JP2009184173A - Method of manufacturing counter weight - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a counter weight which can use a prepacked construction method for manufacturing the counter weight of construction machinery by a grouting mortar having an excellent flowability containing weight fine aggregate, and to reduce vibration generated when compacting weight concrete used in manufacturing the counter weight. <P>SOLUTION: In the method of manufacturing the counter weight, a rough aggregate is previously filled and the mortar is cast into a clearance of the rough aggregate. The weight fine aggregate contained in the mortar is an aggregate containing at least one of FeO, Fe<SB>2</SB>O<SB>3</SB>, and metallic iron as a main constituent. In the weight fine aggregate, spherical particles contains 20% or more among whole particles, and particles passing through a screen having a nominal size of 0.15 mm are 10-20% by mass percentage among whole particles. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a counterweight using heavy concrete, and more particularly to a method for manufacturing a counterweight using a prepacked construction method in which coarse aggregate and mortar are separated and added.

  As shown in FIGS. 1 and 2, the counterweight is used to ensure the weight balance of the machine. In order to ensure workability and stability, and to work safely and efficiently, the construction machine Etc. For example, in a hydraulic excavator or the like, the work weight is wide, and the counterweight plays a large role in order to ensure the balance of the machine during the work. For this purpose, the counterweight is made of a material with high specific gravity so that it is as compact and heavy as possible. There are various types of counterweights, but canned counterweights are made of steel from steel plates and filled with heavy concrete.

  As a material used for a counterweight of a construction machine or the like, generally heavy concrete using heavy aggregate is used. Conventionally, the heavy concrete has been filled with a low slump and compacted with a strong vibration force. That is, heavy coarse aggregate, heavy fine aggregate, cement, water, and an admixture are mixed together, and are compacted by vibration and filled. As a result, extremely large vibrations and noises are generated at the time of compaction, which is a problem.

  On the other hand, a prepacked method of separating and placing coarse aggregate and cement paste or mortar is known (for example, see Non-Patent Documents 1 and 2). The “pre-packed construction method” refers to a construction method in which a coarse aggregate is introduced in advance and mortar or the like is injected into the gap between the coarse aggregates to make concrete. According to the pre-packed method, large vibration and noise are less likely to occur during filling.

  Here, since the mortar (injection mortar) used for the prepacked construction method needs to spread well to the fine gap of the coarse aggregate, it was necessary to have good fluidity. However, heavy weight mortar using heavy fine aggregates is often used as heavyweight concrete for counterweights, but there are few heavy mortars with good fluidity. That is, almost no injection mortar using heavy fine aggregate has been known. Therefore, it was not possible to manufacture a counterweight by a prepacked method by injecting a heavy mortar containing heavy fine aggregate.

  Therefore, when manufacturing the counterweight, the “prepacked construction method having the feature that large vibrations and noises are less likely to occur” cannot be used. Therefore, large vibrations and noises have always been generated.

On the other hand, “heavy concrete” is concrete having a unit volume weight larger than usual, and iron ores such as magnetite and hematite have been frequently used as heavy aggregates used in heavy concrete. However, it is becoming difficult to obtain high-quality heavy aggregates, and the use of expensive natural resources is not preferable from the viewpoints of economy and environmental considerations. Therefore, as a substitute for iron ore aggregate, slag with a high iron content such as electric furnace oxidation slag is also used, but the density is often less than 4 g / cm ^{3 and} has sufficient density as a heavy fine aggregate. It is difficult to obtain. In addition, a heavy concrete is proposed in which cement is mixed with steelmaking converter dust (see, for example, Patent Document 1). However, in order to use it as it is as a fine aggregate of concrete or mortar, the particle diameter of the steelmaking converter dust is not sufficient, and only coarse particles divided by a sieve can be used. In addition, a technique has been proposed in which cement is mixed with fine dust and granulated to form a pellet having a diameter of 200 μm or more and used as an aggregate (see, for example, Patent Document 2). It was high.

  Further, Patent Document 3 proposes to use steel fine particles for shot blasting having a sieve nominal size of 2.5 mm to 0.15 mm as a heavy fine aggregate of heavy concrete by adjusting the particle size. However, it has been extremely difficult to adjust the particle size by blending expensive steel fine particles for shot blasting prepared by adjusting to uniform particle sizes of various sizes, so that commercial application has not progressed. It has also been proposed to use granular pig iron separated from granulated blast furnace slag as a material for heavy aggregate for heavy concrete instead (see, for example, Patent Document 4). However, these fine aggregates for heavy concrete have a problem that a sufficient mortar flow cannot be obtained, or separation of the aggregate and the cement paste may occur.

As described above, the above technique has many problems as heavy fine aggregates. Therefore, it is a heavy mortar using heavy fine aggregates, and has good fluidity to the extent that it is used in the prepacked construction method. There was nothing satisfactory. For this reason, the pre-packed method cannot be used in the manufacture of the counterweight, and thus it has not been possible to prevent the generation of extremely large vibrations and noises during compaction.
JP-A-5-31880 Japanese Patent Laid-Open No. 6-024813 Japanese Patent Laid-Open No. 2-172846 JP 2004-210574 A Established in 2002: Standard Specification for Concrete [Construction], p. 332 The main points of concrete technology '06, Japan Concrete Engineering Association, ed., 380 pages (2006)

  The present invention develops a heavy fine aggregate that is excellent in fluidity when made into a mortar, has an appropriate particle size and density, and is advantageous in terms of cost, and has good fluidity and contains the fine fine aggregate. To provide a counterweight manufacturing method that enables the use of a pre-packed method for the construction of counterweights for construction machinery and ultimately reduces the vibrations that occur when compacting heavy concrete used in counterweight manufacturing. It is in.

