CA2463638C - Sealing composition and its use - Google Patents
Sealing composition and its use Download PDFInfo
- Publication number
- CA2463638C CA2463638C CA002463638A CA2463638A CA2463638C CA 2463638 C CA2463638 C CA 2463638C CA 002463638 A CA002463638 A CA 002463638A CA 2463638 A CA2463638 A CA 2463638A CA 2463638 C CA2463638 C CA 2463638C
- Authority
- CA
- Canada
- Prior art keywords
- sealing composition
- sealing
- silica sol
- gelling agent
- silica
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Classifications
-
- 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
-
- 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
- C09K3/00—Materials not provided for elsewhere
- C09K3/12—Materials for stopping leaks, e.g. in radiators, in tanks
-
- 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
- C04B2111/00—Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
- C04B2111/00474—Uses not provided for elsewhere in C04B2111/00
- C04B2111/00724—Uses not provided for elsewhere in C04B2111/00 in mining operations, e.g. for backfilling; in making tunnels or galleries
-
- 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
- C04B2111/00—Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
- C04B2111/00474—Uses not provided for elsewhere in C04B2111/00
- C04B2111/00732—Uses not provided for elsewhere in C04B2111/00 for soil stabilisation
-
- 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
- C04B2111/00—Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
- C04B2111/70—Grouts, e.g. injection mixtures for cables for prestressed concrete
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Ceramic Engineering (AREA)
- Materials Engineering (AREA)
- Organic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Inorganic Chemistry (AREA)
- Structural Engineering (AREA)
- Soil Conditioners And Soil-Stabilizing Materials (AREA)
- Sealing Material Composition (AREA)
- Consolidation Of Soil By Introduction Of Solidifying Substances Into Soil (AREA)
Abstract
The present invention relates to the use of a sealing composition for sealing rock or soil, wherein the sealing composition is obtainable by mixing a silica sol and at least one gelling agent, wherein the silica sol has an S-value higher than about 72%. The invention also relates to a method for cutting off a liquid flow in a leaking part or cavity by inserting the sealing composition. The invention also relates to a method for preparing the sealing composition and a composition obtainable from the method.
Description
Sealing composition and its use The present invention relates to the use of a composition for sealing rock and soil. The invention also relates to a method for cutting off the flow of liquid in a leaking part or cavity. The invention also relates to a method for preparing the sealing composition and a sealing composition obtainable from said method.
Background of the invention The requirements and performance of compositions used for sealing rock and soil have increased in the course of time. These requirements involve both improved environmental and technical aspects. Previously, various plastics and polymers involving toxic substances have been employed to seal water leaks in e.g. concrete walls, tunnels, or cavities formed on the back side of a concrete wall. Such sealing chemicals have in a number of cases caused contamination of groundwater and health problems to e.g.
construction workers handling them. However, attempts have been made to replace hazardous products with more environmentally adapted ones. New products have also been sought for to meet the recently imposed leakage restrictions. In some instances, water leakage levels below 1 litre/(min*100 meters) have been the upper threshold on constructions sites of tunnels. This have forced the suppliers to provide technically improved sealing products. US 5,396,749 describes a method for cutting off water flow by grouting whereby troubles due to water leakage and collapse of ground is prevented. The cut-off agent is prepared by mixing e.g. colloidal silica, inorganic salt, and a water-soluble urethane polymer.
However, the strength of these agents has shown to be insufficient in several applications, particularly where the agent during injection and gelling is exposed to a high water pressure. Especially unstable agents have during the ageing phase resulted in a fairly low long term strength. Sealing agents have also been used for sealing soil to prevent leakage of contaminants in subterranean areas like buried sources, waste dumps etc. US 5,836,390 describes a method of forming subsurface barriers where a viscous liquid comprising e.g. polybutenes, polysiloxanes, and colloidal silica is injected.
It is desirable to, provide an environmentally adapted liquid cut-off agent having a high long term strength, especially in the field of sealing rock, where the cut-off agents may be subjected to high water pressure from groundwater. It is also desirable to provide durable products which resist washout forces and having a low permeability, i.e.
impermeable to water and other liquids.
It is an object of the present invention to provide such products solving the drawbacks of the prior art referred to above.
1a The Invention In accordance with one aspect of the present invention, there is provided a use of a sealing composition for sealing rock or soil, wherein said sealing composition is obtained by mixing a silica sol having an S-value higher than about 72% and at least one gelling agent.
In accordance with another aspect of the present invention, there is provided a method for cutting off a liquid flow in a leaking part or cavity by inserting a sealing composition, said sealing composition being obtained by mixing a silica sol having an S-value higher than about 72% and at least one gelling agent, into the leaking part or cavity.
Background of the invention The requirements and performance of compositions used for sealing rock and soil have increased in the course of time. These requirements involve both improved environmental and technical aspects. Previously, various plastics and polymers involving toxic substances have been employed to seal water leaks in e.g. concrete walls, tunnels, or cavities formed on the back side of a concrete wall. Such sealing chemicals have in a number of cases caused contamination of groundwater and health problems to e.g.
construction workers handling them. However, attempts have been made to replace hazardous products with more environmentally adapted ones. New products have also been sought for to meet the recently imposed leakage restrictions. In some instances, water leakage levels below 1 litre/(min*100 meters) have been the upper threshold on constructions sites of tunnels. This have forced the suppliers to provide technically improved sealing products. US 5,396,749 describes a method for cutting off water flow by grouting whereby troubles due to water leakage and collapse of ground is prevented. The cut-off agent is prepared by mixing e.g. colloidal silica, inorganic salt, and a water-soluble urethane polymer.
