JP2503772B2 - Fast-curing self-leveling flooring composition - Google Patents

Description

TECHNICAL FIELD The present invention relates to a quick-curing self-leveling flooring composition. More specifically, it relates to a fast-curing self-leveling flooring composition using a metallurgical slag containing calcium aluminate as a main component.

[Prior Art] Conventionally, concrete was cast, and after hardening, the surface was horizontally finished with cement mortar, but in recent years, the kneaded material with good fluidity can be simply poured into the concrete surface. Have developed self-leveling floor materials that form a good smooth surface by the natural flow of.

As self-leveling floor materials, to date, cement-based self-leveling floor materials that use hydration hardening materials such as Portland cement and gypsum-based self-leveling floor materials that use hydration hardening materials such as gypsum plaster are known. In addition, since self-leveling flooring has cracks on its surface after curing, a self-leveling flooring in which an expansive material is mixed to prevent it has been proposed (Japanese Patent Publication Nos. 58-25061 and 59-59). 45626, JP-A-60-60961).

However, these require the use of expansive materials, which are expensive industrial products, and thus the construction cost is inevitably high.

In addition, conventional self-leveling flooring takes time to cure and develop strength, and requires a curing and curing time of 1 day (24 hours or more) after placing, and if that time does not elapse, upper walking and work There is a problem that can not be carried out.

[Problems to be Solved by the Invention] In order to improve the work efficiency, which is the above-mentioned problem, the present invention provides rapid hardening without using expensive jet cement or quick setting material, and It is an object of the present invention to provide a fast-curing self-leveling floor material that is expanded at an early stage of curing without using an expensive expander for preventing dry shrinkage cracks and has a reduced dry shrinkage over a long period of time. That is, according to the present invention, by adding water and kneading, it can freely flow, fill a space without gaps by pouring, has self-leveling property that can easily form a horizontal surface, and further has a suitable flexibility. An object of the present invention is to provide a quick-hardening self-leveling flooring material that cures rapidly after use, develops high strength, maintains high strength for a long time, and does not cause shrinkage cracks due to drying. Another object of the present invention is to provide a fast-curing self-leveling flooring material that can be manufactured at a relatively low cost without requiring a particularly expensive expanding material.

(Structure of the Invention) [Means for Solving Problems] The inventors of the present invention have conducted earnest research to solve these problems, and as a result, Japanese Patent Application No. 61-103125 and Japanese Patent Application No. 62-11
In No. 0601, it was found that the problem can be easily solved by improving the [quick-setting cement] proposed by the present inventors. Therefore, the gist of the present invention is that, first, 100 parts by weight of metallurgical slag is added to type II anhydrous gypsum
The crushed mixture obtained by mixing and crushing 40 to 50 parts by weight was used as a fast-curing material, and used as Portland cement or mixed cement.
20 to 50 parts by weight of this fast-curing material, 0 parts by weight, coarse powder I
A rapid-curing, self-leveling composition for flooring, characterized in that 5 to 15 parts by weight of type I anhydrous gypsum, and an appropriate amount of a setting regulator, a fine aggregate, a thickener, and a water reducing agent are mixed and added. .
Further, the metallurgical slag contains at least 50% by weight or more of a calcium aluminate compound, and the calcium aluminate compound can be mainly 12CaO · 7Al ₂ O ₃ .

Further, to explain, the fast-setting cements described in [Japanese Patent Application No. 61-103125] and [Japanese Patent Application No. 62-110601] are roughly
Mixture composed of metallurgical slag; 10 to 70 parts by weight, type II anhydrous gypsum; 4 to 40 parts by weight, and setting retarder; 0.5 to 5 parts by weight, based on 100 parts by weight of Portland cement or mixed cement It is a crushed fast-setting cement.

On the other hand, according to the present invention, in order to develop early strength in the composition for flooring with quick-curing self-leveling property, a large amount of by-product metallurgical slag produced in the steelmaking process and type II anhydrous produced from the hydrofluoric acid manufacturing process are produced. By mixing gypsum and adding it to ordinary Portland cement, blast furnace cement or other mixed cement as a quick-hardening material, quick-hardening can be exhibited. However, this hardened material exhibits dry shrinkage similar to ordinary cement. In order to reduce this, by further adding 5 to 15% by weight of type II anhydrous gypsum in the agglomerated form, it expands by about 10 to 30 × 10 ^{-4 at the} initial stage of curing and reduces the drying shrinkage after that. , Which gives early strengthening and expandability. At that time, as the coarse powder type II anhydrous gypsum, hydrofluoric acid type II anhydrous gypsum, which is a by-product gypsum, is good, and
It has been found that the amount added is in the range of 5 to 15 parts by weight, and when these are out of the range, the above-mentioned length change characteristics cannot be maintained.

