WO1999001398A1

WO1999001398A1 - Method for sealing components by injecting gel-forming water glass solutions

Info

Publication number: WO1999001398A1
Application number: PCT/EP1998/003830
Authority: WO
Inventors: Joachim Sass
Original assignee: Henkel Kommanditgesellschaft Auf Aktien
Priority date: 1997-07-02
Filing date: 1998-06-23
Publication date: 1999-01-14
Also published as: DE19728088A1

Abstract

The invention relates to a method for cleaning up components, specially fissured masonry or concrete, wherein at least one hole is made in the masonry or concrete, which cuts the fissure (s) and a packer is introduced into said holes so that a cavity remains in front of the packer, which is connected to the fissure(s), and a gel-forming liquid is injected from the packer into the hollow cavity in front of the packer and into the fissure(s). The inventive method is characterized in that a water glass solution is used as a gel-forming liquid, which is mixed with esters or with an aqueous hardening solution in the packer itself, before being fed into the packer or once it has exited from said packer. Said liquid consists of one or several components: alkali metal aluminate, alkaline earth cation salts, acidic water-soluble salts, glyoxal, organic acids or the compounds thereof, which are capable of bonding hydroxide ions.

Description

"Process for sealing components by injection of gel-forming water glass solutions"

The invention relates to a method for sealing components such as cracked masonry or concrete, wherein the cracks are filled with a gel-forming water glass / hardener solution.

Cracks in masonry or concrete can cause water and possibly pollutants to penetrate inside buildings. This danger exists, for example, with foundations that are intended to seal against backwater or pressurized water. Another example are dams, where cracks can allow water to penetrate inside the building. On the other hand, masonry or, in particular, concrete is often used to enclose liquids and in particular water and to prevent these liquids from escaping undesirably or from penetrating into the ground. An example of this are hydraulic structures such as locks or shipping canals, especially if they run above the surrounding level. Other examples are the concrete cups, which are attached under and around tanks with environmentally hazardous liquids, as well as the concrete sealing of filling points for trucks or tank wagons, which should prevent the liquids to be filled from leaking into the soil. Finally, masonry or walkable sewer canals are to be mentioned, in which a crack education can lead to waste water containing pollutants in the surrounding soil and in the worst case in the groundwater.

Methods for the repair of cracks in, for example, masonry or concrete are known in practice. Holes are drilled in the cracks. Packers are used in these holes, through which hardening solutions are pressed. Such packers and associated presses are described, for example, in the company brochure "Building renovation systems: injection presses, packers and accessories" from Desoi GmbH, Gewerbestr. 16, D-36148 Kalbach. This company brochure also provides information on how these packers are to be placed. Similar injection systems are also described in the company brochure "The technological advantage with MC injection systems" from MC-Bauchemie, PO Box 23 03 09, D-45071 Essen. According to this company brochure, solutions of polyurethane resins or epoxy resins as well as cement suspensions can be used as injection liquids. These injection liquids have the disadvantage of longer and not exactly adjustable curing times. The resistance to microbiological attack is questionable with organic resins.

The invention has for its object to provide an improved method for the repair of cracked components, wherein a gel-forming liquid is pressed into the cracks. Injection solutions are to be used which form hydrogels after an adjustable hardening time in the range of a few minutes. This condition makes it necessary to find suitable combinations of gelling agents and hardening substances. Depending on the desired field of application, the gels can be present as elastic soft gels or as hard gels with higher solids content. The funds should be able to be used without any health risk and be in the ground behave as environmentally neutral as possible. For example, they should have the lowest possible C SB value and should not contain any aggressive substances, such as, for example, silicic acid.

This object is achieved by a method for sealing components, for example cracked masonry or concrete, whereby at least one hole is made in the component that cuts the crack or cracks, and a packer is introduced into the individual holes so that a packer is inserted in front of the packer Cavity remains, which has a connection to the crack or the cracks, and from the packer injected a gel-forming liquid into the cavity in front of the packer and into the crack or the cracks, characterized in that a water glass solution is used as the gel-forming liquid, which in the Packer itself, before feeding into the packer or when leaving the packer, is mixed with esters or with an aqueous hardener solution which contains one or more of the following components: alkali metal aluminate, salts of alkaline earth metal cations, acidic water-soluble salts, glyoxal, organic acids or their compounds that are able to bind hydroxide ions. This gel-forming liquid is also referred to below as an “injection solution”.

