JP3871057B2 - Gap filling method for structures - Google Patents

Description

  The present invention relates to existing gaps that naturally occur on the sea, water, land, and underground structures, or gaps or structures that are simply formed in these structures, such as earth, sand, metal, wood, plastic, resin, rubber, etc. The present invention relates to a method for effectively sealing a gap in a structure such as an interfacial gap in contact with a material (hereinafter referred to as a gap between structures).

  Sea, water, land, and underground structures generate gaps due to drying shrinkage, thermal expansion, and behavior, and cause corrosion of rebar and neutralization of concrete due to intrusion of spring water, rainwater, and carbon dioxide from the gap. It becomes.

In other words, reinforcing bars with strong alkalinity of PH11 or higher form a passive film on the surface, but if moisture and oxygen enter into the gaps between structures such as concrete, the passive film is destroyed and the rebar is generated. As a result of the progress of the contract, it will cause cracks in the concrete or cause the steel bars to expand and explode due to the generated Fe (OH) ₂ (ferrous hydroxide) and Fe (OH) ₃ (ferric hydroxide). Become.

In addition, when carbon dioxide gas or acid rain in the air enters from the gap between structures such as concrete, the calcium hydroxide in the concrete is neutralized from the portion near the surface or the inside of the crack by the following reaction.
Ca (OH) ₂ + CO ₂ → CaCO ₃ + H ₂ O
Ca (OH) ₂ + H ₂ SO ₄ → CaSO ₄ + 2H ₂ O

  As a method to prevent the intrusion of spring water, rainwater, carbon dioxide gas, etc. from the gap of the structure, the vicinity of the gap entrance is removed and removed with a non-shrinkable cement or the like, or silica-based around the gap entrance. Methods such as applying, spreading, and injecting fillers are being used.

  There is also a method in which a solution containing an alkali silicate is injected into a gap between structures and reacted with free calcium or calcium hydroxide inside to form a colloidal crystal of calcium silicate, thereby filling the gap.

  Furthermore, a gel-like composition is obtained by infiltrating an alkali metal silicate solution and a solution containing an alkaline earth metal salt such as calcium into the gaps between the structures by mechanical press-fitting or by self-weight pressure and hydrostatic pressure, and then curing the solution inside. There is also a method of forming gaps to fill the gaps.

  In addition, crack repair agents for concrete structures in which alcohol is added to organic acid calcium salt aqueous solutions such as acetic acid and formic acid to accelerate drying are known, but this is only repair of cracks in concrete structures. (Patent No. 3437920).

On the other hand, resin systems using epoxy resin, polyurethane resin, acrylic resin, etc. as existing fillers in the gaps between structures and cement systems using ultrafine cement, polymer cement, siliceous colloidal gel, etc., alkali silicate It can be broadly classified into those using a composition containing a salt, and the resin system is divided into a reaction type and a solvent type.
Japanese Patent No. 2937309 and Japanese Patent No. 3437920

  Of these, the reactive type is designed to block cracks, etc. while reacting polyurethane resin filler and water in the gap, preventing intrusion of spring water and rainwater, but it can be used in winter. There are drawbacks such as lack of elasticity.

  The solvent type is a type that fills the gap with urethane, polyurethane, epoxy resin, acrylic resin, etc. dissolved in a solvent, and cures these resins from the surface that comes into contact with the outside air as the solvent evaporates to close the gap. However, there is a drawback that it is difficult to cure in a deep gap.

  In addition, solvent-type urethane resin and polyurethane resin can be injected into the location where spring water and rainwater are leaking due to external pressure from the gap, but epoxy resin and acrylic resin are applied when spring water and rainwater are flowing out. There is a disadvantage that it can not.

  On the other hand, the method using non-shrinkable cement and silica-based filler as a water-stopping agent is to bring about the water-stopping effect by bringing it into contact with the active ingredients contained in spring water and rainwater entering from the gap. The liquid medicine is diluted with water and lacks immediate effect, and even if these water-stopping agents are injected or applied to the gap or the like, there are many aggregates and it is difficult to react with the active ingredient.

