JP3529052B2 - Setting retarder and method for constructing fast-setting concrete using the same - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a concrete composition using a set retarder for concrete before the addition of a quick-setting material.
The present invention relates to a concrete composition using an excellent setting retarder that can be used at a required time by using a quick-setting material together, and relates to a method for constructing a quick-setting concrete using the same .

The concrete used in the present invention is a general term for concrete and mortar.

[0003]

2. Description of the Related Art Conventionally, a set retarder has been used so that it can be used for a long period of time when concrete is used on site such as concrete spraying.

However, when a setting retarder is mixed with concrete so that the setting time of concrete is 5 to 10 hours or more, the strength after hardening is remarkably lowered as compared with the case where the setting retarder is not mixed. There was a problem that it was impossible to use the necessary concrete freely.

Further, when concrete must be used for nighttime construction, since the ready-mixed plant normally does not operate at night, it is impossible to receive the supply of concrete. There was a problem that it was necessary to build a plant from the plant, which was extremely disadvantageous economically.

In particular, this has been a problem in the field of tunnel construction where a small amount of concrete is continuously used.

In order to solve the above-mentioned problems, a method of adding condensed phosphate, citric acid, slaked lime, sodium carbonate, etc. to concrete and mixing alkali aluminate or organic acid immediately before use, or polycarboxylic acid to concrete A method of adding a salt-based admixture, maintaining fluidity for a long time, and adding a quick-setting agent at the time of use has been proposed (JP-A-2-248351, JP-A-3-153550).

However, when these organic acids are used alone, there are problems that the setting time is short, breathing occurs, the concrete becomes too soft, and the aggregate and the cement component are separated.

When the amount of the set retarder is increased so that the concrete can be used for a long time, a quick-setting material is added within a shorter time than expected, for example, within 1 to 10 hours, When sprayed, there was a problem that the sprayed concrete did not set quickly, and the sprayed concrete was washed away with water and separated from the top end.

Particularly, when the fluidity of concrete is maintained for 5 hours or more, the above problems are likely to occur.

Therefore, the conventional technique is a technique in which it is difficult to maintain the fluidity for 5 hours or more, which is the time required most at the construction site.

[0012] The construction site is usually operated in three shifts for 24 hours.

However, in the ready-mixed concrete plant, the shipment is stopped around 6 pm, and the ready-mixed concrete cannot be shipped until tomorrow morning, and there is a demand for concrete which can maintain fluidity until the time required by the construction site. It was

As a result of various studies to solve the above-mentioned problems, the inventor of the present invention can maintain fluidity by using a specific material for a time longer than required by a construction site, and when necessary. The present invention has been completed based on the knowledge that a quick setting material can be mixed and concrete can be set in a short time.

[0015]

Means for Solving the Problems That is, the present invention, including the condensation to retarder shall be the active ingredient and lime-containing substance and an organic acid
And a concrete that does not contain a quick-setting material,
5 to 15 parts by weight for 100 parts by weight of cement in concrete
Quick binding material containing calcium aluminate as a main component
A concrete composition containing and a quick-setting material.
The concrete containing no, blended該凝binding retarder, immediately prior to use of the concrete, a method of constructing the quick-setting concrete characterized by construction by mixing the quick-material.

The present invention will be described in more detail below.

The setting retarder of the present invention is a material to be added to concrete when making a quick-hardening concrete using a quick-setting material.

The slaked lime-containing substance according to the present invention means that when a large amount of organic acid or the like is used so that concrete containing no quick-setting material will not set and harden for a long time, even if the time is shorter than the planned hardening time, By using a binder together, it has the function of quickly setting and hardening.

Specific examples thereof include slaked lime and carbide slag produced as a by-product when acetylene is generated from calcium carbide. Among them, the use of the carbide slag is more preferable because the strength development after mixing with the quick-setting material is the best and the cost is economical because it is a by-product. The particle size of the slaked lime-containing substance is not particularly limited, but is preferably 100 μm or less, more preferably 60 μm or less.