  The present inventor compared various recycled materials having sufficient density as a heavy fine aggregate, and as a result of earnestly researching the optimum particle shape and particle size distribution as a heavy fine aggregate, a specific heavy fine aggregate has the above-mentioned problems. I found that it can be solved. And when the injection | pouring mortar containing the heavy fine aggregate was used, it discovered that a prepacked construction method could be used for manufacture of a counterweight, and came to this invention.

That is, the present invention is a method for producing a counterweight in which coarse aggregate is pre-filled and mortar is injected into the gaps between the coarse aggregates, and the heavy fine aggregate contained in the mortar is the main component. It is an aggregate containing at least one of FeO, Fe ₂ O ₃ and metallic iron as a component, and spherical particles out of all particles are 20% or more, and particles passing through a sieve having a nominal size of 0.15 mm are all particles. The present invention provides a method for producing a counterweight, characterized in that it is a heavy fine aggregate having a mass percentage of 10% to 20%.

  Further, the present invention provides that the above-mentioned heavy fine aggregates are “mill scale generated in the steelmaking rolling process”, “coarse fraction screened with a particle size of 50 μm among steelmaking converter dust” and “blast furnace granulation” The present invention provides a method for producing the counterweight obtained by mixing at least one selected from the group consisting of “granular pig iron separated from slag” and a hot scarf.

  Moreover, this invention provides the counterweight manufactured using said manufacturing method of the counterweight.

  According to the method for producing a counterweight of the present invention, the heavy fine aggregate in the mortar used therein has an appropriate particle size distribution required for the heavy fine aggregate of concrete or mortar, and appropriately contains spherical particles. Appropriate fluidity and workability can be given to the fresh properties of concrete and mortar. Moreover, by using such a specific heavy fine aggregate, even if the water content in the mortar is increased and the viscosity is lowered, the aggregate and the cement paste are hardly separated.

Further, since it has a sufficiently large density as a heavy fine aggregate having a density of 4 g / cm ³ or more, a high-density counterweight can be suitably manufactured, and a fluid mortar containing such heavy fine aggregate has good fluidity. This makes it possible to use a pre-packed method for manufacturing the counterweight. In addition, by using specific heavy aggregates, it is possible to easily clear the flow time, bleeding rate, expansion rate, etc. by the P funnel, which are conditions to be satisfied by the injection mortar for the prepacked construction method. The prepacked construction method can be suitably used for the production of

  And by being able to use the pre-packed method, it is possible to eliminate or reduce the vibration for compacting heavy concrete that occurs during counterweight production, and it is possible to eliminate voids that are not filled with mortar, It is possible to manufacture a counterweight that is uniformly filled and has a high density as a whole.

  Furthermore, since the heavy fine aggregate used in the present invention is obtained by mixing recycled materials generated in the steel making process, it is extremely advantageous in terms of cost and is an expensive natural resource that is feared to be exhausted. It is effective as an alternative to iron ore aggregate.

  Hereinafter, although the manufacturing method of the counterweight of this invention is demonstrated in detail, this invention is not limited to the following specific aspects, It can change arbitrarily within the range of a technical idea.

The present invention is a method for producing a counterweight using a pre-packed method, wherein the heavy fine aggregate contained in the injection mortar used at that time is “at least of FeO, Fe ₂ O ₃ , and metallic iron as main constituent components”. The aggregate includes one, the spherical particles are 20% or more of all particles, and the particles passing through a sieve having a nominal size of 0.15 mm are 10% to 20% by weight of all particles. "Aggregate".

In the present invention, “heavy fine aggregate” refers to a fine aggregate having a surface dry density of 4 g / cm ³ or more, and “fine aggregate” passes through a 10 mm net sieve and 85 mass of a 5 mm net sieve. The aggregate which passes more than%.

The heavy fine aggregate used in the method for producing a counterweight according to the present invention includes at least one of FeO, Fe ₂ O ₃ , and metallic iron as a main component. “Containing at least one of FeO, Fe ₂ O ₃ , and metallic iron as a main constituent” means containing iron in the form of such an oxide or metal, and regarding the content of iron in the heavy fine aggregate particularly but are not, it is preferable Fe ₂ O ₃ when the constituent elements was determined in terms of oxide by X-ray fluorescence analysis is not less than 65%. When Fe ₂ O ₃ is less than 65% when the constituent elements are calculated in terms of oxides by fluorescent X-ray analysis, the aggregate dry density of the aggregate may be less than 4 g / cm ³ . More preferably, Fe ₂ O ₃ is 75% or more when the constituent elements are calculated in terms of oxide by fluorescent X-ray analysis, and the surface dry density of the heavy fine aggregate at this time is 4.5 g / cm ^3. That's it. Accordingly, the surface dry density of the heavy fine aggregate used in the method for producing a counterweight according to the present invention is preferably 4.5 g / cm ³ or more.

  The heavy fine aggregate has a large density difference from the cement paste, so that the aggregate and the paste are easily separated when placing concrete or mortar. Therefore, fluidity needs to be ensured by the shape of the heavy fine aggregate. The injection mortar used in the prepacked method in the method for producing a counterweight according to the present invention is required to have particularly high fluidity.

  The heavy fine aggregate used in the present invention contains 20% or more of spherical particles (the definition will be described later) among all particles, so that it has high fluidity and can be separated from cement paste when used in concrete or mortar. Absent. When the spherical particles are less than 20%, the aggregate and the cement paste may be separated during the injection of the injection mortar in the prepacked method. In addition, since mortar containing heavy fine aggregate whose spherical particles are less than 20% has poor fluidity, the mortar may not spread over the gaps in the coarse aggregate in the prepacked construction method. Moreover, in order to spread, it will be necessary to add a vibration and the effect of this invention may not be acquired.

