JP2002321950A - Filler cement composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a filler cement concrete having improved durability such as resistance to freezing and thawing and resistance to the permeability of salt. SOLUTION: The filler cement composition contains the fine powder of a blast furnace slag of 5.5-150 pts.wt., based on a filler cement of 100 pts.wt. The filler cement composition has one or more fillers selected from the group consisting of a fine limestone powder, a fine powder silicate, a crushed stone fine powder, and a fine slag powder having no active hydration.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a filler cement composition used for durable concrete.

[0002]

2. Description of the Related Art In recent years, from the viewpoint of protection of the global environment, it has been desired to reduce resources of carbon dioxide during cement production and to save resources by extending the life of concrete. Filler cement is a candidate cement, but concrete using filler cement has a problem in that freeze-thaw resistance is lower than concrete using ordinary Portland cement. Further, from the viewpoint of durability of concrete, not only freeze-thaw but also further improvement of durability such as salt permeation resistance is desired.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to improve the durability of concrete using a filler cement, such as freeze-thaw resistance and salt penetration resistance.

[0004]

Means for Solving the Problems The present inventors have conducted studies to solve the above problems, and as a result, 5.5 to 15 fine blast furnace slag powder was added to 100 parts by weight of filler cement.
Hardened cement, mortar or concrete using a filler cement composition containing 0 parts by weight was found to have improved durability such as freeze-thaw resistance and salt penetration resistance, and completed the present invention.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The filler cement used in the present invention is 100 parts by weight of Portland cement such as ordinary Portland cement, early-strength Portland cement, moderate heat Portland cement, low heat Portland cement, or sulfate-resistant Portland cement. Further, those containing 5.5 to 100 parts by weight of a filler are preferable.
Here, examples of the filler include one or more selected from the group consisting of limestone fine powder, silica stone fine powder, crushed stone fine powder, and slag fine powder having no hydration activity. These fillers have the effect of promoting the initial hydration of Portland cement between the ages of 1 day and 14 days. If the content of the filler is less than 5.5 parts by weight, the effect of promoting the hydration of the cement is small and the effect of improving the initial strength is not sufficient, and if the content of the filler exceeds 150 parts by weight, the long term The decrease in strength may be large.

[0006] The filler cement composition of the present invention contains 5.5 to 150 parts by weight of blast furnace slag fine powder based on 100 parts by weight of the filler cement. If the content of the blast furnace slag fine powder is less than 5.5 parts by weight, the effect of improving the durability is not sufficient, and if the content of the blast furnace slag fine powder exceeds 150 parts by weight, the decrease in the initial strength may be large. . Also,
The blast furnace slag fine powder preferably has a Blaine specific surface area of 3000 cm ² / g or more in order to promote hydration of the blast furnace slag.

[0007]

The present invention will be described below with reference to examples.

[0008] shows the materials used in the materials used in Table 1.

[0009]

[Table 1]

[0010]

[Table 2]

[0011]

[Table 3]

As a concrete comparative example, a filler cement obtained by mixing 40 parts by weight of limestone fine powder with 100 parts by weight of ordinary Portland cement was used. Further, as an example, a filler cement composition (comparative example) in which 15 parts by weight of a blast furnace slag fine powder was mixed with 100 parts by weight of the filler cement of the comparative example was used. Concrete was kneaded using the cement (composition) of the comparative example and the example according to the composition shown in Table 4. The mixing of the concrete was performed using a 50 L pan-type mixer, and the mixing amount was 30 L. The kneading is performed by kneading cement, fine aggregate and coarse aggregate for 15 seconds, and mixing water, AE agent and AE.
After adding the water reducing agent, the mixture was kneaded for 90 seconds. Further, since the concrete is designed with a compressive strength of 28 days of age, the water-cement ratio was adjusted so that the compounding strength of the concrete was the same as 36 N / mm ² at 28 days of age. The slump is 12
± 1.5 cm. The air volume was 4.5 ± 1.0%. In addition, the composition of Table 4 was determined by adjusting the s / a so as to satisfy the above conditions, and by performing a test so as to minimize the unit water amount.

[0013]

[Table 4]

Test method The freeze-thaw resistance of concrete is determined by JSCE-G5
01 The test was carried out in accordance with the “Method for testing freezing and thawing of concrete”. Table 5 shows the results of the freeze-thaw test and the change over time in the relative dynamic elastic modulus. The salt penetration resistance of the concrete was tested by a chloride penetration test. Specifically, after the concrete was prepared and cured in water until the age of 7 days,
After curing in the air at a temperature of 20 ° C. and a humidity of 60% for up to 8 days, four surfaces of the test piece (casting surface, bottom surface and two end portions) were sealed. The conditions for promoting salt penetration from the age of 28 days are 20 ° C.
After immersion in 3% NaCl aqueous solution for 3 days, temperature 20 ℃, humidity 6
One cycle of drying for 4 days in a 0% atmosphere. The chloride ion penetration depth was measured by spraying a 0.1% aqueous solution of sodium fluorescein and 0.01 N silver nitrate solution on the split surface of the specimen, and measuring the depth from the surface to the point where fluorescence was emitted with a vernier caliper. Table 6 shows changes over time in the salt penetration depth by the salt penetration test.

[0015]

[Table 5]

From Table 5 and FIG. 1, it can be seen that the concrete using the cement of the example has higher freeze-thaw resistance than the concrete using the cement of the comparative example.

[0017]

[Table 6]

From Table 6, it can be seen that the concrete using the cement of the example has a shallower salt penetration depth and a higher salt permeation resistance than the concrete using the cement of the comparative example.

[0019]

According to the filler cement composition of the present invention, it is possible to provide a filler cement concrete having improved durability such as freeze-thaw resistance and salt permeation resistance.

[Brief description of the drawings]

FIG. 1 is a diagram showing a change over time of a relative dynamic elastic modulus.

Continuation of the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) C04B 14:06) C04B 111: 24 111: 24 111: 76 111: 76 (72) Inventor Koichi Torii Minami Sakura, Chiba 2-4-2 Taiheiyo-shi, Taiheiyo Cement Co., Ltd. Central Research Institute (72) Inventor Makoto Kobayakawa 2-4-2 Daisaku, Sakura-shi, Chiba Pref. PB06 PB08 PC02 PC03 PC04 PC11 PC13

Claims (2)

[Claims] [Claim 1] For 100 parts by weight of filler cement,
A filler cement composition containing 5.5 to 150 parts by weight of blast furnace slag fine powder. 2. The method according to claim 1, wherein the filler is limestone fine powder, silica stone fine powder,
2. The filler cement composition according to claim 1, wherein the filler cement composition is at least one member selected from the group consisting of crushed stone fine powder and slag fine powder having no hydration activity.