Grout material

Abstract

The challenge is to provide grouting materials that can reduce CO2 emissions. [Solution] The grout material according to the present invention is a grout material consisting of two liquids, liquid A and liquid B, wherein liquid A contains blast furnace slag fine powder, an irritant, and water, and liquid B contains a plasticizer. In the grout material according to the present invention, the irritant contains at least one of the following: slaked lime, expansive agent, Portland cement, blast furnace cement, silica cement, fly ash cement, concrete rapid strengthening agent, and hardening accelerator, and when the total volume of liquid A and liquid B is 1000 L, the content of blast furnace slag fine powder is 180.0 to 245.0 kg, and the content of the irritant is 25.0 to 95.0 kg.

Description

Technical Field

[0001] The present invention relates to a two-component and plastic grout material.

Background Art

[0002] Of the CO2 emissions resulting from the production of materials such as concrete and mortar, nearly 90% is based on the production of Portland cement. Therefore, by using blast furnace slag fine powder or the like instead of Portland cement, the CO2 emissions can be significantly reduced.

[0003] The applicant of the present application has proposed in Patent Document 1 a technique that exhibits properties (such as strength) equivalent to those of ordinary cement even when a large amount of blast furnace slag fine powder is used. According to the invention according to Patent Document 1, since a large amount of blast furnace slag fine powder is used, the amount of Portland cement used can be reduced (or can be made zero), contributing to the reduction of CO2 emissions.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In shield tunnel construction, in order to prevent the subsidence and collapse of the ground, a shield plastic injection method is used in which a plastic grout material (shield backfill injection material) is injected between the excavation wall surface and the formwork (segment). As one of the grout materials used here, a two-component and plastic grout material composed of liquid A and liquid B can be mentioned. Currently, Portland cement is used as the main material for liquid A. The inventors of this invention wanted to create a new grout material that could contribute to reducing CO2 emissions, similar to the one described in Patent Document 1.

[0006] Therefore, the object of the present invention is to provide a grout material that can reduce CO2 emissions. [Means for solving the problem]

[0007] The aforementioned problem can be solved by the following means. The grout material according to the present invention is a grout material consisting of two liquids, liquid A and liquid B, wherein liquid A contains blast furnace slag fine powder, an irritant, and water, and liquid B contains a plasticizer. According to the present invention, since the grout material A does not require Portland cement, the amount of Portland cement used can be reduced, and CO2 emissions associated with this reduction in usage can be reduced. The grout material according to the present invention contains at least one of the following as the stimulant: slaked lime, expansive agent, Portland cement, blast furnace cement, silica cement, fly ash cement, concrete rapid strengthening agent, and hardening accelerator. When the total volume of liquid A and liquid B is 1000 L, the blast furnace slag fine powder content is 180.0 to 245.0 kg, and the stimulant content is 25.0 to 95.0 kg. Furthermore, the grout material according to the present invention contains slaked lime and expansive agent as the stimulant. When the total volume of liquid A and liquid B is 1000 L, the slaked lime content is 25.0 to 65.0 kg, and the expansive agent content is 50.0 kg or less. Furthermore, in the grout material according to the present invention, the A liquid contains calcium carbonate (CaCO3), and when the total volume of the A liquid and the B liquid is 1000 L, the calcium carbonate (CaCO3) content is 40.0 kg or less. Furthermore, in the grout material according to the present invention, the A liquid contains bentonite and a retarder, and when the total volume of the A liquid and the B liquid is 1000 L, the bentonite content is 15.0 to 30.0 kg and the retarder content is 1.0 to 5.0 kg. Furthermore, in the grout material according to the present invention, the volume ratio of the A liquid to the B liquid is 9.5 to 8.5:0.5 to 1.5 (when the total volume ratio is 10). According to the present invention, while reducing CO2 emissions as described above, excellent results can be achieved in terms of various indicators required for grout materials, such as "uniaxial compressive strength," "gel time," and "flow of liquid A." [Effects of the Invention]

[0008] The grout material according to the present invention can reduce CO2 emissions. [Brief explanation of the drawing]

[0009] [Figure 1] This graph shows the relationship between the amount of blast furnace slag and the unconfined compressive strength (age 1 hour) in the example. [Figure 2] This graph shows the relationship between the amount of stimulant and the uniaxial compressive strength (at 1 hour of age) in the examples. [Modes for carrying out the invention]

