Thickening slag mortar and manufacturing method thereof

Abstract

To provide a manufacturing method of thickening slag mortar that can maintain long usable time while reducing bleeding and material separation during pumping by instantaneously thickening.SOLUTION: A manufacturing method of thickening slag mortar that contains at least slag powder, gypsum powder, filler, water glass and water, does not contain cement, and is used by pumping includes a slag mortar making process in which water is added to slag powder, gypsum powder, and filler to make slag mortar and a water glass adding and stirring process in which, after adding water glass to slag mortar made in the slag mortar making process to generate floc-like heterogeneous gel, the floc-like heterogeneous gel is crushed and refined by stirring to promote gelation.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a thickening slag mortar and a method for producing the same. [Background technology]

[0002] Conventionally, for the purpose of ground improvement, various materials have been proposed and put into practical use, which have sufficient fluidity when poured and exhibit appropriate strength after pouring so as not to interfere with excavation or driving of sheet piles, even in dewaterable or non-drainable soil (see, for example, Patent Documents 1 to 6).

[0003] However, the materials currently in practical use have the following problems. Cement slurry and chemical grout materials (LW Liquid: Labiles Wasserglas), which are mainly made of water glass and cement, have a high risk of bleeding and material separation, which can lead to blockage of pipes when pumped through them. In addition, physical properties such as volume and density change during use, making it difficult to ensure the desired performance. · Cement-bentonite liquid requires the addition of a large amount of bentonite to achieve high material separation resistance, which increases the cost. Increasing the amount of cement per unit volume to prevent bleeding and material separation shortens the pot life and makes the strength greater than necessary. In mechanical mixing methods for block, wall, and grid-type improvement, if lap construction is to be performed several days later, a retarder is added to the cement-based solidification material. However, if too much retarder is added, poor hardening will occur. On the other hand, if an insufficient amount of retarder is added, or if the lap construction is significantly delayed due to bad weather or construction problems, the strength of the previously improved area will increase, resulting in poor construction at the joints. - Materials that use cement have a large environmental impact due to their high CO2 emissions. · Because slag powder has latent hydraulic properties, replacing part or all of the cement with slag powder can improve chemical resistance and seawater resistance, and reduce CO2 emissions. However, as the ratio of slag powder increases, bleeding and material separation increase, and hardening and strength development delay become more pronounced. Water glass is used as an alkaline stimulant to promote strength development, but with conventional usage, it is not possible to suppress bleeding and material separation because a flock-like non-uniform gel is not produced. Also, even if all of the cement is replaced with slag powder, its contribution to achieving carbon neutrality is small.

[0004] Incidentally, the inventions disclosed in the above Patent Documents 1 to 6 have the following problems. The adhesive grout of Patent Document 1 uses cement, and therefore the pot life cannot be sustained for a long period of time. The soil improvement solidification material of Patent Document 2 does not clearly state the order of addition or the method of addition and stirring, and the viscosity cannot be adjusted. The fluidized sand of Patent Document 3 emits a lot of CO2 because it is mixed with a large amount of slaked lime. In addition, since sand uses natural resources, there is an issue with sustainability. In the geopolymer of Patent Document 4, the alkaline solution is pre-diluted with 20 to 60 volume percent water, and a floc-like non-uniform gel is not produced, resulting in significant bleeding and material separation during pumping. The slurries in Patent Documents 5 and 6 emit a large amount of CO2 because they contain cement. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 6034530 [Patent Document 2] Patent No. 6968132 [Patent Document 3] Patent Publication No. 2021-25289 [Patent Document 4] Patent No. 6005408 [Patent Document 5] Patent No. 5590702 [Patent Document 6] Patent No. 6955967 Summary of the Invention [Problem to be solved by the invention]

[0006] In view of the problems inherent in the above-mentioned materials used for ground improvement, the first object of the present invention is to provide a thickening slag mortar that can instantly thicken to reduce bleeding and material separation during pumping while maintaining a long usable time, and a method for producing the same.

[0007] A second object of the present invention is to provide a thickening slag mortar that can reduce CO2 emissions. [Means for solving the problem]

[0008] In order to achieve the above-mentioned first object, the thickening slag mortar of the present invention contains at least slag powder, gypsum powder, filler, water glass and water, but does not contain cement, and is used by pumping, and is a thickening slag mortar that satisfies the following conditions (1) to (3). (1) The bleeding rate of the thickened slag mortar one hour after production is within 6%. (2) The table flow test value of the thickened slag mortar immediately after production, after shaking for one hour, and after shaking for three hours is 250 mm or more. (3) The uniaxial compression test value of the thickened slag mortar 28 days after production was 0.2MN / m 2 More than this Here, the thickening slag mortar can optionally contain admixtures for improving pumpability.

