Ground grouting agent and ground grouting method using same

Abstract

This ground grouting agent is composed of Agent A, which contains cement in water or an aqueous solution, and Agent B, which is obtained by blending sodium silicate powder, in which the molar ratio of SiO2 to Na2O (SiO2 / Na2O) is 0.5 to 1.5 and the number of waters of hydration is 9 or less, in water or an aqueous solution.

Description

[Technical Field]

[0001] The present invention relates to a ground grouting agent used in ground improvement work and water-stopping work in various civil engineering works, and a ground grouting method using the same. [Background technology]

[0002] Liquid-type ground grouting agents have been used to stabilize the natural ground and ground in tunnel construction, urban civil engineering, etc. These ground grouting agents include suspension-type ground grouting agents containing cement-based particles and solution-type ground grouting agents that do not contain cement-based particles.

[0003] While suspension-type grouting agents have the advantage of excellent strength development, they have the disadvantage that it is difficult for the chemical solution to penetrate dense sandy layers with small particle spacing.Furthermore, suspension-type grouting agents have a long time until they harden, i.e., their long gel time, which makes them unsuitable for watertight sealing.

[0004] On the other hand, polymeric grouting agents such as acrylamide and urethane have been used as solution-type ground grouting agents, but due to pollution problems caused by these chemical solutions flowing into well water, the former Ministry of Construction issued the "Provisional Guidelines for Construction Work Using Chemical Grouting Methods" in 1974, which put a freeze on the use of polymeric grouting agents, and there has been a demand for safer and more efficient ground grouting agents.

[0005] From this perspective, the solution-type ground grouting agents currently in use are of the type that use a base agent such as water glass and reactants such as inorganic salts that dissolve in water, organic solutions, acids, and alkaline solutions, either singly or in combination. For example, inorganic salts include carbonates, chlorides, sulfates, borates, and phosphates, while organic solutions include mixtures of esters and monoether glycol acetate, propylene carbonate, mixtures of aldehydes and formaldehyde, methyl formate, and glyoxal. Sulfuric acid is commonly used as the acid, and various inorganic hydroxides are used as the alkaline solution.

[0006] As described above, solution-type ground grouting agents have excellent permeability because they are a solution without particles, but some tend to leak out of the hardened body after hardening, and many lack dimensional stability. Also, some require careful handling depending on the type of reactant (see Patent Documents 1, 2, 3, 4, 5, and 6). Furthermore, because aluminates, silicates, and calcium aluminates act as cement hydration accelerators, injection agents containing these have also been proposed (see Patent Documents 7 to 14). Furthermore, silicates with a high molar ratio of SiO2 to Na2O (SiO2 / Na2O) have been proposed in the form of solutions. However, if the injection agent cracks, it has little effect on repairing the cracks, and there is a problem that water leakage may occur again after injection. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Publication No. 52-113505 [Patent Document 2] Japanese Patent Application Publication No. 57-047226 [Patent Document 3] Japanese Patent Application Publication No. 52-087807 [Patent Document 4] Japanese Patent Application Publication No. 51-082913 [Patent Document 5] Japanese Patent Publication No. 52-120507 [Patent Document 6] Japanese Patent Application Publication No. 57-195786 [Patent Document 7] Japanese Patent Application Laid-Open No. 2013-147630 [Patent Document 8] Japanese Patent Application Laid-Open No. 2008-144017 [Patent Document 9] Japanese Patent Application Laid-Open No. 2008-144015 [Patent Document 10] Japanese Patent Application Laid-Open No. 2005-139368 [Patent Document 11] Japanese Patent Application Publication No. 09-157649 [Patent Document 12] Special Publication No. 02-293363 [Patent Document 13] Special Publication No. 02-293364 [Patent Document 14] Japanese Patent Application Laid-Open No. 2005-146161 Summary of the Invention [Problem to be solved by the invention]

[0008] An object of the present invention is to provide a ground grouting agent that has excellent permeability, high gel strength, and excellent crack repair properties. [Means for solving the problem]

[0009] As a result of extensive investigations, the present inventors have found that the above-mentioned problems can be solved by using two specific reactants, and have thus completed the present invention.

