JPH108050A - Solidifying material for soil improvement - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject solidifying material capable of exhibiting sufficient hardening properties and not causing reduction in grinding efficiency and defective blending, by blending specific quick hardening clinker composition powder with cement powder and gypsum powder. SOLUTION: This solidifying material is obtained by blending (A) 10-60wt.% of quick hardening clinker composition powder having 2,500-10,000cm<2> /g Blaine specific surface area with (B) 0.1-40wt.% of cement powder and (C) 10-60wt.% of gypsum powder. Preferably, the component A comprises a mineral phase obtained by blending a clinker raw material consisting essentially of a 12CaO.7 Al2 O3 -based calcium aluminate composed of >=50wt.% of the total of 12CaO.7 Al2 O3 -based calcium aluminate and a calcium aluminate such as 3CaO.Al2 O3 and/or CaO.Al2 O3 , etc., with 0.1-9wt.% Fe2 O3 and 0.1-9wt.% of CaF2 both based on the total amount.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ground improvement solidifying material used for ground improvement.

[0002]

2. Description of the Related Art Generally, when laying a conduit or an earth pipe through which an optical cable or an electric cable is laid in the ground,
After the soil at the position to be buried is dug back and the earth pipes are arranged, at least a work step of backfilling the ground is provided. During the work of backfilling the ground, the solidified material for soil improvement is added to the excavated soil. Is added. By the way, at the time of ground backfilling work, the reason for adding the ground improvement solidifying material is to harden the ground after backfilling in a short time to harden the ground, and as a conventional ground improvement solidification material. portland cement, blast furnace cement, jet cement [calcium silicate as a main component, 12CaO · 7Al ₂ O ₃ as a rapid hardening component (hereinafter, C ₁₂ a ₇ hereinafter) system containing calcium aluminate 20-30 wt% ], gypsum cement _{[3CaO · 3Al 2 O 3 · CaSO} 4 ( hereinafter Irwin hereinafter) as main components] and the like have been used.

[0003]

However, in recent years, as the demand for shortening the construction period has increased, there has been a demand for a solidification material for improving the ground, which has more rapid hardening properties. The rapid hardening was insufficient. Furthermore, in the conventional solidification material for ground improvement, when the ground that has been passed for a long time after the solidification material for ground improvement is re-digged for repair of earth pipes or the like, the ground becomes too hard. Therefore, there is a problem that the digging work is difficult.

[0004] The present invention has been made in view of the above circumstances, and provides a ground improvement solidifying material that has excellent rapid hardening properties of the ground after backfilling and that can prevent the ground from becoming too hard after a long time. Is to do.

[0005]

Means for Solving the Problems The present invention has been made to solve the above problems, and a means for solving the problems is to provide a hardened clinker composition having a Blaine specific surface area of 2500 to 10000 cm ² / g. It is to mix a material powder, a cement powder, and a gypsum powder.

[0006] In the present invention, such rapid hardening clinker composition powder obtained by pulverizing rapid hardening clinker composition is used as the fineness is Blaine specific surface area 2500～10000Cm ²
/ g, preferably 4000 to 9000 cm ² / g.
Here, the reason for setting the Blaine specific surface area of the rapidly hardening clinker composition powder to 2500 to 10000 cm ² / g is that if it is less than 2500 cm ² / g, the rapid hardening of the clinker powder is not sufficiently exhibited. If it exceeds 10,000 cm ² / g, poor mixing efficiency due to a reduction in pulverization efficiency and aggregation tends to occur.

[0007] As the fast hardening clinker composition, for example a calcium aluminate C ₁₂ A ₇ based as mineral phase, 3CaO · Al ₂ O ₃ (hereinafter, abbreviated as C ₃ A) and /
Or a calcium aluminate such as CaO · Al ₂ O ₃ (hereinafter CA for short), the C ₁₂ A ₇ based clinker raw material whose main component is calcium aluminate containing in its total amount 50 wt% or more, Fe 0.1 to 9% by weight of ₂ O ₃
A mixture containing CaF ₂ in an amount of 0.1 to 9% by weight based on the total weight is used.

