Hydrated hardened body and method for producing the same

Abstract

A hydrated hardened body using steelmaking slag as aggregate is provided, which is capable of suppressing a decrease in fluidity. [Solution] The hydrated hardened body is produced by hardening a mixture containing aggregate containing steelmaking slag, a binder that hardens by hydration to bind the aggregate together, water, and an admixture. The admixture includes a first agent containing a lignosulfonic acid compound. The weight of the first agent is 0.4% or more and 1.5% or less of the weight of the binder.

Description

[Technical Field]

[0001] The present invention relates to a hydrated hardened body and a method for producing the same. [Background technology]

[0002] Conventionally, a hydrated hardened body is known which is produced by hardening a mixture containing aggregate containing steelmaking slag, a binder, water, and an admixture (see Patent Document 1). Such a hydrated hardened body is used as an environmentally friendly material that can be used as a substitute for concrete, for example, in roads, building foundations, etc.

[0003] When using the above-mentioned hydrated hardened body (i.e., one that contains steelmaking slag as aggregate) as a substitute for concrete material, the hydrated hardened body is required to maintain the same level of fluidity as concrete material. For general concrete materials, the upper limit of the time required from the time of production to arrival at the unloading point is set at about 90 minutes from the perspective of maintaining fluidity. Therefore, when using the above-mentioned hydrated hardened body as a substitute for concrete material, it is required to maintain appropriate fluidity for about 90 minutes from the time of production. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-31053 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the fluidity of the hydrated concrete described above is more likely to decrease than that of ordinary concrete materials. Therefore, the fluidity of the hydrated concrete decreases significantly within 90 minutes of production. Therefore, when using the hydrated concrete as a substitute for concrete materials, there are limitations to its use, such as the short distance between the production site and the unloading site.

[0006] Therefore, an object of the present invention is to provide a hydrated hardened body that uses steelmaking slag as aggregate and that can suppress a decrease in fluidity, and a method for producing the same. [Means for solving the problem]

[0007] In order to achieve the above object, the hydrated hardened body described in the specification is a hydrated hardened body obtained by hardening a mixture containing aggregate containing steelmaking slag, a binder that hardens through a hydration reaction to bind the aggregate together, water, and an admixture, wherein the admixture includes a first agent containing a lignin sulfonic acid compound, and the weight of the first agent is 0.4% or more and 1.5% or less of the total weight of the binder and the admixture (first configuration).

[0008] In the hydrated hardened body according to the first configuration, the admixture further contains a second agent containing polycarboxylic acid (second configuration).

[0009] In the hydrated hardened body according to the first or second configuration, the aggregate contains fine aggregate, and the volume of the fine aggregate contained in the aggregate is 67% or more and 70% or less of the total volume of the aggregate (third configuration).

[0010] The method for producing a hydrated hardened body described in the specification includes a first step of preparing a first mixture by mixing an admixture with water; a second step of mixing and stirring a binder that hardens through a hydration reaction to bind aggregates together, fine aggregate, and the first mixture; and a third step of mixing and stirring coarse aggregate with the binder, fine aggregate, and first mixture that have been mixed and stirred in the second step, wherein the admixture includes a first agent containing a lignin sulfonate compound, and the weight of the first agent is 0.4% or more and 1.5% or less of the total weight of the binder and admixture (fourth configuration). [Effects of the Invention]

[0011] According to the present invention, it is possible to provide a hydrated hardened body using steelmaking slag as an aggregate, which is capable of suppressing a decrease in fluidity, and a method for producing the same. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a graph showing the results of the slump test. [Figure 2] FIG. 2 is a graph showing the relationship between the admixture ratio r1 and the amount of change in slump. [Figure 3] FIG. 3 is a graph showing the test results regarding the relationship between the fine aggregate ratio r2 and viscosity. [Figure 4] FIG. 4 is a flowchart showing a method for producing the hydrated hardened body X. DETAILED DESCRIPTION OF THE INVENTION

[0013] <Regarding conventional hydrated hardened material Y containing steelmaking slag> First, the structure and problems of the conventional hydrated hardened material Y containing steelmaking slag will be explained, followed by an explanation of the hydrated hardened material X of the present invention.

