JP2009084146A - Hardening material of molten slag and production method for hardened product of molten slag using the same hardening material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hardening material of molten slag, which can provide a hardened product of molten slag by kneading with water and an alkali stimulant, suppressing the hardened product from lowering of strength with passing of time; and to provide a production method for the hardened product using the hardening material. <P>SOLUTION: The hardening material contains pulverized molten slag, a fine aggregate and coal ash. Wherein, when a prescribed amount, exemplified by 100 pts.mass, of the molten slag in the hardening material is formulated with the fine aggregate by the prescribed ratio, a part of the aggregate can be replaced with the prescribed ratio of the coal ash without affection on the product. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a molten slag hardened material obtained from municipal waste incineration ash and a method for producing a molten slag hardened body using the same.

  Currently, the amount of general waste discharged in Japan is about 50 million tons per year, which means that 1 kg of garbage is discharged per person per day. Until recently, most of these municipal wastes were incinerated and landfilled. However, it was found that incineration ash contains harmful substances such as dioxins, and now, in order to remove these harmful substances, the incineration ash generated by incineration of waste is melted at a higher temperature. It is obliged to take.

  The incinerated ash that has been melted is rapidly cooled with cooling water, converted into molten slag (granulated slag), and then disposed of in landfills. On the other hand, effective utilization of molten slag is being studied because it is expected that it will be difficult to secure a landfill in the future. Currently, the use of molten slag that has been studied includes the use as fine aggregate for concrete and the use as roadbed material. Considering the increasing amount of general waste, municipal solid waste incineration ash A stable utilization method of molten slag obtained from the above is desired.

Therefore, the present applicants have previously proposed a molten slag hardened material made of fine powder of molten slag (see Patent Document 1). This molten slag hardener does not harden simply by mixing water, but can be used as a substitute for cement because it hardens by including water and an alkali stimulant.
JP-A-2005-60189

  However, as a result of further investigations on the molten slag hardened material of Patent Document 1, the present inventors have found that the molten slag hardened material obtained by kneading and curing the molten slag hardened material with water and an alkali stimulating material is an initial product. Although the strength is sufficient, it was found that the strength decreases with age.

  An object of the present invention is to provide a molten slag hardened material capable of suppressing a decrease in strength over time of a molten slag hardened body obtained by kneading with water and an alkali stimulating material, and a method for producing a molten slag hardened body using the same. It is to provide.

The molten slag hardener of the present invention that solves the above-mentioned problems is characterized by containing a pulverized molten slag, fine aggregate, and coal ash.
And the manufacturing method of the fusion slag hardening object of the present invention which solves the above-mentioned subject knead the molten slag hardening material containing the pulverized material of the fusion slag, the alkali stimulating material, the fine aggregate, and the coal ash, and water, The obtained kneaded product is cured by high temperature curing.

  According to the present invention, there is provided a molten slag hardened material which suppresses a decrease in strength over time of a molten slag hardened body obtained by kneading with water and an alkali stimulating material, and a method for producing a molten slag hardened body using the same. Can do.

Below, embodiment of the manufacturing method of the molten slag hardening material of this invention and a molten slag hardening body using this is described in detail. Here, after explaining a molten slag hardening material first, the manufacturing method of a molten slag hardening body is demonstrated.
The molten slag hardening material according to the present embodiment includes a pulverized product of molten slag, fine aggregate, coal ash, and an alkali stimulating material.

(Molten slag)
The molten slag in the present embodiment is a vitreous material obtained from incineration ash (general waste incineration ash) of general waste discharged from the urban living environment, and is referred to as general waste molten slag It is.
This molten slag can be obtained by melting municipal waste incineration ash at a high temperature of 1300 ° C. or higher, preferably 1400 ° C. or higher to remove dioxins, and then rapidly cooling the melt in water. This molten slag is also called granulated slag by being pulverized into granules when the municipal waste incineration ash melt is quenched.

This molten slag is mainly composed of SiO ₂ , Al ₂ O ₃ , and CaO, and the composition may vary depending on the melting method. For example, 38.3 mass% of SiO ₂ and CaO Examples include 36.1% by mass, Al ₂ O ₃ 14.9% by mass, Fe ₂ O ₃ 2.3% by mass, and Na ₂ O 1.3% by mass.
And the molten slag contains crystallization energy by making it amorphous, and has latent hydraulic property. That is, the molten slag is not cured by simply mixing water, but is cured by including water and an alkali stimulating material described later. Therefore, the molten slag in the present embodiment functions as a binding material that combines components such as other fine aggregates.

