JPH08259290A - Production of lightweight aggregate - Google Patents

Abstract

PURPOSE: To improve productivity by kneading synthetic resin foams, water and a hydraulic binder, then pelletizing the mixture by using a pan type pelletizing machine, thereby forming lightweight aggregate of a required size. CONSTITUTION: The synthetic resin foams of PS resin, etc., having an average grain size of about 0.1 to 2.0mm and sp. gr. of about 0.02 to 0.2, the hydraulic binder, such as Portland cement and the water of 10 to 30wt.% of the binder and if necessary, various additives, such as AE agent and water-reducing agent, are kneaded by a mixer. The kneaded matter is then supplied into an inclined pan 2 of the pan type pelletizing machine 1 which is disposed freely vibratably on a bed 4 and is arranged at an inclination angle of 30 to 60 deg. with the horizontal direction. The water is sprayed at need by a water sprayer 5 and the pan is rotated at a number of revolutions of 1 to 100rpm. The pellets 6 grown to a prescribed size in about 30 to 120 seconds of stagnation time are transported by a transporting belt 7. The hydraulic binder C is added to these pellets with a water sprayer 8 to coat the pellets with the binder and hot air H is blown to the pellets by a dryer 8, by which the pellets are dried and the lightweight aggregate is obtd.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lightweight concrete aggregate for mixing into lightweight concrete, raw materials such as heat insulating material, sound absorbing material, sound insulating material, fire resistant material, ground (improved) material, and soil (improved material). ) It relates to a method for producing a lightweight aggregate used as a material.

[0002]

2. Description of the Related Art Lightweight concrete has come to be used in various fields.
As shown in SA5002, artificial lightweight aggregates such as expanded shale, expanded clay, expanded slate, and fired fly ash, natural lightweight aggregates such as volcanic gravel and its processed products, by-product lightweight aggregates such as expanded slag, and These products are classified as by-product lightweight aggregates.

Further, recently, synthetic resin foam beads are directly mixed to obtain lightweight concrete, or, for example, as shown in Japanese Patent Publication No. 54-11814, foam synthetic resin moldings are obtained by crushing. For example, lightweight concrete is obtained by mixing a mixture of hydraulic binder such as cement on the surface of the granular material.

However, the lightweight aggregate shown in JIS has a lot of voids in the aggregate, so that it is inferior in watertightness and freeze-thaw resistance, and also has a high water absorption rate, resulting in a large drying shrinkage rate. There is. Also, in the case of lightweight concrete with synthetic resin foam beads mixed as it is, synthetic resin foam beads have strong water repellency and extremely low specific gravity, so lack of affinity with cement paste, and before the cement hardens, the synthetic resin There is a problem in that the foam beads rise and it is difficult to obtain uniform concrete. Furthermore, in the case of lightweight concrete using lightweight aggregate in which a hydraulic binder is bonded to the surface of synthetic resin foam beads, etc., a uniform thickness is obtained on the surface of the synthetic resin foam beads of this lightweight aggregate. It is difficult to coat the hydraulic binder, and therefore, the specific gravity and strength of the lightweight aggregate tend to vary, and as a result, the quality of the lightweight concrete using the same deteriorates.

Therefore, the inventor of the present invention has developed a lightweight concrete aggregate in which a plurality of synthetic resin foams are solidified by a hydraulic binder such as cement to be integrated, and the applicant of the present application has filed a patent application for the contents. (Japanese Patent Application No. 6-71031).
According to this lightweight concrete aggregate, since a plurality of synthetic resin foams are solidified and integrated with a hydraulic binder, compared to the case where one synthetic resin foam is coated with a hydraulic binder, The thickness of the coating of the hydraulic binder on the synthetic resin foam is kept substantially uniform, which has the advantage that variations in specific gravity and strength can be reduced.

In this case, the synthetic resin foam is beaded,
That is, if it is spherical or substantially spherical, both weight and volume of the synthetic resin foam beads can be easily measured, variation in the measurement can be suppressed to a small extent, and further, a granular product obtained by crushing the synthetic resin molded product can be obtained. In comparison, stress dispersion is good, and an aggregate with high strength can be obtained. Further, if the overall shape of the lightweight concrete aggregate is made substantially spherical, the fluidity of the concrete is improved when the aggregate is mixed with the concrete and is poured on site.

