JPH0415273B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a grout injection method for filling a gap between a foundation rock of a structure or a concrete structure and the ground.

<Prior Art> When injecting a grout injection material, it is desirable to accurately obtain the time for the injection material to harden, that is, the gel time.

Therefore, the current injection method for cement-based ultra-fast hardening injection materials is as follows.

First, liquid B is prepared by adding gypsum and a setting retardant such as bicarbonate or carbonate to a rapid setting agent mainly composed of calcium or aluminate minerals.

Next, before pouring into the ground, liquid B and cement (liquid A) are stirred or mixed.

After that, it is injected into the ground to generate Etrin guide (calcium, sulfur aluminate) and cause it to set quickly.

<Problems to be Solved by the Invention> The conventional grout injection techniques described above have the following problems.

Calcium and aluminate quick-setting agent of B liquid are:
They contain calcium salts and are easily ionized.

Therefore, before injecting into the ground, stir the B liquid.
If kneaded (mixing, agitating), the calcium salt and the setting retarder will react and the amount of the setting retarder will decrease.

As a result, when mixing the two liquids A and B, the amount of retardant as originally planned cannot be secured, so the gel time varies depending on the kneading time.

However, calcium and aluminate-based quick-setting agents use melted products produced by melting calcium-based minerals and aluminum-based minerals, so it is impossible to separate them into calcium salts and other substances. , is impossible.

Therefore, until now, fluctuations in gel time have been unavoidable in cement-based ultra-fast hardening injection materials.

<Object of the present invention> In order to solve the above-mentioned problems, the present invention has the following objectives:
The purpose is to provide a grouting method as follows.

Preventing the reduction of the setting retarder due to the reaction between the calcium salt contained in the B liquid side and the setting retarder,
A grout injection method that allows grout to be injected into the ground with almost no change in gel time.

<Configuration of the Present Invention> An embodiment of the present invention will be described below with reference to the drawings.

(a) Composition of liquid A Liquid A consists of a mixture of materials whose main constituents are calcium salts, such as cement, lime, and gypsum.

(b) Composition of B liquid B liquid consists of an activated alumina salt quick setting agent and a setting retarder.

(1) Activated alumina salt-based quick-setting agent This agent is used to mix materials with extremely high water content such as injection materials (generally W/C≧100%, W = water, C = solid content such as cement, quick-setting materials, etc.). In order to achieve gelation within a few minutes, when cement is used as the main ingredient, ettringite (3CaO,
It is necessary to make Al ₂ O ₃・3CaSO ₄ , nH ₂ O).

To make this ettringite, calcium aluminate and gypsum, or slaked lime, or gypsum and activated alumina salts are required.

In the present invention, in order to prevent the calcium salt contained in the accelerating agent from reacting with the setting retarder over kneading time, reducing the amount of the setting retarder and affecting the gel time, the calcium salt and the setting retarder are Activated alumina salt is used for the purpose of dispersing the alumina salt.

As the activated alumina salt quick-setting agent, for example, calcined soybean, alcite (amorphous alumina), a mixture thereof, or a mixture thereof with a trace amount of potassium soybean or sodium aluminate added thereto can be used. .

As an example, the components of calcined soybean paste and alcite (amorphous alumina) are shown in the table of FIG.

Calcined soybean is made by firing Kari soybean at 650℃ and is given by the following chemical formula.

Kari miyouban Temporarily baked miyouban K ₂ O・3Al ₂ O ₃・4SO ₃・6H ₂ O→Al ₂ (SO ₄ ) ₃ K ₂
SO ₄ +2Al ₂ O ₃ +H ₂ O 650℃ (amorphous) The calcined sour bean shown in Fig. 1 is made by baking alum stone at 500℃, and is different from the calcined sour bean in the above formula. Although their compositions are different, their chemical reaction power is almost the same.

(2) Setting retarder Examples of setting retarders include soda carbonate,
Calcium salt, a mixture of potassium carbonate, bicarbonate of soda, and 2 kettle gluconic acid, citric acid, etc.
Use one that does not contain divalent metal salts such as magnesium salts.

Calculated soybean paste and alcite contain very little calcium salt and magnesium salt, so even if the retarder is mixed and stirred, the gel time is hardly affected.

(c) Other Examples (1) When active silica powder such as ultrafine silica hume with extremely high silica purity is added to liquid B, the gelation properties are improved (gel A sharp increase in viscosity is observed from the start of the reaction to the solidification reaction.

