JP2003165758A - Back-filling grout - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a back-filling grout mainly used in constructions, which is environmentally pollution-free in case that an underground water or a leak of water is present since an elution of a hexavalent chromium ion from the grout is remarkably little even in a unhardened state. <P>SOLUTION: The back-filling grout contains a slowly cooled blast-furnace slag powder whose sulfur content as a non-sulfate form is ≥0.5% and glass content is ≤30%. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention mainly relates to a backfill injection material used in the civil engineering and construction industry. In addition,
Parts and% in the present invention are based on mass unless otherwise specified.

[0002]

2. Description of the Related Art From the viewpoint of environmental problems, environmental standards have been established for hexavalent chromium that adversely affects the human body (Environmental Agency Notification No. 46, etc.). On the other hand, the cement-based material contains a small amount of chromium, and due to the increased frequency of waste treatment in cement production, cement with a relatively high chromium content is rarely found. In addition, the amount of hexavalent chromium eluted varies greatly depending on how the cement-based material is used. Although hexavalent chromium in an amount exceeding the environmental standard (0.05 mg / l) does not elute from ordinary cement hardened products, for example, when used with a high water cement ratio such as backfilling injection of tunnel, There is concern that hexavalent chromium may exceed the environmental standards and may be eluted. In addition, if there is a water vein in the natural ground or if there is a water leak, a part of it will be washed away before the backfill injection material solidifies, and it may be a condition that makes it easier to elute hexavalent chromium. is expected.
However, the fact is that no radical measures have been taken regarding the elution of hexavalent chromium in backfill injection applications.

A method of reducing the amount of hexavalent chromium eluted by using a reducing agent, an adsorbent or the like has been proposed. However, these reducing agents and adsorbents are too expensive to be used in the cement / concrete field, and are rarely used.

Among blast furnace slags, granulated blast furnace slag powder obtained by pulverizing granulated blast furnace slag is also known to act as a reducing agent for hexavalent chromium.

The present inventor has earnestly made efforts and has completed the present invention by finding that the above problems can be solved by using a specific backfill injection material.

[0006]

Means for Solving the Problems That is, the present invention is a backfill injection material containing blast furnace slowly cooled slag powder, wherein the content of non-sulfuric acid sulfur in the blast furnace slowly cooled slag powder is 0.5% or more. The backfill injection material is a backfill injection material in which the vitrification rate of the slowly cooled blast furnace slag is 30% or less.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below.

The blast furnace slowly cooled slag powder (hereinafter referred to as slowly cooled slag powder) used in the present invention is a powder of blast furnace slag that is slowly cooled and crystallized. The components of the slowly cooled slag powder have the same composition as granulated blast furnace slag, and specifically, SiO ₂ , Ca
O, Al ₂ O ₃ and MgO are the main chemical components, and other components are TiO ₂ , MnO, Na ₂ O, S, P ₂ O ₅ and Fe ₂ O ₃
And so on. The compound is a mixed crystal of gehlenite _{2CaO · Al 2 O 3 · SiO} 2 and Akerumanaito 2CaO · MgO · 2SiO _2, a so-called melilite as the main component, other, dicalcium silicate 2CaO · SiO _2, rankinite night 3CaO・ 2SiO ₂ , and calcium silicates such as wollastonite CaO ・ SiO ₂ , calcium magnesium silicates such as merbinite 3CaO ・ MgO ・ 2SiO ₂ and monticellite CaO ・ MgO ・ SiO ₂ , anorthite CaO ・ Al ₂ O ₃・ 2SiO ₂ , Leucite (K ₂ O, Na ₂ O) ・ Al ₂ O ₃・ SiO ₂ , spinel MgO ・ Al ₂ O ₃ , magnetite Fe ₃ O ₄ , and calcium sulfide CaS and iron sulfide
May contain sulfides such as FeS. These sulfides are exposed on the surface of the particles by pulverizing the slowly cooled slag, and when contacted with water, they are eluted as thiosulfate ions or sulfite ions and exhibit hexavalent chromium reducing performance.

In the present invention, among the slowly cooled slag powder, for example, sulfur existing as non-sulfate sulfur such as sulfide, polysulfide, sulfur, thiosulfuric acid, and sulfurous acid (hereinafter, simply referred to as non-sulfate sulfur). The gradual cooling slag powder that is powdered containing 0.5% or more is used. Non-sulfate sulfur is 0.
If it is less than 5%, the effect of the present invention, that is, the reducing performance of hexavalent chromium may not be sufficiently obtained. The non-sulfate sulfur is 0.5% or more, preferably 0.7% or more, and more preferably 0.9% or more. The amount of non-sulfate sulfur is the total amount of sulfur,
By determining the amount of elemental sulfur, the amount of sulfide-type sulfur, the amount of thiosulfate-sulfur, and the amount of sulfate-sulfur (sulfur trioxide) by the method of Yamaguchi and Ono, and the amount of sulfate-sulfur (sulfur trioxide) And the amount of sulfide-type sulfur, JI
Obtained by quantifying according to the method specified in SR 5202 (see "Analysis of Sulfur State in Blast Furnace Slag", Naoji Yamaguchi, Akihiro Ono, Iron Making Research, No. 301, pp.37-40, 1980).