The average particle size (median diameter) of such molten slag is preferably 1 to 30 μm. The molten slag having such an average particle diameter may be obtained by further pulverizing the above-described granulated slag with a predetermined pulverizer.
Incidentally, a molten slag hardened material containing a molten slag having an average particle size (median diameter) of 1 μm or more can prevent re-aggregation of the molten slag in the molten slag hardened material, and has a process of further refinement. It becomes unnecessary, and the manufacturing cost of the molten slag hardened material can be reduced. Moreover, the molten slag hardening | curing material containing molten slag whose average particle diameter (median diameter) is 30 micrometers or less can make the compression strength of the molten slag hardening body obtained favorable.

(Fine aggregate)
Examples of the fine aggregate include river sand, sea sand, and crushed sand.
The content of the fine aggregate in the molten slag hardener is preferably set so as to satisfy the following relational expression (1).

1.77 ≦ V2 / V1 ≦ 2.10 (1)
(However, in said Formula (1), V1 represents the volume of the said molten slag contained in the said molten slag hardening material, and V2 represents the volume of the said fine aggregate contained in the said molten slag hardening material).
The volumes V1 and V2 here are converted from mass based on the density of each powder measured according to JIS R 5201 (cement physical test method).

  The fine aggregate in the molten slag hardener is preferably about 200 parts by mass in terms of mass, for example, with respect to 100 parts by weight of the molten slag hardener. In addition, the ratio by the mass conversion of the fine aggregate with respect to this molten slag can also be changed as long as the subject of this invention is not inhibited according to the property of the molten slag and fine aggregate to be used.

(Coal ash)
Coal ash is obtained in Japan as dust generated by coal combustion mainly from coal-fired power plants. Examples of the coal ash include fly ash, cylinder fly ash, clinker fly ash, and the like. Such coal ash is mainly composed of SiO ₂ and Al ₂ O ₃ , and there may be a difference in composition depending on the production area (component) of coal. , SiO ₂ 57.5% by mass, Al ₂ O ₃ 27.7% by mass, Fe ₂ O ₃ 5.4% by mass, and Na ₂ O 0.6% by mass.

The content of coal ash in the molten slag hardener is preferably set so as to satisfy the following relational expression (2).
0.05 ≦ V3 / (V2 + V3) ≦ 0.20 (2)
(However, in said Formula (2), V2 is synonymous with V2 in said Formula (1), and V3 represents the volume of the said coal ash contained in the said molten slag hardening material).

V3 / (V2 + V3) in the formula (2) is determined so that the blending amount of coal ash is replaced so as to replace a part of the fine aggregate contained in a predetermined amount with respect to the molten slag in the molten slag hardened material. In this case, it corresponds to the substitution rate converted by their volume. Hereinafter, “100 × V3 / (V2 + V3)” may be referred to as “coal ash replacement percentage (%)”.
Therefore, the molten slag hardening material of the present invention can be rephrased as a coal ash substitution percentage (%) of 5% or more and 20% or less.
In addition, the volume V3 here is converted from mass based on the density of the powder measured based on JISR5201 (the physical test method of cement).

(Alkali stimulant)
Examples of the alkali stimulating material in the present embodiment include anhydrous metasilicate, water glass, sodium hydroxide, calcium hydroxide and the like. An alkali stimulating material may be used independently and may mix and use 2 or more types. Among them, anhydrous sodium metasilicate and sodium hydroxide are desirable because it is easy to improve and handle the hydraulic properties of the molten slag and can increase the compressive strength of the resulting molten slag cured body. desirable.

  As for the compounding quantity of the alkali stimulating material in a molten slag hardening material, it is desirable to set it as 10 mass parts or more with respect to 100 mass parts of molten slag. And the compression strength of the molten slag hardened body tends to increase as the ratio (AL / SL) of the blending amount AL of the alkali stimulating material to the blending amount SL of the molten slag increases. The blending amount of the alkali stimulating material is more preferably 10 parts by mass or more and 35 parts by mass or less.

  The molten slag hardening material according to the present embodiment can be manufactured by blending the above-described molten slag, fine aggregate, coal ash, and alkali stimulating material in predetermined amounts and mixing them. Moreover, the molten slag hardening material may further contain a coarse aggregate.

Next, the manufacturing method of the molten slag hardening body using the molten slag hardening material which concerns on this embodiment is demonstrated.
This manufacturing method includes the above-described molten slag pulverized product, alkali stimulating material, fine aggregate, and coal ash in the above-described predetermined blending amount, and a molten slag hardener preparation step and the obtained molten slag hardening A kneading step of adding water to the material and kneading; and a curing step of curing the obtained kneaded material at a high temperature.

