JP2014201497A - Method for producing hydrated matrix and hydrated matrix - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a hydrated matrix, which can provide the hydrated matrix that has high durability even in an environment where cyclic stress is applied to the hydrated matrix.SOLUTION: There is provided the method for producing a hydrated matrix by kneading a granular steel-making slag and a SiO-containing substance with water. The method uses the steel-making slag which has a powdering rate of 2.5 mass% or less after being immersed in warm water having a temperature of 80°C for 10 days and has a coarse granule ratio of 4.5 or more, and uses as the SiO-containing substance, a blast furnace slag fine powder, or the blast furnace slag fine powder and fly ash.

Description

The present invention relates to a method for producing a hydrated solid product produced by kneading a granular steel-making slag and a SiO ₂ -containing substance with water.

  Slag generated in the steelmaking process (hereinafter abbreviated as “steelmaking slag”) has a high basicity and contains a large amount of free CaO. For this reason, since steelmaking slag is easy to expand | swell by a hydration reaction, it is not suitable for the use as a civil engineering / construction material like a blast furnace slag, and is difficult to process. Therefore, in recent years, a technique for actively utilizing steelmaking slag has been proposed in order to overcome such a situation. Specifically, Patent Document 1 contains 50% or more of one or two of an aggregate containing steelmaking slag, a silica-containing material having latent hydraulic properties, and a silica-containing material having pozzolanic reactivity. Thus, a hydrated solid body produced by mixing a binder that solidifies by a hydration reaction is described. Patent Document 2 discloses a steel slag obtained by pulverizing and crushing all of a binder, fine aggregate, and coarse aggregate, and using a steel slag mixed with blast furnace slag and steelmaking slag as a binder. The slag block to be performed is described.

JP-A-10-152364 JP-A-2-233539 Japanese Patent No. 3654122 Japanese Patent No. 4438307

  However, when the inventors of the present invention made a trial production of a hydrated solid body using steelmaking slag as a raw material by using the production methods described in Patent Documents 1 and 2, the following problems were revealed.

  That is, according to the manufacturing method described in Patent Document 1, when converter slag is used as steelmaking slag, the hydrated solidified body may not be satisfactory when cured in water at 20 ° C. . Therefore, as a result of investigating this cause in detail, the CaO and MgO components added in the steelmaking process remain without being dissolved in the slag, or precipitate during cooling, and in the form of CaO and MgO in the slag. It was found that the hydrated solidified body collapses when this CaO content or MgO content hydrates and expands under water curing. On the other hand, when the steelmaking slag including the binder is mainly used as in the manufacturing method described in Patent Document 2, in most cases, the compressive strength of the hydrated solidified body is not sufficient and stable. It was difficult to develop strength and could not be used as a substitute for cement and concrete.

  In order to solve such problems, a method for producing a hydrated solid body using a material mainly composed of blast furnace slag fine powder as a binding material has been proposed and put into practical use, while limiting the types of steelmaking slag. ing. In this production method, hot metal pretreatment slag is used as the steelmaking slag, and the ratio of particles having a particle size of 1.18 mm or less is within the range of 15 to 55% by mass of the total amount excluding water. 3. Patent Document 4 describes a technique for producing a stable hydrated solid body by limiting the powdering rate of steelmaking slag.

  Accordingly, the inventors of the present invention have confirmed that good characteristics can be obtained in terms of strength and volume stability as a result of producing a hydrated solid body based on these findings. However, as a result of conducting follow-up studies by exposing the hydrated solids obtained in this way to various environments, there are no particular problems when they are used immersed in the sea or rivers. When exposed to rain or sunshine on the belt or on land, it has been found that there are rare cases where large-scale cracks and damage occur after several years. About this, in the range which removed the core etc. from the residual part and evaluated the static compressive strength, the big strength fall was not recognized but the cause which a crack etc. generate | occur | produced was not clear.