[0010] The following describes embodiments for implementing the grout material according to the present invention. [Grout material] The grout material according to this embodiment is a grout material consisting of two liquids, liquid A and liquid B, wherein liquid A contains blast furnace slag fine powder, an irritant, and water, and liquid B contains a plasticizer. Liquid A may also optionally contain calcium carbonate (CaCO3), auxiliary materials (such as bentonite), and stabilizers (such as retarders). The grout material according to this embodiment is composed of two liquids, liquid A and liquid B, and is used for injection into tunnel linings, retaining walls, etc., and is therefore called a "two-component backfill material" or "two-component backfill injection material." Liquid A is a suspension that forms the main component of the grout material, and liquid B is an aqueous solution that reacts with liquid A to act as a plasticizer or gelling agent. The following describes in detail each component that makes up the grout material according to this embodiment.

[0011] (Blast furnace slag fine powder) Blast furnace slag fine powder refers to blast furnace granulated slag that has been dried and pulverized, or to which gypsum has been added, as specified in JIS A6206:2013. In this embodiment, liquid A of the grout material contains blast furnace slag fine powder as a substitute (partially or entirely) for Portland cement, thereby contributing to the reduction of CO2 emissions. Furthermore, the blast furnace slag fine powder may be mixed with industrial by-products or natural materials with limited utilization, such as fly ash (JIS A6201:2015), volcanic glass (JIS A6209:2020), and silica fume (JIS A6207:2016), which can contribute to resource recycling. The blast furnace slag fine powder content is preferably 180.0 kg or more, more preferably 182.0 kg or more, and more preferably 184.0 kg or more, when the total volume of liquids A and B is 1000 L. By having a blast furnace slag fine powder content above the predetermined value, the amount of Portland cement used can be reduced (or eliminated), thereby reducing CO2 emissions. The content of blast furnace slag fine powder is preferably 245.0 kg or less, more preferably 243.0 kg or less, and more preferably 240.0 kg or less, when the total volume of liquids A and B is 1000 L. By keeping the content of blast furnace slag fine powder below a predetermined value, the various effects caused by the other materials described later (shortened gel time, favorable flow of liquid A, and excellent uniaxial compressive strength) can be achieved.

[0012] (Stimulant) A stimulant is a material that promotes hardening, and for example, materials mainly composed of alkali metal, alkaline earth metal, or magnesium hydroxide, carbonate, bicarbonate, sulfate, nitrate, or silicate can be used. Preferably, a material that elutes calcium ions is used, such as slaked lime or quicklime whose main component is calcium hydroxide by the time of mixing, various Portland cements (JIS R5210) or ecocement (JIS R5214), blast furnace cement (JIS R5211) or silica cement (JIS R5212) or fly ash cement (JIS R5213), concrete expansives (JIS A6202), concrete rapid strengthening agents or hardening accelerators (JIS A6204), etc. More preferably, from among these stimulants, it is preferable to use multiple stimulants that have different rates of calcium ion elution in the material composition of the present invention. When multiple stimulants with different calcium ion elution rates are used, first, the stimulant with the faster calcium ion elution rate acts as a reaction stimulant for the blast furnace slag fine powder. Next, the supply of calcium ions eluted from the stimulant with the slower calcium ion elution rate ensures that a sufficient amount of calcium hydroxide and calcium silicate hydrate with a high Ca / Si ratio are present in the grout material. As a result, strength is increased and neutralization is suppressed. In this invention, examples of stimulants that rapidly release calcium ions include slaked lime and quicklime, while examples of stimulants that slowly release calcium ions include concrete expansives (JIS A6202), various Portland cements (JIS R5210), blast furnace cement (JIS R5211), silica cement (JIS R5212), fly ash cement (JIS R5213), and eco-cement (JIS R5214). Furthermore, the invention is not limited to the blended cements specified in JIS, but may also be a mixture of Portland cement (JIS R5210) with blast furnace slag powder (JIS A6206), fly ash (JIS A6201), volcanic glass (JIS A6209), or silica fume (JIS A6207).

[0013] The stimulant content (total content if multiple stimulants are used) is preferably 25.0 kg or more, more preferably 26.0 kg or more, and more preferably 27.0 kg or more, when the total volume of liquids A and B is 1000 L. By having a stimulant content above the predetermined value, the grout material can exhibit the various effects required (shortened gel time, favorable flow of liquid A, and excellent uniaxial compressive strength) in the embodiment using blast furnace slag fine powder. The stimulant content (total content if multiple stimulants are used) is preferably 95.0 kg or less, more preferably 92.0 kg or less, and more preferably 90.0 kg or less, when the total volume of solution A and solution B is 1000 L. By keeping the stimulant content below a predetermined value, a decrease in uniaxial compressive strength can be avoided.