  In the preparation step, as described above, a molten slag pulverized product, an alkali stimulant, fine aggregate, and coal ash are blended in a predetermined blending amount, and these are kneaded to prepare a molten slag hardener. Is done.

The amount of water added to the molten slag hardened material in the kneading step may be about 50 parts by weight with respect to 100 parts by weight of the molten slag hardened material.
The kneaded product obtained in this kneading step may be blended with coarse aggregate in addition to alkali stimulating material, fine aggregate, coal ash, and water. What is necessary is just to set the compounding quantity of this coarse aggregate so that the volume of a coarse aggregate may be set to about 0.45 when the sum total volume (mortar volume) of a molten slag hardening material and water is set to 1. In addition, you may mix | blend a coarse aggregate with the molten slag hardening material before adding water.

  In the curing step, the molten slag hardened material that generates heat when water is added is kept warm, and the kneaded material containing the molten slag hardened material and water is cured at a high temperature by heating as necessary. Here, “high temperature curing” refers to curing of a cement-based mixed material at a high temperature, and refers to a known high-temperature curing that can quickly develop strength when the cement-based mixed material is cured. Specifically, the high temperature curing is performed at a temperature of 40 to 150 ° C., and preferably at 65 ° C. Such high temperature curing may be performed using a steam curing method, a sealed curing method, or the like. And the compressive strength of a molten slag hardening body will increase by such high temperature curing.

Next, the effect of the manufacturing method of the molten slag hardening material and molten slag hardening body which concerns on this embodiment is demonstrated.
According to the molten slag hardened material according to the present embodiment, since it is configured to include molten slag, fine aggregate, and coal ash, the time-lapse of the molten slag hardened body obtained by kneading together with water and an alkali stimulant. A decrease in strength can be suppressed.

  Moreover, since the molten slag hardened material according to the present embodiment includes molten slag, fine aggregate, and coal ash, the amount of shrinkage with time is small, and the generation of voids and the like is prevented even after aging. can do. And such an effect appears more notably by mix | blending molten slag, fine aggregate, and coal ash so that the said Formula (1) and (2) may be satisfied.

  The molten slag hardened material containing molten slag, fine aggregate, and coal ash at such a blending ratio is, for example, predetermined with respect to the molten slag contained in a predetermined amount of 100 parts by mass in the molten slag hardened material. When the fine aggregate is blended within the range of the ratio, it is equal to a part of the fine aggregate replaced with coal ash at a predetermined ratio.

Further, according to the molten slag cured material according to the present embodiment, the CO ₂ which has a large amount of discharge when firing the limestone in the manufacture of conventional cements generating a CaCO ₃ → CaO + CO ₂ by molten slag cement Substituting can be significantly reduced. That, CO ₂ generated by the combustion of the case as used coal to CO ₂ and firing caused by firing of limestone, cement per ton, from approximately 850 kg, molten slag cured material according to the present embodiment, the cement Instead, by replacing molten slag derived from municipal waste with cement raw material, it is possible to greatly reduce the emission of greenhouse gases that have a significant impact on the global environment.

  Moreover, in the molten slag hardening material according to the present embodiment, when natural sand is used as the fine aggregate, since coal ash that is industrial waste is used instead of natural sand that is a natural resource, According to this molten slag hardening material, the depletion of natural resources can be prevented.

The molten slag hardener of the present invention will be described more specifically with reference to examples.
Example 1
<Preparation of molten slag hardener>
In Example 1, first, the average particle size (median diameter) is about 13 μm and the specific gravity is 2 by pulverizing the molten slag (city waste molten slag) obtained from the general waste in the shaft type gasification melting furnace. A molten slag having a specific surface area of 3750 cm ² / g was obtained.

Next, 75.1 mL of fine aggregate and 4.0 mL of coal ash are blended with 35.7 mL of this molten slag, so that V2 / V1 of the equation (1) is 2.10, A composition in which V3 / (V2 + V3) of 2) was 0.05 was prepared. That is, this composition has the above-mentioned percentage of coal ash replacement of 5%.
The fine aggregate used here was crushed sand from Iwase, the specific gravity was 2.53, and the coarse particle ratio (FM) was 2.83. Further, the coal ash was JIS ash (type II) having a specific gravity of 2.20 and a specific surface area of 3460 cm ² / g.

  In such a composition, anhydrous sodium metasilicate as an alkali stimulant is blended so as to be 20 parts by mass with respect to 100 parts by mass of molten slag, and these are kneaded with a mortar mixer for 1 minute. An inventive molten slag hardener was prepared. Incidentally, this molten slag hardener consists of 190 parts by mass of fine aggregate, 8.8 parts by mass of coal ash, and 20 parts by mass of alkali stimulating material with respect to 100 parts by mass of molten slag. Hereinafter, this molten slag hardener is referred to as a molten slag hardener with a coal ash substitution percentage of 5%.

