JPS6361355B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for preparing a lightweight cellular filler that has good filling properties, is lightweight, and has little material separation, which is mainly composed of soft granulated granulated slag with controlled particle size. For example, cavity filling materials used to fill underground cavities such as abandoned coal mine tunnels, abandoned buried pipes, and abandoned air defense moats, or cavities or voids between structures and the ground caused by ground subsidence, have the following characteristics. It is hoped that (1) Good fluidity during injection. (2) Pot life (time until curing) can be freely adjusted according to site conditions. (3) Less breathing (separation phenomenon). (4) Filling material for ground subsidence should be lighter than conventional ground. (5) The unconfined compressive strength should be slightly higher than that of the conventional ground. (6) When support piles exist in a cavity created by subsidence, the adhesion strength of the filler material is small and should not prevent subsequent subsidence due to adhesion to the support piles. The conventional method for preparing a cavity filler using granulated slag is to introduce a foaming agent into a foam manufacturing device to form air bubbles, add the formed air bubbles to other mixed materials that have been mixed in advance, and then This was a preform method in which air bubbles were introduced into the filler by kneading it until it became homogeneous. While the preform method is a suitable method for preparing fillers with the aforementioned desirable properties,
The equipment was complex and required unique technology, production management was extremely difficult, and there were also problems in terms of economy. Other fillers are known, such as bentonite mortar made of cement, bentonite, sand, and water, and bacillus mortar made of alumina, lime, gypsum, sand, and water.
None of these have sufficient properties as the desired filler described above, and are relatively expensive as a cavity filler, so an inexpensive filler is desired. The object of the present invention is to provide a method for preparing a cavity filler that overcomes these conventional drawbacks. The present invention basically belongs to the so-called mixed foam method, in which a foaming agent is added at the same time as materials are kneaded and mixed, and air bubbles are included in the prepared slurry. By using it as a main component, we aim to provide a method for preparing a lightweight foam filler with good fluidity, light weight, little breathing, and low cost through simple operations. The present inventors have confirmed the following points as a result of various studies on the characteristics of cement mortar using fine aggregate as granulated slag, which has been crushed and adjusted in particle size, by varying the amount of fine powder of granulated slag. did. (1) When the amount of 0.149 mm sieve in the granulated slag increases, the strength of cement mortar after hardening increases due to the alkali stimulation of Portland cement. (2) The strength development property of the finely powdered granulated slag is about one-half to three-fourths that of Portland cement, and the amount of cement per unit can be reduced. (3) As the amount under the 0.149 mm sieve in the granulated slag increases, the viscosity of the mortar also increases almost proportionally. The present invention was completed based on the above findings, and consists of a soft granulated slag with particle size adjustment of 360 to 410 with a particle size of 15% or more under a 0.149 mm sieve, a unit cement amount of 95 to 125 kg, and a water/cement ratio. A foaming agent, a water reducing agent, and a viscosity agent are added to a slurry consisting of 250 to 350% by weight of 0.4 to 0.4 parts by weight of each 100 parts by weight of cement.
A method for preparing a cavity filling material, which comprises adding 0.7 parts by weight, 0.2 to 0.3 parts by weight, and 0.4 to 0.6 parts by weight and stirring to prepare a lightweight cellular grout material containing 25 to 30% air by volume. It is. The present invention uses as a main component soft granulated slag whose particle size has been adjusted to be 15% or more under a 0.149 mm sieve. Granulated slag is made by blowing molten slag discharged from a blast furnace using pressurized water. The granulated slag used in the present invention is selected from ordinary soft granulated slag with a unit volume weight of 0.85 kg/or less, and crushed to adjust the particle size. The basic principle is to adjust the particle size so that it is 15% or more. FIG. 1 shows an example of the relationship between the unit volume weight of soft granulated slag and the crushed particle size when the soft granulated slag is crushed under the same crusher conditions. The crushed particle size is sieve mesh 0.149mm
It is expressed as the amount of passage. From Figure 1, it is recognized that the smaller the unit volume weight of granulated slag (i.e., lighter granulated slag), the greater the crushability and the finer the crushed particle size. If you select and use
