicklime, water and additives. Slow expansion capable of producing considerable stresses. Application to demolition and clearing, with maximum thrust being obtained relatively rapidly.

Description

Chemical cylinder based on plaster and quicklime.

 The present invention relates to the sector of chemical cylinders used for clearing, demolition and similar applications, such as cutting construction or siding rocks in sandstone quarries or marble for example.

 By "chemical jack" is meant here an expansive mixture capable of exerting its expansion considerable stresses in a more or less long time. Flows in a hole drilled in a rock, or a block of concrete, etc., such a product must be capable of causing the rock or block to burst.

 There is currently a product of this type whose manufacture uses a clinker cement very rich in lime.

 Another product based on cement and quicklime is also known.

 These two products have many disadvantages. In particular, the pressure exerted increases only very slowly and the bursting of the material to be destroyed is sufficient only after a very long delay.

 The present invention relates instead to a chemical cylinder to obtain much faster maximum pressure, which is a considerable advantage for the professional (much faster release of the site).

 An originality of the product according to the invention lies in the fact that it consists essentially of plaire and quicklime (and of course water).

 As plaster, we can use a natural autoclave type flat, form "a", or a synthetic plaster, phosphogypsum, form "alpha", giving preferably an acidic pH (3 to 65.

The best results were obtained with the plaster "LUDUR G" marketed by the company GIULINI, Republic
Federal of Germany.

The essential characteristics sought for plaster are
- initial state liquid or powder,
fast curing speed,
- good increase over time in the regions
mechanical equipments,
strong compressive strength.

 Other plasters meeting these criteria may be used.

The second essential constituent of the product according to the invention is a hydraulic expansive product whose essential characteristics must be
a liquid or powdery initial state,
- a rather slow expansion, because it must not
manifest itself after the hardening of the
binder (here, the plaster),
a final solid powdery state,
- an ability to develop a very strong
pressure during expansion.

 A burnt CaO quicklime will most preferably be used. It is known that the transformation of CaO quicklime into Ca (OH) 2 slaked lime results in a volume expansion of 1.8 times. It is also necessary that the quicklime is "overcooked" 1: indeed, if the lime has not been heated to more than 10000C, the hydration occurs instantly.

 The product according to the invention may comprise conventional additives, in particular a superplasticizer (to obtain a pasty product having a good flowability, without it being necessary to resort to an excess of water which would lower the resistance in particular. mechanical binder used, here the plaster).

 If necessary, add a binder set accelerator in order to obtain good mechanical characteristics more quickly.

Most preferably the product will finally contain water in the following proportions
water / plaster approximately 18.6% by weight
water / quicklime about 32.2% by weight that allow to work without excess water.

The product according to the invention will contain, with regard to the plaster + quicklime combination, from 40 to 60% of plaster and from 60 to 40% by weight of quicklime, by weight
The plaster plays in the product according to the invention a ralle of binder and will take "piegeant" crystals of quicklime (thus, the expansive mixture will not escape the hole in which it has been cast). Then, the slow hydration of the burnt quicklime starts; it will generate the radial pressure stresses that will burst the block to destroy.

 Plaster had never been used in this binder function yet, in the technical sector considers.

It is largely due to the surprising properties of the product according to the invention.

 It will be noted that the prior art uses a cement as a binder. Its setting speed is relatively slow, it is necessary in the known products to use a quick lime strongly hardened so that its hydration does not begin before the binder. On the contrary, according to the invention, it will be possible to be content with a much less lime.

 Finally, it must be pointed out that the choice of binder here, plaster - is essential, because many hydraulic materials are not suitable for this function.

 Thus, if a quicklime is used as the binder, an explosion occurs about 9 minutes after the addition of water.

 Another binder, magnesia, is also not suitable.

 Part of the very interesting properties of the product according to the invention is undoubtedly due to the fact that the binder and the hydraulic expansive product are of different nature.

 According to the prior art, on the contrary, it is known that cement and quicklime are of the same nature and compatible.

 This is probably the reason why the plate was not previously used as a binder for making a chemical cylinder.

