TWI543957B - Method for manufacturing hydrated solidified body and hydrated solidified body - Google Patents

Description

Method for producing hydrated solidified body and hydrated solidified body

The present invention relates to a method for producing a hydrated solidified body produced by kneading powdered steel slag with a substance containing SiO ₂ by water, and a hydrated solidified body.

The slag produced in the steel making step (hereinafter abbreviated as steel slag) has a high alkalinity and contains a large amount of free CaO. Therefore, since the steel slag is easily expanded by the hydration reaction, it is not suitable for use as a civil engineering or construction material like blast furnace slag, and it is troublesome to handle it. Therefore, in recent years, in order to break this situation, a technique of actively and effectively utilizing steel slag has been proposed. Specifically, Patent Document 1 describes a method in which an aggregate containing steel slag and a substance containing 50% or more of a potentially hydraulic cerium oxide and a pozzolanic reactivity are contained. One or two types of cerium oxide materials which are solidified by a hydration reaction are mixed to produce a hydrated solidified body. Further, Patent Document 2 discloses that all of the bonding material, the fine aggregate, and the coarse aggregate are made into pulverized and crushed steel slag, and steel slag mixed with blast furnace slag and steel slag is used as a combination. A slag block (hydrated solidified body) made of material.

[Prior Art Literature]

[Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. Hei 10-152364

[Patent Document 2] Japanese Patent Laid-Open No. Hei 2-233539

[Patent Document 3] Japanese Patent No. 3654122

[Patent Document 4] Japanese Patent No. 4438307

However, the inventors of the present invention have attempted to produce a hydrated solidified body using steel slag as a raw material by using the production methods described in Patent Document 1 and Patent Document 2, and as a result, the following problems have been clarified.

In other words, in the production method described in Patent Document 1, when the converter slag is used as the steel slag, the hydrated solidified body is disintegrated when it is hardened in water at 20 ° C, and it is unsatisfactory. Therefore, the inventors of the present invention investigated the cause in detail, and as a result, it was found that the CaO component or the MgO component added during the steel making process does not melt in the slag and remains, or precipitates upon cooling, and hydrates and solidifies. Body disintegration. The reason for this is that the CaO component or the MgO component existing in the form of CaO or MgO in the slag is hardened in water to hydrate and swell. On the other hand, as in the production method described in Patent Document 2, when the binder is contained and the main body is made of steel slag, the compressive strength of the hydrated solidified body is insufficient in almost all cases, and it is difficult to exhibit stable strength. Therefore, the hydrated solidified body produced by the production method described in Patent Document 2 cannot be used as an alternative to cement-concrete.

In addition, in order to solve such a problem, it is proposed to limit the type of steel slag and to use a material mainly composed of blast furnace slag micropowder as a binder material. The method for producing a cured body is practical. In the above-described production method, the molten iron pretreatment slag is used as the steelmaking slag, and the ratio of the particles having a particle diameter of 1.18 mm or less is set to 15% by mass of all the amounts other than water. ~55 mass% range. Further, Patent Document 4 describes a technique for producing a stable hydrated solidified body by limiting the pulverization rate of the steel slag.

Therefore, the inventors of the present invention have produced a hydrated solidified body based on these findings, and as a result, it has been confirmed that characteristics excellent in strength or volume stability can be obtained. When the hydrated solidified body thus obtained was exposed to various environments and subjected to follow-up investigation, it was found that there was no particular problem when it was used by being immersed in sea or river. However, it can be seen that in the case of exposure to the tidal zone on the coast or exposure to rain or sunshine on land, there have been few cases of large-scale cracking or breakage after many years. On the other hand, in the range in which the core or the like was removed from the residual portion and the static compressive strength was evaluated, no significant decrease in strength was observed, and the cause of cracking or the like was not clear.

In order to more effectively utilize industrial by-products represented by steel slag, the hydrated solidified body is not limited to use in sea or water, and is indispensable for use in various applications such as earth-water substitutes in the ebb tide block in the coastal area or in the terrestrial area. . In this case, the hydrated solidified body is used for a long period of time in various natural environments such as air temperature and sunlight, and long-term durability is also an essential characteristic. Previously, a great deal of research has been conducted on the durability due to the expansion stability of steel slag. However, according to past findings, even in the case of using a volume-stable steel slag, although there is no problem in a small size, there is a possibility that durability is deteriorated when a large product is exposed to a certain condition. Sex, but ask for countermeasures.