[0010] [1] A ground grouting agent consisting of Agent A containing cement in water or an aqueous solution, and Agent B, which is prepared by blending sodium silicate powder in water or an aqueous solution, in which the molar ratio of SiO2 to Na2O (SiO2 / Na2O) is 0.5 to 1.5 and the number of waters of hydration is 9 or less. [2] The ground grouting agent according to [1], wherein the sodium silicate powder is contained in an amount of 0.1 to 30 parts by mass per 100 parts by mass of the cement. [3] The ground grouting agent according to [1] or [2], wherein the agent B contains alum in an amount of 0.1 to 30 parts by mass per 100 parts by mass of the cement. [4] The ground grouting agent according to any one of [1] to [3], wherein the agent A contains an alkaline earth metal salt in an amount of 0.1 to 30 parts by mass per 100 parts by mass of the cement. [5] The ground grouting agent according to any one of [1] to [4], wherein the agent A contains an alkali metal carbonate in an amount of 0.1 to 30 parts by mass per 100 parts by mass of the cement. [6] The ground grouting agent according to any one of [1] to [5], wherein the mixing ratio of the agent A to the agent B is 30:70 to 90:10 by mass. [7] A ground injection method in which Agent A and Agent B described in any one of [1] to [6] are mixed before or after injection into the ground. [8] A ground injection method according to [7], in which the agent A and agent B are mixed and injected immediately before injection into the ground. [Effects of the Invention]

[0011] According to the present invention, it is possible to provide a ground grouting agent that has excellent permeability, high gel strength, and excellent crack repair properties, thereby improving the durability of the ground after injection, for example. DETAILED DESCRIPTION OF THE INVENTION

[0012] The ground grouting agent of the present invention comprises Agent A containing cement in water or an aqueous solution, and Agent B obtained by blending sodium silicate powder, in water or an aqueous solution, in which the molar ratio of SiO2 to Na2O (SiO2 / Na2O) is 0.5 to 1.5 and the number of waters of hydration is 9 or less. The ground grouting method of the present invention is a ground grouting method in which Agent A and Agent B are mixed before or after injection into the ground. Hereinafter, an embodiment of the present invention (the present embodiment) will be described in more detail. In this specification, parts and % are by mass unless otherwise specified.

[0013] [1. Ground grouting agent] (cement) The cement used in this embodiment is not particularly limited, and examples include various cements such as normal, early-strength, ultra-early-strength, low-heat, and medium-heat cements, various mixed cements obtained by mixing these cements with blast furnace slag, fly ash, silica fume, etc., environmentally friendly cements (ecocement) produced using municipal waste incineration ash or sewage sludge incineration ash as raw materials, commercially available fine particle cements, etc. It is also possible to use various cements and various mixed cements that have been finely powdered. Also, cements that have been adjusted by increasing or decreasing the amount of components (such as gypsum) used in regular cements can be used.

[0014] (sodium silicate powder) The sodium silicate powder used in this embodiment primarily promotes the loss of fluidity in the very early stages. For example, when cracks develop in the applied grout over time, it can repair cracks of, say, 0.1 mm in size under running water conditions. This is thought to be because the sodium silicate gels with water, repairing the cracks themselves and narrowing their width. To efficiently achieve this effect, the sodium silicate is powdered, and the molar ratio of SiO2 to Na2O (SiO2 / Na2O) is 0.5 to 1.5.

[0015] The sodium silicate powder may be in a powder state at least before blending, and at least a part of it may be dissolved after blending.

[0016] As a ground grouting agent, for example, one that promotes loss of fluidity in the very early stages, the molar ratio of SiO2 to Na2O (SiO2 / Na2O) in sodium silicate is 0.5 to 1.5, preferably 0.9 to 1.3. When the molar ratio is 0.5 or more, the powder is easy to handle, and when it is 1.5 or less, there is a significant loss of fluidity immediately after addition, and early strength development and crack repair properties are easily obtained.

[0017] Examples of sodium silicate in the sodium silicate powder include sodium orthosilicate, sodium metasilicate, and sodium sesquisilicate, with sodium metasilicate being preferred. The sodium silicate powder is not particularly limited and may be either hydrated or anhydrous, but the number of water of hydration is 9 or less, preferably 5 or less, and the use of anhydrous sodium silicate is more preferred. The Blaine specific surface area of ​​sodium silicate powder is 300 to 1000 cm 2 / g, and 500 to 800 cm 2 / g. 2 / g, initial strength development is easily obtained.

