JPS61158850A - Cement composition for underwater construction - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to the improvement of cement compositions that are cast directly in water or in places with a lot of water, and particularly relates to the improvement of the kneading properties of cement compositions. be.

[Conventional technology]

In order to prevent the cement from dispersing into the water, a construction method has been developed that uses a cement composition containing a water-soluble polymer additive to give it viscosity when carrying out construction work in water or in areas with a lot of water. for example.

West German Patent No. 2326647 discloses that cement can be diffused into water by adding polymeric additives such as cellulose ether and polyacrylamide, which improve water retention and provide resistance to water erosion. As stated above, this can be prevented. Further, 1% Publication No. 57-3971 relates to an underwater concrete casting method, and shows an example in which polyacrylic rhodium is used as a concrete formulation.

However, although there are polymers that have such a thickening effect,
The fluidity of cement compositions is severely impaired, making it difficult to pump. On the other hand, in order to improve the fluidity and self-leveling properties of fresh concrete, concrete water reducers, cement dispersants, or It is well known that admixtures called concrete fluidizers are used. For example, lignin sulfonate-based, oxycarboxylic acid-based, allyl sulfonate-based, polyol-based, naphthalene sulfonate-based, Water reducing agents such as polycyclic aromatic sulfonate salts and melamine sulfonate salts have been used (Japanese Patent Application Laid-Open No. 49-50017, Japanese Patent Application Laid-Open No. 54-32525, etc.).

Also, patent application No. 59-107461 filed by the present inventor.
As described in the issue, hydroxyethyl cellulose (HEO), polyethylene oxide (PKO) and a water reducing agent are blended in a cement composition for underwater placement,
There are also examples of improved liquidity.

As described above, much research has been done on cement compositions that have good fluidity and are effective in preventing the diffusion of cement into water, and many applications regarding such cement compositions have been published.

[Problem that the invention seeks to solve]

However, in all of the previously proposed cement compositions for underwater casting as described above, water-soluble polymers are used to provide viscosity in order to prevent cement from dispersing into water. A water-soluble polymer having a high viscosity must be added and uniformly mixed using a concrete mixer within a practical time (2 to 3 minutes).

Concrete used for general pouring is composed of multiple components such as cement, river sand, rice flour, water, and water reducing agents, but because of its low viscosity, it can be mixed uniformly in a relatively short time.

On the other hand, when blending a highly viscous water bathing polymer such as a cement composition for underwater casting, the high viscosity makes it difficult to mix uniformly in a short time, and cement compositions that are not mixed uniformly As a result of experiments, it became clear that its fluidity decreased and it did not fully demonstrate its original functions.

[Means for solving problems]

The present inventors have conducted studies to improve the crosstalk of underwater pouring cement compositions that contain high-viscosity water-soluble polymers. It was discovered that a cement composition for underwater casting having better kneading properties than K can be obtained by incorporating a wet penetrating agent, and the present invention was developed based on this finding.

That is, the present invention provides a cement composition for underwater casting containing a water-bathable polymer compound.
The present invention provides a cement composition for underwater casting, characterized in that 0.1 to 1 part by weight of a moisture penetrant is blended to 0.00 parts by weight.

The amount of the moisture penetrating agent blended into the cement composition for underwater casting of the present invention is 0.1 to 1 part by weight per 100 parts by weight of water in the cement composition. Suitable wetting penetrants include alkylnaphthalene sulfonates, dialkyl sulfosuccinates, polyoxyethylene octylphenol ether,
Dodecylbenzene sulfonate, polyoxyethylene lauryl ether, etc., all of which have the function of improving the kneadability and fluidity of cement compositions for underwater casting to which high-viscosity water-bathable polymers are added. .

Furthermore, in addition to a water-soluble polymer compound as a cement-aggregate separation preventing agent, the cement composition of the present invention may also contain a water-reducing agent, an antifoaming agent, a cement setting regulator, etc. can.