[0009] In order to achieve the same first object, the thickening slag mortar of the present invention contains at least aggregate, slag powder, gypsum powder, filler, water glass and water, but does not contain cement, and is used by pumping, and satisfies the following conditions (1) to (3). (1) The expansion / contraction rate after 28 days is greater than -3%. (2) The table flow test value of the thickening slag mortar immediately after production is 80 to 200 mm when left to stand, and 115 mm or more when struck. (3) The uniaxial compression test value of the thickened slag mortar 28 days after production was 0.2MN / m 2 More than this Here, the thickening slag mortar can optionally contain admixtures for improving pumpability.

[0010] In this case, the aggregate may be one or more selected from the group consisting of artificial aggregate, recycled aggregate, and crushed concrete sludge solid aggregate.

[0011] The filler may be one or more selected from the group consisting of light calcium carbonate, heavy calcium carbonate, and bentonite.

[0012] In order to achieve the second object, the light calcium carbonate is produced from an aqueous calcium hydroxide solution and carbon dioxide (CO2) as raw materials, and the thickening slag mortar is produced in an amount of 1 / 3. 3 CO2 emissions per unit can be -350 to 100 kg.

[0013] The gypsum powder may also be a mixture of anhydrous gypsum and dihydrate gypsum.

[0014] The water glass may have a molar ratio of silicic anhydride to sodium oxide of 2.0 to 3.2, and a concentration of sodium oxide of 9 to 15% by weight.

[0015] The fineness of the slag powder is 3500 to 5000 cm 2 / g.

[0016] In order to achieve the first object, the present invention provides a method for producing a thickening slag mortar, which contains at least slag powder, gypsum powder, a filler, water glass and water, does not contain cement, and is used by pumping, a slag mortar production step of adding water to the slag powder, the gypsum powder and the filler to produce slag mortar; a water glass addition and stirring step of adding water glass to the slag mortar generated in the slag mortar generation step to generate a floc-like heterogeneous gel, and then stirring the floc-like heterogeneous gel to crush and finely disperse it, thereby accelerating gelation; The present invention is characterized by comprising: In the method for producing the thickened slag mortar, an admixture for improving pumpability can be added as necessary.

[0017] In this case, aggregate can be further added in the slag mortar producing step.

[0018] In addition, aggregate can be added to the slag mortar produced in the water glass adding and stirring step and then stirred. Effect of the Invention

[0019] According to the thickening slag mortar and the manufacturing method thereof of the present invention, it is possible to provide a thickening slag mortar and a manufacturing method thereof that can instantly thicken to reduce bleeding and material separation during pumping while maintaining a long pot life. In addition, the uniaxial compressive strength can be adjusted to 0.2 to 30 MN / m depending on the application. 2 Since the composition can be adjusted to a desired value, it can be widely used in various construction methods aimed at ground improvement, etc. Also, depending on the application, an admixture for improving pumpability can be included as necessary, thereby improving the pumpability.

[0020] In addition, according to the thickening slag mortar of the present invention, by using light calcium carbonate produced from an aqueous calcium hydroxide solution and carbon dioxide (CO2) as raw materials, the thickening slag mortar can be made in an amount of 1 m. 3 This reduces CO2 emissions by -350~100 kg per unit, which helps reduce CO2 emissions and contributes to reducing the environmental impact. [Brief description of the drawings]

[0021] [Figure 1] FIG. 2 is a particle size distribution diagram of aggregate used in the thickening slag mortar of the present invention. [Diagram 2] FIG. 2 is a process diagram illustrating a method A for producing thickened slag mortar. [Diagram 3] FIG. 2 is a process diagram illustrating manufacturing method B of thickened slag mortar. [Figure 4] FIG. 2 is a process diagram illustrating manufacturing method C of thickened slag mortar. [Diagram 5] FIG. 2 is a process diagram illustrating manufacturing method D of thickened slag mortar. [Figure 6-1] Photographs showing the results of a table flow test. [Figure 6-2] Photographs showing the results of a table flow test. [Figure 7] FIG. 1 is a diagram showing the relationship between the stirring rotation speed and the bleeding rate when a propeller-type stirring blade and a paddle-type stirring blade are used, respectively. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] Hereinafter, an embodiment of the thickening slag mortar and the method for producing the same of the present invention will be described.

[0023] First, the constituent materials of the thickening slag mortar of the present invention, namely, aggregate, slag powder, gypsum powder, filler and water glass, will be described.

[0024] [aggregate] Table 1 and FIG. 1 show aggregates used in the thickened slag mortar of the present invention.

[0025] [Table 1]

[0026] Addition of aggregate (preferable amount of aggregate for thickening slag mortar: 0-1720kg / m 3 ) can improve economy and fluidity when pumped by a concrete pump. The aggregate can be one or more selected from artificial aggregate, recycled aggregate, and crushed concrete sludge solids. As no natural resources are used, this contributes to sustainability. Aggregate A and Aggregate B have latent hydraulic properties and can increase strength over the long term. On the other hand, aggregate C does not have latent hydraulic properties, and is therefore selected when it is desired to reduce strength or reduce the weight of the material.