 Finally, the different nature of plaster and quicklime will allow according to the invention to introduce specific additives acting only on one or the other of these compositions, hence the additional advantage of being able to adapt the formulations with precision.

 The product according to the invention, which is intended for splitting rocks or concretes, is capable of acting in open cylindrical cavities drilled in the block to be destroyed: the pressure is exerted in the radial direction and it does not occur no output of the product through the hole of the hole.

 The pasty product according to the invention can be cast easily; it can also be pumped or put into the form of humidifiable cartridges (for example porous sheath for dipping in water immediately before use).

 The following examples illustrate the invention without, however, limiting its scope.

EXAMPLE 1
Formulations I, II and III
Tables I, II and III below show the details of the compositions of formulations I, II (IIa and IIb) and III (c).

 As a replacement for potassium sulphate, it will be possible to use ammonium fluosilicate, ammonium sulphate, diammonium phosphate, etc.

General procedure of the tests
The principle is to perform burst tests of "molds" made of an epoxy material whose tensile strength is determined elsewhere on "test pieces" cast from the same epoxy mass as the mold.

 The mold has a cylindrical shape having an equally cylindrical coaxial cavity. The "diameter" of the cross-section of the mold, "INT", the diameter of the cross-section of the cavity, the expression "e", the thickness of the wall which is deduced from the two preceding diameters, shall be designated as "EXT".

 For the test, the product to be tested is poured into the central cavity of several molds having the same INT, but e.

The relationship between the thrust (P) exerted by the test product, the tensile strength bT) of the constituent epoxy material of the mold (0 INT) and (e), is as follows
2 P (bars) = #T (bars) xe (cm) x
# INT (cm)
The tensile strength (#T) of the epoxy material is determined separately by means of test pieces
- either cylindrical, 56 mm, h 112 mm, for the test of
cracking described below,
- by dumbbell, of calibrated part
length 50 mm
section 5 x 10 mm for direct xT measurement, at a pulling speed of 10 mm / min.

EXAMPLE 2
The test procedure described above and a formulation according to the invention were used at 50% by weight of plaster and 50% by weight of ultrafine hardened quicklime, with a weight ratio of water to powder (plaster + quicklime). overcooking) equal to 0.35.

 The results obtained were summarized in Table IV below.

 The test temperature was 200C.

 This example shows that the product according to the invention leads to a very fast pushing up since one reaches 250 bars (average value) in less than one hour for the mold n 4.

EXAMPLE 3
The same test as that reported in Example 2, but at 10 ° C., was carried out.

 The results are summarized in Table V below.

EXAMPLE 4
Formulation I
The test product runs according to Formulation I (see Table I).

Weight ratio water / powders (plaster + lime) = 0.29
Test conducted at room temperature 220C
Epoxy mold
density 1.75 g / cm3
- tensile stress by splitting 245,5 bar
(average of 2 measurements)
[The splitting test consists in placing the cylindrical epoxy test piece horizontally on one of the plates of a press and exerting the pressure according to a generator: the value given is equal to the pressure which causes the cracking of the test-tube this test gives an approximate value of the actual tensile stress and is also referred to as the "Brasilian test"].

The results are collated in Table VI
below.

CONCLUSIONS
The expansion reaction occurs about 1 hour after grouting.

 The expansion reaction is not progressive, it occurs at a given moment with maximum thrust.

 The maximum thrust observed is between 206 and 244 bar (the pH of the plaster was 11.51).

EXAMPLE 5 Formulations II
The test product flows into the cavity corresponds to the formulation IIa or IIb of Table II below.

Formulation II a: water / powders (by weight) = 0.275
Formulation II b: water / powders (by weight) = 0.26
Epoxy mold
3
- density 1.73 g / cm
- tensile stress by splitting 281,5 bar
(average of two measurements)
The results are collated in Tables VII and VIII below.

CONCLUSIONS
This new series of tests confirms that the expansion reaction is not progressive. It occurs at a given moment with maximum thrust.

 For the formulation IIa, the maximum thrust is between the values 267 and 336-bars and is rather close to 336 bars.