The optimum particle size of the fine aggregate used for concrete and mortar varies depending on the shape of the aggregate, surface roughness, blending, and the like. For example, in the JIS standard for crushed sand (A 5005), the particle size distribution is defined as shown in Table 1, and particles passing through a sieve having a nominal size of 0.15 mm are 2% to 15% in terms of mass percentage of all particles. Yes. On the other hand, in the JIS standard (A 5011-4) for electric furnace oxidation slag aggregate, it is shown in the description that a better quality of fresh concrete can be obtained by increasing the amount of fine particles. In the furnace oxidation slag aggregate, particles passing through a sieve having a nominal size of 0.15 mm are 10% to 30% in terms of mass percentage of all particles. However, there is knowledge about the optimum particle size distribution for obtaining good fresh concrete properties in a heavy fine aggregate having a density of 4.5 g / cm ³ or more and containing 20% or more of spherical particles among all particles. It has never been published.
Japanese Industrial Standard JIS A 5005: Crushed stone and crushed sand for concrete Japanese Industrial Standard JIS A 5011-4: Slag aggregate for concrete Part 4, Electric furnace oxidation slag aggregate

  Patent Document 3 shows that steel fine particles for shot blasting are blended and used as heavy aggregates for heavy concrete, but stipulated in JASS5 (Architectural Institute of Japan Architectural Construction Standard Specification 5 Reinforced Concrete Work) The detailed particle size distribution of the heavy fine aggregate for obtaining good fresh properties of concrete and mortar has not been studied only by adjusting the particle size distribution so as to satisfy the specified particle size distribution.

  The inventor examined the particle size distribution of the heavy fine aggregate for obtaining a good mortar flow in detail, and found the optimum particle size distribution shown in Table 1. That is, the heavy fine aggregate in the method for producing a counterweight according to the present invention is characterized in that particles passing through a sieve having a nominal size of 0.15 mm are 10% to 20% in terms of mass percentage of all particles. When the particles passing through a sieve having a nominal size of 0.15 mm are less than 10% by mass or more than 20% of the total particles, sufficient mortar flow cannot be obtained, or separation of aggregate and cement paste May occur.

  Further, it is preferable that the particles passing through the sieve having a nominal size of 1.2 mm are 70% to 90% in terms of mass percentage of all particles. When particles passing through a sieve having a nominal size of 1.2 mm are less than 70% by mass or more than 90% of the total particles, sufficient mortar flow cannot be obtained, or separation of aggregate and cement paste May occur. Furthermore, the heavy fine aggregate in the method for producing a counterweight according to the present invention is preferably obtained by mixing recycled materials generated in the steel making process.

In the steel slab cast by the continuous casting slab, inclusions such as Al are continuously deposited on the surface layer in the longitudinal direction of the steel slab by the molten steel injection flow into the mold. The hot scarf of recycled material generated in the process of melting and removing the surface inclusions in the steel slab contains FeO, Fe ₂ O ₃ and metallic iron as main constituent components, and the constituent elements are converted to oxides by fluorescent X-ray analysis. When Fe ₂ O ₃ is 80% or more, the surface dry density is 4.8 g / cm ³ or more. Further, spherical particles occupy about 70%, and particles passing through a sieve having a nominal size of 0.15 mm are in the range of 10% to 20% in terms of mass percentage of all particles. Accordingly, the heavy fine aggregate in the present invention preferably contains a hot scarf, and the hot scarf can be used alone as it is as the heavy fine aggregate in the present invention.

  However, the amount of the recycled material (hot scarf) generated is not so large, and it is more preferable to use it with other recycled materials. For example, if “coarse powder sieved at 50 μm out of converter dust for steel making” (hereinafter, the parentheses are abbreviated as “coarse dust of converter dust”), the hot scarf 70 is converted into a converter. If the mixing volume ratio is up to the coarse dust fraction 30, mixing is possible. If the converter dust coarse particles are further mixed, the particles passing through the sieve having a nominal size of 0.15 mm exceed 20% in terms of mass percentage of the total particles, so that a sufficient mortar flow may not be obtained. Incidentally, here, the “volume” is an absolute volume not including the volume of the void portion between the aggregate particles, and the “volume” per unit mass of each material is the surface dry density measured by JIS A 1109. Reciprocal. The mixing volume ratio is an internal mixing ratio of “volume” of each fine aggregate in mortar or concrete blending.

“Granular pig iron separated from blast furnace granulated slag in the grinding process” (hereinafter abbreviated as “granular pig iron” in parentheses) also has a surface dry density of 4.8 g / cm ³ or more mainly composed of metallic iron. At the same time, it is a recycled material that contains about 50% of particles having a shape close to a sphere, and can be suitably mixed with a hot scarf. The hot scarf 70 can be mixed up to the volume ratio of the granular pig iron 30. When granular pig iron is further mixed, the particles passing through the sieve having a nominal size of 0.15 mm are less than 10% in terms of mass percentage of the total particles, so that a sufficient mortar flow may not be obtained.

The mill scale of the recycled material generated in the steelmaking rolling process (hereinafter abbreviated as “mill scale” in parentheses) also contains FeO, Fe ₂ O ₃ , and metallic iron as main components, and the constituent elements are fluorescent X Fe ₂ O ₃ is 80% or more when calculated in terms of oxide by line analysis, and the surface dry density is 4.8 g / cm ³ or more. Moreover, it shifts to the coarse grain side a little from a hot scarf, has a particle size distribution close to crushed sand JIS, and has a relatively large generation amount as a recycled material. Accordingly, as the heavy fine aggregate in the present invention, those containing a mill scale are also preferable.

  However, since the particle shape of the mill scale is often flat, the fluidity of concrete and mortar tends to decrease when used as heavy aggregate, and when the unit water amount or water reducing agent amount is excessively increased Aggregate and paste may be easily separated. Therefore, it may not be preferable to use the mill scale alone as a heavy fine aggregate.

  This inventor mixed the hot scarf and the mill scale by various mixing ratios, and examined the appropriateness as a heavy fine aggregate. As a result, it was confirmed that the hot scarf 30 could be mixed up to the volume ratio of the mill scale 70. When the mill scale is further mixed, the ratio of the spherical particles is less than 20%, the fluidity cannot be ensured, and a sufficient mortar flow may not be obtained. Furthermore, when the unit water amount is increased in order to obtain a mortar flow, the aggregate and the cement paste may be separated.