[0027] [Slag powder] Table 2 shows the slag powders used.

[0028] [Table 2]

[0029] Add slag powder (preferable amount of slag powder added to thickening slag mortar: 20-1020 kg / m 3 ) to enhance strength. Specific surface area 3500~5000cm 2 Slag powder A and slag powder B were used because they are economical and easy to procure. However, the present invention is not limited to these, and the range of 5000 to 12000 cm 2 It was confirmed that slag powder of 1000 g / g has the same or better reactivity with water glass, and therefore the same or better performance can be obtained when this powder is used.

[0030] [Gypsum powder] The gypsum powder used may be a premix of anhydrite and gypsum with slag powder A. The amount of premix is Anhydrite: SO3=1.02wt% per slag powder Gypsum: SO3 per slag powder = 1.02wt% ·Anhydrite: Gypsum=1:1 It was decided. The amounts of additives other than those mentioned above are as follows: Anhydrite: SO3=1.02wt% per slag powder Gypsum: SO3 per slag powder = 1.02wt% The above was premixed, and then gypsum reagent was added to prepare a solution.

[0031] Gelling occurs due to the reaction of anhydrite and gypsum with the Na2O in water glass. Strength development occurs due to the reaction of the remaining Na2O consumed in gelation with the slag powder. Here, Anhydrite + Gypsum = SO3 per slag powder = 2-23wt% Anhydrite + Gypsum = SO3 per water glass = 6-72wt% ·Anhydrite: Gypsum=1:1~1:21 However, the ratio may be varied as long as the amount required to cause gelation is ensured.

[0032] [Filler] The filler used is one or more selected from light calcium carbonate, heavy calcium carbonate, and bentonite, but is not limited to these as long as it is a material that does not have latent hydraulic properties, and inorganic powders such as kaolinite, montmorillonite, illite, zeolite, fly ash, fine waste glass powder, and hydrated lime can also be used. Addition of these fillers (preferable amount of filler added to thickening slag mortar: 0 to 840 kg / m 3 ) to reduce the strength. By using light calcium carbonate as a filler, the viscosity of slag mortar is increased by 1m. 3 It is possible to achieve a CO2 emission per unit of production of 100 kg or less, preferably a negative value (specifically, -350 to 100 kg). When used as the primary grouting agent, the unconfined compressive strength must be 1MN / m in order not to impede the secondary grouting. 2 It is desirable that the level be less than this. If there is a possibility that the improved ground will be excavated in the future, the unconfined compressive strength must be 0.5MN / m so as not to interfere with the installation of earth retaining structures. 2 It is desirable that the level be less than this. The backfill material in the hole that remains after the underground pile is pulled out must have an unconfined compressive strength of 0.2 to 0.5 MN / m so that it has the same strength as the surrounding ground. 2 It is desirable that the degree of

[0033] [Light calcium carbonate (filler A)] Table 3 shows the precipitated calcium carbonate used.

[0034] [Table 3]

[0035] As the light calcium carbonate, one that has carbon dioxide immobilized by reacting highly alkaline wastewater generated in a secondary concrete product factory with carbon dioxide in the boiler exhaust gas (for example, product name: Eco Tankal) can be suitably used. Incidentally, light calcium carbonate derived from sources other than concrete sludge, such as by-products from the production of acetylene gas, by-products from the production of steel, waste concrete, etc., can also be used as the calcium source for the light calcium carbonate. The amount of CO2 fixed when producing 1 ton of precipitated calcium carbonate can be calculated by subtracting the amount of CO2 generated during the production of 1 ton of precipitated calcium carbonate from the amount of CO2 absorbed into the precipitated calcium carbonate. First, the amount of CO2 absorbed in the precipitated calcium carbonate can be calculated from its composition formula and molecular weight. The composition formula of precipitated calcium carbonate is CaCO3, and its molecular weight is 100g / mol, of which the molecular weight of CO2 is 44g / mol. From this, the proportion of CO2 in CaCO3 can be calculated to be 44%. In other words, by producing 1 ton of precipitated calcium carbonate, 440 kg of CO2 can be fixed. On the other hand, the amount of CO2 generated in the production of 1 ton of precipitated calcium carbonate is estimated to be about 50 kg. This is calculated from the power consumption of the equipment that produces precipitated calcium carbonate. From this, the net amount of CO2 fixed when producing 1 ton of precipitated calcium carbonate can be calculated as 440kg-50kg=390kg. The amount of light calcium carbonate used is calculated by adding up the CO2 emissions during the production of each material and calculating the total CO2 emissions per 1 m of thickening slag mortar. 3 The basic rule is to add an amount that reduces CO2 emissions per unit of production to 100 kg or less, preferably to a negative value (specifically, -350 to 100 kg).

[0036] [Heavy calcium carbonate (filler B)] Table 4 shows the ground calcium carbonate used.

[0037] [Table 4]

[0038] [Bentonite (filler C)] Table 5 shows the bentonite used.

