JPS6038347B2 - cement composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cement composition, particularly a cement composition comprising Bortland cement in which an anionic surfactant and a boron compound are present.

The purpose is to improve the fluidity of cement mortar, concrete, etc. Conventionally, in order to improve the fluidity and strength development of cement mortar or concrete using Boltland cement, it has been done to add a small amount of anionic surfactant. can increase liquidity, but
After that, it rapidly decreases, so, for example, in the pump crete construction method, there is a drawback that the workability of the construction decreases significantly. In order to improve these drawbacks, a method of adjusting the timing of addition of surfactants has been proposed, but this is not a fundamental countermeasure, and improvements are desired.

The present invention solves these drawbacks and provides a cement composition that improves the fluidity of cement mortar and concrete by incorporating small amounts of an anionic surfactant and a boron compound into Bortland cement. It is something.

That is, the present invention contains Boltland cement, an anionic surfactant, and a boron compound, and the boron compound is 0.01 to 2% by weight in terms of boron element based on Boltland cement. It is characterized by

In the present invention, an anionic surfactant and a boron compound are used together in Bortland cement, and the content of the boron compound is particularly important.

That is, it is necessary to adjust the content to 0.01 to 2% by weight in terms of boron element based on Bortland cement. The reason for this is that if the amount of boron compound added is less than 0.01% by weight in terms of boron element, the effect will be small, and if it is added in excess of 2% by weight, the hardening of Bortland cement will be significantly delayed. However, the object of the present invention cannot be achieved. Types of boron compounds include acids such as boric acid, metaboric acid, orthoboric acid, alkali borates such as sodium borate and potassium borate, borate minerals such as borax and carnit, ammonium perborate, potassium perborate,
Perborates such as sodium perborate and all boron compounds such as ammonium borate, calcium borate, aluminum borate, strontium borate can be used.

Among these boron compounds, the most preferred are hydrophobic boron compounds. As anionic surfactants, all conventionally known cement dispersants can be used, but the active ingredients include lignin sulfonate, 6-naphthalene sulfonic acid formaldehyde condensate salt, sulfonated Examples include melamine formaldehyde condensate salts, oxycarboxylate salts, and polyalkylarisulfonate salts.

Further, specific examples of these products include Nisso Master Builders, Pozorisu, Kao Soap Co., Mighty, Showa Denko Co., Melmento, Fujisawa Pharmaceutical Co., Ltd., and Paricu, Takemoto Yushi Co., Ltd., and Pole Fine. In the present invention, these surfactants can be used in amounts generally used in Bortland cement. Specifically, about 0.1 to 1% by weight of the active ingredient based on Boltland cement is sufficient. Also, as Boltland Cement,
Common, early-strength, ultra-early-strength, and white boltland cements, mixed cements containing silica, fly ash, blast furnace slag, etc., are examples.

When kneading the cement of the present invention, it is preferable that the anionic surfactant is added simultaneously with the boron compound or added prior to the boron compound. In particular, the anionic surfactant and the boron compound are preferably mixed in advance. It is most preferable to add it.

On the other hand, the method of adding a boron compound to Bortland cement, pouring water, and then adding an anionic surfactant has a smaller effect than the above method. As explained above, the cement composition of the present invention is made by adding a small amount of an anionic surfactant and a boron compound to Bortland cement, and when this cement composition is used, the fluidity immediately after drilling is improved. This has the effect of improving the flow rate and minimizing the subsequent decrease in fluidity. The present invention will be further explained below with reference to Examples.

Example 1 520 parts of ordinary Voltland cement (parts are parts by weight, the same applies hereinafter), 312 parts of water, 104 parts of plump standard sand, and Kao soap as an anionic surfactant. Naphthalene sulfonic acid formaldehyde condensate salt) and the reagent boric acid as a boron compound were dissolved in the water used as shown in Table 1 and mixed to form a mortar.

The results of measuring the flow and compressive strength of this mortar over time are the first
Shown in the table. The amount of "Mighty 150" added is expressed in terms of solid content, and the amount of boric acid added is expressed in terms of elemental boron. As is clear from Table 1, when an anionic surfactant and a boron compound are used in combination, the change in flow (fluidity) over time is small and there is an effect of improving fluidity.

Table 1 Next, in this example, a similar experiment was conducted using sodium borate and potassium borate instead of boric acid, and the results were not much different from the above.

Example 2 Except for using Nisso Master Builders' product name "Pozolith No. 8" (main component lignin sulfonate) as the anionic surfactant and borax as the boron compound, and using 333 parts of water. Measurement was carried out in the same manner as in Example 1.

The results are shown in Table 2. In addition, "Pozolith No. 8"
The amount of borax added is expressed in terms of solid content, and the amount of borax added is expressed in terms of elemental boron. Table 2 Example 3 Experiment No. of Example 1. At the blending ratio of No. 4, the flow over time and compressive strength were measured in the same manner as in Example 1, except that the order of addition of "Mighty" and boric acid was changed as shown in Table 3.

The results are shown in Table 3. Table 3

Claims (1)

[Claims] 1 Contains Portland cement, an anionic surfactant, and a boron compound, and the boron compound is 0.01 in terms of boron element relative to Portland cement.
~2% by weight of a cement composition.