JPH0578154A - High-strength glass fiber reinforced concrete composition - Google Patents

Abstract

PURPOSE:To provide a high-strength glass reinforced concrete composition having excellent strength, comprising glass fibers not to deteriorate for a long period of time. CONSTITUTION:In a glass reinforced concrete composition 100 pts.wt. Portland cement is blended with (1) 20-50 pts.wt. blast furnace slag, (2) 10-25 pts.wt. fly ash and/or fumed silica, (3) 5-20 pts.wt. anhydrous gypsum and/or gypsum dihydrate, (4) 0.5-3 pts.wt. high condensate of naphthalenesulfonic acid and formaldehyde and (5) 5-40 pts.wt. solid content of a dispersion of a polyacrylic ester-based polymer having 20-80 deg.C glass transition temperature to give a high- strength glass reinforced concrete composition.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to high strength glass fiber reinforced concrete compositions.

[0002]

2. Description of the Related Art Conventionally, glass fiber reinforced concrete (GRC) has been manufactured by a premix method or a direct spray method using cement materials, glass fibers, silica sand, water and the like as raw materials. In the production of the above-mentioned GRC, ordinary Portland cement, lime silicate / awin / slag ternary low-alkali cement, etc. are used as the cement material. Calcium deteriorates the glass fiber in the product, and the shrinkage due to drying becomes extremely large (shrinkage rate 10 to 1).
5 × 10 ⁻⁴ ).

On the other hand, as a method for solving the above problems, a method of adding a pozzolanic substance (fly ash, silica fume, etc.), a latent hydraulic substance (blast furnace slag powder, etc.), etc. in order to reduce the amount of calcium hydroxide produced. It has been known.

However, in order to reduce the amount of calcium hydroxide to the extent that glass fibers in GRC products are not adversely affected, for example, in the case of fly ash, 200 parts by weight or more per 100 parts by weight of cement and silica fume should be used. 40 parts by weight or more, 20 for blast furnace slag powder
It is necessary to add a large amount of 0 parts by weight or more. That is, the addition of such a large amount of each of the above substances significantly delays the strength development of cement, and it takes a long time before demolding is possible, resulting in a decrease in utility value as a practical concrete composition. I will let you.

On the other hand, when the above-mentioned three-component low-alkali cement proposed for solving the above-mentioned problems caused by ordinary Portland cement is used, deterioration of glass fiber can be avoided, but the product itself is expensive. In addition to S
Since there is a large amount of O ₃ and it is necessary to perform steam curing, there is a serious problem of causing rusting of the steel form and embedded metal fittings.

Furthermore, the GRC products obtained by using these cement materials have the drawback that their bending proportional limit strength is relatively low (about 100 kgf / cm ² ), and therefore these drawbacks are eliminated. There is a demand for the development of new concrete compositions that can be used.

[0007]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a high strength glass fiber reinforced concrete composition which has excellent strength and does not deteriorate the glass fiber for a long period of time.

As a result of intensive studies conducted by the present inventors in view of the above-mentioned problems of the prior art, a cement composition having a specific composition containing a polyacrylate polymer dispersion having a certain glass transition temperature was found to be It has been found that the above problems can be solved, in particular, it is possible to prevent deterioration of the glass fiber by effectively reducing the amount of calcium hydroxide, which is a harmful substance generated in GRC, and to develop an excellent bending proportional limit strength. The invention was completed.

That is, the present invention provides (1) 20 to 50 parts by weight of blast furnace slag powder with respect to 100 parts by weight of Portland cement in a glass fiber reinforced concrete composition,
(2) Fly ash and / or silica fume 10-
25 parts by weight, (3) anhydrous gypsum and / or gypsum dihydrate 5-2
0 parts by weight (4) 0.5 to 3 parts by weight of a high condensation product of naphthalenesulfonic acid formaldehyde and / or a high condensation product of melaminesulfonic acid formaldehyde, and (5) a polyacrylic acid ester-based polymer dispersion having a glass transition temperature of 20 to 80 ° C. The present invention relates to a high-strength glass fiber reinforced concrete composition characterized by being added with John solids content of 5 to 40 parts by weight.

The concrete composition of the present invention will be described in detail below.

As the Portland cement used in the present invention, known ones can be used, and examples thereof include various Portland cements such as ordinary Portland cement, early strength Portland cement, moderate heat Portland cement and sulfate resistant Portland cement. These Portland cements may be used alone or in combination of two or more.