[0014] Conventionally, a hydrated hardened material Y containing steelmaking slag has been used as a substitute for concrete. The hydrated hardened material Y is formed by hardening a kneading material 1y through a hydration reaction. The kneading material 1y contains an aggregate 2, a binder 3, water, and an admixture 4.

[0015] The aggregate 2 includes fine aggregate 2a and coarse aggregate 2b. The fine aggregate 2a is aggregate that passes entirely through a 10 mm mesh sieve (a metal mesh sieve with a nominal mesh size of 9.5 mm) and passes 85% or more by mass when passed through a 5 mm mesh sieve (a metal mesh sieve with a nominal mesh size of 4.75 mm). The coarse aggregate 2b is aggregate that remains 85% or more by mass when passed through a 5 mm mesh sieve.

[0016] The fine aggregate 2a contains steelmaking slag 5 and blast furnace slag 6. The coarse aggregate 2b contains steelmaking slag 7. The steelmaking slags 5 and 7 are slags generated in the steel manufacturing process. The steelmaking slags 5 and 7 can contain either converter slag or electric furnace slag, or both converter slag and electric furnace slag.

[0017] The particle size of the steelmaking slag 5 is less than 5 mm. The particle size of the steelmaking slag 7 is 5 mm or more and 25 mm or less. The blast furnace slag 6 is obtained by rapidly cooling molten slag, which is produced simultaneously with pig iron in a blast furnace, with water, air, etc., and adjusting the particle size.

[0018] The binder 3 hardens through a hydration reaction to bond the aggregates 2. The binder 3 contains ground granulated blast furnace slag 3a, ordinary Portland cement 3b, and fly ash 3c. Details of the admixture Ad1 will be described later.

[0019] <About the process that led to the invention> The time it takes for the hydrated hardened body Y to lose fluidity is shorter than that of concrete Z, which is a more common hydrated hardened body (i.e., concrete Z uses gravel instead of steelmaking slag as aggregate). First, the inventors compared the loss of fluidity between hydrated hardened body Y and concrete Z.

[0020] The inventors conducted a slump test (JIS A 1101) on each of the hydrated hardened body Y and the concrete Z. The inventors then evaluated the fluidity of each of the hydrated hardened body Y and the concrete Z by comparing the results of the slump tests.

[0021] First, an overview of the slump test will be explained. A slump test uses a slump cone, a ram, and a flat plate. The slump cone is made of metal, which is not easily corroded by cement paste and does not deform during the test. The slump cone is cylindrical, open at both ends, with the outer diameter decreasing from the bottom to the top. The inner diameter of the top end of the slump cone is 100 mm. The inner diameter of the bottom end of the slump cone is 200 mm. The height of the slump cone is 300 mm. The thickness of the slump cone is 5 mm or more. A handle is formed at approximately 2 / 3 of the height of the slump cone, protruding outward from the outer surface of the slump cone.

[0022] The tamping rod is a round metal (e.g., steel) rod with a diameter of 16 mm and a length of 500 mm or more and 600 mm or less. The tip of the tamping rod is formed in a hemispherical shape.

[0023] The flat plate is a metal plate with sufficient watertightness and rigidity. The surface of the flat plate is smooth. The area of ​​the flat plate surface is sufficiently larger than the cross-sectional area of ​​the lower end of the slump cone so that the slump test can be performed.

[0024] The person conducting the test (hereinafter simply referred to as the "tester") first places a slump cone on a flat plate. Then, the tester packs the sample to be tested into the cylindrical interior of the slump cone, dividing it into approximately three layers. At this time, each layer is leveled with a ram and then rammed 25 times evenly to ensure no bias is present. In this example, the samples used are hydrated hardened body Y and concrete Z.