However, the strength of these agents has shown to be insufficient in several applications, particularly where the agent during injection and gelling is exposed to a high water pressure. Especially unstable agents have during the ageing phase resulted in a fairly low long term strength. Sealing agents have also been used for sealing soil to prevent leakage of contaminants in subterranean areas like buried sources, waste dumps etc. US 5,836,390 describes a method of forming subsurface barriers where a viscous liquid comprising e.g. polybutenes, polysiloxanes, and colloidal silica is injected.
It is desirable to, provide an environmentally adapted liquid cut-off agent having a high long term strength, especially in the field of sealing rock, where the cut-off agents may be subjected to high water pressure from groundwater. It is also desirable to provide durable products which resist washout forces and having a low permeability, i.e.
impermeable to water and other liquids.
It is an object of the present invention to provide such products solving the drawbacks of the prior art referred to above.
1a The Invention In accordance with one aspect of the present invention, there is provided a use of a sealing composition for sealing rock or soil, wherein said sealing composition is obtained by mixing a silica sol having an S-value higher than about 72% and at least one gelling agent.
In accordance with another aspect of the present invention, there is provided a method for cutting off a liquid flow in a leaking part or cavity by inserting a sealing composition, said sealing composition being obtained by mixing a silica sol having an S-value higher than about 72% and at least one gelling agent, into the leaking part or cavity.
2 The present invention relates to the use of a sealing composition for sealing rock or soil, which sealing composition is obtainable by misdng a silica sol having an S-value higher than about 72% and at least one gelling agent.
The invention also relates to a method for cutf[ng oTf a liquid flow in a leaking part or cavity wherein the seaJing composition, obtainable by mixing a silica sol having an S-value higher than about 72% and at least one gelling agent, is inserted into a lealdng part or cavity.
The present (nverrfion also relates to a method for prep=ring a sealing composition, which'comprises mbcing a silica sol having an S-value hlgher than about 72% and at least one getting agent. The present invention also relates to a sealing composi'tion- oblsinable by this method.
It has been surprisingly found that a silica sol having a high S-value, i.e.
an S-vatue higher than about 72%, can Impart a high long term gel, strength to a sealing composition. The term "gel strengih as used herein is a measure of the shear and compnessive strength of the gelled sealing composition that develops with time. A high long temz strength provides a durable sealing. It has also been found that the sealing composition acoording to the present invention has a low permeabiiity, which indicates good sealing characterisfics.
The `S-value" characterises the extent of aggregation of the siiica pariides In the silica soi, i.e. the degree of aggregate or microgel formation. The S-vatiue of the silica sol has been measured and calculated according to the formulas given In l1er, R.K.
& Dalton, R,L in J. Phys. Chem. 60(1958), 955-957.
7he S-value Is dependent on the silica oontent; the viscosity, and the density of the silica sol. A high S-value indicates a low microgel conterrt. The S-vaiue repn3sents the amount of S[02 in percent by weight present In the d[sperse phase of the silica sol. The degree of microgel 'can be oonirolfed during fhe produatiart pnxess of sTca sols as further described In e.g. US 5368833.
According to one prefened embodiment of the invention, the S-value is higher than about 73 Yo, preferably higher then about 7496, even more preferably higher than about 75%. Prefierably, the S-value is lower than about 90%, and most preferably lower than about 85%.
The siiica sol comprises s~Tica paddes su.I#ably iiaving an averaqe pariide diameter ranging from about 3 to about 150 nm, pneferably frvrn about 12 to about 50 nm, and most preierdbiy from about 12 fio about 40 nm. Sulfabty, the silica partides have a specffic surface an3a of from about 20 to about 900, prefeMbly from about 40 to about 230, and
The invention also relates to a method for cutf[ng oTf a liquid flow in a leaking part or cavity wherein the seaJing composition, obtainable by mixing a silica sol having an S-value higher than about 72% and at least one gelling agent, is inserted into a lealdng part or cavity.
The present (nverrfion also relates to a method for prep=ring a sealing composition, which'comprises mbcing a silica sol having an S-value hlgher than about 72% and at least one getting agent. The present invention also relates to a sealing composi'tion- oblsinable by this method.
It has been surprisingly found that a silica sol having a high S-value, i.e.
an S-vatue higher than about 72%, can Impart a high long term gel, strength to a sealing composition. The term "gel strengih as used herein is a measure of the shear and compnessive strength of the gelled sealing composition that develops with time. A high long temz strength provides a durable sealing. It has also been found that the sealing composition acoording to the present invention has a low permeabiiity, which indicates good sealing characterisfics.
The `S-value" characterises the extent of aggregation of the siiica pariides In the silica soi, i.e. the degree of aggregate or microgel formation. The S-vatiue of the silica sol has been measured and calculated according to the formulas given In l1er, R.K.
& Dalton, R,L in J. Phys. Chem. 60(1958), 955-957.
7he S-value Is dependent on the silica oontent; the viscosity, and the density of the silica sol. A high S-value indicates a low microgel conterrt. The S-vaiue repn3sents the amount of S[02 in percent by weight present In the d[sperse phase of the silica sol. The degree of microgel 'can be oonirolfed during fhe produatiart pnxess of sTca sols as further described In e.g. US 5368833.
According to one prefened embodiment of the invention, the S-value is higher than about 73 Yo, preferably higher then about 7496, even more preferably higher than about 75%. Prefierably, the S-value is lower than about 90%, and most preferably lower than about 85%.
