JPS61281191A - Soil conditioning material - Google Patents

Abstract

PURPOSE:An economic soil conditioning material, changing fragile ground into improved hard ground having high uniaxial compression strength, providing fast roadbeds having high CBR in road construction, using effectively coal ash, consisting of cement and the coal ash. CONSTITUTION:A soil condition material such as ground reinforcing material, roadbed reinforcing material, etc., consisting of (A) usually 5-95wt% cement (comprising preferably calcium oxide, silicon dioxide, aluminum oxide, sodium oxide, potassium oxide and sulfur trioxide as main components) and (B) usually 95-5pts.wt. coal ash.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a soil improvement material, and more particularly.

In particular, the vulnerable i′1! As a reinforcement material for the board, or
This invention relates to a soil improvement material useful as a roadbed reinforcement material during road construction.

[Prior Art] When constructing a building on weak or soft soil such as a reclaimed land, it is necessary to first strengthen the soil prior to construction.

On the other hand, when building a road, it is common to sequentially form a roadbed layer and a pavement layer on the roadbed. In this case, roads are required to maintain their robustness against changes in temperature and continuous physical and mechanical loads from winter to summer. To do this, first of all, the underlying roadbed must be solid.

In this way, for the purpose of strengthening the ground or roadbed,
Conventionally, it has been common to use so-called soil improvement materials, and concretely, cement is well known. That is,
As a soil improvement material for reinforcing the roadbed, ordinary cement such as Portland cement can be used, and as a soil improvement agent for ground reinforcement, cement whose composition is slightly different from the above-mentioned ordinary Portland cement, that is, Calcium oxide (Cab), silicon dioxide (Si02),
Aluminum oxide (AC203), sodium oxide (
Cement based on Na20), potassium oxide (K2O) and sulfur dioxide (SO3) are used, respectively.

[Problem to be Solved by the Invention J] When such cement is used as a soil improvement material for ground reinforcement or roadbed reinforcement, the respective strengthening effects are relatively excellent; however, the strength of the ground is The unconfined compressive strength, which is an indicator of subgrade strength, and the subgrade soil bearing capacity (JR), which is an indicator of subgrade strength, are both not in a fully satisfactory state, and there is still room for improvement. There is.

[Means for Solving the Problems] The present invention, in response to such conventional demands, provides a ground with high unconfined compressive strength when used for ground reinforcement.

On the other hand, when used as a subgrade reinforcement material, it has a high subgrade bearing capacity (CB).
The purpose of the present invention is to provide a soil improvement material that can be applied to roadbeds having R).

The present inventors have conducted intensive research to find an additive that can further improve the reinforcing effect by adding it to the conventional cement material described above. The present invention was completed after confirming that the soil reinforcement material obtained by blending it into cement materials has excellent effects.

That is, the soil improvement material of the present invention is characterized by comprising cement and coal ash.

The blending amount of both is determined as appropriate depending on the purpose of the soil improvement material or the composition of the cement used, but usually,
It is preferable to set the total amount to 100 parts by weight of 5 to 95 parts by weight of cement and 95 to 5 parts by weight of coal ash.

[Specific Description] The coal ash used in the present invention is not particularly limited as long as it is produced by combustion of coal, but in particular, coal ash obtained by combustion of bituminous coal, such as 5i02, xi2o3 , iron oxide (Fe203/F
e304), CaO etc. as main components
) t* is preferred. In recent years, due to changes in the energy situation, coal has been reconsidered as a variety of fuels, so the present invention is extremely useful from the perspective of effectively utilizing coal ash produced after burning coal.

The soil improvement material of the present invention is roughly divided into the following two types depending on the composition of the cement used in combination with coal ash.

First, a soil conditioner made of coal ash and ordinary cement such as Portland cement is suitable as a roadbed reinforcement material. In this case, the blending amount of coal ash and cement is preferably set to 95 to 5 parts by weight of coal ash to 5 to 35 parts by weight of cement, and more preferably 10 to 80 parts by weight of cement and 80 to 20 parts by weight of coal ash. It is preferable to use parts by weight, and when using such soil improvement materials to strengthen the subgrade,
10 to 90 parts of soil conditioner per 100 parts by weight of the subgrade
It is preferable to set the amount by weight, preferably 30 to 80 parts by weight.

