JPH11263972A - Grouting material for improving ground - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject grouting material capable of promoting the setting and hardening of a cement, facilitating the regulation of the gelation time, increasing the strength of a consolidated material and effectively utilizing wastes by mixing a specific rapid hardening baked material with a gypsum and an alkali carbonate in a specific proportion. SOLUTION: This grouting material contains (A) a rapid hardening baked material obtained by using a municipal refuse incinerated ash or a sewage sludge incinerated ash as a raw material [e.g. a material containing 10-40 wt.% of an aluminum compound which is C11 A7 CaCl2 , C11 A7 CaF2 or C3 A and a compound which is C2 S or C3 S prepared by baking a sewage sludge dried powder obtained by mixing shells or a sewage sludge with quick lime at 1,200-1,500 deg.C temperature and pulverizing the resultant clinker], (B) a gypsum in an amount of 5-50 pts.wt. based on 100 pts.wt. of the rapid hardening baked material, (C) an alkali carbonate in an amount of 0.5-30 pts.wt. based on 100 pts.wt. of the rapid hardening baked material A and, as necessary, further (D) a setting retarder (e.g. citric acid) in an amount of <=5 pts.wt. based on 100 pts.wt. of the rapid hardening baked material A.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a gel time (a gelation time of a mixed slurry of an injection material for soil improvement and cement) used in combination with cement for strengthening soil, stopping water, and backfilling tunnels, segments, and the like. )
The present invention also relates to a ground improvement injection material capable of arbitrarily adjusting the strength of a consolidated body.

[0002]

2. Description of the Related Art Conventionally, main materials used for a ground improvement injection material are roughly classified into a water glass type, a polymer type and a cement type.

[0003] Water glass-based materials are composed of a combination of a reaction material such as sodium bicarbonate or sodium chloride and water glass, and adjust the gel time and strength by changing the concentration of water glass and the mixing ratio of both.

[0004] The high molecular material includes acrylamide, urea formalin condensate, urethane and the like, and high strength can be obtained in a short time by polymerizing by adding a catalyst.

[0005] Cement-based materials consist of a combination of a cement rapidly hardened material such as molten calcium aluminate and cement, and the gel time and strength are adjusted by changing the concentration and blending ratio of both.

[0006] However, it is known that the strength of the water glass-based compact decreases with time, and furthermore, there is a problem of environmental pollution due to elution of alkali. Also,
Because of high toxicity of polymer materials, they are rarely used except in cases where urgency is required. Further, although the cement-based material has almost no toxicity and is excellent in the durability of the consolidated body, the strength of the consolidated body is not sufficiently developed.

On the other hand, in recent years, general waste such as municipal waste and sewage sludge and industrial waste have increased remarkably, and effective use and recycling of waste have been attempted in various fields. There is no traditional method, and at present, it depends on landfill. However, recently, in the field of cement production, for the purpose of effective use and recycling of wastes, wastes such as municipal waste incineration ash and sewage sludge incineration ash have been used as raw materials for rapidly burning hydrated products (hereinafter, referred to as "fired materials"). (Referred to as a rapidly hardened product).

[0008]

SUMMARY OF THE INVENTION Accordingly, the present invention provides an injectable material for soil improvement that promotes the setting and hardening of cement, facilitates adjustment of gel time, and has high initial and long-term strength development of a consolidated body. The purpose is to provide. Another object of the present invention is to achieve effective use and recycling of waste through the use of a rapidly hardened product produced from waste.

[0009]

The inventors of the present invention have conducted intensive studies on the reaction of accelerated hardening of cement by a rapidly hardened material, and as a result, a certain mixture of a rapidly hardened material, gypsum and an alkali carbonate has been obtained. Further, the present inventors have found that when a setting retarder is added to this mixture, the pot life of the ground injection material and the gel time of the mixed slurry of the ground injection material and cement can be easily adjusted, and the present invention has been completed. That is, the present invention relates to (1) 5 to 50 parts by weight of gypsum and 0.5 parts by weight of alkali carbonate with respect to 100 parts by weight of a rapidly hardened fired product.
Provided is an injection material for soil improvement containing up to 30 parts by weight.
Also, (2) the ground improvement injection material may further contain 5 parts by weight or less of a setting retarder, and (3) such a rapidly hardened fired product is C ₁₁ A ₇ CaCl ₂ , C ₁₁ A ₇ CaF 2. _2, there is provided a C ₃ 10 to 40% by weight of one or more of a and C ₂ S, soil improvement for injection material is a fired product comprising one or more C ₃ S.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION
It is a baked product produced using at least one of municipal garbage incineration ash and sewage sludge incineration ash, and furthermore, C ₁₁ A ₇ CaC
is _{l 2, C 11 A 7 CaF} 2, C 3 baked product comprising at least one of 10 to 40 wt% and C ₂ S, C ₃ S 1 or more of the A. The raw materials used here are sewage sludge dry powder obtained by mixing quicklime with shells and sewage sludge, other general waste and industrial waste, and limestone, clay, silica stone, aluminum ash, and bauxite, which are ordinary cement raw materials. It may be a raw material whose components are adjusted by mixing with iron or the like. 1200
The clinker obtained by firing at ~ 1500C is pulverized to produce a rapidly hardened fired product.

