JPH11209152A - Cement admixture and cement composition containing it - Google Patents

Abstract

(57) [Summary] [Problem] (1) Lot number of cement used Regardless of the brand or brand, it greatly improves the water reduction rate of conventional high-performance water reducing agents. (2) High strength is easily obtained. To provide a cement admixture that solves the problems of (1) and (2) and a cement composition containing the same. SOLUTION: It contains a high-performance water reducing agent, one or more of sodium or potassium carbonate, sodium or potassium bicarbonate, tripolyphosphate, and ammonium bicarbonate, and lignin sulfonate. And a cement admixture characterized by the above.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cement admixture for mortar and concrete used in civil engineering and building structures and secondary concrete products, and a cement composition containing the same. More specifically, the present invention relates to a cement admixture for greatly increasing the water reduction rate and easily obtaining high strength, and a cement composition containing the same.

[0002]

2. Description of the Related Art High performance water reducing agents such as polyalkylallyl sulfonate type, melamine formalin resin sulfonate type and aromatic amino sulfonate type polymer are polyol type water reducing agent and oxycarboxylic acid. Compared with general water reducing agents such as salt water reducing agents, the water reduction rate is large, and even if added in a relatively large amount, it does not cause abnormal setting or excessive delay of cement,
Since it has low air entrainment, it is easy to obtain high strength for civil engineering structures, and it is suitable for manufacturing high-strength concrete products. Further, in order to increase the strength, it is a common means to use a high-performance water reducing agent and a high-strength admixture containing gypsum, activated silica, and a pozzolan substance in combination.

[0003] However, a high performance water reducing agent is cement 1
The water reduction rate reaches a peak at about 2 parts by weight in terms of solid content with respect to 00 parts by weight. In addition, since the strength when a high-performance water reducing agent is added is ultimately determined by the water cement ratio, if the water reduction rate can be further increased, not only can a higher strength be easily obtained, but also the strength should be constant. Then, the unit cement amount and the unit high strength admixture amount can be reduced,
Economical production of concrete becomes possible.

[0004] In the combined use of a high-performance water reducing agent and a carbonate of an alkali metal, the inventor of the present invention added citric acid, tartaric acid, malic acid or a salt thereof and an alkali metal carbonate to concrete containing the high-performance water reducing agent. A method for improving the workability of concrete for preventing slump loss by adding bicarbonate was proposed (Japanese Patent Publication No. 1-52342).

However, in a combined system of citric acid or the like and an alkali metal carbonate or the like, the alkali metal carbonate or the like has an excellent effect in promoting slump loss prevention, but has no effect of increasing the water reduction rate. I can't.

Further, the present inventors have proposed a cement admixture in which a high-performance water reducing agent, bentonite and the like and an alkali metal carbonate are used in combination, and improve the abnormal viscosity of concrete to which the high-performance water reducing agent is added to retain water. We have also proposed an admixture which is good in plasticity and does not cause sagging of plastics, and which also improves ironing finish (Japanese Patent Application Laid-Open No. Sho 64-3040). However, even in this case, the alkali metal carbonate and the like show a great effect in improving the plasticity of concrete using bentonite,
No effect of increasing the water reducing rate was observed, indicating that the effect of increasing the water reducing rate of the high-performance water reducing agent is often lost when alkali metal carbonates and the like are used in combination with other components.

The present inventors have conducted intensive studies with the aim of increasing the water reduction rate of the high-performance water reducing agent. As a result, the water reduction rate can be reduced by using an appropriate amount of an alkali metal carbonate or a tripolyphosphate together with the high-performance water reducing agent. Admitted to improve.

However, in this method, the cement lot No. It was found that if the (manufacturing date) or brand changed, some of the water reduction rates did not improve at all.

Therefore, as a result of intensive studies to solve the above-mentioned problems, the present inventors have found that the above can be achieved by further adding a specific component conventionally known as a general water reducing agent, and have completed the present invention.

