Two-component composition for forming an injectable or pumpable organo-mineral material, and associated sealing methods and uses

Abstract

The present invention relates to a two-component composition consisting of a component A intended to be mixed, in situ, with a component B in order to form an injectable or pumpable organo-mineral compound, in particular for injection-sealing dynamic anchor bolts, comprising at least one alkali metal silicate, at least one polyisocyanate derivative and at least one cement. The component A further contains at least one polyol having a molecular mass of between 50 and 200 g/mol, at least one polymerisation catalyst comprising at least one polar function and at least one gelling agent and the component B further comprises at least one suitable

Claims

1. A two-component composition comprising: a component A mixed, in situ, with a component B in order to form an injectable or pumpable organo-mineral material or compound, the component A comprising essentially of at least one alkali metal silicate and the component B comprising essentially of at least one polyisocyanate prepolymer and at least one cement, wherein component A moreover contains at least one polyol with a molecular mass of between 50 and 200 g/mol, a polymerization catalyst comprising at least one primary amine or alcohol function and at least one gelling agent manifesting the final mixture of the two components A and B in the form of a gel without causing the mixture of said components to set, and in that the component B moreover comprises at least one compatible plasticizer, the final mixture of said components A and B leading to the formation of an organo-mineral material exhibiting compressive strength at 10% strain of at least 17 MPa, in accordance with the standard ISO 604, and shear strength of at least 7 MPa, in accordance with the standard AFTM D732, for setting times of between 20 seconds and 15 minutes at 20° C.

2. The two-component composition as claimed in claim 1, wherein the alkali metal silicate is a liquid sodium silicate with a molar ratio SiO.sub.2/Na.sub.2O of 1.6 to 3.5, such that Na.sub.2O.Math.xSiO.sub.2+H.sub.2O (x=1.6-3.5) is obtained, and preferably 1.8 to 2.8.

3. The two-component composition as claimed in claim 1, wherein the polyisocyanate prepolymer(s) have a total proportion of NCO groups of between 22% and 32%, and are selected from the group formed by: prepolymers based on diphenylmethane diisocyanate (MDI), diphenylmethane-4,4′-diisocyanate and polymeric MDI.

4. The two-component composition as claimed in claim 1, wherein the cement or the mixture of cements used is based on: an Artificial Portland Cement (CEM I), Composite Portland Cement (CEM II), Blast-Furnace Cement (CEM III), Pozzolanic Cement (CEM IV), Composite Cement (CEM V), a cement of strength class 32.5 or 42.5 or 52.5, a prompt cement, a prompt natural cement (PNC) NF P 15-314, or a molten high-alumina cement (CA) NF P 15-315, or else microcements.

5. The two-component composition as claimed in claim 1, wherein the plasticizer(s) are non-aqueous plasticizers that do not contain any group which chemically reacts with the isocyanate function.

6. The two-component composition as claimed in claim 1, wherein the component A is constituted by: 50% to 98% by weight, of at least one alkali metal silicate that is liquid; 1% to 40% by weight of at least one polyol with a molecular mass between 50 and 200 g/mol; 0.01% to 5% by weight of at least one polymerization catalyst; 0.01% to 5% by weight of at least one gelling agent; 0% to 10% by weight of water and 0% to 5% by weight of at least one compatible adhesion promoter; the sum of the constituents of the component A being 100%; and in that the component B is constituted by: 40% to 80% by weight of at least one isocyanate prepolymer; 1% to 20% by weight of at least one plasticizer; 5% to 50% by weight of at least one cement; 0% to 10% by weight of at least one rheological agent that avoids settling of the powders; 0% to 20% by weight of at least one filling agent which does not react with the isocyanate groups; 0% to 20% by weight of at least one flame retardant for the material formed; and 0% to 5% by weight of at least one compatible adhesion promoter; the sum of the constituents of the component B being 100%.

7. The two-component composition as claimed in claim 1, wherein the volumetric ratio AB between the component A and the component B is less than 1.

8. The two-component composition as claimed in claim 1, wherein the viscosity, measured at 20° C. using an MS Z3 DIN system at a rotational speed of 500+/−100 rpm, is between 50 and 1500 mPa.Math.s, for the component A and between 50 and 3000 mPa.Math.s for the component B.

9. A process for implementing a composition as claimed in claim 1, wherein the components A and B are injected using positive-displacement pumps or similar equipment that enable the injection to be performed while preserving the volumetric ratio between the various components in an anchoring hole via an injection tube or directly by a self-drilling or non-self-drilling anchoring bolt.

10. The implementing process as claimed in claim 9, wherein, in the case of the hollow anchoring bolt acting as an injection tube, it has an inlet and an outlet enabling the composition as defined in claim 1 to migrate into the drilling hole in order to plug the annular space between this anchoring bolt and the ground.