As the blast furnace slag powder (component (1)),
There is no particular limitation as long as it has latent hydraulic properties. However, when the Blaine surface area is less than 3000 cm ² / g, the activity may decrease and the performance of GRC may be deteriorated. Therefore, it is preferable to use Blaine surface area of 3000 cm ² / g or more. The compounding amount is 20 to 50 parts by weight with respect to 100 parts by weight of Portland cement.
If the blending amount is less than 20 parts by weight, calcium hydroxide produced from cement cannot be reduced,
Causes delayed setting and reduced strength. On the other hand, if it exceeds 50 parts by weight, strength development will be delayed and it will take a long time to demold, which is not preferable. The blast furnace slag powder in the cement composition of the present invention plays a role of reducing calcium hydroxide produced from cement by a hydration reaction due to its latent hydraulic property.

As the fly ash and / or silica fume (component (2)), any of those generally used can be used. In order to increase the reaction activity of the pozzolanic reaction, fly ash has a brain surface area of 3000c.
m ² / g or more, 100,000 in silica fume
cm ² / g or more, more preferably 200000cm ² /
It is better to be more than g. The compounding amount is 10 to 25 parts by weight based on 100 parts by weight of Portland cement. If the content is less than 10 parts by weight, the calcium hydroxide produced from the cement cannot be reduced, and if it exceeds 25 parts by weight, strength development becomes slow and it takes a long time to demold. Not preferable. The fly ash and / or silica fume in the cement composition of the present invention plays a role of reducing calcium hydroxide produced from cement by the pozzolanic reaction, similarly to the blast furnace slag powder. On the other hand, other pozzolanic substances include silicic acid clay, volcanic ash, diatomaceous earth, calcined clay, calcined shale, etc.
It cannot be used because it does not meet the purpose of the present invention of short-term strength development.

As anhydrous gypsum and / or gypsum dihydrate (component (3)), those obtained by a conventional method can be used. These are usually those having a Blaine surface area of 2000 cm ² / g or more, preferably 3000 cm ² / g or more. The compounding amount is 5 to 20 parts by weight with respect to 100 parts by weight of Portland cement. If the blending amount is less than 5 parts by weight, the produced calcium hydroxide cannot be reduced and the final product has a large drying shrinkage, which is not preferable. Also, if it exceeds 20 parts by weight, expansion cracks and GRC due to abnormal occurrence of ethrin guide due to curing conditions may occur.
The product may warp. Thus, the anhydrous gypsum and / or gypsum dihydrate in the cement composition of the present invention reacts with the alumina component, calcium component, silica component, etc. supplied from the Portland cement or blast furnace slag powder to form an ethrin guide. By doing so, it has the function of reducing the amount of calcium hydroxide and further suppressing the drying shrinkage of the final product. Hemihydrate gypsum cannot be used because it induces pseudo-setting of cement and reduces workability.

As the naphthalene sulfonic acid formaldehyde high condensation product and / or the melamine sulfonic acid formaldehyde high condensation product (component (4)), known ones can be used. Compounding amount is Portland cement 100
0.5 to 3 parts by weight relative to parts by weight. If the content is less than 0.5 part by weight, the water reducing effect will not be sufficiently exhibited. On the other hand, if it exceeds 3 parts by weight, the viscosity of the kneaded product becomes excessively high, the curing is delayed, and the strength of the GRC product is lowered, which is not preferable. These high-condensates play a role as so-called high-performance water reducing agents in the cement composition of the present invention, and can suppress the amount of water to be added to the cement composition to a small amount when preparing a kneaded product.

As the polyacrylic acid ester-based polymer dispersion (component (5)), known ones can be used, for example, those obtained by copolymerizing acrylic acid can be used. It is essential to use one having a glass transition temperature of 20 to 80 ° C, preferably 40 to 60 ° C. If the temperature is less than 20 ° C, the effect of improving the bending proportional limit strength cannot be sufficiently achieved, and if it exceeds 80 ° C, a polymer film cannot be formed by normal temperature curing.
The compounding amount is 5 to 40 parts by weight in terms of solid content with respect to 100 parts by weight of Portland cement. If the blending amount is less than 5 parts by weight, the bending proportional limit strength cannot be improved and the glass fiber is deteriorated. On the other hand, if it exceeds 40 parts by weight, the viscosity of the kneaded product becomes excessively high, the curing is delayed, and the strength of the GRC product is lowered, which is not preferable. The polyacrylic acid ester-based polymer dispersion in the cement composition of the present invention forms a co-matrix structure of the cement gel and the polymer while increasing the binding force of the polymer existing between the cement gel or the cement gel-aggregate, It enhances the bending proportional limit strength of GRC products and exerts the effect of suppressing deterioration of glass fibers and drying shrinkage of products due to calcium hydroxide.