The present invention has been made in view of the above problems, and an object of the invention is to provide a method for producing a hydrated solidified body which can obtain a hydrated solidified body having high durability in an environment in which stress is repeatedly applied. Further, another object of the present invention is to provide a hydrated solidified body which has high durability in an environment in which stress is repeatedly applied.

In the powdered steel slag, the powdering rate is low, and it can be said that it has a function similar to that of the aggregate in the concrete, and contributes to the reaction of a part of the bonding material. The particle size of the steel slag is not particularly limited except for 25 mm or less ("Steel Slag Hydrate Solidification Technical Manual" (refer to the Coastal Technology Research Center (the Corporation)). In addition, as described above, Patent Document 3 describes that the ratio of the particles of 1.18 mm or less is in the range of 15% by mass to 55% by mass based on the total amount of the components other than water.

The inventors of the present invention and the steel slag satisfying the above conditions are kneaded under various mixing conditions, and the hydrated solidified body is subjected to exposure evaluation. As a result, it is understood that there is no problem in forming a riprap or a small-sized block. However, it can be seen that there is a case where cracks occur when the weight is more than 2.5 tons, or when it is placed in an environment such as a hot environment or a dry-wet cycle.

Further, the inventors of the present invention conducted intensive studies on the cause, and as a result, found that the influence of the particle size of the steel slag is extremely large. The inventors of the present invention have found that it is particularly important to determine not only the proportion of particles having a fine particle size of 1.18 mm or less but also particles having a large particle size in an appropriate ratio. Bright.

In the method for producing a hydrated solidified body of the present invention, a hydrated solidified body is produced by kneading a powdery steel slag with a substance containing SiO ₂ with water, and is characterized in that a temperature at 80 ° C is used as the steel slag. Steel slag having a pulverization ratio of 2.5% by mass or less and a coarse particle ratio of 4.5 or more after immersion in water for 10 days, and blast furnace slag fine powder or blast furnace slag fine powder and fly ash are used as the SiO ₂ -containing substance. (fly ash).

In the method for producing a hydrated solidified body of the present invention, the steel slag having a ratio of particles having a particle diameter of 0.5 mm or less in a range of 10% by mass or more is used as the steel slag.

The method for producing a hydrated solidified body of the present invention is the above invention, wherein the alkali metal and/or alkaline earth is added in an amount of 0.2% by mass to 20% by mass based on the total content of the blast furnace slag fine powder and the fly ash. One or two or more kinds of metal oxides, hydroxides, sulfates, and chlorides.

The method for producing a hydrated solidified body of the present invention is the above-mentioned invention, wherein 200% by mass of the total content of the blast furnace slag fine powder and the fly ash is added as an upper limit and is selected from ordinary Portland cement and fly ash. One or more types of cement and composite cement.

The method for producing a hydrated solidified body of the present invention is the above invention, wherein the total amount of oxides, hydroxides, sulfates, and chlorides relative to the blast furnace slag fine powder, fly ash, and alkali metal and/or alkaline earth metal The content is in the range of 0.1% by mass to 2.0% by mass, and naphthalenesulfonic acid and/or polycarboxylic acid is added.

The hydrated solidified body of the present invention is produced by the method for producing a hydrated solidified body of the present invention.

The hydrated solidified body of the present invention has the above-described invention, and the fatigue strength of 1 million times after curing exceeds 50% of the static fatigue strength.

The hydrated solidified body of the present invention is as described above, and is used for an intertidal zone, a spatter zone, or a land zone along the sea.

The hydrated solidified body of the present invention is as described above, and is used for a member having a weight of 1 ton or more.

According to the present invention, it is possible to provide a hydrated solidified body which also has high durability in an environment in which stress is repeatedly applied.

FIG. 1 is a view showing an example of the relationship between the FM value of the steel slag and the number of times of repeated load up to the breakage.

2 is a view showing an example of the relationship between the slag diameter of 10% on the fine particle side and the slump of the kneaded material.

