JP2009137025A - Concrete producing method using fine closed cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a concrete producing method which is realistic and high in practicality and uses fine closed cells such as microbubbles effectively. <P>SOLUTION: After kneading water incorporated with an admixture including an AE agent and an AE water reducing agent is made to pass through a microbubble generator to produce the microbubbles of the fine closed cells, the kneading water containing the microbubbles and a residual concrete material including a coarse aggregate, a fine aggregate, and cement are kneaded to produce concrete. With regard to the produced concrete, compression strength is increased largely, concrete properties are improved, and thereby the fine closed cells such as the microbubbles can effectively be used realistically and practically in the production of the concrete. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a concrete production method for producing concrete by kneading various concrete materials such as coarse aggregate, fine aggregate, cement, kneaded water, admixture, and the like, and more particularly, producing fine bubbles in the kneaded water. The present invention relates to a method for producing concrete.

  In recent years, it is known that microbubbles having a diameter of about 50 μm or less, called microbubbles, exhibit usefulness in various technical fields such as promoting the biological activity of organisms and having a bactericidal effect against bacteria and viruses. As a result, it has been featured in many media. By the way, although the mechanism of such fine bubbles has not yet been fully elucidated and is still in the research stage, as one of methods and apparatuses using these fine bubbles, for example, the fine bubbles can be converted into cement-based materials, Several proposals have been made for mixing or generating in kneaded water.

Patent Document 1 describes a method and an apparatus in which microbubbles are mixed in place of an admixture such as an AE agent, a foaming agent, and a foaming agent in producing cement milk, mortar, or concrete. Without using an admixture such as an AE agent, a large number of fine independent bubbles are uniformly distributed in the material to improve workability and frost resistance. Further, in Patent Document 2, air is injected in the middle of a flowing water pipe, and then pressurized with a pump, and then bubbles of 50 μm or less are generated by a mixer that breaks into ultrafine bubbles to produce fine bubble water. A method for producing kneaded water for hydraulic cement is described, and according to this, the use of this kneaded water accelerates hardening of the cement, saves cement, improves fluidity, durability and operation. It is said that it can improve the performance.
JP 2007-191358 A JP 2007-261242 A

  However, in any of the above-mentioned prior inventions, no demonstration data or the like is attached, and there are not a few unclear points, so it is difficult to say that it has been sufficiently established as a practical technique, and is still in the search stage. It is believed that there is.

  In view of the above points, an object of the present invention is to provide a concrete manufacturing method that is practical and highly practical and that effectively uses fine bubbles such as microbubbles.

  The present inventors pay attention to various usefulness possessed by microbubbles such as microbubbles, as in the above-described prior invention, etc., and if the one in which fine bubbles are generated in the kneaded water is used when producing concrete. The inventors have thought that the properties of the produced concrete, such as workability and frost resistance, may be improved. Under this assumption, after actually generating fine bubbles in the kneaded water, the admixture is mixed into the kneaded water, and the remaining concrete material such as coarse aggregate, fine aggregate, cement and the like are kneaded. The concrete test was made using this concrete, and a concrete test was attempted. However, due to the characteristics of the fine bubbles, the fine bubbles generated in the kneaded water disappeared only after a few minutes. Therefore, no matter how fast the work was done, fine bubbles could not be left until kneading. For this reason, there was almost no change in the properties of the concrete produced. .

  Therefore, the present inventors repeated trial and error, and as a result of intensive research, first, after mixing a predetermined amount of admixture into the kneaded water, fine bubbles were generated in the kneaded water containing the admixture, and this If concrete is produced by kneading the kneaded water containing fine bubbles and the remaining concrete materials such as coarse aggregate, fine aggregate, cement, etc., the life of the fine bubbles will be greatly increased by the effect of the admixture. It was found that it can be used in a state in which fine bubbles remain sufficiently in the kneaded water even when kneading (a state in which white turbidity has hardly disappeared). Then, when a concrete test was attempted on a specimen made of concrete manufactured in this way, although a clear reason is not clear, normal kneading water is used due to the influence of fine bubbles in the kneading water. It is confirmed that the compressive strength is greatly enhanced compared to concrete manufactured in this way, and this is sufficiently realistic and practical as a concrete manufacturing method that effectively uses fine bubbles. I thought.

  That is, in order to solve the above-mentioned problem, in the concrete manufacturing method using the fine bubbles according to claim 1 of the present invention, the fine bubbles are removed by passing the kneaded water mixed with the admixture through the fine bubble generating means. After the production, concrete is produced by kneading the kneaded water containing fine bubbles, coarse aggregate, fine aggregate, and cement.

  Moreover, in the concrete manufacturing method using fine bubbles according to claim 2, the fine bubbles are microbubbles.

  According to the concrete manufacturing method using fine bubbles according to claims 1 and 2 of the present invention, fine bubbles such as microbubbles are generated by passing the kneaded water mixed with the admixture through the fine bubble generating means. Later, when the concrete is produced by kneading the kneaded water containing fine bubbles, coarse aggregate, fine aggregate, and cement, the compressive strength of the concrete is enhanced, and the properties of the concrete can be improved. Fine bubbles such as microbubbles can be effectively used practically and practically in the production of concrete.