<Manufacture of molten slag hardened body (mortar)>
First, water was blended in the obtained molten slag hardener, and these were kneaded (main kneaded) for 1 minute 30 seconds with a mortar mixer. The compounding quantity of water was set so that it might be 50 mass parts with respect to 100 mass parts of molten slag. The flow value of the kneaded product (fresh mortar) was measured according to JIS R 5201 (cement physical test method). The result is shown in FIG. FIG. 1 is a graph showing the flow value of a kneaded product (fresh mortar) in which water is mixed and kneaded with a molten slag hardener, the horizontal axis is the percentage of coal ash substitution (%), and the vertical axis is the flow value. (Mm).

  Next, this kneaded material was packed into two layers in a bottomed cylindrical frame having a diameter of 50 mm and a depth of 100 mm. At this time, each layer was smoothed about 15 times so that its surface was flattened. And the steam curing was given to the kneaded material packed in the frame. As a result, a molten slag hardened material was obtained by curing the molten slag hardened material within the frame. By the way, steam curing was performed at 30 ° C. for 2 hours, and then the temperature was raised to 15 ° C./min up to a maximum temperature of 65 ° C. and stored at the same temperature for 5 hours.

  This molten slag hardened body was preserve | saved by the constant temperature / humidity method of 20 +/- 1 degreeC and 60 +/- 5% RH until the predetermined age (day) mentioned later. And the compressive strength of the molten slag hardened body is a predetermined age (day), that is, one day after the above steam curing is defined as material age 1 day, material age 1 day, material age 7 day , Measured on the 28th day of age, and on the 91st day of age. The compressive strength was measured according to JIS A 1108. The result is shown in FIG. FIG. 2 is a graph showing the relationship of the compressive strength (MPa) to the age (day) of the molten slag hardened body (mortar). In FIG. 2, (%) in parentheses is the percentage of coal ash replacement.

  Then, when the compressive strength on the first day of age is 1, the ratio of compressive strength after the lapse of a predetermined age (day) is shown in FIG. 3 as the compressive strength ratio. FIG. 3 is a graph showing the compressive strength ratio of the cured slag cured body on the 28th day and the 91st day.

  In Example 1, the shrinkage amount (μm) of the cured slag hardened body (mortar) after the lapse of a predetermined age (day) after the steam curing described above was measured. The result is shown in FIG. FIG. 4 is a graph showing the contraction amount (μm) of the cured slag hardened body (mortar) after the lapse of a predetermined age (day).

(Example 2)
<Preparation of molten slag hardener>
In Example 2, by adding 71.2 mL of fine aggregate and 7.9 mL of coal ash to 35.7 mL of molten slag, V2 / V1 of the formula (1) is 1.99, A composition having V3 / (V2 + V3) of formula (2) of 0.10 was prepared. That is, this composition has the above-mentioned percentage of coal ash substitution of 10%. The molten slag, fine aggregate, and coal ash used here are the same as those in Example 1.

  The blending amounts of molten slag, fine aggregate and coal ash were the same as in Example 1 except that V2 / V1 was set to 1.99 and V3 / (V2 + V3) was set to 0.10. Thus, the molten slag curing material of the present invention was prepared. Incidentally, this molten slag hardener consists of 180 parts by mass of fine aggregate, 17.4 parts by mass of coal ash, and 20 parts by mass of alkali stimulating material with respect to 100 parts by mass of molten slag. Hereinafter, this molten slag hardened material is referred to as a molten slag hardened material having a coal ash substitution percentage of 10%.

<Manufacture of molten slag hardened body (mortar)>
A molten slag hardened body was produced in the same manner as in Example 1 except that the molten slag hardened material obtained in Example 2 was used. Under the present circumstances, it carried out similarly to Example 1, and measured the flow value of the kneaded material of molten slag hardening | curing material and water. The result is shown in FIG.
The compressive strength of the obtained molten slag cured body was measured in the same manner as in Example 1. The result is shown in FIG.
Moreover, the compression strength ratio in the age 28th day and the material age 91st day of a molten slag hardening body is shown in FIG.
Moreover, the shrinkage | contraction amount (micrometer) of the molten slag hardening body after progress of predetermined | prescribed age (day) was measured similarly to Example 1. FIG. The result is shown in FIG.

(Example 3)
<Preparation of molten slag hardener>
In Example 3, 67.2 mL of fine aggregate and 11.9 mL of coal ash are blended with 35.7 mL of molten slag so that V2 / V1 of the formula (1) is 1.88, A composition having V3 / (V2 + V3) of formula (2) of 0.15 was prepared. That is, this composition has the above-mentioned coal ash substitution percentage of 15%. The molten slag, fine aggregate, and coal ash used here are the same as those in Example 1.

