JP2002293594A - Accelerator for fast hardening cement and rapid hardening cement composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fast hardening cement composition which can adjust a pot life, and fast harden after pre-hardening time, and to provide an accelerator for the fast hardening cement. SOLUTION: The accelerator for fast hardening cement is composed of a sintered compact containing solid solution of a crystalline 11CaO.7Al2 O2 .CaF2 , the lattice constant of which is 1.1971-1.1990 nm, preferably 1.1971-1.1981 nm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a quick-setting agent for quick-hardening cement and a quick-hardening cement composition which exhibit rapid hardening properties when added to cement.

[0002]

2. Description of the Related Art In a concrete spraying method in which a cement mixture such as mortar or concrete is sprayed onto a wall surface with compressed air for construction, etc., a minimum required working time (handling time (hereinafter, referred to as HT) when preparing concrete or the like is required. It is necessary to cure concrete or the like immediately while spraying the wall.

[0003] Conventionally, as such concrete for rapid hardening, one containing calcium aluminate as a rapid hardening component is known. However, since the calcium aluminate cures simultaneously with water injection,
The working time cannot be sufficiently ensured, and the mixing becomes insufficient, making it difficult to obtain good concrete. It has been proposed to add a setting retarder in order to obtain a working time. However, adding a setting retarder to calcium aluminate often causes a problem that not only the setting but also the development of strength is delayed.

[0004] In order to meet such a demand, it has been reported to use a cement containing crystalline calcium aluminate (Japanese Patent Laid-Open No. 4-209938). By using crystalline calcium aluminates, the working time can be easily secured, and the curing time after spraying is reduced.

[0005] However, when crystalline calcium aluminates are used, rapid hardening tends to be too high, so that the aggregate or the like rebounds without spraying on the wall surface at the time of spraying, resulting in a loss of material. Loss may increase.

[0006]

SUMMARY OF THE INVENTION The main object of the present invention is to:
It is to provide a quick-hardening cement composition and a quick-setting agent for the quick-hardening cement, which can secure a predetermined pot life and quickly cure after the pot life elapses. Is to provide a quick-hardening cement composition and a quick-hardening agent for quick-hardening cement, which can express the most effectively.

[0007]

Means for Solving the Problems The present inventor has conducted intensive studies to achieve the above object, and as a result, has found that crystalline 11C
together found to have a hydraulic sintered body excellent including _{aO · 7Al 2 O 3 · CaF} 2 solid solution, further, the results of extensive further study the nature of the sintered body obtained in this manner, the lattice The inventors have found that the properties of these sintered bodies differ greatly due to slight differences in the constants, and have completed the present invention.

That is, the solution of the present invention is that the lattice constant is
1.1971 to 1.1990 nm, preferably 1.19
Crystalline 11CaO · 7 with 71 to 1.1981 nm
Al _TwoO_Three・ CaF_TwoA sintered body containing a solid solution is compounded
Quick-setting cement for quick-setting cement
You.

Conventionally, a crystalline 11CaO.7Al ₂ O ₃ .CaF ₂ solid solution has been used without any particular limitation on the lattice constant. In the present invention, however, the lattice constant is 1.19.
71-1.1990 nm, preferably 1.1971-
By using a sintered body limited to the range of 1.981 nm, a sufficient pot life can be ensured, and then an excellent quick-setting cement for rapidly hardening cement can be quickly cured. Therefore, by blending the quick-setting cement for quick-setting cement with other cement or aggregate, it can be used as an excellent quick-setting cement mixture.

[0010] Further, the solid solution is added to the sintered body by 40%.
In the quick-setting cement for rapid-hardening cement which is contained in a proportion of not less than 45% by weight.
In a quick-setting cement for rapid-hardening cement.

Further, the solution of the present invention is that the lattice constant
1.1971 to 1.1990 nm, preferably 1.19
Crystalline 11CaO · 7 with 71 to 1.1981 nm
Al _TwoO_Three・ CaF_TwoA sintered body containing a solid solution is compounded
A rapid-hardening cement composition comprising:

[0012] The compounding amount of the sintered body is 2.5 to 12
It is in a rapidly hardening cement composition in weight percent.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The rapidly hardening cement composition according to the present invention has a lattice constant of 1.1971 to 1.1990 nm, preferably 1.1971 to 1.1981 nm, more preferably 1.1978 to 1.981 nm. Crystalline 11
It was blended sintered body containing _{CaO · 7Al 2 O 3 · CaF} 2 solid solution is made by. Such a sintered body can be obtained by sintering a calcium aluminate sintering raw material comprising a calcareous raw material, an alumina raw material and a calcium fluoride raw material. Hereinafter, an example of a method for manufacturing the sintered body will be described.