[0018] The amount of sodium silicate powder used is preferably 0.1 to 30 parts, more preferably 0.2 to 10 parts, per 100 parts of cement. When the amount is 0.1 part or more, the thickening effect after filling and crack repair ability tend to be more sufficient, while when the amount is 30 parts or less, the thickening effect is prevented from being too great, making pumping difficult, and long-term strength development can be improved.

[0019] (alkaline earth metal salts) The alkaline earth metal salt (hereinafter referred to as metal salt) used in this embodiment promotes loss of fluidity in the very early stage, and refers to alkaline earth hydroxides or alkaline earth metal salts, and one or more of these can be used.

[0020] The alkaline earth metal salt is not particularly limited, but calcium or magnesium salts are preferred, and calcium hydroxide or magnesium hydroxide is more preferred. The alkaline earth metal salt is preferably mixed with Agent A, and the amount used is preferably 0.1 to 30 parts, more preferably 0.2 to 10 parts, per 100 parts of cement. An amount of 0.1 part or more tends to ensure a sufficient thickening effect after filling, while an amount of 30 parts or less prevents the thickening effect from being too great, making pumping difficult, and improves long-term strength development.

[0021] (alkali metal carbonate) Examples of alkali metal carbonates (hereinafter referred to as carbonates) used in this embodiment include sodium carbonate, potassium carbonate, lithium carbonate, sodium bicarbonate, potassium bicarbonate, sodium sesquicarbonate, etc., and one or more of these may be used. Among these, potassium carbonate is preferred because it has a significant effect of increasing strength after filling.

[0022] The carbonate is preferably mixed with Agent A, and the amount used is preferably 0.1 to 30 parts, more preferably 0.2 to 10 parts, per 100 parts of cement. When the amount is 0.1 part or more, the strength-enhancing effect tends to be more sufficient, and when the amount is 30 parts or less, the long-term strength development can be improved.

[0023] (Alum) The alum used in this embodiment is effective in further promoting the loss of fluidity in the very early stages and in promoting strength development over about one day. The alum is not particularly limited, and any alum, such as potassium alum, chrome alum, iron alum, ammonium alum, sodium alum, or natural alum, can be used or used in combination. It is particularly preferable to include at least one alum selected from the group consisting of potassium alum, sodium alum, and ammonium alum.

[0024] Alum is preferably mixed with Agent B, and the amount used is preferably 0.1 to 30 parts, more preferably 0.1 to 15 parts, and even more preferably 0.2 to 10 parts, per 100 parts of cement. By setting the content to 0.1 to 30 parts, loss of fluidity is not delayed and strength development at one day of age can be improved.

[0025] The Blaine specific surface area of ​​alum is set to 300 to 1000 cm in order to enhance the effect of promoting the loss of fluidity in the very early stage. 2 / g, and 500 to 900 cm 2 / g is more preferred.

[0026] Agent A contains cement in water or an aqueous solution, and Agent B contains sodium silicate powder mixed in water or an aqueous solution. In each case, the "aqueous solution" refers not only to pure water but also to various liquids (acidic solution, alkaline solution, organic solution, etc.) and solutions containing additives.

[0027] In this embodiment, various additives may be added in addition to the above components. For example, phosphates, organic acids, etc. may be added to Agent A and / or Agent B.

[0028] (phosphate) The phosphate used in this embodiment may be any of monosodium phosphate, disodium phosphate, trisodium phosphate, sodium pyrophosphate, sodium tripolyphosphate, sodium trimetaphosphate, sodium hexametaphosphate, sodium ultraphosphate, and sodium tetrapolyphosphate, or potassium salts thereof, etc. Among these, sodium tripolyphosphate is preferred from the viewpoint of strength development.

[0029] The amount of phosphate used is preferably 0.1 to 15 parts, more preferably 0.2 to 7 parts, per 100 parts of cement. When the amount is 0.1 part or more, it becomes easier to adjust the setting time more sufficiently, and when the amount is 15 parts or less, it becomes possible to improve strength development.

