JPS6038348B2 - cement composition - Google Patents

Description

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

An object of the present invention is to improve the deterioration of the fluidity of cement mortar, concrete, etc. over time. Traditionally,
Anionic surfactants are added to Boltland cement mortar, concrete, etc. to improve fluidity and strength development.

According to this method, the fluidity can be improved immediately after kneading, but it rapidly decreases thereafter, and for example, in the Pompocrete construction method, there is a drawback that the workability is significantly lowered. In order to solve this drawback, a method has been proposed in which the timing of addition of the surfactant is adjusted, but this method does not solve the fundamental problem.

The present invention solves these drawbacks by using three components of an anionic surfactant, a carbonate compound, and a hoken compound in Bortland cement.
The object of the present invention is to provide a cement composition that improves the fluidity of cement mortar, concrete, etc. immediately after mixing and prevents its deterioration over time. That is, in the present invention, 0.01 to 2% of anionic surfactant is added to Bortland cement.
, a cement composition containing 0.01 to 2% of a carbonate compound in terms of carbonate ion and 0.01 to 2% of a boron compound in terms of boron element.

In the present invention, as the anionic surfactant, one that is usually mixed in cement can be used, and the amount thereof is preferably in the range of 0.01 to 2% based on Bortland cement.

The reason is that if it is less than 0.01%, the initial fluidity is insufficient, and if it exceeds 2%, the hardening of the cement will be delayed.
The strength may decrease. The active ingredients of anionic surfactants include lignin sulfonate, 3-naphthalene sulfonic acid formaldehyde condensate salt, melamine sulfonic acid formaldehyde condensate salt, oxycarboxylic acid or its salt, polyalkyl sulfosate. etc.

Specific examples of these include Nisso Master Builders column with the product name "Pozorisha Kao Soap", "Mightyha Showa Denko" product name, and "Parikha Takemoto Oil" product name "Pole Fine". In addition, carbonate compounds have a carbonate ion equivalent of 0.01 to 2 for Bortland cement.
%, and if this value is less than 0.01%, the effect is small;
Also, if it is added in excess of 2%, the false coagulation phenomenon becomes noticeable.
Initial fluidity decreases, hardening of cement is significantly delayed, and initial strength is insufficient. Types of carbonate compounds include alkali carbonate salts such as sodium carbonate and potassium carbonate, alkali bicarbonate salts such as sodium bicarbonate and potassium bicarbonate, ammonium carbonate, ammonium bicarbonate, and various carbonate minerals.

Among these carbonate compounds, the most preferred are water-soluble carbonate compounds. In addition, the boron compound is 0.01 to 2 in terms of boron element for Boltland cement.
%, and if this value is less than 0.01%, the effect will be small, and if it is added in excess of 2%, the hardening of the cement will be significantly reduced.

Boron compounds include boric acid, sodium borate such as metaboric acid, alkali borate such as potassium borate,
Borate minerals such as borax and carnit; perborates such as ammonium perborate, potassium perborate, and sodium perborate; and all boron compounds such as ammonium borate, calcium borate, aluminum borate, and strontium borate. It is possible.

Among these boron compounds, the most preferred are water-soluble boron compounds. Boltland cements include ordinary, early-strength, ultra-early-strength, medium-strength, and white boltland cements, as well as mixed cements such as silica cement, fly ash cement, and blast furnace cement.

When kneading and mixing the cement of the present invention, the anionic surfactant, carbonate compound, and boron compound may be mixed in advance and added, or they may be added at the same time. As explained above, the present invention is a cement composition containing specific amounts of an anionic surfactant, a carbonate compound, and a boron compound in Bortland cement, which is used to make cement mortar or concrete. In this case, the fluidity immediately after kneading was compared when only an anionic surfactant was added, when an anionic surfactant and a carbonate compound were added, or when a boron compound was added to an anionic surfactant. This has the effect that the fluidity is significantly improved, the subsequent decrease in fluidity is small, and the strength development is improved.

In the specification of the present invention, all percentages and the like are expressed on a weight basis.

The present invention will be further explained in detail with reference to Examples below.

Example 1 Ordinary bolt land cement 52 foundation, Tohoho standard sand 104
Ikarigun, 312 parts of tap water, Kao Soap Co., Ltd. product name "Mighty 150" (main component 8 naphthalene sulfonic acid formaldehyde condensate salt) as an anionic surfactant, boric acid as a boron compound, and carbonic acid as a carbonate compound. Sodium was dissolved in the water used in the proportions shown in Table 1, and mortar was mixed.

Table 1 shows the measurement results of the flow value and compressive strength over time of this mortar. Note that the amount added to "Mighty 150" is expressed in terms of the soil type, the amount of boric acid added is expressed in terms of elemental boron, and the amount of sodium carbonate is expressed in terms of carbonate ions. The mortar mixing method uses the JIS R-5201 machine mixing method, and the temporal flow (table flow) is based on JISR-520.
1, and the compressive strength was determined according to the mortar strength test method of JISR-5201. Experiment No. 5-7
is an example of the present invention. As is clear from Table 1, the fluidity of the examples of the present invention immediately after kneading is high, and the change in fluidity over time is small. Table 1 Example 2 Example 1 Experiment No. At the blending ratio of No. 6, the flow over time and compressive strength were measured in the same manner except that sodium carbonate was changed to the carbonate compound shown in Table 2.

The results are shown in Table 2. Table 2 As shown in Table 2, all carbonate compounds have the effect of preventing a decrease in fluidity.

Example 3 Example 1 Experiment No. At the blending ratio of No. 6, the flow over time and compressive strength were measured in the same manner except that boric acid was changed to the boron compound shown in Table 3.

The results are shown in Table 3. Table 3 As shown in Table 3, the effect of preventing a decrease in fluidity is the same even if the boron compound is changed.

Example 4 Ordinary bolt land cement 52 foundations, Toman standard sand 104
Ikarikuni, tap water 312 parts and boric acid as boron element 0
．． 45 parts, sodium carbonate as carbonate ion 1.47
and the anionic surfactant shown in Table 4 were dissolved in the water used and kneaded into mortar.

Furthermore, experiment no. Nos. 21 to 23 are formulations in which boric acid and sodium carbonate are not added. Table 4 shows the temporal flow value and compressive strength measurement results of this mortar.

Table 4

Claims (1)

[Claims] Based on Portland cement, anionic surfactant is 0.01 to 2% by weight, carbonate compound is 0.01 to 2% by weight in terms of carbonate ion, and boron compound is 0.01% in terms of boron element. A cement composition containing ~2% by weight.