The siiica sol comprises s~Tica paddes su.I#ably iiaving an averaqe pariide diameter ranging from about 3 to about 150 nm, pneferably frvrn about 12 to about 50 nm, and most preierdbiy from about 12 fio about 40 nm. Sulfabty, the silica partides have a specffic surface an3a of from about 20 to about 900, prefeMbly from about 40 to about 230, and
3 most preferably from about 60 to about 220 m2/g. The density of the silica sol suitably is from about 1 to about 1.6, preferably from about 1.1 to about 1.5, and most preferably from about 1.2 to about 1.4 kg/m3.
The silica sol is suitably substantially monodisperse, i.e. having as narrow particle size distribution as possible. Suitably, the silica particles have a relative standard deviation of the particle size distribution lower than about 15% by numbers, preferably lower than 10%
by numbers, and most preferably lower than about 8% by numbers. The relative standard deviation of the particle size distribution is the ratio between the mean particle size by numbers and the standard deviation of the particle size distribution. The silica particles of the silica sol are suitably dispersed in water in presence of stabilising cations such as K, Na+, Li+, NH4+ or the like or mixtures thereof. However; also other dispersions such as organic solvents, e.g. lower alcohols, acetone or mixtures thereof may be used. The pH
of the dispersion suitably is from about 1 to about 12, preferably from about 7 to about 11. As long as the silica sol remains stable, i.e. substantially without any aggregation or gelation, a high silica content is preferred in the silica sol. This is beneficial in view of the superior technical performance of a highly concentrated silica sol and the reduced transportation cost thereof. According to one embodiment, the ingredients, i.e. the silica sol and the gelling agent are separately added to the applied point to be sealed. This may be performed e.g. by means of so called jet grouting, wherein the ingredients are mixed in situ, e.g. in the soil.
By the terms "silica soP" and "silica particle" are herein also meant to comprise e.g. aluminium-modified silica particles and sols, and boron-modified silica particles and sols. Boron-modified silica sols are described in e.g. US 2,630,410. Aluminium modified silica sols, sometimes also referred to as aluminate modified silica sols, can be prepared by adding an appropriate amount of aluminate ions, AI(OH)4 , to a conventional non-modified silica sol under agitation and heating. Suitably, a diluted sodium or potassium aluminate solution corresponding to an aluminium modification of from about 0.05 to about 2, preferably from about 0.1 to about 2 Al atoms/nm2 surface area of the silica particle is used. The aluminium-modified silica particles comprise inserted or exchanged aluminate ions, creating aluminosilicate sites having a fixed negative surface charge. The pH of the aluminium-modified silica sol can be adjusted, preferably by means of an ion exchange resin, suitably to a pH ranging from about 3 to about 11, preferably from about
The silica sol is suitably substantially monodisperse, i.e. having as narrow particle size distribution as possible. Suitably, the silica particles have a relative standard deviation of the particle size distribution lower than about 15% by numbers, preferably lower than 10%
by numbers, and most preferably lower than about 8% by numbers. The relative standard deviation of the particle size distribution is the ratio between the mean particle size by numbers and the standard deviation of the particle size distribution. The silica particles of the silica sol are suitably dispersed in water in presence of stabilising cations such as K, Na+, Li+, NH4+ or the like or mixtures thereof. However; also other dispersions such as organic solvents, e.g. lower alcohols, acetone or mixtures thereof may be used. The pH
of the dispersion suitably is from about 1 to about 12, preferably from about 7 to about 11. As long as the silica sol remains stable, i.e. substantially without any aggregation or gelation, a high silica content is preferred in the silica sol. This is beneficial in view of the superior technical performance of a highly concentrated silica sol and the reduced transportation cost thereof. According to one embodiment, the ingredients, i.e. the silica sol and the gelling agent are separately added to the applied point to be sealed. This may be performed e.g. by means of so called jet grouting, wherein the ingredients are mixed in situ, e.g. in the soil.
By the terms "silica soP" and "silica particle" are herein also meant to comprise e.g. aluminium-modified silica particles and sols, and boron-modified silica particles and sols. Boron-modified silica sols are described in e.g. US 2,630,410. Aluminium modified silica sols, sometimes also referred to as aluminate modified silica sols, can be prepared by adding an appropriate amount of aluminate ions, AI(OH)4 , to a conventional non-modified silica sol under agitation and heating. Suitably, a diluted sodium or potassium aluminate solution corresponding to an aluminium modification of from about 0.05 to about 2, preferably from about 0.1 to about 2 Al atoms/nm2 surface area of the silica particle is used. The aluminium-modified silica particles comprise inserted or exchanged aluminate ions, creating aluminosilicate sites having a fixed negative surface charge. The pH of the aluminium-modified silica sol can be adjusted, preferably by means of an ion exchange resin, suitably to a pH ranging from about 3 to about 11, preferably from about
4 to about 10. The aluminium modified silica particles suitably have an AI203 content of from about 0.05 to about 3 wt%, preferably from about 0.1 to about 2 wt%. The procedure of preparing an aluminium modified silica sol is further described e.g. in "The Chemistry of Silica", by Iler, K. Ralph, pages 407-409, John Wiley & Sons (1979) and in US
5 368 833.
The gelling agent suitably is an inorganic salt or acid, an organic salt such as sodium acetate, or acid such as acetic acid, but preferably an inorganic salt such as potassium chloride, calcium chloride, sodium chloride, magnesium chloride, magnesium sulphate, potassium iodide magnesium nitrate, sodium nitrate, potassium nitrate, calcium nitrate, and sodium silicate or mixtures thereof, preferably calcium chloride, sodium chloride or potassium chloride, and most preferably sodium chloride, sodium aluminate.
A gel time regulator such as an acidic triacetine (glycerine triacetate), diacetine, Glauber's salt (NaSO4*10H20), sulphuric acid, phosphoric acid or mixtures thereof may also be added to the sealing composition to control the gelation thereof.