[0030] (organic acid) The organic acid used in this embodiment has the effect of adjusting the setting. As the organic acid, any of citric acid, tartaric acid, gluconic acid, malic acid, and their sodium or potassium salts can be used, but sodium citrate is preferred because it does not inhibit the strength development. One or more of these can be used.

[0031] The amount of organic acid used is preferably 0.1 to 15 parts, more preferably 0.2 to 7 parts, per 100 parts of cement. When the amount is 0.1 part or more, it becomes easier to adjust the setting time more sufficiently, and when the amount is 15 parts or less, it becomes possible to improve strength development.

[0032] Prior to mixing Agent A and Agent B, the solids concentration of Agent A is preferably 50 to 150 parts, more preferably 80 to 120 parts, per 100 parts of water. The solids concentration of Agent B is preferably 4 to 70 parts, more preferably 5 to 30 parts, per 100 parts of water. The total solids concentration of Agent A and Agent B is preferably 20 to 70 parts, more preferably 30 to 60 parts, per 100 parts of water. Within the above ranges, there is little outflow of the solution after curing, and a good cured state and appropriate viscosity are obtained.

[0033] By using the ground grouting agent of the present invention as described above, the above-mentioned problems can be solved, and in particular, effects such as rapid initial hardening, high gel strength, and excellent crack repair rate can be achieved.

[0034] [2.Ground injection method] The ground injection method according to this embodiment is a ground injection method in which the aforementioned agents A and B are mixed before or after injection into the ground. For example, agents A and B are pumped separately and mixed (in the ground) before or after injection into the ground. To more easily achieve the effects of the present invention, it is preferable to mix and inject agents A and B immediately before injection into the ground. For example, it is preferable to mix agents A and B and inject them by known means within 0.5 minutes.

[0035] In this embodiment, the mixing ratio of agent A to agent B is preferably 30:70 to 90:10 by mass, and more preferably 40:60 to 80:20. Within the above ratio range, gelation can be more effectively achieved, making it easier to obtain excellent gel strength. Furthermore, any equipment can be used to mix agent A and agent B as long as it can mix them uniformly. [Example]

[0036] The present invention will be described below based on experimental examples, but the present invention is not limited to these.

[0037] [Experimental Example 1] Agents A and B were prepared (preparation of ground grouting agents) by adding sodium silicate, alkaline earth metal salts, alkali metal carbonates, and alum with varying molar ratios of SiO2 to Na2O (SiO2 / Na2O) and numbers of water of hydration to 100 parts by mass of cement in the proportions shown in Tables 1 to 3. The solids concentration of Agent A was 100 parts per 100 parts of water, and the solids concentration of Agent B was 10 parts per 100 parts of water. Here, Agent A contains 100 parts by mass of cement, alkaline earth metal salt, alkali metal carbonate, and water in the proportions shown in Tables 1 to 3, and Agent B contains sodium silicate, alum, and water in the proportions shown in Tables 1 to 3. In addition, in all the experiments except for Experiment No. 1-0, 0.5 parts by mass of sodium monophosphate and 0.2 parts by mass of sodium citrate were mixed with Agent A relative to 100 parts by mass of cement. Furthermore, a ground adjustment agent was prepared in the same manner as in Experiment No. 1-0, except that Agent A contained 100 parts by mass of cement and Agent B contained sodium silicate in the proportions shown in Table 1, and the tests described below were also conducted on this agent (Experiment No. 0-0).

[0038] Agent A and agent B were mixed in a mass ratio of 60:40 in a room at 20°C and a relative humidity of 80%, and the gel time, gel strength, and crack repair rate were measured and shown in Tables 1 to 3.

