CA1269569A - Process for subsurface reconstruction of buildings reinforced with constructional steel - Google Patents
Process for subsurface reconstruction of buildings reinforced with constructional steelInfo
- Publication number
- CA1269569A CA1269569A CA000547083A CA547083A CA1269569A CA 1269569 A CA1269569 A CA 1269569A CA 000547083 A CA000547083 A CA 000547083A CA 547083 A CA547083 A CA 547083A CA 1269569 A CA1269569 A CA 1269569A
- Authority
- CA
- Canada
- Prior art keywords
- cement
- weight
- mortar
- concrete
- solution
- 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 - Lifetime
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
- C04B41/00—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone
- C04B41/009—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone characterised by the material treated
-
- 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
-
- 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
- C04B41/00—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone
- C04B41/45—Coating or impregnating, e.g. injection in masonry, partial coating of green or fired ceramics, organic coating compositions for adhering together two concrete elements
- C04B41/50—Coating or impregnating, e.g. injection in masonry, partial coating of green or fired ceramics, organic coating compositions for adhering together two concrete elements with inorganic materials
- C04B41/5076—Coating or impregnating, e.g. injection in masonry, partial coating of green or fired ceramics, organic coating compositions for adhering together two concrete elements with inorganic materials with masses bonded by inorganic cements
- C04B41/5089—Silica sols, alkyl, ammonium or alkali metal silicate cements
-
- E—FIXED CONSTRUCTIONS
- E04—BUILDING
- E04C—STRUCTURAL ELEMENTS; BUILDING MATERIALS
- E04C5/00—Reinforcing elements, e.g. for concrete; Auxiliary elements therefor
- E04C5/01—Reinforcing elements of metal, e.g. with non-structural coatings
- E04C5/015—Anti-corrosion coatings or treating compositions, e.g. containing waterglass or based on another metal
-
- 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
- C04B2111/72—Repairing or restoring existing buildings or building materials
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Ceramic Engineering (AREA)
- Structural Engineering (AREA)
- Materials Engineering (AREA)
- Organic Chemistry (AREA)
- Architecture (AREA)
- Inorganic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Civil Engineering (AREA)
- Working Measures On Existing Buildindgs (AREA)
- Aftertreatments Of Artificial And Natural Stones (AREA)
- Vertical, Hearth, Or Arc Furnaces (AREA)
- Furnace Charging Or Discharging (AREA)
- Curing Cements, Concrete, And Artificial Stone (AREA)
Abstract
ABSTRACT
For the subsurface reconstruction of buildings reinforced with constructional steel that the damaged concrete is drilled into until behind the corroded reinforcement, the solution of a modified alkali silicate having a Me2O: SiO2 ratio of 1:2 to 1:3 being injected into the drilling under pressure and thereafter a cement-water sludge with alkali silicate solution or a mortar mixture being injected under pressure containing 2 to 6% weight relative to the amount of cement of a finely composed amorphous silicic acid with at least 90% by weight SiO2 or finely composed, precipitated, active silicates of magnesium, calcium, barium or aluminum with a BET surface of 50 to 200 m2/g and a d50% value below 20 µm.
For the subsurface reconstruction of buildings reinforced with constructional steel that the damaged concrete is drilled into until behind the corroded reinforcement, the solution of a modified alkali silicate having a Me2O: SiO2 ratio of 1:2 to 1:3 being injected into the drilling under pressure and thereafter a cement-water sludge with alkali silicate solution or a mortar mixture being injected under pressure containing 2 to 6% weight relative to the amount of cement of a finely composed amorphous silicic acid with at least 90% by weight SiO2 or finely composed, precipitated, active silicates of magnesium, calcium, barium or aluminum with a BET surface of 50 to 200 m2/g and a d50% value below 20 µm.
Description
356~
Translation October 15, 1986 ~o. 25 Process_for sub_urface reconstruction of huildinqs rein-forced with_constructional steel S p e c i f _i c a t i o n - In structures made of reinforced concrete the concrete has two functions to fulfill. It has to absorb compres-slve strains and it has to protect the steel against corrosion. The reinforced steel serves the function of absorbing the shear anc1 tensile stress.
The protective effect of the hardened cement paste for the iron and its duration are dependent on several factors. On the one hand there are the climatic and environmental conditions and on the other hand there is the quality of the concrete which is primarily determined by the amounts of ceme1lt, the grain of the concrete aggregate, the water cement -~actor and the concrete compression.
The protective effect of the concrete for the iron is dependent on the high alkalinity of the Ca(OH)2 produced during hydrolysis - pH around 13. The carbonic acid formed by the carbon dioxide in the alr toget11er with water reacts with the calcium iOllS of~the calcium silicate hydrate or calcium aluminate hydrate phases of the hardened cement paste forming calcium carbonate.