[0025] Next, the tester levels the top surface of the sample packed into the slump cone so that it is aligned with the top edge of the slump cone. If, as described above, the top surface of the sample becomes lower than the top edge of the slump cone due to compaction with the tamping rod, more sample is added. The tester then lifts the slump cone. At this time, the tester lifts it vertically continuously so that the slump cone comes out of the sample within 2 to 3 seconds. The time from starting to pack the sample into the slump cone to finishing lifting the slump cone must be within 3 minutes.

[0026] The tester then measures the height of the sample from the plate at the center to the nearest 0.5 cm. The test result is recorded by subtracting the height of the slump cone (30.0 cm) from the measurement. Note that this test result is sometimes simply referred to as "slump."

[0027] Generally, the larger the slump, the higher the fluidity. For example, the slump will be larger when the amount of water is greater than the amount of binder 3, such as cement. For samples that are widely and commonly used in construction sites such as civil engineering and building construction, the appropriate slump size is approximately 12.0 cm to 20.0 cm.

[0028] Slump tests were conducted on hydrated hardened body Y and concrete Z 15 minutes after production, hydrated hardened body Y and concrete Z 30 minutes after production, and hydrated hardened body Y and concrete Z 60 minutes after production. Figure 1 is a graph showing the results of these slump tests. In Figure 1, hydrated hardened body Y is shown by a solid line, and concrete Z is shown by a dashed line.

[0029] As shown in Figure 1, 15 minutes after production, the slump of hydrated hardened product Y is greater than the slump of concrete Z. In other words, at this point, the fluidity of hydrated hardened product Y is higher than the fluidity of concrete Z. Furthermore, the slump of hydrated hardened product Y at this time exceeds the ideal range mentioned above (approximately 12.0 cm to 20.0 cm). Therefore, it can be said that the fluidity is excessive.

[0030] Thirty minutes after production, the slump of both Hydrated Hardened Material Y and Concrete Z had decreased. In other words, the fluidity of both Hydrated Hardened Material Y and Concrete Z had decreased to a certain extent. Thus, within 30 minutes of production, both Hydrated Hardened Material Y and Concrete Z experienced an initial decrease in fluidity.

[0031] 60 minutes after production, the slump of Concrete Z has not decreased from the value at 30 minutes. Therefore, even after 60 minutes, the fluidity of Concrete Z is maintained.

[0032] On the other hand, the slump of hydrated hardened product Y at this time decreased significantly after 30 minutes had passed, and was lower than the slump of concrete Z at the same time. Furthermore, the slump of hydrated hardened product Y at this time was below the ideal range (approximately 12.0 cm to 20.0 cm) mentioned above. From this, it can be said that the fluidity of hydrated hardened product Y had significantly decreased after 60 minutes had passed. From these results, the inventors discovered that the fluidity of hydrated hardened product Y decreased in a shorter time than the fluidity of concrete Z.

[0033] <Considerations on declining liquidity> When the hydrated hardened product Y is used at a construction site such as a civil engineering or building construction site, the hydrated hardened product Y before hardening is poured into a container or a frame or the like installed at the location where the hydrated hardened product Y will be installed. In order to pour the product into a desired shape and location, it is necessary to maintain the fluidity of the hydrated hardened product Y at a suitable level from the time of production until the time of pouring. In the case of concrete Z, the upper limit of the time required from the time of production until arrival at the site (i.e., immediately before pouring) is set at approximately 90 minutes. In other words, concrete Z is designed to maintain a suitable fluidity for at least approximately 90 minutes from the time of production.

[0034] On the other hand, as mentioned above, the results of the slump test showed that the fluidity of the hydrated hardened product Y fell below the ideal range 60 minutes after production. When the fluidity falls below the ideal range, it becomes difficult to pour the hydrated hardened product Y into a container, etc., and imperfect filling is likely to occur inside the container, etc. If the hydrated hardened product Y hardens while being imperfectly filled, the durability of the structure using the hydrated hardened product Y may be reduced.