The term "gel time", as used herein, means the amount of time elapsed from the moment of mixing the ingredients making up the sealing composition until the time when the sealing composition becomes too viscous to move or insert to a leaking point. The viscosity is suitably controlled in such way that a homogeneous moving front of the composition is formed moving in the direction of the point to be sealed.
Suitably, the initial viscosity of the sealing composition is from about 3 to about 100, preferably from about 4 to about 30 mPas. The gel time may easily be controlled by adjustment of the amount of gelling agent. Sometimes, instantaneous gelling without substantial dilution of the composition is necessitated to provide a gelled pressure-resisting sealing composition. A
short gel time may be optimal in cracks being relatively ground and where the risk for rapid dilution of the sealing composition exists. In some cases, it is essential especially in cracks that the gelling preferably should not start before the front of the inserted composition has fully penetrated the crack. Usually, the gel time ranges from about 1 to about 120, preferably from about 2 to about 60, more preferably from about 5 to about 40, and most preferably from about 5 to about 20 minutes in rock sealing. In soil sealing, the gel time usually ranges from about 5 minutes to about 24 hours, preferably from about 10 minutes to about 6 hours, and most preferably from about 15 minutes to about 3 hours.
The ingredients may be mixed at ambient temperature. The gelling agent is suitably added to the silica sol in an aqueous solution in a concentration from about 1 to about 30 wt%, preferably from about 2 to about 15 wt%. The silica sol, to which the gelling agent suitably is added, suitably has a silica content of from about 1 to about 70, preferably from about 20 to about 60, and most preferably from about 35 to about 50 wt%. A high silica content in the silica sol may in many instances be favourable due to reduced transportation costs of silica sol.
The silica content in the sealing composition suitably is from about I to about 60, preferably from about 15 to about 50, and most preferably from about 30 to about 45 wt%. A high silica content minimises shrinkage and maximises long term strength. The weight ratio of silica to gelling agent depends on the application and may vary depending on the application. Suitably, the weight ratio of silica particles: gelling agent is from about 400:1 to about 10:1, preferably from about 200:1 to about 20:1.
The gelling agent content in the sealing composition may vary depending on the type of gelling agent used. However, the gelling agent content suitably is from about 0.1 5'to about 10, preferably from about 0.2 to about 5 wt% of the composition. If sodium chloride is used as gelling agent, the content suitably is from about 0.2 to about 5, preferably from about 1 to about 3, and most preferably from about 1.5 to about 2 wt% of the composition. If calcium chloride is used as gelling agent, the content suitably is from about 0.1 to about 2, preferably from about 0.2 to about 1, and most preferably from about 0.25 to about 0.5 wt% of the composition.
According to a preferred embodiment, the sealing composition is inserted by injecting the silica sol separately to a leaking part or cavity whereby the sealing composition is formed in situ, e.g. in a crack of a rock or a cavity in the soil. The gelling agent may thus also be separately injected to the leaking part or cavity. This may be performed e.g. by injecting the sealing ingredients simultaneously, e.g. by placing injection nozzles for the silica sol and the gelling agent in parallel such that the gelling agent and the silica sol can be injected at the same time without premixing.
However, in certain leaking parts or cavities, e.g. in soil, a gelling agent in the form of e.g. a salt may already be present in the soil in -such quantity that no further gelling agent need to be added to form a sealing composition. Hence, in one preferred embodiment of the invention, solely silica sol is separately injected to a leaking part or cavity. The method can generally impart cutting off of any liquid flow of e.g. water and aqueous solutions, organic solutions etc, but the method is principally adapted to cut off flow of water and aqueous solutions.
The sealing composition may also be inserted to a leaking part or cavity by means of other methods such as jet grouting, in which at least a part of the material constituting the leaking part or cavity is removed to add the sealing composition and then reset to the same point from which it was earlier removed with the sealing composition incorporated therein. This method is preferably adapted to be used in the sealing of soil.
According to one preferred embodiment, the silica sol and the gelling agent are mixed immediately before injection. In this context, the wording "immediate"
means from about 0 to about 30 seconds, preferably from about 0 to about 15 seconds. This way of mixing the ingredients of a composition is often referred to as in-line mixing.
According to one preferred embodiment, the sealing composition may also be prepared in a batch process in advance and used suitably within 60 minutes, and preferably within 30 minutes before insertion of the composition. This way of preparing the sealing composition, however, necessitates a sufficiently stable sealing composition
The gelling agent suitably is an inorganic salt or acid, an organic salt such as sodium acetate, or acid such as acetic acid, but preferably an inorganic salt such as potassium chloride, calcium chloride, sodium chloride, magnesium chloride, magnesium sulphate, potassium iodide magnesium nitrate, sodium nitrate, potassium nitrate, calcium nitrate, and sodium silicate or mixtures thereof, preferably calcium chloride, sodium chloride or potassium chloride, and most preferably sodium chloride, sodium aluminate.
A gel time regulator such as an acidic triacetine (glycerine triacetate), diacetine, Glauber's salt (NaSO4*10H20), sulphuric acid, phosphoric acid or mixtures thereof may also be added to the sealing composition to control the gelation thereof.
The term "gel time", as used herein, means the amount of time elapsed from the moment of mixing the ingredients making up the sealing composition until the time when the sealing composition becomes too viscous to move or insert to a leaking point. The viscosity is suitably controlled in such way that a homogeneous moving front of the composition is formed moving in the direction of the point to be sealed.
