SI9600227A - Injection composition and also with same produced injection suspensions - Google Patents

Abstract

An injection medium, as a dry mix for producing an injection suspension for sealing and/or permeability redn. of earth, rock and/or constructions against fluid (esp. water and/or gas), contains a mineral binder (esp. an ultra-fine binder), a stabiliser, a plasticiser and opt. other conventional additives such as a setting accelerator, an injection aid and a water retention agent, the stabiliser being an organic thickening agent and the mix contg. an inert ultra-fine filler. Also claimed is an injection suspension produced by introducing the above injection medium components into water with a water/solids ratio of above 3.5 and pref. with a water/binder ratio of above 7.

Description

DVCKERHOFF AG

Biebricher Strasse 69

65203 Hiesbaden

Germany

INJECTION INSTRUMENT AS ALSO 2 USE OF INJECTION PRODUCT MANUFACTURED SUSPENSION

The invention relates to a grout as well as the use of a grout designed to seal and / or reduce the permeability of floors (and / or rocky rocks) and / or rocks and / or structures to penetrate with fluids, in particular water and / or gases. The invention is particularly useful for sealing the bottom of a sandy base of a construction pit and for sealing cracks and cracks in a rock.

For low-rise civil engineering projects, groundwater penetration into the construction pit should be prevented. Typically, the ground water supply is interrupted by vertically securing a construction pit with a sealing or thin wall. Subsequent penetration of groundwater from the substrate is interrupted by injections into the ground with f

injectable solutions or injectable suspensions whereby it is injected in a specific solution.

The injectable suspension solids are supposed to have a grain size that allows penetration into the finest cavities. In addition, the suspension for injection must ensure that, after the so-called Time of Maturation, the permeability of water-injected soil substances is at least sufficiently reduced. There should be no environmental hazard from the injection. The injection procedure should be technically easy to use and economically feasible.

Injectable solutions are known to be used in the form

2 or finest cement so-called soft gels suspensions j.

Soft gels consist of aqueous glass solutions and some hardening component. The disadvantage is that after the addition of the hardener, the solution must be injected within a very short period of time, otherwise reactions will occur which increase the viscosity of the injection suspension so that injection is no longer feasible. In addition, removal of waste residual suspensions is problematic. A particularly significant drawback, however, is the undesirable high long-term intake of alkali in soil water. Therefore, there is a growing need for such soft gels to be excluded as an injection.

Suspensions of the finest cements consist of aqueous suspensions of the finest cements with very high fines, to which sodium bentonite is mostly added for stabilization. Suspensions of the finest cement are easy and safe to process. The finest cements consist mainly of finest ground slag sands and initiators and / or Portland cements which, upon addition of water, occasionally react alkaline with the release of water due to the release of Ca (OH) 2 · Ca (0H) 2 from groundwater CO2 into the limestone. Accordingly, the injection t

the process of suspending the finest cement to the environment spares j i v.

Sodium bentonite is a highly swollen clay which decomposes into the finest particles in aqueous suspension. These finest sodium bentonite particles give suspensions at rest a liquidCriost boundary that prevents sedimentation of solids. In the presence of hydrating cement, sodium bentorites tend to change the ionic charge resulting in unwanted agglomeration; the high finoCa of the output components cannot be fully utilized. In addition, the storage stability of the bentonite-finest cement sodium mixture is very limited.

A further disadvantage with the sodium bentonite stabilized suspensions of the finest cement is that the Green injection effects are reduced in the saline soils. In addition, suspensions of sodium bentonite with the finest cement with high water-binder tend to sink into the substrate, which can usually be prevented only if the proportion of sodium bentonite increases significantly. Increasing the sodium bentonite content also increases the risk of agglomerations.

It is an object of the invention to provide a mixture of fine particles having at least one binder and injectable suspensions thereof, which is easy to process and provides optimum sealing or sealing. reducing permeability and are, as a dry compound, stable during storage. This problem is solved by claims 1 and 15 as well as 16. Very suitable further development steps of the invention are indicated in the sub-claims.

