JPS59224310A - Manufacture of centrifugal force molding concrete product - Google Patents

Abstract

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

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a high-strength centrifugally formed concrete product by kneading concrete materials, centrifugally forming them, and curing them in high temperature day pressure steam.

High-strength centrifugally formed concrete products are usually made using siliceous powder, centrifugally compacted, and then cured using crepe curing to achieve a compressive strength of approximately SOO to 1. o o o Kr/d. Among these high-strength centrifugally formed concrete products, construction piles in particular are currently produced in large quantities.

Conventionally, in the process of manufacturing this type of high-strength centrifugally formed concrete piles, the method of kneading concrete materials was to add other materials, excluding chemical admixtures, to a mixer almost simultaneously and mix them at the same time. After that, a chemical admixture is added and kneaded for a while to form a kneaded dough.

Recently, various methods have been tried regarding the order of adding concrete materials. There are also known methods that aim to reduce breathing.

However, the disadvantages of the high-strength centrifugally formed concrete products obtained by these methods are: l) Due to the difference in specific gravity of the concrete materials and the size of the particles, rearrangements within the coiclete structure caused by centrifugal force may cause , material separation is likely to occur.

2) Due to the reason in 1) above, the strength of the obtained product is often uneven.

The present inventor has focused on the fact that the effect of adding siliceous powder due to material separation phenomenon is not always fully expressed, and has made efforts to find ways to utilize siliceous powder to further increase its high strength effect. As a result of the research, a mixed powder consisting of cement and siliceous powder was gradually added to the aggregate whose interior had been saturated with water, and the mixture was mixed and stirred to cause a granulation phenomenon. The present invention was achieved by discovering that by adding the remaining blended water and chemical admixtures and kneading the paste again after the presence of the paste, the compressive strength can be increased compared to the conventional method.

That is, the present invention has the following features: 1. Fine aggregate and coarse aggregate having surface water are mixed in advance, and a mixed powder consisting of a hydraulic substance such as cement or gypsum and siliceous powder is gradually added thereto. A centrifugally formed concrete product characterized by carrying out an empty wire sieving process to mix and stir the mixture, and then re-kneading the remaining blended water and chemical admixtures with weight, centrifugally forming the mixture, and then curing it with high-temperature and high-pressure steam. manufacturing method.

2. The method for producing a centrifugally formed concrete product according to claim 1, wherein the mixed powder has a ratio of siliceous powder to cement in a range of 5 to 40 cm. .

This is a method for producing a centrifugally formed concrete product characterized by the following.

The granulation phenomenon referred to in the present invention is an application of conventional granulation theory. As a cohesive function of powder materials, when the liquid content of the powder increases, the stirring and mixing energy of the wet powder material increases, and at a certain liquid content, the solid particles are filled with liquid. It is known that it takes a form called a so-called funicular to capillary region. Therefore,
When the aggregate is hydrated, a mixture of siliceous powder that acts effectively on cement is added and evenly dispersed in a hydrothermal reaction, and the mixture is mixed and stirred, a wet powder of cement, siliceous powder, and water is formed. A large number of bodies exist around the aggregate, and a phenomenon can be seen as if they were coating the surface of the aggregate. Moreover, after this, the remaining mixed water and chemical admixture were added and kneaded again, and when the mixed concrete was observed, it was found that the siliceous powder was not mixed with the siliceous powder due to breathing like concrete obtained by the conventional kneading and mixing method. Almost no floating spots were observed.

The concrete obtained in this way is centrifugally formed,
Surprisingly, it has been found that when the material is subjected to atmospheric pressure steam curing followed by farm temperature high pressure steam curing using an autoclave, the rate of increase in compressive strength is further improved compared to the conventional method.

Furthermore, when comparing the compressive strength of a molded product with no addition of siliceous powder and under the same curing conditions as the above-mentioned cross-wire method, it was found that the effect of adding siliceous powder was extremely high compared to the conventional method.

Therefore, when obtaining concrete with a predetermined compressive strength, it has been found that the amount of cement per unit can be reduced compared to the conventional method, and this has led to the invention.

As for the properties of the aggregate used in the present invention, the inside of the aggregate must be saturated with water. This is especially due to the generation of air bubbles from within the bone phase, which is seen when using dry aggregates.
Since the adhesion of the siliceous powder to the surface of the aggregate may be hindered, it is preferable that the aggregate is always kept in a wet state. In addition, the fine aggregate used here may be river sand, crushed sand, beach sand, sea sand, etc. as long as the particles are hard.
Further, as for the coarse aggregate, crushed stone, river gravel, land gravel, sea gravel, etc. can be used.