The concrete carbonates, as this process is generally called, at a concrete dampness, ~hich arises at :
,. - , :,, -; ' ...
, .: ~,: , ; :
, ::: ': .. :. ,. :
:
- Z~ 6~356~3 a relative humidity of under around 60~o If the concrete pores are practically completely filled with water, the carbonation comes to a halt. ~ow quickly and how deep the carbonation penetrates the concrete depends on the dampness of the concrete and its structure. ~n the case of complete carbonation the pH value of the concrete drops to around 8~ The corrosion of the iron still does not need to set in if as in the inner spaces the concrete is dry. Concrete dampnesses ~hich come about at relative humidities of between 80 and 100~, lead to the formation of rust on the reinforced iron, as soon as the p~ value of the surroundinq institial fluid drops below 9.5. The eorrosion is increased substantially by salts (thawing salts) which penetrate together with the ~ater. In particular the chloride ions lead to the feared holes being eaten into the iron, ~hich then reduces the supporting capacity of the structure. sut also the overall surfaca corrosion of the iron, which only leads to an insignificant loss in strenc3th of the building structure in the beginnin~, can already cause lar~e follow-up damage. The ta~e up of oxygen and hydration water increases the weight of the corrosion product, FezO3 x H2O, referring to the aMount of corroded iron to the amount of absorbed hydration water. Depending upon the amount of the ahsorbed hydration water and the embedded salts the corrosion products of the steel can take on four to eight times the original volume. As a result of the increase in volume first of all the surface layers split away. Later cracks form throughout the entire buildinc3 ~n entire system of steps is necessary to repair reinforced concrete which has been damaged in this manner. This system must be adapted to the charaeteristics of the corroded steel and the carbonated concrete. A lasting reconstruction of the building can only be attained, if one succeeds in 1. eliminating any further corrosion of the steel,
Translation October 15, 1986 ~o. 25 Process_for sub_urface reconstruction of huildinqs rein-forced with_constructional steel S p e c i f _i c a t i o n - In structures made of reinforced concrete the concrete has two functions to fulfill. It has to absorb compres-slve strains and it has to protect the steel against corrosion. The reinforced steel serves the function of absorbing the shear anc1 tensile stress.
The protective effect of the hardened cement paste for the iron and its duration are dependent on several factors. On the one hand there are the climatic and environmental conditions and on the other hand there is the quality of the concrete which is primarily determined by the amounts of ceme1lt, the grain of the concrete aggregate, the water cement -~actor and the concrete compression.
The protective effect of the concrete for the iron is dependent on the high alkalinity of the Ca(OH)2 produced during hydrolysis - pH around 13. The carbonic acid formed by the carbon dioxide in the alr toget11er with water reacts with the calcium iOllS of~the calcium silicate hydrate or calcium aluminate hydrate phases of the hardened cement paste forming calcium carbonate.
The concrete carbonates, as this process is generally called, at a concrete dampness, ~hich arises at :
,. - , :,, -; ' ...
, .: ~,: , ; :
, ::: ': .. :. ,. :
:
- Z~ 6~356~3 a relative humidity of under around 60~o If the concrete pores are practically completely filled with water, the carbonation comes to a halt. ~ow quickly and how deep the carbonation penetrates the concrete depends on the dampness of the concrete and its structure. ~n the case of complete carbonation the pH value of the concrete drops to around 8~ The corrosion of the iron still does not need to set in if as in the inner spaces the concrete is dry. Concrete dampnesses ~hich come about at relative humidities of between 80 and 100~, lead to the formation of rust on the reinforced iron, as soon as the p~ value of the surroundinq institial fluid drops below 9.5. The eorrosion is increased substantially by salts (thawing salts) which penetrate together with the ~ater. In particular the chloride ions lead to the feared holes being eaten into the iron, ~hich then reduces the supporting capacity of the structure. sut also the overall surfaca corrosion of the iron, which only leads to an insignificant loss in strenc3th of the building structure in the beginnin~, can already cause lar~e follow-up damage. The ta~e up of oxygen and hydration water increases the weight of the corrosion product, FezO3 x H2O, referring to the aMount of corroded iron to the amount of absorbed hydration water. Depending upon the amount of the ahsorbed hydration water and the embedded salts the corrosion products of the steel can take on four to eight times the original volume. As a result of the increase in volume first of all the surface layers split away. Later cracks form throughout the entire buildinc3 ~n entire system of steps is necessary to repair reinforced concrete which has been damaged in this manner. This system must be adapted to the charaeteristics of the corroded steel and the carbonated concrete. A lasting reconstruction of the building can only be attained, if one succeeds in 1. eliminating any further corrosion of the steel,
2. reinstatinc3 a strong bond between the steel and and the concrete, : :
' :' ~ ,:' : , ' ' ' ' ' . -
' :' ~ ,:' : , ' ' ' ' ' . -
-3- ~6~S~9 3. filling the Inissing spots with a repairing mortar which adheres tightl~ to the old concrete and the iron and then
4. in sealing the entire outer surface of the structure against the penetration of moisture.