  In addition, regarding a method of filling a gap by forming a colloidal crystal of calcium silicate by reacting with free calcium or calcium hydroxide inside a structure such as concrete, the relationship between alkali silicate and free calcium or calcium hydroxide The reaction speed is slow, and it cannot be used where spring water or rainwater leaks from the gap due to external pressure, and it is also difficult to fill the gap in rainy weather as well.

  On the other hand, for a method of filling a gap by injecting an alkali metal silicate solution and a solution containing an alkaline earth metal salt such as calcium into the gap between the structures to form a gel composition, fill the gap. In the next 1 to 2 days, the gel-like composition undergoes a dehydration reaction, and the dehydrated liquid flows out from the vicinity of the gap, causing a drawback.

  In view of the above circumstances, the present invention provides a first solution composed of one or two or more alkali metal silicate aqueous solutions and an alkaline earth metal salt or water in an existing gap of a structure or a gap formed simply. The present invention proposes a gap filling method for a structure in which after filling and filling a second solution containing an oxide, the gap portion of the structure or the vicinity thereof is forcibly heated to seal the gap.

  The gap sealing mechanism according to the present invention is considered as follows. That is, when a first solution composed of an aqueous alkali metal silicate solution and a second solution containing an alkaline earth metal salt or hydroxide are injected into an existing gap of the structure or a gap formed easily, the gap is introduced into the gap. A dehydrated liquid containing an alkali metal silicate is generated from the formed gel-like composition and diffuses into the gap details. During this period, the alkali metal silicate in the injection solution or dehydrated liquid is forced by external heating. It is conceivable that the acid salt reacts with free calcium or calcium hydroxide in the structure to promote the formation of a glassy calcium silicate colloidal crystal to close the gap.

  Therefore, in the present invention, the gap between the structures is completely sealed off by the vitreous film or the solid matter containing the vitreous, so that the dehydration liquid or the like can be prevented from oozing out. Intrusion of gas or oxygen can be prevented, and furthermore, an elastic gel-like composition is formed at the center of the structure, and the surroundings are covered with glass or coated, so that the structure is improved. Quality can be achieved.

  In the present invention, the first solution comprising an alkali metal silicate solution and the second solution containing an alkaline earth metal salt or hydroxide may be sequentially injected into the gap between the structures. A suspension obtained by stirring and mixing the second solution may be injected.

  Alternatively, each inlet may be provided in the longitudinal direction of the gap, and the first solution and the second solution may be simultaneously pressed into the gap from each inlet and forcibly mixed and stirred inside the gap.

  In this case, it is preferable to add one or more of polyhydric alcohol and saccharide to the suspension. This is because polyhydric alcohol and saccharides are uniformly dispersed in small crystal particles in the suspension, and the suspension is uniformly dispersed and filled in the fine gaps. This is because a gel-like composition having elasticity and adhesiveness is formed and there is a water-stopping effect that is not returned by the water pressure inside the gap.

  Furthermore, the gel-like composition produces a dehydrated liquid containing alkali metal silicate by dehydration over time, but polyhydric alcohol and saccharide dissolve calcium in concrete to form alkali metal silicate. Since it reacts to form calcium silicate, the dehydration reaction of the gel-like composition can be suppressed.

  Examples of the alkali metal silicate used in the first solution in the present invention include alkali silicates such as lithium, sodium and potassium.

  In addition, as the alkaline earth metal salt used in the second solution in the present invention, an alkaline earth metal salt such as magnesium nitrite and calcium nitrite, which is a salt with an inorganic acid such as nitrous acid, an organic such as acetic acid, etc. Magnesium acetate and calcium acetate, which are salts with acids, and salts of other organic acids and alkaline earth metals, such as magnesium and calcium salts such as oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid and citric acid Examples of the hydroxide include magnesium hydroxide and calcium hydroxide.