[0035] The inventors therefore investigated a method for optimally maintaining the fluidity of a hydrated hardened body containing steelmaking slag as an aggregate, such as the above-mentioned hydrated hardened body Y. As described above, hydrated hardened body Y is produced by containing aggregate 2, binder 3 that binds the aggregate 2 together, water, and admixture 4. Here, the inventors investigated the fluidity of the hydrated hardened body, focusing particularly on the type and amount of chemical agent used as admixture 4.

[0036] Generally, two chemicals, the aforementioned admixture Ad1 and admixture Ad2, are used as the admixture 4 for the hydrated hardened body. Admixture Ad1 is used to adjust the initial fluidity of the kneaded mixture. On the other hand, admixture Ad2 is used to maintain the initial fluidity of the kneaded mixture. Therefore, the inventors focused on admixture Ad2.

[0037] In general, in the case of hydrated hardened bodies containing a large amount of ground granulated blast furnace slag, it has been confirmed that the use of an admixture containing a chemical agent (= admixture) containing a lignosulfonic acid compound is effective in maintaining fluidity. Therefore, the inventors selected a type of admixture Ad2 containing a lignosulfonic acid compound. The inventors then conducted extensive research into the relationship between the amount of admixture Ad2 and the fluidity of the hydrated hardened body.

[0038] <Considerations on the amount of admixture Ad2> Figure 2 is a graph showing the relationship between the admixture ratio r1 and slump change. The admixture ratio r1 is the ratio of the weight of admixture Ad2 to the weight of binder 3. The slump change is the change in the slump of the hydrated hardened body 90 minutes after production compared to the slump of the hydrated hardened body at the time of production. The slump change is calculated by subtracting the slump of the hydrated hardened body at the time of production from the slump of the hydrated hardened body 90 minutes after production. In Figure 2, a slump change between -5.0 cm and 0 cm is considered to have maintained good fluidity.

[0039] As shown in Figure 2, when the admixture ratio r1 is less than 0.4%, the slump change is less than -5.0 cm. Also, as shown in Figure 2, when the admixture ratio r1 is 2%, the slump change exceeds 0 cm.

[0040] On the other hand, when the admixture ratio r1 is in the range of 0.4% to 1.5%, the slump change is in the range of −5.0 cm to 0 cm.

[0041] From the above, the inventors have discovered that the fluidity of the hydrated hardened body can be maintained for 90 minutes when the admixture ratio r1 is 0.4% or more and 1.5% or less. This discovery led the inventors to conceive of the hydrated hardened body X of the present invention. The hydrated hardened body X of the present invention is as follows:

[0042] <Hydrated hardened body X according to an embodiment of the present invention> The hydrated hardened body X according to the present invention is formed by hardening the kneading material 1x through a hydration reaction. The kneading material 1x contains the aggregate 2, binder 3, water, and admixture Ad1, which are the same as those described above. In addition, the kneading material 1x contains admixture Ad2.

[0043] In the hydrated hardened body X according to this embodiment, the weight of the admixture Ad2 contained in the kneading material 1x is 0.4% or more and 1.5% or less relative to the weight of the binder 3.

[0044] <Considerations on viscosity> As mentioned above, it was found that fluidity could be maintained for 90 minutes by appropriately adjusting the type of admixture Ad2 and the admixture ratio r1. However, the ease of use of hydrated hardened body X at construction sites such as civil engineering and building construction sites does not depend solely on fluidity. Ease of use can also depend on viscosity, for example. If the viscosity is high, problems such as the time required for construction at the construction site can arise. For this reason, it is desirable for hydrated hardened body X to have a moderate viscosity.

[0045] Viscosity will be explained using specific examples as follows. The longer it takes for the slump to reach -5.0 cm in a slump test, the less likely the mound will crumble after the slump cone is pulled out. In other words, the higher the viscosity. Conversely, the shorter it takes for the slump to reach -5.0 cm in a slump test, the more likely the mound will crumble after the slump cone is pulled out. In other words, the lower the viscosity.