If we disregard the secondary work necessary, we can easily divide the repair process into two phases. The first concerns puttinq an end to the corrosion of the steel and the second concerns filling the holes and cracks in the concrete surface.
The known repair processes require eight steps which in part are very complicated: A~ter the concrete steel is uncovered the steel has to be sand blasted until is has a metallic shine. ~'3 a third step a protective coating is applied to the steel wllich is then sprin]cled with sand which serves as an a~hesive bridge for the repair rnortar, before the protective coating dries. In the fourth step the cavities in the concrete surface are coated with a sand-polymer-cement-water mixture so that the filling mixture consisting of a synthetic cement mortar bonds well to the old concrete. The urther steps involve the final treatment of the concrete surface, the evening out of the concrete surface, coating the same with a primer and applying a protective coating which prevents the carbonation of the upper concrete layers.
(Paint & Resin Oct. 1984, P. 33-37) The complete sand blast removal of rust is only possible all overr if the constructional steel can be uncovered enough, in particular the the space between the reverse side of the steel and the concrete has to be big enough so that the spray je~ can be introduced into it to remove the rustO
The DE-OS 35 13 566 describe~ a process for inhibitinc3 the corrosion of steel material, which is built into anorganic building materials, the surface of ~hicll con-sisting of reinforced concrete is i~pregnated consecut-ively with an aqueous solution of an anorganic salt .
! :~
.: '' .
356~3 which has a corrosion inhibiting effect on the steel material and with an aqueous solution of a water-soluble silicate. Nitrites, in particular, are used as corrosion protec-tion inhibiting salts. It is determined in this reference that alXali silitcates alone do not produce an adequate corrosion protection.
The repair mortar described in the literature contains besides cement, sand and water also synthetic resin dispersions. To 1 part by volume (loose pouring) cement 0.1 to 1.0 parts by volume synthe-tic dispersion are used. With respect to the cement that is around ~ to 48 % in weight of synthetic resin dispersion. ~orking with cement mortar tempered and hardened with synthetic resin (KVZ mortar) is made more difficult by the fact that it has to be processed within 30 to 45 minutes or else setting difficulties arise. Further atmospheric condi-tions and the degree oE dampness of the concrete founda-tion hamper the repair worlc. At ternperatures below 5 to 8 C, if it rains and conditions are damp and cold and the foundation is wet working ~lith this mortar group is out of the question.
Whereas cement hardens hydraulically, i.e. requiring water to set, contrarily -the synthetic resin part of the mortar hardens after the water has evaporated. Therefore there is no need for subse~uent wetting of the repair layer, which however is detrimental to the cement compo-nents in the case o low relative hurnidities. The con-flicting chelnical and physical character of cement and synthetic resin disperion and of hardened concrete and synthetic resin makes the use of KVZ mortar problematic, in particular the higher the amount of synthetic resin is.
In wet years still another disadvantage of repairing walls with ICVZ mortar showed up. The facades became green with algae. Bui1ding components containing synthetic resins, if sufficient dampness occurs, are a good nutritive .::
-1~6~569 medium for parasites and other lower life forms.
The two-component synthetic resin mortar with a epoxy resin or polyurethane base do not need to be treated here as extraneous to this type of mortar, although they too are suitable for repairing concrete surfaces under certain conditions.
The great exper1se including the secondary work of removing the rust (further chiselling out of the concrete and the sand blastin~) and the work of producing a protective coating with the known anti-corrosive paints which completely covers the steel as well as the problems which may arise through the use of alkali sensitive finishing coats (concrete p~l = around 13), indicate the necessity for a simplification and improvement oE the l?rocesses for reconstructing building structures made of reinforced concrete.
It was not possible with the known working processes and the known means to reconstruct steel structures or brick veneered steel constructions through and through.
The object of the invention is to reconstruct buildings which are made of reinforced concrete or of steel con-structions, which have a sandstone, a natural stone, a concrete stone or bric]c stone veneer in other words buildings made of a combination steel and silicate mate-rials. An additional dalnage promoting factor along with the problems of reinforced concrete structures already described is the formation of cracks in the bonding of stone and the joint-fillir1g mortar which is caused by the varying behavior of these materials under telnpera-ture fluc-tuation~
Whereas in the case of reinforced concrete following appropriate construction mainly only the surface and the layers near the surface e~hibit cracks, for this type of structure the cracks run throucJhout the er1tire width of the wall ril~ht on throuc;h to the support construction.
:: :
. :
956~3 The rain water, which always contains oxy~en dissolved in it, can penetrate to the iron practically without any problem. The salts also have a corrosion promoting effect. They are transported dissolvecl in the rain water on their way from the outer lay through the mortar and the cracks in the stone.