 For formulation IIb: between 266 and 337 bars (in both cases: plaster pH = 3.50).

EXAMPLE 6
Formulation III
The cast product meets the formulation (c), Table III below.

water / powders (by weight) 0,26
Epoxy mold: same characteristics as in Example 5.

 The results are summarized in Table IX below.

CONCLUSION GENER4LE
Examples 4, 5 and 6 show that, in order to obtain a greater maximum thrust, it is necessary to look for a plaster giving an acidic pH (see Table X below). This in itself is surprising given the basic nature of lime. In the prior art, it was sought instead to use a basic binder (cement).

EXAMPLE 7
Bursting test of a concrete block
Concrete block parameters flow. CPJ 45 R (Champagnole cement) 300 to 350 kg / m3 Sand of 0 to 16 mm grain size. Water / cement: 0.34 by weight. Superplasticizer - water reducer: "MELMENT F10" = 1% / cement
Vibrated concrete.

Block dimensions
length: 3.2m, width: 0.5m, height: 0.5m.

9 9 reservations (by HDPE pipes (high density polyethylene) -
outside diameter: 40 mm, length: 500 mm) at 0.4 m from the outer
half of the block with 0.3 m as center distance.

 The appearance of the holes is smooth once the HDPE tubes are removed.

Tensile strength by splitting at D + 27 days, day
of the test = 34.6 / # 5.4% / bar; average of three measurements Resistance to compression at D + 27 days, the day of the test =
384 bar, average of two measurements.

Product Settings
Formula (c) described in Table III was used
Plaster = 45%
Lime = 55%
water / powders = 0.26
Plaster pH = 3.81
Parameters of the test
Hand-dipped for 60 to 90 s Ambient temperature = 290C (good dry weather) Start of frost in the waxed paper cup = 30 min. Start of expansion in the waxed paper cup = 41 min
(It is found that paraffin melts).

 After a duration of 140 min, cracks of 1 / 10th mm can be seen between the nine holes of the concrete block.

 After a duration of 270 min, a crack perpendicular to the longitudinal direction of the nine holes appears on one side, at the second hole with respect to one end of the block.

 After a period of 17 h 30 min, the crack between the nine holes widened = 10 to 15 mm. On the other hand, between the edge of the block and the first hole, there is a crack of 2 mm wide at the hole which tapers to 1 / 10th mm at the edge of the block (this being valid for both ends of the concrete block). Two cracks (5 mm wide) perpendicular to the longitudinal direction of the nine holes appear at the second hole with respect to each end.

 After a period of 20 hours, the crack between the nine holes widened = 20 mm. Qualitative (width) and quantitative increase (number of fissures) of the bursting process.

 After a period of 21 hours, accentuation of the destruction process.

 After 44 hours, accentuate the destruction process. The longitudinal fissure is at least 30 to 50 mm wide.

The transverse cracks mentioned above are about 5 to 10 mm wide. Appearance of longitudinal cracks at the ends of the block (length: 0.40 m) between the edge of the block and the first hole.

 After 90 h, the longitudinal crack is 60 to 70 mm wide.

 The product remains in the form of casting, that is to say cylindrical and becomes friable to the touch.

CONCLUSIONS
1) It can be considered that the concrete block was really weakened after 15 to 20 hours.

 2) The product does not present any particular danger, during storage, during pouring and while awaiting bursting.

3) The basic calculation for defining hole diameter and hole spacing is as follows
diameter of the hole. 40 mm
distance between holes (center distance) 300 mm
thrust = 250 bar (safety margin), ie a
tensile strength of the concrete = 33 bar.

 There is every reason to believe that the maximum thrust is greater than 250 bar (ends of the concrete block, length = 400 mm).

 4) Concrete is by nature alkaline and it is possible that the alkalinity of the substrate inhibits the spontaneous character of the destruction of the block, because, in fact, the expansion is progressive and the maximum pressure is not reached as quickly as in the epoxy molds tformulations (I), (II) and (III)].

