JPH09241051A - Production of uncalcined aggregate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce the aggregate excellent in handling and strength developing and not needing separation according to the grain diameter by adding water to a powder consisting essentially of coal ash, granulating the powder, steam- curing the granulated material, then crushing a large-diameter grain and regulating the grain diameters in a specified range. SOLUTION: A raw powder consisting essentially of coal ash and further blended with a cement powder (e.g. ordinary Portland cement) and various additives such as silica fumes and gypsum, as required, is mixed with an appropriate amt. (ordinarily, 10-40wt.%) of water, and the mixture is granulated with a granulator. The content of coal ash in the raw powder is preferably controlled to 50-95wt.% and that of cement powder to 5-50wt.%. The granulated material is steam-cured at 60-85 deg.C for 5-20hr. The grain size of this aggregate is confirmed, and the grains are separated into the target grains having 5-20mm diameter and the grains having diameters beyond the range. The large-diameter grains are crushed by a crusher and used as sand having a small grain diameter. The ratio of the globular aggregate (the original) to deformed aggregate (crushed aggregate) is controlled to 2:8 to 8:2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a non-fired aggregate, and more particularly to a method for producing a non-fired aggregate which is excellent in handleability and strength development when mixed with concrete.

[0002]

2. Description of the Related Art Non-fired aggregates, that is, non-fired artificial aggregates can effectively utilize waste such as coal ash and can be manufactured at a lower cost than fired artificial aggregates.

Conventionally, non-calcined aggregate is prepared by mixing water with a powder consisting mainly of coal ash, granulating it with a pan-type granulator, etc., and steam curing the granulated product, and then adjusting the particle size. Being manufactured.

[0004]

Since the conventional non-fired aggregate obtained by granulation has a spherical shape, it has good fluidity when mixed into concrete (when fresh) when mixed into concrete. , It has the advantage that a small amount of water is sufficient to obtain the same slump,
It has the following disadvantages.

Rolls easily and has poor handleability.
Therefore, for example, it is difficult to convey the aggregate to a high position such as an aggregate yard or a hopper by a belt conveyor.
It is also difficult to pile up.

Since the surface of the aggregate is smooth, when it is mixed with concrete, the adhesion to the mortar portion is poor, which adversely affects the strength development of the concrete. Therefore, sufficient strength cannot be obtained.

Since it is easy to separate the particles by particle size, it may be necessary to store the particles by particle size. Further, in the manufacturing process of the non-fired aggregate, when the raw material is granulated, regardless of the performance of the bread-type granulator or the like used, granules are produced which are out of the target particle size range. Conventionally, a granulated product that is out of the target particle size range is discarded, or finely crushed and returned to the pan-type granulator and re-granulated as a part of the raw material.

The present invention solves the above-mentioned problems of the prior art, is excellent in handling property, is also excellent in strength development when mixed with concrete, and has a yield of a non-fired aggregate which does not cause a problem of separation according to particle size. The object is to provide a method of manufacturing well.

[0009]

According to a first aspect of the present invention, a non-calcined aggregate is produced by adding water to a powder mainly composed of coal ash to granulate it and then steam curing it. In the method described above, the steam-cured aggregate is separated into particles having a predetermined particle size range and particles having a larger particle size than the predetermined particle size range, and the large particle size is crushed. Along with this, the particles are sized in the predetermined particle size range, and then the sized particles are mixed with the particles in the predetermined particle size range.

The method for producing a non-fired aggregate according to claim 2 is a method for producing a non-fired aggregate by adding water to a powder mainly composed of coal ash and granulating the mixture, followed by steam curing. The subsequent aggregate is separated into a particle having a predetermined particle size range and a particle having a larger particle size than the predetermined particle size range, and a part of the particle having the predetermined particle size range is crushed. It is characterized in that the particles are sized in the predetermined particle size range and then the sized particles are mixed with the particle size in the predetermined particle size range.

The method for producing a non-fired aggregate according to claim 3 is a method for producing a non-fired aggregate by adding water to a powder containing coal ash as a main component, granulating the powder, and then producing a non-fired aggregate. The subsequent aggregate is separated into particles having a predetermined particle size range and particles having a larger particle size than the predetermined particle size range, and a part of the particle having the predetermined particle size range and the large particles are separated. It is characterized by crushing a particle having a diameter and sizing to a predetermined particle size range, and then mixing the sized particle with the particle having a predetermined particle size range.

