JP2013147392A - High belite-based clinker composition excellent in initial strength development, method for producing the same, and high belite-based cement composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high belite-based clinker composition capable of increasing initial strength of high belite-based clinker and a high belite-based cement composition using the clinker without changing the amount of a mineral composition of high belite-based cement clinker containing 50-70 mass% CS, and enhancing long-term strength by heightening hydration activity of CS; and to provide a method for producing the same, and a high belite-based cement composition.SOLUTION: In a high belite-based clinker composition. which is a high belite-based clinker composition containing 50-70 mass% CS, the M1 phase in CS is ≥12 mass%, and the mass ratio (M1/C3S) of the M1 phase to the CS is ≥45 mass%. Further, when producing the high belite-based clinker composition as much as 1t, chaff ashes are blended as much as 25-250 kg and calcined.

Description

  The present invention relates to a high belite clinker composition excellent in initial strength development, a manufacturing method thereof, and a high belite cement composition, particularly used in civil engineering and construction fields, and excellent in initial strength development. The present invention relates to a high belite clinker composition, a method for producing the same, and a high belite cement composition, the strength of which increases as desired from the beginning to the long term.

Various low heat-generating cements such as high belite-based cement and high belite-based mixed cement have been developed from the viewpoint of suppressing heat of hydration in mass concrete such as dams. Has been pointed out.
In order to improve this point, Japanese Patent Application Laid-Open No. 7-215742 (Patent Document 1) and Japanese Patent Application Laid-Open No. 8-175854 (Patent Document 2) describe a belite-based cement composition excellent in initial strength development. As a production method, there has been proposed a method in which belite-based clinker, alite-based clinker and gypsum are blended in an arbitrary ratio and mixed and pulverized.

  Japanese Patent Laid-Open No. 6-287046 (Patent Document 3) discloses a method of blending high belite type cement with calcium carbonate, blast furnace slag powder, etc. to obtain a mixed cement. No. 4 (Patent Document 4) exemplifies a low heat cement with an initial strength expressed by a cement composition composed of a high belite cement and a blast furnace slag fine powder and a setting retarder.

  Furthermore, Japanese Patent Laying-Open No. 2005-67905 (Patent Document 5) proposes a manufacturing method in which a cement clinker containing alite and a substance containing silicon dioxide as a main component are contact-reacted in a temperature range of 1100 ° C. or higher. Cement clinker composition containing belite produced by decomposition of alite in clinker by such a production method, and belite produced by reaction of calcium oxide and silicon dioxide containing product produced by decomposition of alite Is disclosed.

However, for example, the method disclosed in Japanese Patent Laid-Open No. 6-287046 (Patent Document 3) has a high blending ratio of blast furnace slag contained in low heat cement prepared from high belite clinker, and thus prepared cement. There is a problem in the initial strength development property, and the strength development tends to vary due to the quality of the mixed material.
Further, in the method of mixing and grinding belite clinker, alite clinker and gypsum as exemplified in JP-A-8-175854 (Patent Document 2), belite clinker and alite clinker are used. Since it is necessary to manufacture each clinker, a lot of energy is required, and the resulting cement is affected by variations in the mineral composition of each clinker. Therefore, careful preparation is required.

  The method of contact reaction of alite clinker and silicon dioxide at 1100 ° C., exemplified in JP-A-2005-67905 (Patent Document 5), after the alite clinker is produced, is further processed at a high temperature, etc. Manufacturing requires a lot of energy.

Any of the above conventional methods are intended to satisfy the specified initial strength development performance by combining clinker and raw materials with different performance, and improve the initial strength development by improving the quality of the clinker itself. It's not something
In addition, although conventional heat-resistant cements are excellent in reducing the heat of hydration, the initial strength is greatly reduced, and the type of mixed materials such as clinker increases, so the quality of these mixed materials is affected. There is a problem that it is easy to receive.