  In the concrete manufacturing method using microbubbles according to the present invention, a microbubble generation means, for example, microbubble generation is performed by pumping kneaded water mixed with a predetermined amount of an admixture such as an AE agent or an AE water reducing agent. By passing the apparatus, fine bubbles such as microbubbles are generated in the kneaded water. At this time, the fine bubbles generated in the kneaded water do not disappear in a short time due to the effect of the admixture, and many fine bubbles remain for a relatively long time. Thus, the kneaded water containing a lot of fine bubbles is kneaded for a predetermined time together with the remaining concrete materials such as coarse aggregate, fine aggregate, cement and the like to produce concrete.

  And the concrete manufactured in this way expresses high compressive strength compared with the concrete manufactured using normal kneading water due to some influence of fine bubbles such as microbubbles in kneading water, and is very remarkable. It is possible to use the fine bubbles such as microbubbles extremely practically and practically for the production of concrete.

  Hereinafter, as an example of the present invention, a demonstration test (concrete test) will be described in detail.

  First, the concrete materials to be used are shown in Table 1, and the composition is shown in Table 2.

  Then, according to the blending table of Table 2, the various concrete materials shown in Table 1 are put into a forced biaxial mixer 1 having a kneading capacity of 60 liters as shown in FIG. 1, and the mixer 1 is started. Then, the mixture was kneaded for 120 seconds to produce concrete. After completion of the kneading, the concrete was discharged from the mixer, and immediately after measuring and confirming the slump and the amount of air, a specimen (100 mm diameter × 200 mm standard cylinder) was produced.

  At this time, what used tap water as it is as kneaded water (N), after generating microbubbles in tap water (microbubbles almost disappeared at the time of kneading), used as kneaded water (MB), Microbubbles were generated in tap water mixed with an admixture in advance (microbubbles remained sufficiently even at the time of kneading) and used as kneaded water (Ad-MB).

  In addition, in generating microbubbles in tap water, a microbubble generating device (manufactured by Asp Co., Ltd., model AS-K2) which is a fine bubble generating means was used. The micro-bubble generating device is mainly composed of a pump and a bubble generation unit. When air is pumped into the bubble generation unit as the pump is driven, the air is finely sheared by the inner wall of the staggered structure formed in the bubble generation unit. Eventually, the structure is such that fine bubbles such as microbubbles of 50 μm or less are generated.

And the compressive strength test (JIS A 1108) of each said test body was done to the material age 91 days. The results are shown in FIG. 2, and when the microbubbles are not present in the kneaded water (N) or almost absent (MB), the compressive strength at the age of 7 days is about 24 N / mm ^2. On the other hand, when there are many microbubbles in the kneaded water (Ad-MB), it is about 26 N / mm ² , and the effect of increasing strength by about 6% was confirmed by the presence of microbubbles. Further, in the compressive strength at the age of 28 days, (N) and (MB) are both about 31 N / mm ² , while (Ad-MB) is about 34 N / mm ² and about 9%. The compressive strength at the age of 91 days is (N) and (MB) both about 36 N / mm ² , while (Ad-MB) is 39 N / mm ^2. The strength enhancement effect of about 7% was confirmed.

  In addition, since the mass reduction rate due to drying of each specimen was also measured together with the compressive strength, the result is shown in FIG. 3, and there is almost no microbubble in the kneaded water (N) or almost absent (MB). In contrast to the same value, in the case where many microbubbles exist in the kneaded water (Ad-MB), the value was always lower than (N) and (MB).

  From the above test results, in the concrete production process, kneaded water mixed with admixtures such as AE agent and AE water reducing agent in advance is passed through a microbubble generator, for example, a microbubble generator to generate microbubbles. By doing so, it was confirmed that the fine bubbles present in the kneaded water had some influence and greatly increased the compressive strength of the concrete.

  Thus, according to the concrete production method using fine bubbles of the present invention, the kneaded water mixed with the admixture in advance is passed through the fine bubble generating means such as microbubbles, so that the interface in the admixture. The fine bubbles generated in the kneaded water by the action of the activator can remain for a relatively long time, and the kneaded water containing a large amount of the fine bubbles can be used for the remaining coarse aggregate, fine aggregate, cement, etc. It is preferable to produce concrete by kneading with concrete material, which can greatly enhance the compressive strength and bring about a significant advantage, and is suitable for the production of concrete. It can be effectively used practically.

  In this example, a microbubble generating device is employed as the fine bubble generating means, and microbubbles are generated by passing the kneaded water through the microbubble generating device. It has been reported that the generation of microbubbles called micro-nanobubbles and nanobubbles, which are considered to be much smaller in diameter than microbubbles and exhibit more remarkable utility, is becoming possible. It is also possible to employ these micro-nano bubbles and nano-bubble generation devices as generation means.

It is the top view (a) and side sectional view (b) of the mixer used for this invention. It is the graph which compared the compressive strength test result of each specimen. It is a graph which shows the mass decreasing rate by drying of each specimen.

Explanation of symbols

    1 ... Mixer

Claims (2)

  After the fine bubbles are generated by passing the kneaded water mixed with the admixture through the fine bubble generating means, the kneaded water containing the fine bubbles, the coarse aggregate, the fine aggregate, and the cement are kneaded. A method for producing concrete using fine bubbles, characterized by producing concrete.   The method for producing concrete using fine bubbles according to claim 1, wherein the fine bubbles are microbubbles.

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