[0039] [Table 5]

[0040] [Water glass] Sodium silicate is generally expressed by the formula Na2O·nSiO2·xH2O and comes in the following types: ·Sodium silicate anhydrous (cullet)··Solid ·Hydrated sodium silicate (powdered sodium silicate)··Solid ·Crystalline sodium silicate (sodium metasilicate, etc.) ·Solid Liquid sodium silicate (water glass) Liquid (aqueous solution) The liquid sodium silicate (water glass) used in the present invention (referred to as "water glass" in this specification) is produced by dissolving anhydrous sodium silicate (cullet), which is produced by melting silica sand and an alkali source (soda ash, caustic soda, etc.). Table 6 shows the types of water glass.

[0041] [Table 6]

[0042] The reaction of water glass is as follows: Reaction with acids: When acid is added to water glass, polymerization of silicate ions progresses and the water glass solidifies into a gel. Na2O·nSiO2+H2SO4→nSiO2·H2O(silicic acid gel)+NaSO4 Reaction with polyvalent metal ions: Water glass reacts with polyvalent metals such as Ca, Mg, Al, and Ba to produce an insoluble silicate gel. Na2O·nSiO2+Ca(OH)2→CaO·nSiO2+2NaOH Na2O·nSiO2+CaSO4→CaO·nSiO2+2Na2SO4 When water glass is added to a mixture of gypsum and slag, the water glass reacts with the gypsum, causing the mixture of gypsum and slag to gel. In this case, the amount of reaction is determined by the amount of gypsum and the concentration of Na2O in the water glass. When using water glass with the same SiO2 concentration, water glass D in Table 7 has a lower Na2O concentration than water glass A, so a larger amount is required to gel it. If the amount used is increased, the amount of SiO2 also increases, so the strength of the gel increases and plasticity is lost. Even if a mixture that can maintain plasticity is obtained, it will take time to obtain the required strength because there is a shortage of alkali to promote the hardening of the slag. For this reason, it can be said that water glass C is more preferable than water glass D, and water glass A is more preferable than water glass C. On the other hand, if the Na2O concentration is increased compared to water glass A, the water glass enters an unstable region and tends to crystallize at low temperatures, which is not preferable.

[0043] [Table 7]

[0044] The preferred addition ratios of the constituent materials of the thickening slag mortar of the present invention are as follows: (Water glass WG + Water W) / (Slag powder P + Filler F) = 63~250wt% Water glass WG / (slag powder P + filler F) = 3~25wt% Water W / (water glass WG + water W) = 70~100wt% Aggregate S / (Aggregate S + Slag powder P + Filler F) = 75~83wt%

[0045] Next, the apparatus used for producing the thickened slag mortar of the present invention and for the laboratory testing will be described.

[0046] The method for producing a thickened slag mortar of the present invention comprises the steps of: a slag mortar production step of adding water to the slag powder, the gypsum powder and the filler to produce slag mortar; a water glass addition and stirring process in which water glass is added to the slag mortar generated in the slag mortar generation process to instantly generate a floc-like heterogeneous gel, and then the floc-like heterogeneous gel is crushed and finely divided to promote gelation; Equipped with. The slag mortar producing step and the water glass adding and stirring step are carried out using a slurry mixer (and a mortar mixer in combination, if necessary). For the slurry mixer, a slurry mixer (product name: Fine Eco Motor) manufactured by Tokyo Glass Equipment Co., Ltd. was used to prepare the test specimen (for indoor testing). Here, a paddle-type stirring blade suitable for stirring high-viscosity materials was used for the stirring blade of the slurry mixer, and a propeller-type stirring blade was used only in Comparative Example 47 (Table 10-1) and Comparative Example 66 (Table 10-3). For the mortar mixer, a Marui mortar mixer (product number: MIC-362-1-01) was used to prepare the test specimens (for indoor testing). For practical use, for example, a mortar mixer manufactured by Kitagawa Iron Works (product name: WA series forced twin-shaft mixer) can be used. As for the agitator, for example, an agitator manufactured by Daito Kikai Co., Ltd. (product name: vibration type large agitator DAM-2000, DM-700A, SHA-1000) can be used for practical use. In addition, the shaker used in the laboratory tests was an Iwaki Sangyo Co., Ltd. shaker (product number: V-SX).

[0047] The thickening slag mortar of the present invention is useful in various construction methods for the purpose of ground improvement, etc., for example, A grout injection method in which thickening slag mortar is injected into gaps that have occurred between underground structures and the ground, or into gaps between drilled holes and the ground as a primary injection for the purpose of waterproofing soft ground or strengthening the ground. A ground improvement method that uses thickening slag mortar as a hardening material for the mid-layer mixing method, deep layer mixing method, and high-pressure jet mixing method aimed at improving soft ground. A method for manufacturing liquefied treated soil using thickening slag mortar as an additive to be mixed with construction waste soil to obtain liquefied treated soil. A liquefaction countermeasure method in which a fluid material is injected into the ground to increase the density of the surrounding ground, using thickening slag mortar as the fluid material. A pile hole filling method that uses thickening slag mortar as a backfill material for the holes that remain after underground buried piles are pulled out. It can be widely used in the following applications:

[0048] The following equipment may be used during construction: To pump the thickening slag mortar, a general-purpose concrete pump or slurry pump, for example, a concrete pump manufactured by Shintech (product number: 160-40-8) or a slurry pump manufactured by YBM (product number: SG-40VII) can be used.