  Further, in the present invention, the polyhydric alcohol added to the suspension can include dihydric alcohols such as glycols and trihydric alcohols such as glycerin. The glycols include propylene glycol and di-propylene. Examples of the saccharide include glucose, sucrose, and sucrose.

  The preferred blending ratio of the suspension used in the present invention is 10% to 40% by weight of alkali metal silicate with respect to 100% by weight of the first solution and the second solution, and alkaline earth metal. And 0.1 to 20% by weight of a salt or hydroxide of 0.1% by weight to 20% by weight of one or more of polyhydric alcohols and saccharides.

  In the present invention, as a method for filling the gap with the solution or suspension, for example, an existing gap in a structure or a simple method can be created by using a plastic low pressure injector, a high pressure injector, a manual grease pump, a foot injector, or the like. The filled solution or suspension is pressed from the outside to the inside by these injectors.

  The solution or suspension may be filled in the gap by a method such as high-pressure injection, hydrostatic pressure, or coating in addition to the above injector.

  In addition, as a means for forcibly heating the gap portion in which the solution or suspension is injected or in the vicinity thereof, a gas burner, a jet burner, a portable burner, a blower having a high temperature, steam such as high-temperature water or steam, a projector, a halogen A lamp etc. can be mentioned.

  The gap or the vicinity where the solution or suspension is injected is heated at a high temperature. If the heating is concentrated in one place, there is a risk of causing cracks in the structure. Heat at 100 degrees or more for 30 seconds to 2 minutes so as not to concentrate.

  When a large amount of liquid containing a filled solution or suspension, spring water, or rainwater leaks out, the leaked solution can be controlled by heating several times with a gas burner or the like.

  In the present invention, a first solution composed of one or two or more alkali metal silicate aqueous solutions and a second solution or a first solution containing an alkaline earth metal salt or hydroxide are stirred and mixed. After injecting the resulting suspension into the gap between the structures, the gap is forcibly heated with a gas burner or the like to completely close the gap with a glassy coating or a solid material containing glass. Therefore, it is possible to prevent the dehydrating liquid from oozing out, to prevent the intrusion of spring water, rainwater, carbon dioxide or oxygen from the gap, and the center of the structure is elastic. The gel-like composition is formed, and the periphery thereof is covered with glass or coated, so that the structure can be modified.

  A first solution comprising one or more alkali metal silicate aqueous solutions, and a second solution comprising an alkaline earth metal salt or hydroxide and an aqueous solution containing one or more of polyhydric alcohols and saccharides. A suspension prepared by stirring and mixing the solution is poured into a gap between structures such as concrete to form a gel-like composition in the gap, and then the gap portion or its periphery is forced by a gas burner or the like. By heating, the gap is sealed with a glassy coating or a solid material containing glassy material and an elastic gel composition.

Examples 1-14
(1) Preparation of Composition Suspension 30% to 50% by weight of sodium silicate (alkali metal silicate aqueous solution) is used as the first solution, and calcium nitrite and propylene glycol (glycol in water) separately from this ) Gum syrup (sucrose aqueous solution) was added to prepare a second solution (Examples 1 to 14 whose component ratios are shown in Table 1 below), and the first solution and the second solution were stirred at high speed to produce crystals. A suspension of the composition in which the particles were uniformly dispersed was obtained.

(2) Properties of the composition The suspension of the composition obtained here is then cured to a gel state, and further dehydrated to undergo solid-liquid separation (separation), or uniform without solid-liquid separation. Is maintained (distributed state).

  Therefore, in this example, the suspension of the composition obtained as described above is collected in a container and allowed to stand at room temperature, the size of the crystal particles, the curing time, the gel state, and the gel-like composition. The elasticity, adhesiveness, the presence or absence of dehydration reaction of the gel-like composition (whether it is separated or maintained in a dispersed state), etc. were observed. Table 3 below shows the results of microscopic measurement of the size of the crystal particles with a magnification of 6000 times (Nitescope manufactured by Itex).

