KR20010013108A - Cement clinker and cement containing the same - Google Patents

Abstract

An improvement in cement used for mass concrete, high-strength concrete, high-fluidity concrete, noncontractive concrete and high-durability concrete in the fields of civil engineering and construction, and for building materials manufactured by extrusion molding and sheet making. When the ratio of A1 2 O 3 to Fe 2 O 3 in the cement clinker is regulated to a value of 0.05-0.62, the strength of high-strength and high-fluidity concrete can be further improved, and the heat of hydration can be minimized as the fluidity improving performance and long term strength of the cement are maintained

Description

Cement Clinker and Cement Containing Cement Clinker {CEMENT CLINKER AND CEMENT CONTAINING THE SAME}

At the same time, the rationalization and vitalization of construction and construction technologies have been promoted, and the demand for cement has been diversified and compounded, and the application to high strength and high flow large concrete for high-rise reinforced concrete structures and steel pipe-filled concrete (CFT) structures, etc. In addition, the application of so-called mass concrete, such as concrete dams and concrete structures with large member sizes, has been made.

In order to increase the strength of the concrete, it is necessary to reduce the water cement ratio. As a result, the viscosity of the concrete is increased, the fluidity is impaired, and further, there is a problem that the workability is deteriorated, such as poor pump pressure.

In addition, the reduction in the water cement ratio causes an increase in the amount of cement, and as a result, the amount of heat generated during the hydration reaction also increases, and furthermore, the strength developability in the real structure is received due to the high temperature thermal history. There is also a problem of deterioration.

Because of this problem, usually when Portland cement is used in the construction of high-rise reinforced concrete structures or steel-filled concrete structures, the design reference strength is generally less than 45 N / mm2, but can not be used. That is, in order to achieve a design reference strength of 60 N / mm 2, it is necessary to lower the water concrete ratio to about 30%. As a result, the viscosity of the concrete is significantly increased and the fluidity is impaired, which makes pump pumping difficult.

In addition, in the case of using a mixed cement, the viscosity of concrete is lowered at the same water cement ratio than that of ordinary portland cement. However, since the strength expression property is inferior to that of the ordinary bolt cement, the water strength is higher than that of the ordinary portland cement. It is necessary to reduce the cement ratio, and as a result, the viscosity of the concrete increases and fluidity cannot be ensured, and as a result, only the same strength as that of ordinary Portland cement can be used.

On the other hand, in the case of low-heated Portland cement, the viscosity of concrete is lowered and the strength expression is equal at the same water cement ratio than that of ordinary Portland cement. Therefore, a higher strength region than the ordinary Portland cement, specifically, the design reference strength of about 60 N / mm2 Up to the pump can be pumped.

In addition, the use of low heat Portland cement is also preferable from the viewpoint of reducing the amount of hydration calorific value.

However, even when this low-heat Portland cement is used, the viscosity is not sufficiently reduced, and when the design reference strength is high to about 80 N / mm 2 (about 25% by water cement ratio), the viscosity increases markedly. The furnace cannot be pumped, and the model and pumping conditions of the pump are limited.

In addition, low-heat Portland cement has a problem that the initial strength is lower than that of ordinary Portland cement or blast furnace cement. In order to solve this problem, the powder strength for initial strength improvement is increased, and the amount of SO3 is also increased.

However, the increase in the powder level and the increase in the amount of SO 3 contribute to the improvement in strength, but there is a problem in that the amount of hydration heat is increased and the fluidity of cement is lowered.

In any case, in order to further increase the strength of the high-strength and high-flow concrete, the fluidity of the entire cement-containing binder is improved, and the unit quantity is further reduced, while the fluidity of the concrete is maintained. It is necessary to suppress the amount of hydration heat generated by the whole binder and to improve the strength developability of the binder.

However, fluidity and strength are inherently opposite, and there is a relationship that when one side is improved, the other side is lowered. Therefore, it is not easy to solve these two problems at the same time. In addition, even the problem of lowering the amount of hydration calories is difficult to be achieved, and it has been difficult in the prior art to solve all of these problems.

In addition, various high-flow concrete and high-strength concrete have been used in recent years, but the concrete has a state of excellent properties, while the self-shrinkage of the concrete (volume reduction occurs after the start of condensation due to the hydration reaction of cement) occurs. There is a problem that increases).

On the other hand, in the case of concrete having a large member cross section, the heat of hydration of cement accumulates near the center thereof, and the internal temperature rises, and during the ascending or cooling process, between the outside (part of contact with the outside air) and the interior of the poured concrete Significant temperature differences occur and partial deformation occurs, so-called temperature cracking is likely to occur.

When the occurrence of such a temperature crack is foreseen, it is necessary to treat it as mass concrete in design and construction.