Japanese Patent Laid-Open No. 7-215742 JP-A-8-175854 Japanese Patent Laid-Open No. 6-287046 JP-A-9-227182 JP 2005-67905 A

Usually, low heat Portland cement decreases C ₃ S and C ₃ A to suppress the hydration heat value and increases C ₂ S, so that the initial strength is lowered.
Accordingly, an object of the present invention is to provide a high belite clinker and a high belite cement composition using the clinker without changing the mineral composition amount of the high belite cement clinker containing 50 to 70% by mass of C ₂ S. A high belite clinker composition, a method for producing the same, and a high belite cement composition that can increase the initial strength of the product and increase the hydration activity of C ₂ S to enhance long-term strength. It is to be.

In order to solve the above-described problems, the present invention improves the initial strength development by increasing the content ratio of the M1 phase in C ₃ S constituting the high belite cement clinker, and the C ₂ S α 'It has been found and achieved that the phase can be increased to increase the hydration reactivity and increase the long-term strength of the cement.

That is, the high belite clinker composition of the present invention is a high belite clinker composition containing 50 to 70% by mass of C ₂ S, and the M1 phase in C ₃ S is 12% by mass or more, wherein the C ₃ mass ratio of M1 phase to S (M1 _{/ C} 3 S) is 45 mass% or more, high belite-based clinker composition.

The method for producing a high belite clinker composition according to the present invention is prepared by blending 25 to 250 kg of rice husk ash and firing it to produce 1 t of high belite clinker. This is a light clinker manufacturing method.
Preferably, the rice husk ash is used as a SiO ₂ raw material in a cement clinker feed kiln raw material in a ratio of 10 to 100% by mass in the method for producing a high belite clinker composition of the present invention, This is a method for producing a high belite clinker.
The high belite cement composition of the present invention is a high belite cement composition comprising the high belite clinker composition of the present invention and gypsum.

The high belite clinker composition and high belite cement composition of the present invention can be used to combine rice husk ash, which is a waste, without combining various clinker or blending various mixing materials as in the past. In addition, it can be used as a raw material for sending kiln when producing cement clinker, and as a result, the ratio of M1 phase in C ₃ S produced in clinker can be increased to improve the initial strength development, and C ₂ It is possible to increase the hydration activity by increasing the lattice volume of S and to increase the long-term strength development property. Also, the method for producing the high belite clinker composition of the present invention provides the high The belite clinker composition can be easily and economically produced.
Furthermore, it is possible to promote effective utilization of rice husk ash, which has conventionally been waste.

It is a diagram which shows an example of the calcination temperature conditions for manufacturing a clinker. It is a diagram showing an example of a relationship between the mortar strength of C ₃ M1 phase mass ratio of in _S (wt%) and pouring 3 days after the clinker.

The present invention is illustrated by the following preferred examples, but is not limited thereto.
Concrete dams and concrete structures with large member dimensions, so-called mass concrete, are prone to cracking due to thermal stress, and therefore require cement with low heat of hydration and high initial strength and long-term strength, especially high belite. Low heat Portland cement such as cement is used.
On the other hand, there are mainly 4 types of cement, 3CaO.SiO ₂ (C ₃ S), 2CaO · SiO ₂ (C ₂ S), 3CaO · Al ₂ O ₃ (C ₃ A) and 4CaO · Al ₂ O ₃ · Fe _2. O ₃ (C ₄ AF) cement clinker minerals are included, and strength development and hydration exothermic characteristics differ depending on the content of these minerals.

C ₃ S, which is one of the cement minerals, is closely related to the short-term strength development, especially when the amount of C ₃ S contained in the cement is large, the strength development is fast, and conversely, the strength development is slow. , for example, ordinary Portland cement C _{3 S} is about 55 wt%, more strength development early was high-early-strength 65% by weight Portland cement, moderate heat Portland cement with reduced strength development and hydration heat value conversely 40 About 25% by mass of low heat Portland cement is contained.
In addition, C ₂ S, which is one of the cement minerals, has a slower hydration reaction than that of alite. Therefore, in order to increase the long-term strength, it is necessary to increase the hydration activity of C ₂ S.