The hydrated solidified body produced by using the steel slag is produced by using a material which is low in expansion stability as steel slag as a material corresponding to the aggregate, and then adding a bonding material and water to knead it. In the present invention, in order to obtain high durability, the following conditions (1) and (2) are satisfied as the steel slag, including the above. Further, in the present invention, as the bonding material, blast furnace slag fine powder, blast furnace slag fine powder, and SiO ₂ containing materials such as fly ash are used.

(1) The content of a mineral having swelling such as CaO or MgO is low, and the powdering rate is low.

(2) The coarse grain rate (FM value) is 4.5 or more

The molten steel slag may be exemplified by a molten iron pretreatment slag (dephosphorization slag or slag slag, etc.), a converter decarburization slag, an electric furnace slag, or the like, and one or more of these may be used. The steel slag is preferably a particle size having a maximum particle diameter of 25 mm or less.

In the steelmaking slag, CaO or MgO is mixed in the refining process. Most of CaO or MgO is a composite oxide with other elements such as SiO ₂ or FeO, but a part thereof exists in a state of free CaO or free MgO. When free CaO or free MgO remains directly in a large amount, it reacts with water to become Ca(OH) ₂ or Mg(OH) ₂ and swells. The mineral phases can be suppressed to a low level by controlling the composition or cooling of the steel slag.

The hydration reaction is promoted by long-term weathering or steam aging of the steel slag in an outdoor yard, and before the hydrated solid body is used, the free CaO or the free MgO is previously converted into Ca ( OH) ₂ or Mg(OH) ₂ . Thereby, there is no problem in using the steel slag as a material corresponding to the aggregate. On the other hand, when the steel slag to be used is powdered at a temperature of 80 ° C for 10 days, the ratio of the powdery slag is 2.5% by mass or less, and the strength of the hydrated solidified body is not affected. Therefore, even if such a steel slag is used for a small-sized product having little change due to stress or the like, it does not affect the damage of the product or the like.

According to the previous findings, it is found that the steel slag only defines the ratio of particles having a particle diameter of 1.18 mm or less to produce a large block and is exposed to land or intertidal zone, and as a result, it is observed that if it is exposed for a long period of time according to the situation, large-scale occurrence occurs. damaged. The use of a large shape is necessary to be large, in other words, it is not preferable that the weight of the monomer is light due to breakage during use. Therefore, high durability is required when compared with the use of a stone substitute.

According to the raw material blending or the material properties of the breaker caused by such a large shape, the conditions for not causing the damage are investigated, and as a result, it is understood that not only the ratio of the fine particle size of the steel slag used is large, but also The overall particle size is balanced and the durability changes greatly. Unlike the natural stone material, the steel slag is broken by solidification of the melt as a by-product. Therefore, it is understood that the particle size varies depending on the subsequent use, and it is important to crush and apply it under optimum conditions.

Therefore, when a reverse load corresponding to a strength of 50% when the static breaking strength of each condition is set to 100% is applied, it is investigated that damage is caused when a load is applied a few times. As a result, it is understood that the relationship between the aggregates is evaluated by the FM (Fineness Modulus) value which is an index of the particle size. That is, the particle size distribution is determined by screening each sieve having a mesh opening of 37.5 mm, 19.0 mm, 9.50 mm, 4.75 mm, 2.36 mm, 1.18 mm, 0.60 mm, 0.30 mm, and 0.15 mm, and the quality remaining in the sieve is determined. The percentage is summed and divided by 100 as the FM value, and the number of damages is investigated. As a result, as shown in Fig. 1, the smaller the FM value, the more easily the damage is caused. When the FM value is 4.5 or more, the fatigue durability of more than 1 million times can be secured, and the FM value exceeds 4.8. When you can ensure 200 More than 10,000 times of fatigue durability. In other words, the inventors of the present invention have found that when the FM value of the steelmaking slag is 4.5 or more, more preferably 4.8 or more, a hydrated solidified body having high durability can be obtained.