[0010]

That is, the present invention provides (1) a high-performance water reducing agent and one or more of sodium or potassium carbonate, sodium or potassium hydrogen carbonate, tripolyphosphate, and ammonium hydrogen carbonate; A cement admixture characterized by containing two or more kinds and a lignin sulfonate; and (2) one or more kinds of gypsums, activated silica, and pozzolan substances (1) ), A cement composition containing (3) cement and the cement admixture according to (1) or (2), and (4) 100 parts by weight of cement, a high-performance water reducing agent is solidified. 0.3 to 2.5 parts by weight in terms of minutes and one or two of sodium or potassium carbonate, sodium or potassium bicarbonate, tripolyphosphate, and ammonium bicarbonate More than 0.05 to 0.6
Parts by weight and lignin sulfonate in an amount of 0.0
(5) Further, one or more of gypsums, activated silica, and pozzolanic substances are each converted to CaSO ₄ in an amount of 1 to 5 parts by weight.
(4) The cement composition as described in (4), which contains -15 parts by weight, 1-12 parts by weight, and 2-15 parts by weight.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.
The high-performance water reducing agent used in the present invention is a polyalkylallyl sulfonate-based, aromatic aminosulfonate-based high-performance water reducing agent, and a melamine formalin resin sulfonic acid salt-based as a main component. One or more of them may be used in combination. More preferred are polyalkylallyl sulfonate-based and aromatic amino sulfonate-based high-performance water reducing agents.

Examples of commercially available high-performance water reducing agents include, for example, polyalkylallylsulfonic acid salts such as methylnaphthalenesulfonic acid formalin condensate, naphthalenesulfonic acid formalin condensate, and anthracenesulfonic acid formalin condensate. Salts, and commercially available products are "FT-500" manufactured by Denki Kagaku Kogyo Co., Ltd .; "Mighty 100" manufactured by Kao Corporation;
0 "," Mighty 2000 "series, etc., Daiichi Kogyo Seiyaku Co., Ltd. product name" Celflow 110P ", Takemoto Yushi Co., Ltd. product name" Pole Fine 510N ", etc., Sanyo Kokusaku Pulp Co., Ltd. product name" Sunflow PS ", "Sunflow HS70
"0" and the like are typical. Further, as the aromatic aminosulfonates, “Palic 2” manufactured by Fujisawa Pharmaceutical Co., Ltd.
00 ”series. Examples of the melamine formalin resin sulfonate-based high-performance water reducing agent include Denka Grace's trade name "FT-3S" and Showa Denko's trade names "Molmaster 10" and "Molmaster 20" (hereinafter, referred to as "Molmaster 20"). These are simply called high-performance water reducers). Among these, "Mighty 100", "Cell Flow 110P", "Mole Master 10", and "Mole Master 20" are commercially available in powder form, and others are commercially available in liquid form. The solid content of the sulfonate-based high-performance water reducing agent is about 40% by weight.

The sodium or potassium carbonate, sodium or potassium bicarbonate, ammonium bicarbonate and the like used in the present invention are used as a setting and hardening accelerator for cement or as a quick setting agent depending on the amount of cement. . Also, sodium and potassium tripolyphosphates are known as cement setting retarders (hereinafter collectively referred to simply as carbonates and the like).

These carbonates and the like have a remarkable action of improving the water reduction rate by being added in combination with a high-performance water reducing agent in a range that does not cause rapid setting or hardening failure. As described above, the water reduction rate may not be improved at all depending on the (production date) and the brand. In addition, lithium carbonate, hydrogencarbonate, and ammonium carbonate, which are the same alkali metals as sodium and potassium, have a small effect of improving the water reduction rate.

The combined use of the high-performance water-reducing agent of the present invention and a carbonate, etc. makes it possible to increase the water-reduction rate irrespective of the lot number and brand of cement by adding an appropriate amount of ligninsulfonate. The cause is not clear.

The lignin sulfonate used in the present invention is used as a component of a general water reducing agent along with a polyol water reducing agent, an oxycarboxylic acid water reducing agent and the like. In addition, in general water reducing agents such as polyol-based water reducing agents, oxycarboxylate-based water reducing agents, and high-performance AE water-reducing agents such as polycarboxylate-based water reducing agents, water is reduced even when used in combination with the high-performance water reducing agent of the present invention and carbonates. The effect cannot be used in the present invention because the effect is so small that it cannot be used industrially or the water reduction rate may be reduced. Also, when a high-performance water reducing agent and a lignin sulfonate are used in combination without adding a carbonate or the like, the effect of improving the water reducing rate is extremely small.