According to the process of this inVerltiQn for subsur-face reconstruction of structures made of a combination of steel and silicate materials the damaged concrete or the damaged veneer is first drilled through to behind the corrodecl reinforcement or to the steel construction without damaging the steel parts in doing so. Then the solution of a modified alkali silicate having a ~le~O :
SiO~ ratio of 1:2 to 1:3 is injected. Depending on the local condition~c a pressure is recluired of between 0.1 N/mm~ to 7 ~l/mm~ and maxirllum 25 N/mrn2. Under similar pressure conditiorls a cement-water slud~Je preferably under the acldition th~reto of a small amount of the above described modified alkali silicate solution is injected until the pressure in the system remains con-stant without the material being transported. Instead of the cement slud(3e a fine sand mortar may also he used, which relative to the amount of cement contains 2 to 6 by weight of a finely composed amorphous silicic acid having at least go !o by weight of SiOz, or finely com-posed, precipitated active silicates of magnesium, cal-cium, barium or alumin-lm, which has a specific surface according to~BET of between 50 to 200 m~/g and a d50 value below 20 ~M. After the injection supports have been removed from the drilling holes, the holes are filled and closed off with a mortar mixture of type described above. Finally the outer surface oE the recon-structed builclin~ parts is saturated with the modified alkali silicate solution used in the first process step.
In the above general formula l~le~O for the alkali oxide part of l:he modified alkali silicate ~le means lithium, sodiwn or potassium, whereby the latter is preferred in - ~ , , .
956~
the mix-ture with sodiu~ percent hy volume of the alkali silicat is ~sually dilute-l with 0.5 to 2 percent by volume water if it is used in treating surfaces~ That corresponds to SiO2concentrations in the solution of around 7 to 20 percent by weicJht. The B~T method used above and in the following for determining the surface by calculating the monolayer capacity is from Brunauer, Emmet and Teller and is described inter alia in "Ullmanns En~yklopadie der technisc]1en Chemie, Band II/1", P.
758/759.
Por the grain analysis an apparatus made by the Cilas company is used. It functions according to the laser beam method. This method is described by J. Swithenhank et al~ in "Experirnental ciiagnostics in gas phase combustion systems, Progress in ~strona-ltics and Aeronautics, Vol. 53, (1~77)".
PreEerred as the ~ineLy coinposed sllicates added to the rnortar are hariuln silicate with a composition of 40%
BaO, 52~ SiO~ and 8~ anneaLing loss or a sodium aluminum silicate with a composition of 73 % SiO~, 7~ Al~O~, 7 Na O and 12~ annealing loss.
It is surprising -tl1at the combination of the steps of the invention together witl1 the means used in the invention is sufficient to reconstruct struc-tures made of reinforced concrete or steel constructions, which have a sandstone, concrete stone or brickstone ~eneer, in a simple and lasting rnanner.
The above descrihed methocl for subsurface reconstruction can also be a~plied to ~tructures without a steel construction which e~hibit too low of a strength or which are not water-ti;3llt. ~rhe compressive strength of the building com~onents treated by means of the method for subsurface reconstruction defined in the invention is increased and hetweel1 these components a water-ti~ht structure is produce(l.
~95~
The relatively low ainount of between 2 - 6 percent by weight of a finely composed amorphous silicic acid or a Na-A1-silicate improves the processing characteristics of the cement-sand-water mixture by practically unchanged setting b~havior.
There is no phase separatioll which occurs by the floa-ting to the surface of water with fine amounts of cement in other words the socalled bleeding of the mortar or of the concrete is completely eliminated. This mortar mix-ture with the same water/cement factor is also more plastic. Therefore the mortar can be injected better into narrow joints and the surface be spread more smoothly. The repair mortar used in the invention is also water-tight without ally subsequent treatrllellt, main-tains its perlneability to water vapor however.
The following example will explain the method of the invention in more detail.
Example 1 For subsurface reconstruction the drilling holes of a diameter between aro~nd 6 to 23 rnm are set so close to one another that the injection material injected into the ~rilling hole carl ~enetrate to the adjacent drilling holes.
.. :
If we disregard the secondary work necessary, we can easily divide the repair process into two phases. The first concerns puttinq an end to the corrosion of the steel and the second concerns filling the holes and cracks in the concrete surface.
The known repair processes require eight steps which in part are very complicated: A~ter the concrete steel is uncovered the steel has to be sand blasted until is has a metallic shine. ~'3 a third step a protective coating is applied to the steel wllich is then sprin]cled with sand which serves as an a~hesive bridge for the repair rnortar, before the protective coating dries. In the fourth step the cavities in the concrete surface are coated with a sand-polymer-cement-water mixture so that the filling mixture consisting of a synthetic cement mortar bonds well to the old concrete. The urther steps involve the final treatment of the concrete surface, the evening out of the concrete surface, coating the same with a primer and applying a protective coating which prevents the carbonation of the upper concrete layers.