Accordingly, a hole is made near the damaged areas so that it cuts the crack or tears. A packer is inserted into this hole, which must be sufficiently wide, so that there is still an open connection between the crack and the hole.

The packer preferably consists of two tubular sleeves inserted into one another (FIG. 1). The inner tube sleeve (19) has an external thread for a flat nut (17) and an internal thread for receiving a compression nipple (16) a valve, for example a ball valve. At the lower end, this packer has an outer collar (21) on its inner tube as a stop for a piece of hose (20). The outer tube sleeve (18) stands on this piece of hose and is connected to the inner tube (19) at the upper end by a flat nut (17). When tightening this flat nut, the distance between the collar on the inner tube and the lower edge of the outer tube sleeve is shortened. As a result, the piece of tubing bulges out and lies against the inner wall of the drilling channel (11) in a form-fitting and sealing manner.

Such packers are known for the renovation of cracked masonry or concrete (compare the company brochure from Desoi GmbH quoted at the beginning). The figure shows a schematic drawing of such a packer, which is located in a laterally attached bore (11) (blind hole) which cuts a crack (14) to be compressed. FIG. 1 shows a conceivable application example of the renovation method according to the invention: concrete or masonry (15) is to be renovated here, which lies or rests on one side against the existing floor (12). The other side borders on air. The crack (14) is blocked on the air side, for example with a quick-setting adhesive mortar (10). This prevents the gel-forming water glass / hardening solution from escaping into the air space. At the other end of the crack, the solution for injection can penetrate into the soil, which increases the sealing effect (13). The solution for injection is pressed until a certain pressure to be specified builds up. The pressure should be adapted to the strength of the component. The end of the injection is indicated by an increase in pressure.

In the example shown, the packer has a single compression nipple. Accordingly, the water glass and hardener solution must be pressed together before being pressed into the nipple be mixed. The injection medium is pressed into the partially closed blind hole / crack cavity system via the nipple. Blind hole, crack and in some areas the adjacent soil material are filled. The packer preferably remains in the blind hole after the injection or is cut off with the cut-off wheel. The remaining hole and the rest of the packer are cleaned with mortar.

However, you can also use a packer that has two separate supply lines for the water glass and the hardener solution. Such a packer is shown in Figure 2. In this case, the water glass and hardener solutions only mix when they exit the packer into the borehole. Mixing can be improved by a suitably designed mixing nozzle at the outlet of the packer. In this embodiment it is ensured that no solution for injection hardens within the packer. In the simplest case, a disc (22) with two bores is sufficient, from which the two solutions emerge into the boring channel (11) and mix in the process.

Of course, it is possible and advisable to work with not just a single hole and a single packer, but several if the surface seals are required.

Sodium and / or potassium water glass solutions can be used as water glass solutions. Sodium water glass solutions are preferred for cost reasons. These also have a more favorable viscosity behavior than potassium water glass solutions. The water glass solutions which can be used for the process according to the invention preferably have a solids content in the range from 2 to 40% by weight, in particular from 5 to 25% by weight. Solids contents in the upper range are particularly preferred if a cavern has already formed behind the crack in the ground by washing out, which is to be filled with the gel resulting from the solution for injection. However, the solids content is limited by the viscosity of the solution and the gel formation that may take place too quickly. Solutions with a lower solids content are preferably used when the solution is to penetrate looser soil behind the crack. The water glass solutions preferably have a molar ratio of SiO 2: M 2 O, M = alkali metal (= modulus) in the range from about 2 to about 5. Modules at the lower limit of this range and below have the disadvantage that they describe very strongly alkaline water glasses. In the use according to the invention, this can result in a strong alkali entry into the soil and requires the use of larger amounts of hardening substances. Modules in the upper area describe silicon-rich water glasses that are less strongly alkaline and that can be made to gel with less hardener additives. With increasing module, however, the viscosity increases with the same solids content of the solution, so that pumping around these water glass solutions becomes increasingly difficult. Water glass solutions with modules in the range from about 2.7 to 4.2 represent a good compromise between the different requirements and are therefore preferred.