Although there are many ways to prevent temperature cracking in mass concrete, it is most effective and economical to use cement having a small calorific value.

As cement having a low calorific value, there are mixed cements in which Portland cement has mixed blast furnace slag powder and / or fly ash in a large amount, but the initial strength is low and the mold is poor in demoulding. There is a problem such as inferior durability.

In order to solve this problem, a low heat Portland cement is used, but there is a problem that the effect of suppressing temperature cracking is not sufficient because the low heat Portland cement does not sufficiently reduce the calorific value.

Moreover, also in mass concrete, there exists a problem of self-shrinkment as mentioned above. In other words, there have been reported cases of cracking that cannot be explained only by the factors caused by the temperature difference as described above, and it has been pointed out that self-shrinkage may greatly affect the occurrence of cracking.

The present invention relates to a cement clinker and a cement containing the cement clinker, and more specifically, to a civil engineering, construction field, extrusion molding, and construction of high strength and high flow concrete, mass concrete, non-concrete concrete, and high durability concrete. It is related with the improvement of the cement used for building materials by).

1 is a graph showing the relationship between IM and hydration heat / mortar compressive strength (about 15% by weight of C ₃ S).

Fig. 2 is a graph showing the relationship between IM and hydration heat / mortar compressive strength (about 35% by weight of C ₃ S).

3 is a graph showing the relationship between IM and hydration heat / mortar compressive strength (about 55% by weight of C ₃ S).

4 is a graph showing the relationship between the IM and the mortar flow (about 15% by weight of C ₃ S).

5 is a graph showing the relationship between the IM and the pat area (about C ₃ S 15% by weight).

6 is a graph showing the relationship between the IM and the mortar flow (about 35% by weight of C ₃ S).

7 is a graph showing the relationship between the IM and the pad area (about 35% by weight of C ₃ S).

8 is a graph showing the relationship between the IM and the mortar flow (about 55% by weight of C ₃ S).

9 is a graph showing the relationship between the IM and the pad area (about C ₃ S 55 wt%).

Fig. 10 is a graph of the measurement result of the amount of self shrinkage.

In order to further increase the strength of high strength and high flow concrete, an object of the present invention is to simultaneously achieve the problems of improving the flowability of cement and suppressing the heat of hydration while maintaining the strength for a long time.

Another object of the present invention is to provide a cement for high strength and high flow concrete, which exhibits high fluidity and low viscosity with a low water cement ratio, high strength expression even when a heat history is received, and also has low self-shrinkage.

A further object of the present invention is to provide a cement for mass concrete which is excellent in the effect of suppressing cracking due to temperature cracking and self-shrinkage.

In order to achieve the above object, the present invention is characterized in that Al ₂ O ₃ and Fe ₂ O ₃ in the cement clinker are 0.05 to 0.62 in an Al ₂ O ₃ / Fe ₂ O ₃ ratio.

3CaO · Al ₂ O ₃ (hereinafter referred to as C ₃ A) in cement is known to have high hydration reactivity, high hydration calorific value, and high self shrinkage, and moderate heat Portland cement or low heat Portland. When producing cement, C ₃ A is usually reduced from about 9% by weight of Portland cement to about 2 to 4% by weight.

When the Al ₂ O ₃ / Fe ₂ O ₃ ratio of the cement clinker (hereinafter referred to as IM) is around 0.62, the gap quality when calculated by vogue is only ferrite (C ₄ AF). And C ₃ A does not generate computationally.

In addition, by lowering IM, the gap is changed to ferrite of C ₆ AF ₂ or C ₂ F composition.

As a result, it is possible to improve fluidity and reduce self-shrinkage by eliminating C ₃ A, which has a high hydration reactivity, high hydration calorific value, and a large amount of adsorption of admixture when it is in concrete, and which has the largest self shrinkage. do.

In addition, as the composition of the ferrite changes from C ₄ AF to C ₆ AF ₂ due to the reduction of IM, the amount of heat of hydration of cement decreases and fluidity improves.

In addition, since C ₄ AF has a larger self shrinkage after C ₃ A, and C ₆ AF ₂ has a smaller self shrinkage, the self shrinkage is further reduced by the composition change as described above.

As described above, it has been clarified by the present invention that the change of the ferrite composition by reducing the IM of the cement clinker is an effective means for solving the problem, beyond the effect of simply removing C ₃ A.

In addition, because the gap was insufficient in the extension of the mortar compressive strength as ferrite (near IM = 0) of the C ₂ F composition, the lower limit of the IM was set to 0.05. This is in addition to the effect of the change of the high content of the trace constituents to 2CaO.SiO ₂ (hereinafter referred to as C ₂ S), and the amount of Al ₂ O ₃ in the cement clinker is reduced, thereby determining the C ₂ S crystal. This is large, and C ₂ S is crushed in the crushing process to cement is considered one of the causes.

