JP4428590B2 - Ultra-high strength cement admixture and cement composition - Google Patents

Description

【００２１】
実施例１
表２に示すベントナイトとギ酸類Ａの配合比を１：１とし、高性能ＡＥ減水剤の種類と配合量を変えて超早強セメント混和材を調製し、セメント１００重量部に対して超早強セメント混和材２重量部を配合したものをコンクリートに混合し、スランプと材齢２４時間、２８日の圧縮強度の測定を行った。その結果を表２に示す。尚、表１のコンクリート配合に減水剤を配合する場合は、同一スランプを得るのに少ない単位水量で済むため、単位水量を減らしてスランプを合わせた。
【００２２】
【表２】

【００２３】
本発明の超早強セメント混和材を使用することにより、水セメント比が低いコンクリートでも作業性は良好（スランプが大きい）で、コンクリートの超早強化や高強度化が可能であることが示されている。
【００２４】
実施例２
実施例１と同様に、表３に示す高性能ＡＥ減水剤ａとギ酸類Ａの配合比を約１：３とし、ベントナイトの配合量を変えて超早強セメント混和材を調製し、セメント１００重量部に対して超早強セメント混和材２重量部を配合してコンクリートに混合し、スランプと材齢２４時間、２８日の圧縮強度の測定を行った。その結果を表３に示す。尚、実施例１と同様に同一スランプを得るため、単位水量を調整した。
【００２５】
【表３】

【００２６】
本発明の超早強セメント混和材は、ベントナイトの配合量を変えても、コンクリートの作業性が良好で、超早強化や高強度化が可能であることが示されている。
【００２７】
実施例３
実施例１と同様に、表４に示す高性能減水剤ａとベントナイトの配合比を約１：３とし、ギ酸類の種類と配合量を変えて超早強セメント混和材を調製した。セメント１００重量部に対して超早強セメント混和材２重量部を配合してコンクリートに混合し、スランプと材齢２４時間、２８日の圧縮強度の測定を行った。その結果を表４に示す。
【００２８】
【表４】

【００２９】
本発明の超早強セメント混和材を使用することにより、コンクリートの作業性が良好で、超早強化や高強度化が可能であることが示されている。
【００３０】
実施例４
実験No.1-5の超早強セメント混和材について、セメント１００重量部に対して表５に示すように配合量を変えたこと以外は、実施例１と同様に行った。その結果を表５に示す。
【００３１】
【表５】