Since the aluminum source in such a fired product is mainly derived from incinerated ash, C ₁₁ A ₇ CaCl ₂ , C ₁₁ A ₇ C
If the content of aluminum compounds such as aF ₂ and C ₃ A is less than 10% by weight, the amount of incinerated ash used is reduced, which is not preferable from the viewpoint of effective use of waste and recycling. On the other hand, if it exceeds 40% by weight, it may expand excessively due to the progress of hydration.

As the gypsum used in the present invention, any of anhydrous gypsum, gypsum dihydrate and hemihydrate gypsum can be used, but anhydrous gypsum is preferably used particularly from the viewpoint of initial strength development. Gypsum is preferably added in an amount of 5 to 50 parts by weight based on 100 parts by weight of the calcined product. If the amount is less than 5 parts by weight, the amount of ettringite and monosulfate produced is insufficient, the setting is slow, and the initial strength is reduced. On the other hand, if it exceeds 50 parts by weight, the unreacted gypsum may expand due to hydration, and the long-term strength may decrease.

The alkali carbonate used in the present invention acts on the rapidly hardened calcined product to increase the rate of ettringite formation and increase the initial strength. Examples of the alkali carbonate include sodium carbonate, potassium carbonate, lithium carbonate, and the like, and sodium carbonate is particularly preferable because of being easily dissolved in water. The compounding amount of the alkali carbonate is preferably 0.5 to 30 parts by weight based on 100 parts by weight of the rapidly hardened product. If the amount is less than 0.5 part by weight, the initial strength is not sufficiently increased, and if it exceeds 30 parts by weight, the long-term strength and durability of the consolidated body may be reduced.

The setting retarder used in the present invention has a function of controlling the pot life of the ground improvement injection material of the present invention and the gel time of the mixed slurry. As such a setting retarder, for example, citric acid, gluconic acid, tartaric acid, sucrose and the like can be used, and one or more of these can be used in combination. The addition amount of the setting retarder may be adjusted according to the target pot life or gel time, and is preferably, for example, 5 parts by weight or less based on 100 parts by weight of the rapidly hardened fired product. If used in excess of 5 parts by weight, the strength may decrease. The setting method of the setting retarder may be added in advance to a mixture of other components constituting the ground improvement injection material according to the present invention, but adjustment of the pot life of the ground improvement injection material and the gel time of the mixed slurry. It is preferable to use it after dissolving it in the kneading water of the ground improvement injection material from the viewpoint of easy operation.

Examples of the cement that can be used in combination with the ground improvement injection material of the present invention include ordinary cement, early-strength cement, blast furnace cement, fly ash cement,
Known cements such as fine particle cement and ultra fine particle cement can be used. The use ratio of the ground improvement injection material and the cement of the present invention is not particularly limited, and can be appropriately determined depending on the purpose of use. However, 100 to 1000 parts by weight of cement is preferable with respect to 100 parts by weight of the ground improvement injection material.

Further, since the gel time of the mixed slurry can be arbitrarily adjusted by adjusting the addition amount of the setting retarder, the method for using the injection material for improving the ground of the present invention can be selected in various ways. A one-shot method in which a mixed slurry obtained by simultaneously kneading the ground improvement injection material and cement of the present invention is pumped through one injection pipe and injected into the ground,
(2) Suspensions prepared by separately kneading the injection material for soil improvement of the present invention and cement are separately pumped through two injection pipes, and are joined and mixed immediately before injection into the ground. (3) Suspensions prepared by separately kneading the ground improvement injection material and cement of the present invention are separately pumped through two injection pipes,
Any of the two-shot method of merging and mixing in the ground can be selected according to the gel time.

It is to be noted that the injection material for ground improvement of the present invention and / or
Or a cement, or a kneading water thereof, with a water reducing agent, an AE water reducing agent, a high-performance water reducing agent, a high-performance AE water reducing agent, etc. in order to increase fluidity, and aluminum sulfate, hydroxide, Aluminum, aluminate, alum, calcined alunite, lime, glycerin, triethanolamine, water glass, and the like can also be added.

[0018]

Examples of the present invention will be described below. In addition, these are illustrations and do not limit this invention.