[0049] Next, the method for producing the thickened slag mortar of the present invention will be specifically described. The thickening slag mortar of the present invention can be produced by the following method. Manufacturing method A of thickening slag mortar (without adding aggregate) (Fig. 2) Manufacturing method B of thickening slag mortar (with aggregate added) (Fig. 3) A thickening slag mortar is produced by adding aggregate to the slag mortar produced in the water glass adding and stirring step and stirring the mixture. Manufacturing method C of thickening slag mortar (with aggregate added) (Fig. 4) In the slag mortar production process, further aggregate is added to produce a thickened slag mortar. Manufacturing method D of thickening slag mortar (without adding aggregate) (Fig. 5) EXAMPLES

[0050] Tables 8-1 and 8-2 show the thickening slag mortars manufactured as test specimens (for indoor testing), and Table 9 shows the CO2 emission coefficients (weight of CO2 emitted when manufacturing 1 ton of each material) used in calculating the CO2 emissions in Tables 8-1 and 8-2 during the production of each material.

[0051] [Table 8-1]

[0052] [Table 8-2]

[0053] [Table 9]

[0054] In Tables 8-1 and 8-2, the amount of CO2 emissions per unit amount of thickening slag mortar was calculated by multiplying the CO2 emission coefficients shown in Table 9 during the production of each material. The thickening slag mortar of the embodiment does not use cement, so 1 m of thickening slag mortar 3 CO2 emissions per unit of production are 100 kg or less (maximum 82 kg-CO2 / m in Example 2). 3 ), which is less than one-third that of concrete, and therefore contributes to reducing the environmental impact. In particular, when the amount of Filler A added increases, the CO2 emissions turn negative, reaching a maximum of -313 kg-CO2 / m 3 This will contribute greatly to reducing the environmental impact.

[0055] Tables 10-1 to 10-3 show examples and comparative examples. The properties of the thickening slag mortars produced by manufacturing methods A to D were evaluated through various tests such as bleeding measurements, shaking tests, table flow tests, expansion and contraction rate measurements, and uniaxial compression tests to verify the effect of the thickening slag mortar of the present invention.

[0056] [Table 10-1]

[0057] [Table 10-2]

[0058] [Table 10-3]

[0059] [Breeding test] When pumping thickening slag mortar, the pump may be temporarily stopped due to moving to the next use location, changing the setup, trouble, etc. If a lot of bleeding occurs in the piping while the pump is stopped, only the bleeding water will flow when pumping again, and the quality of the material will deteriorate. The bleeding rate was calculated by placing the thickening slag mortar in a cylindrical transparent container and measuring the settling of the thickening slag mortar. In this test, the allowable bleeding limit was set at 6% after one hour.

[0060] [Shaking test] After thickening slag mortar is produced, it is temporarily stored in an agitator before being pumped. By stirring slowly with the agitator, material separation is prevented. If the thickening slag mortar has high resistance to material separation, it can maintain its pot life for a long time. In this test, a shaker was used to simulate the stirring of an agitator. After shaking at 70 spm for 3 hours, the container was removed and tilted, and the presence or absence of sedimentation of the material at the bottom was visually confirmed.

[0061] [Table flow test] (Production Method A and Production Method B) In manufacturing method A and manufacturing method B (before aggregate is added), a slurry mixer is used in the slag mortar production process and the water glass addition and mixing process. Therefore, the slurry needs to have an appropriate viscosity in each process so that it can be mixed with a slurry mixer. Furthermore, the thickening slag mortar of Production Method A must have a suitable viscosity to be pumpable, since it is pumped using a slurry pump. In this test, evaluation was performed using Table Flow Test A. It conformed to the cylinder method of JHS 313 Consistency Test Method. Tests were performed immediately, one hour, and three hours later. The cylinder dimensions were φ80mm x height 80mm. Immediately, the thickened slag mortar was measured immediately after production, and then it was continuously stirred with a shaker, and the material was taken out of the container and measured one hour and three hours later. The flow value that can be produced with a slurry mixer and pumped with a slurry pump is set at 250 mm or more. Anything less than 250 mm is deemed unacceptable. In the slag mortar production process before the addition of water glass, if a large number of lumps were formed and the powder could not be dispersed in water, it was also determined that kneading was not possible.

