Classifications

• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
  • C09K17/00—Soil-conditioning materials or soil-stabilising materials
  • C09K17/40—Soil-conditioning materials or soil-stabilising materials containing mixtures of inorganic and organic compounds
  • C09K17/42—Inorganic compounds mixed with organic active ingredients, e.g. accelerators
  • C09K17/46—Inorganic compounds mixed with organic active ingredients, e.g. accelerators the inorganic compound being a water-soluble silicate
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B28/00—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements
  • C04B28/24—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements containing alkyl, ammonium or metal silicates; containing silica sols
  • C04B28/26—Silicates of the alkali metals

Definitions

• the invention relates to a method for improving the strength and impermeability of soils and engineering structures, particularly ducts and pipelines.
• soil and “engineering structure” are interprated in the broadest sense; these terms also covering various storage tanks, tunnels, natural and artificial cavities, rocks, etc., and soils surrounding them.
• Hungarian patent No. 153,975 describes a simple end rapid method for improving the strength and impermeability of soils and engineering structures.
• water glass or a water glass-containing medium is applied into or onto the article to be treated, and then the water glass is exposed to the effect of hydrogen fluoride, silicon tetrafluoride and/or hydrogen silicofluoride.
• Water glass when contacted with a gaseous fluoride, rapidly gellifies and completely plugs the leakages, cracks and cavities.
• this method is utilized to render underground engineering structures (such as ducts or storage tanks) water-tight, it is an additional advantage that water glass which enters the soil through the cracks solidifies as well, improving thereby the embedding of the structure and strengthening the surrounding soil.
• Fluoride gases have the additional advantage that they improve the corrosion resistance of concrete and reinforced concrete elements.
• gel-forming polymers Owing to the ir high average molecular weight, gel-forming polymers, even in small amounts, increase the viscosity of the starting water glass solution to such an extent that the resulting mixture is very difficult to handle, its application and the removal of the excess involves numerous technical problems. Sometimes the required amount of polymer cannot be introduced into the water glass solution, since a very thick, honey-like mixture is formed, which cannot be applied onto the article to be treated with the injecting apparatuses available. Gel-forming mixtures with appropriately low viscosity contain generally a rather small amount of polymer, thus the elasticity and ⁇ wel lability of the resulting gels still remain insufficient .
• the invention relates to a method for improving the strength and impermeability of soils and engineering structures by forming a hydrogel composed of silicic acid and a cross-linked swellable organic polymer in or on the soil or structure treated. According to the invention one proceeds in such a way that an aqueous solution of a silicic acid gel precursor is contacted with a water- soluble gel-forming vinyl monomer in the presence of
• aqueous solution of a precursor of silicic acid gel e.g. an aqueous solution of water glass with a water-soluble gel-forming vinyl monomer in the presence of the components described above, the following chemical processes proceed simultaneously:
• silicic acid gel forms from its precursor upon the effect of the polycarboxylic acid. Since these chemical processes take place in parallel, and all of the intermediates formed in the process interact with one another, a gel is formed in which the organic and mineral parts are amalgamated. She visual appearance of the resulting gel clearly differs from that of the gels obtained according to Hungarian patent applications Nos.
• silicic acid gel precursors ere the various water glasses (sodium silicate , potassium silicate , etc.) , but water-soluble silicones and poly silicates, such as those commonly utilized for preparing moulds, can also be applied.
• water-soluble gel-forming vinyl monomers the following are to be mentioned: acrylic acid, me thecrylie acid, itaconic acid, maleic acid, fumaric acid, water-soluble salts and esters of these acids, acryl amide, methacryl amide, etc.
• cross-linking agents for the organic polymer e.g. aldehydes (such as glyoxal, glutaraldehyde, etc.) or divinyl or trivinyl compounds (such as me thylene-bis-acrylsmide , ethylene-bis-acrylamide , triacryl triazine etc.) can be used .
• the cross-linking agents should be sufficiently water-soluble; their solubility in water should be at least 1 %.
• the redox catalyst system utilized according to the invention consists of an oxidizing and a reducing component. Any of the known redox type free radical initiator systems utilized conventionally in the production of vinyl polymers can be applied.
• the oxidizing component may be e.g. hydrogen peroxide, an alkali persulfate or a water-soluble organic peraoid
• the reducing component may be e .g. a water-soluble organic amine , a water-soluble salt of a metal with varying valencies, a thiosulfate , a bisulfite , etc.
• Polycarboxylic acids i.e.
• orgenic carboxylic acids with at least two earboxy groups which can be utilized in the process of the invention are e .g. tartario acid, sucoinic acid, citric acid, malic acid, ascorbic acid, etc.
• the silicic acid gel precursor to vinyl monomer weight ratio, calculated for the dry substances, may vary over a wide range, e.g. 10:1 to 1:10, preferably 5:1 to 1:1, most preferably 4:1 to 2:1. Due to economical reasons it is preferred to utilize the vinyl monomers in low amounts.
• the silicic acid gel precursor to polycarboxylic acid weight ratio, calculated for the dry substances, may vary within 1:0.5 to 1:0.06, preferably 1:0.2 to 1:0.08, most preferably about 1:0.1.
• the amount of the cross-linking agent, calculated for the.weight of the vinyl monomer present, may be 1:0.01 to 1:0.3, preferably 1:0.05 to 1:0.2.
• the amount of the redox catalyst system, calculated for the weight of the vinyl monomer present, may be 1:0.01 to 1:0.5, preferably 1:0.05 to 1:0.3. Within this range, the catalyst system contains the oxidizing and the reducing components preferably in about equimolar amounts.
• the gel-forming mixture may also contain one or more additives which modify the properties of the gel formed.
• additives may be the commonly known additives of cross-linked vinyl polymers, such as plasticizers, stabilizers, decomposition inhibitors, etc., of which melamine, urea, monomethylol urea and thiourea are mentioned.
• the amounts of such additives, if present, may reach the amount of the vinyl monomer.
• the gel-forming mixture may contain one or more filling agent(s) generally applied in such compositions, such as asbestos, sand, fly ash, bentonite, etc.
• filling agent(s) generally applied in such compositions, such as asbestos, sand, fly ash, bentonite, etc.
• the amount of such filling agents is not critical and is restricted essentially by technological factors (e.g. stirrebility end viscosity of the mixture, ease of application, etc.).