In the present invention, the content of C ₂ S is preferably in the range of 35 to 75% by weight.

If the content of C ₂ S in the cement clinker is less than 35% by weight, the content of C ₃ S is relatively high, and the amount of heat generated by the concrete is increased, resulting in a decrease in strength expression when a thermal history is received, and compared with low heat Portland cement. The specific strength (the strength per 1 ℃ of insulation temperature rise) of concrete's insulation temperature rise does not become large.

On the contrary, when it exceeds 75% by weight, the strength expression rate is inferior, and predetermined strength is not obtained. In addition, compared with the low heat Portland cement, the thermal insulation temperature rise ratio of the concrete is not increased.

The adiabatic temperature increase ratio strength of this concrete becomes an index of resistance corresponding to the temperature cracking of the concrete.

The resistance corresponding to the temperature cracking of the concrete becomes so large that the ratio of tensile strength / generated stress of the concrete becomes large.

In other words, if the strength is the same, as the generated stress is smaller, and if the generated stress is the same, the resistance corresponding to the temperature crack becomes larger as the tensile strength is larger.

In addition, the generated stress is increased when the heat generation amount of the concrete, if all the conditions of the structure are the same.

Although detailed evaluation of the temperature crack resistance of concrete needs to be carried out by temperature stress analysis using the finite element method, etc., in comparison with the temperature crack resistance of the concrete itself, the strength (compression) per 1 ° C. of the thermal insulation temperature rise is simple. Is used as an index.

This is because tensile strength is correlated with compressive strength.

In the present invention, in the cement composition containing Al ₂ O ₃ and Fe ₂ O ₃ in a cement composition containing a cement clinker having a ratio of 0.05 to 0.62 in an Al ₂ O ₃ / Fe ₂ O ₃ ratio, the ply having a particle diameter of 20 μm or less It is also possible that the ash is blended from 2 to 25% by weight.

When a fly ash is mix | blended, the particle diameter shall be 20 micrometers or less because when a particle diameter is 20 micrometers or less, a fly ash will fill between cement particles, and a fluidity will improve without a viscosity increase by a filler effect.

Moreover, when the compounding quantity of fly ash was 2-25 weight%, when the compounding quantity of fly ash is less than 2 weight%, sufficient filler effect will not be acquired, On the contrary, when it exceeds 25 weight%, intensity | strength expression speed will be delayed and predetermined This is because the strength of is not obtained.

In addition, for such a fly ash, it is also possible to blend 10 to 60% by weight of the blast furnace slag powder having a brain specific surface area of 5000 to 10000 cm 2 / g.

If the brain specific surface area of the blast furnace slag powder is 5000 cm 2 / g or more, the blast furnace slag is filled between the cement particles and the viscosity is improved without increasing the viscosity due to the filler effect, while when it exceeds 10000 cm 2 / g, it is prescribed in concrete. The amount of dispersant used to obtain the high mobility becomes very large and it is not economical.

On the other hand, if the blending amount of the blast furnace slag powder is less than 10% by weight, a sufficient filler effect is not obtained. On the contrary, if it exceeds 60% by weight, the strength expression rate is slowed, and the predetermined strength is not obtained.

In addition, in this invention, it is also possible to mix | blend a dispersing agent.

The dispersant is used for the purpose of dispersing the cement particles at a low water cement ratio to secure the fluidity by reducing the yield value of the cement paste, and the composition thereof is not particularly limited as long as it can disperse the cement particles. You can use either a high performance water reducer or a high performance AE water reducer.

When the cement of the present invention is applied to high strength and high flow concrete, the mixing of cement, water, aggregate, and dispersant is not particularly limited, but the high strength and high flow rate of water cement ratio of 30% or less that significantly increases the viscosity of concrete is increased. It is most effective when applied with concrete.

As described above, in the present invention, since the clinker composition is set to 0.05 to 0.62 in the Al ₂ O ₃ / Fe ₂ O ₃ ratio, the problem that has not been solved conventionally is that the flow of cement and the hydration heat are suppressed while maintaining the strength for a long time. To solve at the same time. As a result, it is possible to solve the problems of the conventional low-heat Portland cement and the case of adding fly ash, and to provide a high strength and high flow concrete composition.

In addition, it is possible to obtain high strength and high flow concrete with low water concrete ratio, high fluidity and low viscosity, and high strength expression even when a thermal history is received.

As a result, even high strength and high flow concrete having a design reference strength of about 80 N / mm 2 can be constructed without any limitation on the type of pump or the pumping condition, and the aggregate that can be used is also not limited. High strength and high flow concrete can be manufactured.