A large number of hardener substances which convert an alkali metal silicate solution into a hydrogel are known. Their effect can consist in the fact that hardener components together with silicate ions form sparingly soluble precipitates which convert the water glass solution into a gel. Examples of these are alkali metal aluminate solutions, for example sodium aluminate solutions, which form an aluminosilicate gel when mixed with water glass solution. Alkaline earth metal cations react in a similar way, in which the precipitation of poorly soluble alkaline earth metal silicates causes gel formation cause. On the other hand, the gel formation mechanism can also be based on the fact that the hardening substances bind hydroxide ions of the alkaline water glass solution. This lowers the pH value of the silicate solution, which leads to the precipitation of gel-forming silica. Water-soluble salts that still contain acidic hydrogen ions act in this way. Examples of such acidic water-soluble salts which can be used as hardeners in the sense of the invention are hydrogen phosphates, dihydrogen phosphates, hydrogen sulfates and / or hydrogen carbonates. Hydrogen carbonates from the last group are particularly suitable.

However, organic acids or their compounds which are capable of binding hydroxide ions can also be used as hardening substances which lead to the formation of silica gels from water glass solutions by binding hydroxide ions. Substances of this type come into question if the resulting C SB content of the injection solution is not considered to be problematic for the soil that may be present. Examples of such compounds are carboxylic acid esters or carbonic acid esters, from which the free acid, which in turn binds hydroxide ions, is formed by hydrolysis in the alkaline water glass solution. In order to limit the COD load, esters of lower alcohols, in particular ethyl esters, are preferably used. Alternatively, esters of polyhydric alcohols with short-chain carboxylic acids can be used, for example acetic acid esters of glycol or glycerin. Glycerol triacetate is a preferred example. Glyoxal, which due to its low molecular weight leads to a particularly low COD load, can also be considered as the preferred hardening substance. Its effect is based on the fact that after a certain time it is rearranged in the alkaline water glass solution to hydroxyacetic acid, which in turn binds hydroxide ions. Hydroxyacetic acid is a naturally occurring substance whose biodegradation poses no problems. Mi Mixtures of different organic hardening substances, for example a mixture of glycerol triacetate and propylene carbonate, can lead to particularly favorable gel formation times.

If an alkali metal aluminate solution is used as the hardening solution, its concentration and amount are preferably chosen such that the SiO 2: Al 2 O 3 molar ratio in the mixed water glass / hardening solution is in the range from about 5 to about 100.

The concentrations of the water glass and hardener solution and their mixing ratio are preferably adjusted so that the ratio of the solids content of the water glass solution to the active substance content of the hardener solution is in the range from about 100: 2 to 100: 100 and that the total solids content of the mixed water glass and hardener solution is in the range between about 2 and about 50% by weight. Weight ratios of the solids content of the water glass solution to the active substance content of the hardener solution in the range from about 100: 2 to about 100: 50 are preferred for hard gels, and weight ratios of about 100: 10 to about 100: 100 are preferred for soft gels. In the case of solutions of salt-like hardeners, the active substance content of the hardener solution is understood to mean the solids content. In the case of organic hardeners, in particular those which are liquid at room temperature, this means the proportion of the organic component which is 100% in the case of pure esters. The ratio between the solids content of the water glass solution and the active substance content of the hardener solution allows the time until gel formation to occur. The lower this ratio, the faster the gel formation occurs. The time until gel formation also depends on the module of the water glass solution and the chemical nature of the hardener solution and must be determined experimentally for the respective combination. The time until can be varied by varying these parameters adapt to the desired processing time for gel formation. For this purpose, it can be advantageous, for example, to use a combination of different hardeners which differ in their reaction time. An example of this is the combination of the rather slow-reacting glyoxal with the rather fast-reacting sodium bicarbonate. In general, gel formation can be accelerated by using acidic salts when using esters as hardeners.