Therefore, according to the present invention, first, the metallurgical slag and the type II anhydrous gypsum are mixed into a fast-curing material, and the fast-curing material 20 to 5 is added to 100 parts by weight of Portland cement or mixed cement.
0 parts by weight, 5 to 15 parts by weight of coarse powder type II anhydrous gypsum, and an appropriate amount of a set retarder, a fine aggregate, a thickener, and a water reducing agent are mixed and added to the quick-setting self-leveling floor of the present invention. The composition for wood is obtained.

For 100 parts by weight of metallurgical slag, 40 to 50 parts by weight of type II anhydrous gypsum is optimal. Below 40 parts by weight, strength development is low, and above 50 parts by weight, the hardened body continues to expand for a long time. I will end up. Also, Portland cement or mixed cement
20 to 50 parts by weight of the fast-curing material is suitable for 100 parts by weight. This is because the strength development is low when the rapid hardening material is 20 parts by weight or less and the remarkable strength development cannot be expected when it is 50 parts by weight or more. The amount of coarse powder type II anhydrous gypsum added is preferably 5 to 15 parts by weight. This is added for the purpose of reducing the dry shrinkage of the obtained cured product, and its addition is indispensable. If the addition amount is 3 parts by weight or less, the initial expansion phenomenon cannot be expected at all, This is because if the addition amount is 20 parts by weight or more, the expansion will be excessive, and cracks may occur in the obtained cured body.

The setting mixture, the thickener, the water reducing agent and the fine aggregate are kneaded and kneaded with the obtained hydraulic mixture to obtain a self-leveling flooring material.

The setting regulator used in the present invention includes citric acid,
Among tartaric acid, gluconic acid and salts of these organic acids, it is preferred to use one kind or a combination of two or more kinds and to mix it with an alkali carbonate such as sodium carbonate. The mixing ratio is preferably in the range of 0.5 to 7 parts by weight of alkali carbonate with respect to 1 part by weight of the organic acid agent. Addition of only organic acid as a coagulation modifier slows the reaction significantly and delays curing, but addition of alkali carbonate causes rapid curing after continuing fluidity for a certain period of time. Therefore, it is suitable for exhibiting the characteristics of the self-leveling flooring material of the present invention. As the alkali carbonate, either sodium carbonate or potassium carbonate can be used, but it is preferable to use sodium carbonate in terms of cost.

The fine aggregate used in the present invention includes calcium carbonate powder, sand,
One or more types can be selected and used from fly ash, silica sand, etc. The mixing amount is determined according to the required strength and is not limited.

Further, as a breathing inhibitor, a thickener (that is, a water retention agent) is used. For example, it is selected from commercially available carboxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl methyl cellulose, etc.
0.1 to 0.5 parts by weight is preferred.

The water reducing agent is selected from sulfonated modified resins of melamine formaldehyde condensate, condensates of naphthalene sulfonic acid and modified lignin, and the like. The addition amount is preferably 0.5 to 1.0% by weight based on the total amount of the fast-curing material.

Further, if necessary, an antifoaming agent is used, and its addition amount is preferably 0.1 to 0.5% by weight based on the total amount of the fast-curing material.

[Operation] As described above, by adding and mixing the rapid-hardening material obtained by mixing and pulverizing the metallurgical slag containing calcium aluminate and type II anhydrous gypsum to Portland cement or mixed cement, at the initial stage of hydration, Hydration of calcium hydroxide, calcium aluminate and gypsum in the cement produces ettringite in the form of fine needles,
By exhibiting quick-setting property, initial strength is expressed. Furthermore, the long-term strength of the obtained hardened body is increased by the calcium silicate-based hydrate in Portland cement or mixed cement. However, the dry shrinkage of the obtained cured product was initially 1 to 2 × due to the formation of ettringite.
Although expansion of about 10 ^-4 is recognized, the amount of shrinkage becomes similar to Portland cement as the material ages. Here, the feature of the present invention is the secondary addition of coarse powder type II anhydrous gypsum. As described above, the rapid-hardening material obtained by mixing and crushing metallurgical slag and type II anhydrous gypsum and the hardened body of Portland cement or mixed cement have a small expansion amount at the initial age, It has been found that the secondary addition of coarse powder type II anhydrous gypsum produces a phenomenon similar to that when a commercially available expander is used. That is, it is possible to prevent dry shrinkage cracks by expanding the cured product at the very early age.