First, a calcareous raw material, an alumina raw material and a calcium fluoride raw material are combined with 11CaO · 7
The Al ₂ O ₃ .CaF ₂ solid solution is mixed so as to have a composition ratio. For example, limestone can be used as the calcareous material, bauxite can be used as the alumina material, and fluorite can be used as the calcium fluoride material.

Calcium aluminate thus formulated
Fe as an additive _TwoO_ThreeAnd TiO_TwoDistribute
Combine. Fe_TwoO_ThreeIs 0.1 to 9 in all raw material components.
% By weight._TwoThe amount of
It is preferable that the content is about 0.5 to 9% by weight based on all raw material components.
No. When these additives are blended, when the raw material is fired,
A low-temperature melt phase is formed in 11CaO.7Al_TwoO_Three・ C
aF_TwoAt a temperature below the melting temperature of
Crystalline 11CaO.7Al depending on the sintering method_TwoO_Three
・ CaF_TwoCan be obtained.

For the firing, for example, a method employing a method of sintering using a melt represented by a rotary kiln as a medium, or an electric furnace can be used. Firing temperature, it is necessary that the temperature below the melting temperature of the _{11CaO · 7Al 2 O 3 · CaF} 2 solid solution. Specific firing temperature depends on the type of calcium aluminate to be formed,
Although it depends on the firing method, etc., in the present invention, approximately 1225
By firing at a temperature in the range of １４1415 ° C., preferably 1225 to 1320 ° C., and more preferably 1260 to 1320 ° C., a sintered body having the above-described lattice constant can be obtained. In addition, the firing time may be usually about 1 to 2 hours in an electric furnace.

After sintering, a sintered body containing a crystalline 11CaO.Al ₂ O ₃ .CaF ₂ solid solution having a predetermined lattice constant is obtained, and then quenched with air or water to obtain the desired sintering. The conjugate can be obtained as a clinker.

The sintered body contains the above crystalline 1
As components other than _{1CaO · 7Al 2 O 3 · CaF} 2 solid solution, depending on the impurities and firing conditions contained in the raw material, 12
CaO.7Al ₂ O ₃ , 3CaO.Al ₂ O ₃ and CaO.
Various calcium aluminates such as Al ₂ O ₃ and amorphous components may be contained.

The sintered body may be pulverized to an appropriate particle size according to the purpose. Although the particle size is not particularly limited, it is usually in the range of 2000 to 8 in terms of Blaine specific surface area.
It may be about 000 cm ² / g.

The quick-setting cement for hardening cement of the present invention (hereinafter, also referred to as essence) is used to make the sintered body 45-45.
90% by weight, and as another hydraulic material, 10 to 40% by weight of an alkali aluminate such as sodium aluminate or an alkali carbonate such as sodium carbonate. Trace components such as sodium sulfate, hemihydrate gypsum and slaked lime are added in a range of 10% by weight or less.

However, crystalline 11CaO.7A
A sintered body containing l ₂ O ₃ .CaF ₂ solid solution has a different setting rate due to a difference in the lattice constant of the solid solution, and it is only necessary to mix a sintered body containing a solid solution having an arbitrary lattice constant. It is not always possible to adjust the setting time optimally.

Therefore, the lattice constant is 1.1971 nm or more.
In order to use a solid solution having a diameter of 1.1990 nm to exhibit the optimum properties as a quick-setting binder, the following formulation is preferable.

First, the lattice constant of the solid solution is 1.1978 n
When it is in the range of from m to 1.1981 nm, the solid solution itself is very excellent in rapid hardening property. Also, it is possible to prepare an excellent essence in which coagulation starts 1 to 5 minutes after water injection and ends after 10 to 15 minutes from water injection.

The solid solution has a lattice constant of 1.197.
When the thickness is from 1 nm to 1.1972 nm, although the solid solution itself is excellent in rapid hardness, it is not preferable as an essence to mix too much alkali aluminate or alkali carbonate. Therefore, specifically, it is preferable that the alkali aluminate be 20% by weight or less and the alkali carbonate be 10% by weight or less.