Lignin sulfonate is generally commercially available in powder or liquid form. For example, Borregaa
RD Sarpsborg brand name "Ultrazine" etc., Denka Grace brand name "Darlex WRDA", "Darlex dalatard" etc., Pozoris Bussan product name "No. 8"
, “No. 8IMP”, “No. 10L”, and the like, and “Sunflow S”, “Sunflow R” manufactured by Sanyo Kokusaku Pulp and the like. Among these, "Ultrazine", "No. 10L", "Sunflow S", and "Sunflow R" are commercially available as powders, and others are commercially available as liquids and have a solid content of 20% by weight. %.

The mixing ratio of the high-performance water reducing agent to the carbonate and the like and the ligninsulfonate is 0.3 to 2.5 parts by weight of the high-performance water reducing agent in terms of solids per 100 parts by weight of cement. It is preferable to mix the salt and the like in a range of 0.05 to 0.6 parts by weight, and the lignin sulfonate in a range of 0.05 to 0.5 part by weight in terms of solid content. If the amount of carbonate or lignin sulfonate is in an appropriate amount, the water reducing rate increases as the amount of the high-performance water reducing agent increases, but if the amount of the high-performance water reducing agent is less than 0.3 parts by weight per 100 parts by weight of cement, it is added. The effect is small, and the water reduction rate reaches a peak even when the content exceeds 2.5 parts by weight.

On the other hand, if the mixing ratio of carbonate or the like is less than 0.05 part by weight with respect to 100 parts by weight of cement, even if the mixing amount of a high-performance water reducing agent or lignin sulfonate is appropriate, the effect of improving the water reducing ratio is small. Addition of more than 6 parts by weight is not preferable because the water reduction rate may decrease, or rapid setting may occur, or excessive delay may occur.

When the compounding ratio of lignin sulfonate is less than 0.05 part by weight with respect to 100 parts by weight of cement, even if the compounding amount of a high-performance water reducing agent or carbonate is appropriate, the effect of improving the water reducing rate is small, and It is not preferable to add more than 1 part, since the setting may be significantly delayed.

The gypsum of the present invention is gypsum dihydrate, gypsum hemihydrate,
Refers to type III anhydrous gypsum, type II anhydrous gypsum, etc., which has the effect of promoting water reduction and improving strength. When the strength is kept constant, the amount of gypsum or the like can be reduced.

When gypsum is used alone or in combination with one or more active silica or pozzolanic substances, the strength is increased in the range of 1 to 15 parts by weight per 100 parts by weight of cement. But in standard curing 2 to 7 parts by weight,
In steam curing, 3 to 10 parts by weight is preferable. If it is less than each of the ranges, the effect of increasing the strength is small, and if it is added beyond the respective ranges, the elongation of the strength is stagnated, which is not preferable.

The activated silica used in the present invention refers to silica fume, calcined wood ash, ultrafine siliceous materials such as metakaolin and aerosil. Silica fume is amorphous SiO ₂ of ultrafine generated when producing a metal silicon and silicon alloy in an electric furnace, remains after firing reed, silicified trees bamboo and firing ash silicified wood an ash, metakaolin kaolinite, dickite, amorphous aluminosilicate compound calcined kaolin minerals such as halloysite, Aerosil are amorphous SiO ₂ of artificially synthesized ultrafine powder.

The active silica may be used alone or in combination with one or more gypsums or pozzolanic substances.
The expression intensity is increased in the range of parts by weight,
10 to 10 parts by weight, more preferably 3 to 8 parts by weight. If it is less than 1 part by weight, the effect of increasing the strength is small,
Addition of more than 12 parts by weight is not preferable because the elongation of the strength becomes slow.

The pozzolanic substance used in the present invention includes acid clay, activated clay, pyrophyllite, zeolite,
Aluminosilicate clay minerals such as kaolin minerals (except for bentonite), their calcined products (excluding metakaolin, including calcined bentonite), fly ash,
It indicates blast furnace slag powder (latent hydraulic substance), diatomaceous earth, etc., and becomes active when used in combination with carbonates and the like, so that higher strength can be obtained.