Although it was not possible to clarify this phenomenon, in general,
The type II anhydrous gypsum produced as a by-product in the hydrofluoric acid manufacturing process has large particles,
Moreover, in many cases, they are agglomerated. Under such circumstances, the reaction with highly reactive calcium aluminate and calcium hydroxide in the liquid phase locally increases the concentration of sulfate ions and causes the formation of ettringite crystals. It is assumed that the shape is different and that it expands.

The optimum amount of this secondary addition of coarse powder type II anhydrous gypsum is the total amount
5 to 15 parts by weight based on 100 parts by weight, and the initial age is 10
It can be expanded up to about 30 × 10 ^-4 , then it hardly expands in water, and the amount of contraction can be suppressed to almost zero during curing in the atmosphere. Therefore, when the addition amount of the secondary type II anhydrous gypsum was 3 parts by weight or less, the expansion amount was small, and when it was 20 parts by weight or more, the expansion was excessive and cracks were generated in the obtained cured body.

In the above range of addition amount, type II anhydrous gypsum is formed in ettringite crystals at a very early age, and unhydrated type II anhydrous gypsum does not exist. As a result, excessive swelling of the hardened body does not occur during the transition to CaSO ₄ · 2H ₂ O.

As the floor material for quick-curing self-leveling property of the present invention,
Rapid hardening is Ca elution from hydraulic materials (cement etc.)
It uses the quick-setting property due to the reaction of (OH) ₂ , type II anhydrous gypsum, and 12CaO · 7Al ₂ O _{3. From} that point, if cement is added to some extent, the effect on the rapid hardening property is expected. it can.

The amount of setting regulator added is 0.5 to 5 relative to the hydraulic material.
%, And it is essential to add a coagulation modifier to the self-leveling flooring material of the present invention. In the case of no addition, it hardens immediately after water injection, and it becomes impossible to satisfy the self-leveling characteristics. It will be impossible.

The degree of primary crushing of the metallurgical slag must be such that it has at least a specific surface area of 3000 cm ² / g. Furthermore, type II anhydrous gypsum is added and mixed to make a rapid hardening material. By homogeneously mixing this with Portland cement or mixed cement, rapid hardening is enhanced, and short-term strength up to 1 day after hardening is increased. According to the invention, further coarse powder type II anhydrous gypsum must be added, and the type of type II anhydrous gypsum is not specified. This type II anhydrous gypsum is to reduce shrinkage during setting.
That is, by adding and mixing the type II anhydrous gypsum, the self-leveling flooring material of the present invention is expanded to some extent in the initial stage of curing and the subsequent contraction is reduced.

The content rate of calcium aluminate contained in the metallurgical slag is usually 40% by weight or more, but higher calcium aluminate is preferable, and 50% by weight or more is preferable.

Next, a method for producing the fast-curing self-leveling flooring composition of the present invention will be described with reference to specific examples.
It is not limited to the following examples.

[Example] 43 parts by weight of hydrofluoric acid type II anhydrous gypsum was mixed with 100 parts by weight of a metallurgical slag, and the mixture was pulverized to a specific surface area (Blaine value) of 4000 g / cm ² to obtain fast-hardening materials. To 100 parts by weight of ordinary Portland cement, 43 parts by weight of this fast-curing material and secondary addition type II anhydrous gypsum produced by secondary addition of coarse hydrofluoric acid were added.
3.0 to 20 parts by weight were added. To 100 parts by weight of the above-mentioned ordinary Portland cement and fast-curing material, 1 part by weight of a setting regulator (a mixture of oxycarboxylic acid and sodium carbonate = 1: 3 (parts by weight)), a thickener (Sunrose, 0.15 parts by weight of Sanyo Kokusaku Pulp Co., Ltd. and 1.0 part by weight of a water reducing agent (Melment, Showa Denko KK) were added, and fine aggregates of each composition shown in Table 1 were thoroughly mixed with a shaker type mixer. Each sample was prepared by kneading and kneading.