The water-bathable polymer compounds to be incorporated into the cement composition for underwater placement of the present invention include polyvinyl alcohol, polyacrylamide, polyethylene oxide, sodium polyacrylate, methylcellulose, ethylcellulose, hydroxyethylcellulose, hydroxyglobilcellulose, and hydroxypropyl. Water-soluble polymers such as methylcellulose, carboxymethylhydroxyethylcellulose, and cellulose ethers represented by these can be used. These water bathable polymers preferably have a high viscosity, and the viscosity (at 20°C) when dissolved in blended water is 1.
,000 to 100,000 cps is suitable.

〔Example〕

Next, the present invention will be specifically described with reference to Examples, but the present invention is not limited to these Examples.

Example 1 (Blend of cement composition) Portland cement 600 from Sumitomo Cement (c)
f river sand 1
200 f water
3001 admixture (mixture of water-soluble polymer and antifoaming agent) S, St wetting penetrant (the sum of this addition amount and water amount is 3
00-)-2d (Kneading method) Using a JIB type mortar mixer, put Portland cement, river sand and an admixture into the container and mix for 30 seconds, then add water in which the wetting and penetrating agent has been dispersed and mix for 150 seconds. and made raw mortar.

(Evaluation method) 0 The air volume of mortar is the "air volume" specified by Japan Housing Corporation [Quality Judgment Standards for Plastering Mortar Mixture Materials (Draft) JK]
Measured according to the test method.

The fluidity of the mortar was measured by the method of "7o-test" of J.K. SR5201.

(Test Results) The test results are shown in Table 1, and the following can be seen from the results: 0 (1) The degree of molar substitution (M, S, ) is 3.7.
For a mixture (admixture) of hydroxyethyl cellulose (abbreviated as HIO) with a 1% water bath solution viscosity of 1,600 cps and an antifoaming agent (admixture), when a wetting agent is used in combination, the air content of the mortar does not increase significantly, but the fluidity ( (2) When using the same wetting penetrant (Pellex 0T-P), the viscosities of 1% aqueous solutions of H]IiO in the admixture are different (1.600 cps and 4,050 cps). The improvement in fluidity due to the addition of cps) and a wetting penetrant is more pronounced in admixtures using high viscosity HIG.

This result shows that the cross-contamination of cement compositions containing high-viscosity water-soluble polymers tends to be non-uniform, and the use of a wetting agent enables uniform cross-contamination, greatly improving fluidity.
It seems that it depends.

Example 2 (Blend of cement composition) Portland cement 600 from Sumitomo Cement ■
f river sand
1200 f water
282 wLl admixture (mixture of water-soluble polymer and antifoaming agent) S, S as water reducing agent
18d-2m (Mixing method) Using a JIS type mortar mixer, put Portland cement, river sand, and an admixture into the container, mix for 30 seconds, first add water in which the wetting and penetrating agent has been dispersed, and mix for 90 seconds. A water reducing agent is added to the mixture and kneaded for 60 seconds to make green mortar.

(Evaluation method) The air content and fluidity of mortar are measured by the method described in Example 1.

(Test Results) The test results are shown in Table 2, and the following can be seen from the results.

That is, the admixture (M, 8.5.7, 1% aqueous solution viscosity 160
Wet penetrant (Pellex 0 cps mixture of HBO and antifoam agent) and water reducer were added to the cement composition.
Although the raw mortar obtained by using T-P, Pellex NBI, ) did not show an increase in air content,
An improvement in fluidity (flow value) was observed.

〔Effect of the invention〕

In the cement composition for underwater casting of the present invention, the mixing of the wetting and penetrating agent improves crosstalk and improves fluidity, thereby improving workability such as pumping. or,
Since the fluidity is improved, the amount of blended water can be reduced and the curing strength can be increased.

Claims (1)

[Claims] 1. In a cement composition for underwater casting containing a water-soluble polymer compound, 0.1 to 1 part by weight of a moisture penetrant is added to 100 parts by weight of water in the cement composition. 1. A cement composition for underwater casting, characterized by comprising: 2. The moisture penetrant is selected from alkylnaphthalene sulfonate, dialkyl sulfosuccinate, polyoxyethylene octylphenol ether, dodecylbenzene sulfonate and polyoxyethylene lauryl ether. Cement composition for underwater pouring.