Each of the above composition components (components (1) to (5))
According to known manufacturing methods such as premix method and direct spray method using known glass fibers, aggregates, water, etc. as raw materials,
The high-strength glass fiber reinforced concrete composition of the present invention is obtained. In the production of the composition, if necessary, various known additives such as an expanding material, a shrinkage reducing agent, a water retention agent, and a retarding agent may be used. For example, the expanding material may be a calcium sulfaluminate-based material, Examples include quick lime compounds, and examples of shrinkage reducing agents include lower alcohol alkylene oxides, and examples of retarders include citric acid.

[0018]

According to the high strength glass fiber reinforced concrete composition of the present invention, the following excellent effects can be obtained. (1) GRC with a small amount of pozzolanic substance and latent hydraulic substance
Since the calcium hydroxide content in the product can be suppressed to 1% by weight or less, deterioration of the glass fiber in the GRC product can be effectively prevented without delaying the development of cement strength. (2) The formation of calcium hydroxide is remarkably suppressed, and the surface of the glass fiber is covered with a polymer, so that the deterioration of the glass fiber in GRC can be prevented and GR
The durability of the C product itself can be improved. (3) Pozzolanic activity and latent hydraulic property can be exhibited with a small amount of water used such that the water / cement ratio is 50% or less. (4) Glass transition temperature 20 to 80 ° C. Since the addition of a polyacrylic acid ester-based polymer dispersion enhances the bonding force between cement gels or between cement gels and aggregates, a co-matrix structure of cement gels and polymers is formed. Can exhibit excellent bending proportional limit strength. (5) The drying shrinkage of GRC is relatively small. (6) Since steam curing is not required in manufacturing, excellent productivity and workability are exhibited. (7) Steel formwork used in the manufacture of GRC products,
Alternatively, it is possible to prevent rusting of embedded metal fittings in the product.

[0019]

EXAMPLES The present invention will be described in more detail with reference to Examples and Comparative Examples.

Examples 1 to 7 High-strength glass fiber reinforced concrete compositions (Sample Nos. 1 to 7) having the compositions shown in Table 1 below were prepared by the direct spray method.

The blast furnace slag powder used has a brane surface area of about 3000 cm ² / g, and fly ash has a surface area of about 3 as well.
000 cm ² / g, silica fume is about 200,000 c
m ² / g, anhydrous gypsum was about 3000 cm ² / g.

The polyacrylic ester polymer dispersion shown in the table is "2F-914" (Kanebo NSC) having a solid content of 45% by weight and a glass transition temperature of 60 ° C.
“Mighty 150RX” (manufactured by Kao Corporation) as a high-condensation product of naphthalenesulfonic acid formaldehyde.
Manufactured) was used. In addition, a calcium sulfaluminate-based expander (“Denka CSA”, manufactured by Denki Kagaku Kogyo Co., Ltd.) is used as an expander, and a lower alcohol alkylene oxide adduct-based shrink reducer (“Tetraguard AS” is used as a shrinkage reducer.
20 ", manufactured by Sanyo Kasei Co., Ltd., and citric acid was used as a retarder.

[0023]

[Table 1] Comparative Examples 1 to 9 In the same manner as in Example 1, concrete compositions (Sample Nos. 8 to 16) having the compositions shown in Table 1 were prepared.

In addition, in Sample No. 14, "Mighty 150" was obtained as a high-condensation product of naphthalenesulfonic acid formaldehyde.
(Manufactured by Kao Corporation) was used as a polyacrylic acid ester-based polymer dispersion in Sample No. 16 and had a solid content of 45.
% By weight, glass transition temperature 0 ° C. “Polytron A-122
1 "(manufactured by Asahi Kasei Corp.) was used instead of that of Example 1.

[0025]

[Test Example] A test was conducted on each sample obtained in the examples and comparative examples.

Test Example 1 Sample Nos. 1 to 4 obtained in Examples 1 to 4 and Comparative Examples 1 to 1
For the sample Nos. 8 to 13 obtained in No. 6, the pot life,
The curing time, flexural strength and calcium hydroxide production were investigated. The test results are shown in Table 2.