Further, even if these are added, since they do not contain divalent metal salts, they have almost no effect on the variation in gelation time due to kneading time.

(2) When the pH of the material on the B liquid side is almost neutral,
By adding pozzolanic materials such as blast furnace slag and fly ash to the B liquid side, the viscosity of both liquids can be adjusted.
It is possible to measure the long-term stability improvement after solidification.

That is, for example, blast furnace slag contains calcium salts, and is self-hardening in an alkaline solution, and ionization of the calcium salts is intense, but it is slow in the neutral range.

Therefore, if blast furnace slag is added to the B liquid side, there will be some variation in the gel time, but in cases where some variation in the gel time is acceptable due to the slow reaction rate of the color, adding blast furnace slag to the B liquid side is recommended. be able to.

In addition, when the W/C is large, the 1-4 week strength can be significantly improved by adding blast furnace slag, so it has important significance in applications where some variation in gel time is acceptable.

(e) Comparative example (1) Prior art Liquid A is a slurry made by mixing and stirring 300 g of Portland cement and 400 c.c. of water, and a slurry in which calcium, 75 g of an aluminum silicate quick-setting agent, and 475 c.c. of water are mixed. is called liquid B.

Then, on the B liquid side, potassium carbonate and citric acid retardant.
1.25g or 1g of added material for each solution
Knead for ~60 minutes, mixing both solutions A and B every hour.
Gelation time was measured using a rotational viscometer.

In FIG. 2, the horizontal axis shows the kneading time, and the vertical axis shows the gelation time, and the mark "*" shows the case where the retarder is 1.25 g, and the "X" shows the case where the retarder is 1 g.

From this figure, it can be seen that for each retarder amount, as the kneading time becomes longer, the gelation time becomes shorter.

From this, it can be seen that the calcium and aluminate-based quick-setting agent and the retarder gradually react, and the gelation time is affected not only by the retarder material but also by the kneading time.

(2) Technology of the present invention Portland 246g, slaked lime 21.4g, anhydrite
Mix and stir 49.2g of 49.2g of water and 393.4g of water to make the slurry A liquid, add 18.5g of calcined soybean paste, 18.5g of alcite mixed quick setting agent, 44.5g of 2-ketogluconic acid and potassium carbonate mixed retardant, and 476.3g of water. The mixed and stirred slurry is referred to as liquid B.

Each liquid was kneaded for 10 to 80 minutes, and both liquids A and B were mixed at each time interval, and the gelation time was measured using a rotational viscometer.

FIG. 3 shows an hourly viscosity curve record of a rotational viscometer superimposed for each hour.

The vertical axis of this figure represents the viscosity η, and the unit is C·
P (centipoise).

Moreover, the horizontal axis indicates the elapsed time from mixing.

From this figure, gelation begins 3 minutes after mixing for slurries with any mixing time, and gelation occurs with rapid setting agents and retarders that do not contain divalent metal salts such as calcium salts and magnesium salts depending on the mixing time. This shows that the effect of valence time is very small.

The present invention discovered this phenomenon and applied it to the injection method.

<Effects of the Present Invention> Since the present invention has been described above, the following effects can be expected.

Setting Retarder When a calcium aluminate-based quick setting agent is kneaded, the setting retarder reacts with the calcium salt contained in the quick setting agent depending on the kneading time, reducing the setting retarder and increasing the gel time. Give variation.

However, by using an activated alumina salt-based quick-setting agent that does not contain calcium salts, the above-mentioned fluctuations in gel time can be prevented.

Therefore, since it is possible to create an accurate gel time when injecting the grouting material into the ground, a better grout injection method has become possible.

[Brief explanation of drawings]

Figure 1: Table of ingredients for calcined soybean paste and alcite, Figure 2: Gel time change table of conventional technology, Figure 3
Figure: Gel time change table of the present invention.

Claims (1)

[Claims] 1. In the AB2 liquid mixing injection method that adjusts the gel time by producing an Etrin guide, reactive 2 consisting of cement, slaked lime or gypsum.
Liquid A is mainly composed of a valent metal salt, and Liquid B is made of an active alumina salt quick setting agent that does not contain divalent metal salts such as Ca or Mg, and a setting retarder of potassium carbonate or sodium carbonate organic acid salt. A grout injection method characterized by: 2. The grout injection method according to claim 1, characterized in that activated silica consisting of silica hume is further added to the B solution. 3. The grout injection method according to claim 1, characterized in that a bozolan material made of blast furnace slag or fly ash is added to the B liquid when the B liquid is substantially neutral.