Regardless of the hardener substance chosen, the concentrations of the respective solutions are chosen such that the water glass / hardener solution after mixing has an SiO 2 concentration in the range from about 1 to about 30% by weight. SiO 2 contents of approximately 5 to approximately 10% by weight are preferred for soft gels and approximately 20 to approximately 30% by weight for hard gels. At lower concentrations, gel formation is no longer guaranteed; at higher concentrations, processing becomes increasingly difficult due to the high viscosity and possibly very rapid gel formation. Concentrations at the lower end of the range are advantageously chosen, however, if the cracks are narrow and / or the injection solution is to penetrate less porous soil. Concentrations in the upper range are preferred when the cracks are about 1 to about 5 mm wide. With smaller crack widths, thinner injection solutions are preferred.

The viscosity of the mixed water glass / hardener solution at the processing temperature should be in a range such that the solution can penetrate well into the cracks and, if necessary, underneath the soil or cavities. Viscosities in the range from about 1 to about 300 mPa.s (determinable according to Brookfield) are favorable. Viscosities less than 200 mPa-s, for example in the range from 2 to 100 mPa-s, are particularly favorable. The viscosity depends on the concentration and the modulus of the Water glass solution. It is known that high modules and high concentrations cause high viscosities.

The control of the supply of the water glass and the hardener solution in the packer is particularly easy to regulate if the concentrations of the two solutions are set such that the same volume parts of the two solutions must be mixed with one another. Depending on the packer design and pump design, other volume ratios are also possible. The technically realistic range of volume ratios is between approximately 10: 1 and approximately 1: 1. In principle, the water glass and hardener solutions can be mixed first and then fed into the packer via a single hose line. However, it is difficult, on the one hand, to avoid gel formation in the hose line and, on the other hand, to achieve rapid gel formation after injection of the solution into the damaged area. In terms of processing technology, it is therefore easier, albeit more complex in terms of equipment, to feed the water glass and hardener solution through separate hose lines into the packer and to mix them only in the packer itself or preferably immediately after it leaves the packer. Of course, this requires an appropriate construction of the packer, as shown in Figure 2, for example.

The water glass / hardener solutions to be used according to the invention have the advantage of being largely environmentally neutral even in the unreacted state. The resulting gels are elastic soft or hard gels. Solid gels (hard gels) are particularly resistant to deformation due to drying out and show less shrinkage. They are largely insensitive to changes in building moisture. The systems of water glass and hardener solution according to the invention have the advantage that the time interval until gel formation and thus the processing time can be set in a reproducible manner. After the gel formation time has elapsed, gel formation takes place reliably and quickly. This ensures high processing reliability with a short cycle time. It is not necessary to heat the solutions for injection. The gels cure reliably at the temperatures commonly encountered.

B e i s p i e l e

A number of water glass / hardener systems are described below which lead to the gel formation times sought according to the invention. All percentages mean percentages by weight.

The following can be used as water glass solutions (commercial products from Henkel KGaA, Düsseldorf):

Na water glass HK 30 with 22.39% Siθ2 and 5.83% Na2θ weight ratio Siθ2 to Na2θ = 3.84 Na water glass 37/40 with 27.01% Siθ2 and 7.99% Na ₂ O weight ratio Siθ2 to Na2θ = 3.38 Na water glass 43/45 with 31.32% Siθ2 and 10.10% Na2θ weight ratio Siθ2 to Na2θ = 3.10 Na water glass 48/50 with 33.36% Siθ2 and 12.10% Na2θ weight ratio Siθ2 Na2θ = 2.76 K water glass 40 with 27.53% Siθ2 and 13.17% K2O weight ratio Siθ2 to K2O = 2.09

The last three types of water glass are very viscous. They have to be diluted with water in order to obtain well pumpable solutions. Demineralized water was generally used as water. Examples of injection solutions:

The water glass and hardener solutions were quickly mixed together in a beaker and the time until gel formation (solidification of the solution) was determined.