  In order to use industrial by-products represented by steelmaking slag more effectively, hydrated solidified products are not limited to being used in the sea or underwater, but can be used as a substitute for wave-dissipating blocks in coastal areas and soil concrete in land areas. It is indispensable to use it for various purposes. In that case, since the hydrated solidified body is used over a long period of time in various natural environments such as air temperature and sunshine, long-term durability is also a necessary characteristic. Conventionally, many studies have been made on the durability resulting from the expansion stability of steelmaking slag. However, even when using steel slag with a stable volume based on past knowledge, there is no problem with small sizes, but durability may be inferior when large products are exposed under certain conditions. I found out that there was a need for countermeasures.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a method for producing a hydrated solid body capable of obtaining a hydrated solid body having high durability even in an environment where repeated stress is applied. There is to do.

  It is said that a powdered steelmaking slag having a low pulverization rate has a function similar to that of aggregate in concrete and partly contributes to the reaction of the binder. There is no special provision for the particle size of steel slag other than 25 mm or less (see “Steel Slag Hydrated Solid Technology Manual” (Coastal Technology Research Center)). Further, as described above, Patent Document 3 describes that the ratio of particles of 1.18 mm or less is within the range of 15 to 55% by mass of the total blending amount excluding water.

  However, the inventors of the present invention kneaded steelmaking slag satisfying this condition under various blending conditions, and as a result of evaluating the exposure of the hydrated solidified body, there is no problem with rubble or small blocks. There are cases where cracks occur when the block is a large block with a weight exceeding 2.5 t as one lump, or placed in an environment where the heat environment and dryness and humidity change cyclically. I found out.

  And the inventors of the present invention have found that the influence of the particle size of the steelmaking slag is extremely large as a result of earnest examination of the cause, and in particular, not only determines the proportion of particles with a fine particle size of 1.18 mm or less, but also the particle size However, the inventors have found that it is important that large particles are present in an appropriate ratio, and have come up with the present invention.

The method for producing a hydrated solid body according to the present invention is a method for producing a hydrated solid body produced by kneading a granular steelmaking slag and a SiO ₂ -containing substance with water, and as the steelmaking slag, A steelmaking slag having a powdering rate of 2.5% by mass or less after being immersed in warm water of 80 ° C. for 10 days and a coarse rate of 4.5 or more is used, and the blast furnace slag is used as the SiO ₂ -containing material. Fine powder or blast furnace slag fine powder and fly ash are used.

  In the above invention, the method for producing a hydrated solid body according to the present invention uses, as the steelmaking slag, a steelmaking slag having a particle size within a range of 0.5 mm or less in a ratio of 10 mass% or more. It is characterized by.

  The method for producing a hydrated solid product according to the present invention is the above-mentioned invention, wherein one or two selected from alkali metal and / or alkaline earth metal oxides, hydroxides, sulfates, and chlorides are used. More than seeds are added in the range of 0.2 to 20% by mass with respect to the total content of blast furnace slag fine powder and fly ash.

  The method for producing a hydrated solid body according to the present invention is the above-described invention, wherein one or more selected from ordinary Portland cement, fly ash cement, and composite cement are contained in total of fine blast furnace slag powder and fly ash. 200 mass% is added as an upper limit with respect to the quantity, It is characterized by the above-mentioned.

  The method for producing a hydrated solid product according to the present invention is the above invention, wherein naphthalene sulfonic acid and / or polycarboxylic acid is mixed with blast furnace slag fine powder, fly ash, and an oxide of alkali metal and / or alkaline earth metal, It is characterized by being added in the range of 0.1 to 2.0 m% by mass with respect to the total content of hydroxide, sulfate and chloride.

  The hydrated and solidified product according to the present invention is characterized by being manufactured using the method for producing a hydrated and solidified product according to the present invention.

  The hydrated solid body according to the present invention is characterized in that, in the above-mentioned invention, the 1 million times fatigue strength after solidification exceeds 50% of the static fatigue strength.

  The hydrated solidified product according to the present invention is characterized in that, in the above-described invention, it is used in a tidal zone, a flying zone, or a land area on the coast of the sea area.

  In the above invention, the hydrated solid body according to the present invention is used for a member having a weight of 1 ton or more.