[0014] The case where Liquid A of the grout material according to this embodiment contains slaked lime and an expansive material as stimulants will be described. Note that slaked lime is calcium hydroxide (Ca(OH)2), or it may be quicklime or calcium oxide (CaO) that becomes slaked lime when mixed with water. An expansive material is an admixture that has the effect of expanding concrete or mortar and is defined in JIS A6202. And the expansive material is, for example, a calcium-based expansive material. When the total volume of Liquid A and Liquid B is 1000 L, the content of slaked lime is preferably 25.0 kg or more, more preferably 26.0 kg or more, and even more preferably 27.0 kg or more. Also, when the total volume of Liquid A and Liquid B is 1000 L, the content of slaked lime is preferably 65.0 kg or less, more preferably 63.0 kg or less, and even more preferably 60.0 kg or less. When the total volume of Liquid A and Liquid B is 1000 L, the content of the expansive material is preferably 50.0 kg or less, more preferably 48.0 kg or less, and even more preferably 45.0 kg or less. Also, when the total volume of Liquid A and Liquid B is 1000 L, the content of the expansive material may be 0.0 kg (it may not be included), but for example, it is 15.0 kg or more, 17.0 kg or more, or 20.0 kg or more. By having the content of slaked lime and the content of the expansive material be above a predetermined value, in the mode of using blast furnace slag fine powder, each effect required for the grout material (shortening of the gel time, suitable flow of Liquid A, excellent uniaxial compressive strength) can be exhibited. Also, by having the content of slaked lime and the content of the expansive material be below a predetermined value, a decrease in uniaxial compressive strength can be avoided.

[0015] (Calcium carbonate (CaCO3)) Calcium carbonate (CaCO3) can be used, for example, as heavy calcium carbonate (CaCO3) obtained by pulverizing and classifying limestone, natural calcium carbonate called limestone fine powder, and synthetic calcium carbonate called light calcium carbonate obtained by precipitating fine crystals through a chemical reaction. Note that calcium carbonate produced by recovering or absorbing CO2 contained in the atmosphere or exhaust gas, etc., can also be treated as light calcium carbonate because it is synthesized by the reaction of calcium and CO2. When the total volume of liquid A and liquid B is 1000 L, the content of calcium carbonate (CaCO3) is preferably 40.0 kg or less, more preferably 35.0 kg or less, and even more preferably 30.0 kg or less. By having the content of calcium carbonate (CaCO3) below a predetermined value, it is possible to avoid a situation where the flow of liquid A becomes inappropriate. When the total volume of liquid A and liquid B is 1000 L, the content of calcium carbonate (CaCO3) may be 0.0 kg (it may not be contained), but for example, it is 20.0 kg or more, 25.0 kg or more, 27.0 kg or more. By having the content of calcium carbonate (CaCO3) above a predetermined value, it is possible to shorten the gel time and more strongly exhibit excellent uniaxial compressive strength.

[0016] Note that the above-mentioned "blast furnace slag fine powder", "stimulating agent" (such as slaked lime and expansive material), and "calcium carbonate" are materials that cause a gelation reaction with a plasticizer (liquid B) such as water glass described later and solidify, and thus are generally also called "hardening materials".

[0017] (Admixture) An admixture is a material that improves the resistance to material separation in order to enable proper pumping of liquid A. For example, it corresponds to raw minerals and clay minerals that are fine particles, and specifically, quartz, limestone, bentonite, etc. can be mentioned. The case where liquid A of the grout material according to this embodiment contains bentonite as an admixture will be described. Note that bentonite is a general term for clay rocks mainly composed of montmorillonite. The bentonite content is preferably 15.0 kg or more, more preferably 18.0 kg or more, and more preferably 20.0 kg or more, when the total volume of liquid A and liquid B is 1000 L. Furthermore, the bentonite content is preferably 30.0 kg or less, more preferably 27.0 kg or less, and more preferably 25.0 kg or less, when the total volume of liquid A and liquid B is 1000 L.