Suitably, the initial viscosity of the sealing composition is from about 3 to about 100, preferably from about 4 to about 30 mPas. The gel time may easily be controlled by adjustment of the amount of gelling agent. Sometimes, instantaneous gelling without substantial dilution of the composition is necessitated to provide a gelled pressure-resisting sealing composition. A
short gel time may be optimal in cracks being relatively ground and where the risk for rapid dilution of the sealing composition exists. In some cases, it is essential especially in cracks that the gelling preferably should not start before the front of the inserted composition has fully penetrated the crack. Usually, the gel time ranges from about 1 to about 120, preferably from about 2 to about 60, more preferably from about 5 to about 40, and most preferably from about 5 to about 20 minutes in rock sealing. In soil sealing, the gel time usually ranges from about 5 minutes to about 24 hours, preferably from about 10 minutes to about 6 hours, and most preferably from about 15 minutes to about 3 hours.
The ingredients may be mixed at ambient temperature. The gelling agent is suitably added to the silica sol in an aqueous solution in a concentration from about 1 to about 30 wt%, preferably from about 2 to about 15 wt%. The silica sol, to which the gelling agent suitably is added, suitably has a silica content of from about 1 to about 70, preferably from about 20 to about 60, and most preferably from about 35 to about 50 wt%. A high silica content in the silica sol may in many instances be favourable due to reduced transportation costs of silica sol.
The silica content in the sealing composition suitably is from about I to about 60, preferably from about 15 to about 50, and most preferably from about 30 to about 45 wt%. A high silica content minimises shrinkage and maximises long term strength. The weight ratio of silica to gelling agent depends on the application and may vary depending on the application. Suitably, the weight ratio of silica particles: gelling agent is from about 400:1 to about 10:1, preferably from about 200:1 to about 20:1.
The gelling agent content in the sealing composition may vary depending on the type of gelling agent used. However, the gelling agent content suitably is from about 0.1 5'to about 10, preferably from about 0.2 to about 5 wt% of the composition. If sodium chloride is used as gelling agent, the content suitably is from about 0.2 to about 5, preferably from about 1 to about 3, and most preferably from about 1.5 to about 2 wt% of the composition. If calcium chloride is used as gelling agent, the content suitably is from about 0.1 to about 2, preferably from about 0.2 to about 1, and most preferably from about 0.25 to about 0.5 wt% of the composition.
According to a preferred embodiment, the sealing composition is inserted by injecting the silica sol separately to a leaking part or cavity whereby the sealing composition is formed in situ, e.g. in a crack of a rock or a cavity in the soil. The gelling agent may thus also be separately injected to the leaking part or cavity. This may be performed e.g. by injecting the sealing ingredients simultaneously, e.g. by placing injection nozzles for the silica sol and the gelling agent in parallel such that the gelling agent and the silica sol can be injected at the same time without premixing.
However, in certain leaking parts or cavities, e.g. in soil, a gelling agent in the form of e.g. a salt may already be present in the soil in -such quantity that no further gelling agent need to be added to form a sealing composition. Hence, in one preferred embodiment of the invention, solely silica sol is separately injected to a leaking part or cavity. The method can generally impart cutting off of any liquid flow of e.g. water and aqueous solutions, organic solutions etc, but the method is principally adapted to cut off flow of water and aqueous solutions.
The sealing composition may also be inserted to a leaking part or cavity by means of other methods such as jet grouting, in which at least a part of the material constituting the leaking part or cavity is removed to add the sealing composition and then reset to the same point from which it was earlier removed with the sealing composition incorporated therein. This method is preferably adapted to be used in the sealing of soil.
According to one preferred embodiment, the silica sol and the gelling agent are mixed immediately before injection. In this context, the wording "immediate"
means from about 0 to about 30 seconds, preferably from about 0 to about 15 seconds. This way of mixing the ingredients of a composition is often referred to as in-line mixing.
According to one preferred embodiment, the sealing composition may also be prepared in a batch process in advance and used suitably within 60 minutes, and preferably within 30 minutes before insertion of the composition. This way of preparing the sealing composition, however, necessitates a sufficiently stable sealing composition
6 that can be stored without substantial gelling until the moment of insertion.
The injection time of the sealing composition is suitably from about 1 minute to about 1 hour, preferably from about 5 minutes to about 30 minutes. The injection /penetration depth varies of course with the leak to be sealed. However, the method of the present invention is particularly beneficial for depths from about 0.5 to about 50 metres, preferably from about 5 to about 30 metres. The injection pressure suitably is from about I to about 50 bar, preferably from about 2 to about 25 bar.
The sealing composition is principally adapted to provide barriers in the subsurface for preventing leakage of water. The sealing of rock involves insertion of the sealing composition into e.g. a cavity such as a microcrack, especially to control groundwater leakage, e.g. in tunnels. By the term "microcrack" is usually meant a cavity having a diameter lower than 20 m. As the diameter of the silica particles in the silica sol is from about 10 to about 100 nm, sealing compositions containing such silica particles are of course suitable for injection into microcracks.
The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the gist and scope of the present invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the claims. The following examples will further illustrate how the described invention may be performed without limiting the scope of it.
Example 1 Sealing compositions were prepared from a salt solution of 1.7 M sodium chloride which was added under agitation to 200 g of different silica sol products as defined in the tables below. The amount of salt solution added was 40 g solution in all compositions. The compositions were aged up to 672 hours to evaluate the long term shear strength. In table 1, one set of the compositions was exposed to an increased temperature of 55 C and another set was exposed to a pH of 12 to accelerate the ageing of the sealing composition. The calculation of the particle diameter of the silica particles was made by Sear's method for calculating the specific surface area. The shear strength test was performed with the fall cone test according to the Swedish Standard 25.
Also the compressive strength was determined for the sealing compositions.