On the other hand, the solid solution has a lattice constant of 1.198.
When the thickness is 2 nm to 1.1990 nm, the solid solution itself has a slightly inferior hardening property as compared with a solid solution having a lattice constant of 1.9778 nm to 1.1981 nm. Therefore, it is preferable to add a relatively large amount of an alkali aluminate or an alkali carbonate as an essence. Specifically, the compounding amount of the solid solution is 45 to 50% by weight.
It is preferable that alkali aluminate is added in an amount of 30% by weight or more, more preferably 40% by weight or more, and further an alkali carbonate is added in an amount of 10 to 20% by weight.

The essence thus formulated is:
A quick-setting cement composition can be prepared by mixing with another base cement, and a cement mixture for spraying, that is, mortar or concrete can be prepared by adding water, aggregate, and the like. When adding the quick-setting agent for the quick-hardening cement of the essence to the base cement, it is preferable to mix the quick-setting agent at a ratio of 2.5 to 12% by weight based on the base cement. Various Portland cements and various mixed cements can be used as the base cement.

[0027] Further, as the rapid-hardening cement composition, regardless of whether or not the quick-setting cement quick-setting agent is used, the amount of the sintered body is the same as the amount added by the essence,
That is, it is preferable that the content is 1.3 to 9% by weight based on the base cement.

The rapid-hardening cement composition thus prepared can be used by the same procedure of spraying concrete or the like as in the past.

The quick-setting cement for quick-setting cement and the quick-setting cement composition according to the present invention can be used not only for the concrete spraying method but also for repair work, lining work, etc.
It can be used for other hardening applications such as backfilling.

[0030]

EXAMPLES (Preparation of the sintered body) limestone, bauxite, fluorspar, with TiO ₂ and Fe ₂ O ₃ as further additives, mixing these raw materials so as to be blended composition shown in Table 1 .

[0031]

[Table 1]

After sintering these raw materials in an electric furnace at the sintering temperatures shown in Table 4 for about 1 hour, they were immediately taken out of the furnace and rapidly cooled.
It was pulverized to 300 ± 100 cm ² / g to obtain a sintered body. Further, the amount of unreacted CaO in the sintered body was 0.5% or less, and it was confirmed that the clinker formation reaction had sufficiently proceeded. Further, by separating the calcium aluminate phase in the sintered body and measuring the amount of fluorine, 11CaO
Formation of calcium aluminates containing 7Al ₂ O ₃ .CaF ₂ solid solution was confirmed.

Further, the lattice constant of the calcium aluminate phase was measured under the following conditions. (Measurement method of lattice constant) The lattice constant was determined by using RAD by Rigaku Denki Co.
The measurement was performed by powder X-ray diffraction using an -rC system. Table 4 shows the measurement results of the lattice constant.

[0034]

[0035]

[Table 2]

(II) Calculation of lattice constant The diffraction angle is read by the half-width half-point method, and the correction of the diffraction angle is performed by calculating a correction value from the diffraction line of the obtained internal standard sample, and by the least square method. went.

(Preparation of mortar) Using the above sintered body, a quick setting agent for a rapidly hardening cement (hereinafter referred to as an essence) having the composition shown in Table 3 was prepared. A mortar strength test method (JISR 5) was conducted using ordinary Portland cement manufactured by Sumitomo Osaka Cement Co., Ltd. and quartz sand from Seto City, Aichi Prefecture.
201) The mortar was kneaded in accordance with 201), allowed to stand for 30 minutes, and then the above-mentioned essence was added and kneaded for 30 seconds to prepare the hardened cement (mortar) of Examples and Comparative Examples. Table 4 shows the mortar composition. The water / cement ratio was 0.5, the cement / sand ratio was 1/3, and the essence was added at a ratio of 7 parts by weight to 100 parts by weight of the cement.

[0038]

[Table 3]

[0039]

[Table 4]

(Test Method) For these mortars,
Concrete condensation test method (JIS R 6204)
Starting and ending times were measured by a proctor penetration resistance test according to the above, and the rapid hardening was evaluated. The test temperature was 5 ° C. The mortar thus prepared was subjected to a compressive strength test. The compressive strength test was conducted according to a mortar strength test method (JIS R5201), and the compressive strength was measured at a material age of 12 hours, a material age of 1 day, and a material age of 28 days. The test temperature was 5 ° C. Table 5 shows the results.