The composition of the invention is sodium bentonite free and has few binders. In addition to the essential basic components, it contains binders, especially the finest binders, plasticizers and promoters, some substantially inert, mineral filler, of the finest particle-forming particles and at least one organic thickener, e.g. at least some polysaccharide, which acts as a sealant and as a stabilizer. Inert according to the invention means that the filler does not react, or reacts only insignificantly or. is reactionary slow. It may have low latency or porosity.

FinoCa finest binders are known. Polysaccharides are described, for example, in Ulmanns Enzyklopadie der technischen Chemie, 4. Neubearbeitet und erweiterte Auflage, Bd, 19, page 233 et seq. Particularly suitable stabilizers are, for example, cellulose ethers such as hydroxyethyl cellulose (HEC), carboxymethylhydroxyethyl cellulose (CMHEC), and carboxymeters 1 cellulose (CMC), and in particular xanthan- or welanum-based biopolymers. The effect of these materials, especially the polymer based on welan gum or we1an gum alone or synthetic polymeric thickeners, such as acrylic acid based, can be enhanced by synergy with cellulosic products such as HEC, CMHEC and CMC or other natural thickeners such as guar flour and carob kernels.

DE 43 39 386 Al discloses liquid media with sodium bentonite for flushing holes and filling seismic shallow openings which additionally contain selected polysaccharides in addition to bentonite and cement. Polysaccharide is expected to improve sedimentation properties and filter cake formation. In addition, known suspensions of cement and water containing polysaccharide in combination with some superpl astif icator (Applications of Rheological Modifiers and Superplasticizers and Cementitious Systems, CB Skaggs, WGRaki tsky, and SF Wh i taker, Superplasticizers and Other Chemical Admixtures and Concrete, Proceedings of the 4th CANMET / ACI International Conference, Montreal, Canada, October 1994). In the known mixtures, in the first case, only the purpose-oriented construction of a sealing filter cake is carried out, in the second case, the sealing is described only with the binder itself. The combined effect of the components of the invention is thus disregarded. According to the present invention, this can only be achieved by using the finest binders in conjunction with the finest fillers and half isaccharides, the mixture being free of sodium bentonite.

The compositions of the invention are stable during storage and the resulting suspensions are long-term sedimentation-stable and can be used without hindrance, even in saline soils. The high fineness of the components can be fully utilized, especially when using the finest binders. Formation of agglomerates with a chemical or chemical-physical change

5ene ingredients are excluded. The loss of filtrate water, measured by API RP 13B test, is small; the filter circuit does not form. Surprisingly, the water permeability value of DIN 18130 of the injected sand layer remains drastically reduced when using a filler whose solids content of the mixture is preferably greater than 50% (by weight).

Whence the specific effect of the combination of the stabilizer with the solids system results, is unknown. Solids with water / solid values preferably greater than 5 in the suspensions made, theoretically considered, cannot fill relatively large interstices, for example in sandy soils or. in the cracks in the cracked rock. It is very likely that the combination of ingredients with the tabiizer / finest filler and binder, especially the finest binder, frame or skeleton in the rooms of the sand or pores. between the edges of crevices of a rock that rests on the walls of grains or cracks and divide the pore spaces into smaller pores so that water entry and penetration can be prevented to the greatest extent possible. The stabilizer, among other things, has the task of keeping the solid components (filler and cement, especially the finest cement) in the cracks or. in wedge spaces between grains of sand until crystals or. crystallites of the phases of silicate hydrates, which t

they grow from the cement grains radially into the room, the filler grains do not permanently mesh with one another and merge with the walls of the room.

Stone flours containing clay and clay flours may be used as the finest filler, insofar as the clay component behaves mainly inert with calcium ions, such as calcium bentonite, kaolin and illite clays. Unlike sodium bentonite, which acts as a tabiizer, calcium bentonite, illit and kaolinite at high water / solid values do not contribute to the suspension support or only insignificantly. They do not significantly contribute to the development of strength, which is why they are used as inert-6 finest fillers in terms of i2um.