11. A two component composition as claimed in claim 1, for configured to seal any one of dynamic anchoring bolts, dynamic solid-shank anchoring bolts, dynamic hollow-shank anchoring bolts “Hollow Core Bolts”, and long anchors of the bolt-cable type referred to as “Long Tendons.”

12. The two-component composition as claimed in claim 3, wherein the polyisocyanate prepolymer(s) have a total proportion of NCO groups of between 25% and 28%.

13. The two-component composition as claimed in claim 6, wherein the component A is constituted by: 65% to 95% by weight of at least one alkali metal silicate that is liquid; 5% to 30% by weight of at least one polyol with a molecular mass between 50 and 200 g/mol; 0.025% to 2% by weight of at least one polymerization catalyst; 0.1% to 1% by weight of at least one gelling agent; 1% to 5% by weight of water and 1% to 3% by weight of at least one compatible adhesion promoter; the sum of the constituents of the component A being 100%; and in that the component B is constituted by: 50% to 70% by weight of at least one isocyanate prepolymer; 5% to 10% by weight of at least one plasticizer; 15% to 35% by weight of at least one cement; 1% to 5% by weight of at least one rheological agent that avoids settling of the powders; 1% to 5% by weight of at least one filling agent which does not react with the isocyanate groups; 5% to 10% by weight of at least one flame retardant for the material formed; and 1% to 3% by weight of at least one compatible adhesion promoter; the sum of the constituents of the component B being 100%.

14. The two-component composition as claimed in claim 7, wherein the volumetric ratio AB between the component A and the component B is between ½ and ⅔.

15. The two-component composition as claimed in claim 8, wherein the viscosity, measured at 20° C. using an MS Z3 DIN system at a rotational speed of 500+/−100 rpm, is between 200 and 1100 mPa.Math.s, for the component A and between 150 and 1500 mPa.Math.s for the component B.

Description

[0077] The invention will be better understood by virtue of the present description, which relates to preferred embodiments which are given by way of nomlimiting examples and explained with reference to the appended schematic drawing, in which:

[0078] FIG. 1 shows a photo of tests of compositions according to the present invention.

[0079] By way of examples and a comparison, mechanical characteristics were measured on different compositions:

[0080] Example 1: Composition making it possible to obtain a setting time of 2 to 3 minutes.

TABLE-US-00001 TABLE 1 Ratio component A/component B: 1/2 Component A with formulation (in % by weight): 91.5% sodium silicate grade 48/50 5.0% glycol (monoethylene glycol) 0.2% reaction catalyst (2-(2- dimethylaminoethoxy)ethanol) 0.3% gelling agent (diethanolamine DEA) 3.0% water Component B with formulation (in % by weight): 47.6% MDI prepolymer with an NCO content of 28% obtained by reacting an MDI prepolymer (Lupranat M20S, registered trade mark) with a diol of mol. mass 2000 g/mol (Lupranol 1000, registered trade mark) 10.4% plasticizers (5.2% BDGA and 5.2% methyl ester of rapeseed oil) 38.7% cement CEM I 52.5 1.7% rheological additive (Luvothix R-RF) 1.6% molecular sieve (Sylosiv)

[0081] The compressive strength at 10% strain (tested in accordance with ISO 604) of the resulting non-expanded material was 27.1 MPa after 24 hours at 20° C., the modulus of elasticity in compression was 332 MPa and the shear strength in accordance with ASTM D732 was 15.4 MPa.

[0082] Example 2: Composition making it possible to obtain a setting time of about 10 minutes at 20° C.

TABLE-US-00002 TABLE 2 Composition A - formulation (% by weight) A0832001 Sodium silicate grade 49-51 76.65 Water 3.0 Glycerol 20.0 2-(2- 0.05 dimethylaminoethoxy)ethanol Diethanolamine (DEA) 0.3 Total 100.0 Component B - formulation (% by weight) B0832001 B0832002 B0832003 Polymeric MDI 55.0 65.0 MDI prepolymer with an NCO 56.6 content of 28% obtained by reacting a polymeric MDI (Lupranat M20S, registered trade mark) with a diol (Lupranol 1000, registered trade mark) with a mol. mass of 2000 g/mol Plasticizer 4.2 5.0 (butyldiglycol acetate BDGA) Plasticizer (methyl ester 4.2 5.0 of rapeseed oil) SYLOSIV 2.0 2.0 2.0 Rheological agent 2.0 2.0 2.0 LEVOTHIX R-RF Filler: Kaolin OPTIWHITE 3.0 3.0 3.0 MX Cement: EQIOM CEM I 52.5 28.0 28.0 28.0 N Total 100.0 100.0 100.0

[0083] The mechanical tests were carried out on the material obtained after mixing after 24 hours at 20° C. in accordance with the standard ISO 604 for the compression tests and in accordance with ASTM D732 for the shear tests.