This was made by compression tests in which a load-frame, a pressure-head with the same diameter as the sample, a load cell with a plane surface where the sample is piaced between the load-cell and the pressure-head, a displacement transducer, a battery powered data-logger, a signal processing software were used. The load frame
The injection time of the sealing composition is suitably from about 1 minute to about 1 hour, preferably from about 5 minutes to about 30 minutes. The injection /penetration depth varies of course with the leak to be sealed. However, the method of the present invention is particularly beneficial for depths from about 0.5 to about 50 metres, preferably from about 5 to about 30 metres. The injection pressure suitably is from about I to about 50 bar, preferably from about 2 to about 25 bar.
The sealing composition is principally adapted to provide barriers in the subsurface for preventing leakage of water. The sealing of rock involves insertion of the sealing composition into e.g. a cavity such as a microcrack, especially to control groundwater leakage, e.g. in tunnels. By the term "microcrack" is usually meant a cavity having a diameter lower than 20 m. As the diameter of the silica particles in the silica sol is from about 10 to about 100 nm, sealing compositions containing such silica particles are of course suitable for injection into microcracks.
The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the gist and scope of the present invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the claims. The following examples will further illustrate how the described invention may be performed without limiting the scope of it.
Example 1 Sealing compositions were prepared from a salt solution of 1.7 M sodium chloride which was added under agitation to 200 g of different silica sol products as defined in the tables below. The amount of salt solution added was 40 g solution in all compositions. The compositions were aged up to 672 hours to evaluate the long term shear strength. In table 1, one set of the compositions was exposed to an increased temperature of 55 C and another set was exposed to a pH of 12 to accelerate the ageing of the sealing composition. The calculation of the particle diameter of the silica particles was made by Sear's method for calculating the specific surface area. The shear strength test was performed with the fall cone test according to the Swedish Standard 25.
Also the compressive strength was determined for the sealing compositions.
This was made by compression tests in which a load-frame, a pressure-head with the same diameter as the sample, a load cell with a plane surface where the sample is piaced between the load-cell and the pressure-head, a displacement transducer, a battery powered data-logger, a signal processing software were used. The load frame
7 forces the pressure-head to move in vertical direction. The frame is of same type as used in machine shops for controlled vertical drilling. The load is controlled by weights, which loads the load-head without any transmission (dead weight). The pressure-head consists of a rigid steel cylinder with 50 mm diameter. The load-cell has a capacity for 300 kg. The load-cell forms a plane surface. The sample is situated between the load-cell and the pressure-head. The accuracy for the load-cell is within 0.1 kg. The displacement transducer has a stroke capacity of 5 mm. The error of the actual transducer was tested by the factory to max 0,4%. The data-logger used for the tests is developed to monitor vibrations and deformations during field conditions. The logger monitors continuously during the test. The compression tests were performed only for samples cured during 28 days. The mould-cylinders size was 50 mm diameter and 25 mm height. The mould cylinders were positioned in a pot with a plane bottom. The sealing composition was then poured up to the upper end of the cylinders. All samples were cured in 20 C
water bath at pH 10. Only the cross sections where exposed to water. Before testing, the samples were separated from the mould-cylinders.
Table 1 Compositions Particle S- Surface area Shear strength Shear strength made with the diameter value on product (kPa), 55 C, (kPa), 20 C, pH
following sols: (nm) base (m2/g) pH 10, 672 h 12, 672h Soi1 17 77 68 326 -So12 12 76 88 640 475 Sol 3 11 70 100 218 So14 7 70 108 250 70 So15 5 45 75 48 39 In table 1, it can be seen that the sealing compositions made from silica sols having an S-value according to the invention results in a higher gel strength after 672 hours than the composition prepared from the comparative silica sols 3-5, both at ambient temperature and at a pH of 12 (which accelerates the ageing of the products) and at a pH of 10 and a temperature of 55 C (which also results in a faster ageing process).
water bath at pH 10. Only the cross sections where exposed to water. Before testing, the samples were separated from the mould-cylinders.
Table 1 Compositions Particle S- Surface area Shear strength Shear strength made with the diameter value on product (kPa), 55 C, (kPa), 20 C, pH
following sols: (nm) base (m2/g) pH 10, 672 h 12, 672h Soi1 17 77 68 326 -So12 12 76 88 640 475 Sol 3 11 70 100 218 So14 7 70 108 250 70 So15 5 45 75 48 39 In table 1, it can be seen that the sealing compositions made from silica sols having an S-value according to the invention results in a higher gel strength after 672 hours than the composition prepared from the comparative silica sols 3-5, both at ambient temperature and at a pH of 12 (which accelerates the ageing of the products) and at a pH of 10 and a temperature of 55 C (which also results in a faster ageing process).
8 PCT/SE02/01723 Table 2 Compositions Particle S-value Surface area on Compressive strength made from the diameter product base (m2/g) (kPa)/max load following sols: (nm) So16 35 90 40 48 Sol1 17 77 68 50 So12 12 76 88 45 So13 11 70 100 11 So15 5 45 75 11 In table 2, it can be seen that the sealing compositions prepared from the silica sols with an S-value in accordance with the present invention impart higher compressive strength than the sealing compositions made from the comparative silica sols 3 and 5.
Claims (14)
1. Use of a sealing composition for sealing rock or soil, wherein said sealing composition is obtained by mixing a silica sol having an S-value higher than about 72% and at least one gelling agent.
2. Method for cutting off a liquid flow in a leaking part or cavity by inserting a sealing composition, said sealing composition being obtained by mixing a silica sol having an S-value higher than about 72% and at least one gelling agent, into the leaking part or cavity.
3. Method for preparing a sealing composition by mixing a silica sol having an S-value higher than about 72% and at least one gelling agent.