  The blending amounts of molten slag, fine aggregate and coal ash were the same as in Example 1 except that V2 / V1 was set to 1.88 and V3 / (V2 + V3) was set to 0.15. Thus, the molten slag curing material of the present invention was prepared. Incidentally, this molten slag hardener consists of 170 parts by mass of fine aggregate, 26.2 parts by mass of coal ash, and 20 parts by mass of the alkali stimulating material with respect to 100 parts by mass of molten slag. Hereinafter, this molten slag hardener is referred to as a molten slag hardener with a coal ash substitution percentage of 15%.

<Manufacture of molten slag hardened body (mortar)>
A molten slag hardened body was produced in the same manner as in Example 1 except that the molten slag hardened material obtained in Example 3 was used. Under the present circumstances, it carried out similarly to Example 1, and measured the flow value of the kneaded material of molten slag hardening | curing material and water. The result is shown in FIG.
The compressive strength of the obtained molten slag cured body was measured in the same manner as in Example 1. The result is shown in FIG.
Moreover, the compression strength ratio in the age 28th day and the material age 91st day of a molten slag hardening body is shown in FIG.
Moreover, the shrinkage | contraction amount (micrometer) of the molten slag hardening body after progress of predetermined | prescribed age (day) was measured similarly to Example 1. FIG. The result is shown in FIG.

Example 4
<Preparation of molten slag hardener>
In Example 4, 63.3 mL of fine aggregate and 15.8 mL of coal ash are blended with 35.7 mL of molten slag so that V2 / V1 of the formula (1) is 1.77, A composition having V3 / (V2 + V3) of the formula (2) of 0.20 was prepared. That is, this composition has the above-mentioned coal ash substitution percentage of 20%. The molten slag, fine aggregate, and coal ash used here are the same as those in Example 1.

  The blending amounts of molten slag, fine aggregate, and coal ash were the same as in Example 1 except that V2 / V1 was set to 1.77 and V3 / (V2 + V3) was set to 0.20. Thus, the molten slag curing material of the present invention was prepared. Incidentally, this molten slag hardener consists of 160 parts by mass of fine aggregate, 34.8 parts by mass of coal ash, and 20 parts by mass of alkali stimulating material with respect to 100 parts by mass of molten slag. Hereinafter, this molten slag hardener is referred to as a molten slag hardener with a coal ash substitution percentage of 20%.

<Manufacture of molten slag hardened body (mortar)>
A molten slag cured body was produced in the same manner as in Example 1 except that the molten slag cured material obtained in Example 4 was used. Under the present circumstances, it carried out similarly to Example 1, and measured the flow value of the kneaded material of molten slag hardening | curing material and water. The result is shown in FIG.
The compressive strength of the obtained molten slag cured body was measured in the same manner as in Example 1. The result is shown in FIG.

  Moreover, the compression strength ratio in the age 28th day and the material age 91st day of a molten slag hardening body is shown in FIG. And the compression strength ratio in the material age 1st day, material age 7th day, material age 14th day, and material age 28th day of a molten slag hardening body is shown in FIG. FIG. 5 is a graph showing the relationship between the age (days) of the molten slag hardened body obtained in Example 4 and the compression strength ratio. And in FIG. 5, the compression strength ratio of the molten slag hardening body of the reference example mentioned later is written together.

  Moreover, the shrinkage | contraction amount (micrometer) of the molten slag hardening body after progress of predetermined | prescribed age (day) was measured similarly to Example 1. FIG. The result is shown in FIG.

  6A is a photomicrograph of a cured slag cured material of the first day of age obtained in Example 4 by a scanning electron microscope (SEM), and FIG. 6B is obtained in Example 4. FIG. It is a microscope picture by the scanning electron microscope (SEM) of the molten slag hardened | cured material of the 91st day of age.

(Comparative Example 1)
<Preparation of molten slag hardener>
In Comparative Example 1, 79.1 mL of fine aggregate is blended with 35.7 mL of molten slag, and coal ash is not blended. Thus, V2 / V1 of the formula (1) is 2.22, and the formula A composition in which V3 / (V2 + V3) of (2) was “0” was prepared. In other words, this composition has the above-described percentage of coal ash substitution of 0%. The molten slag and fine aggregate used here are the same as those in Example 1.

