JPH06306841A - Soil composition - Google Patents

Abstract

(57) [Summary] [Purpose] In a soil composition containing soil, a hydraulic material, water and a foam, uniform mixing is maintained for a long time,
Provided is a soil composition which does not become non-uniform before hardening. [Constitution] Soil, hydraulic material, water, foam and SiO ₂ concentration 1 ~
A soil composition consisting of a uniform mixture of fine particles of 60% by weight silica aqueous jelly.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a soil composition for forming a lightweight soil material. This soil composition has high fluidity and hardenability, and the hardened material is used as a homogeneous lightweight soil material for constructing embankments, retaining wall soil and the like.

[0002]

2. Description of the Related Art Conventionally, soil materials used to construct earth structures such as embankments and backfill soil on the back of retaining walls are natural soil and industrial by-products mixed with a solidifying material such as cement, water and foam particles. Made from earthy slurry. Japanese Unexamined Patent Publication (Kokai) No. 4-14511 discloses a lightweight soil composition for water casting, which comprises soil, cement, water, expanded particles and water glass.

[0003]

However, when a slurry composed of a mixture of soil, cement, water, and expanded particles as described above is applied to the construction, the slurry is initially uniform, but with the passage of time, Before curing the slurry,
The foamed particles are easily floated on the upper part of the slurry, and in many cases, a uniform cured product of the slurry cannot be obtained.

A slurry obtained by further mixing water glass into this slurry as disclosed in Japanese Patent Application Laid-Open No. 4-14511 has a short curing time, for example, it is cured in a few seconds to a few minutes. Since it shows a quick-setting property, it is easy to obtain a uniform hardened material, but it is difficult to use it for embankment construction that requires a considerably long working time, backfilling of the back of the retaining wall, etc. The present invention, in a soil composition containing soil, cement, water and expanded particles, the uniform mixed state lasts for a long time, does not cause non-uniformity before hardening, the workability is improved. It is intended to provide a soil composition.

[0005]

Means for Solving the Problems The soil composition of the present invention comprises
It consists of a homogeneous mixture of soil, foam, hydraulic material, water and fine particles of silica aqueous jelly having a SiO ₂ concentration of 1 to 60% by weight. The soil used in the present invention may be natural soil such as sandy soil or cohesive soil and is not particularly limited. The foam used in the present invention is not particularly limited, for example, polystyrene,
Examples thereof include granular foams of synthetic resins such as polyethylene, polypropylene, polyurethane, polyvinyl chloride, and epoxy resin, or foams obtained by stirring an aqueous solution of a water-soluble resin such as a surfactant, animal protein or urea resin. .

The hydraulic material used in the present invention includes:
For example, ordinary Portland cement, early-strength Portland cement, blast furnace cement, gypsum and the like can be mentioned. The silica aqueous jelly used in the present invention usually has a SiO ₂ content of 1 to 60.
% By weight, preferably 3 to 30% by weight. This silica aqueous jelly can be easily obtained by a known method.
Examples thereof include various acids and salts in an aqueous solution of a water-soluble silicate such as water glass, for example, sulfuric acid, hydrochloric acid, acetic acid, citric acid,
Method of adding salt, magnesium sulfate, etc., or
Examples thereof include a method of gelating an aqueous solution of silicic acid or an oligomer thereof obtained by decationizing an aqueous solution of a water-soluble silicate such as water glass, or a method of gelling an aqueous silica sol by a known method. . An example of the silica aqueous sol is that which normally contains 1 to 60% by weight, preferably 3 to 30% by weight of SiO ₂ and has a particle diameter of 1 to 150 mm, preferably 10 mm or less. And an aqueous sol of colloidal silica having a high surface activity.

The soil composition of the present invention comprises 100 parts by weight of the soil and 0.001 to 90 parts by weight of the foam, preferably 0.005 to
60 parts by weight and 5 parts by weight or more of the above hydraulic material, preferably
10 to 300 parts by weight, the above silica aqueous jelly 2 to 1500 parts by weight, preferably 20 to 1000 parts by weight, and water 5 to 2000 parts by weight,
Preferably, it is easily obtained by uniformly mixing with 50 to 1200 parts by weight by vigorous stirring.

The soil composition of the present invention can also be obtained by using the above silica aqueous sol instead of the silica aqueous jelly in the above mixing. The soil composition of the present invention can contain any component in addition to the above components as long as the object of the present invention is achieved. The order of mixing the above components is not particularly limited and may be arbitrary. The temperature of the mixing is a temperature higher than the freezing point of water, such that the obtained soil composition does not thicken,
Room temperature is preferable. And the said mixing can be performed by stirring for several minutes to about 10 minutes in a normal stirrer.

[0009]

The silica aqueous jelly mixed in the soil composition of the present invention does not change the composition to a heterogeneous state within a time period shorter than the time when the soil composition starts to harden. It has been found to be effective in stabilizing. Its physical action is still unclear, but perhaps when this added jelly is mixed with other ingredients under vigorous stirring, the large particles are subdivided and dispersed in the composition as fine particles to give this composition. While giving an appropriate viscosity to the object,
It is considered that the surface of the fine jelly particles has a high affinity with the surface of the added soil particles, cement particles, foamed particles, etc., and acts to prevent sedimentation of these heavy particles and floating of the light particles. Also, when a silica aqueous sol is added, the sol reacts with the calcium component-derived calcium component to form a jelly, and when the jelly is mixed with other components under the above-mentioned strong stirring, a large jelly is obtained. The particles are subdivided and mixed into this composition as fine jelly particles, and it is considered that the particles behave in the same manner as in the case of using the above silica aqueous jelly.