4. Method according to claim 3, wherein the silica sol and the gelling agent are mixed in situ in a leaking part or cavity by separately injecting the silica sol to said leaking part or cavity.
5. Sealing composition obtained by mixing a silica sol having an S-value higher than about 72% and at least one gelling agent.
6. Sealing composition according to claim 5, wherein the S-value is higher than about 75%.
7. Sealing composition according to claim 5 or 6, wherein the silica sol is an aluminium modified silica sol.
8. Sealing composition according to any one of claims 5 to 7, wherein the composition has a silica content from about 35 to about 50 wt%.
9. Sealing composition according to any one of claims 5 to 8, wherein the gelling agent is selected from potassium chloride, sodium chloride, calcium chloride, magnesium chloride, magnesium nitrate, magnesium sulfate or mixtures thereof.
10. Sealing composition according to any one of claims 5 to 9, wherein the composition has a relative standard deviation of the particle size distribution lower than about 15% by numbers.
11. Sealing composition according to any one of claims 5 to 10, wherein the composition has a gelling agent content from about 0.2 to about 5 wt%.
12. Sealing composition according to any one of claims 5 to 11, wherein the silica sol comprises silica particles having a specific surface area from about 40 to about 230 m2/g.
13. Sealing composition according to any one of claims 5 to 12, wherein the composition has a weight ratio of silica particles to gelling agent from about 400:1 to about 10:1.
14. Sealing composition according to any one of claims 5 to 13, wherein the composition contains silica particles having a size within the range of from about 12 to about 50 nm.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| EP01850174.2 | 2001-10-18 | ||
| EP01850174 | 2001-10-18 | ||
| PCT/SE2002/001723 WO2003033618A1 (en) | 2001-10-18 | 2002-09-23 | Sealing composition and its use |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2463638A1 CA2463638A1 (en) | 2003-04-24 |
| CA2463638C true CA2463638C (en) | 2009-02-03 |
Family
ID=8184891
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002463638A Expired - Fee Related CA2463638C (en) | 2001-10-18 | 2002-09-23 | Sealing composition and its use |
Country Status (14)
| Country | Link |
|---|---|
| EP (1) | EP1436357A1 (en) |
| JP (1) | JP4243337B2 (en) |
| KR (1) | KR100543613B1 (en) |
| CN (1) | CN1264950C (en) |
| AR (1) | AR036828A1 (en) |
| AU (1) | AU2002337551B2 (en) |
| BR (1) | BR0213278B1 (en) |
| CA (1) | CA2463638C (en) |
| HK (1) | HK1071394A1 (en) |
| MY (1) | MY131479A (en) |
| NO (1) | NO20042047L (en) |
| NZ (1) | NZ532133A (en) |
| WO (1) | WO2003033618A1 (en) |
| ZA (1) | ZA200402800B (en) |
Families Citing this family (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4908184B2 (en) * | 2006-12-25 | 2012-04-04 | 日本化学工業株式会社 | Ground injection grout material and ground injection method |
| JP2012077307A (en) * | 2011-11-18 | 2012-04-19 | Nippon Chem Ind Co Ltd | Grouting material for grouting, and grouting method |
| CA2835677C (en) | 2012-12-19 | 2017-01-17 | E. I. Du Pont De Nemours And Company | Improved bitumen extraction process |
| EP2976310B1 (en) | 2013-03-22 | 2018-07-18 | The Chemours Company FC, LLC | Treatment of tailing streams |
| US10053613B1 (en) * | 2017-05-02 | 2018-08-21 | Saudi Arabian Oil Company | Plugging and sealing subterranean formations |
| US10407609B2 (en) * | 2017-05-02 | 2019-09-10 | Saudi Arabian Oil Company | Chemical plugs for preventing wellbore treatment fluid losses |
| KR102106475B1 (en) * | 2019-06-05 | 2020-05-04 | 박승주 | Sealant composition for cable sealing |
| EP4025666A1 (en) | 2019-09-05 | 2022-07-13 | Saudi Arabian Oil Company | Propping open hydraulic fractures |
| US11802232B2 (en) | 2021-03-10 | 2023-10-31 | Saudi Arabian Oil Company | Polymer-nanofiller hydrogels |
| US11572761B1 (en) | 2021-12-14 | 2023-02-07 | Saudi Arabian Oil Company | Rigless method for selective zonal isolation in subterranean formations using colloidal silica |
| US11708521B2 (en) | 2021-12-14 | 2023-07-25 | Saudi Arabian Oil Company | Rigless method for selective zonal isolation in subterranean formations using polymer gels |
Family Cites Families (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2630410A (en) | 1949-04-19 | 1953-03-03 | Union Carbide & Carbon Corp | Nongelling aqueous silica sols stabilized with boron compounds |
| GB1294131A (en) * | 1969-01-01 | 1972-10-25 | Borden Chemical Company Uk Ltd | Improvements in or relating to the grouting of soils |
| US3626699A (en) * | 1970-01-05 | 1971-12-14 | Borden Inc | Grouting of soils |
| LU84196A1 (en) * | 1982-06-11 | 1984-03-07 | Soletanche | AGENT FOR WATERPROOFING AND / OR CONSOLIDATION OF SOILS AND / OR CONSTRUCTION MATERIALS AND METHOD FOR ITS IMPLEMENTATION |
| JPS5993788A (en) * | 1982-11-20 | 1984-05-30 | Kyokado Eng Co Ltd | Grauting method into ground |
| US4732213A (en) * | 1986-09-15 | 1988-03-22 | Conoco Inc. | Colloidal silica-based fluid diversion |