As the organic acids according to the present invention, it is possible to use one or more kinds of various water-soluble carboxylic acids such as citric acid, gluconic acid, tartaric acid and malic acid or salts thereof. Among them, the use of citric acid is more preferable because the setting time is directly proportional to the amount used and the control is easy.

The amount of organic acids used is 100
The amount is preferably 1 to 400 parts by weight, more preferably 4 to 200 parts by weight, most preferably 6 to 50 parts by weight, based on parts by weight. 1
If it is less than part by weight, the retarding effect is small, and if it exceeds 400 parts by weight, it tends to be difficult to set and harden upon spraying.

The mixing conditions such as the mixing order of the slaked lime-containing substance and the organic acids are not particularly limited as long as they are uniformly mixed with the concrete before the quick-setting material is added, and division mixing is also sufficiently possible. is there. The setting retarder is preferably used in an amount of 0.5 to 12 parts by weight based on 100 parts by weight of cement in concrete. If it is less than 0.5 part by weight, the retarding effect is small, and if it exceeds 12 parts by weight, the setting and hardening tends not to occur during spraying.

Here, the cement used for concrete is not particularly limited, and various portland cements such as normal, early-strength, and ultra-early-strength, as well as these portland cements, blast furnace slag, fly ash, Alternatively, various mixed cements mixed with silica can be used.

At the time of spraying, the quick-setting material is mixed with the concrete mixed with the setting retarder.

The quick- setting material according to the present invention is used in a cement spraying method, and is mainly composed of calcium aluminate.
The concrete has excellent setting properties such as quick setting hardening of concrete, and strength development is also preferable. The amount of quick-setting material used is 5-15 per 100 parts by weight of cement.
Parts by weight. If it is less than 5 parts by weight, the setting properties will be delayed, and if it exceeds 15 parts by weight, the rebound loss during spraying tends to be large.

If necessary, it is also possible to mix concrete or a quick-setting material with a cement admixture such as a water reducing agent or an AE agent, thereby making it possible to produce shotcrete having respective properties. is there.

As the water-reducing agent, it is most preferable to use a high-performance water-reducing agent. In the present invention, even if a high-performance water-reducing agent of the naphthalenesulfonic acid formalin condensate salt type is used, a sufficiently long working time is required. You can make concrete with trash, and there is no short slump down.

Example 1 The unit amount of each material was 360 kg / m ^{3 for} cement and 1,05 for fine aggregate.
3 kg / m ^3, coarse aggregate is 708kg / m ^3, and water as 216 kg / m ^3,
A concrete with a water / cement ratio of 60% and a fine aggregate ratio of 60% was prepared, and as shown in Table 1, a setting retarder in which the compounding amount of organic acids was changed with respect to 100 parts by weight of a substance containing slaked lime was used as a cement in concrete. 7 parts by weight to 100 parts by weight was added to the concrete and mixed. The slump of the concrete immediately after kneading and the time when the slump became 10 cm were measured, and the hardening property immediately after kneading (immediately) and the hardening property when the slump became 10 cm (slump 10) were observed. The results are also shown in Table 1. The slump immediately after kneading was adjusted to 20 cm by changing the amount of water. Further, 7 parts by weight of the quick-setting material was mixed with 100 parts by weight of cement in the concrete, immediately after kneading and when the slump became 10 cm, and mixed to observe the hardening property.

<Materials used> Cement: Normal Portland cement fine aggregate manufactured by Denki Kagaku Kogyo Co., Ltd .: Coarse aggregate of river sand from Himekawa, Niigata Prefecture: River gravel from Himekawa prefecture, Niigata Prefecture A: Carbide slag Organic acids a: Citric acid, Showa Kako Co., Ltd. quick-setting material: Denki Kagaku Kogyo Co., Ltd. product name "Denkanatomic T-5" main component calcium aluminate

[0030]

[Table 1]

As is apparent from the table, in Experiment No. 1-1, 1
The time for kneading to reach 0 cm is 2 hours, and by using the setting retarder of the present invention, the curing property is not deteriorated,
It became possible to arbitrarily adjust the setting time.