It is possible to secure granulated slag with a particle size of 15% or more under the 0.149mm sieve. Granulated slag can increase the strength of the prepared filler, increase the viscosity, and reduce the amount of cement used, when the 0.149mm sieve is more than 15%
If it is less than this, these effects will be small and breathing will increase, impairing the suitability of the filler. Furthermore, the granulated slag used in the present invention has the following properties: Maximum particle size: 2.380mm Amount passing through 1.190mm sieve 95% or more 〃 0.590mm 〃 70% 〃 〃 0.279mm 〃 40% 〃 〃 0.149mm 〃 15% A slag with a particle size distribution is optimal. When using the above-mentioned granulated slag whose particle size has been adjusted, a unit cement amount of 95 to 125 kg can provide sufficient strength as a cavity filling material. If the unit cement amount is less than 95 kg, strength development is insufficient and 125
If the weight exceeds Kg, the strength becomes unnecessarily high and is limited from an economical point of view. If the water/cement ratio is less than 250% by weight, there will be problems in terms of strength, light weight, and economical efficiency of the prepared grout, and if it exceeds 350% by weight, breathing will increase, which is not preferable. The foaming agent used in the present invention can be a commercially available surfactant, for example, a known foaming agent such as an aromatic hydrocarbon or a sulfonate-based foaming agent, with air bubbles homogeneously dispersed in the filler. generate. To generate proper air bubbles, use 0.4 to 0.7 parts by weight per 100 parts by weight of cement. Next, as a water reducing agent, an AE water reducing agent such as an anionic type or a nonionic type is used. The AE water reducing agent has excellent foaming properties, increases the fluidity of the filler, and contributes to the strength of the filled part through its water reducing effect. cement
If it is less than 0.2 parts by weight per 100 parts by weight, the water-reducing effect will be small, and if it exceeds 0.3 parts by weight, the strength of the filled part will be reduced, so 0.2 to 0.3 parts by weight is appropriate. A viscosity agent is then added to increase the material separation resistance of the filler. As the viscous agent, a cold water-soluble polymeric admixture (methyl cellulose) is suitable, which is a white, tasteless, odorless, stable, and physiologically harmless powder made from purified cellulose, or pulp, and contains methylcellulose in its molecule. Methoxy group (-OCH ₃ ) from 27 to
One containing 32% by weight is suitable. Those with a methoxy group content within this range are most soluble in water. When the above-mentioned viscosity agent is added to the filler, it binds to the water in the cement paste and not only increases the viscosity of the cement paste itself, but also prevents upward separation of free water in the cement paste, that is, breathing. The amount of viscosity agent added is such that the water/cement ratio is 250 to 350.
In order to compensate for the decrease in material separation resistance due to the decrease in viscosity due to the addition of water in a proportion such as % by weight, the amount is set at 0.4 to 0.6 parts by weight per 100 parts by weight of cement. If it is less than 0.4 parts by weight, the viscosity improving effect will be reduced. If it exceeds 0.6 parts by weight, the viscosity will become too high, so it is not possible. The method for preparing the cavity filler of the present invention is to prepare a slurry by mixing particle size-adjusted granulated slag, ordinary Portland cement, and additives such as a foaming agent, water reducing agent, and viscosity agent with a predetermined amount of water. This is done by thoroughly kneading the ingredients. If a forced kneading mixer is used as the kneading equipment, a predetermined cavity filling material can be easily prepared. The cavity filling material preparation method of the present invention provides the following effects. (1) Compared to conventional cavity filling materials, the amount of cement is 1/3
Only a small amount of ~1/5 is required, and the filling material can be applied at low cost. (2) Filler preparation work is simple and quality control is easy. (3) The prepared filler has good workability, is lightweight, has little breathing, has appropriate fluidity, does not cause material separation, and is highly reliable. It is also significantly cheaper than conventional cavity fillers, and can be used as artificial lightweight earth and sand for backfilling back of seawalls to reduce earth pressure. Example 1 Mortar was prepared according to the basic formulation shown in Table 1. As the foaming agent, water reducing agent, and viscosity agent, an aromatic hydrocarbon foaming agent, an anionic AE water reducing agent, and a polymeric viscosity agent (methyl cellulose) were used, respectively.