Production Example 1 54.3% by weight of dried municipal incineration ash, 42.5% by weight of limestone powder, 1.1% by weight of aluminum ash, 1.1% by weight of clay, 0.5% of fluorite shown in Table 1 The clinker was calcined at 1300 to 1450 ° C. using a rotary kiln with the weight% as a raw material. The obtained clinker was pulverized by a vertical mill to have a Blaine specific surface area of 4000 cm ² / g to produce a rapidly hardened fired product. Table 2 shows the mineral composition of the manufactured rapidly hardened fired product.

[0020]

[Table 1]

[0021]

[Table 2]

Production Example 2 The rapidly hardened fired product obtained in Production Example 1, anhydrite and sodium carbonate were mixed at the compounding ratio shown in Table 3 to prepare an injection material for ground improvement. The citric acid was used by dissolving it in the kneading water of the ground improvement injection material.

[0023]

[Table 3]

Test Example 1 The injectable material for improvement in each area obtained in Production Example 2 was measured for gel time, initial strength and long-term strength according to the following methods. The work and curing for the following measurements were performed in a constant temperature room at 20 ° C. The results are shown in Table 4.

(Measurement of gel time) 50 g of water was measured into a 300 ml cup, 40 g of ordinary cement was added, and the mixture was kneaded with a mixer for 1 minute (hereinafter referred to as solution B). Also,
In another 300 ml cup, weigh out 60 g of water, dissolve citric acid in water first out of a total of 10 g of each composition shown in Table 3, then add the mixture of the remaining components, and similarly use a mixer. The mixture was kneaded for 1 minute (hereinafter referred to as solution A).
Next, after the solution A and the solution B are quickly mixed, the entire amount of the mixture is transferred to a 200 ml cup, and the cup is sometimes tilted for a time (gel time) until the mixture does not show fluidity (gelation). It was measured by observation.

(Measurement of initial strength) The strength of the solidified body 10 minutes after gelation of the mixture was measured using a cone-type liquid limiter (using a cone having a tip angle of 60 ° C.). Was measured by a conventional method.

(Measurement of long-term strength) In a 2 liter cup, weigh 500 g of water, add 400 g of ordinary cement,
The mixture was kneaded with a mixer for 1 minute (hereinafter, referred to as solution B). Also weigh 600g of water into another 2 liter cup,
Of a total of 100 g of each composition shown in Table 3, citric acid was dissolved in water first, then a mixture of the remaining materials was added, and the mixture was similarly kneaded for 1 minute (hereinafter A).
Liquid). Next, after the solution A and the solution B are quickly mixed,
The mixture was poured into a mold to prepare a cylindrical specimen having a diameter of 35 mm and a length of 70 mm. The test specimen was cured in water, and the strength was measured at 7 days and 28 days of age using a uniaxial compression tester.

[0028]

[Table 4]

As can be seen from Table 4, the blends with small amounts of anhydrous gypsum (Comparative Examples 1 and 2) have low strength, especially the initial strength, and the blends with excessive amounts of anhydrous gypsum (Comparative Examples 4 and 4). 5) and an excess amount of sodium carbonate (Comparative Example 3) with an appropriate amount of anhydrous gypsum, but a high initial strength but a low long-term strength. On the other hand, it can be understood that the ground improvement injection material (Examples 1 to 14) of the present invention is high in both initial strength and long-term strength. Example 2
And 3, Examples 5 to 8 and Examples 9 and 10 show that the gel time increases as the amount of citric acid added increases, and that the gel time can be easily adjusted by the amount of citric acid added.

[0030]

The injection material for improving the ground according to the present invention promotes the setting and hardening of cement, easily adjusts the gel time, and has excellent initial and long-term strength development of the consolidated body. Further, the present invention can achieve effective utilization and recycling of waste through use of a rapidly hardened fired product produced from waste as an injection material for ground improvement.

Claims (3)

[Claims] 1-5 parts by weight of gypsum and 0.5 parts by weight of alkali carbonate with respect to 100 parts by weight of a rapidly hardened fired product produced from at least one of municipal waste incineration ash and sewage sludge incineration ash.
An injection material for ground improvement containing up to 30 parts by weight. 2. The injection material for ground improvement according to claim 1, further comprising 5 parts by weight or less of a setting retarder with respect to 100 parts by weight of the rapidly hardened fired product. 3. A hard-burned baked product produced from at least one of municipal waste incineration ash and sewage sludge incineration ash is C ₁₁ A ₇
One or more of CaCl ₂ , C ₁₁ A ₇ CaF ₂ , C ₃ A
40 wt% and C ₂ S, C ₃ S claim 1 or 2 soil improvement for injection material according to characterized in that it is a baked product comprising one or more.