Example 2 Using a mortar mixture having a water-cement ratio of 60% and a cement / fine aggregate ratio of 1/3, 7 parts by weight of a quick-setting material was added to 100 parts by weight of cement, and a substance containing slaked lime. The procedure of Example 1 was repeated, except that the setting retarder consisting of 12 parts by weight of organic acids was changed as shown in Table 2 per 100 parts by weight. The results are also shown in Table 2.

[0033]

[Table 2]

As is clear from the table, in Experiment No. 2-1 the setting and hardening time did not become long, and in Experiment Nos. 2-3 to 2-7,
The time became longer in proportion to the amount added, and even when the slump became 10 cm immediately after kneading, the quick-setting property was excellent by adding the quick-setting material.

Example 3 As shown in Table 3, except that the type of the slaked lime-containing substance and the organic acid were changed and 12 parts by weight of the set retarder was added to 100 parts by weight of cement. The procedure was as in Example 2. The results are also shown in Table 3.

<Material used> Slaked lime-containing substance B: Slaked lime from Chichibu Organic acids b: Gluconic acid, manufactured by Fujisawa Pharmaceutical

[0037]

[Table 3]

Example 4 0.5 parts by weight of a setting retarder was added to 100 parts by weight of cement, the amount of the quick-setting material was changed as shown in Table 4, and the setting agent was added immediately after kneading the mortar. The same procedure as 2 was performed. The results are also shown in Table 4.

[0039]

[Table 4]

Example 5 A spray test was conducted by spraying 1 m ³ of each of the concrete of Experiment Nos. 2-1 to 2-8 of Example 2 using a spraying machine "Aliver 280" manufactured by Fuji Bussan Co., Ltd. In the concrete using the mixture of Experiment No. 2-3 to 2-7, there is no problem in practical use, and the slump of each concrete can be sprayed without any problem until it becomes 10 cm or less. .2-4 and 2-5 had the best quick-setting properties. In Experiment No.2-1, it was difficult to use for more than 3 hours, and it was necessary to add water to the concrete on site for more than 3 hours. And when adding water to concrete, the addition of quick-setting material is 100% cement.
It is necessary to use 10 parts by weight or more with respect to parts by weight. At that time, both the short-term and long-term strengths were reduced, which was difficult in practice.

[0041] Ri by the the use of concrete composition of the present invention, there is no wood charge separation, without strength reduction, it is possible to maintain a long time the flow state for more than 5 hours. Also, even concrete with a long setting hardening time can be used as shotcrete immediately after kneading the concrete, so it is possible to knead one day's shotcrete at once, and the surplus concrete after one shot It can be used in the next spraying. Furthermore, since the ready-mixed concrete can be used under the same conditions for 20 hours or more, there is no need to make spray concrete at night. And so on.
Further, by carrying out the construction method of the present invention, it is possible to produce a quick-hardening concrete at any time immediately after mixing until the concrete loses fluidity.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI C04B 14:02 C04B 22:06 Z 22:06 24:04 24:04 22:08 Z 22:08) (56) References Kaihei 1-100045 (JP, A) JP-A-1-201056 (JP, A) JP-A-1-257156 (JP, A) JP-A-1-141862 (JP, A) JP-A-48-80120 ( JP, A)

Claims (2)

(57) [Claims] 1. A a slaked lime-containing substance and an organic acid and also contains a coagulation binding retarder you <br/> an active ingredient, it does not contain a quick-material co
Concrete and 100 parts by weight of cement in the concrete
To 5 to 15 parts by weight of calcium aluminate
Concrete composition containing a quick-setting material as the main component
Thing . 2. A concrete containing no quick-setting material is mixed with a setting retarder containing a slaked lime-containing substance and an organic acid as active ingredients, and the concrete is prepared immediately before use.
5 to 15 parts by weight per 100 parts by weight of cement in
A construction method for quick-hardening concrete, characterized in that a construction is performed by mixing a quick-setting material containing calcium aluminate as a main component .