By the way, a method for industrially mass-producing a lightweight concrete aggregate obtained by solidifying a plurality of synthetic resin foam beads or the like as described above with a hydraulic binder and molding them into a preferably spherical shape. However, for example, synthetic resin foam is kneaded with water and a hydraulic binder, extruded into a strip or string with an extruder, or cut into small pieces of the required size, or It is conceivable to manufacture the lightweight concrete aggregate by shaping it into a granular shape.

[0008]

However, according to the manufacturing method, the kneaded material containing the synthetic resin foam is extruded and then cut or shaped, so that the number of manufacturing steps increases,
Not only is it difficult to obtain sufficient productivity, but there is also a problem that the manufacturing apparatus including an extruder, a cutter, a shaping machine and the like becomes complicated.

Furthermore, when a small piece obtained by simply cutting a kneaded product extruded in a band shape or a string shape is used as an aggregate, it is difficult to form the small piece into a spherical shape or a substantially spherical shape. Has a problem in that it lowers the fluidity of the concrete and eventually lowers the workability when pouring concrete. Therefore, it is also considered to perform the shaping finish so as to form a substantially spherical shape by rolling the aggregate composed of the small pieces in the rotary cylinder, but in that case, the number of man-hours is further increased and the manufacturing apparatus is complicated. In addition to the above-mentioned tendency, it is difficult to finish the lightweight concrete aggregate into a shape close to a sphere even by the shaping finish.

[0010]

The present invention is a method for producing a lightweight aggregate used as a lightweight concrete aggregate or the like, which solves the above-mentioned problems, and which has a small number of steps and a high productivity. The purpose is to provide. Therefore, in the method for manufacturing a lightweight aggregate according to claim 1, a synthetic resin foam, water and a hydraulic binder are granulated using a pan-type granulator to produce a lightweight aggregate having a required size. It is characterized by doing.

According to such a manufacturing method, a synthetic resin foam,
Water and hydraulic binder are fed into the pan (granulation dish) of the pan granulator and the pan is rotated at a predetermined speed. As a result, the synthetic resin foam and the hydraulic binder are agitated and flowed in the pan due to the frictional resistance generated between the synthetic resin foam and the bottom wall of the pan, and the hydraulic binder is hydrated with water. Kneading is carried out while causing a reaction. Further, when the rotation of the bread is continued, the hydraulic binder grows into particles while taking in a plurality of synthetic resin foams, and is granulated into a required size to form a lightweight aggregate.

As described above, since the granulation can be performed only by supplying the synthetic resin foam, water and the hydraulic binder into the pan of the pan-type granulator and rotating them, the above-mentioned extrusion step and cutting or shaping step can be performed. It is possible to reduce the number of manufacturing steps of the lightweight aggregate and to improve the productivity, as compared with the manufacturing method including. Further, as the manufacturing apparatus, only the pan type granulator may be used, so that the manufacturing apparatus can be simplified. Further, by rotating in a pan, so as to perform the granulation, the granulated lightweight aggregate has a shape closer to a sphere, as compared with the one cut into small pieces of a predetermined size after the extrusion, Therefore, for example, when the lightweight concrete aggregate is mixed into the concrete, the fluidity of the concrete is also improved.

According to a second aspect of the present invention, there is provided a method for producing a lightweight aggregate, which comprises kneading a synthetic resin foam, water and a hydraulic binder and then supplying the kneaded mixture to a pan-type granulator and granulating using the pan-type granulator. The present invention is characterized in that it is granulated to produce a lightweight aggregate having a required size.

