JP3179909B2 - Manufacturing method of hardened cement - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a hardened cement used as a building material.

[0002]

2. Description of the Related Art Hardened cement bodies are used in various fields, but the demand is remarkably large especially for building materials. Therefore, it is very important to improve the productivity while maintaining the strength in the production of a hardened cement body. In particular, the press molding method attracts attention because it can efficiently produce a three-dimensional molded product. Have been.

When a cement composition is molded by a press molding method to produce a hardened cement, if a large amount of reinforcing fibers are added to the cement composition, the fibers may be cut at the time of molding, resulting in poor moldability. is there. For this purpose, the moldability is enhanced by using a cement composition with a small amount of reinforcing fiber added, or the moldability is enhanced by blending a large amount of methylcellulose (MC) such as hydroxypropylmethylcellulose as a molding aid. In addition, a water reducing agent is added to lower the water mixture ratio to enhance the formability.

[0004]

However, even if MC or a water reducing agent is used, the effect of enhancing the moldability cannot be sufficiently obtained. For this reason, if the amount of the reinforcing fiber added is reduced, the hardened cement body cannot be obtained. Decreases strength, for example, when forming eaves tiles etc. with hardened cement, cracks and chips are likely to occur during transportation and construction, and large costs must be spent on packaging to prevent cracks and chips There was a problem.

[0005] The present invention has been made in view of the above points, and an object of the present invention is to provide a method for producing a hardened cement body capable of improving moldability without reducing strength.

[0006]

Means for Solving the Problems A method of manufacturing a hardened cement body according to the present invention, e with including modified polycarboxylic acid
The present invention is characterized in that a cement composition to which a non-ionic surfactant is added is press-molded, and the molded product is cured and hardened.

Hereinafter, the present invention will be described in detail. Cement composition is prepared by mixing the cement with aggregate, reinforcing fiber, colorant, etc. as necessary and kneading with water.As the cement, usually Portland cement, slag cement, alumina cement, Arbitrary materials such as early-strength cement can be used. The aggregates include silica, silica powder, silica sand, fly ash, slag,
Crushed stone or the like can be used. As the reinforcing fiber, besides asbestos, polypropylene fiber, vinylon fiber, acrylic fiber, pulp, carbon fiber, cotton, hemp, metal fiber and the like can be used. Further, as a coloring agent, iron black, carbon black, chromium oxide, or the like can be used.

In the present invention, the moldability of press molding is enhanced by blending a modified polycarboxylic acid with the cement composition. That is, when the modified polycarboxylic acid is blended, cement, aggregate, reinforcing fibers and the like can be dispersed stably to reduce secondary aggregation, reduce resistance between material components, and perform press molding. Some can increase elongation, and can improve moldability without having to reduce the amount of reinforcing fibers added.

As the modified polycarboxylic acid, an ether-modified or ester-modified polymethacrylic acid can be used. For example, as a commercial product, “SF230G” manufactured by Sanyo Chemical Industries, Ltd. can be used. Here, unmodified polycarboxylic acid has poor stability even when cement, aggregate, reinforcing fibers, and the like are dispersed, and may be re-agglomerated.In the present invention, therefore, a modified polycarboxylic acid is used. Things. The amount of the modified polycarboxylic acid added is 0.05% based on the solid matter of the cement composition.
~ 0.5% by weight is preferred. If the addition amount is less than 0.05% by weight, the effect of improving the moldability and strength by blending the modified polycarboxylic acid cannot be sufficiently obtained. Conversely, if the addition amount exceeds 0.5% by weight, the setting delay of the cement becomes large due to the modified polycarboxylic acid, and it becomes difficult to use the cement practically. A styrene / maleic acid copolymer polyethylene oxide adduct can be used as a material capable of obtaining the same effect as the modified carboxylic acid. Further, a salt of a modified polycarboxylic acid can also be used.