Particles having a particle size larger than a predetermined particle size range and /
Alternatively, by crushing a part of the particles in a predetermined range, it is possible to obtain a deformed aggregate having a predetermined particle size and not spherical but having corners or distortion. This irregularly shaped aggregate is hard to roll and is therefore excellent in handleability. In addition, when mixed with concrete, the adhesion to the mortar part is improved, the strength development is excellent, and there is almost no separation by particle size.

Therefore, by mixing this irregularly shaped aggregate with the spherical aggregate having a predetermined particle size range, the advantage of the spherical aggregate, that is, the advantage that a small amount of water is sufficient to obtain the same slump, is sufficient. It is possible to obtain a non-calcined aggregate that has the advantages of the deformed aggregate, that is, the handling properties and the strength development of concrete are excellent, and the advantages that it is difficult to separate by particle size.

Since the aggregate is artificial and is uniform from the surface to the inside, crushing hardly changes the properties of the aggregate.

In the first and third aspects of the invention, since the particles having a particle size larger than the target predetermined particle size range are crushed and mixed and used, the particles outside the predetermined particle size range may be discarded. The yield and production efficiency are improved as compared with the conventional method of re-granulating.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.

In the present invention, first, coal ash is mainly used, cement-based powder (for example, ordinary Portland cement, blast furnace cement, fly ash cement, etc.) and, if necessary, various additives such as silica fume and gypsum. An appropriate amount (10 to 40% by weight with respect to the raw material powder) of water is mixed with the raw material powder blended with, and the mixture is granulated according to a conventional method using a pan-type granulator or the like.

The amount of coal ash in this raw material powder was 50.
~ 95 wt%, especially 70-90 wt% is preferred.

The cement-based powder is preferably the above-mentioned ordinary Portland cement, early-strength Portland cement, blast furnace cement or fly ash cement. The proportion of the cement-based powder in the raw material powder is 5 to 50% by weight,
Especially, 10 to 30% by weight is preferable.

The obtained granulated product is preferably 60 to 80 ° C.
Then, steam curing is performed for about 5 to 20 hours to obtain an aggregate.

The grain size of the aggregate is confirmed, and the aggregate is divided into a grain component within a predetermined target grain size range and a grain component outside the target grain size range.

Particles having a particle size larger than a predetermined particle size range and /
Alternatively, after crushing a predetermined range of particles with a crusher, sizing (for example, sieving) within a predetermined particle size range is performed to obtain a modified aggregate.

Then, this irregularly shaped aggregate is mixed with the particles within the predetermined particle size range, and the particle size is adjusted as necessary to obtain a product.

Particles having a particle size smaller than a predetermined particle size range are used as sand.

The above-mentioned predetermined particle size range is arbitrarily set according to the purpose of use of the non-calcined aggregate obtained, etc., but in the usual case, it is in the range of 5 to 20 mm, or 5 to 15 mm.

Further, a spherical aggregate having a predetermined particle size range,
The mixing ratio with the crushed irregularly-shaped aggregate can also be arbitrarily set according to the purpose of use of the non-calcined aggregate, but in order to sufficiently obtain the mixing effect of the irregularly-shaped aggregate according to the present invention, a predetermined particle size range The mixing ratio of the spherical aggregate and the crushed irregularly shaped aggregate is
Spherical aggregate: deformed aggregate = 2: 8 to 8: 2 (weight ratio) is preferable.

[0027]

The present invention will be described more specifically below with reference to examples and comparative examples.

Examples 1 to 3 (Examples of the invention of claim 1) To a mixture of 80 parts by weight of coal ash and 20 parts by weight of cement, 30 parts by weight of water was added and mixed, and this was a pan type. Granulated with a granulator. The obtained granulated product was steam-cured at 80 ° C. for 10 hours to obtain an aggregate. This aggregate has a particle size of 5 to 15 m
m particles (spherical aggregate) and particles having a particle size of more than 15 mm are separated.
After crushing with a crusher, the particles were sized to obtain irregularly shaped aggregate having a particle size of 5 to 15 mm.

The spherical aggregate and the irregularly shaped aggregate were mixed in the proportions shown in Table 1 to obtain the non-fired aggregate of the present invention.

Using the non-fired aggregate obtained, concrete was kneaded under the following mixing conditions (without using an admixture):
The compressive strength was measured at 28 and 91 days old, and the results are shown in Table 1. The amount of kneading water used to obtain the following slump value is also shown in Table 1.