[0046] Generally, for a general-purpose hydrated hardened body, if the time it takes for the slump to reach -5.0 cm is 1 to 2 seconds, it can be said to have an appropriate viscosity (i.e., a viscosity that is easy to use). Therefore, the inventors have conducted extensive research on hydrated hardened body X, not only in terms of fluidity but also in terms of viscosity.

[0047] Here, viscosity is greatly affected by the amount of admixture Ad1 added and the fine aggregate ratio r2. Generally, the total amount of admixture Ad1 and admixture Ad2 added is about 0.5 to several percent relative to the weight of binder 3. The admixture ratio r1 of hydrated hardened body X is set to 0.4 to 1.5%. The weight (addition amount) of admixture Ad1 in hydrated hardened body X is set to 0 to 0.8% relative to the weight of binder 3.

[0048] The inventors have focused on the influence of the fine aggregate ratio r2 on viscosity. The fine aggregate ratio r2 is the ratio of the volume of fine aggregate 2a to the volume of aggregate 2. The inventors have conducted tests and evaluated the relationship between the fine aggregate ratio r2 and viscosity. Figure 3 is a graph showing the test results.

[0049] In this test, the admixture ratio r1 was set to 0.4%. A chemical agent whose main component is polycarboxylic acid was selected as the admixture Ad1. The amount of admixture Ad1 added was set so that the weight of admixture Ad1 was 0.8% of the weight of binder 3. Chemical agents whose main component is polycarboxylic acid are commonly used as admixture Ad1.

[0050] In this test, the fine aggregate ratio r2 was varied. As in the slump test described above, the slump cone was removed, and the time it took for the slump of the sample (here, hydrated hardened body X) to reach -5.0 cm (hereinafter simply referred to as the "slump time") was measured.

[0051] As a result, as shown in Figure 3, it was found that when the fine aggregate ratio r2 is less than 67%, the slump time is 10 seconds. On the other hand, when the fine aggregate ratio r2 is 67% to 70%, the slump time is 1 to 2 seconds. As mentioned above, if the time it takes for the slump to reach -5.0 cm is 1 to 2 seconds, it can be said to be an appropriate viscosity for a general-purpose hydrated hardened body.

[0052] If the fine aggregate ratio r2 exceeds 70%, the amount of bleeding water seeping out from the hydrated hardened body X before hardening will be significantly increased, which may result in poor quality (e.g., due to subsidence of the surface of the hydrated hardened body X). For this reason, it is preferable that the upper limit of the fine aggregate ratio r2 be set to 70%.

[0053] From the above, the inventors have found that when the fine aggregate ratio r2 of the hydrated hardened body X is set to 67% or more and less than 70%, the hydrated hardened body X has a viscosity suitable for general use. Based on this finding, the fine aggregate ratio r2 of the hydrated hardened body X of the present invention is set to 67% or more and less than 70%.

[0054] <About the manufacturing method of hydrated hardened body X> Next, a method for producing the hydrated hardened material X according to an embodiment of the present invention will be described. Fig. 4 is a flowchart showing a method for producing the hydrated hardened material X. As shown in Fig. 4, the method for producing the hydrated hardened material X includes a measuring step St1 (first step), a pre-mixing step St2 (first step), a first stirring step St3 (second step), and a second stirring step St4 (third step).

[0055] In the measuring step St1, the weight of the admixture, including the admixture 4 and water, is measured. More specifically, in the measuring step St1, the admixture Ad1, the admixture Ad2, and the water are individually measured. Next, in the pre-mixing step St2, the measured admixture Ad1, the admixture Ad2, and the water are mixed. This mixture of the admixture Ad1, the admixture Ad2, and the water is referred to herein as the first mixture.