[0039] The materials used are as follows: <Materials used> Cement A: Ordinary Portland cement, Blaine specific surface area 3340 cm 2 / g Alkaline earth metal salts a: calcium hydroxide, commercially available Alkaline earth metal salt B: Magnesium hydroxide, commercially available Alkaline earth metal salt c: Calcium chloride, commercially available

[0040] Alkali metal carbonate a: potassium carbonate, commercially available Alkali metal carbonate b: Sodium carbonate, commercially available Alum a: Potassium alum dodecahydrate, commercially available, Blaine specific surface area 600 cm 2 / g Alum b: Sodium aluminum sulfate dodecahydrate, commercially available, Blaine specific surface area 700 cm 2 / g Alum c: Ammonium alum dodecahydrate, commercially available, Blaine specific surface area 600 cm 2 / g

[0041] Sodium phosphate monobasic: first-class reagent Sodium citrate: First-class reagent Water: Tap water

[0042] <Measurement method> (1) Gel time: After mixing Agent A and Agent B, a small amount was transferred to a cup. The gel time was the time when the mixture became significantly thicker and difficult to flow (when the cup was tilted 60 degrees and it could no longer maintain its shape). The shorter the gel time, the less likely the mixture is to flow into water-filled ground, and the better the injectability.

[0043] (2) Gel strength: The strength of the cured product 6 hours after the gel time was measured in accordance with JIS A 5201. 2 Above: ◎, 0.5kgf / cm 2 More than 1kgf / cm 2 If less than 0.5kgf / cm, it is OK. 2 If it was less than this, it was marked as △. ◎ and ○ are acceptable.

[0044] (3) Crack repair rate: A mixture of Agents A and B was poured into a 4cm x 4cm x 16cm mold to prepare a test specimen. After 28 days of age, a bending test was conducted on the test specimen. A 0.1mm spacer was placed in the center of the specimen to reduce the crack width to 0.1mm, and the specimen was then fixed in a vice. The specimen was then cured underwater at 20°C for 12 months, and the specimen was observed under a microscope to determine the repair rate for a 0.1mm gap. It is preferable that the crack repair rate be 50% or more.

[0045] [Table 1]

[0046] [Table 2]

[0047] [Table 3]

[0048] It is clear that the use of the ground grouting agent of the present invention results in rapid initial hardening, excellent strength development, and excellent crack repair rate.

[0049] [Experimental Example 2] The soil grouting agents (agents A and B) of Experiments No. 1-4 were used, and the gel time, gel strength, and crack repair rate were measured in the same manner as in Experiment 1, except that agents A and B were used in the ratios shown in Table 4 below. The results are also shown in Table 4.

[0050] [Table 4]

[0051] Table 4 shows that by using a ground grouting agent with a mass ratio of agent A to agent B of 30:70 to 90:10, the initial hardening is rapid, and the strength development and crack repair rate are particularly excellent. [Industrial Applicability]

[0052] The ground grouting agent and the ground grouting method using the same of the present invention can be widely used in ground improvement works and water-stopping works in various civil engineering works.

Claims

1. A component A contains cement in water or an aqueous solution, and SiO ２ and Na ２ Molar ratio of SiO ２ / Na ２ and agent B, which is obtained by blending sodium silicate powder having a saturation index (Sr) of 0.5 to 1.5 and a number of water of hydration of 9 or less in water or an aqueous solution, The solid content concentration of the agent B is 4 to 70 parts by mass per 100 parts by mass of water, A ground grouting agent in which the sodium silicate powder is 0.2 to 30 parts by mass per 100 parts by mass of the cement (excluding cases where a water-soluble vinyl copolymer having a mass average molecular weight of 2,000 to 50,000 obtained by alkaline hydrolysis of a copolymer of an olefin having 3 to 8 carbon atoms and maleic anhydride is contained).

2. 2. The ground grouting agent according to claim 1, wherein the agent B contains 0.1 to 30 parts by mass of alum per 100 parts by mass of the cement.

3. 3. The ground grouting agent according to claim 1, wherein the agent A contains an alkaline earth metal salt in an amount of 0.1 to 30 parts by mass per 100 parts by mass of the cement.

4. 4. The ground grouting agent according to claim 1, wherein the agent A contains an alkali metal carbonate in an amount of 0.1 to 30 parts by mass per 100 parts by mass of the cement.

5. The ground grouting agent according to any one of claims 1 to 4, wherein the mixing ratio of the agent A to the agent B is 30:70 to 90:10 by mass ratio.

6. A ground injection method comprising mixing the agent A and the agent B according to any one of claims 1 to 5 before or after injection into the ground.

7. 7. The ground grouting method according to claim 6, wherein the agent A and agent B are mixed and injected immediately before injection into the ground.

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