Mixing conditions Water cement ratio (W / C) = 40% Fine aggregate ratio (s / a) = 40% Slump = 8 ± 1 cm Comparative Example 1 Only the spherical aggregate obtained in Example 1 was used. Other than the above, concrete was kneaded in the same manner, and Table 1 shows the kneading water amount for obtaining the compressive strength and the same slump value for each material age.

Comparative Example 2 Concrete was kneaded in the same manner except that only the deformed aggregate obtained in Example 1 was used, and the amount of kneading water for obtaining the compressive strength and the same slump value at each age is shown in Table 1. It was shown to.

Example 4 (Example of the Invention of Claim 2) In Example 1, a part of the particle size of 5 to 15 mm was crushed and then sized to obtain a modified aggregate having a particle size of 5 to 15 mm. 75 parts by weight of spherical particles of 5 to 15 mm and 5 to 5 parts of this irregular shape
25 parts by weight of 15 mm aggregate was mixed to obtain a non-sintered aggregate of the present invention.

Using this non-fired aggregate, concrete was kneaded under the same conditions as in Example 1 and the compressive strength was measured. The results are shown in Table 1.

Embodiment 5 (Embodiment of the Invention of Claim 3) In Embodiment 1, a part of the particles of 5 to 15 mm is crushed and then sized to obtain a modified aggregate A having a particle diameter of 5 to 15 mm. .
Further, the irregular aggregate B having a particle diameter of 5 to 15 mm was obtained by crushing the particles having a particle diameter of more than 15 mm and sizing. Spherical 5
A non-sintered aggregate of the invention of claim 3 was obtained by mixing 50 parts by weight of 15 mm particles, 25 parts by weight of this modified aggregate A and 25 parts by weight of modified aggregate B.

Using this non-fired aggregate, concrete was kneaded under the same conditions as in Example 1 and the compressive strength was measured. The results are shown in Table 1.

[0037]

[Table 1]

The following is clear from Table 1.

When only spherical aggregates were used (Comparative Example 1), the amount of kneading water for obtaining the same slump value was small,
Poor strength development. On the other hand, when only the deformed aggregate is used (Comparative Example 2), the strength development is excellent, but the amount of kneading water for obtaining the same slump value is large. As described above, the one requiring a large amount of kneading water has a drawback that the shrinkage tends to increase.

On the other hand, according to the example of the present invention in which the spherical aggregate and the irregularly shaped aggregate are mixed, the amount of kneading water is relatively small and the strength development is excellent.

[0041]

As described in detail above, according to the method for producing a non-fired aggregate of the present invention, the handling property is excellent, the strength development when mixed in concrete is also excellent, and the separation according to particle size is performed. It is possible to manufacture a non-calcined aggregate with no problem of high yield.

Therefore, by using the non-calcined aggregate produced by the present invention, it is possible to produce concrete having high strength and excellent uniformity with good workability.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kenya Suganuma 4-6-14 Shibaura, Minato-ku, Tokyo Inside TEPCO Environmental Engineering Co., Ltd.

Claims (3)

[Claims] 1. A method for producing a non-calcined aggregate by steam-curing after adding water to a powder mainly composed of coal ash and granulating the powder, wherein the steam-cured aggregate has a predetermined particle size range. A particle and a particle having a particle size larger than the predetermined particle size range are separated, and the particle having the large particle size is crushed and sized in the predetermined particle size range;
Next, a method for producing a non-calcined aggregate characterized in that the sized particles are mixed with the particles having a predetermined particle size range. 2. A method for producing non-calcined aggregate by steam curing after adding water to a powder consisting mainly of coal ash and granulating the powder, wherein the aggregate after steam curing has a predetermined particle size range. Particles and particles having a particle size larger than the predetermined particle size range are separated, and a part of the particles in the predetermined particle size range is crushed and sized to the predetermined particle size range, Next, a method for producing a non-calcined aggregate characterized in that the sized particles are mixed with the particles having a predetermined particle size range. 3. A method for producing a non-calcined aggregate by steam curing after adding water to a powder mainly composed of coal ash and granulating the powder, wherein the aggregate after steam curing has a predetermined particle size range. The particles are separated into particles having a particle size larger than the predetermined particle size range, and a part of the particles having the particle size range and the large particles are crushed and A method for producing a non-calcined aggregate, which comprises sizing to a particle size range of 1, and then mixing the sized particles with a particle size in the predetermined particle size range.