[Table] The mortar produced according to the formulation shown in Table 1 was tested in accordance with JIS, and the results were as follows. Flow value: 210-260 mm 1 week compressive strength: 3-7 Kg/cm ² Air-dried unit volume weight: 1100-1250 Kg/m ³ Solidification time: Starting 15.00-18.00 Ending 20.00-24.00 Example 2 Using the particle-size-adjusted slag and the same foaming agent, water-reducing agent, and viscosity agent as in Example 1, the cavity filler of the present invention was prepared using the formulation shown in Table 3 in a 50-kneading forced mixer, aiming at a flow value of 200 to 220 mm. Preparation was carried out. The results are shown in Table 4. The coarse grain ratios shown in Table 2 are 80, 40, 20,
When a sieving test (JISA1102) was performed using a set of 5, 2.5, 1.2, 0.6, 0.3, and 0.15 mm mesh sieves, the sum of the mass percentages of all samples that did not pass through each sieve was divided by 100. It is a value.

【table】

【table】

[Table] Tables 3 and 4 show that by reducing the water/cement ratio and increasing the amount of slag, the flow value (fluidity) decreases, and the viscosity increases, which increases the air entrainment ability. It can be seen that the compressive strength decreases. Example 3 Using the same soft granulated slag as raw material and changing the crushing conditions of the crusher, the slag in Table 5 and the same foaming agent, water reducing agent, and viscosity agent as in Example 1 were used to produce the slag in Table 6. Example 2 of the cavity filler of the present invention under compounding conditions
Prepared in the same mixer. The results are shown in Table 7. In Table 5, the actual rate refers to the percentage of the absolute volume of aggregate filled in a container to the volume of that container,
The test method is specified in JISA1104 (Test method for aggregate unit volume weight and performance rate). Moreover, the coarse particle ratio is the same as that explained in Table 2.

【table】

【table】

[Table] Comparing Table 7 with Table 4, it is clear that water/
The reason why the compressive strength is increased despite the high cement ratio is because the particle size of the granulated slag is small, 0.149
This is because the amount of fine powder of mm or less is increasing. Furthermore, when the particle size of the granulated slag is small and the amount of fine powder increases, the flow value decreases and the amount of air increases. No.3
The reason why the compressive strength is higher in No. 4 despite having a larger amount of air is due to the increase in strength due to the increase in the amount of fine powder in the granulated slag rather than the decrease in strength due to the increase in the amount of air. This is thought to be the result of overshooting.

[Brief explanation of drawings]

FIG. 1 is a graph showing the degree of crushing when soft granulated slags having different unit volume weights are crushed under the same crusher conditions.

Claims (1)

[Claims] 1. Maximum particle size: 2.380 mm Amount passing through a 1.190 mm sieve is 95% or more Amount passing through a 0.590 mm sieve 70% or more Amount passing through a 0.279 mm sieve 40% or more Amount passing through a 0.149 mm sieve 15% or more Soft granulated slag with particle size adjustment 360~410,
Unit cement amount: 95~125Kg, water/cement ratio: 250~
A foaming agent, water reducing agent,
and viscosity agent, 0.4 to 0.7 parts by weight, 0.2 to 0.3 parts by weight, and 0.4 to 0.4 parts by weight, respectively, per 100 parts by weight of cement.
Add 0.6 parts by weight and stir to adjust the volume ratio of air to 25-30.
A method for preparing a cavity filling material, comprising preparing a lightweight foam filling material containing %.