In addition, the amount of self-shrinkage can be reduced, the occurrence of cracks due to self-shrinkage can be prevented, and the durability can be improved, and high functionalization as high strength and high flow concrete can be promoted.

In addition, in the mass concrete structure, the resistance corresponding to temperature cracking is improved, and reduction, which is another temperature cracking countermeasure commonly used in combination, becomes possible, and it is possible to economically reduce temperature cracking.

EMBODIMENT OF THE INVENTION Hereinafter, the Example of this invention is described.

Test Example 1

The raw materials of the cement clinker were combined using a reagent, and after firing at 1450 ° C. for one hour in an electric furnace, they were extracted from the electric furnace and quenched in air, and the clinkers of the compositions of Examples 1 to 12 shown in Tables 1 to 3, and Comparative Examples The clinker of the composition of 1-9 was obtained.

Table 1

Chemical composition of clinker (% by weight) SiO ₂ Al ₂ O ₃ Fe ₂ O ₃ CaO MgO Na ₂ O Comparative Example 1 28.0 4.2 2.4 63.5 1.0 0.38 Comparative Example 2 27.6 3.8 3.5 63.4 1.0 0.36 Example 1 28.0 2.9 4.7 62.7 1.0 0.40 Example 2 27.9 2.3 5.4 62.5 1.0 0.42 Example 3 27.9 1.3 6.8 62.3 1.0 0.38 Example 4 27.7 0.5 7.9 62.0 1.0 0.40 Comparative Example 3 27.8 0.1 8.3 61.7 1.0 0.52

TABLE 2

Chemical composition of clinker (% by weight) SiO ₂ Al ₂ O ₃ Fe ₂ O ₃ CaO MgO Na ₂ O Comparative Example 4 25.4 4.7 2.7 65.0 1.2 0.40 Comparative Example 5 25.3 4.0 4.0 64.4 1.2 0.39 Example 5 25.5 3.2 5.2 63.9 1.2 0.38 Example 6 25.5 2.6 6.9 63.7 1.2 0.41 Example 7 25.5 1.5 7.5 63.3 1.2 0.42 Example 8 25.4 0.5 8.9 63.0 1.2 0.37 Comparative Example 6 25.5 0.2 9.3 61.9 1.2 0.43

TABLE 3

Chemical composition of clinker (% by weight) SiO ₂ Al ₂ O ₃ Fe ₂ O ₃ CaO MgO Na ₂ O Comparative Example 7 23.5 5.1 2.9 66.3 1.3 0.36 Comparative Example 8 23.6 4.2 4.3 65.7 1.3 0.42 Example 9 23.7 3.3 5.4 65.3 1.3 0.38 Example 10 23.8 2.7 6.2 65.1 1.3 0.40 Example 11 23.7 1.7 7.6 64.8 1.3 0.43 Example 12 23.7 0.6 9.0 64.3 1.3 0.38 Comparative Example 9 23.5 0.2 9.6 64.5 1.3 0.41

Gypsum was added to the clinker of the compositions of Examples 1 to 12 and Comparative Examples 1 to 9 so as to be 2% by weight in terms of SO ₃ , and mixed and pulverized in a test grinder, thereby varying the amount of C ₃ S and IM. 21 kinds of cement were adjusted.

The mineral composition is shown in Tables 4-6.

Table 4

Mineral composition (% by weight) IM C ₃ S C ₂ S Comparative Example 1 14 70 1.75 Comparative Example 2 18 66 1.09 Example 1 16 68 0.62 Example 2 17 67 0.43 Example 3 16 68 0.19 Example 4 17 67 0.06 Comparative Example 3 16 68 0.01

Table 5

Mineral composition (% by weight) IM C ₃ S C ₂ S Comparative Example 4 36 46 1.74 Comparative Example 5 37 44 1.00 Example 5 37 45 0.62 Example 6 37 45 0.43 Example 7 36 46 0.20 Example 8 36 46 0.06 Comparative Example 6 35 47 0.02

Table 6

Mineral composition (% by weight) IM C ₃ S C ₂ S Comparative Example 7 53 27 1.76 Comparative Example 8 54 27 0.98 Example 9 55 26 0.61 Example 10 54 27 0.44 Example 11 54 27 0.22 Example 12 53 28 0.07 Comparative Example 9 56 25 0.02

The powder degree of cement was 2900-3000 cm <2> / g in the brain specific surface area.

About the clinker of the said Examples 1-12 and Comparative Examples 1-9, the heat of hydration and the mortar compressive strength were measured, and the ratio was computed.

The heat of hydration was measured based on R5203-1995 of JIS.

In addition, the mortar compressive strength was measured based on R5201-1992 of JIS.

The measurement results are shown in Tables 7 to 9.