(Paint & Resin Oct. 1984, P. 33-37) The complete sand blast removal of rust is only possible all overr if the constructional steel can be uncovered enough, in particular the the space between the reverse side of the steel and the concrete has to be big enough so that the spray je~ can be introduced into it to remove the rustO
The DE-OS 35 13 566 describe~ a process for inhibitinc3 the corrosion of steel material, which is built into anorganic building materials, the surface of ~hicll con-sisting of reinforced concrete is i~pregnated consecut-ively with an aqueous solution of an anorganic salt .
! :~
.: '' .
356~3 which has a corrosion inhibiting effect on the steel material and with an aqueous solution of a water-soluble silicate. Nitrites, in particular, are used as corrosion protec-tion inhibiting salts. It is determined in this reference that alXali silitcates alone do not produce an adequate corrosion protection.
The repair mortar described in the literature contains besides cement, sand and water also synthetic resin dispersions. To 1 part by volume (loose pouring) cement 0.1 to 1.0 parts by volume synthe-tic dispersion are used. With respect to the cement that is around ~ to 48 % in weight of synthetic resin dispersion. ~orking with cement mortar tempered and hardened with synthetic resin (KVZ mortar) is made more difficult by the fact that it has to be processed within 30 to 45 minutes or else setting difficulties arise. Further atmospheric condi-tions and the degree oE dampness of the concrete founda-tion hamper the repair worlc. At ternperatures below 5 to 8 C, if it rains and conditions are damp and cold and the foundation is wet working ~lith this mortar group is out of the question.
Whereas cement hardens hydraulically, i.e. requiring water to set, contrarily -the synthetic resin part of the mortar hardens after the water has evaporated. Therefore there is no need for subse~uent wetting of the repair layer, which however is detrimental to the cement compo-nents in the case o low relative hurnidities. The con-flicting chelnical and physical character of cement and synthetic resin disperion and of hardened concrete and synthetic resin makes the use of KVZ mortar problematic, in particular the higher the amount of synthetic resin is.
In wet years still another disadvantage of repairing walls with ICVZ mortar showed up. The facades became green with algae. Bui1ding components containing synthetic resins, if sufficient dampness occurs, are a good nutritive .::
-1~6~569 medium for parasites and other lower life forms.
The two-component synthetic resin mortar with a epoxy resin or polyurethane base do not need to be treated here as extraneous to this type of mortar, although they too are suitable for repairing concrete surfaces under certain conditions.
The great exper1se including the secondary work of removing the rust (further chiselling out of the concrete and the sand blastin~) and the work of producing a protective coating with the known anti-corrosive paints which completely covers the steel as well as the problems which may arise through the use of alkali sensitive finishing coats (concrete p~l = around 13), indicate the necessity for a simplification and improvement oE the l?rocesses for reconstructing building structures made of reinforced concrete.
It was not possible with the known working processes and the known means to reconstruct steel structures or brick veneered steel constructions through and through.
The object of the invention is to reconstruct buildings which are made of reinforced concrete or of steel con-structions, which have a sandstone, a natural stone, a concrete stone or bric]c stone veneer in other words buildings made of a combination steel and silicate mate-rials. An additional dalnage promoting factor along with the problems of reinforced concrete structures already described is the formation of cracks in the bonding of stone and the joint-fillir1g mortar which is caused by the varying behavior of these materials under telnpera-ture fluc-tuation~
Whereas in the case of reinforced concrete following appropriate construction mainly only the surface and the layers near the surface e~hibit cracks, for this type of structure the cracks run throucJhout the er1tire width of the wall ril~ht on throuc;h to the support construction.
:: :
. :
956~3 The rain water, which always contains oxy~en dissolved in it, can penetrate to the iron practically without any problem. The salts also have a corrosion promoting effect. They are transported dissolvecl in the rain water on their way from the outer lay through the mortar and the cracks in the stone.
According to the process of this inVerltiQn for subsur-face reconstruction of structures made of a combination of steel and silicate materials the damaged concrete or the damaged veneer is first drilled through to behind the corrodecl reinforcement or to the steel construction without damaging the steel parts in doing so. Then the solution of a modified alkali silicate having a ~le~O :
SiO~ ratio of 1:2 to 1:3 is injected. Depending on the local condition~c a pressure is recluired of between 0.1 N/mm~ to 7 ~l/mm~ and maxirllum 25 N/mrn2. Under similar pressure conditiorls a cement-water slud~Je preferably under the acldition th~reto of a small amount of the above described modified alkali silicate solution is injected until the pressure in the system remains con-stant without the material being transported. Instead of the cement slud(3e a fine sand mortar may also he used, which relative to the amount of cement contains 2 to 6 by weight of a finely composed amorphous silicic acid having at least go !o by weight of SiOz, or finely com-posed, precipitated active silicates of magnesium, cal-cium, barium or alumin-lm, which has a specific surface according to~BET of between 50 to 200 m~/g and a d50 value below 20 ~M. After the injection supports have been removed from the drilling holes, the holes are filled and closed off with a mortar mixture of type described above. Finally the outer surface oE the recon-structed builclin~ parts is saturated with the modified alkali silicate solution used in the first process step.