[0084] For sealing cables, a long setting time of about 10 minutes is necessary to make it possible to inject, into the drilling hole, a thixotropic product which does not flow out of the hole but which does not harden immediately, making it possible to introduce long cables (for example 8 meters long) before the product sets.

[0085] The implementation operations can involve one or two steps. When the implementation comprises only a single step, also referred to as “post grouting”, it consists in injecting the composition directly through the anchoring bolt after the bolt has been put in place in the drilled hole via a hollow bar and a self-drilling bolt or, alternatively, via an injection tube installed with the bolt in the case of a cable bolt, a solid bar or a glass-fiber profile. When the implementation is done in two steps, the process, also referred to as “pre-grouting”, consists of a first step of injecting the composition into the drilled anchoring orifice and then a second step of inserting the anchoring elements, the bolts, the cable and the fibers. With preference, the injection operation is carried out from the bottom of the drilling hole, at which the orifice of the injection tube is inserted so as to be gradually extracted while the composition is being injected, such that the composition is injected into the drilled anchoring hole in a way which limits the risk of bubble formation.

[0086] In table 3, use was made of a component A containing less reaction catalyst with a reaction time of about 10 minutes. The mixture E0872001 uses a combination of the isocyanate prepolymer, the cement and the plasticizer, by contrast with E0872002 which contains an isocyanate, plasticizer and cement, or E0872003 which contains just an isocyanate and cement. Better mechanical properties are clearly observed for the mixture E0872001. Similarly, a much smaller degree of brittleness (cf. photos of FIG. 1) is observed for E0872001 than for E0872002 or E0872003. The mechanical results are indicated in table 3.

TABLE-US-00003 TABLE 3 Test E0872001 E0872002 E0872003 Component A A0832001 A0832001 A0832001 Component B B0832001 B0832002 B0832003 Ratio 1/2 1/2 1/2 component A/ component B Compressive 18.6 13.2 2.7 strength at 10% strain (MPa) Compressive 24.5 11.7 0.0 strength at 20% strain (MPa) Compressive 21.9 10.1 0.0 strength at 30% strain (MPa) Shear strength 7.0 3.1 2.7 (MPa)
Table 3 (Mechanical Results for Product with Setting Times of 10 Minutes)

[0087] Implementation of the composition according to the invention: In some embodiments, the components will be implemented using positive-displacement pumps such as for example piston pumps, gear pumps, pigtail (Archimedes-screw) pumps, etc, or with any other equipment that enables the injection to be performed while preserving the volumetric ratio between the various components, such as for example follower plates used for viscous or pasty products. The pump(s) used will make it possible to inject the mixture of the various components into the anchoring hole via an injection tube or directly by, that is to say through, the anchoring bolt comprising a hollow nut, such as in the context of implementation of “post grouting” type. The various components are mixed during the injection using a static or dynamic mixer. As an alternative, the various components are mixed after injection, by rotationally introducing the sealing pin, thus ensuring that the components are mixed, such as within the context of implementation of “pre-grouting” type. In each case, mixing the components generates the chemical hardening reaction that makes it possible to seal the anchoring bolt, the sealing pin or the cable in the ground.

[0088] The process by injection requires compositions which have viscosities which will be controlled and can be used over a temperature range of 5 to 50° C. and generally of 10 to 35° C. This parameter is important since it determines the quantity of cement, fillers and rheological agent that can be used in the component B and the quantity and the type of MDI prepolymer and plasticizer. This viscosity will be of 50 to 1500 mPa.Math.s and preferably 200 to 1100 mPa.Math.s at 20° C. for the component A and of 50 to 3000 mPa.Math.s and preferably 150 to 1500 mPa.Math.s at 20° C. for the component B. The products may contain rheological additives which act on the viscosity, the values are preferably measured using an MS Z3 DIN system at an angular speed of 700±100 (1/s) corresponding to a rotational speed of 500±100 rpm, making it possible to omit these rheological effects that are especially present at low speed (between 0 and 200 rpm).

[0089] The use of an MDI prepolymer improves the mechanical performance, such as shear strength and brittleness, but adversely affects the pumpability because of its higher viscosity than a polymeric MDI. The combined use of an MDI prepolymer and a plasticizer makes it possible to control the viscosity of the component B while still ensuring better mechanical properties.

[0090] Of course, the invention is not limited to the embodiments described. Modifications remain possible, in particular from the point of view of the constitution of the various elements or by substitution of technical equivalents, in particular chemical equivalents, without thereby departing from the scope of protection of the invention.