TABLE 7

Table 8

Table 9

As is clear from Tables 7 to 9, in Examples 1 to 12, the ratio of the heat of hydration / mortar compressive strength was smaller than that of Comparative Examples 1 to 9, and the effect of suppressing the generation of hydration heat was recognized.

In particular, age (材齡) the ratio of the 13 state, and heat of hydration / mortar compression of the year strength, Figs. 1 to, as shown in 3, C ₃ S amount is 15 wt% and 35 wt% or so, and about 55% by weight In any case, IM became small within the range of 0.05 to 0.62.

In addition, the flow and the pad area were measured for Examples 1-12 and Comparative Examples 1-9.

(Measuring method of plastic area)

The paste was adjusted by putting 200 g of cement in about 10 second in the middle of 200 ml of beakers containing 70 ml of mixed water containing a water reducing agent, and mixing by hand mixer at intervals of 1 minute and 50 seconds.

The paste was poured into the mini slump cone on the plastic sheet, and the paste in the mini slump cone was mixed well with the microspectra, the top was evened out, and the mini slump cone was pulled up after 3 minutes at the start of cement injection.

The short and long diameters of the paste expanded on the plastic sheet were measured, and the pad area was calculated.

(Measuring method of flow)

The flow value was measured based on R5201-1992 of JIS.

That is, the sample is bound in this layer to a flow cone installed at a central position on the flow table where the sample is well drawn on a dry cloth. In each layer, the tip of the stick sticks to a depth of about 1/2 of its side, each of the 15 sticks across the entire surface, and eventually evens out the surface that made up the shortfall.

After binding, remove the flow cone upwards, give 15 drop motions in 15 seconds, measure the diameter after the sample is enlarged to the maximum, and in the direction perpendicular to this, measure the average value in mm It expressed by the integer made into units and made this the fluid value.

The measurement results are shown in Tables 10 to 12.

Table 10

Table 11

Table 12

In Table 10, Examples 1-4 and Comparative Examples 1-3, ie, the results regarding the belite cement of about 15% by weight of C ₃ S amount were shown.

Although the mortar flow and the pad area were both enlarged within the range of IM 0.05 to 0.62, this is clearly shown by FIGS. 4 to 5.

In particular, Table 11, showed Examples 5 to 8 and Comparative Examples 4 to 6, that is a result of the C ₃ S in the moderate heat cement type in the low heat of about 35% by weight amount.

Results of Table 11 (Even when the amount of C ₃ S is about 35% by weight, as shown in FIGS. 6 and 7, both the mortar flow and the pad area become large within the range of IM 0.05 to 0.62. Significantly increased near IM 0.62. Thus, in Examples 5 to 8 and Comparative Examples 4 and 5, it was markedly different from each other.

In addition, the results of the normal cement type of about 55% by weight of C3S are shown in Examples 9 to 12 and Comparative Examples 7 to 9 of Table 12.

Also in the results of Table 12 (when the amount of C ₃ S is about 55% by weight), as shown in FIGS. 8 and 9, both the mortar flow and the pad area are large within the range of IM 0.05 to 0.62, and the pad area is near IM 0.62. Markedly increased. Thus, in Examples 9 to 12 and Comparative Examples 7, 8 were found to be significantly different from each other.

Test Example 2

Using materials consisting of cement, thin aggregate, coarse aggregate, admixture, and water, two-axes concrete with a water cement ratio of 30, 25, 20% and unit quantity of 175㎏ / ㎥ is kneaded with a mixer and kneaded with a mixer. Appearance viscosity was measured by the two-point method using, and compressive strength was measured by JIS A 1108.

In addition, regarding the concrete having a water cement ratio of 30%, a unit quantity of 175 kg / m3 and a unit cement amount of 580 kg / m3, the method of self-shrinkment and self-expansion of cement paste, mortar, and concrete, ) Was measured.

As cement in the materials used, the mineral composition was ground by adding 1.0% of gypsum in terms of SO ₃ to seven types of clinkers (Examples 13 to 16 and Comparative Examples 10 to 12) as shown in Table 13. It was used.

The powder degree of cement was 3100-3300 cm <2> / g in the brain specific surface area.

As the thin aggregate, one having a specific gravity of 2.59 was used as Yajucheon-san river sand.

In addition, as coarse aggregate, the thing with specific gravity 2.70 was used as high silicate crushed stone.

In addition, as the dispersant, FP300UB (manufactured by FPK), which is a high-performance AE supernatant, was used, and the added amount thereof was an amount such that the slump flow value of concrete was 60 ± 5 cm.

Water used tap water.

The test results are shown in Table 13 and FIG.

As is also clear from Table 13, in the case of Comparative Example 10 and Comparative Example 11 in which the IM exceeds 0.62, the decrease in the external viscosity is insufficient, but in Examples 13 to 16 and Comparative Example 12 in which the IM is 0.62 or less, It was found that the apparent viscosity was significantly lowered.