  Then, the present invention was carried out in the same manner as in Example 1 except that the blending amounts of molten slag and fine aggregate were set so that V2 / V1 was 2.22 and V3 / (V2 + V3) was “0”. A molten slag hardener was prepared. Incidentally, this molten slag hardener consists of 200 parts by mass of fine aggregate, 0 parts by mass of coal ash, and 20 parts by mass of alkali stimulating material with respect to 100 parts by mass of molten slag. Hereinafter, this molten slag hardener is referred to as a molten slag hardener with a coal ash substitution percentage of 0%.

<Manufacture of molten slag hardened body (mortar)>
A molten slag hardened body was produced in the same manner as in Example 1 except that the molten slag hardened material obtained in Comparative Example 1 was used. Under the present circumstances, it carried out similarly to Example 1, and measured the flow value of the kneaded material of molten slag hardening | curing material and water. The result is shown in FIG.

The compressive strength of the obtained molten slag cured body was measured in the same manner as in Example 1. The result is shown in FIG.
Moreover, the compression strength ratio in the age 28th day and the material age 91st day of a molten slag hardening body is shown in FIG.
Moreover, the shrinkage | contraction amount (micrometer) of the molten slag hardening body after progress of predetermined | prescribed age (day) was measured similarly to Example 1. FIG. The result is shown in FIG.
FIG. 7A is a photomicrograph obtained by scanning electron microscope (SEM) of the cured slag cured material of the first day of age obtained in Comparative Example 1, and FIG. 7B is obtained in Comparative Example 1. It is a microscope picture by the scanning electron microscope (SEM) of the molten slag hardened | cured material of material age 91st.

(Evaluation of the molten slag hardener obtained in Examples 1 to 4 and Comparative Example 1)
As shown in FIG. 2, the compression strength of the molten slag hardened body (coal ash substitution percentage 0%) manufactured using the molten slag hardened material of Comparative Example 1 starts to decrease from the 7th day of material age.
On the other hand, the molten slag hardened body manufactured from the molten slag hardened material of Example 1 (percentage of coal ash replacement 5%) maintains good compressive strength even after the 7th day of material age. .
And in Example 2, Example 3 and Example 4 with a coal ash substitution percentage of 10% or more, the compressive strength is further increased from the seventh day of age, contrary to Comparative Example 1.

  Moreover, as shown in FIG. 3, the compression strength ratio of the molten slag hardened body (mortar) is 1. for the molten slag hardened body in Comparative Example 1 (coal ash substitution percentage 0%) at the age of 28 days. Below 0. On the other hand, as for the molten slag hardened | cured material in Example 1- Example 4 whose coal ash substitution percentage is 5% or more, all of the compressive strength ratio of material age 28th day and material age 91st day are " It is far above 1.0 ”. In Comparative Example 1, the compressive strength ratio at the age of 91 days is lower than the compressive strength ratio at the age of 28 days, whereas in Examples 1 to 4, the opposite is true. Further, the compressive strength ratio at the age of 91 days is improved from the compressive strength ratio at the age of 28 days.

  Moreover, as shown in FIG. 4, the shrinkage | contraction amount of the molten slag hardened | cured material (mortar) is small with the increase in the coal ash substitution percentage. That is, the molten slag cured body in Examples 1 to 4 having a coal ash substitution percentage of 5% or more has a smaller shrinkage than the molten slag cured body of Comparative Example 1, and thus the volume is easily stabilized. Generation of cracks in the body can be prevented.

  On the other hand, as shown in FIG. 1, the flow value of fresh mortar tends to decrease as the percentage of coal ash replacement increases. That is, considering workability at the time of kneading fresh mortar, it is desirable that the coal ash replacement percentage at which the flow value is about 180 mm is 20% (Example 4).

Moreover, as shown to Fig.7 (a), although the molten slag hardening body (coal ash substitution percentage 0%) in the comparative example 1 has not produced defects, such as a space | gap, on the 1st day of age, FIG. As shown in (b), defects such as voids are produced at the age of 91 days.
On the other hand, as shown in FIGS. 6 (a) and 6 (b), the molten slag hardened body in Example 4 (coal ash substitution percentage 20%) is the first day of material age and the 91st day of material age. In any case, defects such as voids are not generated.

  As apparent from the above Examples 1 to 4 and Comparative Example 1, the molten slag hardened material of the present invention contains molten slag, fine aggregate, and coal ash, so that the obtained molten slag was obtained. It was verified that a decrease in strength over time of the cured body can be suppressed.

Further, since the molten slag hardened material of the present invention contains molten slag, fine aggregate, and coal ash, the amount of shrinkage with time is small, and the generation of voids and the like is prevented even after aging. It was confirmed that
And it was confirmed that such an effect appears more remarkably in Example 1 to Example 4 where V2 / V1 and V3 / (V2 + V3) described above satisfy the expressions (1) and (2). . In addition, V2 / V1 and V3 / (V2 + V3) in Examples 1 to 4 and Comparative Example 1 are collectively shown in the following Table 1.