Injection solutions for soft gels:

Injection solutions for hard gels

The following were also used as auxiliary substances:

Glucopon ^R 215 CS: Cg-Cιo-alkyl-l, 5-glucoside (commercial product from Henkel KGaA) as a 20% solution Triton ^ - BG 10: sugar-fatty alcohol acetal (commercial product from Union Carbide) as 17.5% Solution With the exception of Example 9, the gel formation experiments were carried out at 23 ° C.

1) Dilution before weighing: 534.0 g of K water glass 40 were diluted with 16.6 g of water. A solution with 26.73% SiO 2 and 12.79% K2O is obtained. 100 g of this were used for Example 8.

2) The example shows a water glass / hardener system that can be injected in a volume ratio of 8: 1.

Example 10

Water glass solution: 100.0 g Na water glass 37/40

0.2 g Triton BG 10 together 74.2 ml

Hardener solution: 7.2 g glycerol triacetate 3.6 g propylene carbonate together 9.2 ml

The water glass and hardener solution of the composition mentioned were mixed rapidly in a volume ratio of 8: 1 (the time until gel formation is 150 seconds). 85 g of the mixed solution were immediately mixed intensively with 300 g of F 32 quartz sand, so that all the air could escape. A solid body was obtained which showed very little shrinkage. The example shows that the formation of a stable solid body can be expected when the solution for injection enters the ground. Reference list

10 = adhesive mortar

11 = drilling channel

12 = floor in contact

13 = injected soil

14 = crack

15 = concrete / masonry

16 = compression nipple

17 = flat nut

18 = tube sleeve

19 = pipe sleeve with thread

20 = rubber hose 21 = collar

22 = disc with 2 holes

Claims

claims

1. A method for sealing components, wherein at least one hole is made in the component that cuts the crack or cracks, introduces a packer into the individual holes so that a cavity remains in front of the packer that connects to the crack or the Has cracks, and from the packer a gel-forming liquid is injected into the cavity in front of the packer and into the crack or the cracks, characterized in that a water glass solution is used as the gel-forming liquid, which in the packer itself, before feeding into the packer or at Leaving the packer is mixed with esters or with an aqueous hardener solution containing one or more of the following components: alkali metal aluminate, salts of alkaline earth metal cations, acidic water-soluble salts, glyoxal, organic acids or their compounds which are able to bind hydroxide ions .

2. The method according to claim 1, characterized in that the water glass solution is a sodium and / or potassium water glass solution with a solids content in the range from 2 to 40 wt .-% and a module (= molar ratio SiO 2: M2O, M = alkali metal) in the range from 2 to 5.

3. The method according to one or both of claims 1 and 2, characterized in that the acidic water-soluble salts are selected from hydrogen phosphates, dihydrogen phosphates, hydrogen sulfates and / or hydrogen carbonates.

4. The method according to one or both of claims 1 and 2, characterized in that the esters are selected from carboxylic acid esters and carbonic acid esters.

5. The method according to one or both of claims 1 and 2, characterized in that the hardener solution contains alkali metal aluminate in an amount that the molar ratio SiO 2: Al 2 O 3 in the mixed water glass / hardener solution is in the range from 5 to 100.

6. The method according to one or more of claims 1 to 5, characterized in that the ratio of the solids content of the water glass solution to the active ingredient content of the hardener solution is in the range from 100: 2 to 100: 100 and that the solids content of the mixed water glass and hardener solution is in the range is between 2 and 50% by weight.

7. The method according to one or more of claims 1 to 6, characterized in that the water glass / hardener solution after mixing has a SiO 2 concentration in the range of 1 to 30 wt .-%.

8. The method according to one or more of claims 1 to 7, characterized in that the water glass and the hardener solution are fed through separate feed lines into the packer and mixed within the packer or when leaving the packer. A method according to claim 8, characterized in that the gel time of the mixed water glass / hardener solution is in the range of 15 seconds to 5 minutes.