TABLE I
FORMULATION I
Plaster 40% by weight
Cooked quicklime 60% by weight

<tb>. <SEP> Plaster <SEP> (LUGUR <SEP> G / C) <SEP> 1 <SEP> 526 <SEP> g <SEP> = <SEP> 39.37% <SEP> 30.52%
<tb>. <SEP> Superplasticizer
<tb><SEP> (OROTAN <SEP> SN)
<tb><SEP> 1.50% / plaster <SEP> + <SEP> lime <SEP> 57 <SEP> g <SEP> = <SEP> 1.47% <SEP> 1.14%
<tb> Sulfate <SEP> of <SEP> potassium
<tb><SEP> 0.20% / plaster <SEP> 3 <SEP> g <SEP> = <SEP> 0.08% <SEP> 0.06%
<tb>. <SEP> Lime <SEP> fast <SEP> overcooked
<tb><SEP> granulometry <SEP> 0-6 <SEP> mm <SEP> 2 <SEP> 290 <SEP> g <SEP> = <SEP> 59.08% <SEP> 45.80%
<tb><SEP> 100
<tb><SEP> Water <SEP> 22.48% <SEP>
<tb><SEP> 100
<tb> - pH plaster 11.51 - ratio water / powders (plaster + lime) = 0.29 by weight
TABLE II
FORMULATIONS IIa and IIb
IIa Plaster 50% by weight
Cooked quicklime 50% by weight

<tb>. <SEP> Plaster <SEP> LUGUR <SEP> G / C <SEP> 750 <SEP> g <SEP> = <SEP> 49.21% <SEP> 38.60% <SEP>
<tb>. <SEP> Superplasticizer
<tb><SEP> OROTAN <SEP> SN
<tb><SEP> 1.50% / plaster <SEP> + <SEP> lime <SEP> 22.5 <SEP> g <SEP> = <SEP> 1.48% <SEP> 1.16%
<tb>. <SEP> Sulfate <SEP> of <SEP> potassium
<tb><SEP> 0.20% / plaster <SEP> 1.5 <SEP> g <SEP> = <SEP> 0.10% <SEP> 0.08%
<tb>. <SEP> Lime <SEP> fast <SEP> overcooked
<tb><SEP> 0-6 <SEP> mm <SEP> 750 <SEP> g <SEP> = <SEP> 49.21% <SEP> 38.6%
<tb><SEP> 100
<tb><SEP> Water <SEP> 21.57% <SEP>
<tb><SEP> 100
<tb> - pH plaster = 3.50 - water / powder ratio = 0.275 by weight
TABLE II (continued)
IIb Plaster 60% by weight
Cooked quicklime - 40% by weight

<tb>. <SEP> Plaster <SEP> LUGUR <SEP> G / C <SEP> 900 <SEP> g <SEP> = <SEP> 59.04% <SEP> 48.86%
<tb>. <SEP> Superplasticizer
<tb><SEP> OROTAN <SEP> SN
<tb><SEP> 1.50% / plaster <SEP> + <SEP> lime <SEP> 22.5 <SEP> g <SEP> = <SEP> 1.48% <SEP> 1.17%
<tb>, <SEP> Sulfate <SEP> of <SEP> potassium
<tb><SEP> 0.20% / plaster <SEP> 1.8 <SEP> g <SEP> = <SEP> 0.12% <SEP> 0.10% <SEP>
<tb> Lime <SEP> fast <SEP> overcooked
<tb><SEP> 0-6 <SEP> mm <SEP> 600 <SEP> g <SEP> = <SEP> 39.30% <SEP> 31.24%
<tb><SEP> 100
<tb><SEP> Water <SEP> 20.63%
<tb><SEP> 100
<tb> - pH plaster 3.50 - water / powder ratio = 0.26 by weight
TABLE III
FORMULATION III (c)
Plaster 45% by weight
Cooked quicklime 55% by weight.