  However, in Table 1, V1 represents the volume of the molten slag contained in the molten slag hardened material, V2 represents the volume of the fine aggregate contained in the molten slag hardened material, and V3 is contained in the molten slag hardened material. Represents the volume of coal ash.

  And as shown in FIG. 5, the molten slag hardened | cured material obtained from the molten slag hardened material (V2 / V1 is 1.77 and V3 / (V2 + V3) is 0.20) of Example 4 is a material. It is larger than the compressive strength ratio on the 28th day of age than the compressive strength ratio on the first day of age.

  On the other hand, the molten slag cured body of the reference example has a compressive strength ratio of about 1.0 from the first day of material age to the 28th day of material age. By the way, this reference example is obtained from a molten slag hardened material blended with molten slag, fine aggregate, and coal ash so that V2 / V1 is 2.77 and V3 / (V2 + V3) is 0.08. The molten slag hardened body is shown. More specifically, this molten slag hardened material is a part of this molten slag based on the molten slag hardened material in which 79.1 mL of fine aggregate is blended with 35.7 mL of molten slag of Comparative Example 1. 7.1 mL is replaced with coal ash, and includes 28.6 mL of molten slag, 79.1 mL of fine aggregate, and 7.1 mL of coal ash.

That is, in Example 4, 20% of fine aggregate was replaced with coal ash in volume conversion, whereas in Reference Example, 20% of molten slag was replaced with coal ash in volume conversion. is there.
Therefore, as shown in FIG. 5, even if the coal ash is contained in the same proportion in terms of volume, the fine aggregate is more coal ash than the molten slag hardened body (reference example) in which the molten slag is replaced with coal ash. It was verified that the molten slag cured body (Example 4) replaced with the above increased the compressive strength ratio with age.

(Example 5 to Example 8)
<Manufacture of molten slag hardened body (concrete)>
In Examples 5 to 8, fresh concrete was prepared by blending coarse aggregate with the mortar (fresh mortar obtained by adding water to a molten slag hardener) prepared in each of Examples 1 to 4. did. The blending amount of the coarse aggregate is set by volume ratio so that the coarse mortar prepared in each of Examples 1 to 4 is “1” and the coarse aggregate is “0.45”. did.

  The slump value in each of the obtained fresh concrete was measured according to JIS A 1101 (concrete slump test method). The result is shown in FIG. FIG. 8 is a graph showing a slump value of a kneaded material (concrete) obtained by mixing and kneading water and coarse aggregate with a molten slag hardened material, where the horizontal axis represents the percentage of coal ash substitution (%), and the vertical axis Represents the slump value (cm).

  Next, the fresh concrete obtained in Example 5 to Example 8 is injected into a bottomed cylindrical frame having a diameter of 50 mm and a depth of 100 mm, and then cured by steam curing to melt slag. It became a hardened body (concrete). Note that the steam curing was performed under the same conditions as in Example 1.

  And this molten slag hardening body was preserve | saved by the constant temperature / humidity method of 20 +/- 1 degreeC and 60 +/- 5% RH until the predetermined | prescribed age (day) mentioned later. The compressive strength of the molten slag hardened body was measured in the same manner as in Example 1. The result is shown in FIG. FIG. 9 is a graph showing the relationship of the compressive strength (MPa) to the age (days) of the molten slag hardened body (concrete). In addition, in FIG. 9, (%) in parentheses is the percentage of coal ash replacement.

  And the shrinkage | contraction amount (micrometer) of the molten slag hardened | cured material (concrete) after progress of predetermined | prescribed age (day) after the above-mentioned steam curing was measured. The result is shown in FIG. FIG. 10 is a graph showing the shrinkage (μm) of the molten slag hardened body (concrete) after the lapse of a predetermined age (day).

(Evaluation of the molten slag hardener obtained in Example 5 to Example 8)
As shown in FIG. 9, the molten slag hardened body manufactured using the molten slag hardened material of Examples 5 to 8 (coal ash replacement percentage 5% to 20%) is further increased from the seventh day of the material age. Compressive strength is increasing.

  Moreover, as shown in FIG. 10, the shrinkage | contraction amount of molten slag hardened | cured material (mortar) is small with the increase in the coal ash substitution percentage. That is, the molten slag hardened bodies (concrete) in Examples 5 to 8 having a coal ash substitution percentage of 5% or more have a relatively small shrinkage, and thus the volume is easily stabilized. Occurrence can be prevented.