The high belite clinker composition of the present invention is a high belite clinker composition containing 50 to 70% by mass of C ₂ S, wherein the M1 phase in C ₃ S is 12% by mass or more, and C ₃ The mass ratio (M1 / C ₃ S) of the M1 phase to S is 45% by mass or more, preferably 55% by mass or more.
By adopting such a configuration, the initial strength of the high belite cement can be improved without changing the mineral composition of the clinker, and at the same time, the hydration activity of C ₂ S is enhanced to increase the long-term strength. Is also possible.

Here, the high belite clinker means that the C ₂ S mineral constituting the clinker is contained in an amount of 50 to 70% by mass.
In such a high belite type clinker composition, the M1 phase in C ₃ S to be contained is 12% by mass or more, preferably 14% by mass or more, and the M1 phase is a mass ratio of the M1 phase to C ₃ S. When (M1 / C ₃ S) has a ratio of 45% by mass or more, preferably 55% by mass or more, the initial strength development of the obtained high belite cement composition is increased, and the long-term altitude is also excellent. Can do.

In order to contain the M1 phase in the above ratio in the high belite clinker composition, the production method of the high belite clinker composition of the present invention is to produce rice husk ash in 1 ton of high belite clinker composition. It is prepared by blending 25 to 250 kg and baking.
That is, it is C ₃ S among the above four main types of clinker minerals that greatly affects the initial strength. By changing the ratio of the M 1 phase of C ₃ S with rice husk ash, the initial strength development is increased. together is, the greatest influence on the long-term strength is C _{2 S} out of the four main types of clinker minerals mentioned above, the hydration reaction of C 2 _S, controls the long-term strength by changing the chaff ash Is something that can be done.

Specifically, in producing 1 ton of cement clinker, 25 to 350 kg, preferably 62.5 to 250 kg, more preferably 125 to 250 kg of rice husk ash as a raw material is blended and fired to obtain a cement clinker obtained. The M ₃ phase of C ₃ S can be increased, the α ′ phase of C ₂ S can be increased, and the lattice volume of the β phase of C ₂ S can be further increased, thereby increasing the long-term strength. .
This is because C ₂ S, which was α ′ phase in the baking kiln, is usually mostly transferred to β phase with cooling, but the use of rice husk ash according to the present invention suppresses such transition, and more Many α 'phases are obtained, and the long-term strength is considered to increase. Thereby, the hydration activity can be increased.

The rice husk ash that can be used is not particularly limited, and conventionally used rice husk ash can be used in the present invention.
The rice husk ash is used as a raw material for SiO ₂ feed kiln, which is blended as a feed kiln raw material when producing a cement clinker. This is because the rice husk ash is amorphous silica.
Usually, when producing cement clinker, for example, silica stone is used as the raw material for the SiO ₂ feeding kiln, but some or all of the silica stone usually used as the raw material for SiO ₂ feeding kiln is replaced with the rice husk ash. use.
The ratio replaces 10 to 100% by mass, preferably 10 to 100% by mass, and preferably 60 to 80% by mass of the raw material of the SiO ₂ feeding furnace with rice husk ash.

  The rice husk ash is amorphous silica, but even if silica fume or silica gel, which is other amorphous silica, is used, the effect of the present invention cannot be obtained.

The clinker feeding kiln raw material blended with rice husk ash at the above blending ratio is fired, for example, with an actual machine, and the cement clinker is fired.
Such firing conditions are not particularly limited, and the cement clinker composition is usually produced by firing under conditions for firing cement clinker or any known conditions.
By producing the cement clinker composition in this way, the proportion of the M ₃ phase of C ₃ S produced in the resulting cement clinker composition can be increased, and the hydration activity of C ₂ S can be increased.
By containing the obtained high belite clinker composition and gypsum, the high belite cement composition of the present invention can be obtained.