<Tb>

. <SEP> Plaster <SEP> LUGUR <SEP> G / C <SEP> 675 <SEP> g <SEP> = <SEP> 44.30% <SEP> 35.16%
<tb>. <SEP> Superplasticizer
<tb><SEP> OROTAN <SEP> SN
<tb><SEP> 1,50% / plaster <SEP> + <SEP> lime <SEP> 22,5 <SEP> g <SEP> = <SEP> 1,47% <SEP> 1,17%
<tb><SEP> Sulfate <SEP> of <SEP> potassium
<tb><SEP> 0.20% / plaster <SEP> 1.35 <SEP> g <SEP> = <SEP> 0.09% <SEP> 0.07% <SEP>
<tb> Lime <SEP> live
<tb><SEP> 0-6 <SEP> mm <SEP> 825 <SEP> g <SEP> = <SEP> 54.14% <SEP> 42.97%
<tb><SEP> 100
<tb><SEP> Water <SEP> 20.63%
<tb><SEP> 100
<tb> - pH plaster 3.84 - water / powder ratio = 0.26 by weight.

TABLE IV (Example 2)

<tb> Mold <SEP>#<SEP><SEP> INT <SEP>#<SEP><SEP> EXT <SEP>##<SEP><SEP>(#)<SEP><SEP> Rupture
<tb><SEP> of the <SEP> mold
<tb><SEP> n <SEP> mm <SEP> mm <SEP> 280 <SE> 314 <SE> 348 <SEP> After
<tb><SEP> PUSH <SEP> P <SEP> (bars)
<tb><SEP> 1 <SEP> 40.3 <SEP> 61 <SEP> 144 <SEP> 161 <SEP> 179 <SEP> 35 <SEP> min
<tb><SEP> 2 <SEP> 40.4 <SEP> 63.4 <SEP> 159 <SEP> 179 <SEP> 198 <SEP> 38 <SEP> min
<tb><SEP> 3 <SEP> 40.4 <SEP> 69.2 <SEP> 200 <SEP> 224 <SEP> 248 <SEP> 47 <SEP> min
<tb><SEP> 4 <SEP> 40.6 <SEP> 72.8 <SEP> 222 <SEP> 249 <SEP> 276 <SEP> 53 <SEP> min
<tb> (*) determined on dumbbell test pieces by the step-by-step test
direct expressed in bars; the central value expresses the
average of the other two values.

TABLE V (Example 3)

<SEP> Mold <SEP>#<SEP> INT <SEP>#<SEP><SEP> EXT <SEP>##<SEP><SEP> (*) <SEP> Rupture
<tb><SEP> of the <SEP> mold
<tb> n <SEP> mm <SEP> mm <SEP> 280 <SE> 314 <SE> 348 <SEP> after
<tb><SEP> PUSH <SEP> P <SEP> (bars)
<tb><SEP> 1 <SEP> 40.3 <SEP> 60 <SEP> 137 <SEP> 154 <SEP> 170 <SEP> 80 <SEP> minutes <SEP> | <September>
<tb><SEP>,<SEP>.<September>
<Tb>

<SEP> 2 <SEP> 40.3 <SEP> 62.6 <SE> 155 <SE> 174 <SEP> 193
<tb> (*) cf. Table IV (**) No breakage of the mold.

65 mm) TABLEAU VI (Exemple 4)
Avec FORMULATION I

After 3:50, the outside diameter increases by almost 4% (62.6

65 mm) TABLE VI (Example 4)
With FORMULATION I

Parameters <SEP> of <SEP> mold <SEP> Pressure
<tb> Number <SEP> of <SEP> Number <SEP> of <SEP> Comments
<tb>#<SEP> EXT <SEP>#<SEP> INT <SEP> Calculated <SEP> Height
<tb> mold <SEP> mold
<tb> (mm) <SEP> (mm) <SEP> (mm)
<tb> 1 <SEP> 3 <SEP> 100 <SEP> 40 <SEP> 85 <SEP> 370 <SEP> bar <SEP> After <SEP> 55 <SEP> min, <SEP> chalking <SEP> with <SEP>SEP><SEP> level of the <SEP> hole
<tb> on <SEP> the <SEP> three <SEP> molds.
<Tb>