In the above general formula l~le~O for the alkali oxide part of l:he modified alkali silicate ~le means lithium, sodiwn or potassium, whereby the latter is preferred in - ~ , , .
956~
the mix-ture with sodiu~ percent hy volume of the alkali silicat is ~sually dilute-l with 0.5 to 2 percent by volume water if it is used in treating surfaces~ That corresponds to SiO2concentrations in the solution of around 7 to 20 percent by weicJht. The B~T method used above and in the following for determining the surface by calculating the monolayer capacity is from Brunauer, Emmet and Teller and is described inter alia in "Ullmanns En~yklopadie der technisc]1en Chemie, Band II/1", P.
758/759.
Por the grain analysis an apparatus made by the Cilas company is used. It functions according to the laser beam method. This method is described by J. Swithenhank et al~ in "Experirnental ciiagnostics in gas phase combustion systems, Progress in ~strona-ltics and Aeronautics, Vol. 53, (1~77)".
PreEerred as the ~ineLy coinposed sllicates added to the rnortar are hariuln silicate with a composition of 40%
BaO, 52~ SiO~ and 8~ anneaLing loss or a sodium aluminum silicate with a composition of 73 % SiO~, 7~ Al~O~, 7 Na O and 12~ annealing loss.
It is surprising -tl1at the combination of the steps of the invention together witl1 the means used in the invention is sufficient to reconstruct struc-tures made of reinforced concrete or steel constructions, which have a sandstone, concrete stone or brickstone ~eneer, in a simple and lasting rnanner.
The above descrihed methocl for subsurface reconstruction can also be a~plied to ~tructures without a steel construction which e~hibit too low of a strength or which are not water-ti;3llt. ~rhe compressive strength of the building com~onents treated by means of the method for subsurface reconstruction defined in the invention is increased and hetweel1 these components a water-ti~ht structure is produce(l.
~95~
The relatively low ainount of between 2 - 6 percent by weight of a finely composed amorphous silicic acid or a Na-A1-silicate improves the processing characteristics of the cement-sand-water mixture by practically unchanged setting b~havior.
There is no phase separatioll which occurs by the floa-ting to the surface of water with fine amounts of cement in other words the socalled bleeding of the mortar or of the concrete is completely eliminated. This mortar mix-ture with the same water/cement factor is also more plastic. Therefore the mortar can be injected better into narrow joints and the surface be spread more smoothly. The repair mortar used in the invention is also water-tight without ally subsequent treatrllellt, main-tains its perlneability to water vapor however.
The following example will explain the method of the invention in more detail.
Example 1 For subsurface reconstruction the drilling holes of a diameter between aro~nd 6 to 23 rnm are set so close to one another that the injection material injected into the ~rilling hole carl ~enetrate to the adjacent drilling holes.
.. :
5~9 The material used for the first injection consists of a modified alkali silicate solution with the follo~1ing composition:
SiO~ 19.14 ~
Na~ 7.54 %
CrO~L 0.31 CO~ 0.7 Ethanol 0.92 ~
rrhe rest at 100~ consisted of water Weight ratio SiO Na O - 2.54 : 1 Density 1.251 Viscosity 10.1 cP
Surface tensioll 54 dyn/cm prl value 11.4 The injection pressure is dependent on the quality anc1 the original state or the buildinc3 structure to be treated and ran~es from 'i to 70 bar. 'rhe injectior1 o~
this solution i5 continued until saturation of the solidium of the builc1ing is attained, this bein~
lndicated by the pressure constancy in the pump system.
The material for the second lnjection consists of a water-cernent sluc1ge under addition of 2 to 6 % by weight, relative to the amount oE the cement, of an active silicic acid or an active Na-Al-silicate and/or a modified alkali silicate solution with the above indicated co~lL~osition. The water/cement factor is variable and has to be adapted to the pore structure of the building structure. Instead of the cement sludge a ~fine sand mortar can be used, especially if large inner cracks and larger caverrls are present in the soliclium of ~the building. rrhe corllplete filliny of the hollow cavities is also inc1icated here by a constant pr~ssalre of 5 - 70 bar.
Finally the drillin~J noles are filled and closed off by hand usiny the mortar of this invention.
. . , .. ~ ,-. .
. .