【００３２】
本発明の超早強セメント混和材を使用したコンクリートは、比較例のコンクリートと比べ、２４時間強度や２８日強度が著しく高いことが示されている。
【００３３】
【発明の効果】
本発明の超早強セメント混和材を使用することにより、水セメント比が低いコンクリートでも作業性が良好（スランプが大きい）で、コンクリートの超早強化や高強度化が可能となる。[0001]
BACKGROUND OF THE INVENTION
The present invention mainly relates to an ultra-high strength cement admixture and a cement composition used in the civil engineering and construction industries.
[0002]
[Prior art]
In recent years, the performance required for cement and concrete has been increasing more and more, and research on ultra-high-strength and high strength of cement and concrete has been actively conducted. Originally, the strength of cement and concrete largely depends on the water / cement ratio. For the purpose of minimizing the water / cement ratio as much as possible, as specified in JIS A 6204 “Chemical admixture for concrete”, a water reducing agent. And the use of high performance water reducing agents is generally prevalent. However, there is a limit in reducing the water / cement ratio, and there is a problem that workability must be sacrificed.
[0003]
On the other hand, many methods have been proposed for realizing ultra-fast strengthening and high strength by promoting cement hydration without reducing the water / cement ratio. For example, various methods for enhancing the strength of cement and concrete using accelerators such as calcium nitrate, calcium nitrite, calcium chloride, formic acid, sodium nitrate and calcium formate, and lactic acid and its salts have been proposed ( U.S. Pat.No. 3,427,175, JP 50-80315, JP 50-10998, JP 55-71653, U.S. Pat. 3801338, British Patent 1522501, and British Patent No. 1522502 etc.).
[0004]
[Problems to be solved by the invention]
In addition, high-performance AE water reducing agent is used in combination with concrete mixed with these accelerators to achieve ultra-fast strengthening and high strength. However, when a large amount of a high-performance AE water reducing agent is mixed, there is a limit because delay is increased, material separation of concrete is likely to occur, and the strength is adversely affected. Therefore, the present inventors have made various efforts to solve the above problems, and as a result, obtained the knowledge that the above problems can be solved by using a specific ultra-high strength cement admixture, and completed the present invention. It came to do.
[0005]
[Means for Solving the Problems]
That is, the present invention provides a high-performance AE water reducing agent, bentonite, and one or two or more types selected from the group consisting of formic acid, lactic acid and acetic acid in a total of 100 parts by weight. 2.5 to 35 parts by weight, 15 to 80 parts by weight of bentonite, 5 to 80 parts by weight of one or more selected from the group consisting of formic acid, lactic acid, acetic acid and salts thereof An early-strength cement admixture, which is a cement composition containing cement and the ultra-early-strength cement admixture.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in more detail.
[0007]
Although it does not specifically limit with the high performance AE water reducing agent of this invention, For example, the thing of a liquid type and a powder type of polycarboxylic acid type | system | group can be used, As the specific example, Grace Chemicals company make Examples include the product name “Darlex Super 200”, the product name “Leo Build SP-8HS” manufactured by NMB, and the product name “Tupol HP-11” manufactured by Takemoto Yushi Co., Ltd. In addition, various high-performance AE water reducing agents are commercially available, and any of them is used.
[0008]
The blending ratio of the high-performance AE water reducing agent is preferably 35 parts by weight or less, more preferably 2.5 to 20 parts by weight in terms of solid content in 100 parts by weight of the ultra-early strong cement admixture. If it exceeds 35 parts by weight, material separation may occur or sufficient early strength may not be obtained.
[0009]
The bentonite of the present invention is not particularly limited, but the Si / Al molar ratio is preferably 1.0 to 3.0, and more preferably 1.0 to 2.0. Outside this range, material separation of the concrete may occur easily. As the particle size of bentonite, a commercially available product can be used as it is, and even a coarse product having a particle size of about 200 to 350 mesh or less can be expected to have a sufficient effect.
[0010]
The blending ratio of bentonite is preferably 15 to 80 parts by weight and more preferably 25 to 60 parts by weight in 100 parts by weight of the ultra-fast early cement admixture. The appropriate blending amount varies depending on the concrete temperature, the blending amount of the water reducing agent, the unit cement amount in the concrete, etc., so it is difficult to uniformly define, but even if considering these fluctuation factors, The blending effect cannot be expected so much, and if it exceeds 80 parts by weight, the water reduction rate of the water reducing agent may be extremely reduced, which is not preferable. The higher the concrete temperature, the smaller the unit cement amount, and the smaller the amount of water reducing agent, the smaller the amount of bentonite.
[0011]
Formic acid, lactic acid, acetic acid and salts thereof (hereinafter referred to as formic acid) of the present invention are formic acid, lactic acid and acetic acid, and sodium, potassium, lithium, calcium, magnesium, barium and aluminum salts thereof. And salts such as salts, zinc salts and ammonium salts.
[0012]
The blending ratio of formic acids is preferably 5 to 80 parts by weight, more preferably 10 to 60 parts by weight, in 100 parts by weight of the ultra-early strong cement admixture. If it is less than 5 parts by weight, sufficient early strength may not be obtained, and if it exceeds 80 parts by weight, sufficient slump retention may not be obtained.
[0013]
The blending amount of the ultra-high-strength cement admixture of the present invention is not particularly limited, but usually 1 to 5 parts by weight in 100 parts by weight of the cement composition composed of cement and the ultra-high-strength cement admixture. Preferably, 2 to 3 parts by weight are more preferable. If it is less than 1 part by weight, the early strength and high strength, which are the effects of the present invention, may not be sufficiently obtained, and even if it exceeds 5 parts by weight, further enhancement of the effect cannot be expected.
[0014]
In the present invention, in addition to the high-performance AE water reducing agent, bentonite, and formic acids, a setting accelerator can be used in combination as necessary. Examples of the setting accelerator include alkali metal aluminates such as sodium aluminate, potassium aluminate, and lithium aluminate, alkalis such as sodium carbonate, potassium carbonate, lithium carbonate, sodium bicarbonate, potassium bicarbonate, and lithium bicarbonate. Metal carbonates and bicarbonates, sodium nitrate, potassium nitrate, lithium nitrate, calcium nitrate, sodium nitrite, potassium nitrite, lithium nitrite, calcium nitrite, and other nitrates and nitrites, sodium sulfate, potassium sulfate, lithium sulfate , Inorganic sulfates such as dihydrate gypsum, hemihydrate gypsum, anhydrous gypsum, aluminum sulfate, and amino alcohols such as calcium hydroxide, calcium oxide, alum, thiocyanate, thiosulfate and triethanolamine One or two of these It is possible to use a higher, it is to further promote super early strengthening and high strength.
[0015]
As the cement according to the present invention, ordinary, early strength, very early strength, low heat and moderate heat such as various portland cements, these cements were mixed with various cements mixed with blast furnace slag, fly ash and silica, limestone powder, etc. Examples thereof include filler cement and alumina cement.
[0016]
Further, in the present invention, in addition to the aggregate such as sand and gravel, the AE agent, the thickener, the rust preventive agent, the antifreeze agent and the polymer emulsion are added to the ultra-high strength cement admixture and the cement composition of the present invention, and One or more of cement expanding material, inorganic phosphate, boric acid and the like can be used in combination as long as the object of the present invention is not substantially impaired.
[0017]
Any existing stirring device can be used as the mixing device used when producing the ultra-high-strength cement admixture and cement composition of the present invention, such as a tilting barrel mixer, an omni mixer, a V-type mixer, and a Henschel. Mixers, nauter mixers, etc. can be used. Moreover, mixing may mix each material at the time of construction, and may mix part or all beforehand.
[0018]
【Example】
Hereinafter, the present invention will be described in detail by way of examples.
[0019]
The concrete mix used in the examples, the measurement method, and the materials used are shown.
<Concrete mix>
Based on the concrete composition shown in Table 1, concrete mixing is carried out by mixing 60 liters of concrete for 3 minutes with a forced mixing mixer (capacity 100 liters) in a room at 20 ° C. φ10 × 20 cm test piece) was measured.
<Measurement method>
Compressive strength: Measured according to JIS A 1108.
Slump test: Measured according to JIS A 1101.
<Materials used>
High-performance AE water reducing agent a: Commercially available polycarboxylic acid-based high-performance AE water-reducing agent b: Commercially available polycarboxylic acid-based high-performance AE water-reducing agent c: Commercially available polycarboxylic acid-based bentonite: Commercial product (swelling degree by the AC method 25)
Formic acid A: Reagent primary calcium formate B: Reagent primary formic acid C: Reagent primary sodium formate D: Reagent primary potassium formate E: Reagent primary lactate formic acid F: Reagent primary Calcium lactate formic acid G: Reagent primary sodium lactate formic acid H: Reagent primary potassium lactate formic acid I: Reagent primary calcium acetate formic acid J: Equal weight mixture of formic acid A and formic acid F Formic acid K: Formic acid A, Equal weight mixture of formic acid F and formic acid I Cement: Commercial early strength Portland cement Sand: Gravel from Himekawa, Niigata Pref. Water from Himekawa, Niigata Pref .: Tap water [0020]
[Table 1]