| JPH083091B2 (en) * | 1986-12-29 | 1996-01-17 | 日産化学工業株式会社 | Ground injection chemical |
| SE500387C2 (en) | 1989-11-09 | 1994-06-13 | Eka Nobel Ab | Silica sols, process for making silica sols and using the soles in paper making |
| EP0530600A1 (en) * | 1991-08-28 | 1993-03-10 | Sika AG, vorm. Kaspar Winkler & Co. | Consolidating agent for rocks, crumbly rock, porous natural or arteficial stones and soils, and process of consolidation using this agent |
| JP3142325B2 (en) * | 1991-09-10 | 2001-03-07 | 日本化学工業株式会社 | Ground injection agent and its injection method |
| JPH06101400A (en) * | 1992-09-16 | 1994-04-12 | Asahi Denka Kogyo Kk | Injection type water stop method |
| US5370478A (en) * | 1993-05-11 | 1994-12-06 | E. I. Du Pont De Nemours And Company | Process for isolating contaminated soil |
| US5398758A (en) * | 1993-11-02 | 1995-03-21 | Halliburton Company | Utilizing drilling fluid in well cementing operations |
| US5836390A (en) | 1995-11-07 | 1998-11-17 | The Regents Of The University Of California | Method for formation of subsurface barriers using viscous colloids |
-
2002
- 2002-09-23 AU AU2002337551A patent/AU2002337551B2/en not_active Ceased
- 2002-09-23 JP JP2003536349A patent/JP4243337B2/en not_active Expired - Fee Related
- 2002-09-23 CN CNB028204824A patent/CN1264950C/en not_active Expired - Fee Related
- 2002-09-23 BR BRPI0213278-8A patent/BR0213278B1/en not_active IP Right Cessation
- 2002-09-23 WO PCT/SE2002/001723 patent/WO2003033618A1/en active IP Right Grant
- 2002-09-23 CA CA002463638A patent/CA2463638C/en not_active Expired - Fee Related
- 2002-09-23 EP EP02773089A patent/EP1436357A1/en not_active Withdrawn
- 2002-09-23 NZ NZ532133A patent/NZ532133A/en not_active IP Right Cessation
- 2002-10-10 KR KR1020020061614A patent/KR100543613B1/en not_active IP Right Cessation
- 2002-10-14 MY MYPI20023826A patent/MY131479A/en unknown
- 2002-10-16 AR ARP020103872A patent/AR036828A1/en not_active Application Discontinuation
-
2004
- 2004-04-13 ZA ZA2004/02800A patent/ZA200402800B/en unknown
- 2004-05-18 NO NO20042047A patent/NO20042047L/en not_active Application Discontinuation
-
2005
- 2005-05-13 HK HK05104038A patent/HK1071394A1/en not_active IP Right Cessation
Also Published As
| Publication number | Publication date |
|---|---|
| HK1071394A1 (en) | 2005-07-15 |
| NO20042047L (en) | 2004-07-13 |
| CN1571826A (en) | 2005-01-26 |
| BR0213278B1 (en) | 2012-09-18 |
| ZA200402800B (en) | 2005-06-29 |
| BR0213278A (en) | 2004-10-26 |
| CN1264950C (en) | 2006-07-19 |
| CA2463638A1 (en) | 2003-04-24 |
| MY131479A (en) | 2007-08-30 |
| JP4243337B2 (en) | 2009-03-25 |
| AR036828A1 (en) | 2004-10-06 |
| KR20030032847A (en) | 2003-04-26 |
| KR100543613B1 (en) | 2006-01-20 |
| WO2003033618A1 (en) | 2003-04-24 |
| NZ532133A (en) | 2005-09-30 |
| JP2005505680A (en) | 2005-02-24 |
| EP1436357A1 (en) | 2004-07-14 |
| AU2002337551B2 (en) | 2005-07-28 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US7163358B2 (en) | Injection grouting | |
| CA2463638C (en) | Sealing composition and its use | |
| KR102105058B1 (en) | Two-component thixotropic grout composition for backfilling having superior water resistance, and process of backfilling by using the same | |
| US2131338A (en) | Consolidation of porous materials | |
| KR102454889B1 (en) | Two-pack type soil grouting composition having superior water resistance, and grouting method by using the same | |
| AU2002337551A1 (en) | Sealing composition and its use | |
| EP1539652B1 (en) | Injection grouting | |
| JPS63168485A (en) | Grout to be injected into ground | |
| US6857824B2 (en) | Sealing composition and its use | |
| JP3490626B2 (en) | Filling method of cavity and injection material used for it | |
| KR20210117598A (en) | Two-component thixotropic grout composition for backfilling having superior water resistance, and process of backfilling by using the same | |
| WO2020153974A1 (en) | Method of reducing the swelling capacity of clay-containing soil | |
| JPS6118593B2 (en) | ||
| KR102413054B1 (en) | Grouting composition containing colloidal silica with high permeability into the soil and construction method using the same | |
| KR102591539B1 (en) | Chemical grout composition with enhanced durability and its applications | |
| AU2003253530B2 (en) | Injection grouting | |
| JP3396789B2 (en) | Ground injection material | |
| TWI309674B (en) | Sealing composition and its use | |
| JP2016153499A (en) | Method for manufacturing solidifying material for grouting | |
| JP2003129042A (en) | Mud loss prevention material, method for producing the same and civil engineering execution method using the same | |
| JPH1053763A (en) | Slag-based grout | |
| WO2020236107A1 (en) | A method for preparing an injection material and the obtained injection material | |
| JP2013189539A (en) | Solidifying material for ground grouting and method for manufacturing the same | |
| JPH06330037A (en) | Grouting agent | |
| JPH06330038A (en) | Grouting liquid for ground |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| MKLA | Lapsed |
Effective date: 20200923 |