  Furthermore, when the mixing volume ratio of the hot scarf and the mill scale is 40:60 or the ratio of the hot scarf is larger than that, it is more preferable because air can easily escape from the mortar and the unit volume mass of the mortar can be increased. That is, in terms of the volume ratio of hot scarf / mil scale, the amount of hot scarf generated as recycled material, fluidity of mortar, difficulty in separating heavy aggregate and cement paste, density of mortar, etc. The value is preferably 100/0 to 30/70, more preferably 90/10 to 40/60, and particularly preferably 80/20 to 50/50.

  Here, the “spherical particles” in the present invention will be described in detail. A “spherical particle” is a particle having a shape close to a true sphere. In the process of producing spherical particles, (1) when a solid is melted into a liquid state by heat and then cooled and solidified in the air, it becomes a shape close to a sphere with the smallest surface area per volume. (2) non-spherical particles However, when the particles lose their corners by physical polishing and become a shape close to a sphere, (3) the fine particles precipitated from the powder or the solution may bind around the core and grow into a shape close to a sphere. (2) In the case of (3), particles having a continuous shape from a spherical shape to a non-spherical shape are generated, but in the case of (1), particles having an intermediate shape are not generated.

  As described above, the hot scarf is a recycled material that is generated in the process of removing and removing the surface layer inclusions of the steel slab, and spherical particles are generated in the generation process (1). Spherical particles are also included in the converter dust coarse particles and the granular pig iron, but it is considered that the generation process includes not only (1) but also (2).

  The fine aggregate in the method for producing a counterweight according to the present invention is required to have 20% or more of “spherical particles” among all particles, but “spherical particles having a strain unevenness degree of 3.3 or less described below. "Is preferably 20% or more of all particles.

Here, the “strain unevenness” is defined by the following equation.
[Strain unevenness]
= [Perimeter of particle outline] / [diameter of a circle with the same area as the area surrounded by the particle outline]
That is, by visually observing a scanning electron microscope (SEM) image, particles that can be judged to be discoid or hemispherical from the shadow are excluded, and particles that are clearly close to a sphere are image-processed and analyzed. The image processing may be performed using general image processing software [for example, Adobe Photoshop (registered trademark of Adobe Systems Inc.)]. First, a contour-only figure is created by removing shadows from an image of particles close to a sphere, and the area of the figure and the perimeter of the outline are obtained. The figure is approximated to a circle (assuming a circle having the same area as the figure), the radius r is obtained from the area πr ^{2 of} the circle, and the diameter is obtained by doubling the radius r. The ratio of the circumference length to the diameter becomes smaller as the contour is closer to a perfect circle, that is, the closer the particle is to a sphere, and the value is closer to the circumference ratio π. Incidentally, in the spherical particles contained in the hot scarf, the degree of strain unevenness is 3.2 or less.

  Moreover, when calculating | requiring the ratio of the spherical particle among all the particles, the number of all the particles reflected in the several SEM photograph and the number of spherical particles are counted, and an average is calculated | required, but the ratio of a spherical particle irrespective of the particle size of particle | grains Is assumed to be constant, and only the particles having a constant particle diameter of 50 μm or more are counted, and the total number of particles and the number of spherical particles thereof are counted. “%” In the ratio of spherical particles means “number%”.

  On the other hand, the heavy fine aggregate in the method for producing a counterweight according to the present invention includes “mill scale generated in a steelmaking rolling process”, “coarse fractions screened with a particle size of 50 μm among steelmaking converter dust” and It can also be obtained by mixing at least two selected from the group consisting of “granular pig iron separated from granulated blast furnace slag”. The mill scale, the converter dust coarse particles, and the granular pig iron are all recycled materials that are generated in a larger amount than the hot scarf that is generated in the steel slab surface cutting process.

The mill scale is a recycled material generated in the rolling process of steel making. Fe ₂ O ₃ is 80% or more when the constituent elements are determined in terms of oxides by fluorescent X-ray analysis, and the surface dry density is 4.8 g / cm. ³ or more. Moreover, as shown in Table 2, it has a particle size distribution close to crushed sand JIS. However, since the particle shape is often flat, when used as an aggregate, the fluidity of concrete and mortar tends to decrease, and when the amount of unit water or water reducing agent is excessively increased, the aggregate and paste Easy to separate. Therefore, it may not be preferable to use the mill scale alone as a heavy fine aggregate.

  The coarse fraction of converter dust for steel making contains 70% or more of spherical particles, but particles passing through a sieve having a nominal size of 0.15 mm have a mass percentage of 25% or more of all particles, and a sieve having a nominal size of 0.3 mm. When passing particles are 65% or more, the aggregate particle size distribution is too biased toward the fine particle side, so the particles are prone to agglomerate, which is sufficient when the coarse dust from the converter dust is used alone as a heavy fine aggregate It is difficult to obtain a good mortar flow.

  Particulate pig iron separated from granulated blast furnace slag also contains about 50% spherical particles, but particles passing through a sieve with a nominal size of 0.15 mm are 5% or less by mass of the total particles and have a nominal size of 0.3 mm. While the particles passing through the sieve are 20% or less, the particles passing through the sieve having a nominal size of 1.2 mm are 85% or more, and the particle size distribution is concentrated between 0.3 mm and 1.2 mm. Have. Therefore, when granular pig iron is used alone as a heavy fine aggregate, the heavy fine aggregate and the cement paste may be easily separated.

  As described above, when all of the three kinds of recycled materials are used alone as heavy fine aggregates, a sufficient mortar flow cannot be obtained, or the aggregate and the cement paste are easily separated. However, by mixing at least two of the three types of recycled materials at an appropriate mixing ratio, the aggregate and the cement paste are not separated, and sufficient fluidity and workability can be given to the mortar. Heavy fine aggregate is obtained. Therefore, such mortars having excellent fluidity using such heavy fine aggregates are particularly suitable as injection mortars for prepacked construction methods that require particularly high fluidity.