: . . :
.:
~ `. ~ '' : . ,
SiO~ 19.14 ~
Na~ 7.54 %
CrO~L 0.31 CO~ 0.7 Ethanol 0.92 ~
rrhe rest at 100~ consisted of water Weight ratio SiO Na O - 2.54 : 1 Density 1.251 Viscosity 10.1 cP
Surface tensioll 54 dyn/cm prl value 11.4 The injection pressure is dependent on the quality anc1 the original state or the buildinc3 structure to be treated and ran~es from 'i to 70 bar. 'rhe injectior1 o~
this solution i5 continued until saturation of the solidium of the builc1ing is attained, this bein~
lndicated by the pressure constancy in the pump system.
The material for the second lnjection consists of a water-cernent sluc1ge under addition of 2 to 6 % by weight, relative to the amount oE the cement, of an active silicic acid or an active Na-Al-silicate and/or a modified alkali silicate solution with the above indicated co~lL~osition. The water/cement factor is variable and has to be adapted to the pore structure of the building structure. Instead of the cement sludge a ~fine sand mortar can be used, especially if large inner cracks and larger caverrls are present in the soliclium of ~the building. rrhe corllplete filliny of the hollow cavities is also inc1icated here by a constant pr~ssalre of 5 - 70 bar.
Finally the drillin~J noles are filled and closed off by hand usiny the mortar of this invention.
. . , .. ~ ,-. .
. .
: . . :
.:
~ `. ~ '' : . ,
Claims (6)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. Method for subsurface reconstruction of buildings reinforced with constructional steel characterized in that the damaged concrete is drilled into until behind the corroded reinforcement, the solution of a modified alkali silicate having a Me2O:SiO2 ratio of 1:2 to 1:3 being injected into the drilling under pressure and thereafter a cement-water sludge with alkali silicate solution or a mortar mixture being injected under pressure containing 2 to 6% by weight relative to the amount of cement of a finely composed amorphous silicic acid with at least 90%
by weight SiO2 or finely composed, precipitated, active silicates of magnesium, calcium, barium or aluminum with a BET surface of 50 to 200 m2/g and a d50% value below 20 µm.
by weight SiO2 or finely composed, precipitated, active silicates of magnesium, calcium, barium or aluminum with a BET surface of 50 to 200 m2/g and a d50% value below 20 µm.
2. A method according to claim l characterized in that the finely composed precipitated silicates exhibit a SiO content of 56 to 85%, with respect to the waterfree substance.
3. A method according to claim l characterized in that the precipitated finely composed active and amorphous silicates of aluminum contain 5 to 15% by weight Al2O3 and 1 to 10% by weight Na2O, with respect to the waterfree substances.
4. A method according to claim 2 characterized in that the precipitated finely composed active and amorphous silicates of aluminum contain 5 to 15% by weight Al2O3 and 1 to 10% by weight Na2O, with respect to the waterfree substances.
5. A method according to claim 1, 2 or 3 characterized in that the entire concrete surface of the reconstructed building components, once the setting process of the mortar is completed, is saturated with the solution of the modified alkalisilicate.
6. A method according to claim 4 characterized in that the entire concrete surface of the reconstructed building components, once the setting process of the mortar is completed, is saturated with the solution of the modified alkalisilicate.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19863635253 DE3635253A1 (en) | 1986-10-16 | 1986-10-16 | METHOD FOR DEEP RENOVATION OF CONSTRUCTION ARMY ARMED |
| DEP3635253.5 | 1986-10-16 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1269569A true CA1269569A (en) | 1990-05-29 |
Family
ID=6311859
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000547083A Expired - Lifetime CA1269569A (en) | 1986-10-16 | 1987-09-16 | Process for subsurface reconstruction of buildings reinforced with constructional steel |
Country Status (5)
| Country | Link |
|---|---|
| EP (1) | EP0264541B1 (en) |
| AT (1) | ATE57904T1 (en) |
| CA (1) | CA1269569A (en) |
| DE (2) | DE3635253A1 (en) |
| ES (1) | ES2018500B3 (en) |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE4219034A1 (en) * | 1992-06-10 | 1993-12-16 | Hans Jaklin | Improvement of the freeze-thaw resistance of concrete structures |
| DE4219680C2 (en) * | 1992-06-16 | 1999-01-14 | Johann Memmen | Process for silicification and waterproofing of masonry |
| DE4220274C2 (en) † | 1992-06-20 | 1997-08-21 | Hans Jaklin | Shatter resistant to flaking under fire conditions |
| DE4226141C2 (en) * | 1992-08-07 | 1997-09-25 | Basalt Feuerfest Gmbh | Acid-resistant putty, especially for use in industrial furnace construction |
| GB9718713D0 (en) * | 1997-09-03 | 1997-11-12 | Bagrat Uk Limited | The stabilisation of soluble sulphates in substratum materials |