For comparison, as a comparative example, sample numbers * 1 to * 3 in which hydrofluoric acid type II anhydrous gypsum was not secondarily added and mixed,
The test was carried out on the ones crushed at the same time. Various physical properties of the above sample numbers 1 to 6 and comparative samples * 1 to * 3 were measured. Table 2 shows the results. This reference sample * 1 corresponds to the composition of Experiment No. 1, and the reference sample * 1
2 corresponds to the composition of Experiment No. 2 and the reference sample * 3 corresponds to the composition of Experiment No. 5,
This is a comparison between the case where the coarse powder type II anhydrous gypsum is secondarily added and the case where it is not added.

In the sample of Experiment No. 1, the length change in the air was large,
It is clear that it is not suitable as a fast-curing self-leveling flooring composition. Similarly, the sample of Experiment No. 6 has a large expansion coefficient and is not suitable for a quick-curing self-leveling flooring composition. Further, comparing with the comparative samples * 1 to * 3 in which type II anhydrous gypsum was added and mixed at one time and the experiment numbers 1, 2, and 5 in which the secondary addition and mixing according to the present invention were performed, for the quick-hardening self-leveling flooring material according to the present invention It can be seen that the composition has a significantly improved rate of change in length in air.

The flow value was measured using a JIS-R-5201 cement physical test flow cone without dropping 15 times.

The setting time is based on the method specified in JIS R5201 Cement Physical Testing Method, and the starting time and the ending time are shown in the table.

Regarding the compressive strength, the above kneaded product was molded into 4 × 4 × 16 cm, taken out after each time shown in the table, and the compressive strength was measured according to JIS R5201.

The rate of change in length is based on the base length after demolding one day after molding, and the change in length due to expansion when held in water and drying shrinkage when held in a temperature-controlled room at 20 ° C and 60%. It was measured.

It is shown that, compared with the conventional self-leveling flooring material, the quick-curing self-leveling flooring composition of the present invention can provide a cured product in which cracking due to drying shrinkage is prevented.

[Effect of the invention] The composition for a floor material with a self-leveling quick-curing property of the present invention is
About 4 hours after construction by adding a quick-hardening material consisting of special metallurgical slag and type II anhydrous gypsum to ordinary cement, etc.
We provide a quick-hardening, self-leveling flooring material that exhibits a compressive strength of 20 kgf / cm ² or more, and does not hinder the work on the construction surface. That is, the secondary addition of coarse type II anhydrous gypsum causes the initial expansion, reduces the drying shrinkage after that, and prevents the occurrence of cracks,
Technical effects such as being able to provide an inexpensive quick-hardening floor material for self-leveling were obtained.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical indication C04B 111: 62 C04B 111: 62 (72) Inventor Takeshi Kono 2270 Yokose, Yokose-cho, Chichibu-gun, Saitama Prefecture Mitsubishi Mining Cement Co., Ltd. Central Research Laboratory (72) Inventor Akira Hosako 2270 Yokose, Yokose-cho, Chichibu-gun, Saitama Prefecture Mitsubishi Mining Cement Co., Ltd. Central Research Laboratory (56) Reference JP-A-63-277542 (JP, A) JP-A-62-260749 (JP, A) JP-A-62-171955 (JP, A) JP-A-58-69754 (JP, A) JP-A-56-84358 (JP, A)

Claims (2)

(57) [Claims] 1. A pulverized mixture obtained by mixing and pulverizing 40 to 50 parts by weight of type II anhydrous gypsum with 100 parts by weight of a metallurgical slag as a fast-curing material, based on 100 parts by weight of Portland cement or mixed cement. 20 to 50 parts by weight of this fast-curing material,
5 to 15 parts by weight of coarse powder type II anhydrous gypsum, and an appropriate amount of a setting regulator, a fine aggregate, a thickener, and a water reducing agent are mixed and added, and a composition for a quick-curing self-leveling flooring material. . 2. The metallurgical slag contains at least 50% by weight or more of a calcium aluminate compound, and the calcium aluminate compound is mainly 12CaO.7Al ₂ O _3. A composition for a flooring material, which has a self-leveling property and is fast-curing.