JPH0687635A - Hydraulic cement - Google Patents

Abstract

PURPOSE:To increase the fluidity and fillability by mixing portland cement (OPC), an admixture coarse powder and an admixture fine powder in a specified ratio. CONSTITUTION:40-80 pts.wt. of a moderate-heat portland cement, 15-40 pts.wt. of an admixture coarse powder such as blast furnace slag powder having >=50mum 50%-average grain diameter and 3-35 pts.wt. of an admixture fine powder having <=5mum 50%-average grain diameter are mixed to produce a hydraulic cement. A water reducing agent (e.g. Pozzolis SP-9HS of the Nisso master builders Inc.) and a thickener (e.g. methyl cellulose) are added to the cement, as required, respectively in desired amt. to produce a hydraulic cement.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic cement that exhibits high fluidity when pouring concrete.

[0002]

2. Description of the Related Art For concrete, it is preferable that the fluidity is as great as possible during pouring because the working efficiency is good and the fluidity is increased simply by increasing the amount of kneading water during concrete kneading. Not only does this cause a problem in terms of properties, but it also causes an increase in breathing and corrosion of reinforcing bars due to a decrease in the solidity of concrete. On the other hand, in structural members such as walls and columns, vibration compaction by a vibrator cannot be sufficiently performed, which causes deterioration of concrete quality. Therefore, conventionally, as an effective means for improving the fluidity of concrete without increasing the amount of kneading water at the time of kneading concrete, a water reducing agent (high performance A
E water-reducing agent is used).

[0003]

However, if a water reducing agent (including a high-performance AE water reducing agent) is added in an excessively large amount in order to improve the fluidity, delay of setting and poor curing will occur, and the predetermined material However, there was a drawback that the target strength could not be obtained. Further, there is a drawback that the initial strength decreases as the added amount increases.

[0004]

DISCLOSURE OF THE INVENTION The present invention relates to a coarse powder and a fine powder of a mixed material having a specific particle size in Portland cement,
By adding an appropriate amount of each of a water reducing agent and a thickening agent as required, not only high fluidity that has not been obtained in the past can be obtained, but also the deterioration of the initial strength and the delay of setting which are the drawbacks of the prior art do not occur. They have found that they can provide highly fluid concrete, and have reached the present invention.

The Portland cement used in the present invention is
Ordinary Portland cement (hereinafter referred to as "OPC") or moderate heat Portland cement (hereinafter referred to as "MPC") is preferable, but MPC is preferable in order to obtain higher fluidity.

[0006] Examples of the coarse powder include coarse powder of Portland cement. In the method for producing the coarse powder, Portland cement clinker may be pulverized to a desired particle size. Return powder (hereinafter referred to as "return powder") may be used. Other coarse powders include blast furnace slag powder, fly ash (hereinafter referred to as "FA"), limestone powder, silica stone powder and stone powder. These coarse powders may be used alone or in combination of two or more kinds. The amount of coarse powder added is
15 to 40 to 80 parts by weight of Portland cement
40 parts by weight. It is preferably 20 to 35 parts by weight. If it is less than 15 parts by weight, high fluidity cannot be obtained, and if it exceeds 40 parts by weight, the strength is remarkably reduced. The fineness of coarse powder is 50
A% average particle diameter of 50 μm or more is preferable. The upper limit is, for example, within a range where the continuity of the particle size with the base cement is obtained.

As the above-mentioned fine powder, for example, fine powder of Portland cement can be mentioned. As a method for producing the fine powder, Portland cement clinker may be pulverized to a desired particle size, but if the particle size is suitable, As an easily obtainable product, dust collecting powder (hereinafter referred to as "buff powder") from a closed circuit mill when crushing cement can be diverted. Other fine powders include blast furnace slag fine powder, FA fine powder, calcium carbonate fine powder, silica fine powder and stone fine powder. As the calcium carbonate fine powder, crushed limestone (hereinafter referred to as "heavy calcium") or precipitated calcium carbonate for papermaking (hereinafter referred to as "light calcium") can be used. These fine powders may be used alone or in combination of two or more kinds.
The fineness of the fine powder is preferably 50% average particle diameter of 5 μm or less. The amount of the fine powder added is 3 to 35 parts by weight, preferably 10 to 80 parts by weight of Portland cement.
15 parts by weight. If it is less than 3 parts by weight, it hardly contributes to the strength development of the mortar or concrete, and if it exceeds 35 parts by weight, the fluidity is adversely affected.

[0008] A high-performance AE water reducing agent (hereinafter referred to as "SP") is added as necessary in order to suppress the fluidity and material separation during the mixing of mortar or concrete.
And thickeners. The SP may be one generally used for mortar or concrete, for example, Pozzolith SP- from Nisso Master Builders Co., Ltd.
9HS or NP-10, Kao Corporation's Mighty 200
0WH etc. are mentioned.

In the case of concrete, as the fluidity of the concrete improves, the material separation between the coarse aggregate and the mortar portion easily occurs. In that case, a thickener may be added as appropriate. As the thickener, for example, a commonly used one such as Methyl Cellulose manufactured by Shin-Etsu Chemical Co., Ltd .: trade name "Metroze" is used.

[0010]

【Example】

Examples 1-18 and Comparative Examples 1-9

The hydraulic cement of the present invention was applied to mortar, and flowability and strength tests were carried out. The chemical components and physical test results of OPC and MPC (both are commercial products) used in the examples are shown in Tables 1 and 2.

OPC return powder, blast furnace slag powder, FA, limestone powder, silica stone powder and stone powder were used as coarse powder.