The mixing ratio of the pozzolanic substance is not limited to whether the pozzolanic substance is used alone or in combination with one or more of gypsum and activated silica.
2 to 15 parts by weight with respect to parts by weight, preferably 3 to
10 parts by weight. If it is less than 2 parts by weight, the effect of addition is small, and if it exceeds 15 parts by weight, no further increase in strength is observed, which is not economically preferable.

The strength obtained when gypsum, activated silica, and pozzolanic substances are added alone is different from the strength obtained when
When these are arbitrarily used, a synergistically higher strength can be obtained.

The cement used in the present invention includes various portland cements such as ordinary, fast, super fast, moderate heat, white, and low heat (belite cement), as well as blast furnace slag, fly ash, and silica powder. And slag-based cement in which slag is blended to a JIS standard value or more, and the like.

The cement admixture of the present invention is added to a mixer together with other concrete materials when kneading mortar or concrete, and the kneading method may be a commonly used method. The method of addition is not particularly limited.

Therefore, each component, whether solid or liquid, may be added separately when kneading the mortar or concrete. When a powdery high-performance water reducing agent is used, the other components may be added in powder form in advance. You may mix with a component and add it all at once. Alternatively, carbonates or the like may be dissolved in a liquid high-performance water reducing agent and added separately from other solid components, or the entire admixture may be mixed and suspended with part or all of the water. It may be turbid and added as a slurry.

[0031]

EXAMPLES The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. Hereinafter, various materials used in the examples are collectively shown.

<Materials Used> Cement: ordinary Portland cement manufactured by Company A and Company B River sand: natural sand from Himekawa, Niigata Water: tap water “High-performance water reducing agent” naphthalenesulfonic acid formalin condensate (trade name, manufactured by Kao Corporation) "Mighty 100", powdered "carbonate, etc." a. Sodium hydrogen carbonate: first-class reagent b. Sodium carbonate: Same as above c. Potassium hydrogen carbonate: Same as above d. Potassium carbonate: Same as above e. Ammonium hydrogen carbonate: Same as above f. Tripolyline Sodium acid: Same as above "Lignin sulfonate" Lignin sulfonate Na: Borregaard Sarpsborg product name "Ultrazine" Powdered lignin sulfonic acid Mg: Denka Grace product name "Darlex WRDA", liquid, solid content 18% lignin sulfone Acid Ca: Industrial product, powdered “gypsum” A. Type II anhydrous gypsum: hydrofluoric acid generated by-product gypsum, Blaine specific surface area 000cm ² / g b gypsum:. Industrial, Blaine specific surface area of 6500 cm ² / g c hemihydrate gypsum:.. A heat treatment at 140 ° C. The filtrate, Blaine specific surface area of 10000 cm ² / g or more two type III anhydrous gypsum (soluble) : Heat treated at 200 ° C., Blaine specific surface area 10000 cm ² / g or more “Active silica” α. Silica fume: BET, manufactured by Efaco, Egypt
Specific surface area 19.2 m ² / g β. Fired ash of silicified wood: BET specific surface area 1.0 m ² / g γ. Metakaolin: Brand name “SEM clay” manufactured by Kanto Bentonite Mining Co., Ltd. Blaine specific surface area 8050 cm ² / g
Δ. Aerosil: Nippon Aerosil Co., Ltd., BET specific surface area 160 m ² / g “Pozzolanic substance” I. Fly ash: Tohoku Electric Power Co., Inc. fly ash (Brain specific surface area: 3500 cm ² / g), Blaine specific surface area 64
. 00cm ² / g to, ground II acid clay of heat-treated product: was calcined at 1000 ° C. the bentonite Mining Co. acid clay Kanto, Blaine specific surface area 550
. 0 cm ² / g, ground to III zeolite heat-treated product: Kanto bentonite Mining Co. zeolite G35 dishes and baked at 1000 ° C., those that have been ground to a Blaine specific surface area of 6500 cm ² / g IV Kaolin:. Ltd. Kanto Bentonite Mining Co. Product name "SE
"M clay" ground to a specific surface area of 8050 cm ² / g V. Diatomaceous earth: "Celite F" manufactured by Kanto Bentonite Mining Co., Ltd.
C "crushed to a specific surface area of 7000 cm ² / g VI. Blast furnace slag powder: Nippon Steel Chemical Co., Ltd., specific surface area of 4500 cm ² / g