As the cement used in the present invention, cements conventionally used in the production of concrete products, such as ordinary Portolan P cement, early strength cement, and blast furnace cement, are used.

In addition, the siliceous powder used in the present invention includes silica stone, siliceous earth, silicate clay, fly ash, metallic silicon,
Silica ash, etc., which is produced as a by-product during the manufacture of silicon alloys, is used.

If the ratio of siliceous powder to cement is less than 5 parts by weight, it will not contribute to the development of strength after autoclave curing, and if the ratio of siliceous powder to cement is greater than 40 parts by weight, addition of It is not very effective and is uneconomical, and is preferably used in an amount of 5 to 40 parts by weight per 100 parts by weight of cement.

Next, the present invention will be specifically described using Examples.

However, the method is not limited to this method.

Example 1 The results of an experiment to determine the effect of the timing of addition of silica powder on the strength of a molded body are shown.

Experimental conditions (1) Raw material cement: Ube Industries (manufactured by (1) regular grade Rutland cement aggregate Materials: Kinu river sand, coarse grain ratio 2.75, crushed stone from Kinugawa, coarse grain ratio 6.79, chemical admixture 2 Kao Mighty 150 siliceous powder manufactured by Soap Co., Ltd.: Crushed soft silica stone from Ukusu (specific surface area 2.5)
0 ocrl/y r ) (2) Centrifugal force Compaction conditions Centrifugal force 2G-10G-30G (G: Gravity speed unit operating time 3 minutes - 3 minutes - 4 minutes (3) Curing conditions Normal pressure steam curing (65℃ x 6 hours ) After that, autoclave curing (18 degrees Celsius x 5 hours) was performed.

(4) Mixing method Table 1 (5) Mixer pAN type horizontal forced mixing mixer (6) Mixing method A Conventional method mixing B Mixing according to the present invention Water content → High performance water reducing agent → (Kneaded) Adjusted water The liquid content of the mixed powder of cement and silica powder at the time of addition is 9.

(7) Results Table 2 υ Specimen dimensions/wall thickness 401m1++/outer diameter 150
0 section, length 300m + a The daily discharge rate is expressed as the weight of 70 cents discharged relative to the amount of concrete put into the centrifugal molding form.

As is clear from Table 2, when the kneading method according to the present invention was used, the compressive strength of the centrifugal compact was increased compared to the conventional method. Furthermore, the amount of slag (residue) discharged after molding was smaller than that in the conventional method, and a molded product in which the aforementioned separation layer was hardly observed was obtained.

Example 2 The results of an experiment on the influence of the timing of addition of hydraulic substance powder on the strength of a molded body are shown.

Experimental conditions +1) Raw materials cement, aggregate, and chemical admixtures were the same raw materials as in Example 1.

The centrifugal compaction conditions and curing conditions were also the same as in Example 1.

(2) Speech style combination Table 3 (3) Kneading machine pAN type horizontal forced kneading mixer.

(4) Cross-wire method A Conventional method cross-wire (5) Results Table 4 Specimen dimensions ・Wall thickness ・40 m ・Outer diameter 1501III Ring length 300 m As is clear from Table 4, the cross-wire method according to the present invention Compared to the conventional method, the compressive strength of the centrifugal compact was increased.

Thus, the present invention is extremely simple to operate and does not require any additional equipment or labor. Follow? Since the present invention can be easily implemented in the current concrete plan), the present invention can increase the effect of adding siliceous powder and reduce the amount of cement per unit in the mix in such an easily implemented configuration. They discovered that it is possible to manufacture high-quality construction piles that contribute to

Patent issue Asahi Kasei Industries, Ltd. 46

Claims (1)

[Claims] 1. When using fine aggregate and coarse aggregate, the inside of the aggregate is saturated with water beforehand and mixed with powder of a hydraulic substance such as cement or gypsum. A mixed powder consisting of siliceous powder was gradually added, mixed and stirred by dry kneading, and then the remaining blended water and chemical admixture were added and kneaded again, and this was centrifugally molded. Method 2 for producing centrifugally formed concrete products, which also includes curing with high-pressure steam at high temperatures.The mixed powder should have a ratio of siliceous powder to cement in the range of 5 to 40 parts. A method for producing a centrifugally formed concrete product according to claim 1, characterized in that: