JPS5851902B2 - Rapid hardening method of cement - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for rapidly curing cement, which gels cement in a few seconds to about 10 seconds and exhibits particularly excellent water-stopping effects.

Traditionally, water glass-based grouts have been mainly used as water-stop grouts, but recently rapid hardening cement grouts have been used due to the problems of post-construction PH management and pollution caused by groundwater contamination. has started to attract attention.

However, commercially available quick-hardening cement or cement containing quick-hardening cement has a quick gelling time of 60%.
Since the curing time is about seconds, sufficient handling time (pot life) is required, and therefore, it is difficult to cure rapidly in construction work such as water stoppage, which is in a fluid state.

In order to solve this problem, a slurry containing cement rapidly hardening material as an active ingredient is prepared as Solution A, and a slurry containing cement as an active ingredient is prepared as Solution B, and the two solutions are combined continuously or intermittently during construction. A method has been proposed in which the cement is hardened by letting the liquid mix. However, in this method, the presence of a setting retarder is inevitable in order to ensure that liquid A has sufficient kneading properties. Therefore, even if the two liquids are combined, the above problem does not occur. No point was resolved.

The purpose of the present invention is to improve this, by making full use of the kneading properties of Part A, and without adversely affecting the kneading properties and kneading properties of Part B. When both liquids are combined, it gels in about 10 seconds from a few seconds. The gist of the method is to make liquid B contain aluminum sulfate in an amount of 0.5 to 5% by weight based on cement.

The method of the present invention will be explained in detail below.

The cement rapid hardening material used for liquid A contains Ca as a chemical component.
It contains 02A1203 and SO3 as active ingredients, for example, 12CaO・7A403°11Ca
0.7A1203.CaF2. CaO-Al2O3゜3
It is a mixture of calcium aluminate such as CaO-A1203 and an inorganic sulfate such as gypsum or sodium sulfate, or a simultaneous melt thereof, and can be used regardless of crystal form, but in particular 12 CaO-7A71203 or 11
A mixture of a material having a composition of Ca0.7A1203.CaF2 melted at high temperature and then rapidly cooled to form an amorphous material and hard stone has the highest rapid hardening.

A preferred ratio of calcium aluminate and inorganic sulfate is 0.5 to 1.5 times the weight of the latter to the former.

In addition, a small amount of organic hydroxycarboxylic acids such as citric acid, tartaric acid, and phosphoric acid, sucrose, EDTA used in chemical analysis, and known setting retarders such as sodium carbonate and potassium carbonate are added to liquid A. It is preferable to leave the mixture for a while in order to ensure that the liquid A has sufficient kneading properties.

For example, when potassium carbonate and citric acid are used together as setting retarders, 5 weight 9
Hereinafter, preferably at a blending amount of 0.3 to 4 weight, liquid A can be prevented from condensing while maintaining appropriate fluidity for at least 20 minutes after being prepared.

Next, liquid B is a paste, mortar, or concrete, and aluminum sulfate is present in an amount of 0.5 to 5 weight based on the cement content.

The reason for this is related to the concentration of both A and B, but at the maximum concentration of both A and B that can maintain their fluidity, 0.
If it is less than 5% by weight, even if both liquids are mixed, it will not be possible to gel it in a few seconds to about 10 seconds, and even if it exceeds 5% by weight, the rapid setting effect will not increase, and the kneading of liquid B will be worse. This is because stability deteriorates.

Furthermore, the reason for specifying aluminum sulfate in the present invention is that known cement quick setting agents made of inorganic chlorides such as calcium chloride and iron chloride require gelling time of 10
This is because it cannot be shortened to about seconds.

As a device for mixing both A and B, use a Y-shaped tube with a short merging section after merging the A and B liquids, or a double tube, with one liquid in the inner tube and the other. A double pipe construction method in which the liquid is injected into the gap between the inner pipe and the outer pipe and merged at the tip of the double pipe or in the air flowing out from the double pipe, and 2
A method such as arranging two pipes so that they are close to each other and can quickly merge in the air can be used.

According to the method of the present invention, when both liquids A and B are mixed, they gel in a few seconds to about 10 seconds, and the short-term strength (compression) is increased by 20 to 30% compared to when aluminum sulfate is not added. It is useful for large water stops, production of secondary concrete products, spraying construction methods, seabed sludge treatment, etc.

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

Example: Cement rapid hardening material consisting of a mixture of equal weights of amorphous 12Ca0/7A1203 and anhydrite, a setting retarder consisting of a mixture of potassium carbonate and citric acid with a weight ratio of 32''1, and water in various proportions. Solution A was prepared by mixing, while solution B was prepared using ordinary Portland cement, aluminum sulfate, and water, and the gelation time after mixing both solutions A and B was measured.

The results and the blending conditions for both solutions A and B are shown in Table 1.

Experiments/I61 and 4 are formulations different from the present invention.

The amount of the setting retarder is expressed as % by weight based on the cement rapid hardening material, and the amount of aluminum sulfate is expressed as 4% by weight based on the cement.

Claims (1)

[Claims] 1 Prepare a slurry containing calcium aluminate and inorganic sulfate as an active ingredient as a quick-hardening cement as liquid A, and prepare a slurry containing cement as an active ingredient as liquid B separately, and combine both liquids during construction. In the method of hardening cement, B liquid contains 0.5 to 5
A method for rapid hardening of cement, characterized by the presence of % by weight of aluminum sulfate.