Example 1 A high-performance water reducing agent was added to 100 parts by weight of cement and 135 parts by weight of sand.
Carbonates, lignin sulfonates are mixed at different mixing ratios, kneading and adjusting the amount of water, kneading the mortar,
The flow was measured and the amount of mixing water at that time was also recorded. The results are shown in Tables 1 and 2. Mix the mortar using a mortar mixer, put a part of sand, mixing water and a high-performance water reducing agent into a kneading bowl, and stir at low speed within 30 seconds while cement, carbonate, etc. and lignin sulfonic acid. The mixture of salt and the remaining sand were charged. After continuing kneading at a low speed for another 60 seconds, stirring was stopped once, the mortar attached to the pot was scraped off with a spatula, and then kneading was performed at a high speed for 60 seconds. The mortar flow is measured by JI
Performed based on SR5201. That is, the diameters of the bottom and top sides are 12 cm and 7 cm, respectively, and the height is 10 c.
The spread of the mortar when the flow cone was pulled out on a glass plate using a cone of m was measured immediately after mixing. At this time, the temperature in the test chamber was 20 ± 2 ° C.

[0034]

[Table 1]

[0035]

[Table 2]

Tables 1 and 2 show that when a high-performance water reducing agent and a carbonate were added (Experiment Nos. 1-1 to 1-6, Comparative Example), lignin sulfonate was added (Experiment Nos. 1-1 to 1-6). No.1-13
~ 1-18, Example) shows a flow value equal to or higher than the former with a smaller amount of water, indicating that the water reduction rate is improved. When the amount of the high-performance water reducing agent is 0.3 parts by weight or more with respect to 100 parts by weight of cement, a remarkable water reducing effect starts to appear, and it is shown that it is more preferable when the amount is 0.6 parts by weight or more. Further, even if it is added in excess of 2.5 parts by weight, the water reducing effect is not so much improved and reaches a plateau. When the amount of carbonate etc. was changed while the amount of high-performance water reducing agent and the amount of ligninsulfonate were fixed (Experiment No.1-19,
In Comparative Examples and Experiments Nos. 1-20 to 1-25, Examples), as the amount of addition of carbonates and the like increased, the same or more flow was developed with a smaller amount of water.
It becomes larger when the amount is 0.1 parts by weight or more with respect to parts by weight. On the other hand, when the amount exceeds 0.6 parts by weight, the method of improving the water reducing effect becomes small, and after kneading, stiffness occurs on the surface after a while, and a phenomenon that the flow does not recover even after re-kneading is observed. It is preferably used in an amount of 0.6 parts by weight or less.

When the amounts of the high-performance water reducing agent and the carbonates were kept constant and the amount of ligninsulfonate was changed, the effect began to appear at 0.05 parts by weight or more with respect to 100 parts by weight of cement. It is preferably at least 0.1 part by weight (experiment
Nos. 1-26 to 1-31, Examples). If the amount exceeds 0.5 parts by weight, the water reducing effect is reduced, and the setting of the cement may be delayed. Furthermore, when the type of carbonates and ligninsulfonate were changed (Experiment Nos. 1-32 to 1-36, Examples), the degree of the water reducing effect was different, and when tripolyphosphate was used. Is somewhat less effective. In addition, in the cement manufactured by Company A, a certain amount of water reducing effect was observed by adding a high performance water reducing agent and a carbonate (Experiment Nos. 1-1 to 1-12, Comparative Examples).
Almost no effect was seen with cement made by Company B (Experiment No.1
-37, Comparative example). However, when lignin sulfonate was added in combination (Experiment Nos. 1-38 to 1-43), it was found that the water reduction rate was increased similarly to the cement made by Company A, and that the difference due to the lot number and brand of the cement could be eliminated. .