[0041]

[Table 5]

As shown in Table 5, according to the embodiment of the rapid-hardening cement according to the present invention, the initial set time was 3 hours.
It can be seen that the end is reached within a short time of 6 to 13 minutes. On the other hand, in Comparative Example 1, it takes 30 minutes to finish, and in Comparative Example 2, it takes 15 minutes. In Comparative Example 3, the starting time was 1
It is less than a minute, and a sufficient pot life cannot be secured. In addition, the compressive strengths of Examples 1 to 4 are equal to or higher than those of the conventional rapid-hardening cement, but the comparative examples do not satisfy the compressive strength of 12 hours or 1 day. You can see that it is.

(Tests as Shotcrete) Essences having different lattice constants were prepared by the same procedure as described above, and evaluation was made as shotcrete using the parameters of the lattice constant and the amount of essence added and added as parameters. The concrete test method is based on the Japan Society of Civil Engineers standard “Quick setting agent quality standard for shotcrete (draft)” (JSCE-D 1
02-1986). That is, the setting time (2
8. 0 N / mm ² Within 15 minutes 28 N / mm ² Compressive strength (20 ° C., 80% Rh) 12 hours 1.00 N / mm ² or more 24 hours 9. 00 N / mm ² or more 28 days NC × 75% or more was used as an evaluation standard.

The evaluation methods were as follows: those satisfying both the setting time and compressive strength were evaluated as ◎; those satisfying the compressive strength and having a slightly slower setting time were evaluated as ○; those satisfying only the setting time as Δ; Those that do not satisfy any of them are represented by x. The results are shown in Table 6 below.

[0045]

[Table 6]

According to Table 6, the lattice constant is 1.1971 to
It can be seen that, within the range of 1.1990 nm, the essence satisfies the standard as a quick setting agent for shotcrete by changing the amount of the sintered body and the amount of essence added. In particular, the lattice constant is 1.1971-
1. Within the range of 981 nm, the ratio of the sintered body is 9
It can be used up to about 0%, in other words, without using sodium carbonate at all, and with the minimum amount of sodium aluminate, the essence can be used as a quick setting agent for shotcrete. It turns out that it can be used.

[0047]

As described above, by using the rapid-hardening cement composition or the quick-setting agent for quick-hardening cement according to the present invention as a predetermined compound, it is possible to obtain a stable and hard-to-set concrete for quick-hardening applications. In addition, excellent rapid hardening can be effectively exhibited. Therefore, it is possible to easily prepare the hardened cement composition at a work site or the like.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Tatsuo Isobata 7-55 Minamienkajima Taisho-ku, Osaka City Sumitomo Osaka Cement Co., Ltd. F-term in Cement Concrete Research Laboratories 4G012 MB08 PA04 PB05 PB09 PC04

Claims (8)

[Claims] 1. A lattice constant of 1.197 to 1.1990.
of crystalline is _{nm 11CaO · 7Al 2 O 3 ·} CaF 2
A quick-setting agent for rapidly hardening cement, comprising a sintered body containing a solid solution. 2. The lattice constant is 1.1971 to 1.1981.
of crystalline is _{nm 11CaO · 7Al 2 O 3 ·} CaF 2
A quick-setting agent for rapidly hardening cement, comprising a sintered body containing a solid solution. 3. The 11CaO.7Al ₂ O ₃ .CaF _2.
3. The quick-setting cement for rapidly setting cement according to claim 1, wherein a solid solution is contained in the sintered body at a ratio of 40% by weight or more. 4. The quick-setting cement for rapidly setting cement according to claim 1, wherein said sintered body is blended at a ratio of 45 to 90% by weight. 5. A lattice constant of 1.197 to 1.1990.
of crystalline is _{nm 11CaO · 7Al 2 O 3 ·} CaF 2
A rapidly hardening cement composition comprising a sintered body containing a solid solution. 6. The lattice constant is 1.1971 to 1.1981.
of crystalline is _{nm 11CaO · 7Al 2 O 3 ·} CaF 2
A rapidly hardening cement composition comprising a sintered body containing a solid solution. 7. The rapidly hardening cement composition according to claim 5, wherein the sintered body is added in an amount of 1.3 to 9% by weight based on the base cement. 8. A rapid-hardening cement composition comprising the quick-setting cement according to claim 4 and 2.5 to 12% by weight of the base cement.