According to such a manufacturing method, water and a hydraulic binder are added to the synthetic resin foam, and the kneaded product previously kneaded by a mixer or the like is inserted into the pan of the bread granulator and rotated. As a result, the kneaded product is agitated and flown in the pan due to the frictional resistance between the kneaded product and the bottom wall of the pan, and along with this, the hydraulic binder grows into particles while incorporating a plurality of synthetic resin foams. Then, granulation is performed in the required size. Here, since the kneaded product obtained by kneading in advance was granulated by further rotating it with a pan-type granulator, the synthetic resin foam, water and the hydraulic binder were individually pan-formed. Compared to the case of supplying to the granulator and granulating, granulation is performed more smoothly, and the size and shape of the granulated product are more easily aligned, therefore,
The quality of the lightweight aggregate produced by granulation is further improved.
Further, the time required for granulation is shortened and the productivity is good as compared with the case where the synthetic resin foam, water and the hydraulic binder are individually supplied to the pan-type granulator for granulation.

A method for manufacturing a lightweight aggregate according to a third aspect is the method for manufacturing a lightweight aggregate according to the first or second aspect, wherein the mixing ratio (W / C) of the hydraulic binder (C) and water (W) is 1 by weight
It is characterized by being set to 0 to 30%.

That is, when the mixing ratio (W / C) of water (W) to the hydraulic binder (C) is set to 10 to 30% by weight, it is possible to granulate in a suitable size. According to the manufacturing method of claim 1, for example, the hydraulic binder (C) and water (W) are individually supplied to the pan-type granulator, and the granulation is performed subsequent to the kneading in the pan-type granulator. But
The mixing ratio (W / C) in this case is a weight ratio of the hydraulic binder (C) and water (W) supplied to the pan granulator,
On the other hand, when the mixture is kneaded with a mixer or the like before being supplied to the bread granulator, the mixing ratio (W / C) is the mixing ratio in the mixer or the like.

If the mixing ratio is less than 10%, the hydration reaction of the hydraulic binder will be insufficient, and the hardening of the hydraulic binder will not be sufficiently promoted. Become. On the other hand, when the mixing ratio exceeds 30%, the surface water of the granulated product increases, and the lightweight aggregates granulated to a predetermined size have a strong tendency to be bonded to each other to generate huge particles.
The particle size becomes excessively large, which is not preferable.

The method for producing a lightweight aggregate according to claim 4 is characterized in that, in the method for producing a lightweight aggregate according to claim 3, water is added during granulation by a pan-type granulator to obtain a lightweight aggregate having a predetermined size. To do.

According to this manufacturing method, when the kneaded product is granulated by the pan-type granulator, water is added by a method such as spraying, so that the granulation is promoted and the lightweight aggregate having a predetermined size is obtained. Is easily obtained. That is, when the synthetic resin foam, water and the hydraulic binder have been already kneaded when kneading, due to the passage of time until granulation, the binding property of the hydraulic binder is somewhat reduced, so that, Granulation may not proceed smoothly. Therefore, water is added at the time of granulation to cause a hydration reaction in the unreacted portion of the hydraulic binder to enhance the bondability of the hydraulic binder and accelerate granulation. In the manufacturing method of claim 1, the pan-type granulator is supplied with the synthetic resin foam, water and a hydraulic binder, and is rotated to carry out the granulation subsequent to the kneading. In this case, granulation can be promoted by continuously adding water in the granulation stage.

According to a fifth aspect of the present invention, there is provided the method for producing a lightweight aggregate according to the first or second aspect, wherein the mixing ratio of the hydraulic binder and water is 18 to 25% by weight. It is a feature.

That is, the present inventor further restricts the range of the mixing ratio in claim 3 to 18 to 25% so that the addition of water during granulation as in claim 4 is not performed. We have found that it can be smoothly granulated. When water is added during granulation, the lightweight aggregate to be granulated tends to adhere to the surface of the bread, and it tends to be difficult to continuously granulate for a long time, but the mixing ratio is 18 to 25%. If,
Since the granulation can be performed smoothly without special means such as adding water at the time of granulation, the problem that the lightweight aggregate adheres to the surface of the bread hardly occurs, and continuous granulation for a long time becomes possible. The particle size of the granulated lightweight aggregate can be adjusted by increasing or decreasing the mixing ratio within the above range, and the particle size gradually increases as the mixing ratio increases within the above range. The particle size of the lightweight aggregate is not particularly limited, but is, for example, 2.5 to 15 m.
The range is about m. The more preferable range of the mixing ratio within the range of 18 to 25% is 20 to 23%.