  ADVANTAGE OF THE INVENTION According to this invention, the hydrated solid body which has high durability also in the environment where a repeated stress is applied can be provided.

FIG. 1 is a diagram illustrating an example of the relationship between the FM value of steelmaking slag and the number of repeated loads until failure. FIG. 2 is a diagram showing an example of the relationship between the slag diameter on the fine grain side 10% and the slump of the kneaded product.

A hydrated solid body produced using steelmaking slag is produced by using a steelmaking slag having low expansion stability as an aggregate equivalent material, and further adding a binder and water and kneading. In the present invention, in order to obtain high durability, steelmaking slag that satisfies the following conditions (1) and (2) including the above is used. Further, in the present invention, as a binder, using a blast furnace slag or blast furnace slag and SiO ₂ containing material such as fly ash.

(1) Low content of expansive minerals such as CaO and MgO and low powdering rate (2) Coarse grain ratio (FM value) of 4.5 or more

  Examples of the steelmaking slag include hot metal pretreatment slag (such as dephosphorization slag and desiliconization slag), converter decarburization slag, electric furnace slag, and the like, and one or more of these can be used. The steelmaking slag preferably has a maximum particle size of 25 mm or less.

In the steelmaking slag, CaO and MgO are mixed in the refining process. Many parts of CaO and MgO form complex oxides with other elements such as SiO ₂ and FeO, but some exist in the state of free CaO and free MgO. If a large amount of free CaO or free MgO remains as it is, it reacts with moisture to become Ca (OH) ₂ or Mg (OH) ₂ and expands. These mineral phases can be kept low by controlling the composition and cooling of the steelmaking slag.

By freezing steelmaking slag in the outdoor yard for a long time or by steam aging to promote the hydration reaction, free CaO and free MgO are converted into Ca (OH) before being used for the production of hydrated solidified bodies. _By changing to ₂ or Mg (OH) ₂ , there is no problem when used as an aggregate equivalent material. About this, if the steelmaking slag to be used has a ratio of 2.5% by mass or less when heated at 80 ° C. for 10 days with warm water, the strength of the hydrated solidified body is not affected, and the stress When used in small product applications that are less susceptible to environmental changes, there is no effect on product damage.

  Based on conventional knowledge, only a ratio of particles with a particle size of 1.18 mm or less was specified for steelmaking slag, and a large block was manufactured and exposed to land and tidal zones. Was observed to occur. Applications using large shapes need to be large, in other words, it is not desirable that the weight of a single unit be reduced due to breakage during use. Therefore, high durability is required compared to uses such as stone substitutes.

  As a result of earnest investigation on the conditions that do not cause breakage based on the raw material composition and material characteristics of such a large shape, but not only the ratio of the fine particle size of the steelmaking slag used, the balance of the overall particle size It was found that the durability greatly changes depending on the condition. Steelmaking slag is different from natural stone, and uses a product obtained by solidifying and crushing the melt as a by-product.Therefore, the particle size varies depending on the subsequent use. Was found to be important.

  Therefore, when a repeated load having a strength equivalent to 50% when the static fracture strength of each condition is 100%, how many times the load was applied was examined. As a result, it was found that when the characteristics of the aggregate were evaluated by FM (Fitness Modulus) value, which is an index of particle size, the relationship became clear. That is, the particle size distribution is measured by sieving with sieves having a sieve opening of 37.5, 19.0, 9.50, 4.75, 2.36, 1.18, 0.60, 0.30, and 0.15 mm. Then, when the number of fractures is examined by summing up the mass percentages remaining on the sieve and dividing by 100 as FM value, as shown in FIG. It has been found that fatigue durability exceeding 1 million times can be secured at 4.5 or more, and fatigue durability at 2 million times or more can be secured at an FM value of 4.8 or more. That is, it has been found that when the FM value of steelmaking slag is 4.5 or more, more desirably 4.8 or more, a highly durable hydrated solid body can be obtained.