OPC buff powder, blast furnace slag fine powder, FA fine powder, heavy calcium, light calcium, silica fine powder and stone fine powder were used as fine powder. Table 3 shows the chemical components of the coarse powder and the fine powder. In addition, those particle sizes are shown in Table 4. Heavy calcium and light calcium used as fine powder are dry crushed limestone products (P-10 manufactured by Toyo Fine Chemical Co., Ltd.) and precipitated calcium carbonate for paper manufacturing (Brilliant-1 manufactured by Shiraishi Industry Co., Ltd.).
5).

As the SP, Pozzolith SP-9HS manufactured by Nisso Master Builders was used. Sand for aggregate is Soma sand 3
No.4, No.5, No.6, No.7 are 25: 25: 25: 1
A mixture having a coarse grain ratio of 2.82 was used by mixing at a ratio of 2.5: 12.5.

Using the above materials, water / powder volume ratio =
Mortar was kneaded with a fixed composition of 1.00, sand / powder volume ratio = 1.91, and air content = 9%, and the fluidity and 28-day compressive strength of the mortar were examined.

The powder composition used, namely OPC, MPC,
Table 5 shows the mixing ratio of the coarse powder and the fine powder. In Table 6, the ratio of kneading water (abbreviation: W) and powder (abbreviation: P) used (hereinafter referred to as "W / P"), SP and methyl cellulose (hereinafter referred to as "MC") blending amount showed that. In addition, regarding mortar immediately after kneading in the same table, JASS 15M
The flow value according to -103 is shown. That is, JIS R52
The time required for the mortar to spread after the mortar was packed in a flow cone specified in No. 01, and the mortar began to spread after the cone was pulled up, that is, the "spread time" and the spread when the mortar was at rest, that is, "the flow value. "showed that. Further, the 28-day compressive strength of the material age is also shown in Table 6. In addition,
The absolute volume of each material per 1 mortar is P = 233
ml, W = 233 ml, sand = 444 ml, air volume = 9
%, SP = P × 2% and MS = 0.03 g. As a result, as shown in Comparative Example 1, although OPC alone had 2.0 parts by weight of SP added, it had almost no fluidity (flow value 126) and could not be put to practical use.

In Comparative Example 2, the OPC of Comparative Example 1 is replaced with MPC.
It has been replaced with. The flow value was improved up to 155, but the improvement effect was very small.

Examples 1 to 14 show the cases where coarse powder and fine powder were mixed with OPC or MPC. As a result, in all cases, the flow was 200 or more and the strength was sufficient. However, as shown in Comparative Example 3, when the amount of coarse powder (return powder) is extremely large, the flow is improved but the strength is reduced. On the other hand, as shown in Comparative Example 4, coarse powder (return powder)
If the amount is too small, it will not have a sufficient effect on the flow. Further, as shown in Comparative Example 5, if the amount of fine powder is too large, the viscosity becomes too high and the flowability deteriorates. As shown in Comparative Example 6, even if the amount of coarse powder is appropriate, If the amount is too small, it will not exhibit sufficient strength.

Next, Examples 15 to 18 show cases where the present invention was applied to concrete. The materials used in the examples are the same as those used in the mortar. However,
As the aggregate, crushed stone and land sand shown in Table 7 were used. In Table 8,
The composition of the powder when the coarse powder and the fine powder are appropriately combined with OPC or MPC is shown. Table 9 Concrete mix, J
It shows the spread of concrete (slump flow value) (hereinafter referred to as "SF") in the slump test of IS A1108 and the 28-day compressive strength of the material. Comparing the results with Comparative Example 7 which is a conventional technique, SF was large and good fluidity was exhibited.

Comparative Examples 8 and 9 show cases where the amounts of coarse powder (return powder) and fine powder (buff powder) outside the scope of the claims of the present invention were blended. In either case, the fluidity or strength was inferior to that of the present invention.

[0022]

The hydraulic cement of the present invention has the particle size composition of the entire powder suitable for the fluidity of mortar or concrete by adding coarse powder and fine powder in a specific particle size range and blending amount to Portland cement. We were able to. Further, by adding a water-reducing agent in an appropriate amount range and a thickening agent if necessary, it was possible to remarkably improve the fluidity without increasing the amount of kneading water and prevent the separation from the aggregate.
Therefore, it was possible to obtain a high-fluidity mortar or concrete which has high fluidity and material inseparability to the extent that compaction is not required at the time of driving, and has practically no problems in terms of setting and strength.

[0023]

When the hydraulic cement of the present invention is used,
A high-fluidity mortar or concrete can be easily obtained, and a high filling property can be obtained as compared with conventional mortar or concrete. Therefore, it is possible to completely fill concrete without vibrating and compacting into structural members such as tall walls and columns that have been a neck of construction without being able to apply a vibrator and the lower part of the opening. , Sufficient quality can be secured. In addition, since the high-fluidity concrete using the hydraulic cement of the present invention can significantly reduce the amount of concrete kneading water, it is possible to produce ultra-high strength concrete.

[0024]

[Table 1]

[0025]

[Table 2]

[0026]

[Table 3]

[0027]

[Table 4]

[0028]

[Table 5]

[0029]

[Table 6]

[0030]

[Table 7]

[0031]

[Table 8]

[0032]

[Table 9]

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Claims (1)

[Claims] 1. Portland cement 40 to 80 parts by weight, 50% 50 to 50% average particle diameter of mixed material coarse powder 15 to
A hydraulic cement comprising 40 parts by weight and 3 to 35 parts by weight of a mixed material fine powder having a 50% average particle diameter of 5 μm or less.