Thus, according to the present invention, the M1 phase in C ₃ S is prepared by blending and preparing a certain amount of rice husk ash when producing a cement clinker without changing the mineral composition and the specific surface area of the brain. And the C ₂ S lattice volume can be increased, and as a result, the initial strength and the long-term strength can be changed. It can be produced using rice husk ash.

  In addition, since the manufacturing method of the cement of the present invention and the clinker composition of the present invention can modify belite, the low heat Portland cement which is a high belite-containing clinker composition and a high belite-based cement composition and its The present invention can be effectively applied to a production method and the like, but can also be applied to various cement production methods such as ordinary Portland cement and moderately heated Portland cement.

The present invention will be described in detail by the following examples and comparative examples.
Each raw material used for the production of cement clinker is shown in Table 1 below together with the chemical composition.

(Comparative Example 1)
Using the limestone, quartzite, calami, clay (1), clay (2), and quartzite, which are raw materials for portland cement having the composition shown in Table 1, the chemical composition of the obtained Portland cement clinker is as follows: Temperature conditions (adjusted and blended as shown in Table 2, calcined at a firing temperature of 1000 ° C. for 30 minutes, then increased from 1000 ° C. to 15 ° C./min and calcined at 1450 ° C. for 30 minutes ( The Portland cement clinker was prepared by firing in a Kanthal super furnace under the temperature conditions shown in FIG. However, silica was blended at a ratio of 25.0 parts by mass per 100 parts by mass of the obtained Portland cement clinker.

Dihydrogypsum was added to the obtained Portland cement clinker and pulverized by an actual machine finishing mill to obtain a low heat Portland cement which is a high belite-containing cement having an average brain specific surface area of 3700 cm ² / g.
The gypsum was added so that the amount of SO ₃ contained in the obtained Portland cement was 2.4% by mass.
CaO, SiO ₂ , Al ₂ O ₃ and Fe ₂ O ₃ contained in the obtained Portland cement were analyzed according to JIS R 5202 “Chemical analysis method of Portland cement”, and C ₃ S, C using the Borg formula. ₂ S, C ₃ A, and C ₄ AF were calculated (Borg mineral composition).
The results are shown in Table 3 below, including the amount of SO ₃ (gypsum) analyzed in JIS R 5202 “Chemical analysis method for Portland cement”.

(Comparative Example 2)
In addition to replacing 5% by mass (corresponding to 1.25 parts by mass per 100 parts by mass of the obtained clinker) of the silica used in Comparative Example 1 in producing the Portland cement clinker, with rice husk ash shown in Table 1, In the same manner as in Comparative Example 1, a Portland cement clinker was produced, and further Portland cement was prepared.

Example 1
A comparative example except that 10% by mass (corresponding to 2.5 kg per 100 parts by mass of the obtained clinker) of silica used in the comparative example 1 in producing the Portland cement clinker was replaced with rice husk ash shown in Table 1. As in Example 1, a Portland cement clinker was produced, and further Portland cement was prepared.

(Example 2)
A comparative example except that 25% by mass (corresponding to 6.25 kg per 100 parts by mass of the obtained clinker) of silica stone used in Comparative Example 1 for producing Portland cement clinker was replaced with rice husk ash shown in Table 1. As in Example 1, a Portland cement clinker was produced, and further Portland cement was prepared.

(Example 3)
In addition to replacing 50% by mass (corresponding to 12.5 parts by mass per 100 parts by mass of the obtained clinker) of silica used in Comparative Example 1 in producing the Portland cement clinker, with rice husk ash shown in Table 1, In the same manner as in Comparative Example 1, a Portland cement clinker was produced, and further Portland cement was prepared.

Example 4
Comparative Example 1 except that the total amount of silica stone used in Comparative Example 1 for producing Portland cement clinker (corresponding to 25.0 parts by mass per 100 parts by mass of the clinker obtained) was replaced with rice husk ash shown in Table 1. In the same manner as above, Portland cement clinker was produced, and Portland cement was further prepared.