[0062] (Manufacturing Method B and Manufacturing Method C) The thickening slag mortars produced by manufacturing method B (after adding aggregate) and manufacturing method C are pumped using a concrete pump, so they need to have an appropriate viscosity to be pumpable. In this test, evaluation was performed using table flow test B. The static test was performed in accordance with the cylinder method of the JHS 313 consistency test method. The cylinder dimensions were φ80mm x height 80mm. The impact test was performed in accordance with the JIS R 5201 flow test. However, the cylinder of the JHS 313 consistency test method was used instead of the flow cone. The table flow values ​​at which concrete can be pumped using a concrete pump were set at 80 to 200 mm for static use and 115 mm or more for impact use. Here, when using liquefied treated soil to fill in holes left by removed piles, a static setting of 120 to 200 mm is assumed, and when used in the fluid material injection compaction method, an impact of 115 mm or more is assumed.

[0063] [Expansion / Contraction Rate] When using thickening slag mortar made by manufacturing method B or C in fluidized soil, filling pile extraction sites, or fluid material injection compaction methods, it is desirable for it to shrink little after hardening. If it shrinks too much, gaps will form between the mortar and nearby structures or the ground, which could result in a decrease in performance. In this test, it was confirmed that the expansion and contraction rate of the thickening slag mortar after hardening (after 28 days) was on the expansion side of -3%.

[0064] [Test 1] A bleeding test was conducted to evaluate the material composition (with or without gypsum addition, with or without water glass addition) and to compare manufacturing method A and manufacturing method D. Judgment criteria: Bleeding rate: within 6% (after 1 hour) The test results are shown in Table 11.

[0065] [Table 11]

[0066] The test results shown in Table 11 reveal the following: The samples without gypsum exceeded the criteria (Comparative Examples 1, 2, and 5). The sample without water glass exceeded the criterion value (Comparative Example 6). The sample without gypsum or water glass exceeded the criterion value (Comparative Example 7). When the mixing ratio was the same and the stirring speed was changed, when the stirring speed was less than 100 rpm, the flocculent non-uniform gel was not sufficiently refined and exceeded the judgment criteria, but when the stirring speed was increased to 400 to 700 rpm, bleeding became small and was within the judgment criteria (Examples 15, 18, and 19, and Comparative Examples 9 and 10). When the water glass was first diluted to a SiO2 concentration of less than 28%, a flocculent non-uniform gel was not generated instantly and exceeded the judgment criteria (Comparative Examples 11, 62, and 63).

[0067] [Test 2] After 28 days, the unconfined compressive strength was 200 kN / m 2 Tests were conducted to confirm the range of the SO3 addition rate per water glass described above. Judgment criteria: · If the shape is distorted when the summit mold is removed after 28 days, it is judged to be unconsolidated. Only specimens that could be demolded and maintained their shape were subjected to uniaxial compression tests. - Uniaxial compressive strength 200kN / m 2 The above range of SO3 addition rate per water glass was confirmed. The test results are shown in Table 12.

[0068] [Table 12]

[0069] The test results shown in Table 12 reveal the following: Compared to no-filler formulations, formulations with added fillers become more difficult to harden when the amount of SO3 per water glass exceeds a certain amount. Compared to Filler A, Filler B is less likely to harden when the amount of SO3 per water glass is large. Water glass with a large molar ratio has less Na2O, so if there is a lot of SO3 per water glass, Na2O is consumed in gelling, resulting in a shortage of Na2O required for hardening.

[0070] [Test 3] In order to confirm the preferable range of the material composition and the usable time in manufacturing method A, a bleeding test, table flow test A, a 3-hour shaking test, and a uniaxial compression test were carried out. Judgment criteria: Bleeding rate: within 6% (after 1 hour) Table flow test A: Immediately after, after 1 hour shaking, after 3 hours shaking, 250 mm End Shake for 3 hours: Remove the container and tilt it to ensure that no material has settled to the bottom. Uniaxial compression test: 0.2MN / m 2 End (28 days later) · If the shape is distorted when the summit mold is removed after 28 days, it is judged to be unconsolidated. The test results are shown in Table 13.

[0071] [Table 13]

[0072] The test results shown in Table 13 reveal the following: Comparative Example 60 lost fluidity immediately after shaking until 1 hour after shaking, so the flow test could not be performed. There wasn't. In Comparative Example 61, the fluidity was lost immediately after the application. Comparative Examples 51, 52, 57, and 58 did not caking after 28 days.

[0073] [Test 4] Tests were conducted to confirm the preferred range for adding aggregate. Judgment criteria: Table flow test B: 80 to 200 mm when left stationary Table flow value that can be pumped by concrete pump The material should not separate after the cylinder is lifted. When using liquefied treated soil to fill holes in piles, it is assumed that the soil will be left to stand for 120 to 200 mm. Table flow test B: Impact: 115mm or more Table flow value that can be pumped by concrete pump Material does not separate due to impact Expansion / contraction rate: -3% more expansion side (after 28 days) Uniaxial compression test: 0.2MN / m 2 End (28 days later) The test results are shown in Table 14 and Figures 6-1 and 6-2.