  In addition, as shown in FIG. 8, it is verified that the slump value of fresh concrete is maintained in a good range even when the percentage of coal ash replacement increases, and the workability during mixing of fresh concrete is also improved. It was done.

(Example 9 to Example 12)
In Examples 9 to 12, instead of molten slag having an average particle diameter (median diameter) of about 13 μm, molten slag having an average particle diameter of 5 μm is used, and the alkali stimulating material shown in FIG. 11 is used. Except having used, similarly to Example 1, while preparing the molten slag hardening material, the molten slag hardening material (mortar) was manufactured using this molten slag hardening material. In each of the molten slag hardened bodies (mortar) produced in each example, the compressive strength at the age of 28 days was measured in the same manner as in Example 1. The result is shown in FIG. FIG. 11 is a graph showing the relationship between the type and the compressive strength of the obtained molten slag hardened body when the alkali stimulating material is water glass, anhydrous sodium metasilicate, sodium hydroxide, or calcium hydroxide. is there.

(Evaluation of the molten slag hardened material obtained in Examples 9 to 12)
As shown in FIG. 11, the molten slag hardened body using a molten slag hardener containing water glass, anhydrous sodium metasilicate, or sodium hydroxide as an alkali stimulant is far more than that using calcium hydroxide. It was verified that the compressive strength was excellent. And the molten slag hardening body (Example 10) which uses anhydrous sodium metasilicate was most excellent in compressive strength.

It is a graph which shows the flow value of the kneaded material (fresh mortar) which mix | blended water and knead | mixed the molten slag hardening material, a horizontal axis is a coal ash substitution percentage (%), and a vertical axis | shaft is a flow value (mm). is there. It is a graph which shows the relationship of the compressive strength (MPa) with respect to the age (day) of a molten slag hardening body (mortar). It is a graph which shows the compression strength ratio in the material age 28th day and the material age 91st day of a molten slag hardening body. It is a graph which shows the shrinkage | contraction amount (micrometer) of the molten slag hardening body (mortar) after progress of predetermined | prescribed material age (day). It is a graph which shows the relationship between the age (day) of a molten slag hardening body obtained in Example 4, and compression strength ratio. (A) is the microscope picture by the scanning electron microscope (SEM) of the molten slag hardened | cured material of the age 1st day obtained in Example 4, (b) is the material age 91 days obtained in Example 4. It is a microscope picture by the scanning electron microscope (SEM) of the molten slag hardening body of eyes. (A) is the microscope picture by the scanning electron microscope (SEM) of the molten slag hardened | cured material of the age 1st day obtained by the comparative example 1, (b) is the material age 91 days obtained by the comparative example 1. It is a microscope picture by the scanning electron microscope (SEM) of the molten slag hardening body of eyes. It is a graph which shows the slump value of the kneaded material (concrete) which mix | blended water and coarse aggregate with the molten slag hardening material, Comprising: A horizontal axis represents a coal ash substitution percentage (%), and a vertical axis | shaft is slump value ( cm). It is a graph which shows the relationship of the compressive strength (MPa) with respect to the age (day) of a molten slag hardening body (concrete). It is a graph which shows the shrinkage | contraction amount (micrometer) of the fusion | melting slag hardening body (concrete) after progress of predetermined | prescribed material age (day). When an alkali stimulating material is water glass, anhydrous sodium metasilicate, sodium hydroxide, or calcium hydroxide, it is a graph which shows the relationship between the kind and the compressive strength of the obtained molten slag hardening body.

Claims (6)

  A molten slag hardener comprising pulverized molten slag, fine aggregate, and coal ash. The molten slag hardener according to claim 1, wherein the molten slag, the fine aggregate, and the coal ash are included so as to satisfy the following relational expressions (1) and (2).
1.77 ≦ V2 / V1 ≦ 2.10 (1)
0.05 ≦ V3 / (V2 + V3) ≦ 0.20 (2)
(However, in said Formula (1) and (2), V1 represents the volume of the said molten slag contained in the said molten slag hardening material, and V2 is the volume of the said fine aggregate contained in the said molten slag hardening material. V3 represents the volume of the coal ash contained in the molten slag hardener)   2. The molten slag hardener according to claim 1, wherein an average particle size of the pulverized molten slag is 1 to 30 μm.   The molten slag hardening material according to claim 1, further comprising an alkali stimulant selected from the group consisting of anhydrous metasilicate, water glass and sodium hydroxide.   The molten slag hardening material according to claim 4, wherein the alkali stimulating material is anhydrous sodium metasilicate.   A molten slag characterized by kneading a molten slag hardened material containing molten slag, alkali stimulant, fine aggregate, and coal ash and water, and curing the obtained kneaded material at a high temperature. A method for producing a cured product.