However, the preferred soil composition is obtained by mixing the components in the desired proportions with stirring. If the amount of the foam exceeds 90 parts by weight with respect to 100 parts by weight of the soil, a homogeneous composition cannot be obtained. On the contrary, if it is less than 0.001 part by weight, the specific gravity becomes large and a lightweight cured product cannot be obtained. If the hydraulic material is less than 5 parts by weight with respect to 100 parts by weight of the soil, the obtained cured product will not show sufficient strength.
To 100 parts by weight of the above soil, silica aqueous jelly or sol
When it exceeds 1500 parts by weight, stirring tends to be difficult during the above mixing, while when it is less than 2 parts by weight, the composition does not have sufficient stability. If the amount of water exceeds 2000 parts by weight with respect to 100 parts by weight of the soil, the stability of the composition will be insufficient and the water will easily float. On the other hand, if it is less than 5 parts by weight, stirring will be difficult during the mixing. .

[0011]

[Example] Ordinary Portland cement was used as the hydraulic material, and clay adjusted to a water content ratio of 80% by weight was used as the soil. As the silica aqueous jelly, a jelly obtained by gelling an aqueous solution of silicic acid having a SiO ₂ concentration of 4% by weight and its oligomer by allowing it to stand at room temperature was prepared. Also, as an alternative to this jelly, SiO ₂ concentration of 15
A wt% silica aqueous sol was prepared.

The water glass used in the comparative example is JI
S3 sodium water glass was prepared. As the foam, expanded beads of polystyrene resin with a particle diameter of 2 mm (specific gravity
0.03) was prepared. Further, as a substitute for this foam, a commercially available surfactant Snow Wrap (trade name) was added during preparation of the soil composition to directly foam the soil composition for use.

The soil composition was prepared by introducing the above-prepared components into a commercially available biaxial stirrer and stirring at room temperature for 5 minutes. The obtained soil composition has a diameter of 5 cm and a length of 50
After curing in a bag made of semi-transparent plastic film of cm for one week, 5 cm from the lower end of the obtained bar-shaped cured product was cut off, and the next 10 cm was used as a lower cured body sample. The next 10 cm portion was taken as a middle hardened body sample, and the next 10 cm portion was taken as an upper hardened body sample.

Example 1 In experiment number 1 of this example, a water / cement weight ratio of 0.
71, soil / cement weight ratio 2.0, silica aqueous jelly / cement weight ratio 1.0, surfactant / water weight ratio 0.10 were prepared, and in Experiment No. 2, surfactant / water weight ratio A soil composition was prepared in the same ratio as in Experiment No. 1 except that the ratio was 0.50.

Next, the specific gravity and the compressive strength of the hardened samples obtained from these soil compositions were measured. In Experiment No. 3 of Comparative Example, a soil composition was prepared in the same manner as above except that no surfactant was added, and a hardened body sample obtained from the composition was measured. In Experiment No. 4 of Comparative Example, a soil composition was prepared in the same manner except that silica sol was not added. However, before the composition was cured, water and bubbles floated in the upper part of the bag, and the composition was Specific gravity and compressive strength were not measured due to loss of homogeneity.

The results of the above measurements are listed in Table 1. Table 1 Experiment number Surfactant / water Specific gravity (g / cm ³ ) Strength (kg / cm ² ) Weight ratio Upper middle lower Lower upper middle lower 1 0.1 0.81 0.84 0.83 3.07 3.18 2.90 2 0.5 0.64 0.66 0.68 1.74 1.96 2.24 3 0.0 1.37 1.38 1.40 8.68 8.79 9.95 After the soil composition was prepared at a weight ratio of cement of 2.0, a volume ratio of expanded beads / soil of 1.8, and a weight ratio of silica aqueous sol / cement of 1.0, the hardened material was measured in the same manner as in Example 1. .

Experiment No. 2 of the comparative example was conducted in the same manner as Experiment No. 1 except that the silica aqueous sol was not added. The measurement results are shown in Table 2. Table 2 Experiment number Sol / water specific gravity (g / cm ³ ) Strength (kg / cm ² ) Weight ratio Upper middle lower upper middle lower 1 1 1.0 1.01 1.03 1.04 2.35 2.42 2.40 2 0.0 0.36 1.20 1.60 0.28 15.6 18.4

[0018]

EFFECTS OF THE INVENTION According to the present invention, in the conventional preparation of a lightweight soil composition, by adding silica aqueous jelly or sol as an additional component, a lightweight soil composition can be maintained for a long time. A composition is obtained. The cured product has a uniform strength and is useful as various soil structures.

The soil composition of the present invention has stability and fluidity, and has excellent workability. For example, in field construction, pipe transportation, long-distance pressure feeding, filling into a narrow space, etc. can be easily performed.

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Claims (1)

[Claims] 1. A soil composition comprising a homogeneous mixture of soil, foam, hydraulic material, water and fine particles of silica aqueous jelly having a SiO ₂ concentration of 1 to 60% by weight.