[0074] [Table 14]

[0075] The test results shown in Table 14 and Figures 6-1 and 6-2 reveal the following. Comparative Example 67 is plastic and cannot be pumped. In Comparative Example 68, the slurry separated from the gaps between the aggregates after the cylinder was lifted. The slurry separated further after impact. The separation was so great that the material could not be pumped. To obtain fluidity that allows for pumping, it is preferable that (water glass WG + water W) / (slag powder P + filler F)≧63wt% (63.7wt%) or more. (Water glass WG + water W) / (Slag powder P + filler F) is in the range of 63-250wt% (63.7-243.6wt%), and the amount of slag powder A added is 22.3kg / m 3 If it is more than this, the unconfined compressive strength is 0.2MN / m 2 More than this can be ensured. The aggregate is a material that does not affect gelation and can be added in an amount that does not impair fluidity. In addition to slag aggregate and crushed concrete sludge solid aggregate, natural aggregate, artificial lightweight aggregate, and recycled aggregate made from concrete can also be used.

[0076] Incidentally, in Comparative Examples 47, 50, and 66, the mixing was performed using a propeller-type mixing blade instead of a paddle-type mixing blade suitable for mixing high-viscosity materials, and therefore it is considered that sufficient mixing was not performed in the slag mortar generation process and the water glass addition mixing process. Therefore, a test was conducted to confirm the relationship between the stirring rotation speed and the bleeding rate when a propeller-type stirring blade and a paddle-type stirring blade were used at the blending ratio shown in Comparative Example 47. The test results are shown in Figure 7.

[0077] The test results shown in Figure 7 reveal the following: In the case of paddle-type stirring blades, which are suitable for stirring high-viscosity materials, if the stirring speed is less than 100 rpm, the flocculent non-uniform gel will not be sufficiently refined and the judgment standard value will be exceeded, but if the stirring speed is higher than that, bleeding will become smaller and fall within the judgment standard value (within 6%). In the case of a propeller-type stirring blade, if the stirring speed is less than 600 rpm, the flocculent non-uniform gel is not sufficiently refined and the judgment standard value is exceeded, but if the stirring speed is higher than that, bleeding will decrease and fall within the judgment standard value (within 6%). For the stirring blades of the slurry mixer, it is preferable to use paddle-type stirring blades, which are suitable for stirring high-viscosity materials. If a propeller-type stirring blade is used, it is necessary to ensure sufficient stirring by increasing the stirring speed, etc.

[0078] In addition, when pumping thickening slag mortar using a squeeze pump or piston pump as a concrete pump, under special conditions, such as when the pumping distance is long, when the discharge volume needs to be increased, or when the material is compressed into the ground, separation of the material may occur due to dehydration, etc., causing the pumping pressure to increase, resulting in blockage of the piping and making it impossible to pump the material. In order to improve pumpability, the following admixture addition tests were carried out. [Test 5] Table 15 shows the admixtures used.

[0079] [Table 15]

[0080] [Admixture addition test 1] In order to investigate the conditions under which the pipes would not become clogged, the possibility of pumping was confirmed when the amount of admixture A added was changed at the same mix ratio as in Example 41, and a pressurized bleeding test (JSCE-F 502, Standard Specifications for Concrete, Japan Society of Civil Engineers) was also carried out to investigate the 60-second dewatering rate and the final dewatering rate. As concrete pumps, a squeeze pump manufactured by Okasankiko Co., Ltd., model number: OPK-07M, and a piston pump manufactured by Shintech Co., Ltd., model number: SP-7E were used. Admixture A was added after stirring for 30 seconds or more after adding water glass in the water glass addition stirring process, and stirring for 90 seconds or more after adding admixture A was carried out. The test results are shown in Table 16.

[0081] [Table 16]

[0082] The test results shown in Table 16 reveal the following: Squeeze pump Conditions for pumping at a pressure of 0.5MPa: 60-second dehydration rate of 4% or less and final dehydration rate of 10% or less is around 17% or less. Piston pump Conditions for pumping at a pressure of 2MPa: Dehydration rate after 60 seconds is less than 15% and final dehydration rate is less than 30%. Conditions for pumping at a pressure of 3 MPa: 60-second dehydration rate of approximately 4% or less and final dehydration rate of approximately 17% or less. Conditions for pumping at a pressure of 5MPa: Dehydration rate after 60 seconds is less than 4% and final dehydration rate is less than 10%.

[0083] [Admixture addition test 2] In order to study the method of determining the type and amount of admixtures most suitable for thickening slag mortar, admixtures A to D were added in different amounts at the same mixing ratio as in Example 41, and a pressure bleeding test (JSCE-F 502, Standard Specifications for Concrete, Japan Society of Civil Engineers) was carried out to examine the 60-second dewatering rate and the final dewatering rate. Admixtures A to D were added after stirring for 30 seconds or more after adding water glass in the water glass addition stirring process, and admixtures A to D were added and stirred for 90 seconds or more after adding them. The test results are shown in Table 17.