When such a rapidly hardened clinker composition is sintered, CaF ₂ reacts with CaO and Al ₂ O ₃ to form a high-temperature melt phase of 11CaO · 7Al ₂ O ₃ · CaF ₂ (hereinafter C).
₁₁ A ₇ .CaF ₂ ) and Fe ₂ O ₃
CaO- which reacts with aO and Al ₂ O ₃ to form a low-temperature melt phase
Generating a Al ₂ O ₃ -Fe ₂ O ₃ based material.

[0009] Therefore, the generation of the high-temperature melt phase and the low-temperature melt phase increases the difference in the temperature at which these melts are formed, so that the high-temperature melt phase is used as a solid phase and the coexisting low-temperature melt phase is formed. Is the temperature range in which is the melt phase, ie, C ₁₁ A ₇ .Ca
F ₂ is not dissolved, moreover by a _{CaO-Al 2 O 3 -Fe 2} O 3 based material sintering temperature the temperature range in which the melt formation temperature difference corresponding to melting, sintering by such rotary kiln This allows the clinker to be fired.

The hardened clinker composition used in the present invention is obtained by adding Fe ₂ O ₃ to a clinker containing C ₁₂ A ₇ as a main component.
The entire 0.1 9wt%, is obtained by overall from 0.1 to 9% by weight containing coexist CaF _2.

The reason why the amount of Fe ₂ O ₃ is set in the above range is as follows. When the addition amount is less than 0.1% by weight, the amount of the low-temperature melt phase generated is insufficient, and it is difficult to produce by a sintering method using a melt as a medium such as a rotary kiln.
On the other hand, if the addition amount exceeds 9% by weight, the low-temperature melt phase will increase too much, making it difficult to produce by the sintering method using the melt as a medium, and also reducing the amount of the rapid-hardening component, Decrease.

The reason why the amount of CaF ₂ is set in the above range is as follows. If the addition amount is less than 0.1% by weight, the melt generation temperature of the high-temperature melt phase is too high, and sintering does not proceed sufficiently, which is not preferable. On the other hand, if the addition amount exceeds 9% by weight, the difference in the temperature at which the melt is produced between the low-temperature melt phase and the high-temperature melt phase becomes small, and the amount of the produced melt phase cannot be controlled. Also,
The high-temperature melt phase is excessively increased, and it is difficult to manufacture the sintering method using the melt as a medium.

The clinker containing C ₁₂ A ₇ as a main component contains 50% by weight or more, preferably 70% by weight or more of a calcium aluminate such as C ₁₂ A ₇ type, C ₃ A and CA as a mineral phase. It was included.

[0014] The C ₁₂ calcium aluminate A ₇ system, C ₁₁ A ₇ · CaF ₂ alone or C _{1 1} A ₇ · CaF ₂ and C
A mixture of ₁₂ A _7.

[0015] 50% by weight of the calcium aluminate phase
If it is less than 1, the content of C ₁₂ A ₇ which is a rapid hardening component is small, and it becomes insufficient as a clinker used for a solidification material composition for ground improvement having excellent rapid hardening, which is not preferable. . Therefore, in the clinker containing C ₁₂ A ₇ as the main component in the hardened clinker composition used in the present invention, not only the amount of the calcium aluminate phase is set to 50% by weight or more but also the viewpoint of securing the hardened property. To increase the amount of C ₁₂ A ₇ minerals as much as possible,
It is preferable to secure a calcium aluminate phase amount of 70% by weight or more.