The method for producing a lightweight aggregate according to claim 6 is the method for producing a lightweight aggregate according to any one of claims 1 to 5, wherein the lightweight aggregate is coated with a hydraulic binder after granulation. It is characterized by preventing the adherence of.

Thus, by coating the lightweight aggregate with the hydraulic binder after granulation, the strength of the lightweight aggregate can be increased by the hydraulic binder coated on the outer surface of the lightweight aggregate. The coated hydraulic binder suppresses the joining of lightweight aggregates, making it difficult for giant particles to be generated.
preferable.

According to a seventh aspect of the present invention, there is provided a method for producing a lightweight aggregate according to any one of the first to fifth aspects, wherein the lightweight aggregate is blown with hot air after the granulation to dry the aggregate. It is characterized by preventing adhesion. That is, by blowing hot air to the lightweight aggregate after the granulation to quickly remove water on the surface, the lightweight aggregates are unlikely to adhere to each other.

The method of manufacturing a lightweight aggregate according to claim 8 is the method of manufacturing a lightweight aggregate according to any one of claims 1 to 5, wherein the lightweight aggregates are moved to each other 2 to 24 hours after granulation. It is characterized by preventing adhesion of lightweight aggregates.

That is, after a lapse of a predetermined time after the granulation, the granule is moved by, for example, vibrating, dropping an inclined place, or giving an impact to the granule,
By moving by rotating, dropping, etc., it is possible to effectively prevent the adhesion and joining of the lightweight aggregates without special means such as coating the lightweight aggregate with the hydraulic binder as in claim 6. Was found. In this way, by preventing the adhesion of the lightweight aggregates by moving each other, for example, as compared with the case of covering the lightweight aggregate with a hydraulic binder, it becomes easier to manage the specific gravity, Productivity is also improved. It should be noted that the time period during which the mutual movement is performed is 2 to 24 hours after the granulation,
By the time the surface of the granulated lightweight aggregate is dried, in other words, until there is no water adhering to the surface of the lightweight aggregate, or until the adjacent lightweight aggregates are firmly joined together, Since it takes about 2 to 24 hours, by moving the lightweight aggregates next to each other during this time,
This is because the adhesion of the lightweight aggregates can be effectively prevented.

The method for producing a lightweight aggregate according to claim 9 is the method for producing a lightweight aggregate according to any one of claims 1 to 5, wherein the lightweight aggregate is sieved about 2 to 24 hours after granulation. It is characterized in that the lightweight aggregates are prevented from adhering to each other.

Also in this case, for example, compared with the case where the surface of the lightweight aggregate is coated with a hydraulic binder,
The control of the specific gravity of the lightweight aggregate is facilitated and the productivity is improved. The sieving as described above is one of the most effective and rational means as one means for moving in claim 8.

A method of manufacturing a lightweight aggregate according to claim 10 is
The manufacturing method according to any one of claims 1 to 9, wherein the lightweight aggregate is added with water after granulation and hardening to increase the strength.

According to such a manufacturing method, since the lightweight aggregate is added with water after the granulation and hardening, the strength of the lightweight aggregate can be improved. As a method of adding water, for example, when performing curing after granulation and curing, in air curing,
Prior to this aerial curing, water can be added by a method such as water sprinkling.On the other hand, when the curing is performed by underwater curing, steam curing, autoclave curing, etc., the lightweight aggregate is immersed in water or steam during curing. By doing so, water is added during curing.

A method of manufacturing a lightweight aggregate according to claim 11 is
The manufacturing method according to any one of claims 1 to 10, wherein the rotation speed of the pan-type granulator during granulation is 1 to 100 rpm.