  In the weight fine aggregate in the counterweight manufacturing method of the present invention, the mixing ratio of the mill scale, the converter dust coarse particles, and the granular pig iron is 0 to 70%, 0 to 50%, and 0 to 0 in mass percentages, respectively. It is preferably 60%, particularly preferably 20 to 70%, 20 to 50%, and 0 to 40%.

  When the mixing ratio of the mill scale exceeds 70% by mass or when the mixing ratio of the converter dust coarse particles exceeds 50%, the mortar using the heavy fine aggregate cannot obtain a sufficient mortar flow, It may not be preferable for a prepacked construction method in which mortar requires particularly excellent fluidity. When the mixing ratio of the granular pig iron exceeds 60%, the aggregate and the cement paste may be separated in the mortar using the heavy fine aggregate.

  When the mixing ratio of the mill scale is less than 20%, in the mortar using the heavy fine aggregate, depending on the mixing ratio of the remaining recycled material, the separation of the aggregate and the cement paste occurs, or the sufficient mortar flow May not be obtained. When the mixing ratio of the converter dust coarse particles is less than 20%, or when the mixing ratio of the granular pig iron exceeds 40%, the mortar using the heavy fine aggregate may depend on the mixing ratio of the remaining recycled materials. Separation of aggregate and cement paste may occur.

  The counterweight manufacturing method of the present invention is based on a prepacked construction method in which a coarse aggregate is preliminarily filled and injection mortar containing the above-mentioned specific heavy fine aggregate is injected into a gap between the coarse aggregates. And The prepacked construction method is used for underwater construction, radiation shielding construction, reverse concrete construction, and the like, but the known method can also be applied to the counterweight manufacturing method of the present invention.

  The properties of the injection mortar used in the pre-packed method are that the flow time through the P funnel is 16 to 20 seconds so that the injection mortar reaches the fine voids of the coarse aggregate; In order to reduce material separation, the bleeding rate at 3 hours after the start of the test is 3% or less; the expansion rate is 5 to 10% for proper expansion; until the injection is completed Although the fluidity is maintained; the drying shrinkage is small (see Non-Patent Document 1), the injection mortar containing the above-mentioned specific heavy fine aggregate used in the present invention has all these conditions. Since it is almost satisfied, the counterweight can be manufactured without problems using the prepacked method. As the mortar used in the method for producing a counterweight according to the present invention, those satisfying the above conditions are preferable.

  There is no limitation in particular about the cement used for this invention, The thing generally used for the prepacked construction method can be used. Ordinary Portland cement, fly ash cement, blast furnace cement and the like can be suitably used. It is also preferred to use fly ash to improve fluidity. The admixture used in the present invention is not particularly limited, and a known water reducing agent or antifoaming agent is used. Moreover, what is marketed as an admixture for pre-packed concrete can also be used conveniently.

  In the present invention, the coarse aggregate to be filled in advance is not particularly limited, and those used in the prepacked construction method can be used. “Coarse aggregate” means an aggregate in which 85% by mass or more remains with a 5 mm sieve, but the coarse aggregate used in the prepacked construction method is defined as having a minimum dimension of 15 mm or more (see Non-Patent Document 1). ) And such can be suitably used.

  There is no particular limitation on the material of the coarse aggregate in the counterweight manufacturing method of the present invention, and conventional iron ore can be used, but the use of expensive natural resources is economically and environmentally friendly. May not be preferable. Moreover, an electric furnace oxidation slag coarse aggregate can also be used. In the present invention, one of the purposes is to use resources that are not sufficiently utilized industrially, and it is preferable to use artificial stone materials manufactured by melting resources containing dust generated in the steelmaking process. In particular, slag produced by mixing dust generated during steelmaking and powdered reduced slag, heating and melting, and cooling and solidifying is freed from free lime and low boiling point metal oxides during the melting process. Moreover, since it has sufficient density as a weight coarse aggregate, it is preferable as the coarse aggregate in the present invention.

  In the weight mortar for injection in the method for producing a counterweight of the present invention, it is preferable to reduce the unit water amount and to add a water reducing agent in order to ensure high density. As the water reducing agent, lignin type, naphthalene sulfonic acid type, melamine type, polycarboxylic acid type water reducing agent; AE water reducing agent; high performance water reducing agent; high performance AE water reducing agent can be used. Among these, it is preferable to use a high performance AE water reducing agent having a large water reducing effect. In order to secure a high density, it is desirable to add an antifoaming agent particularly when it is necessary to suppress the introduction of air.

The aggregate maximum dimension, the unit water amount of the injected mortar, and the water cement ratio (the water-powder ratio when an admixture such as fly ash is used) can be appropriately selected according to the application. Since it is molded as a can-made counterweight, a high filling property can be obtained by setting the bleeding rate after P funnel flow-down time of 15 to 30 seconds and within 3% after 3 hours. In the present invention, the maximum size of the coarse aggregate is preferably 80 to 20 mm, particularly preferably 40 to 20 mm. The maximum size of the fine aggregate is preferably about 5 to 1.2 mm, particularly preferably about 1.2 to 2.5 mm. Unit water injection mortar is preferably ^{250~350kg / m 3, 270~320kg / m} 3 is especially preferred. The water powder ratio is preferably 0.45 to 0.65, particularly preferably 0.50 to 0.60.

  As a prepacked construction method in the counterweight manufacturing method of the present invention, a general method can be applied and there is no particular limitation. First, a mold for a counterweight is manufactured, and a mortar injection tube or a test tube is directed toward the inside. Install, put coarse aggregate, work on top of coarse aggregate, inject the injected mortar and fill with heavy concrete. At that time, vibration can be applied to compact the heavy concrete, but in the injection mortar using the heavy coarse aggregate of the present invention, it is injected into the mold for the counterweight without any gap without applying such vibration. Therefore, it is preferable not to add vibration from the viewpoint of simplification of work, safety, noise prevention, and the like.