[0018] (Stabilizer) Stabilizers are materials used to extend the pot life of solution A by suppressing the hydration reaction of blast furnace slag powder and stimulants, and they have delaying and dispersing effects. Examples include ligninsulfonic acid-based, carboxylic acid-based, and sucrose-based chemical admixtures. This section describes the case in which liquid A of the grout material according to this embodiment contains a retarder as a stabilizer. A retarder is an admixture used to delay the setting or initial hydration reaction. The content of the retarder is preferably 1.0 kg or more, more preferably 2.0 kg or more, and more preferably 2.5 kg or more, when the total volume of solution A and solution B is 1000 L. Furthermore, the content of the retarder is preferably 5.0 kg or less, more preferably 4.0 kg or less, and more preferably 3.5 kg or less, when the total volume of solution A and solution B is 1000 L.

[0019] (water) The water content in solution A is, for example, 600L or more, 700L or more, 850L or less, and 800L or less, assuming the total volume of solutions A and B is 1000L. Furthermore, there are no particular restrictions on the type of water used; tap water, groundwater, industrial water, etc., can be used.

[0020] (Other materials in Solution A) The grout material A in this embodiment may appropriately contain conventionally known materials used in A (for example, chemical admixtures specified in JIS A6204:2011) to the extent that the desired effects of the present invention are not hindered. It should be noted that the grout material A in this embodiment does not completely eliminate Portland cement (JIS R5210:2009), but naturally, from the viewpoint of reducing CO2 emissions, it is preferable to have a low Portland cement content, and even more preferable to have no Portland cement at all. The Portland cement content can be reduced by reducing the use of Portland cement, or by replacing it with a blended cement or an equivalent mixture while maintaining the same amount of cement.

[0021] (Plasticizer) The plasticizer used in solution B is mainly composed of water glass. Water glass is a material represented by the chemical formula Na2O·nSiO2·xH2O. For example, it may be sodium silicate (sodium silicate) as shown in JIS K1408, or powdered sodium metasilicate dissolved in water.

[0022] (Other materials in Solution B) In this embodiment, the grout material B may be water glass with different compositions and specific gravities, as long as the desired effects of the present invention are not hindered.

[0023] (Liquid A:Liquid B) In this embodiment, the volume ratio of liquid A to liquid B in the grout material is preferably 9.5 to 8.5:0.5 to 1.5 (when the total is 10). By keeping the volume ratio of solution A to solution B within a predetermined range, each effect (shortening of gel time, optimal flow of solution A, and excellent uniaxial compressive strength) can be more reliably achieved.

[0024] [How to use grout material] The manner in which the grout material according to this embodiment is used is not particularly limited, but it may be used based on a general shield plastic grouting method. For example, liquid A and liquid B are pumped to the target cavity through separate pipes, merged and mixed near the cavity, and the plasticized grout material is injected into the cavity. [Examples]

[0025] [material] Table 1 shows the formulations of each sample used in the examples. The materials shown in Table 1 are as follows: BFS (Blast Furnace Slag Fine Powder): Blast Furnace Slag 4000 (Esment 40G2), Nippon Steel Slag Kimitsu Plant, JIS A6206 St (slaked lime): Special Grade, Ube Materials, JIS R9001 St (Expanding agent): Taiheiyo NE-X, Taiheiyo Materials, JISA6202 Calcium carbonate (CaCO3): Limestone fine powder 100 mesh, Ube Materials, JIS R5210 Auxiliary material (bentonite): TW-Auxiliary material (powder), Bensan Engineering (Manufacturer: Hojun) Stabilizer (Retardant): TW-Stabilizer (Liquid) (3) Standard Product (Lignin Sulfonic Acid Type), Bensan Engineering Water: Tap water Liquid B: Plasticizer, Water Glass No. 3 (Specific Gravity 1.37), Bensan Engineering (Manufacturer: Toso Sangyo / Toyo Keisan Kogyo) Note that the total volume of Solution A and Solution B for all samples shown in Table 1 is standardized to 1000 L.

[0026] (Exam content: Gel Time) The "gel time," which indicates the time required for gelation, was determined by testing based on the following cup inversion method (see page 44 of the revised 5th edition of the "Shield Plastic Injection Method Technical Manual" by the Shield Injection Subcommittee of the Plastic Grout Association). For each sample, solutions A and B were weighed into separate beakers. Solution A was added to the beaker containing solution B, and the mixture was immediately poured into the beaker containing solution A. This process was rapidly repeated until the gel stopped flowing, at which point it was defined as the gel time. Furthermore, a time of 20 seconds or less was considered a passing grade for the gel time.