  In addition, in this specification, a large-sized member means a member having a weight exceeding 1 ton as a single body. For a member having a weight of less than 1 ton, stable performance can be roughly obtained even if the FM value is less than 4.5. However, when a part of the structure is structurally loaded or when the wet and dry fluctuation is large, it is desirable to use a member having an FM value of 4.5 or more even for a member having a weight of less than 1 ton.

  On the other hand, even if the FM value is increased, from the viewpoint of fluidity, the range is naturally limited depending on the construction method and the like, and the FM value should be 6.4 or less, more preferably 6.0 or less. Is preferred. For example, when only steelmaking slag of about 5 mm is used, the fluidity of the kneaded material is lowered and the workability is deteriorated. For this reason, the inventors of the present invention further examined the conditions necessary for maintaining workability. As a result, it has been found that the proportion of fine portions of steelmaking slag has a strong influence on kneading and construction.

Therefore, by paying attention to the diameter of the fine particle side 10 weight percent of the slag of steel slag _{(D 10),} the kneaded product in the same formulation (water 198 kg / ^{m 3,} the binder 527kg / ^{m 3,} steelmaking the remainder slag) when checking the slump, as shown in FIG. 2, if the D ₁₀ of was below 0.5mm, in other words, if the ratio of particles less than 0.5mm were more than 10 mass%, good Workability was maintained. On the contrary, if the D ₁₀ of exceeds 0.5mm is, 0 cm in order to top of the specimen at the time of disconnect the slump cone had collapsed sideways without sinking, as an evaluation of the slump It was.

  In the present invention in which the FM value is increased throughout the particle size, that is, the durability is ensured by increasing the number of coarse particles, steelmaking slag having an appropriate particle size distribution such that the ratio of particles of 0.5 mm or less is 10% or more is used. Thus, it is possible to ensure high durability and good kneading / constructing properties.

  By using the slag, it is possible to obtain a solidified body having high durability by using steelmaking slag as an aggregate. Because of its high durability, it can be used not only for small applications but also for large members whose weight exceeds 1 ton. Especially for coastal tidal and splash zones where wetness and dryness are repeated, on land where rainfall and sunshine are repeated, etc., as a substitute for natural stones, as well as for concrete blocks such as wave-dissipating blocks It is possible to use.

  In the present invention, long-term durability is ensured by using the steelmaking slag as described above. In addition, oxides and hydroxides of alkali metals and / or alkaline earth metals, One or more selected from sulfates and chlorides may be added in an amount of 0.2% by mass or more. Thereby, the initial strength of the hydrated solid body can be expressed stably, the solidification can be promoted, and the time required for curing can be shortened. Although the upper limit of the addition amount is not particularly limited, the effect is saturated even if added over 20% by mass, so the upper limit of the addition amount is 20% by mass.

When the production location of the blast furnace slag fine powder is far from the production place of the solidified body, such as when it is not economically advantageous to obtain a large amount of blast furnace slag fine powder, or an oxide of alkali metal and / or alkaline earth metal, If hydroxides, sulfates, and chlorides are difficult to obtain, ordinary Portland cement, fly ash cement, and composite cement can be used as an auxiliary material for the SiO ₂ -containing material. In this case, the particle size composition of the fine powder portion changes, and steelmaking slag having a high specific gravity is easily separated.

  Addition of naphthalene sulfonic acid and / or polycarboxylic acid improves kneadability when the raw material is kneaded with water. Therefore, the amount of water required for kneading can be reduced, and as a result, a higher strength hydrated solidified product can be obtained. Effective if the addition amount is less than 0.1% by mass with respect to the total content of blast furnace slag fine powder, fly ash and alkali metal and / or alkaline earth metal oxides, hydroxides, sulfates and chlorides Since the effect is saturated even if it is added in excess of 2.0% by mass, the addition amount is limited to the range of 0.1 to 2.0% by mass.