  There is no particular limitation on the size, shape, application, etc. of the counterweight manufactured by the method for manufacturing a counterweight of the present invention, and it can be used for a known size, shape, application, etc. as a can-made counterweight. The size of the can is not particularly limited, but is generally about 1 m to about 2 m in width, about 0.2 m to about 0.5 m in length, and about 0.5 m to about 1.5 m in height. The present invention can be suitably applied to anything. Applications include, for example, excavators (see FIG. 1) such as mini excavators, swivel excavators, and ultra-small swivel excavators (see FIG. 1); hoists (see FIG. 2); forklifts and the like.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples. However, the present invention is not limited to these examples unless it exceeds the gist.

In Table 3, it shows about the raw material of the mortar used for the manufacturing method of the counterweight of Example 1, Example 2, and a comparative example. Table 4 shows the shape and particle size distribution of the heavy fine aggregates used.

Example 1
As the heavy fine aggregate, “50/50 (volume ratio) mixture of hot scarf and mill scale” having a surface dry density of 4.96 g / cm ³ , 2538 kg / m ³ , and ordinary Portland cement (density 3.16 g / cm ³⁾ ) 336 kg / m ³ , fly ash type II (density 2.24 g / cm ³ ) 144 kg / m ³ , polycarboxylic acid-based high-performance AE water reducing agent (BASF Pozzolith Leo Build SP-8S) as an admixture and 84 kg / ^{m 3,} and antifoam (BASF Pozzolith Ltd. micro air 404) 0.19kg / ^{m 3,} and water 288 kg / ^{m 3} as appropriate mixed to prepare a mortar. See Table 5.

Example 2
Mortar was prepared in the same manner as in Example 1 except that the types and amounts of heavy fine aggregate, cement, fly ash, admixture and water were changed as shown in Table 5.

Comparative Example Mortar was prepared in the same manner as in Example 1 except that the type and amount of heavy fine aggregate, cement, fly ash, admixture and water were changed as shown in Table 5.

<Test method and test results>
Table 6 shows the test items and test methods. Table 7 shows the results of testing the fluidity and separation resistance of the mortars of Examples 1, 2 and Comparative Examples by each test.

(1) The mortars of Example 1 and Example 2 had good P funnel flow time and bleeding rate when producing a counterweight according to the present invention.
(2) The amount of unit water necessary for obtaining the same fluidity was smaller in Example 1 and Example 2 than in the comparative example. That is, the fluidity was high.
(3) As shown in Example 2, when a small amount of converter dust coarse particles was mixed, material separation could be reduced, and the bleeding rate was reduced.
(4) In the comparative example, the fluidity could be secured by increasing the unit amount of water, but the material was easily separated and the bleeding rate was increased. That is, it was difficult to achieve both.
(5) The heavy fine aggregate has a large density difference from the cement paste, so that the material is easily separated, and the bleeding rate is larger than the standard value of 3% when the normal aggregate is used. For this reason, it has been found that the present invention is particularly suitable for applications that do not require high adhesion (strength) between coarse aggregate and mortar, such as counterweights, as compared to general civil engineering applications.

Example 3
(Test method)
(1) A hot scarf having a surface dry density of 5.08 g / cm ³ and spherical particles of about 75% and a converter dust coarse particle content of a surface dry density of 5.84 g / cm ³ and spherical particles of about 73% are appropriately mixed, Mixed sands 1-4 having a particle size distribution shown in Table 8 were prepared. (Mixed volume ratio of mixed sand 2; hot scarf 70: converter dust coarse fraction 30)
(2) Ordinary Portland cement is mixed with the mixed sand prepared in (1) at a sand cement volume ratio of 3.19, and 4.37 kg / m ³ of polycarboxylate ether-based high-performance AE water reduction per 547 kg / m ^{3 of} cement. An agent, 0.22 kg / m ³ antifoaming agent and 246 kg / m ³ water (water cement ratio 45.0%) were added and kneaded.
(3) Using the flow cone of the physical test method of JIS R 5201 cement, the mortar prepared in (2) was filled into a flow cone having a diameter of 100 mm and a height of 40 mm, the cone was pulled out, and the mortar flow was measured.

(Test results)
The mortar flow measurement results are shown in Table 8.

  From the results shown in Table 8, in the mixed sands 1 and 2, a good mortar flow was obtained. In the mixed sand 4, since particles having a small particle diameter are closely packed, the mixed sand 4 is so hard that kneading is difficult, and no mortar flow was observed. Although a little mortar flow was seen in the mixed sand 3 and details are not shown, when the water-cement ratio was increased to 50%, the mortar flow increased to 130 mm, but separation of the aggregate and the cement paste occurred. As described above, by limiting the particle size distribution of the heavy fine aggregate and passing through a sieve having a size of 0.15 mm so that the mass percentage of the total particles is 20% or less, the mortar flow is remarkably remarkable. It became clear that a good effect was obtained.

Example 4
(Test method)
(1) A hot scarf with a surface dry density of 5.08 g / cm ³ and spherical particles of about 75%, and a granular pig iron with a surface dry density of 5.60 g / cm ³ and spherical particles of about 54% (from blast furnace granulated slag 1) were mixed as appropriate, and mixed sands 5 to 10 having a particle size distribution shown in Table 4 were prepared. (Mixed volume ratio of mixed sand 7; hot scarf 70: granular pig iron 30)
(2) Ordinary Portland cement is mixed with the mixed sand prepared in (1) at a sand cement volume ratio of 3.19, and 5.46 kg / m ³ of polycarboxylic acid ether-based high-performance AE water reduction per 547 kg / m ^{3 of} cement. An agent, 0.22 kg / m ³ antifoaming agent and 246 kg / m ³ water (water cement ratio 45.0%) were added and kneaded.
(3) In the same manner as in Example 3, the mortar flow was measured.
(Test results)
Table 9 shows the measurement results of the mortar flow.

