JPS62248607A - Manufacture of ready-mixed concrete - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (A) Field of Industrial Application The present invention relates to a method for producing ready-mixed concrete, particularly when the maximum aggregate size is 80 m/m or 150 m/m.
The present invention relates to a method for manufacturing dam concrete using gravel with a large aggregate diameter of 1.2 m.

(b) Conventional technology dam concrete has a maximum aggregate size of 80 m/m,
Alternatively, since gravel with a large aggregate diameter of 150 m/m is used, a gravity mixer has been mainly used as a conventional kneading machine. Recently, twin-screw forced mixers, which mix materials uniformly in a short period of time to produce high-quality concrete, have been gradually adopted.

(c) Problems that the invention seeks to solve Forced mixers have good mixing efficiency because they forcefully mix the materials with rotating mixing blades, but they are difficult to mix with dam concrete that uses hard mixing and gravel with a large aggregate diameter. When mixing, there is a drawback that the parts of the mixer are seriously damaged and the power required is large.

In addition, gravity mixers rotate the drum and mix the ingredients using their own weight, so there is less mechanical damage compared to forced mixers, but it takes 2 to 30 minutes to mix evenly.
It requires 3 minutes of kneading time and has the disadvantage of poor kneading efficiency.

In view of the above points, the present invention proposes a method for producing high-quality dam concrete in a short time with little mechanical damage by taking advantage of the respective characteristics of forced mixers and gravity mixers.

(d) Means for solving the problems The present invention uses a forced mixer 1 as a first kneading mechanism,
A gravity mixer 2 is used as the second kneading mechanism, and the first
Sand, cement, water, and gravel with a small aggregate diameter are put into the second kneading mechanism and mixed for a predetermined period of time to create ready-mixed concrete that will become the base. Large gravel is added and mixed.

(E) Function When producing dam confut according to the present invention, sand, cement, water, and gravel with a small aggregate diameter are sequentially charged into the forced mixer 1, which is the first kneading mechanism, to achieve efficient production in a short time. Mix well to make ready-mixed concrete as a base0
Next, the mixed ready-mixed concrete is put into the gravity mixer 2 of the second mixing mechanism, and at the same time gravel with a large aggregate diameter is put in and kneaded to obtain ready-mixed concrete of a desired mix.

(f) Example In the present invention, multiple kneading mechanisms are used.

1 is a two-car forced mixer which is a first kneading mechanism, in which a pair of kneading shafts are rotatably supported in opposite directions in a kneading tank, and an appropriate number of arms are arranged radially around the kneading shaft. A kneading blade having an appropriate angle is attached to the tip of the arm.

Reference numeral 2 denotes a gravity mixer as a second kneading mechanism, which mixes the materials by their own weight while rotating the drum 4 with a drive motor 3, and tilts the drum 4 by extending the cylinder 5 to discharge the materials.

Figure 1 shows a system in which two gravity mixers are installed to increase the productivity of ready-mixed concrete.

Figure 2 is a diagram of the mixing cycle time (in the case of one gravity mixer), and to explain the manufacturing method of dam concrete with reference to this diagram, first, each material is mixed based on the desired mix. Weigh. Water in water measuring tank 6, cement in cement measuring tank 7, sand in sand measuring tank 8, gravel 20 m/m or less in gravel measuring tank 9, gravel 20 m/m
m to 40 m/m or less in gravel measuring tank 10, gravel 40 m/m
m / m to 80 m / m or less in gravel measuring tank 11
Then, the gravel from 80 m/m to 150 m/m or less is measured in the gravel measuring tank 12. Measured amounts of sand, water, cement, and gravel with a relatively small aggregate diameter, here 40 m/m or less, are sequentially charged into a two-shaft forced mixer l, which is a first kneading mechanism. In addition, gravel with a large aggregate diameter is temporarily stored in the hopper 13.
and prepare for the next weighing.

The materials put into the two-wheel forced mixer 1 are kneaded for a predetermined period of time to create ready-mixed concrete that will serve as the base.

Because gravel with a large aggregate diameter is not put into this two-shaft forced mixer 1, the advantages of a forced mixer are utilized.
Uniform ready-mixed concrete can be produced in a short time Next, the mixed material mixed in the twin-screw forced mixer 1 is fed into the gravity mixer 2 through the chute 14, and at the same time, the large-diameter aggregates stored in the temporary storage hopper 13 are mixed. Add gravel and mix for a specified period of time. In the kneading in the gravity mixer 1, gravel with a large aggregate diameter is mixed with the ready-mixed concrete that has already been kneaded in the twin-screw forced mixer, so the kneading time is short.

Thereafter, the same operation is repeated, but as shown in the time cycle diagram, kneading is performed simultaneously in the forced mixer and the gravity mixer, and one cycle actually takes about 70 seconds.

(G) Effect The present invention mixes cement, sand, water, and gravel with a small aggregate diameter in a forced mixer l, which is a first mixing mechanism, to knead ready-mixed concrete as a base, and mixes this ready-mixed concrete into a first mixer. Since it is put into the gravity mixer 2, which is the mixing mechanism of 2, and mixed with gravel with a large aggregate diameter, the characteristics of each mixer are utilized, and uniform ready-mixed concrete can be produced in a short and efficient manner. It also has the practical benefit of minimizing damage to the mixer mechanism.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of an apparatus for carrying out the invention, and FIG. 2 is a chart of cycle times.

Claims (1)

[Claims] A forced mixer is used as the first kneading mechanism, and a gravity mixer is used as the second kneading mechanism. Sand, cement, water, and gravel with a small aggregate diameter are charged into the first kneading mechanism, and after being kneaded for a predetermined time. . A method for producing ready-mixed concrete, characterized in that, at the same time as the kneaded material is introduced into a second mixing mechanism, gravel having a large aggregate diameter is introduced and kneaded.