The vitrification rate of the slowly cooled slag powder used in the present invention is preferably 30% or less, more preferably 10% or less. When the vitrification ratio exceeds 30%, the effect of the present invention, that is, the hexavalent chromium reducing performance may not be sufficiently obtained. When the vitrification rate is high, even if it contains almost the same amount of non-sulfuric acid sulfur, the slag powder with a high vitrification rate is less leaching of thiosulfate ions, etc.
The reduction performance of valent chromium is small. Vitrification rate in the present invention
(X) is calculated as X (%) = (1−S / S ₀ ) × 100. Here, S is melilite (gerenite 2CaO ・ Al ₂ O ₃・ SiO ₂ and akermanite 2CaO ・ MgO ・), which are the main crystalline compounds in the slowly cooled slag powder obtained by the powder X-ray diffraction method.
₂ SiO ₂ mixed crystal) is the main peak area, and S ₀ is the area of the main peak of melilite, which was obtained by heating the slowly cooled slag powder at 1,000 ° C. for 3 hours and then cooling it at a cooling rate of 5 ° C./min. Represent

The fineness of the slowly cooled slag powder is not particularly limited, but it is preferable that the Blaine specific surface area (hereinafter referred to as Blaine value) is 4,000 cm ² / g or more, and 4,500 to 8,000 cm ²
/ g is more preferable, and 5,000 to 8,000 cm ² / g is most preferable. When the Blaine value is less than 4,000 cm ² / g, the effect of the present invention,
That is, the reduction performance of hexavalent chromium may not be sufficiently obtained. Also, to grind to over 8,000 cm ² / g,
The pulverization power becomes large, which is uneconomical, and the slow-cooled slag powder is likely to be weathered, and the deterioration of quality over time may become large. By this fineness, it is possible to control the elution amount of thiosulfate ion, sulfite ion, etc. By increasing the fineness, the initial hexavalent chromium reduction performance is improved, and conversely, by lowering the fineness, long-term It is possible to provide a hexavalent chromium reducing performance over the range.

The amount of the slowly cooled slag powder is not particularly limited, but usually 5 to 100 parts is preferable, and 10 to 50 parts is more preferable, relative to 100 parts of cement in the backfill injection material. If it is less than 5 parts, the effect of the present invention may not be sufficiently obtained, and if it is used in excess of 100 parts, strength development may be deteriorated.

The backfill injection material according to the present invention (hereinafter referred to as the present injection material) is not particularly limited, but it is usually a general backfill injection material roughly classified into air mortar type and cement bentonite type. It contains slowly cooled slag powder. The air mortar-based backfill injection material is a mortar in which the amount of air is significantly increased by using a foaming agent, etc.
It is in the range of ~ 2.0. In addition, the cement bentonite-based backfill injection material is characterized in that it contains cement, bentonite, and water as main components and contains a large amount of water.

As the cement used in the present invention, various portland cements such as normal, early strength, ultra-early strength, low heat, and moderate heat, and various mixtures of these portland cements with blast furnace slag, fly ash, or silica are mixed. Filler cement mixed with cement, limestone powder, etc.,
In addition, waste-using cement, so-called eco-cement, and the like can be mentioned, and one or more of these can be used.

In the present invention, in addition to the slowly cooled slag powder, conventionally known harmful substance reducing agents can be used in combination within a range not substantially impairing the object of the present invention. Specific examples thereof include, for example, layered compounds represented by montmorillonite and kaolinite, so-called bentonites, zeolites represented by clinoptilolite and mordenite, sepiolite, apatite, phosphoric acid such as zirconium phosphate. Salt, antimonic acid salts such as antimony trioxide and antimony pentoxide, hydrotalcites, activated carbon, polysulfides, sulfides, thiosulfates, and sulfur compounds such as sulfites, amalgam, ferrous sulfate,
And iron compounds such as ferrous chloride, water-soluble polymers such as celluloses, polyvinyl alcohol, and chitosan, dialkyldithiocarbamic acids, quinoline compounds, polyamines, and sugars, and one of these. Alternatively, two or more kinds can be used in combination.

Further, in the present invention, in addition to aggregates such as cement, bentonite, slowly cooled slag powder, and sand, granulated blast furnace slag powder, limestone powder, fly ash, and admixtures such as silica fume, inorganic materials and / or Or organic plasticizers, inorganic sulfates, foaming agents, defoamers, thickeners, water reducing agents, A
E water reducer, high performance water reducer, high performance AE water reducer, antifreeze,
One or more of shrinkage-reducing agents, polymer emulsions, rapid hardening materials, expanding materials, and setting regulators such as setting accelerators and setting retarders do not substantially impede the object of the present invention. It can be used in a range.

In the present invention, the method of mixing the respective materials is not particularly limited, and the respective materials may be mixed at the time of construction, or part or all of them may be mixed in advance. . As the mixing device, any existing device can be used, and for example, a tilting barrel mixer, an omni mixer, a Henschel mixer, a V-type mixer, and a Nauta mixer can be used.