• the individual components of the gel-forming mixture are admixed with one another in an appropriate sequence, determined by compatibility factors, directly on the field of treatment (e.g. in the defective duct to be repaired). It is more preferred, however, to start with two pre-formed aqueous solutions and to admix them on the field of treatment.
• the compositions of the two aqueous solutions should be chosen so that both solutions remain stable and storable for a prolonged period, and no premature gel formation occurs.
• compatibility factors should be kept in mind:
• the silicic acid gel precursor must not be in a common solution with the polycarboxylic acid; - the two components of the redox catalyst system must not be in a common solution; and
• the aqueous solution of the vinyl monomer must not contain the oxidizing component of the redox catalyst system in free state (it may contain, however, the oxidizing component in masked, such as in complexed, form).
• the two aqueous solutions to be admixed on the field of treatment may have e .g. the following compositions: Solution “A”: silicic acid gel precursor (e.g. water glass), oxidizing component of the redox catalyst system, water; Solution “B”: water-soluble vinyl monomer, a cross-linking agent for the organic polymer, a polycarboxylic acid, reducing component of the redox catalyst system water; or Solution “A”: a silicic acid gel precursor, reducing component of the redox catalyst system water; Solution “B”: water-soluble vinyl monomer, a cross-linking agent for the organic polymer, a polycarboxylic acid, oxidizing component of the redex catalyst syste in masked form (e.g. complexed with uree), water.
• Solution “A” silicic acid gel precursor (e.g. water glass), oxidizing component of the redox catalyst system, water
• Solution “B” water-soluble vinyl monomer, a cross
• an acidic filling agent e.g. acidic fly ash
• an acidic filling agent must not be added to the solution of the silicic acid gel precursor.
• the method of the invention can be applied in the building industry for improving the strength and impermeability of soils and engineering structures.
• the individual components of the gel-forming mixture - presented preferably in two pre-formed aqueous solutions - are admixed with one another at the place of the treatment, e.g. in or on the soil or in or on the engineering structure.
• soil is to be solidified by the method of the invention, it is preferred to fill the two aqueous solutions into the tanks of a two-tank injector provided with a mixing head, end to inject the mixture of the two solutions into the soil to be treated.
• a duct is to be repaired by the method of the invention, it is preferred to use the so-celled "filling up" technique, where the two solutions are introduced after one another into the duct to be repaired.
• the method of the invention retains all the major advantages of the known methods disclosed in the cited patents and patent applications. Like these known methods, it provides a quick, safe and economical way for rendering soils or engineering structures strong and water-tight. Compared to the known methods, the method of the invention has the following additional advantages:
• the gel-forming mixtures are easy to handle, the treatment requires no specific equipment end no specific technological precaution;
• Solution "A” water 40.
• ml potassium persulfate 1.8 g thiourea 14 g concentrated aqueous water glass solution (dry substance : 37 w/w %) 50 ml
• Solution "B” water 80 ml methacrylic acid 16 ml tartaric acid 10. g me thylene-bis-acrylamide 0.5 g ferrous sulfate 0.5 g
• the two solutions are admixed with one another under intense stirring. A homogeneous, transparent gel is formed in 7.5 minutes.
• Solution "A” water 90 ml potassium persulfate 1.8 g thiourea 14 g
• Solution "B” water 80 ml acrylic acid 16 ml tartaric acid 10 g methylene-bis-acrylamide 0.5 g ferrous sulfate 0.5 g
• Solution "A” water 40 ml thiourea 14 g concentrated aqueous water glass solution (dry substance: 37 w/w %) 50 ml
• Solution "B” water 80 ml acrylic acid 16 g tartaric ecid 10. g methylene-bis-acrylamide 0.5 g
• Solution "B” water 80 ml acrylic acid 16 g succinic acid 10 g methylene-bis-acrylamide 2 g ferrous sulfate 1 g The two solutions are admixed with one another under intense stirring. A homogeneous, transparent gel is formed within one minute.
• Solution "A” water 70. ml potassium persulfate 0.9 g melamine 7 g concentrated aqueous water glass solution (dry substance: 37 w/w %) 25 ml
• Solution "B” water 80 ml methacrylie acid 16 ml tartaric acid 10 g methylene-bis-acrylamide 0.5 g ferrous sulfate 0.5 g
• the two solutions are admixed with one another under intense stirring.
• a homogeneous, transparent gel is formed in 120 minutes.
• Solution "A” water 16.
• ml potassium persulfate 0.8 g melamine 6
• concentrated aqueous water glass solution (dry substance: 37 w/w %) 20
• Solution "B” water 50 ml itaconic acid 4.
• ferrous sulfate 0.5 g methylene-bis-acrylamide 0.5 g citric acid 2 g
• Solution "A” water 19 ml concentrated aqueous water glass solution (dry substance: 37 w/w %) 80 ml triethanol amine 1 ml
• Solution "B” water 85 ml acrylic acid 15 ml citric acid 10 ml hydrogen peroxide complexed with urea 4. g methylene-bis-acrylamide 0.5 g
• the two solutions are admixed with one another under intense stirring.
• a homogeneous, transparent gel is formed in 18 minutes.
• the duct section to be treated is shown in Fig. 1.
• the duct section bordered by shafts 2 and 3 is cleaned appropriately and then blocked at the shafts with tube stoppers 1. Thereafter the closed duct section is filled up with solution "A" through shaft 2.
• Solution "A” is stored in tank 4.
• the pressure required to inject the solution into the leakages, cracks and cavities is provided by fillint up the shaft to the appropriate height.
• a solution height of about 1-2 m is maintained in shaft 2.
• the solution in the shaft is refilled, if necessary. After an appropriate period, generally about 10-20 minutes, the remainder of the liquid is pumped back from the duct section into tank 4 through shaft 2.
• solution "B” is introduced from tank 6 into the duct section through shaft 2. Again, the pressure required to inject the solution into the leakages, cracks and cavities is ensured by filling up the shaft to the appropriate height. The solution is refilled, if necessary. After an appropriate period, preferably when exfiltration ceases, the remainder of the liquid is pumped back into tank 6 through shaft 2, and the tube stoppers are removed. Thus repair is finished. If the results are to be checked by water-tightness tests using water. or air, this can b e done before removing the tube stoppers. However, this quality control can be avoided by leaving solution "B" in shaft 2 for an appropriate period. When the level of the solution in shaft 2 is not lowered within 15 minutes (or the extent of lowering is within the prescribed, tolerable limits), this indicates that the duct is appropriately water tight.
• Solutions "A” and “B” exfiltrated through the defects, inappropriate joints or cracks of the duct form stable gel 5 inside and/or in the surroundings of the duct treated. This enables not only the seepage lines of the duct to be blocked perfectly, but also the soil surroundi ng the duct to solidify and become water-tight. Consequently, the embedding conditions of the duct also improve to a great extent, which is a decisive factor in view of the stability and life span of duct networks.