Further, 10 to 60% by weight of the rapidly hardened clinker composition powder adjusted as described above is added to cement powder 0.1%.
It is preferable to add and mix 〜40% by weight and gypsum powder 101060% by weight. Alternatively, the hardened clinker composition powder, the cement powder, and the gypsum powder may be mixed and then pulverized. The reason why the addition amount of the cement powder is 0.1 to 40% by weight is that if the amount is less than 0.1% by weight, the amount of the rapidly hardened clinker composition powder increases, the flowability decreases, the long-term strength increases remarkably, On the other hand, if it exceeds 40% by weight, the amount of the rapidly hardened clinker composition powder is reduced,
This is because the elongation of strength in the initial period of 30 minutes to 1 hour is reduced. A more preferable addition amount of the cement powder is 10 to 40% by weight based on 10 to 60% by weight of the rapidly hardened clinker composition powder.

Further, the amount of the gypsum powder added is 10 to 60% by weight.
The reason is that if the amount is less than 10% by weight, the amount of gypsum is insufficient, so that the hydrate cannot be formed sufficiently and cannot be solidified, whereas if it exceeds 60% by weight, the amount of gypsum is large. This is because the balance of hydrate formation is lost, and the solidification performance is reduced due to the reduced amount of the rapidly hardened clinker composition powder. More preferably, the amount of the added gypsum powder is 20 to 50% with respect to 10 to 60% by weight of the rapidly hardened clinker composition powder.
% By weight.

Examples of the cement powder used in the present invention include various types of portland cement and blast furnace cement, such as commercially available ordinary, high-strength, ultra-high-strength, and sulfate-resistant cements. If it is used, the obtained solidification material composition for ground improvement becomes cheaper. As the fineness of such cement powder,
Blaine specific surface area of 2500~7000cm ² / g, preferably 3000
50005000 cm ² / g is used. Here, the reason why the brane specific surface area of the cement powder was 2500 to 7000 cm ² / g,
If it is less than 2500 cm ² / g, it will be out of the standard value of ordinary Portland cement and the hydration reactivity will be reduced.On the other hand, if it exceeds 7000 cm ² / g, the grinding efficiency will be reduced and the cement milk and treated This is because the viscosity of the soil increases and it becomes difficult to perform pumping.

The gypsum powder used in the present invention includes
Water plaster (CaSO_Four・ 2H_TwoO) etc. are used.
You. As the fineness of such gypsum powder, Blaine ratio
Surface area is 1000-3500cm^Two/ g, preferably 1200-2500cm^Two/
g is used. 1000cm ^Twoless than / g
Dissolution rate slows down, hydration reaction slows down,
No. Meanwhile, 3500cm^Two/ g, the gypsum dissolution rate is
Too good to balance the hydration product
No.

The above-mentioned solidification material for soil improvement according to the present invention is added to soil excavated during the work of backfilling the ground in the work of burying an earth pipe or the like in the ground. Here, the soil to which the solidification material for soil improvement of the present invention is added includes sandy soil, sandy loam, loam, vegetation soil, vegetation, loam, silt,
Sand, shield mud, clayey soil, and the like.

The amount of the solidification material for soil improvement of the present invention added to soil varies depending on the type of soil and the like.
About 300 kg / m ³ , more preferably about 80 to 220 kg / m ³ . If it is less than 40 kg / m ³ , strength development in a short time is extremely poor, while if it exceeds 300 kg / m ³ ,
This is because the strength increases greatly over a long period of time (after 7 days of age), making re-digging practically difficult.

Incidentally, quick lime, slaked lime and the like may be added to the solidification material for ground improvement of the present invention.

[0023]

Embodiments of the present invention will be described below.

A clinker composition having a composition shown in Table 1 was synthesized by a sintering method using a rotary kiln, and the synthesized clinker composition was ground to a Blaine specific surface area of 6500 cm ² / g to obtain a clinker composition powder of sample No. 1. I got Separately, a ground gypsum dihydrate powder was prepared. The Blaine specific surface area of the gypsum dihydrate powder was 1500 cm ² / g.
Further, commercially available ordinary Portland cement (manufactured by Sumitomo Osaka Cement Co., Ltd.) was prepared. The Blaine specific surface area of this ordinary Portland cement was 3350 cm ² / g.