(Comparative Example 3)
Comparative Example 1 except that the total amount of silica used in Comparative Example 1 (corresponding to 25.0 parts by mass per 100 parts by mass of the obtained clinker) was replaced with silica gel shown in Table 1 in producing Portland cement clinker. In the same manner, Portland cement clinker was produced, and further Portland cement was prepared.

(Comparative Example 4)
Comparative Example 1 except that the total amount of silica stone used in Comparative Example 1 for producing Portland cement clinker (corresponding to 25.0 parts by mass per 100 parts by mass of clinker obtained) was replaced with silica fume shown in Table 1. In the same manner as above, Portland cement clinker was produced, and Portland cement was further prepared.

(Test example)
Each clinker and each cement obtained in Examples 1 to 4 and Comparative Examples 1 to 3 were evaluated by the following test, and the results obtained are shown in Table 4 below.
(Test Example 1)
Each clinker obtained was measured for f-CaO in the clinker according to JCAS I-01. It should be noted that f-CaO is generally used as an index for judging good / bad firing, and if it is 1% by mass or less, firing is judged as “good”.

(Test Example 2)
Each obtained clinker was ground using a planetary mill PM-400 (manufactured by Retsch) at 300 rpm for 20 minutes until the brain value was about 6000 cm ² / g to prepare a test sample. Each test sample was measured for a diffraction peak at a tube current of 40 mA and a tube voltage of 45 kV using a powder X-ray diffractometer X'Pert MPD (manufactured by Panalical), and then subjected to Rietveld analysis with the analysis software High Score Plus manufactured by the same company. go to, _{C 3} S amount (mass%) of the M1 phase crystal phase, M1 phase ratio in the _{C 3} S (wt%) and, to measure the lattice volume of .beta.c ₂ S, Table 4 and the results As shown in FIG.

(Test Example 3)
About each obtained cement, according to JISR5201 "the physical test method of cement", water was added so that water / cement ratio might be 50 mass%, and each mortar was prepared.
The mortar strength of each obtained mortar was measured in accordance with JIS R 5201 “Cement physical test method”, and the strength after 3 days, 7 days, 28 days, and 91 days after each mortar was measured. Table 4 shows.

From the results of Table 4 and FIG. 2, Examples 1 to 4 containing rice husk ash in 2.5 parts by mass to 25 parts by mass in 100 parts by mass of the clinker raw material are M ₃ of C ₃ S in the high belite clinker. It can be seen that the phase is 12% by mass or more and the M1 phase of C3S has (M1 / C ₃ S) of 45% by mass or more, thereby increasing the lattice volume of βC ₂ S. Accordingly, the initial strength of the mortar strength of the mortar obtained is increased, while the long-term strength is also increased. On the other hand, in Comparative Examples 3 and 4 using silica gel or silica fume, which is the same amorphous silica as rice husk ash, it is found difficult to increase the strength of the mortar.
Thus, by incorporating a rice hull ash which is amorphous silica gel at a constant rate, by the production of cement clinker, high α'C 2 _S of hydrous activity often generates, also grating .beta.c 2 _S The volume also increases, and as a result, the desired long-term strength of the cement can be developed.

  The cement obtained by the present invention is excellent in long-term strength, and can be usefully applied to civil engineering and construction fields in which cement is used, particularly concrete dams and concrete structures having a large member size, so-called mass concrete.

Claims (4)

A high belite-based clinker composition comprising 50 to 70 wt% of C ₂ S,
A _high belite clinker composition, wherein the M1 phase in C ₃ S is 12% by mass or more, and the mass ratio of the M1 phase to C ₃ S (M1 / C3S) is 45% by mass or more. 2. The method for producing a high belite clinker composition according to claim 1, wherein the production of 1 t of the high belite clinker composition is performed by blending 25 to 250 kg of rice husk ash and baking the mixture. 3. The method for producing a high belite clinker composition according to claim 2, wherein the rice husk ash is used at a rate of 10 to 100% by mass as a SiO ₂ raw material in a cement clinker feed kiln raw material. A method for producing a light clinker composition. A high belite cement composition comprising the high belite clinker composition according to claim 1 and gypsum.

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