On the other hand, in the case of the comparative example 3 whose IM is less than 0.06, it turned out that it is inferior to intensity expression.

In addition, as is apparent from FIG. 10, in the case of Comparative Examples 10 and 11 in which the IM is greater than 0.62, the self-shrinkage is remarkable. It became.

Table 13

Test Example 3

Using cement, thin aggregate, coarse aggregate, admixture, and water, two-bit concrete with 25% water cement ratio and 175 kg / m3 unit quantity is forcibly kneaded with a mixer and kneaded using a mixer. Was measured.

As cement in the material used, the mineral composition was ground by adding 1.0% of gypsum in conversion of SO ₃ to five types of clinkers (Examples 17 to 19 and Comparative Examples 13 to 14) as shown in Table 14. It was used.

The powder degree of cement was 3100-3300 cm <2> / g in the brain specific surface area.

As the thin aggregate, one having a specific gravity of 2.59 was used as Yajucheon-san river sand.

In addition, as coarse aggregate, the thing with specific gravity 2.70 was used as high silicate crushed stone.

Furthermore, as the dispersant, Maitei 3000S (manufactured by Huawang Co., Ltd.), which is a high-performance AE supernatant, was used, and the amount thereof was set to an amount such that the slump flow of the concrete was 60 ± 5 cm.

Water used tap water.

The curing of specimens for compressive strength test was carried out in a foamed Schiropol container with a thickness of 10 cm in order to confirm the strength when subjected to standard curing in water at 20 ° C and thermal history. Was added, and two kinds of the simple thermal curing which filled the foamed Styropol beads (space).

In the simple thermal curing, the concrete temperature was also measured using a thermocouple.

The test results are shown in Table 14.

Table 14

As is also clear from Fig. 14, there is no problem in Examples 17 to 19 and Comparative Example 14 in which the content of 2CaO.SiO ₂ is 35% by weight or more, but in the case of Comparative Example 13 which is less than 35% by weight, it is relatively 3CaO. It was found that the SiO ₂ content was not high and the strength developability in the case of receiving a thermal history was lowered.

On the other hand, in the case of Comparative Example 14 in which the content of 2CaO.SiO ₂ exceeds 65% by weight, it was found that the strength expression was remarkably slowed down.

Test Example 4

Using cement, thin aggregate, coarse aggregate, dispersant, and water, two-axes concrete with 50% water cement, 175 kg / m3 unit quantity, and 350 kg / m3 unit cement volume is kneaded using a mixer to knead. The amount of increase in heat insulation temperature was measured using an air circulation type heat insulation temperature increase test apparatus, and the compressive strength was measured according to JIS A 1108.

As the cement used in the material, the mineral composition was ground by adding 1.0% of gypsum in conversion of SO ₃ to seven kinds of clinkers (Examples 20 to 23 and Comparative Examples 15 to 17) as shown in Table 15. It was used.

The powder degree of cement was 3100-3300 cm <2> / g in the brain specific surface area.

As the thin aggregate, one having a specific gravity of 2.59 was used as Yajucheon-san river sand.

In addition, as coarse aggregate, the thing with specific gravity 2.70 was used as high silicate crushed stone.

In addition, as a dispersant, Pozoris NO. 70 (made by NMB) was used and the addition amount was 0.25 weight% of cement.

Water used tap water.

The test results are shown in Table 15.

As is clear from Table 15, in the case of Examples 20 to 23 in which the IM is 0.05 or more and 0.62 or less, the thermal insulation temperature increase decreases and the thermal insulation temperature rise does not interfere with the strength expression property by the IM reduction. It has been found that the specific strength increases.

On the other hand, in the case of the comparative example 17 in which IM is less than 0.05, since intensity expression property falls, it turned out that the thermal insulation temperature rising ratio becomes low by the 28th day.

On the other hand, in the case of the comparative example 15 and the comparative example 16 which IM exceeds 0.62, the heat insulation temperature rise amount became large.

Table 15

Test Example 5

Using cement, thin aggregate, coarse aggregate, dispersant, and water, two-axes concrete with 50% water cement, 175 kg / m3 unit quantity, and 350 kg / m3 unit cement volume is kneaded using a mixer to knead. The amount of increase in heat insulation temperature was measured using an air circulation type heat insulation temperature increase test apparatus, and the compressive strength was measured according to JIS A 1108.

As cement in the material used, the mineral composition was ground by adding 1.0% of gypsum in conversion of SO ₃ to five types of clinkers (Examples 24 to 26 and Comparative Examples 18 to 19) as shown in Table 16. It was used.

The powder degree of cement was 3100-3300 cm <2> / g in the brain specific surface area.