The above test was determined by the following measuring methods. a) Pot life: The time until a flow value of 130 mm or more was secured against the initial value of 150 mm was measured by a flow value test according to JASS 15M-103. b) Curing time ... The setting time in the setting test of the physical test method for cement according to JIS R5201 was measured. The evaluation reference value is within 10 hours. c) Bending strength: Measured by a physical test method for cement according to JIS R5201. Bending strength is 3 as the evaluation standard value.
0kgf / cm ² or more, compressive strength 150kgf / cm
It is ² or more. d) Calcium hydroxide production ... Measured by differential thermal analysis. The evaluation standard value is 1% or less after 1 month and 0% after 3 months.

[0028]

[Table 2] From these results, it can be seen that with the GRC according to the present invention, an appropriate pot life of the kneaded product can be obtained and the curing time can be shortened. Also, the initial strength can be increased while reducing the calcium hydroxide content.

Test Example 2 Sample Nos. 5 to 7 obtained in Examples 5 to 7 and Comparative Examples 7 to
The deterioration state, bending strength, drying shrinkage and rusting property of the glass fibers of Sample Nos. 14 to 16 obtained in No. 9 were examined. The test results are shown in Table 3. In addition, Table 3 also shows the results of the examination of the necessity of steam curing and the rusting property of the metal of the steel form.

The above test was determined by the following measuring methods. e) Degradation status of glass fiber: After curing in air at 20 ° C. for 28 days, accelerated curing in hot water at 60 ° C. for 56 days was observed with a scanning electron microscope to determine the presence or absence of deterioration. f) Bending strength: After curing in air at 20 ° C. for 28 days, bending proportional limit strength was measured by a center loading method with a span of 200 mm and a loading speed of 2 mm / min. Specimen size is 250m
It was set to m × 50 mm × 10 mm. g) Dry shrinkage: Measured according to JIS A1129.
That is, the specimen is placed and the relative humidity is 85 at a temperature of 20 ° C.
% And cured for 24 hours and demolded. Next, at a temperature of 20 ° C., a base length was taken by a comparator method in an atmosphere with a relative humidity of 60%, and the length was measured at each age. h) Rusting property ... Visual observation was performed.

[0031]

[Table 3] In addition, the sample (No 5) obtained in Example 5 and Comparative Example 7
Scanning electron micrographs (× 2000) of the sample (No. 14) obtained in Example 1 are shown in FIGS. 1 and 2, respectively. As a result, fiber breakage was recognized in the glass fiber in GRC of the comparative example (FIG. 2).

From the results shown in Table 3, a conventional product using lime silicate / ayne / slag type low alkaline cement (Sample N
No. 15) required steam curing, and rusting of metal such as steel form was observed. In addition, both the sample No. 15 and the sample No. 14 made of ordinary Portland cement had a low bending proportional limit strength of about 100 kgf / cm ² . Furthermore, even in sample No. 16 using a polyacrylate polymer dispersion having a glass transition temperature of 0 ° C., 1
The bending proportional limit strength was as low as about 00 kgf / cm ² . On the other hand, the GRC according to the present invention can omit the steam curing step in the production thereof, can sufficiently suppress the rusting of the metal, can prevent the deterioration of the glass fiber in the GRC, and have a high bending proportional limit strength and a dry shrinkage. It can be seen that it is small and has excellent performance.

From the above, it is clear that the high-strength glass fiber reinforced concrete composition of the present invention exhibits excellent effects.

[Brief description of drawings]

FIG. 1 is a photograph instead of a drawing showing the shape of glass fibers in GRC of the present invention (Sample No. 5).

FIG. 2 is a photograph instead of a drawing, which shows the shape of glass fibers in GRC of Comparative Example 7 (Sample No. 14).

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location C04B 24/22 E 2102-4G 24/30 D 2102-4G 28/04 8618-4G (72) Invention Person Mikio Wakasugi 1-6-23 Hanazono Kita, Nishinari-ku, Osaka-shi, Osaka Prefecture 1105, Prince Sato Garden Hanazono

Claims (1)

[Claims] 1. A glass fiber reinforced concrete composition comprising (1) with respect to 100 parts by weight of Portland cement.
20 to 50 parts by weight of blast furnace slag powder, (2) 10 to 25 parts by weight of fly ash and / or silica fume, (3)
5-20 parts by weight of anhydrous gypsum and / or gypsum dihydrate (4) High-condensation product of naphthalenesulfonic acid-formaldehyde and / or high-condensation product of melaminesulfonic acid-formaldehyde 0.5-
A high-strength glass fiber reinforced concrete composition comprising 3 parts by weight and (5) 5 to 40 parts by weight of a solid content of a polyacrylic acid ester-based polymer dispersion having a glass transition temperature of 20 to 80 ° C.