Next, a soil reinforcing material made of coal ash and cement, which has been conventionally used as a ground reinforcing material as described above, has a particularly excellent function as a ground reinforcing material. That is, such cements include CaO, 5i02.
j! 4203, Na2O, K2O and SO3 as main components are preferable, and the blending amount of each is Ca
b: 50-fio wt%, 5i02: 10-20 wt%, A1203: 2-10 wt%, Na2O+
K2O: 0.5 to 2% by weight, S03: preferably about 4 to 15% by weight, and the blending ratio of such cement and coal ash is not particularly limited, but cement is 20 to 90% by weight. Coal ash 80~IO to parts by weight
It is preferable to set the total to 100 parts by weight, and further, 30 to 80 parts by weight of cement,
It is preferable to set the amount of coal ash to 70 to 20 parts by weight.

Furthermore, when such a soil improvement material is used as a ground reinforcement material by mixing it with mud, for example, mud! It is preferable to use 3 to 30 parts by weight of the soil conditioner to 00 parts by weight.

[Example] Examples 1 to 6, Comparative Example 1 Cement and coal ash were mixed in the amounts shown in Table 1 to prepare a soil improvement material. The cement has a composition that has traditionally been used as a soil conditioner, with CaO: 5
7.0%, 5i02: 17.3% by weight, A, Q203
:4.311%, Na2O+K2O: 0.9% by weight
, S03:11.1fi% composition ratio was used. The coal ash used was obtained from Australian Avadi 7 coal and had an average particle size of 25 μm.

100 parts by weight of each of the soil improvement materials obtained in this way was mixed with 660 parts of mud as shown in Table 1, and the -axial compressive strength was measured, and the results are shown in Table 1. It was shown to. However, the measurement of -axial compressive strength is in accordance with JIS A 12.
The test was conducted 28 days after the test in accordance with 18.

Table 1 Examples 7 to 12. Comparative Examples 2 to 9 Portland cement manufactured by Tokuyama Soda ■ was used as the cement.
In addition, coal ash obtained from Australian Aberdare coal with an average particle size of 25 mm was used, and this and subgrade soil were mixed in the proportions shown in Table 2 to form a subgrade. , the subgrade bearing capacity ratio (CBR) was measured for each, and the results are shown in the table. The method for measuring CBH will be described below.

What is CBR?Ca1ifornia Bearing R
Abbreviation for atio, which is an index that expresses the strength of subgrade soil. First, the soil at the target location was collected without changing its moisture content, and placed in three layers in a mold with an inner diameter of 150 mm and a height of 175 cm. Each layer was compacted 67 times by placing a load plate on it, and soaked for 4 days. Soak. Place the piston on the specimen thus obtained, apply a load smoothly so that it penetrates the specimen at a rate of 11 cm per minute, and record the amount of penetration. The load applied to the penetration piston at the specified penetration amount, that is, the test unit load, is determined, and the CBR is determined using the following formula.

Standard unit load Standard unit load and test unit load are usually penetration amount 2.51
Takes the value in the intestine. Therefore, the greater the load on the penetrating piston, the greater the BR of the material.

Table 0'S2 [Effects of the Invention] As is clear from the explanations to the north, the soil improvement material of the present invention can be used as a reinforcement for weak ground, providing solid ground with high axial compressive strength, while also being useful for road construction. CB as a roadbed reinforcement material
Since it provides a solid roadbed with high H, its industrial value is extremely large in the fields of construction and civil engineering work.

Furthermore, since the soil improvement material of the present invention is made by blending coal ash with Saint material, which is a conventional improvement material,
It is extremely economically useful from the perspective of effectively utilizing coal ash produced by burning coal.

Claims (1)

[Claims] 1. A soil improvement material comprising cement and coal ash. 2. The blending amount of the cement is 5 to 95 parts by weight, the blending amount of the coal ash is 95 to 5 parts by weight, and the total of both is 1.
00 parts by weight of the soil improvement material according to claim 1. 3. The soil improvement material according to claim 1 or 2, wherein the cement contains calcium oxide, silicon dioxide, aluminum oxide, sodium oxide, potassium oxide, and sulfur trioxide as main components. 4. The soil improvement material according to claim 1, wherein the soil improvement material is a soil reinforcement material. 5. The soil improving material according to claim 1, wherein the soil improving material is a roadbed reinforcing material.