Example 2 Gypsum, activated silica, and pozzolanic substances were arbitrarily combined using the basic concrete composition shown in Table 3, and were replaced with sand so that the total volume would be equal by changing the type and amount of addition. .

[0039]

[Table 3]

The concrete was kneaded to adjust the amount of water so that the slump was almost constant, and kneaded for 40 liters. At this time, the amount of mixing water used was recorded and converted to a water-cement ratio, and a cylindrical specimen of φ10 × 20 cm was prepared. It was measured. Table 4-
It is shown in Table 6. The concrete was kneaded in a test room at 20 ± 2 ° C. using a planetary forced kneading mixer. After adding crushed stone, sand, and cement (mixed with an admixture containing gypsum, etc.), knead the high-performance water reducing agent with stirring, add a solution dissolved in the total amount of water, and mix for 2 minutes. Was. The steam curing was carried out for 4 hours, the temperature was raised to 75 ° C. over 3 hours, and the temperature was maintained for 4 hours. After that, the steam valve was stopped, and cooling was performed in the curing tank until the next morning.

[0041]

[Table 4]

[0042]

[Table 5]

[0043]

[Table 6]

Tables 4 to 6 show that the addition of the high-performance water reducing agent of the present invention and an admixture containing a carbonate or the like and ligninsulfonate makes it possible to obtain a concrete with the same slump. The water-cement ratio can be reduced by 1 to 2% as compared with the case of using only salt or the like, and a strength increase more than that can be obtained (see Experiment No. 2-1 and Experiment No. 2-12). When the admixture of the present invention is used in combination with gypsum, a higher strength than the strength expressing effect by reducing the water cement ratio can be obtained. Among the gypsums, type II anhydrous gypsum tends to lower the water-cement ratio and exhibits excellent effects in strength (Experiment Nos. 2-2 to 2-8 and Experiment Nos. 2 to 13) See 2-19).

When the admixture of the present invention and active silica are used together, the strength increases as the amount of active silica increases, but as the amount of active silica increases, more water is required to obtain the same slump. Therefore, the strength tends to plateau.

In addition, even when the admixture of the present invention and the pozzolanic substance are used in combination, an increase in strength beyond the effect of a reduction in the water-cement ratio is observed (Experiment Nos. 2-43 to 2-52, Comparative Examples and Experiments).
No. 2-53 to 2-62, see Examples).

Extremely high strength can be obtained even when the admixture of the present invention and the gypsum, active silica and pozzolanic substances are added together in any proportion (see Experiments Nos. 2-63 and 2-70).

[0048]

By using the cement admixture of the present invention and the cement composition using the same, the lot number of the cement used can be improved. Regardless of the brand or brand, the water reducing rate of the conventional high-performance water reducing agent can be greatly improved, and high strength can be obtained. Therefore, if the design strength is constant,
Because the amount of high-performance water reducing agent used and the amount of cement used, and the amount of gypsum, activated silica, and pozzolanic substances can be reduced,
Not only is it possible to produce concrete more economically, but also there are advantages such as suppression of heat of hydration.

Claims (5)

[Claims] 1. A high-performance water reducing agent, one or more of sodium or potassium carbonate, sodium or potassium hydrogen carbonate, tripolyphosphate, and ammonium hydrogen carbonate, and lignin sulfonate. A cement admixture characterized by the following. 2. The cement admixture according to claim 1, wherein the cement admixture contains one or more of gypsum, activated silica, and a pozzolanic substance. 3. A cement composition comprising a cement and the cement admixture according to claim 1 or 2. 4. A high-performance water reducing agent in an amount of 0.3 to 2.5 parts by weight in terms of solid content, 100 parts by weight of cement, sodium or potassium carbonate, sodium or potassium bicarbonate, and tripolyphosphoric acid. 0.05 to 0.6 parts by weight of one or more of a salt and ammonium bicarbonate,
Lignin sulfonate is 0.05 to 0.5 in terms of solid content.
A cement composition characterized by containing by weight. 5. One or more of gypsum, activated silica and pozzolanic substances are each converted to CaSO ₄ by 1 to 5%.
The cement composition according to claim 4, comprising 15 parts by weight, 1 to 12 parts by weight, or 2 to 15 parts by weight.