When the modified polycarboxylic acid is added to the cement composition as described above, the air tends to be entrained in the system and the specific gravity of the cured cement body tends to decrease. So book
The invention, by adding ether a nonionic surfactant and (ether type nonionic surfactant), so as to collapse the bubbles while preventing the entrainment of such air, and to keep a high specific gravity. As the ether-based nonionic activator, a polyoxyalkyl ether or the like can be used, and as a commercially available product, “Cedran FF180” manufactured by Sanyo Chemical Industries, Ltd. can be used. Even when the ether-based nonionic surfactant is added in excess of 0.1% by weight based on the solid content of the cement composition, the effect of increasing the specific gravity is not increased, so the amount of the ether-based nonionic surfactant added is 0.1 based on the solid content of the cement composition
It is preferably set to not more than weight%. It may be used by San Nopco Co., Ltd. "Fomasuta PC" as being able to obtain this ether nonionic surfactants equivalent effect.

Thus, first, solids such as cement and other aggregates, reinforcing fibers, and coloring agents are mixed, and further, a modified polycarboxylic acid, an ether-based nonionic activator, and, if necessary, MC are blended and mixed. Then, a cement composition for press molding is prepared by adding a liquid such as water and kneading with a kneading machine, and after pressing the cement composition with a press molding machine, steam curing and curing. By doing so, it is possible to produce a hardened cement body. As described above, when the cement composition is press-molded, since the modified polycarboxylic acid is blended in the cement composition, the material elongation at the time of pressing increases, the formability increases, and the patterning by press molding is performed. Can be facilitated and productivity can be improved. In addition, since the moldability can be enhanced by blending the modified polycarboxylic acid, it is not necessary to reduce the blending of the reinforcing fibers, and the strength of the hardened cement can be secured by blending the reinforcing fibers.

[0012]

The present invention will now be illustrated by examples. (Example 1 , Comparative Examples 1 to 5 ) Cement compositions were prepared by mixing and kneading the components in the composition shown in Table 1 , and then press-molded, followed by steam curing to produce hardened cement bodies. "SF230G" manufactured by Sanyo Chemical Industries, Ltd. was used as the modified polycarboxylic acid, and "Cedran FF180" manufactured by Sanyo Chemical Industries, Ltd. was used as the ether nonionic surfactant.

In the press forming, the elongation of the material was measured to evaluate the formability. Further, the bending strength and the absolute specific gravity of the obtained hardened cement were measured. Table 1 shows the results. The elongation was measured using a 150 g cement composition in the form of a cylinder having an outer diameter of 55 mm.
The outer shape after the press 0kgf / cm ^2, 5 seconds was carried out in Tsu by that measure.

[0014]

[Table 1]

[0015]

As shown in Table 1 , it is confirmed that the incorporation of the modified polycarboxylic acid can increase the elongation during pressing to enhance the formability, and can also obtain a high bending strength. It is also confirmed that the addition of an ether-based nonionic activator can keep the absolute specific gravity high.

[0017]

As described above, according to the present invention, a cement composition containing a modified polycarboxylic acid is press-molded, so that cement and the like are stably dispersed by the modified polycarboxylic acid to reduce secondary agglomeration. However, it is possible to increase the elongation of the material at the time of press molding, and it is possible to enhance the moldability of the cement composition without reducing the amount of the reinforcing fiber, and The strength of the hardened cement can be kept high by blending the fibers. Then, the modified polycarbo is added to the cement composition.
When acid is added, air is entrained into the system and cement hardens.
The specific gravity of the compound tends to decrease, but the present invention
Since a non-ionic surfactant was added,
Can prevent entrainment of air and crush air bubbles,
The specific gravity can be kept high.

──────────────────────────────────────────────────の Continuation of the front page (51) Int.Cl. ⁷ identification code FI C04B 28/02 C04B 28/02 (58) Field surveyed (Int.Cl. ⁷ , DB name) B28B 3/02 B28B 1/52 C04B 24/26

Claims (1)

(57) [Claims] 1. An ether containing a modified polycarboxylic acid.
A method for producing a hardened cement, comprising press-forming a cement composition to which a non-ionic surfactant is added , and curing and hardening the formed product.