Next, the obtained clinker composition powder, ordinary Portland cement and gypsum gypsum powder were blended in the proportions shown in Table 2 to obtain a sample No. 2 solidifying material for ground improvement. In addition, for comparison, we prepared Irwin-based and Jet-Cement-based soil improvement solidification materials, which are conventional soil improvement solidification materials,
These were used as solidification materials for soil improvement of samples No. 3 and No. 4, respectively.

[0026]

[Table 1]

[0027]

[Table 2]

With respect to the obtained solidification material for soil improvement of Samples Nos. 2 to 4 (Example No. 2 and Comparative Examples No. 3 and 4), a flow test and a uniaxial compressive strength A comparative test was performed in a constant temperature room at 20 ° C. according to the procedure described below.

Various types of soils such as loam (mud density 1.20), silt (mud density 1.26), sand (mud density 1.39), shield mud (mud density 1.32) and cohesive soil (mud density 1.27) are prepared. 160 kg / m ³ of the ground improvement solidification material prepared above was added to 947 L of the muddy water, and fluidized treated soils of samples Nos. 5 to 19 were obtained and subjected to each comparative test.

The flow test was performed in accordance with the test method for air mortar and air milk of the Japan Highway Public Corporation, II cylinder method (KODAN305-1985). The unconfined compression strength was determined according to the unconfined compression test method for soil (JIS A 1216). Tables 3 to 7 show these results.

Tables 3 to 7 also show the results of evaluating the performance of the fluidized soils of Samples Nos. 5 to 19. Here, the evaluation of the performance was evaluated as ○ when the property required for the fluidized soil was satisfied, and was evaluated as x when any property was not satisfied. Flow characteristics 180 to 300 mm in flow value Strength characteristics Uniaxial compressive strength after 30 minutes 0.1 kgf / cm ² or more Uniaxial compressive strength after 4 hours 1.3 kgf / cm ² or more Uniaxial compressive strength after 28 days 5.6 kgf / cm ² or less (permanent)

[0032]

[Table 3]

[0033]

[Table 4]

[0034]

[Table 5]

[0035]

[Table 6]

[0036]

[Table 7]

As is clear from the results shown in Tables 3 to 7, the fluidized treated soil (sample NO. 2) to which the solidification material for soil improvement of this embodiment (the solidification material for soil improvement of Sample No. 2) was added. .6,9,
12, 15, 18) satisfy all of the above-mentioned characteristics, which are the performance required for fluidized soil, compared with conventional solidification materials for soil improvement (samples No. 3, 4) No.5, 7, 8, 10, 11, 13, 1
4,16,17,19) cannot satisfy all of the above characteristics, especially the uniaxial compressive strength after 4 hours is 1.3kgf
/ cm ² and the uniaxial compressive strength after 28 days was 5.6 kgf / cm ² or less (permanent). Therefore, the solidification material for ground improvement of this example (solidification material for ground improvement of sample No. 2)
Fluidized treated soil (Sample Nos. 6, 9, 12, 15, 1)
8) indicates that the fluidized soil has excellent rapid hardening properties and can prevent the fluidized soil after a long time from becoming too hard.

Next, 4000 cm ² / g Blaine specific surface area of rapid hydraulic clinker composition, 6000cm ² / g, except for changing the 8000 cm ² / g, the same soil improvement for solidifying material and sample NO.2, The same test as described above was performed on loam soil (Examples 21 to 23), and the hardened clinker composition was compared with the case where the Blaine specific surface area was 1500 cm ² / g and 11000 cm ² / g (Comparative Example 20, twenty four ).

Table 8 shows the results.

[0040]

[Table 8]

As is clear from Table 8, in the case of Comparative Example 20 in which the Blaine specific surface area of the rapidly hardening clinker composition is low, although fluidity is obtained, strength is not stable due to unstable properties such as filling property. I can't get it.

On the other hand, in the case of Comparative Example 24 in which the hardened clinker composition has a high Blaine specific surface area, the fluidity is inferior and the strength is more than desired.

In this respect, in Examples 21 to 23, the fluidity,
Neither of the drawbacks in terms of the filling property occurred, and in particular, Example 22 satisfied all the properties of flowability, homogeneity, and strength.

[0044]

As described above, the solidifying material for ground improvement of the present invention is obtained by setting the Blaine specific surface area of the rapidly hardening clinker composition powder as a component thereof to 2500 to 10000 cm ² / g. The clinker powder also has an effect that the rapid hardening property is sufficiently exhibited, and the mixing efficiency does not decrease due to the reduction of the pulverization efficiency or the aggregation.

Also, the hardened clinker composition powder 10 to 60
0.1-40% by weight of cement powder and gypsum powder
A solidifying material used in the mixed soil improvement comprising a 10 to 60% by weight, the sudden hard clinker composition, calcium aluminate C ₁₂ A ₇ based as mineral phase, C ₃ A and / or a calcium aluminate of the CA or the like, the C ₁₂ a ₇ based clinker raw material whose main component is calcium aluminate containing in its total amount 50 wt% or more, Fe ₂ O ₃
The entire 0.1 9wt%, when allowed to total 0.1 to 9% by weight containing coexist CaF ₂ is easily manufactured by using a rotary kiln or the like suddenly rigid clinker composition to sinter the melt as a medium It has the advantage of being

Further, when a rapid-hardening clinker composition powder having a high content of a fast-hardening component is contained, the powder is added to soil excavated during backfilling of the ground, thereby improving the conventional ground improvement. Compared to the case where a solidifying material is used, since the ground after backfill hardens in a short time, there is an advantage that rapid hardening is excellent, and the period for burying an earth pipe or the like can be shortened.

Also, by adding to the soil excavated during the work of backfilling the ground, the ground after a long period of time can be prevented from becoming too hard, and the ground can be repaired again for repairing the soil and the like. There is also an advantage that the work when excavating is easy.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification number Agency reference number FI Technical display location // C09K 103: 00 (72) Inventor Nobuaki Shiokawa 7-55 Minamienkajima, Taisho-ku, Osaka-shi No. Sumitomo Osaka Cement Co., Ltd. Central Research Institute Cement and Concrete Research Laboratory (72) Inventor Masahiro Yoshihara 7-55 Minamienkajima, Taisho-ku, Osaka City Sumitomo Osaka Cement Co., Ltd. Cement Research Laboratory In-house (72) Inventor Yasushi Mendaka 7-55 Minamienkajima, Taisho-ku, Osaka Sumitomo Osaka Cement Co., Ltd.

Claims (3)

[Claims] 1. A solidifying material for ground improvement, comprising a mixture of a rapidly hardening clinker composition powder having a Blaine specific surface area of 2500 to 10000 cm ² / g, a cement powder and a gypsum powder. 2. The hardened clinker composition according to claim 1, wherein the mineral phase is 12CaO.7Al ₂ O ₃ -based calcium aluminate, 3CaO.Al ₂ O ₃ and / or CaO.Al ₂ O _3.
And a calcium aluminate containing, as a main component, 12CaO.7Al ₂ O ₃ -based calcium aluminate containing 50% by weight or more of Fe ₂ O ₃
The entire 0.1 9wt%, made by the entire 0.1 9wt% containing coexist CaF ₂ claim 1 soil improvement for solidifying material according. 3. The rapid-curing clinker composition powder according to claim 1, wherein
3. The solidification material for soil improvement according to claim 1, wherein 0.1 to 40% by weight of cement powder and 10 to 60% by weight of gypsum powder are mixed with 60% by weight.