| DE102005043272B4 (en) * | 2005-05-18 | 2010-12-30 | Ralf Peter Jaklin | Repair of buildings and parts of buildings |
| WO2014106590A1 (en) * | 2013-01-07 | 2014-07-10 | Sika Technology Ag | Method for restoring a cementitious system |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR1079484A (en) * | 1952-06-23 | 1954-11-30 | Process for the production of waterproof products using cement or concrete mortars | |
| DE1022373B (en) * | 1952-12-18 | 1958-01-09 | Skoevde Gasbetong Aktienbolag | Reinforcing steel with a rust protection layer |
| FR1420343A (en) * | 1965-01-13 | 1965-12-03 | Elimination, by cathodic or anodic inhibitors, of the danger of electrolytic corrosion of the steel reinforcements of reinforced or prestressed concrete, when calcium chloride or other saline accelerators are used | |
| DE2363794A1 (en) * | 1973-12-21 | 1975-07-03 | Fred Uhl | METHOD AND DEVICE FOR CONSOLIDATING MORBID AND STATIC ENDANGERED SANDSTONE |
-
1986
- 1986-10-16 DE DE19863635253 patent/DE3635253A1/en not_active Withdrawn
-
1987
- 1987-06-10 AT AT87108339T patent/ATE57904T1/en not_active IP Right Cessation
- 1987-06-10 ES ES87108339T patent/ES2018500B3/en not_active Expired - Lifetime
- 1987-06-10 EP EP87108339A patent/EP0264541B1/en not_active Expired - Lifetime
- 1987-06-10 DE DE8787108339T patent/DE3765903D1/en not_active Expired - Lifetime
- 1987-09-16 CA CA000547083A patent/CA1269569A/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| EP0264541B1 (en) | 1990-10-31 |
| DE3635253A1 (en) | 1988-04-28 |
| ES2018500B3 (en) | 1991-04-16 |
| DE3765903D1 (en) | 1990-12-06 |
| EP0264541A1 (en) | 1988-04-27 |
| ATE57904T1 (en) | 1990-11-15 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| KR102063011B1 (en) | Mortar for reparing cross section of concrete structure and construction method for reparing cross section of concrete structure using the same | |
| KR101893060B1 (en) | Mortar composition for repairing and reinforcing concrete structure, and method of repairing and reinforcing concrete structure using the same | |
| KR101814960B1 (en) | Mortar composition for repairing cross-section of concrete structure with fast hardening, durability and waterproof, and method of repairing cross-section of concrete structure using the same | |
| US4559241A (en) | Method for preventing hardened cementitious material from deteriorating | |
| KR100816891B1 (en) | Mineral micro putty and water soluble ceramic paint for improving porous structure of concrete surface and method coating concrete surface with mineral micro putty and water soluble ceramic paint | |
| JP7243982B2 (en) | Concrete repair agent | |
| US7429295B2 (en) | Aqueous chemical mixture to mitigate water associated problems in concrete pavements | |
| US5449533A (en) | Modifier for porous materials and method of modifying porous materials | |
| CA1333764C (en) | Method for preventing the corrosion of steel structures or steel reinforcements of buildings | |
| US4867791A (en) | Process for subsurface reconstruction of buildings reinforced with constructional steel | |
| KR101798953B1 (en) | Mortar composition for repairing and reinforcing concrete structure with superior property of waterproof and rust prevention, and method of repairing and reinforcing concrete structure using the same | |
| CA1269569A (en) | Process for subsurface reconstruction of buildings reinforced with constructional steel | |
| KR102108406B1 (en) | Inorganic nano-ceramic composition and method of coating concrete structure using the same | |
| KR100394307B1 (en) | Poromeric and repellent floor finishing method of concrete surface for improvement of durability or renewal | |
| KR100526418B1 (en) | Concrete surface treatment method using inorganic repairing agent for concrete | |
| US5021260A (en) | Method of preventing the deterioration of a hardened cement-based mass | |
| JP4616930B1 (en) | Protecting concrete structures | |
| KR102079900B1 (en) | Method of reinforcement and protection of concrete by recovery of concrete neutralization | |
| RU2235083C2 (en) | Material for waterproofing of porous building surface | |
| JPS62265189A (en) | Degradation preventive construction for cementitious material | |
| KR102449813B1 (en) | The Surface Hardener composition having crack repair function | |
| US5531822A (en) | Modifier for porous materials and method of modifying porous materials | |
| KR102601921B1 (en) | Elastic Putty Composition for Repairing Cracks on the Exterior Wall of Concrete Structures and Method of Repairing Concrete Structures Using the Same | |
| KR100312796B1 (en) | Ambient Temperature Curing Inorganic Binder Composition Comprising Colloid Silica Sol Catalyst, and Method of Treating Porous Structure Using the Same | |
| JP2021113140A (en) | Method for enhancing hardness of cement-based structure |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKLA | Lapsed |