2 <SEP> 3 <SEP> 92 <SEP> 40 <SEP> 85 <SEP> 320 <SEP> bar <SEP> After <SEP> 60 <SEP> min, <SEP> chalking <SEP> at <SEP> level <SEP> of the <SEP> hole
<tb> on <SEP> the <SEP> three <SEP> molds.
<Tb>

3 <SEP> 3 <SEP> 79.8 <SEP> 40 <SEP> 90 <SEP> 244 <SEP> bar <SEP> After <SEP> 95 <SEP> min, <SEP> a <SEP> slot <SEP > next <SEP> a <SEP> generator <SEP> at the <SEP> bottom <SEP> of a <SEP> mold.
<Tb>

Explosion <SEP> fast <SEP> after <SEP> 55 <SEP> min <SEP> on <SEP> one <SEP> other
<tb> mold
<tb> 4 <SEP> 3 <SEP> 73.6 <SEP> 40 <SEP> 97 <SEP> 206 <SEP> bar <SEP> After <SEP> 45 <SEP> min, <SEP> a <SEP> crack <SEP> appears <SEP> on
<tb> two <SEP> molds.
<Tb>

At <SEP> same <SEP> moment <SEP> appears <SEP> a <SEP> second <SEP> crack <SEP> on <SEP> one <SEP> of <SEP> two <SEP> molds.
<Tb>

<SEP> 3 <SEP> 68 <SEP> 40 <SEP> 62 <SEP> 172 <SEP> bar <SEP> After <SEP> 53 <SEP> min, <SEP> a <SEP> SEP <SEP> appears <SEP> on
<tb> three <SEP> molds.
<Tb>

After <SEP> 60 <SEP> min, <SEP> one <SEP> second <SEP> crack <SEP> appears <SEP> on <SEP> two <SEP> molds.
<Tb>

TABLE VII (Example 5)
With FORMULATION IIa

Number <SEP> of <SEP> Number <SEP> of <SEP> Parameters <SEP> of <SEP> mold <SEP> Pressure
<tb> mold <SEP> molds <SEP> calculated <SEP> Comments
<tb>#<SEP> EXT <SEP>#<SEP> INT <SEP> Height
<tb> (mm) <SEP> (mm) <SEP> (mm)
<tb> 1 <SEP> 1 <SEP> 99.5 <SEP> 40 <SEP> 85 <SEP> 419 <SEP> bar <SEP> Mold <SEP> intact <SEP> after <SEP> 8 <SEP> h <SEP> and <SEP> 48 <SEP> h.
<Tb>

2 <SEP> 1 <SEP> 88.25 <SEP> 40.5 <SEP> 98 <SEP> 336 <SEP> bar <SEP> Separation <SEP> of <SEP> mold <SEP> after <SEP> 1 <SEP> h <SEP> 15.
<Tb>

3 <SEP> 1 <SEP> 78.7 <SEP> 40.25 <SEP> 91 <SEP> 267 <SEP> bar <SEP> The <SEP> mold <SEP> swells <SEP> radially, <SEP> its <SEP> diameter <SEP> external <SEP> increases <SEP> for <SEP> to reach
<tb> 80 <SEP> mm <SEP> after <SEP> 1 <SEP> h <SEP> 15. <SEP> This <SEP> diameter <SEP> remains
<tb> unchanged <SEP> after <SEP> 8 <SEP> h <SEP> and <SEP> 48 <SEP> h.
<Tb>

4 <SEP> 1 <SEP> 71.8 <SEP> 40.5 <SEP> 97 <SEP> 220 <SEP> bar <SEP><SEP>SEP> SEP <SEP> break after <SEP> 1 <SEP> h <SEP> 10.
<Tb>

<SEP> 1 <SEP> 67.2 <SEP> 40.5 <SEP> 63 <SEP> 188 <SEP> bar <SEP> Separation <SEP> of <SEP> mold <SEP> after <SEP> 1 <SEP> h <SEP> 15.
<Tb>