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• Chemical & Material Sciences (AREA)
• Inorganic Chemistry (AREA)
• Engineering & Computer Science (AREA)
• Ceramic Engineering (AREA)
• Materials Engineering (AREA)
• Organic Chemistry (AREA)
• Soil Sciences (AREA)
• General Life Sciences & Earth Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Life Sciences & Earth Sciences (AREA)
• Structural Engineering (AREA)
• Soil Conditioners And Soil-Stabilizing Materials (AREA)
• Treatment Of Sludge (AREA)

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Publications (1)

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Family Applications (1)

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Cited By (3)

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Citations (10)

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• 1985
  • 1985-04-22 NL NL8520094A patent/NL8520094A/nl not_active Application Discontinuation
  • 1985-04-22 HU HU852153A patent/HU201108B/hu not_active IP Right Cessation
  • 1985-04-22 DE DE19853590726 patent/DE3590726T1/de not_active Withdrawn
  • 1985-04-22 WO PCT/HU1985/000027 patent/WO1986006400A1/en active Application Filing
  • 1985-04-22 GB GB8629182A patent/GB2186879B/en not_active Expired
  • 1985-05-02 DD DD85275896A patent/DD235685A5/de not_active IP Right Cessation
  • 1985-05-05 CS CS853245A patent/CS254340B2/cs unknown
  • 1985-05-06 YU YU00741/85A patent/YU74185A/xx unknown
  • 1985-05-06 IN IN348/CAL/85A patent/IN163304B/en unknown
  • 1985-05-16 ES ES543196A patent/ES8607454A1/es not_active Expired
  • 1985-05-31 FR FR8508235A patent/FR2580659A1/fr not_active Withdrawn
  • 1985-06-17 PL PL1985254032A patent/PL146456B1/pl unknown

Patent Citations (11)

Non-Patent Citations (1)

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