  From the results shown in Table 9, in the mixed sands 5, 6 and 7, a good mortar flow was obtained. Compared with this, in the mixed sands 8, 9 and 10, the fluidity of the mortar was clearly lowered. In the mixed sands 9 and 10, the aggregate and the cement paste were slightly separated. As described above, by restricting the particle size distribution of the heavy fine aggregate and passing through a sieve having a size of 0.15 mm so that the percentage by mass of the total particle is 10% or more, the mortar flow is remarkably remarkable. It became clear that a good effect was obtained.

Example 5
(Test method)
(1) A hot scarf having a surface dry density of 5.08 g / cm ³ and spherical particles of about 75%, a mill scale composed of a surface dry density of 4.95 g / cm ³ and flat particles are mixed in various volume ratios. The mixed sands 11 to 18 were prepared.
(2) Ordinary Portland cement is mixed with the mixed sand prepared in (1) at a sand cement volume ratio of 2.68, and 5.84 kg / m ³ of polycarboxylic acid ether-based high-performance AE water reduction per 584 kg / m ^{3 of} cement. agent and, in addition a defoaming agent 0.23 kg / ^{m 3,} of 292kg / ^{m 3} water (water-cement ratio 50.0%), and kneaded.
(3) In the same manner as in Example 3, the mortar flow was measured. Moreover, the unit volume mass of the mortar was measured.

(Test results)
The measurement result of the mortar flow using the mixed sands 11 to 18 is shown in FIG. 3, and the unit volume mass of the mortar using the mixed sands 11 to 18 is shown in FIG.

  When the mixing ratio of the hot scarf (HS) and the mill scale (MS) was 20:80, almost no mortar flow was observed, and separation of the aggregate and the cement paste was observed. When the mixing ratio of the hot scarf was high from 30:70, a good mortar flow was obtained. At this time, the ratio of the spherical particles was 20% or more.

  When the mixing ratio of the hot scarf and the mill scale is 40:60 and the mixing ratio of the hot scarf is high, the unit volume mass of the mortar is remarkably high, which is more preferable. At this time, the ratio of the spherical particles was 25% or more.

Example 6
(Test method)
(1) Mill scale composed of surface dry density 4.95 g / cm ³ , flat particles, converter dust coarse fraction (coarse dust) with surface dry density 5.84 g / cm ³ and spherical particles of about 73% ), And a dry density of 5.60 g / cm ³ and granular pig iron of about 54% spherical particles (separated magnetically separated from blast furnace granulated slag during the pulverization process) by mass percentage of 30 to 80%, 0 to 60%, And it mixed in the ratio of 0-60%, and mixed sand was prepared.
(2) Ordinary Portland cement is mixed with the mixed sand prepared in (1) at a sand cement volume ratio of 2.68, and 5.84 kg / m ³ of polycarboxylic acid ether-based high-performance AE water reduction per 584 kg / m ^{3 of} cement. agent and, in addition a defoaming agent 0.23 kg / ^{m 3,} of 292kg / ^{m 3} water (water-cement ratio 50.0%), and kneaded.
(3) In the same manner as in Example 3, the mortar flow was measured.

(Test results)
The mortar flow measurement results are shown in Table 10. The determination of the mortar flow was good at 130 mm or more.

Example 7
(Test method)
(1) The mill scale, the converter dust coarse particles, and the granular pig iron were mixed at a mass percentage of 0 to 30%, 10 to 60%, and 10 to 70%, respectively, to prepare mixed sand.
(2) Ordinary Portland cement is mixed with the mixed sand prepared in (1) at a sand cement volume ratio of 3.19, and 5.46 kg / m ³ of polycarboxylic acid ether-based high-performance AE water reduction per 547 kg / m ^{3 of} cement. An agent, 0.22 kg / m ³ antifoaming agent and 246 kg / m ³ water (water cement ratio 45.0%) were added and kneaded.
(3) In the same manner as in Example 3, the mortar flow was measured.

(Test results)
The mortar flow measurement results are shown in Table 11. The determination of the mortar flow was good at 130 mm or more.

  In general, when the water-cement ratio is high, the flowability of the mortar increases, but the cement paste and the aggregate are easily separated. When the water-cement ratio is low, the cement paste and the aggregate are separated. Although it becomes difficult, the fluidity of the mortar becomes low. On the other hand, the higher the mixing ratio of the mill scale, the lower the fluidity, and the higher the mixing ratio of the granular pig iron, the more likely the separation of the cement paste and the aggregate tends to occur. The mixing ratio of the scale was 30% or more and the water cement ratio was 50.0%. In Example 7, the mixing ratio of the mill scale was 30% or less and the water cement ratio was 45.0%.

  From the results shown in Table 10 and Table 11, as the fine aggregate used in the weight mortar in the method for producing a counterweight of the present invention, the mixing ratio of mill scale, converter dust coarse fraction, and granular pig iron is respectively It is clear that the mass percentage is preferably 0 to 70%, 0 to 50%, and 0 to 60%, particularly preferably 20 to 70%, 20 to 50%, and 0 to 40%. It was.

In addition, when the mixing ratio of mill scale, converter dust coarse particles, and granular pig iron is 0 to 70%, 0 to 50%, and 0 to 60% in mass percentage, the heavy fine aggregate is the main Containing at least one of FeO, Fe ₂ O ₃ , and metallic iron as a constituent component, spherical particles out of all particles are 20% or more, and particles passing through a sieve having a nominal size of 0.15 mm are in mass percentage of all particles. The particles passing through a sieve having a size of 10% to 20% and a nominal size of 1.2 mm satisfied the requirements of 70% to 90% in terms of mass percentage of the total particles. Furthermore, the particle size distribution of the heavy fine aggregate in the method for producing a counterweight of the present invention shown in Table 1 was satisfied over the entire particle size range.