The finest fillers should also include, for example, fly ash, and / or certain ppcas reacting flours of slag sands and / or certain rock flours, such as volcanic tuff or float or the like, which over a longer period of time make a small contribution to strength which, however, is invisible for the short-term use indicated.

The composition of the present invention seals pores associated with improved environmental friendliness over other substances due to the crucial reduction of the released alkali and alkaline earth ions.

The compositions according to the invention for the manufacture of a suspension suspension consist essentially of:

- components A: binders in particular of the finest binder, preferably of the finest cement;

- components B: the finest filler, in particular the finest stone flour;

- C components: polysaccharides in the form of a polysah a r i d a;

- components 0: plasticizer;

i

- Components E: Accelerator.

In addition, other common additives, such as injectables or water retention agents, may be present.

Preferred mixtures contain the following ingredients:

- component A: 80 to 20%, in particular 70 to 30%, preferably 60 to 40 I (weight percent);

- component B: 20 to 80%, in particular 30 to 70%, preferably 40 to 60% (by weight);

- component C: 0.05 to 2 t, in particular 0.2 to 1 Z (weight percent), defined by the sum of components A and B;

-7- component D: 0.1 to 3 in particular 0.2 to 1% (weight percent), defined, to the sum of components A and B;

- component E: 1 to 10%, in particular 2 to 6% (by weight), defined on the finest binder.

In particular, the finest cement is used, especially based on Portland cement or slag cement as a binder. Mixtures of the finest cement and the finest slag sand flour are also well suited. Stone flours, especially limestone flours, with finesCo 5 pm <x <40 pm, are especially used as the finest filler. In addition to the preferably used finer and finer components from 1 to 40 pm, substances from 40 to ca. 90 pm. The plasticizer is, in particular, sulfonated naphthalene ~ formaldehyde condensate (PNS), and sodium sulphate is preferably used as an accelerating agent. The preferred stabilizer is welan gum.

The mixtures according to the invention are mixed in suspension by intensive mixing with water, whereby partial quantities may be added later at the construction site as a compound additive. The preference is given to a water / solid value above 3.5.

After maturation, the permeability of the layer injected with the mixture of the invention is at least moCrio reduced. The formulations of the invention have a very low solids content, with a very high water / solids value over 5 (corresponding to a water / binder value preferably over 10) satisfying the sealing requirements, such as sand or sandy soil layers. The suspension is also suitable for injections into cracks in the rock. Suspension stability is obtained by the addition of associative thickeners. The fincoCa of the finer binder or the finest filler depends on the type of soil to be injected and preferably lies in the grain size range above 5 pm and below 24 pm. Latent hydraulic binders with initiates - 8 secs or natural or artificial pozzolans (volcanic tuff, calcined clay, calcined kaolin or calcined rock flour or fly ash or silica powder) with the reaction partner are also considered the finest binders. Clay cement and conventional fine cements are also suitable. In this case, the initiators and / or the reaction partners are generally more refined cement, finest calcium hydroxide, sodium or potassium hydroxide, or sodium or potassium sulfate. The finest fillers can be used as mentioned above - also clay-containing stone flours and clay flours, insofar as the clay component behaves mainly inertly, such as calcium benton i tn i h, kaolin and illiterate clays. Injectable excipients are dispersant I, such as naphthalenformaldehyde condensate sulfonate or sodium polymethacrylate.

In the suspensions of the invention, the crystals of the hydrate phase of the binders, especially the finest binders, can apparently expand freely in the space and develop together with the finer fill grains a kind of framework, thereby creating an auxiliary position for the polysaccharides. With the addition of saccharides and essentially inert finest fillers, this effect cannot be achieved. In the case of known mixtures of cement or cement. the finest cement and naphthium bentonite accumulate solids material on the surfaces of the grains of grains or on the surfaces of cracks in the rock, leaving a significant part of the space between the grains of sand and / or sand for free penetration. in the cracks. According to the invention, this space is not filled with inert material, because the amount of inert material is not sufficient, and a matrix structure is formed which has some very fine hole-like matrix material in the cavities. This effect of the components was not predictable. The invention can - as has already been done - be carried out with binders, in particular cements, conventional fines, as well as with the finest binders or. the finest cements, because in accordance with the invention it is essential that the premises or in the spaces of the pores to be sealed, construct the structure of the frame that is

-9 consisting essentially of crystals of calcium silicate hydrates and filler grains.