[0084] [Table 17]

[0085] The test results shown in Table 17 reveal the following: The minimum amount of additive required for pumping with a squeeze pump of 0.5 MPa and a piston pump pressure of 5 MPa is as follows. However, even if the amount of additive C was increased, the 60-second dewatering rate did not decrease, and pumping at a pressure of 5 MPa was not possible. Admixture A: 0.2% in water Admixture B: 0.1% to water Admixture C: Cannot be pumped Admixture D: 0.1% to water The threshold values ​​of 0.5 MPa for the squeeze pump and 5 MPa for the piston pump pressure were set as examples of construction control values ​​for, for example, cavity filling injection work and compaction work in which concrete is pressed into the ground and compacted. However, if the above tests 1 and 2 are performed under conditions in which a pressure other than these is used as the threshold value, the minimum amount of admixture to be added that can be pumped can be obtained.

[0086] The thickening slag mortar and the manufacturing method thereof of the present invention have been described above based on the embodiments thereof. However, the present invention is not limited to the configurations described in the above embodiments, and the configurations can be appropriately changed within the scope of the invention without departing from the spirit thereof. [Industrial Applicability]

[0087] The thickening slag mortar and its manufacturing method of the present invention can provide a thickening slag mortar and its manufacturing method that can instantly thicken to reduce bleeding and material separation during pumping while maintaining a long pot life, and in particular, can provide a thickening slag mortar that can reduce CO2 emissions, and therefore can be widely used in various construction methods for the purpose of ground improvement, etc.

Claims

1. A thickening slag mortar containing at least ground blast furnace slag, gypsum powder, heavy calcium carbonate, water glass and water, but not containing cement, which is used by being pumped, and which has a CO2 emission of -350 to 100 kg per 1 m3 of thickening slag mortar, and which satisfies the following conditions (1) to (3): (1) The bleeding rate of the thickened slag mortar after one hour of production is within 6%. (2) The table flow test value of the thickened slag mortar immediately after production, after shaking for 1 hour, and after shaking for 3 hours is 250 mm or more. (3) The uniaxial compression test value of the thickened slag mortar after 28 days of production is 0.2 MN / m ２ That's all

2. The thickening slag mortar contains at least aggregate, ground granulated blast furnace slag, gypsum powder, heavy calcium carbonate, water glass, and water, but does not contain cement, and is used by being pumped, and has a CO2 emission of -350 to 100 kg per 1 m3 of the thickening slag mortar, and satisfies the following conditions (1) to (3): (1) The expansion / contraction rate after 28 days of production is on the expansion side of -3% (2) The table flow test value of the thickening slag mortar immediately after production is 80 to 200 mm when left standing and 115 mm or more when struck. (3) The uniaxial compression test value of the thickened slag mortar after 28 days of production is 0.2 MN / m ２ That's all

3. 3. The thickening slag mortar according to claim 2, wherein the aggregate is one or more selected from the group consisting of artificial aggregate, recycled aggregate, and crushed concrete sludge solid aggregate.

4. A thickening slag mortar as described in claim 1 or 2, further characterized in that it contains light calcium carbonate, and the light calcium carbonate is produced using an aqueous calcium hydroxide solution and carbon dioxide as raw materials.

5. 3. The method according to claim 1, wherein the gypsum powder is a mixture of anhydrous gypsum and dihydrate gypsum. The thickened slag mortar according to claim 1.

6. 3. The thickening slag mortar according to claim 1, wherein the molar ratio of silicic anhydride to sodium oxide in the water glass is 2.0 to 3.2, and the concentration of sodium oxide is 9 to 15% by weight.

7. The fineness of the ground granulated blast furnace slag is 3500 to 5000 cm ２ 3. The thickening slag mortar according to claim 1, wherein the viscosity of the slag mortar is 1 / g.

8. 3. The thickening slag mortar according to claim 1, further comprising an admixture for improving pumpability.

9. A method for producing a thickening slag mortar containing at least ground granulated blast furnace slag, gypsum powder, heavy calcium carbonate, water glass, and water, but not containing cement, which is used by pumping, a slurry production step of adding water to ground granulated blast furnace slag, gypsum powder, and heavy calcium carbonate to produce a slurry; a water glass addition and stirring step of adding water glass to the slurry produced in the slurry production step to produce a floc-like heterogeneous gel, and then stirring the resulting mixture to crush and finely disintegrate the floc-like heterogeneous gel, thereby accelerating gelation; A method for producing thickened slag mortar, comprising:

10. 10. The method for producing a thickened slag mortar according to claim 9, wherein aggregate is further added in the slurry producing step.

11. 10. The method for producing a thickened slag mortar according to claim 9, wherein aggregate is added to the slurry produced in the water glass adding and stirring step, and the mixture is stirred.

12. 12. The method for producing a thickened slag mortar according to claim 9, 10 or 11, further comprising adding an admixture for improving pumpability.

Images