<Examples of counterweight production and comparative production by the prepacked method>
A mortar injection tube and an inspection tube were installed inside the counterweight mold, and heavy coarse aggregate was introduced. As the heavy coarse aggregate, “artificial stone manufactured by mixing dust generated in the steelmaking process and powdered reduced slag, heating and melting and solidifying by cooling” was used. There, the mortar prepared in Example 1 and Example 2 was used as an injection mortar and injected without applying vibration.

  The mortar prepared in Example 1 and Example 2 can be uniformly injected into the gap of the coarse aggregate in the counterweight mold without applying vibration by the prepacked method, and the counter with high density. Weight was obtained.

  On the other hand, the mortar prepared in the comparative example had a high bleeding rate and could not be used because of easy material separation. Although the amount of water was reduced from here, the fluidity became small, and the prepacked construction method could not be uniformly injected into the coarse aggregate voids in the counterweight mold without vibration.

  Mixed sand 1-2 of Example 3, mixed sand 5-7 of Example 4, and mixed ratio of hot scarf (HS) and mill scale (MS) from 30:70 in Example 5 is high. The weight mortar using the heavy fine aggregate, the heavy fine aggregate having a mortar flow of 130 mm or more in Example 6 and Example 7, both considering the fluidity and mortar flow measured above, It is clear that the injection mortar can be uniformly injected even into the gap of the coarse aggregate in the counterweight mold without applying vibration, and a high-density counterweight can be obtained.

  On the other hand, the mixing ratio of the hot scarf from 20:80 in the mixing sand 3-4 of Example 3, the mixing sand 8-10 of Example 4, and the mixing ratio of hot scarf (HS) and mill scale (MS) in Example 5 The weight mortar using the low weight heavy aggregate, the weight fine aggregate having a mortar flow of less than 130 mm in Example 6 and Example 7, is prepacked construction method in view of the measured fluidity and mortar flow. Thus, it is clear that the injection mortar cannot be uniformly injected even into the coarse aggregate voids in the counterweight mold without applying vibration, and a dense counterweight cannot be obtained.

  The counterweight manufactured by the method for manufacturing a counterweight of the present invention can be poured into a mold for a counterweight without a gap, and is excellent in simplification of work, safety, noise prevention, etc. Are widely used in the field of construction machines such as excavators, cranes and forklifts.

It is the figure which showed the counterweight of the shovel. It is the figure which showed the counterweight (front side whole surface) of the hoist. It is the figure which showed the relationship between the mixing ratio of a hot scarf (HS) and a mill scale (MS), and mortar flow. (Example 5) It is the figure which showed the relationship between the mixing ratio of a hot scarf (HS) and a mill scale (MS), and the unit volume mass of mortar. (Example 5)

Claims (12)

A method for producing a counterweight in which a coarse aggregate is filled in advance and mortar is injected into a gap between the coarse aggregates, and the heavy fine aggregate contained in the mortar includes FeO and Fe ₂ as main constituent components. An aggregate containing at least one of O ₃ and metallic iron, wherein spherical particles out of all particles are 20% or more, and particles passing through a sieve having a nominal size of 0.15 mm are 10% by mass of all particles. A method for producing a counterweight, characterized in that the weight is fine aggregate of 20%.   The above-mentioned heavy fine aggregate is a heavy fine aggregate obtained by mixing recycled materials generated in the steelmaking process, and particles passing through a sieve having a nominal size of 1.2 mm have a mass percentage of 70% or less of all particles. The method for producing a counterweight according to claim 1, which is 90%.   The method for producing a counterweight according to claim 1 or 2, wherein the heavy fine aggregate contains a hot scarf that is generated in a hot-melt processing step of a steel slab surface.   The above-mentioned heavy fine aggregate is selected from mill scale generated in the steelmaking rolling process, coarse particles screened with a particle size of 50 μm from steelmaking converter dust, and granular pig iron separated from blast furnace granulated slag The method for producing a counterweight according to claim 3, wherein the counterweight is obtained by mixing at least one kind of a hot scarf.   The method of manufacturing a counterweight according to any one of claims 1 to 4, wherein the heavy fine aggregate contains a mill scale generated in a steelmaking rolling process.   The counter according to any one of claims 1 to 5, wherein the heavy fine aggregate is obtained by mixing a hot scarf and a mill scale in a mixing volume ratio of 100: 0 to 30:70. Weight manufacturing method.   The above-mentioned heavy fine aggregate is obtained by mixing a hot scarf and a coarse particle portion screened with a particle size of 50 μm in a steelmaking converter dust in a mixing volume ratio of 100: 0 to 70:30. The method for manufacturing a counterweight according to any one of claims 1 to 4.   The weight fine aggregate is obtained by mixing a hot scarf and granular pig iron separated from granulated blast furnace slag in a mixing volume ratio of 100: 0 to 70:30. A method of manufacturing a counterweight according to any one of the claims.   The above-mentioned heavy fine aggregate is selected from mill scale generated in the steelmaking rolling process, coarse particles screened with a particle size of 50 μm from steelmaking converter dust, and granular pig iron separated from blast furnace granulated slag The method for producing a counterweight according to claim 1 or 2, wherein the counterweight is obtained by mixing at least two kinds.   The said fine fine aggregate is 20-70%, 20-50%, and 0-40% in the mixing percentage of the said mill scale, the converter dust coarse particle part, and granular pig iron, respectively. A method for producing a counterweight as described in 1.   The counterweight according to any one of claims 1 to 10, wherein the coarse aggregate is a heavy coarse aggregate containing an artificial stone produced by melting a resource containing dust generated in a steelmaking process. Manufacturing method.   A counterweight manufactured using the method for manufacturing a counterweight according to any one of claims 1 to 10.

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