As the thin aggregate, one having a specific gravity of 2.59 was used as Yajucheon-san river sand.

In addition, as coarse aggregate, the thing with specific gravity 2.70 was used as high silicate crushed stone.

In addition, as a dispersant, Pozoris NO. 70 (made by NMB) was used and the addition amount was 0.25 weight% of cement.

Water used tap water.

The test results are shown in Table 16.

Table 16

As is clear from Table 16, in the case of Comparative Example 18 in which the content of 2CaO.SiO ₂ is less than 45 wt% even if IM is 0.2, the strength expression rate is faster, but the increase in heat insulation temperature is also increased. The upward strength was found to be low.

In contrast, in the case of Comparative Example 19 in which the content of 2CaO.SiO ₂ is more than 75% by weight, the heat insulation temperature rise is small, but the strength expression rate is slowed down, so that the heat insulation ratio is significantly remarkable at 7 days. It turned out to fall.

Test Example 6

Using concrete composed of cement, thin aggregate, coarse aggregate, dispersant, and water, the concrete having a water cement ratio of 30%, a unit quantity of 175 kg / m 3, and a unit cement amount of 580 kg / m 3 was described by the Japan Concrete Institute. Self-shrinkage amount was measured by the method of self-shrinkage and self-expansion of cement paste, mortar, and concrete.

As the cement used in the material, the mineral composition was ground by adding 1.0% of gypsum in conversion of SO ₃ to seven kinds of clinkers (Examples 20 to 23 and Comparative Examples 15 to 17) as shown in Table 15. It was used.

The powder degree of cement was 3100-3300 cm <2> / g in the brain specific surface area.

As the thin aggregate, one having a specific gravity of 2.59 was used as Yajucheon-san river sand.

In addition, as coarse aggregate, the thing with specific gravity 2.70 was used as high silicate crushed stone.

Moreover, as a dispersing agent, FP300UB (made by FPK) which is a high performance AE water reducing agent was used, and the addition amount made it the quantity which the slump flow of concrete became 60 +/- 5 cm.

Water used tap water.

The test results are shown in FIG.

As is also clear from FIG. 10, in the case of Comparative Examples 15 and 16 in which the IM is greater than 0.62, self contraction is remarkable. However, in Examples or Comparative Examples 17 in which the IM is 0.62 or less, the amount of self contraction is significantly reduced. It turned out.

However, in the case of the comparative example 17, it is as having demonstrated in test example 4 that intensity | strength developability falls.

(Test Example 7)

In Example 15, C _{3 S} 36% by weight, C ₂ S46% by weight, and IM of 0.20 were used, the steel cement ratio of 20% and unit quantity of 175 kg / m 3 were subjected to two-axes hardening of the concrete, using a mixer. The mixture was kneaded, the apparent viscosity was measured by a two-point method using a rotational viscometer, and the compressive strength was measured by JIS A 1108.

As the thin aggregate, one having a specific gravity of 2.59 was used as Yajucheon-san river sand.

In addition, as coarse aggregate, the thing with specific gravity 2.70 was used as high silicate crushed stone.

Moreover, as a dispersing agent, FP300UB (made by FPK) which is a high performance AE water reducing agent was used, and the addition amount made it the quantity which the slump flow of concrete becomes 60 +/- 5 cm.

Water used tap water.

In addition, the following three types were used as fly ash.

① Non-classified products (JIS products)

②30㎛ classification

③20㎛ classification

As the blast furnace slag fine powder, the following three types were used.

④ A brain specific surface area of about 4500 cm2 / g

⑤ It has a brain specific surface area of about 5000cm2 / g

⑥ Brain specific surface area of about 10000㎠ / g

The kind and the mixing ratio of the mixed material were changed into Examples 27-35 and Comparative Examples 20-32 as follows.

It was not mixed admixture. Comparative Example 20

[In case of mixed ash fly ash]

① Comparative example 21 which mixes non-classified goods 10%

20% Mixed Comparative Example 22

② Comparative Example 23 for mixing 10 µm classified product with 10%

20% mixed comparative example 24

③ Comparative example 25 of mixing 20 micrometer classification goods 1%

2% Mixed Example 27

15% Mixed Example 28

25% Mixed Example 29

30% Mixed Comparative Example 26

④ Brain specific surface area about 4500㎠ / g

10% mixture comparative example of thing

30% mixed comparative example 28

⑤ About 5000 ㎠ / g of brain specific surface area

5% mixture comparative example of thing

10% Mixed Example 30

30% Mixed Example 31

60% Mixed Example 32

70% mixed comparative example 30

⑥ Brain specific surface area about 10000㎠ / g

5% mixture comparative example of thing

10% Mixed Example 33

30% Mixed Example 34

60% Mixed Example 35

70% mixed comparative example 32

The test results are shown in Table 17.

