JPS5964551A - Cement composition - 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 an early-strengthening cement composition, particularly an early-strengthening cement composition suitable for effective use in cement injection into the ground.

It is widely known that quick-setting cement is used to fill joints to stop water from flowing out of gaps and cracks in the ground or bedrock.

In other words, these grout materials are used to stop water by adding an appropriate amount of water at the leak site and immediately before the grout solidifies and solidifies into the leak area, and many types of compositions have been used so far. It has been proposed. For example, these typical quartz cements include portland cement mixed with alumina cement, but each has its advantages and disadvantages.

The present invention relates to the improvement of this type of Portland cement and alumina cement system, and meets the requirements of early strength, improved long-term strength, good workability, and as little breathing phenomenon as possible, which are particularly necessary for grouting. We have succeeded in providing something that combines the following.

That is, the present invention uses portland cement, alumina cement, slaked lime, alkali metal carbonate, and carboxylic acid (salt).
The gist of the invention is a cement composition containing each of these in specific proportions.

The components constituting the composition of the present invention, their ratios (weight t% or less) and preferred ranges are as follows.

Scope of the present invention Preferred range Particularly desirable range Portland cement 70-30 65-35 4
5~35 Alumina cement 5~50 15~
50 30-50 Slaked lime 3-30
7-2513-25 First of all, alumina cement is mainly composed of calcium aluminate, and C
Including aO-At203, 12C! a○7A4
z○3゜5CaO-At203. 110a07At2
03・OaF, 4CaO・At203・Fe2O2
It may also be a mixture containing components such as. This alumina cement usually has a Blaine value of 5.000 to 5.000 c
m"/f is sufficient, but for those used for special purposes, for example, if you want to further improve properties such as breathing, sinking rate (settling of solid content), and rapid hardening, IQ, 000 tyn2 It is effective to use /f or higher.

The blending ratio of alumina cement is based on the total amount of each calcium aluminate component as described above, and if the ratio exceeds 50%, alumina cement hydrate will form when mixed with water. If it is less than 5 inches, the early strength as a grout material cannot be obtained, so it must be limited as mentioned above.

Portland cement has calcium silicate as its main component, and it is possible to use not only ordinary Portland cement but also early-strength cement and ultra-early-strength cement, which have become widely used as improvements in recent years.

The mixing ratio of this portland cement is limited as mentioned above because if it is too large, the early strength as a grout material will be poor, and if it is too small, the increase in strength that should appear as the age of the material after construction increases will be small. be done.

Slaked lime must be used as Ca(OH)z, and its purpose cannot be fully achieved if it is used as limestone (0aOO3) or quicklime (OaO). If the amount used as 0a(OH)2 is too large, both the initial and long-term strength will not be sufficient, while if it is too small, the early strength will not be sufficient, so there is a limit as described above.

Alkali metal carbonate is Na2003 + NaH
2 C to O03*! 03, KHC! Among them, sodium carbonate (Na2003) can be used.
is the best. The amount used is limited to the above-mentioned range because if it is too small, it will not be possible to obtain early strength properties, and if it is too large, the early strength properties will be poor.

Organic carboxylic acids or salts thereof such as citric acid, tartaric acid, gluconic acid, and malic acid can be used as the carboxylic acid or a salt thereof, and among them, citric acid or a salt thereof is most suitable.

If the amount used is too large, the strength will increase, but the breathing property will be severe and it is not practical. On the other hand, if it is too small, the fluidity will be poor in the above four-component system and construction will be difficult. It is limited to the above-mentioned range because it also reduces the amount by half.

The present invention is a composition containing each of these five components in specific amounts, and when used as a grout material, approximately 50 to 3
00 parts In many cases, it is made into a slurry with about 100 to 200 parts of water, and once it has a suitable fluidity, it is press-fitted into the target injection site such as the ground.

When preparing such a slurry, it is of course possible to use appropriate thickeners, swelling agents, foaming agents, etc. for various purposes, such as reducing pleating properties and sinking rates, depending on the respective purpose. However, it is also possible to add other powder raw materials to the extent that the object of the present invention is not impaired.

As described above, the present invention can ensure appropriate workability required as a grout material, has little tendency to precipitate after mixing with water, and has almost no settling of the slurry after construction. It provides excellent performance in terms of long-term strength, and has great industrial value as a material used for emergency construction and applications such as grouting where a gradient in the number of construction days is required.