〔Example〕
In the present Example, the hydrated solid body was produced using the granular steelmaking slag which adjusted the particle size. As the granular steelmaking slag, the hot metal pretreatment slag generated when the blast furnace hot metal discharged from the blast furnace was dephosphorized was used. In addition, blast furnace granulated slag fine powder and fly ash were used as the binder, and ordinary Portland cement was used as the alkali stimulating material. The particle size of the steel slag used in the test, FM value, and D ₁₀ represent respectively the particle diameters was selected as the condition of the range of the present invention and comparative. At that time the particle size, FM value, and _{D 10} shown in Table 1.

Powdered steelmaking slag, a binder, an alkali stimulant, and water were kneaded using a mixer with the formulation shown in Table 2. In order to evaluate workability, the slump of the kneaded product was measured by the slump test method of Japanese Industrial Standard JIS A 1101, and then molded into a 10 cm × 10 cm × 40 cm mold. The molded product was deframed after 2 days and cured in water at 20 ° C. for 28 days, and then subjected to a bending fatigue test. The bending fatigue test was repeatedly loaded at a frequency of 7 Hz with the 50% stress as the upper limit stress and the 5% stress as the lower limit stress based on the fracture stress obtained by the bending strength test method of Japanese Industrial Standard JIS A 1106. According to the number of times until destruction occurred, a case where the number exceeded 1 × 10 ⁶ times was judged as “◯”, and a case where the number was less than 1 × 10 ⁶ times was judged as “x”. The slump and durability results are also shown in Table 1.

As shown in Table 1, high durability was obtained when the coarse grain ratio of the steelmaking slag was within the range of the present invention. On the other hand, it was confirmed that durability was not able to be secured enough about the thing with a low coarse grain rate of steelmaking slag. Further, under the condition D ₁₀ of greater, although the durability can be secured, collapse around without the upper part of the specimen pulled slump cone fresh state sinks, could not be measured slump. D ₁₀ is depending largely be shaped and molding method can be molded, in order to workability and finish with a good solidified product, it is desirable to a D ₁₀ in the range of 0.5 or less Was confirmed. As described above, by making it within the scope of the present invention, it has become possible to stably exhibit high durability that has not been achieved in the past.

Claims (9)

A method for producing a hydrated solid body produced by kneading a granular steel-making slag and a SiO ₂ -containing substance with water,
As the steelmaking slag, a steelmaking slag having a pulverization rate of 2.5% by mass or less after being immersed in hot water at 80 ° C. for 10 days and a coarse particle rate of 4.5 or more is used, and contains the SiO ₂ Blast furnace slag fine powder or blast furnace slag fine powder and fly ash are used as a substance, The manufacturing method of the hydrated solid body characterized by the above-mentioned.   2. The method for producing a hydrated solid body according to claim 1, wherein the steelmaking slag is a steelmaking slag having a particle size within a range of 0.5 mm or less of 10% by mass or more. .   One or more selected from oxides, hydroxides, sulfates, and chlorides of alkali metals and / or alkaline earth metals with respect to the total content of blast furnace slag fine powder and fly ash The method for producing a hydrated solid body according to claim 1 or 2, wherein the addition is performed within a range of 0.2 to 20% by mass.   One or more kinds selected from ordinary Portland cement, fly ash cement, and composite cement are added up to 200 mass% with respect to the total content of blast furnace slag fine powder and fly ash. The manufacturing method of the hydrated solid body of any one of Claims 1 thru | or 3.   Naphthalene sulfonic acid and / or polycarboxylic acid with respect to the total content of blast furnace slag fine powder, fly ash, and alkali metal and / or alkaline earth metal oxides, hydroxides, sulfates, and chlorides The method for producing a hydrated solid body according to any one of claims 1 to 4, wherein the addition is performed within a range of 0.1 to 2.0 m% by mass.   A hydrated and solidified product produced using the method for producing a hydrated and solidified product according to any one of claims 1 to 5.   The hydrated solid body according to claim 6, wherein the fatigue strength of 1 million times exceeds 50% of the static fatigue strength.   The hydrated solidified body according to claim 6 or 7, wherein the hydrated solidified body is used in a tidal zone, a flying pine zone, or a land area along a sea area.   The hydrated solidified body according to any one of claims 6 to 8, which is used for a member having a weight of 1 ton or more.

Images