JPH0768516A - Heavy concrete manufacturing method - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a method for producing heavy concrete by utilizing the characteristics of heavy concrete material, which can easily obtain high quality products without requiring special equipment or work. [Structure] First, a predetermined amount of highly fluid mortar 2 having a water cement ratio of 50% or less and a flow value of 70 cm or more is injected into a mold 1, and subsequently, as a weight aggregate 3, a specific gravity of 3.5 or more, Iron ore with a particle size of 5 to 60 mm, a maximum and minimum particle size difference of 20 mm or less, and a porosity of 35% or more is charged into the mold 1, and the weight aggregate 3 that is charged is settled in the mortar 2 and uniformly dispersed. To do. After curing, the mold is removed and the heavy concrete block 4 is carried out.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing heavy concrete.

[0002]

2. Description of the Related Art Heavy concrete is concrete in which the unit volume weight of concrete is increased by using heavy aggregate having a specific gravity higher than that of normal aggregate. It is used for radiation shielding concrete, wave-dissipating blocks, and seawalls. It is used as concrete and concrete for foundation of heavy machinery. As the heavy aggregate, an artificial heavy aggregate such as iron or, as a cheaper one, a naturally occurring heavy aggregate such as magnetite, hematite, sand iron, etc. is used. The problem with heavy concrete is material separation, and if a high specific gravity material such as iron ore is used as the aggregate to increase the specific gravity of the heavy concrete, the aggregate will be However, depending on its particle size and specific gravity, it settles and causes a material separation phenomenon. On the other hand, Japanese Patent Application Laid-Open No. 63-239140 discloses a mixture of heavy concrete in which a predetermined amount of an organic polymer dispersion is mixed to reduce the amount of unit water without impairing workability and suppress breathing and material separation. It is shown. In addition, JP-A 1-3
In JP-A-01549 and JP-A-1-301551, iron oxide ore is used as coarse aggregate, sand iron is used as fine aggregate, and a predetermined amount of silica fine particles of ultrafine particles is mixed as an admixture to suppress material separation. At the same time, a heavy concrete mix with improved durability against the chemical action of seawater is disclosed. Further, in Japanese Patent Laid-Open No. 1-301549, iron oxide ore is used as a coarse aggregate, sand iron is used as a fine aggregate, and a predetermined amount of superfine powder granulated slag is mixed to obtain the same effect of heavy concrete. The formulation is shown. Regarding the production or supply of heavy concrete, a concrete plant kneading method is generally used in which what is produced in a concrete plant is carried into the site as ready-mixed concrete. In addition, there is a pre-packed concrete method in which coarse aggregate with a grain size adjusted in advance is pre-filled in a construction site and mortar is injected later, which is often used for underwater construction and the like.

[0003]

In the case of the concrete plant kneading method, heavy aggregate such as iron ore is brought into the concrete plant, and a stockyard and a storage tank for it are required. In addition, when using iron ore, it is necessary to take measures against iron ore dust and wastewater treatment. Also,
In the case of heavy concrete, if heavy aggregate is put into a mixer and kneaded, the mixer will be greatly worn out and power consumption will be increased. Further, there is a problem that when the concrete is poured, the materials are likely to be separated from each other, resulting in a non-uniform concrete. On the other hand, the prepacked concrete method has great advantages in underwater construction, but it is not always easy to obtain high-quality concrete in the construction of ordinary heavy concrete. In addition, it is difficult for mortar to invade into the heavy aggregate such as iron ore packed in advance, which is troublesome to manage. Furthermore, since the mortar is usually filled from the bottom, the equipment and work are complicated. The present invention solves the problems in the conventional techniques as described above by utilizing the characteristics of heavy concrete material,
It is intended to provide a method for producing heavy concrete which can easily obtain a high-quality product without requiring special equipment or work.

[0004]