  From the above data, a filler that can be filled from a fine gap to a large gap was selected, filled in the gap, and the subsequent dehydration reaction was observed. The results are shown in Table 4 below.

  According to this, in Examples 1 to 14, it was possible to obtain a temporary water stop effect by filling the gaps corresponding thereto, but the dehydrating liquid flowed into the gaps in about 1 to 2 days after filling the gaps. Then bleeding occurred.

  Therefore, 1 hour, 1 minute, 2 minutes, and 3 minutes after the end of injection, the injection point and dehydration reaction point were heated for 30 minutes to 1 minute at 100 degrees or more, and the progress after 1 week was observed. Shown in Table 4 above.

  According to this, even when the water was not stopped by one heating, the water could be stopped by repeating the heating several times.

  Even when the gel-like composition was separated into solid and liquid, the outflow of spring water and rainwater from the voids could be prevented by heating.

Examples 15-21
(1) Preparation of composition suspension Since a sample having a high density and excellent adhesion and uniformity was obtained in Example 13, the first solution having a blending ratio shown in Table 5 below in the vicinity of this blending ratio. And the second solution were stirred at high speed to obtain a suspension of the composition in which the crystal particles were uniformly dispersed.

(2) Properties of the composition The obtained suspension of the composition is collected in a container and allowed to stand at room temperature, the size of the crystal particles, the curing time, the gel state, the elasticity of the gel-like composition, the adhesion Properties, the presence or absence of a dehydration reaction of the gel-like composition (whether it is separated or maintained in a dispersed state) and the like are observed, and the results are shown in Table 6 below.

  From the above data, a filler that can be filled from a fine gap to a large gap was selected, filled in the gap, and the subsequent dehydration reaction was observed. The results are shown in Table 7 below.

  According to this, in Examples 15 to 21, it was possible to temporarily obtain a water stop effect by filling the gaps corresponding thereto, but the dehydrating liquid flowed into the gaps in about 1 to 2 days after filling the gaps. Then bleeding occurred.

  Therefore, 1 hour, 1 minute, 3 minutes, and 5 minutes after the end of injection, the injection point and dehydration reaction point were heated for 30 minutes to 1 minute at 100 degrees or more, and the progress after 1 week was observed. Shown in Table 7 above.

  According to this, all water was stopped by one heating, and no bleeding was observed even after one week.

  As Example 22, a first solution and a second solution having the same composition as in Examples 1 to 14 were prepared except that glycerin was used instead of the second solution of propylene glycol (glycols) gum syrup (sucrose aqueous solution). From this, a suspension was obtained, and an experiment similar to the above was conducted using this suspension, but no bleeding was observed.

  By covering the gaps between the sea, water, land, and underground structures completely with a glassy coating, it prevents the dehydrating liquid from seeping out, preventing the intrusion of spring water, rainwater, carbon dioxide or oxygen from the gap. Furthermore, the structure can be improved.

Claims (4)

A first solution comprising an alkali metal silicate aqueous solution of one or more kinds and an alkaline earth metal salt in an existing gap of the structure or a gap formed easily or an interfacial gap where the structure is in contact with a different material. Alternatively, after injecting a mixed solution of a second solution containing a hydroxide, or by filling the first solution and the second solution simultaneously or sequentially, the area around the gap of the structure is forcibly heated to fill the gap. A structure gap filling method characterized by sealing. The method according to claim 1, wherein a suspension prepared by mixing and stirring the first solution and the second solution is poured into the gap. The method according to claim 2, wherein one or more of polyhydric alcohol and saccharide is added to the suspension.
The first solution and the second solution are simultaneously injected from two or more injection holes formed in the gap between the structures using a high-pressure and low-pressure injection device, and are forcibly mixed and filled in the gap. Construction method.