TABLE VIII (Example 5)
With FORMULATION IIb

Number <SEP> of <SEP> Number <SEP> of <SEP> Parameters <SEP> of <SEP> mold <SEP> Pressure
<tb> mold <SEP> molds <SEP> calculated <SEP> Comments <SEP> (*)
<tb>#<SEP> EXT <SEP>#<SEP> INT <SEP> Height
<tb> (mm) <SEP> (mm) <SEP> (mm)
<tb> 1 <SEP> 1 <SEP> 98.5 <SEP> 40 <SEP> 88 <SEP> 412 <SEP> bar <SEP> Nothing <SEP> to <SEP> report <SEP> after <SEP> 8 <SEP> h <SEP> and <SEP> 48 <SEP> h.
<Tb>

2 <SEP> 1 <SEP> 88.50 <SEP> 40.65 <SEP> 100 <SEP> 337 <SEP> bar <SEP> Nothing <SEP> to <SEP> report <SEP> after <SEP> 8 <SEP> h <SEP> and <SEP> 48 <SEP> h.
<Tb>

3 <SEP> 1 <SEP> 78.5 <SEP> 40.6 <SEP> 94 <SEP> 266 <SEP> bar <SEP> Nothing <SEP> to <SEP> report <SEP> after <SEP> 8 <SEP> h <SEP> and <SEP> 48 <SEP> h.
<Tb>

4 <SEP> 1 <SEP> 71.55 <SEP> 40.5 <SEP> 98 <SEP> 219 <SEP> bar <SEP> Nothing <SEP> to <SEP> report <SEP> after <SEP> 8 <SEP> h <SEP> and <SEP> 48 <SEP> h.
<Tb>

<SEP> 1 <SEP> 67.25 <SEP> 40.45 <SEP> 64 <SEP> 189 <SEP> bar <SEP> Nothing <SEP> to <SEP> report <SEP> after <SEP> 8 <SEP> h <SEP> and <SEP> 48 <SEP> h.
<Tb>

 (*) No breakage of the molds.

This test is critical of the 60% upper limit of plaster compared to plaster + lime.

Indeed, for: 60% plaster / 40% lime, it begins to have enough lime in the product.

TABLE IX (Example 6)
FORMULATION III (c)

Number <SEP> of <SEP> Number <SEP> of <SEP> Parameters of <SEP> mold <SEP> Pressure
<tb> mold <SEP> molds <SEP>#<SEP> EXT <SEP>#<SEP> INT <SEP> Height <SEP> calculated <SEP> Comments
<tb> (mm) <SEP> (mm) <SEP> (mm)
<tb> 1 <SEP> 1 <SEP> 98.4 <SEP> 40 <SEP> 88 <SEP> 411 <SEP> bar <SEP> Mold <SEP> intact <SEP> after <SEP> 24 <SEP> h .
<Tb>

2 <SEP> 1 <SEP> 88.3 <SEP> 40.65 <SEP> 100 <SEP> 340 <SEP> bar <SEP> Separation <SEP> of <SEP> mold <SEP> after <SEP> 1 <SEP> h <SEP> 50.
<Tb>

3 <SEP> 1 <SEP> 78 <SEP> 40.5 <SEP> 94 <SEP> 266 <SEP> bar <SEP> The <SEP> mold <SEP> swells <SEP> radially, <SEP> its <SEP > diameter <SEP> external <SEP> increases <SEP> for <SEP> to reach
<tb> 79.5 <SEP> mm, <SEP> after <SEP> 1 <SEP> h <SEP> 50 <SEP>: <SEP> this <SEP> diameter
<tb> remains <SEP> unchanged <SEP> after <SEP> 24 <SEP> h.
<Tb>

4 <SEP> 1 <SEP> 71.55 <SEP> 40.6 <SEP> 100 <SEP> 215 <SEP> bar <SEP><SEP>SEP> SEP <SEP> break after <SEP> 1 <SEP> h <SEP> 39 <SEP> min.
<Tb>

<SEP> 1 <SEP> 67.2 <SEP> 40.55 <SEP> 65 <SEP> 185 <SEP> bar <SEP> Separation <SEP> of <SEP> mold <SEP> after <SEP> 1 <SEP> h <SEP> 53 <SEP> min.
<Tb>

PAINTINGS
Comparison of the results obtained.

