JPS5895684A - Cement whitening prevention - 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] The present invention relates to a method for preventing efflorescence of cement.

Cement efflorescence occurs as follows. When cement hardens by reacting with water, a large amount of hydroxyl lucium is produced as a by-product. It is said that the amount of by-product of calcium hydroxide amounts to as much as 26% of the amount of cement if the reaction proceeds completely. Calcium hydroxide, a by-product, is dissolved in water and transported to the surface, and the precipitate is efflorescence. Furthermore, this efflorescence is converted to lucium carbonate by carbon dioxide gas in the air, and becomes efflorescence that is insoluble in water.

Conventionally, various additive mixtures to cement have been proposed to prevent this efflorescence, but these have not been sufficient. Furthermore, although a surface treatment agent is applied to the cement surface to make it waterproof, it cannot prevent the cement from cracking and causing efflorescence.

An object of the present invention is to provide a method for reliably preventing efflorescence.

In the present invention, immediately after cement construction, the cement surface 1
The invention is characterized by applying 10 g or more of a titanium-based coupling agent per m'', which significantly prevents efflorescence. It is speculated that this is because the cement compact is densified to narrow the water passage during drying during cement hardening, which prevents the movement of lucium hydroxide, and also makes calcium hydroxide hydrophobic and prevents it from becoming water-solubilized. There is.

Various admixtures have been conventionally used to modify the physical properties of cement compounds. Examples include AE agent 1 water reducer, foaming agent, retardant, accelerator, waterproofing agent, adhesive, antifreeze agent, etc. These admixtures may be mixed into cement in carrying out the present invention.

Applications of cement that dislike efflorescence include architectural finishing materials, joint materials for tiles, bricks, blocks, masonry, etc., artificial stones, color #I covering materials, etc., and the present invention is applicable to these materials. It can be carried out in conjunction.

Immediately after cement construction, if the amount of titanium-based coupling agent applied is less than 10 g per 1 m3 of the cement surface, the efflorescence prevention effect will be significantly inferior.

The inventor of the present invention conducted an experiment as follows and reported the experimental results in Table 1. As a general cement to prevent efflorescence, 8 parts by weight of carbon black as a black inorganic pigment was added to 100 parts by weight each of ordinary Portland cement and white cement to clarify the detection of efflorescence, and then water was added. The mixture is then kneaded and spread on an asbestos cement board to a thickness of about 5 mm. Immediately after this construction, a 5-10% emulsion of a titanium-based coupling agent is spray applied to the surface of the cement. This creates a sample. Titanium-based coupling agents include KR-TTS and KR-2.
01 (both are trade names manufactured by Kenrich Petrochemicals, Inc. in the United States). KR-TTS is Improvil tri-instearoyl titanate)'t''&D, KR-201 is di-instearoyl ethylene titanate. In Table 1,
The freeze-thaw test involves leaving the sample indoors for 1 hour, then keeping it overnight at 15°C in a freezer, exposing it outdoors from the next morning until the evening, drinking water in the evening, and then immediately exposing it to 15°C. The sample was kept in a refrigerated car under C atmosphere overnight, and the same steps were repeated to conduct the experiment. In the outdoor exposure test, the #J sample is left indoors for one hour in winter, and then left outdoors for exposure. Detection of efflorescence is done visually. According to this experiment, it is clear from the results in Table 1 that the application of the titanium-based coupling agent of the present invention has an effect of suppressing efflorescence.

There is no problem in carrying out the present invention by mixing a titanium-based coupling agent with a conventional surface treatment agent for water treatment, waterproofing, coloring, etc.

As shown in Table 1 and above, according to the present invention, efflorescence of cement can be extremely easily prevented by applying a titanium-based coupling agent to the cement surface immediately after cement construction.

Agent: Patent Attorney: Kei Nishikyo

Claims (1)

[Claims] A method for preventing efflorescence of cement, which comprises applying 10 g or more of a titanium-based coupling agent to a surface of 1 m of cement immediately after cement construction.