[0018]

The present invention will be further described below based on experimental examples.

Experimental Example 1 Using the backfilling injection material b, 10 parts of each slowly cooled slag powder (slag) shown in Table 1 was used with respect to 100 parts of the cement, and the elution amount of hexavalent chromium was confirmed. However, slag was used by replacing it with fine aggregate. The results are also shown in Table 1.

<Materials used> Cement: ordinary Portland cement, manufactured by Denki Kagaku Kogyo Co., Ltd., specific gravity 3.15 Slag A: slowly cooled slag powder, Blaine value 4,000 cm ² / g, vitrification rate 5%, specific gravity 3.00, non-sulfuric acid sulfur 0.9% Slag B: Gradually cooled slag powder, Blaine value 4,500 cm ² / g, vitrification rate 5%, specific gravity 3.00, non-sulfate 0.9% Slag C: Gradually cooled slag powder, Blaine value 5,000 cm ² / g, glass 5%, specific gravity 3.00, non-sulfuric acid sulfur 0.9% Slag D: slowly cooled slag powder, Blaine value 6,000 cm ² / g, vitrification rate 5%, specific gravity 3.00, non-sulfuric acid sulfur 0.9% slag E: slow cooling Slag powder, Blaine value 8,000 cm ² / g, vitrification rate 5%, specific gravity 3.00, non-sulfuric acid sulfur 0.9% Slag F: slowly cooled slag powder, slag d is immersed in water for aging to produce non-sulfuric acid sulfur 0.7%, Blaine value 6,000 cm ² / g, Vitrification rate 5%, Specific gravity 3.00 slurry G G: Gradually cooled slag powder, slag d immersed in water and aged to make non-sulfate sulfur 0.5%, Blaine value 6,000 cm ² / g, vitrification rate 5%, specific gravity 3.00 Slag H: Gradually Cold slag powder, Blaine value 6,000 cm ² / g, vitrification rate 10%, specific gravity 2.97, non-sulfuric acid sulfur 0.7% Slag I: Gradually cooled slag powder, Blaine value 6,000 cm ² / g, vitrification rate 30%, specific gravity 2.94, non-sulfate 0.5% Slag J: Granulated blast furnace slag powder, Blaine specific surface area 6,00
0 cm ² / g, vitrification rate 95%, specific gravity 2.90, non-sulfate sulfur 0.
6% backfill injection material a: Air mortar type backfill injection material, commercial product, cement 300 kg / m ³ , fine sand 600 kg / m ³ , water 230 kg / m ³ ,
20-fold diluted foaming agent 16 kg / m ³ , plasticizer 30 kg / m ³ , air content 40% Cement: Commercially available ordinary Portland cement Equal volume mixture of 3 brands, specific gravity 3.15 Water: Tap water fine aggregate: Fine SunaOkoshi foams: manufactured by Sumitomo Osaka Cement Co., Ltd., trade name "Sumi shield", without chromium-containing plasticizing agent a: commercially available, as a main component as Al ₂ O ₃ and SO _3, without chromium

<Measurement Method> Hexavalent Chromium Elution Amount: The state in which the hexavalent chromium was not solidified immediately after kneading and the hardened body after solidification were measured according to the method described in Environmental Agency Notification No. 46. However, the amount of hexavalent chromium that has not solidified immediately after kneading can be determined by collecting 50 g of a kneaded product of various backfill injection materials and adding pure water 500
cc was added and shaken, and after 6 hours, solid-liquid separation was performed, and the concentration of hexavalent chromium in the liquid phase was measured.

[0022]

[Table 1]

Experimental Example 2 The procedure of Experimental Example 1 was repeated except that Slag D shown in Table 2 was used. The results are also shown in Table 2.

[0024]

[Table 2]

Experimental Example 3 Table 3 was used for 100 parts of cement by using the backfill injection material b.
The same procedure as in Experimental Example 1 was carried out except that Slag D was used in the ratio shown in. The results are also shown in Table 3. However,
The slag was replaced with bentonite before use. For comparison, the measurement results of backfill material A are also shown.

<Materials used> Back-filling injection material B: Cement bentonite-based back-filling injection material, cement 300 kg / m ³ , bentonite 300 kg / m ³ , water 782 k
g / m ³ , and plasticizer a ³ kg / m ³ plasticizer b: commercial product, main component acrylic emulsion,
Does not contain chromium.

[0027]

[Table 3]

[0028]

INDUSTRIAL APPLICABILITY The backfilling injection material of the present invention has a significantly small amount of hexavalent chromium eluted, and in particular, the amount of hexavalent chromium eluted is small even in the state where it is not yet solidified. Even if there is water leakage, the environment is not polluted.

Claims (3)

[Claims] 1. A backfill injection material containing blast furnace slowly cooled slag powder. 2. The backfill injection material according to claim 1, wherein the content of non-sulfuric acid sulfur in the slowly cooled blast furnace slag powder is 0.5% or more. 3. The vitrification rate of the slowly cooled blast furnace slag powder is 30%.
The backfill injection material according to claim 1 or 2, wherein: