JPS58109584A - Soil stabilizer - Google Patents

Abstract

PURPOSE:A solid stabilizer with excellent chemical stability, processability and initial strength safely applicable in a working field contg. low-temp. water, which is prepd. by adding CaCl2, a sulfate and a strength developing agent to a cement suspension. CONSTITUTION:To a cement suspension are added 0.01-1.0pts.wt. CaCl2, 0.01- 1.0pts.wt. at least one sulfate selected from Na, K, Mg, Al and Fe sulfates, Na and K bisulfates, and Na and K sulfites, and 0.001-2pts.wt. strength developing agent such as CaSO4 each based on 1pts.wt. cement. Then the suspension is mixed with water glass of mol or ratio >=3.0 in such a proportion that 0.2- 5pts.wt. cement is contained for 1pts.wt. water glass. EFFECT:Initial strength which a cured product exhibits one day after cured is higher than that applicable in uniaxial compression strength.

Description

[Detailed Description of the Invention] The invention is based on the so-called LW '1 method, a soil stabilization method that uses a (cement-water glass) chemical solution for soil treatment such as water stopping and solidification of the ground. It relates to soil stabilizers with improved initial strength and work stability.

Conventionally, LW-based chemical solutions have been widely used for the purpose of soil treatment, but in recent construction, so-called instant setting mLW grout, which has a short gel time, is desired. The main reason for this is that if the target ground is soft and cohesive soil, plastic deformation is likely to occur, so if LW grout with a long gel time is used, the grout will spread over a wide area through the fractured veins. This is because there is a tendency for the water to dissipate, which may result in uneven improvement or cause harm from the alkali.

The method to shorten the gel time of this grout is (1
) increasing the cement concentration; (2) using early-strengthening cement (including ultra-early-strengthening colloids) such as microcrystalline alumina cement or portland cement; (3) adding metal salts such as calcium chloride and gypsum to cement milk. (4) molar ratio of water glass (SiO2/Na2O)
However, these methods have the following drawbacks.

(1) It is generally difficult to set the gel time to 10 seconds or less. Especially when diluting water with low water temperature in cold regions is used, the gel time of LW grout tends to be extremely delayed. (2) Depending on the additive, the liquid viscosity on the cement milk side may be high, making stable pump suction difficult, resulting in unstable mixing ratio of water and glass liquid, and mixing time. You won't be able to get enough of it. (3) Calcium chloride (% Kosho+9-1IA?A/No.) and gypsum hemihydrate (JP-A-33-71.1.10.3), which are known as gel time accelerators for (cement-water glass)-based chemical solutions. (No. 3), etc., the viscosity of cement slurry increases over time due to cement agglomeration or its own hydration self-hardening properties, resulting in problems with workability such as stirring, and transportation such as sedimentation hardening within the liquid supply hose. Trouble may occur. (4) If the water glass used is limited to water glass with a high molar ratio, it will lack versatility when used in combination with other water glass hardening agents.
(5) Cost will increase.

The present inventors have found that it has a preferable gel time as a flash-setting grout, can be stably installed even at sites with low water temperatures (below 10°C), has excellent chemical stability and workability, and is also suitable for use after gelling. The initial strength (1 day after curing) of the cured product is -
As a result of intensive research into grout compositions that exhibit axial compressive strength that is at least workable, it was discovered that excellent effects can be obtained by using calcium chloride and sulfate in combination, and this led to the completion of the present invention. It was.

That is, the present invention provides a soil stabilization method using a (cement-water glass) based chemical solution, in which (a) calcium chloride, (
'b) A soil stabilizer characterized by comprising a sulfate, and further Na as the sulfate.

K, Mg, Aj, Fe sulfate, Na,
It is characterized by being composed of seven or more selected from K bisulfate, Na, and Ni sulfite.

The mechanism of the effect on promoting gel time and increasing initial strength in the present invention is considered to be due to the following synergistic effect. That is, (1) the exothermic reaction accompanying the dissolution of calcium chloride causes an increase in the temperature of the dilution water used, resulting in a gel time promoting effect even under working conditions in cold regions.

(2) Slightly soluble calcium sulfate hydrochloride produced from dissolved calcium chloride and sulfate is extremely fine and activated, and acts prominently as an early strength developer during the hardening action of LW grout. -7 The amount of calcium chloride and sulfate added can vary widely depending on the desired gel time, but usually O1θl ~ 7.0 parts by weight per 7 parts by weight of cement, preferably 0.0:1-0
．． There are 3 intake parts.