[0056] Next, the first mixing step St3 will be described. In the first mixing step St3, the first mixture, fine aggregate 2a, and binder 3 are first charged into a mixer (step St31). Next, the first mixture, fine aggregate 2a, and binder 3 are mixed and stirred in the mixer for 30 seconds to form a uniform paste, thereby producing a second mixture (step St32). After that, coarse aggregate 2b is charged into the mixer (step St33).

[0057] After step St33, in the second mixing step St4, the second mixture is mixed and stirred for 90 seconds using a mixer so that the coarse aggregate is uniformly distributed in the second mixture. In this way, through the measuring step St1 to the second mixing step St4, a hydrated hardened body X is produced.

[0058] Next, the hydrated hardened material X of the present invention will be described in more detail using examples. [Example]

[0059] Tests were conducted on the hydrated hardened materials X1 and X2 according to the present invention and the hydrated hardened materials A1 and A2 as reference examples to evaluate their fluidity and viscosity. In the tests, the aforementioned slump change and slump time were measured. Specific test conditions were as follows:

[0060] The tests were conducted in an indoor testing room at a temperature of approximately 20°C. Four types of hydrated hardened bodies (hydrated hardened bodies X1, X2, A1, and A2) were prepared as samples, with varying contents of admixtures Ad1 and Ad2. The contents of each material in the kneaded mixtures of hydrated hardened bodies X1, X2, A1, and A2 are shown in Table 1.

[0061] [Table 1]

[0062] A small oscillating mixer (known as an omnimixer) was used to mix each sample. The mixing procedure was as follows: first, water, binder 3, and fine aggregate 2a were added and mixed for 30 seconds, then coarse aggregate 2b was added and mixed for 90 seconds (see Figure 4). Admixture 4 was mixed with water in advance. The amount of admixture Ad1 was adjusted according to the amount of admixture Ad2 so that the fluidity of each of the hydrated hardened bodies X1, X2, A1, and A2 during production would be approximately the same.

[0063] The tests were conducted separately as a fluidity evaluation test to check fluidity and a viscosity evaluation test to check viscosity. The fluidity evaluation test was the same as the test to measure the slump change amount described above. The viscosity evaluation test was the same as the test to measure the slump time described above. For the fluidity evaluation test, hydrated hardened materials X1, X2, A1, and A2 were placed in containers, the containers were covered, and stored, and the materials were mixed with a scoop every 10 minutes from the time of production until the test was conducted.

[0064] In the fluidity evaluation test, as described above, if the slump change is between -5.0 cm and 0 cm, it is evaluated that fluidity is maintained appropriately. In the viscosity evaluation test, as described above, if the slump time is within 2 seconds, it is evaluated that viscosity is appropriate.

[0065] Regarding viscosity, even if the viscosity has a slump time of more than 2 seconds, it may not be a problem depending on the intended use, construction method, and construction site environment of the hydrated hardened body. Hydrated hardened bodies with a slump time of 2 seconds or less can be evaluated as suitable for general use, as they are easily adaptable to a variety of intended uses, construction methods, and construction site environments.

[0066] As shown in Table 1, hydrated hardened products X1 and X2 have an admixture ratio r1 within the range of 0.4 to 1.5%, and can be considered examples of hydrated hardened product X. On the other hand, hydrated hardened products A1 and A2 have an admixture ratio r1 outside the range of 0.4 to 1.5%, and are therefore treated as reference examples that are not included in the hydrated hardened product X of the present invention.

[0067] The results of the fluidity evaluation test and viscosity evaluation test are shown in Table 2.

[0068] [Table 2]

[0069] First, the results of the fluidity evaluation test will be explained. As shown in Table 2, the slump change of hydrated hardened bodies X1 and X2 was within the range of -5.0 cm to 0 cm. This means that hydrated hardened bodies X1 and X2 maintained good fluidity.

[0070] On the other hand, the slump changes of the hydrated hardened bodies A1 and A2 are outside the range of -5.0 cm to 0 cm, which indicates that the fluidity of the hydrated hardened bodies A1 and A2 is not adequately maintained.