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

Examples and Comparative Examples Portland cement (manufactured by Mitsubishi Mining Cement Co., Ltd.,
Blaine value: 3100 cm27t), alumina (Asahi Fuonsh, produced by Asahi Glass Co., Ltd., Blaine value: 5300 cm2/litre), slaked lime (purity 96%), sodium carbonate (purity 99.9%) and citric acid. 1st
The mixtures were prepared according to the proportions (wt%) shown in the table, and after thorough mixing, water was added in an amount such that the water/solids ratio was 150% based on the solids.

The results of measuring the gelation time (minutes), consistency (seconds), pleating rate (%, after 3 hours of cross-contact), settling rate (1 day old), and compressive strength (K17cm2) for these were also shown in the first table. Shown in the table.

The method for measuring the results is as follows.

・Geling time: Approximately 8 times the contaminant in a 100CC beaker
The time required until the contents no longer flow out even when the container was tilted by 90 degrees was determined after 0 cc was poured into the container and allowed to stand still.

・Consistency; ASTM C! The method of 939-81 was adopted.

・Pleading rate; It was measured by a method similar to J Engineering 8 A 1123.

・Sinking rate; diameter 56n depth 10c! A crosstalk material was placed in a cylinder of No. n, and after one day, the length was measured from the top of the container to the top surface of the cured sample.

Table 1 Practical Examples Examples Comparative Examples Comparative Examples Comparative Examples Comparative Examples
□(II (21(31f4! I!51
(61 (7) Portland cement 40 55 -55 4
0 40 55 90 Alumina cement
40 25 35 40 40 5
H) Oa(OH)2 20 20
10 20 20 40 1ONa2
CO322,550223 Citric acid 0.2 Q,2 0.15 0
0 0.2 Q, 15 water/solids ratio 150 1
50 1'50 150 150 150 150 Gelation time 10 14 12 2 0 5
5 14' Consistency 7.5
Zo Zo 9 oO7,48 praising rate 0.1 0. j O, 1500254,
5Sinking rate 0.10 0.2 0.15 0
0 30 5 Compressive strength after 5 hours ELl 5,2 6.7 [1,82
-0' 0 0.051 days later 15.8 1
3.0 14.5 1.0 5. 'OO,3,g,
428 days later 25,0 20.6 '1a5
4.0 10.5! L5 15,1 As can be seen from these results, the composition according to the present invention
1f2) As shown in (3), the gelling time is approximately 5 to 15 minutes, which is the minimum and appropriate time necessary for the work, and the gelation time is 7 to 8 minutes, which is sufficient for practical use. Cystin Sea, has excellent performance with a breathing rate and sinking rate of less than 0.2%.

In addition, it has an early strength that shows a strength of 5 kg 7 cm or more after 3 hours, and a strength of 20 Ky/28 days after 28 days.
It has excellent performance with a value of σ2 or more.

On the other hand, in Comparative Examples 4 and 5, since no alkali metal carbonate or carboxylic acid, which is essential in the present invention, was added, the gelation time was too fast and the fluidity was poor. Both the hourly intensity and the 28-day intensity are low. Comparative Example (6) Tel is an example in which too much slaked lime and Portland cement were used. There are many practical problems, such as the gelation time being too long, the bleeding rate and settling rate being too high, and the early strength being poor.

336

Claims (1)

[Claims] 1. Portland cement 70 to 60 inches by weight;
A cement composition comprising 5 to 50% alumina cement, 5 to 30 g of slaked lime, 5 to 5 percent of alkali metal carbonate α, and 0.05 to 1 g of carboxylic acid or its salt. 2. Portland cement 65-35%, alumina 15-50%, slaked lime 7-25%, alkali metal carbonate 0.7-3.0% and carboxylic acid 0.1-0.
3. The cement composition according to claim 1, which is 3 yen. & The cement according to claim 1 or 2, which contains 45-65% bolt cement, 30-50% alumina cement, 13-25% slaked lime, and 1-2-5% alkali metal carbonate. Composition. 4. The cement composition according to any one of claims 1 to 5, wherein the alkali metal carbonate is sodium carbonate. 5. The cement composition according to any one of claims 1 to 4, wherein the carboxylic acid or its salt is citric acid or its salt. & The cement composition according to any one of claims 1 to 5, wherein the composition is used for grout.