[0027] (Test content: Flow of solution A) The "flow of liquid A," which indicates the fluidity, pumpability, and viscosity of liquid A, was tested based on the flow time measurement using the following P funnel (see pages 43-44 of the technical manual mentioned above). 1725 mL of solution A for each sample was placed in a P funnel (pre-backed flow cone) conforming to the specifications described in the technical manual mentioned above, and the flow time (seconds) was measured to determine the flow of solution A. Furthermore, a flow time of 8 to 12 seconds for solution A was considered acceptable.

[0028] (Test content: Uniaxial compressive strength test) Uniaxial compressive strength was determined by mixing solution A and solution B of each sample and conducting the test in accordance with the compressive strength test specified in JIS R5201:2015. Uniaxial compressive strength was also tested at 1 hour and 28 days of age. Furthermore, regarding uniaxial compressive strength, basically, the strength of the material filling the cavity should be equal to or greater than that of the natural ground, but the strength at 1 hour is 0.02 N / mm². 2 The sample passed the inspection. The strength at 28 days of age was 1.5 N / mm². 2 It is preferable if the above conditions are met.

[0029] The formulations and test results for each sample are shown in Table 1 below. Note that a "-" in the composition of Table 1 indicates that the material is not included. Also, some of the samples in Table 1 have not undergone some evaluation tests, but samples for which a pass / fail determination cannot be made are disclosed as reference examples.

[0030] [Table 1]

[0031] (Review of results) Table 1 shows all the test results, Figure 1 shows the relationship between blast furnace slag amount and unconfined compressive strength (age 1 hour), and Figure 2 shows the relationship between stimulant amount and unconfined compressive strength (age 1 hour). As shown in Table 1 and Figures 1 and 2, the content of each material in samples 6 and 8-40 met the predetermined range preferred in the present invention. Therefore, these samples passed all tests for "gel time," "flow of solution A," and "uniaxial compressive strength." In other words, it was found that even when samples 6, 8-40 contained blast furnace slag powder instead of Portland cement in liquid A, they could satisfy the performance requirements for grout material (two-component backfill material) (rapid gelation after mixing of the two components, pumpability of liquid A, and early strength development).

[0032] On the other hand, since the content of each material in samples 1-4 and 7 (excluding sample 5, which is a reference example) did not meet the predetermined range preferred in the present invention, one or more evaluations were rejected. The details are as follows. Sample 1 failed to meet the requirements for gel time and uniaxial compressive strength because the blast furnace slag powder content was considerably higher than the specified value. Samples 2-4 failed to meet the uniaxial compressive strength requirement because their blast furnace slag powder content exceeded the specified upper limit. Sample 7 failed to meet the uniaxial compressive strength requirement because its slaked lime content exceeded the specified upper limit.

Claims

1. A grout material consisting of two components, A and B. The aforementioned liquid A contains blast furnace slag fine powder, an irritant, and water. The aforementioned liquid B is a grout material characterized by containing a plasticizer.

2. The stimulant comprises at least one of the following: slaked lime, expansive agent, Portland cement, blast furnace cement, silica cement, fly ash cement, concrete rapid strengthening agent, and hardening accelerator. The grout material according to claim 1, characterized in that, when the total volume of liquid A and liquid B is 1000 L, the content of the blast furnace slag fine powder is 180.0 to 245.0 kg and the content of the stimulant is 25.0 to 95.0 kg.

3. The aforementioned stimulant comprises slaked lime and a leavening agent. The grout material according to claim 1 or 2, characterized in that, when the total volume of liquid A and liquid B is 1000 L, the content of slaked lime is 25.0 to 65.0 kg and the content of the expansive material is 50.0 kg or less.

4. The aforementioned solution A is calcium carbonate (CaCO3). ３ ) including, When the total volume of solution A and solution B is 1000 L, the calcium carbonate (CaCO3) ３ The grout material according to claim 1 or 2, characterized in that the content of ) is 40.0 kg or less.

5. The aforementioned solution A contains bentonite and a retarder. The grout material according to claim 1 or 2, characterized in that, when the total volume of liquid A and liquid B is 1000 L, the bentonite content is 15.0 to 30.0 kg and the retarder content is 1.0 to 5.0 kg.

6. The grout material according to claim 1 or 2, characterized in that the volume ratio of liquid A to liquid B is 9.5 to 8.5:0.5 to 1.5.

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