When preparing a cement suspension, there is no particular restriction on the order of addition between cement, calcium chloride and sulfate, but it is preferable to dissolve calcium chloride and sulfate before suspending the cement. .

The cement and water glass used in the present invention may be of any type conventionally used for grouting in this building;
The water glass preferably has a molar ratio of 3.0 or more, such as No. 3 or No. 7 water glass.

The blending amount of water glass is usually 0.2 to 3 parts by weight of cement per 1 part by weight (in terms of pure water glass).

In addition, a strength-enhancing agent having pozzolanization and cement bacillus-forming effects may be added to the above-mentioned drug to the extent that the effects of the present invention are not impaired. For example, (1) aluminum compounds such as aluminum metal powder and aluminum oxide, (2) limes such as quicklime and slaked lime, (3) calcium salts such as calcium sulfate, calcium carbonate, and dolomite, (4) blast furnace water slag, and dry phosphoric acid. It is composed of one or more slags selected from slags such as rinsing slags that are discharged from the manufacturing process and whose main component is wollastonite. 00/~ parts by weight.

In addition, various surfactants such as naphthalene type, creosote oil type, melamine type, lignin type, polyol type, acidic organic phosphoric acid, etc. are used as dispersants and viscosity modifiers.
Organic phosphorus compounds such as organic phosphorous acids, organic phosphonic acids, and their respective metal salts can also be added.

The present invention will be explained below with reference to Examples, but the present invention is not limited thereto.

Example/ ! f, 10. /S, Calcium chloride and various sulfates, to 2 ml of water adjusted to a constant temperature of 20°C.
A strength enhancer was added and stirred, and ordinary Portland cement 1IOFI was further dispersed to prepare a cement suspension.

60d or jt of water at the same temperature used for cement suspension preparation for J3 wooden sword lath yomt or 30rnl
Diluted with Oml and mixed with cement suspension.

For Examples and Comparative Examples, the gel time was measured according to the temperature of the water used, and the results are shown in Table 7 together with formulation examples. From the table, it can be seen that the gel time of the present invention is IO-20 seconds even at low temperatures (5° C.), and exhibits superior instant setting properties compared to the comparative example.

Example: Add water bod to No. J3 wooden sword Las'l01d to make liquid A.
Ordinary Portland cement for 2m of water! ;09, calcium chloride, sulfate, and a strength enhancer were dispersed to prepare B solution. Curing gel time (,2θ
℃) The unconfined compressive strength was measured at 7 minutes, 10 minutes, 1 day, and 3 days after curing, and is shown in Table 1 along with formulation examples.

Example 3 Changes in the viscosity of a cement (Cement) M suspension having the same formulation as in Example 3 were measured over time, and the results are shown in Table 3. It can be seen from Table 3 and Cloth 3 that the unconfined compressive strength and viscosity of the cement suspension of the present invention are sufficiently workable.

Claims (1)

[Scope of Claims] l Cement suspension - a soil stabilizer consisting of a water glass-based chemical, further containing calcium chloride and/a selected from sulfates, bisulfates, and sulfites, or two or more of them. A soil stabilizer characterized in that a salt is present in a cement suspension, wherein the sulfate is Na, M#, A4. The soil stabilizer according to claim 7, wherein the sulfate of Fθ, the bisulfate of Fθ is Na, the bisulfate of Fθ, and the sulfite of Fθ are Na and sulfite of Ni. 3 Claims in which 0.07 to 1.0 parts by weight of calcium chloride and one or more salts selected from sulfates, bisulfates, and sulfites are present based on 3 parts by weight of cement. The soil stabilizer according to item 1 or 2. DA Cement Suspension - In a soil stabilizer consisting of a water glass-based chemical solution, seven or more salts selected from calcium chloride, sulfates, bisulfates, and sulfites and a strength enhancer are added to the cement suspension. A soil stabilizer characterized by being present in a liquid. 3. The soil stabilizer according to claim 1, wherein the strength enhancer is /fa or one or more of aluminum metal powder, aluminum oxide, quicklime, slaked lime, calcium sulfate, calcium carbonate, dolomite, blast furnace slag, rinsing slag, etc. . 6. Calcium chloride and one or more salts selected from sulfates, bisulfates, and sulfites per 1 part by weight of 0.07 to 0 parts by weight, and 0 parts by weight of a strength enhancer. The soil stabilizer according to claim 4 or claim S, which is present in an amount of .00/~- parts by weight.