FORMULATION
<tb> I <SEP> IIa <SEP> IIb <SEP> IIIc (III)
<tb> Example <SEP> 4 <SEP> 5 <SEP> 5 <SEP> 6
<tb> pH <SEP> of <SEP> plaster <SEP> 11.51 <SEP> 3.50 <SEP> 3.50 <SEP> 3.84
<tb> Plaster <SEP> (% <SEP> in
<tb> weight <SEP> *) <SEP> 40 <SEP> 50 <SEP> 60 <SEP> 45
<tb> Resistance <SEP> to <SEP> la
<tb> compression <SEP> of
<tb> Product <SEP> CELTAMINE <SEP> 130 <SEP> 328 <SEP> 328 <SEP> 308
<tb> (**) <SEP> (bar)
<tb> Maximum <SEP> thrust <SEP> between <SEP> between <SEP> between <SEP> between
<tb> observed <SEP> (bar) <SEP> 206 <SEP> and <SEP> 244 <SEP> 267 <SEP> and <SEP> 336 <SEP> 266 <SEP> and <SEP> 337 <SEP> 266 <SEP> and <SEP> 340
<tb> (*) Lime: 100% complement; cf. Tables I to III.

(**) The product CELTAMINE is a product based on plaster and urea-formaldehyde resin (French patent application No. 80-16532) which makes it possible here to evaluate by comparison the quality of a plaster from the point of view of mechanical resistance. .

The resistance is measured 24 hours after the mixing of these constituents and water.

Claims (10)

R E V E N D I C A T IO N S  1 - Chemical cylinder, characterized in that it consists of a flowable or pumpable product is essentially made of plaster, crushed quicklime and water.  2 - A chemical cylinder according to claim 1, characterized in that the plaster + lime mixture consists of 40 to 60% by weight of plaster and 60 to 40% by weight of quicklime coked.  3 - A chemical cylinder according to claim 1 or 2, characterized in that the weight ratio water / plaster is about 18.6% and the weight ratio water / lime is about 32.2% by weight.  4 - A chemical cylinder according to any one of claims 1 to 3, characterized in that the weight ratio water / powders (plaster + lime) is between 0.25 and 0.30 approximately.  5 - A chemical cylinder according to any one of claims 1 to 4, characterized in that it responds to the following formulation (by weight) - plaster (pH = 11> 51) 30.52% - superplasticizer 1.14% - 0.06% potassium sulphate - quicklime  (particle size 0-6 mm) 45.80% - water 22.48% [water / powders = 0.29 by weight).  6 - A chemical cylinder according to any one of claims 1 to 4, characterized in that it corresponds to the following formulation (by weight) - plaster (pH = 3.50) 38.60% - superplasticizer 1.16% - 0.08% potassium sulphate - quicklime  (particle size 0-6 mm) 38.6% - water 21.57% [water / powders = 0.29 by weight].  7 - A chemical cylinder according to any one of claims 1 to 4, characterized in that it corresponds to the following formulation (by weight) - plaster (pH = 3.50) 48.86% - superplasticizer 1.17% - 0.10% potassium sulphate - quicklime  (particle size 0-6 mm) 31.24% - water 20> 63% (water / powders ratio = 0.26 by weight)  8 - A chemical cylinder according to any one of claims 1 to 4, characterized in that it corresponds to the following formulation (by weight) - plaster (pH = 3.84) 35.15% - superplasticizer 1.17% - 0.07% potassium sulphate - quicklime  (particle size 0-6 mm) 42.97% - water 20.63%  9 - A chemical cylinder according to any one of claimsl to 8, characterized in that it contains additives such as ammonium fluosilicate, ammonium sulfate, diammonium phosphate instead of potassium sulfate.  10 - Method for clearing or demolishing blocks of rock, concrete and the like, or cutting rocks, characterized in that it consists in mixing on the site the water and the powders of the slow explosives according to one of the following: any of claims 1 to 9, and pouring the chemical cylinder thus obtained into holes drilled in the block, so as to obtain the bursting of the block by expansion of the chemical jack.