Further, in the present specification, the term "large-sized member" means a member having a monomer weight of more than 1 ton. For components lighter than 1 ton, even if the FM value is lower than 4.5, stable performance can be obtained substantially. However, when a load is applied to a part of the structure or the variation of the wet and dry is large, it is preferable to use an FM value of 4.5 or more for a member having a light weight of 1 ton.

On the other hand, even if the FM value is increased, the range of the construction method and the like is naturally limited from the viewpoint of fluidity, and the FM value is preferably 6.4 or less, more preferably 6.0 or less. For example, when only steel slag of about 5 mm is used, the fluidity of the kneaded material is lowered and the workability is deteriorated. Therefore, the inventors of the present invention further studied the conditions required to maintain the workability. As a result, the inventors of the present invention found that the proportion of the fine portion of the steel slag has a strong influence on the kneading and construction.

Accordingly, the diameter of 10% of the slag mass is focused on the fine-grained steel slag side (D _10), by the same formulation (water 198kg / m ^3, the bonding material is 527kg / m ^3, a residual portion is set Steel slag) investigates the twist of the kneaded material. When the results are shown as in FIG. 2, when D ₁₀ is less than 0.5mm, in other words, the ratio of particles below 0.5mm is more than 10 mass%, good workability can be maintained. On the other hand, when D ₁₀ exceeds 0.5 mm, the upper part of the test body does not sink and disintegrates laterally at the time of removing the slump cone. Therefore, the evaluation of the twist is 0 cm.

In the present invention in which the entire particle size is increased in the FM value, that is, the coarse particles are increased to ensure the durability, the steel slag having an adaptive particle size distribution having a ratio of particles containing 0.5% by mass or more and 0.5 mm or less is further used. It ensures high durability and good mixing and workability.

By using the above slag, a solidified body using steel slag as an aggregate and having high durability can be obtained. Due to its high durability, it can be used not only for small applications, but also for large components such as weights exceeding 1 ton. In particular, it can be used as a substitute for natural stone, etc., or as a concrete block represented by a low-temperature block, in the intertidal zone or the spatter zone of the coast where the wet and dry reappears, and the land on which rain and sunshine reappear. The way to use.

The present invention ensures long-term durability by using the steel slag as described above. In addition, one or two or more kinds of oxides, hydroxides, sulfates, and chlorides selected from the group consisting of alkali metals and/or alkaline earth metals may be added in an amount of 0.2% by mass or more. Thereby, the initial strength of the hydrated solidified body can be stably exhibited, the curing can be accelerated, the time required for the hardening can be shortened, and the quality of the construction management can be improved. The upper limit of the amount of addition is not particularly limited, and since the effect is saturated even when the amount is more than 20% by mass, the upper limit of the amount of addition is 20% by mass.

Ordinary Portland cement, fly ash cement, and composite cement can also be used as an auxiliary material for the substance containing SiO ₂ . For example, a production site suitable for a blast furnace slag fine powder is separated from a manufacturing site of a solidified body, and a large amount of blast furnace slag fine powder is economically unfavorable, or it is difficult to obtain an alkali metal and/or an alkaline earth metal. The case of oxides, hydroxides, sulfates, and chlorides. At this time, since the particle size configuration of the fine powder portion is changed, and the steel slag having a large specific gravity is easily separated, the content of these is set to an upper limit of 200% by mass based on the total content of the blast furnace slag fine powder and fly ash.

When naphthalenesulfonic acid and/or a polycarboxylic acid is added, the kneadability at the time of kneading a raw material and water is improved. Therefore, the amount of water required for kneading can be reduced, and as a result, a higher strength hydrated solidified body can be obtained. When the amount of addition is less than 0.1% by mass based on the total content of oxides, hydroxides, sulfates, and chlorides of the blast furnace slag fine powder, fly ash, and alkali metal and/or alkaline earth metal, the effect is lacking. On the other hand, since the addition is more than 2.0% by mass, the effect is saturated, so the amount of addition is limited to the range of 0.1% by mass to 2.0% by mass.