[0071] Next, the results of the viscosity evaluation test will be explained. As mentioned above, it was confirmed that a fine aggregate ratio r2 of 67 to 70% results in an appropriate viscosity. As shown in Table 1, the fine aggregate ratio r2 of both hydrated hardened bodies X1 and A1 is in the range of 67 to 70%. As shown in Table 2, the slump change of hydrated hardened bodies X1 and A1 is in the range of -5.0 cm to 0 cm. In other words, hydrated hardened bodies X1 and A1 have an appropriate viscosity for general-purpose use.

[0072] On the other hand, as shown in Table 1, the fine aggregate ratio r2 of both Hydrated Hardened Materials X2 and A2 is outside the range of 67 to 70%. And as shown in Table 2, the slump change of Hydrated Hardened Materials X2 and A2 is outside the range of -5.0 cm to 0 cm. In other words, Hydrated Hardened Materials X2 and A2 do not have the viscosity suitable for general-purpose use.

[0073] As described above, the results of the fluidity evaluation test showed that when the admixture ratio r1 is in the range of 0.4 to 1.5%, the fluidity of hydrated hardened body X is maintained appropriately. Furthermore, the results of the viscosity evaluation test showed that when the fine aggregate ratio r2 is in the range of 67 to 70%, the viscosity of hydrated hardened body X is suitable for use as a general-purpose hydrated hardened body.

[0074] <Modification> The present invention is not limited to the above embodiment, and various modifications are possible within the scope of the present invention. For example, although a chemical agent containing polycarboxylic acid as the main component is selected as the admixture Ad1, other chemical agents may also be used. Furthermore, the admixture 4 does not necessarily have to contain the admixture Ad1.

[0075] Furthermore, the admixture Ad2 may contain other ingredients as long as it is an agent containing a lignosulfonic acid compound. [Explanation of symbols]

[0076] 1x Mixing material 1y Mixing material 2. Aggregate 2a Fine aggregate 2b Coarse aggregate 3 Binding material 3a Ground granulated blast furnace slag 3b Ordinary Portland cement 3c Fly ash 4 Admixtures 5, 7 Steelmaking slag 6. Blast furnace slag A1, A2 Hydrated hardened product Ad1 Admixture (Second Agent) Ad2 Admixture (first agent) St1 Measurement Engineering (Project 1) St2 Pre-construction Mixed Engineering (Project 1) St3, First Mixing Works (Second Works) St4, Second Mixing Works (Third Works) X Water and hardened body X1, X2 Water and Hardened Body Y Water and hardened body Z コンクリート r1 mixing ratio r2 Fine aggregate ratio

Claims

1. A hydrated hardened body obtained by hardening a kneaded mixture containing aggregates containing steelmaking slag, a binder that hardens by a hydration reaction to bind the aggregates together, water, and an admixture, The admixture includes a first agent containing a lignosulfonic acid compound, A hydrated hardened body in which the weight of the first agent is 0.4% or more and 1.5% or less of the weight of the binder.

2. The hydrated hardened body according to claim 1 , wherein the admixture further comprises a second agent containing a polycarboxylic acid.

3. The aggregate includes fine aggregate, 3. The hydrated hardened body according to claim 1, wherein the volume of the fine aggregate contained in the aggregate is 67% or more and 70% or less of the volume of the entire aggregate.

4. A first step of preparing a first mixture by mixing an admixture and water; a second step of mixing and stirring a binder that hardens through a hydration reaction to bind the aggregates together, fine aggregate, and the first mixture; a third step of mixing and stirring the binder, the fine aggregate, and the first mixture mixed and stirred in the second step with coarse aggregate; Including, The admixture includes a first agent containing a lignosulfonic acid compound, A method for producing a hydrated hardened body, wherein the weight of the first agent is 0.4% or more and 1.5% or less of the total weight of the binder and the admixture.

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