Claims (16)

1. Injectable agent as a dry mixture for the manufacture of a suspension for sealing and / or reducing the permeability of soil (fragile rocks) and / or rock and / or buildings against fluid penetration, in particular water and / or gases containing at least one mineral binder, 2 particular finer binders, at least one stabilizer, at least one plasticizer, as well as other conventional additives, such as at least one accelerating agent, some auxiliary injection and water retaining agent, wherein the stabilizer is at least one organic thickening agent and the mixture further has at least one substantially inert finest filler. An injection agent according to claim 1, characterized in that the binder is some of the finest binders, in particular some of the finest cement, in particular fine grains from 1 to 40 pm. An injection agent according to claim 1 and / or 2, characterized in that the finest binder is a mixture of the finest cement and the finest slag sand flour. t Injection according to claims 1 to 3, characterized in that the mineral binder is a cement and / or a mixture of cement and slag sand flour of ordinary fineness, e.g. 40 to ca. 90 pm. An injection agent according to one or more of Claims 1 to 4, characterized in that the finest filler is some fly ash and / or some slow-reacting slag sand flour and / or some specified rock flour, such as e.g. flour of volcanic tuff or float or the like. Injection according to claim 5, characterized in that the stone meal is limestone flour. 117. An injection agent according to claim 5 and / or 6, characterized in that the finoCa grain of the finest filler is between 1 p m <x <90 pm, in particular the finest filler between 5 p m <x <24 pm. An injection agent according to one or more of Claims 1 to 7, characterized in that the thickening agent is a poly sugar and d. An injection agent according to claim 8, characterized in that the polysaccharide is a cellulose ether. 10. An injection agent according to claim 8, characterized in that the polysaccharide is a xantangumium based biopolymer. An injection agent according to claim 8, characterized in that the polysaccharide is a bio-polymer based on we1an-gum, preferably welan-gum alone. 12. An injection agent according to one or more of claims 8 to 11, characterized in that it contains at least two of said t poly sugar and dov. An injection agent according to one or more of claims 8 to 12, characterized in that it further contains a natural thickener such as e.g. flour from guar and / or from the kernels of the carob. An injection agent according to one or more of claims 1 to 13, characterized in that it is composed as follows: - component A: binder, especially the finest binder, preferably the finest cement; - component B: the finest filler, in particular the finest stone flour; - component C: stabilizer in the form of a polysaccharide; - component D; plasticizer; - component E: solidifying agent. 15. An injection agent according to claim 14, characterized in that the mixtures are composed as follows: - component A: 80 to 20% (by weight), in particular 70 to 30% (by weight), preferably 60 to 40% (by weight); - component 8: 20 to 80% (by weight), in particular 30 to 70 3 (by weight), preferably 40 to 60% (by weight); - component C: 0.05 to 2 I (mass fraction), in particular 0.2 to 1% (mass fraction), defined by the sum of components A and B; - component D: 0.1 to 3 § (mass fraction), in particular 0.2 to 1% (mass fraction), defined by the sum of components A and B; - component E: 1 to 10? (mass fraction), in particular 2 to 6 I (mass fraction), defined to the finest binder. 16. Injectable suspension made from an injection agent according to one or more of claims 1 to 15, by introducing the ingredients of the injection agent into water with a water / solid value greater than 3.5. 17. Injectable suspension according to one or more of claims 1 to 16, in particular according to claim 16, made from an injection agent according to one or more of claims 1 to 16, by injecting the ingredients of the injection agent into water with a water value / binder over 7.