[Examples]

In the present embodiment, a hydrated solidified body was produced using a granular granular steel slag having a particle size adjusted. As the powdery granular steel slag, the molten iron pretreatment slag which is produced when the blast furnace molten iron from the blast furnace is subjected to dephosphorization treatment is used. Further, as the bonding material, blast furnace pulverized slag fine powder and fly ash are used, and as the alkaline stimulating material, ordinary Portland cement is used. The particle size, FM value, and D ₁₀ of the steel slag used for the test were selected as the conditions and comparative conditions of the present invention. The particle size, FM value, and D ₁₀ at this time are shown in Table 1.

The blender was used to mix the powdered granular steel slag, the bonding material, the alkaline stimulating material, and water using the mixer shown in Table 2. In order to evaluate the workability, the kneading degree of the kneaded product was measured according to the twist test method of Japanese Industrial Standard JIS A 1101, and then molded into a mold of 10 cm × 10 cm × 40 cm. After 2 days, the molded product was deframed, and after hardening in water at 20 ° C for 28 days, a bending fatigue test was performed. The bending fatigue test is based on the fracture stress obtained by the bending strength test method of Japanese Industrial Standard JIS A 1106, and the 50% stress is the upper limit stress and the 5% stress is the lower limit stress. The frequency is 7 Hz. Perform a repetitive load. The number of times until the number of times exceeds 1 × 10 ⁶ is judged as ○, and the number of times less than 1 × 10 ⁶ is judged as ×. The results of the twist and durability are shown together in Table 1.

As shown in Table 1, when the coarse grain ratio of the steel slag is within the range of the present invention, high durability can be obtained. On the other hand, in the case where the coarse grain rate of the steel slag was low, it was confirmed that the durability could not be sufficiently ensured. In addition, under the condition of D ₁₀ large, although the durability can be ensured, if the twist cone is pulled in a fresh state, the upper portion of the test body does not sink and collapses around, and the flaw cannot be measured. degree. When D _{10 is} large, it can be formed by a shape or a molding method. However, in order to form a cured product having good workability or processing, it is preferable to set D ₁₀ to be 0.5 or less. As described above, by setting it as the range of the present invention, it is possible to stably exhibit high durability which has not been previously obtained.

[Industrial availability]

As described above, the present invention can be applied to a process of producing a hydrated solidified body by kneading a powdery steel slag with a substance containing SiO ₂ with water.

Claims (9)

A method for producing a hydrated solidified body, which is obtained by kneading a powdery steel slag and a substance containing SiO ₂ with water to produce a hydrated solidified body, and is characterized in that the steel slag is used at 80 ° C. a slag having a pulverization rate of 2.5% by mass or less and a coarse particle ratio of 4.5 or more after immersion in warm water for 10 days; and a blast furnace slag fine powder or blast furnace slag fine powder and fly as the SiO ₂ -containing substance gray. The method for producing a hydrated solidified body according to the first aspect of the invention, wherein the steel slag having a ratio of particles having a particle diameter of 0.5 mm or less is 10% by mass or more. The method for producing a hydrated solidified body according to the first aspect or the second aspect of the invention, wherein the total content of the blast furnace slag fine powder and the fly ash is added in a range of 0.2% by mass to 20% by mass. One or two or more kinds selected from the group consisting of oxides, hydroxides, sulfates, and chlorides of alkali metals and/or alkaline earth metals. The method for producing a hydrated solidified body according to the first aspect or the second aspect of the invention, wherein the total content of the blast furnace slag fine powder and the fly ash is 200% by mass as an upper limit and is selected from ordinary waves. One or more of Portland cement, fly ash cement, and composite cement. The method for producing a hydrated solidified body according to the first or second aspect of the invention, wherein the blast furnace slag fine powder, the fly ash, and the alkali metal and/or alkaline earth metal oxide or hydrogen The total content of the oxide, the sulfate, and the chloride is added to the naphthalenesulfonic acid and/or the polycarboxylate in the range of 0.1% by mass to 2.0% by mass. acid. A hydrated solidified body produced by the method for producing a hydrated solidified body according to any one of the first to fifth aspects of the invention. The hydrated solidified body described in claim 6 has a fatigue strength of more than 50% of the static fatigue strength of 1 million times. A hydrated solidified body as described in claim 6 or 7 for use in an intertidal zone, a droplet zone, or a land zone along the sea. The hydrated solidified body according to claim 6 or 7, which is used for a member having a weight of 1 ton or more.