Table 17

As is clear from Table 17, 20 compared with Comparative Example 20 which did not mix admixture, Comparative Example 21 which mixed non-classified goods of fly ash, and Comparative Example 22 and Comparative Example 24 which mixed 30 micrometer classified goods, In the case of Examples 27-29 which mixes a micrometer classification product, it turned out that the external appearance viscosity falls remarkably.

In addition, even in the case of mixing the 20 μm classified product, in Comparative Example 25 having a mixing ratio of less than 2%, there was almost no effect of reducing the external viscosity, and in the case of Comparative Example 26 exceeding 25%, it was followed by strength developability. It turned out to be falling.

On the other hand, in the case of using the blast furnace slag powder, in the case of Comparative Example 27 and Comparative Example 28 with a brain specific surface area of less than 5000 cm 2 / g, the external viscosity does not decrease, but the brain specific surface area is 5000 cm 2 / g or more and 10000 cm 2 / In the case of Examples 30-32 and Example 33 and Example 35 or less below, it turned out that an external appearance viscosity falls remarkably.

In addition, in the case where the blast furnace slag fine powder having a brain specific surface area of 5000 cm 2 / g or more and 10000 cm 2 / g or less is mixed, the mixing ratio of the blast furnace slag fine powder is less than 10% in the case of Comparative Examples 29 and 31 In the case of Comparative Example 30 and Comparative Example 32 exceeding 60%, there was little effect of reducing the viscosity, and it was found to be inferior in strength development.

In addition, when the brain specific surface area exceeds about 10000 cm 2 / g, the amount of high-performance AE water reducing agent, which is a powder for obtaining the same slump flow, tends to increase significantly.

Test Example 8

Using cement, thin aggregate, coarse aggregate, dispersant, and water, kneading is carried out using a mixer by forcing two-axis concrete with a water cement ratio of 20% and a unit quantity of 175 kg / m3, using a mixer, and compressive strength according to JIS A 1108. Was measured.

As cement in the material used, one obtained by grinding 1.0% of gypsum in terms of SO _{3 in} terms of SO ₃ was used for five types of clinkers (Examples 36 to 40) as shown in Table 18.

The powder degree of cement was 3100-3300 cm <2> / g in the brain specific surface area.

As the thin aggregate, one having a specific gravity of 2.59 was used as Yajucheon-san river sand.

In addition, as coarse aggregate, the thing with specific gravity 2.70 was used as high silicate crushed stone.

Furthermore, as the dispersant, Mighty 3000S (manufactured by Huawang Co., Ltd.), which is a high-performance AE water reducing agent, was used, and the amount of the additive was set to an amount such that the slump flow of concrete was 60 ± 5 cm.

Water used tap water.

In addition, a fly ash 20 µm classified product was used as the admixture corresponding to the cement composition.

The curing of the specimens for compressive strength test was performed by placing the specimens in a foamed Styropole container having a thickness of 10 cm and confirming the strength when subjected to the standard curing in water at 20 ° C. and the thermal history, and filling the foamed Styropol beads in the space. It was made into two types of adiabatic curing.

In the simple thermal curing, the temperature of the concrete was also measured using a thermocouple.

The test results are shown in Table 18.

Table 18

As is apparent from Fig. 18, more compressive strengths were obtained in each example.

However, when the content of 2CaO.SiO ₂ is less than 35% by weight, it is found that the content of 3CaO.SiO ₂ is relatively low, and the strength developability when thermal history is slightly decreased.

Further, if the 2CaO and SiO ₂ content exceeds 65% by weight, it was found that the strength-delayed.

Claims (9)

A cement clinker comprising Al ₂ O ₃ and Fe ₂ O ₃ in a cement clinker at 0.05 to 0.62 in an Al ₂ O ₃ / Fe ₂ O ₃ ratio. The cement clinker in the Al ₂ O ₃ and _{Fe 2 O 3, Al 2 O} 3 / Fe 2 O 3 ratio, the cement characterized in that it contains a cement clinker from 0.05 to 0.62. The cement according to Claim 2, wherein the content of 2CaO.SiO ₂ is 35 to 75% by weight. The cement according to claim 2 or 3, which is used for mass concrete. The cement according to claim 2 or 3, which is used for high strength and high flow concrete. The cement according to claim 5, wherein 2 to 25 wt% of fly ash having a particle diameter of 20 µm or less is blended. The cement according to claim 5, wherein the blast furnace slag fine powder having a brain specific surface area of 5000 to 10000 cm 2 / g is blended with 10 to 60% by weight. The high strength and high flow concrete which consists of the cement of any one of Claims 2-7, and a dispersing agent. 9. The high strength and high flow concrete according to claim 8, wherein the water cement ratio is 30% or less.