[0021]
Example 1
The mixing ratio of bentonite and formic acid A shown in Table 2 is 1: 1, and the type and amount of the high-performance AE water reducing agent is changed to prepare an ultra-high strength cement admixture. A mixture containing 2 parts by weight of a strong cement admixture was mixed with concrete, and the compressive strength of slump and material age of 24 hours and 28 days was measured. The results are shown in Table 2. In addition, when mix | blending a water reducing agent with the concrete mixing | blending of Table 1, since a small unit water amount is enough to obtain the same slump, the unit water amount was reduced and the slump was match | combined.
[0022]
[Table 2]

[0023]
By using the ultra-high strength cement admixture of the present invention, it is shown that workability is good (slump is large) even in concrete with a low water-cement ratio, and it is possible to strengthen concrete and increase its strength. ing.
[0024]
Example 2
In the same manner as in Example 1, the mixing ratio of the high-performance AE water reducing agent a and formic acid A shown in Table 3 was set to about 1: 3, and the amount of bentonite was changed to prepare an ultra-high strength cement admixture. 2 parts by weight of ultra-fast early cement admixture was blended with parts by weight and mixed with concrete, and the compression strength of slump and material age of 24 hours and 28 days was measured. The results are shown in Table 3. In addition, in order to obtain the same slump as in Example 1, the unit water amount was adjusted.
[0025]
[Table 3]

[0026]
It has been shown that the ultra-early strong cement admixture of the present invention has good workability of concrete even if the blending amount of bentonite is changed, and can be strengthened and strengthened very quickly.
[0027]
Example 3
In the same manner as in Example 1, the blend ratio of the high-performance water reducing agent a and bentonite shown in Table 4 was about 1: 3, and the kind and blending amount of formic acids were changed to prepare ultra-early strong cement admixtures. 2 parts by weight of an ultra-early strong cement admixture was blended with 100 parts by weight of cement and mixed with concrete, and the compressive strength of slump and material age of 24 hours and 28 days was measured. The results are shown in Table 4.
[0028]
[Table 4]

[0029]
It has been shown that by using the ultra-high strength cement admixture of the present invention, the workability of concrete is good and ultra-high strength and high strength can be achieved.
[0030]
Example 4
About the ultra-early strong cement admixture of Experiment No.1-5, it carried out like Example 1 except having changed the compounding quantity as shown in Table 5 with respect to 100 weight part of cement. The results are shown in Table 5.
[0031]
[Table 5]

[0032]
It has been shown that the concrete using the ultra-early strong cement admixture of the present invention has significantly higher 24 hour strength and 28 day strength than the comparative concrete.
[0033]
【The invention's effect】
By using the ultra-high-strength cement admixture of the present invention, even if the concrete has a low water-cement ratio, the workability is good (the slump is large), and the concrete can be strengthened very quickly and the strength can be increased.

Claims (2)

1. High-performance AE water reducing agent in solid content conversion in a total of 100 parts by weight of one or two or more kinds selected from the group consisting of high-performance AE water reducing agent, bentonite, formic acid, lactic acid, acetic acid and salts thereof . 5 to 35 parts by weight, 15 to 80 parts by weight of bentonite, one or two or more kinds selected from the group consisting of formic acid, lactic acid, acetic acid and their salts, 5 to 80 parts by weight Admixture.   A cement composition comprising cement and the ultra-early strong cement admixture according to claim 1.