JPH0574443B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] This invention relates to a method for producing cooled concrete.

[Conventional technology and its problems]

In general, temperature has a large effect on the strength of concrete. For example, if the difference between the internal and external temperatures of concrete is large, cracks will occur, and if the temperature after pouring is high, the strength of concrete will be affected. is known to significantly reduce For this reason, cooled concrete has traditionally been widely used when concrete is poured under high temperatures such as during summer.

By the way, the above-mentioned chilled concrete has conventionally been produced by adding ice in a mixer or blowing cooling gas and mixing it with concrete materials, but not only is the cooling efficiency extremely low, but the cooling etc., and the cooling was likely to be uneven.
Furthermore, since the concrete materials were mixed all at once, the degree of dispersion of the cement particles was also very low.

The present invention aims to solve the conventional problems at once and provide a method for producing cooled concrete that can be efficiently and uniformly cooled and that has an extremely good degree of dispersion of cement particles.

[Means for solving problems]

That is, the present invention includes a step of adding cement and water to a paste mixer and then kneading them while blowing cooling gas to produce a cement paste, and a step of adding the cement paste to aggregate and kneading it again. It depends on this.

[Effect]

By blowing cooling gas into a paste mixer that is more airtight than conventional mixers, it cools efficiently and uniformly to produce concrete paste, which is then added to aggregate and mixed again. This makes it possible to produce uniformly cooled concrete with high viscosity and separation resistivity.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

Reference numeral 1 denotes a rectangular parallelepiped steel frame with a mixer pedestal 2 therein, 3 a paste mixer installed on the pedestal 2, and the paste mixer 3 is constructed as shown in FIG. .

That is, in the figure, 4 is a cylindrical mixing drum, 5 is a screw horizontally disposed inside the mixing drum 4, and the screw 5 is provided with spiral blades symmetrically so that it can be drawn inward from both ends. It is assumed that a transfer thrust is generated toward the 6 is a shaft of the screw 5; 7 is a vane plate attached to the center of the shaft 6 that generates a downward thrust; 8;
is a reflux chamber formed on the lower surface of the mixing drum 4, 9 and 10 are three openings that communicate the reflux chamber 8 and the mixing drum 4, and 11 is a reflux chamber formed along the central opening 9 in the reflux chamber 8. 12 is a tapered narrow passage formed downward in 11 of the narrow passage.
A reflux passage is branched and communicates with the openings 10 at both ends from the tip of the reflux chamber 8, and 13 is a wide rotary gate attached to the bottom of the reflux chamber 8.
The rotary gate 13 functions as a paste discharger and as a paste collision body. Reference numeral 14 denotes a short inner cylinder with a small diameter that is concentrically inserted into one end of the mixing drum 4, and the shaft 6 passes through the inner cylinder 14, and a spiral small-diameter blade is attached to the shaft 6. As a result, the transfer screw 15 generates an inward transfer thrust. 16 is the inner cylinder 14
A cement supply port 17 is formed on the top wall of the mixing drum 4 located above the tip of the inner cylinder 14, and a water supply port 18 is formed on the side wall of the reflux chamber 8. This is the inlet for cooling gas.

Reference numeral 19 denotes a two-shaft forced kneading mixer located below the paste mixer 3 and installed on the pedestal 2 in the frame 1. The two-shaft forced kneading mixer 19 is a third
As shown in the figure, two drive shafts 21 that rotate in opposite directions are horizontally arranged in a mixing drum 20 in parallel, and arm-shaped stirring blades 22 are attached to each of the drive shafts 21 alternately. In addition, a gate 23 is provided on the bottom wall of the mixing drum 20. The cement supply port 16 of the paste mixer 3 is connected to a cement meter through a chute 24, and the water supply port 17 is connected to a water meter through a pipe. Further, an aggregate measuring device is connected to the biaxial forced mixing mixer 16 via a chute 25. 26 is a hopper disposed at the bottom of the biaxial forced mixing mixer 19.

Next, the production of cooled concrete using the above apparatus will be explained.

First, after measuring the required amount of water with a water meter and the required amount of cement with a cement meter, they are simultaneously supplied into the mixing drum 4 while operating the paste mixer 3. Further, a cooling gas such as nitrogen gas is blown into the mixing drum 4 from the blowing port 18 . Then, as shown in FIG. 2, the water scatters and falls into the mixing drum 4 by the screw 5, and the cement falls into the inner cylinder 14 and then scatters and falls into the mixing drum 4 by the transfer screw 15. It will be done. The water and cement that have scattered and fallen into the mixing drum 4 are sequentially forced into the center by the screw 5 and dispersed into particles by the compression and shearing action generated in the center. Then, by the action of the vanes 7, the fluid is forced into the narrow passage 11 to increase the flow velocity, and its discharge force causes it to collide with the inner wall surface of the rotary gate 13. The paste, whose particles have been highly dispersed through collision, branches off one after another with the cooling gas, and each branch into the reflux passage 1 while being cooled.
2 and is returned to the mixing drum 4 through the openings 10 at both ends. At this time, the cooling gas refluxes and comes into contact with the paste, thereby efficiently cooling the paste. Thereafter, the reflux chamber 8 and the mixing drum 4 are refluxed with cooling gas, and the mixture is kneaded while being directly cooled by the cooling gas to produce a cooled cement paste.

On the other hand, the aggregate weighed using a measuring device is put into the two-screw forced mixing mixer 19 and mixed in the dry state.

Thereafter, the rotary gate 13 of the paste mixer 3 is opened and the generated cooled cement paste is introduced into the biaxial forced mixing mixer 19, and the cooled cement paste and aggregate are mixed into the biaxial forced mixing mixer 1.
Step 9 is also kneaded to obtain the required cooled concrete.

Note that the paste mixer 3 shown in the above device
The structure of is not limited to this, and other known paste mixers may be employed. Also,
Of course, the object of the present invention can also be achieved by using a single-shaft mixer or other mixer instead of the two-shaft forced kneading mixer 19.

〔Effect of the invention〕

Since this invention is configured as described above, cooling gas is blown into the paste mixer 3, which is more airtight than conventional mixers, to efficiently and uniformly cool the paste mixer 3 to produce cement paste. Moreover, since uniformly cooled cement paste and aggregate are re-kneaded in the mixer 19, uniformly cooled concrete with high viscosity and separation resistance can be obtained.

[Brief explanation of drawings]

The drawings show one example of an apparatus for carrying out the present invention, and FIG. 1 is a partially cutaway side view, FIG. 2 is a vertical sectional view showing a paste mixer 3, and FIG.
The figure is a cross-sectional view showing a biaxial forced kneading mixer 19. 3...Mixer for paste, 19...Two-screw forced kneading mixer.

Claims (1)

[Claims] 1 The process consists of a process of putting cement and water into a paste mixer and then kneading them while blowing cooling gas to produce cement paste, and a process of adding the cement paste to aggregate and kneading it again. Features: A method for producing cooled concrete.