The method for producing heavy concrete according to the present invention utilizes a difference in specific gravity between heavy mortar 3 such as iron ore and mortar to cause heavy gravel 3 to settle in mortar 2.
The concrete is solidified by solidification, and mortar having fluidity is previously poured into the mold, and then the heavy aggregate is put into the mold. Water cement ratio of mortar is 50%
The following is preferable. The reason is to improve the material separation resistance of the mortar itself and to utilize the characteristics of the aggregate with high specific gravity in heavy concrete. The coarse aggregate constituting the heavy aggregate has a specific gravity of 3.5 or more, a particle size of 5 to 60 mm, a maximum and minimum particle size difference of 20 mm or less, and a porosity of 35%.
The above is preferable. As such a heavy aggregate,
Usually, iron ore is used, and a single-grain iron ore or the like having a grain size of 5 to 60 mm and a grain size difference adjusted to 20 mm or less is suitable. When iron ore is used, the specific gravity of heavy concrete can be easily changed with the same iron ore by adjusting the particle size distribution and changing the porosity. It is also possible to mix and feed iron ores with different specific gravities. The heavy aggregate is not necessarily limited to iron ore, and artificial heavy aggregate such as iron may be used in some cases. Regarding the mortar, in the present invention, since the heavy aggregate is settled in the mortar by utilizing the difference in specific gravity between the heavy aggregate and the mortar, it is desirable to use a mortar having a flow value of 70 cm or more. The flow value mentioned here is a value obtained by measuring the spread in the horizontal direction when the slump cone used in the slump test is packed with mortar and the slump cone is pulled up on a flat plate (unit: cm). In order to secure fluidity of 70 cm or more while maintaining a water-cement ratio of 50% or less, for example, a water-reducing agent, a high-performance water-reducing agent or a fluidizing agent may be added as an admixture in the composition design, or a particle size may be used as an admixture. There is a method of adding adjusted blast furnace slag fine powder, fly ash, and the like. In addition, flow value 70cm or more, water cement ratio 50
As long as natural sand is used as an aggregate, a mortar of less than 5% has a specific gravity of about 2.5 or less and an extremely small viscosity. This mortar has a specific gravity of 3.5 or more and a particle size of 5
If the weight aggregate with a porosity of 35% or more is used from the top, there is a difference of 1 or more in specific gravity from the mortar, and gravity settles,
Moreover, since aggregates having a particle size of 5 mm or more have a single particle size, there is no difference in the sedimentation speed, and a homogeneous heavy concrete can be formed. Further, at this time, by vibrating and compacting by using a form vibrator or the like, it is possible to further ensure uniform dispersion of the heavy aggregate. The specific gravity of the heavy aggregate as coarse aggregate is 3.5 or less, and the particle size is 5 mm (90 mm
If it is less than or equal to (%), the sedimentation rate by gravity is small and it is difficult to form a homogeneous heavy concrete.

[0005]

1 to 5 show an embodiment in which the method for producing heavy concrete of the present invention is applied to the production of a heavy concrete block, and the work is performed in the following procedure.

(1) Formwork Assembly (See FIG. 1) The formwork 1 is preferably a watertight formwork in which mortar does not leak out,
Assemble a mold, such as metal foam, which is strong enough to withstand the loading of the heavy aggregate 3.

(2) Mortar injection (see FIG. 2) A mortar 2 having a predetermined specific gravity and fluidity in which the heavy aggregate 3 easily sinks is blended and designed, and injected into the mold 1. In addition, it is desirable to mix a retarder as an admixture so that the setting time of the mortar 2 becomes long.

(3) Completion of injection of mortar (see FIG. 3) Prior to the introduction of the heavy aggregate 3, the required amount of mortar 2 obtained by calculation or experiment is injected into the mold 1.

(4) Heavy Aggregate Input (See FIG. 4) Iron ore as heavy aggregate (coarse aggregate) 3 is immediately added without waiting time. By blending and designing the mortar 2 and the heavy aggregate 3 so as to be within the predetermined range of the present invention, the introduced heavy aggregate 3 sinks into the mortar 2 and is uniformly dispersed. At this time, by using vibration compaction together,
The effect can be increased. In addition, if the particle size of the heavy aggregate 3 is not uniform, the coarse aggregate will settle down quickly, and it will be unevenly distributed in the lower part.

(5) Completion of loading of the heavy aggregate (see FIG. 5) When the loading of the iron ore as the heavy aggregate 3 is completed, the finishing press is performed from the upper part, and finally the mortar lacking is filled with the form 1
Add additional injection on top. After performing the required curing, demolding,
It is carried out as a concrete block 4.

[0011]

According to the manufacturing method of the present invention, without bringing the heavy aggregate 3 such as iron ore into the concrete plant, only the mortar is supplied from the concrete plant to the site, and the heavy aggregate 3 is contained therein. Heavy concrete can be easily manufactured simply by throwing it in. In addition, the production method of the present invention does not require special equipment or work, and can easily produce homogeneous and high-quality heavy concrete.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional side view showing a box-shaped mold.

FIG. 2 is a vertical cross-sectional side view showing a state where mortar is poured into a box-shaped mold.

FIG. 3 is a vertical cross-sectional side view showing a state where injection of mortar into a box-shaped mold has been completed.

FIG. 4 is a vertical cross-sectional side view showing a state in which heavy aggregate is being supplied into a mold into which mortar has been injected.

FIG. 5 is a vertical cross-sectional side view showing a state in which a predetermined amount of mortar and heavy aggregate have been fed into the frame.

[Explanation of symbols]

 1 Formwork 2 Mortar 3 Heavy aggregate 4 Heavy concrete block

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Claims (5)

[Claims] 1. A method for producing a heavy concrete using heavy aggregate, wherein after pouring mortar 2 having fluidity into mold 1 in advance, heavy aggregate 3 is charged into said mold 1, A method for producing heavy concrete, which comprises forming concrete by allowing it to settle in mortar 2. 2. The method for producing heavy concrete according to claim 1, wherein the mortar is a mortar having a water cement ratio of 50% or less. 3. The method for producing heavy concrete according to claim 2, wherein the mortar is a mortar having a flow value of 70 cm or more and having fluidity. 4. A coarse aggregate having a specific gravity of 3.5 or more and a particle size of 5 to 5.
The method for producing heavy concrete according to claim 1, 2 or 3, wherein a heavy aggregate having a diameter of 60 mm, a maximum / minimum particle size difference of 20 mm or less, and a porosity of 35% or more is used. 5. The method for producing heavy concrete according to claim 1, 2, 3 or 4, wherein vibration compaction is performed after the addition of the heavy aggregate.