That is, the rotation speed of the pan granulator is 1r.
If it is less than pm, it takes time to granulate, and giant particles are easily generated, and granulation with a suitable particle size tends to be difficult. On the other hand, when the rotation speed of the bread granulator exceeds 100 rpm, the synthetic resin foam kneaded with water and the hydraulic binder tends to separate from the hydraulic binder, resulting in the synthesis in the lightweight aggregate. Since the number of resin foams tends to be insufficient, for example, when such a lightweight aggregate is mixed into concrete, the problem that the specific gravity of the concrete product becomes large tends to occur. The suitable rotation speed changes depending on the diameter of the bread, and it is preferable that the smaller the diameter of the bread, the higher the rotation speed.

A method of manufacturing a lightweight aggregate according to claim 12 is:
The manufacturing method according to any one of claims 1 to 11, wherein the inclination angle of the pan-type granulator during granulation is 30 to 60 °.

That is, when a kneaded product made of synthetic resin foam, water and a hydraulic binder is inserted into an inclined pan of a pan type granulator and rotated, as described above, the kneaded product is mainly Due to the frictional resistance between the bread and the inclined bottom wall, the bread is agitated and fluidized in the area near the lower end of the bread to be granulated. If the inclination angle of the shaft with respect to the horizontal direction) is less than 30 °, the frictional resistance between the bottom wall of the pan and the kneaded product tends to be small, and the stirring efficiency of the kneaded product tends to be low, so that a smooth manufacturing Grain tends to be difficult. On the other hand, when the inclination angle of the bread granulator exceeds 60 °, the kneaded material stirred in the bread is dispersed not only in the vicinity of the lower end of the inclined bread but also in almost the entire area of the bottom wall of the bread. As a result of stirring and stirring, the stirring region tends to spread too much, and smooth granulation tends to be difficult. Therefore, the inclination angle of the pan granulator is preferably in the range of 30 ° to 60 °, more preferably in the range of 40 ° to 50 °,
Most preferred is around 45 °.

A method for manufacturing a lightweight aggregate according to claim 13 is:
The manufacturing method according to any one of claims 1 to 12, wherein the lightweight aggregate is lightweight concrete aggregate. By mixing the lightweight aggregate into concrete, the weight of the concrete can be reduced, and the lightweight concrete aggregate can be easily manufactured by a pan-type granulator.

[0036]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. This embodiment relates to a method for manufacturing a lightweight concrete aggregate as a lightweight aggregate. As shown in FIG. 3, a plurality of synthetic resin foams are solidified with a hydraulic binder such as cement to be integrated. In manufacturing the lightweight concrete aggregate, the synthetic resin foam was kneaded by adding water and a hydraulic binder, and then granulated using a pan granulator 1 as shown in FIGS. 1 and 2. It is granulated to produce lightweight concrete aggregate of the required size.

The synthetic resin foam contained in the lightweight concrete aggregate may be a crushed product obtained by crushing a synthetic resin foam or an irregular shape, but is not limited to a spherical or substantially spherical so-called bead. In this case, the weight and volume measurement errors are small, and the variations in specific gravity of individual lightweight concrete aggregates are small, so that a product of stable quality can be obtained. Also, for concrete products using this,
If stress is applied, it can be dispersed if it is a bead, and a concrete product with high strength can be obtained, but in the case of crushed products or irregular shapes, stress concentration is applied,
Since the strength is weakened, beads are preferable as much as possible.

Whether the synthetic resin foam is a crushed product, an irregular shape or a bead, the average diameter thereof is 0.1 to 2.
The range is 0 mm, more preferably 0.1 to 1.5 mm. If it is less than 0.1 mm, it becomes too small, and when kneading with water and a hydraulic binder, the fluidity of the kneaded product tends to decrease and the amount of synthetic resin foam cannot be increased. It is difficult to reduce the weight of the concrete products. Further, if the average diameter is 2.0 mm or more, the number of synthetic resin foams that can be contained in one aggregate is limited, and the strength tends to be weak, which is not preferable. The average diameter when the synthetic resin foam is a crushed product or has a different shape is expressed as an average value of the maximum length and the minimum length.

The synthetic resin used as the raw material for the synthetic resin foam is a styrene resin such as polystyrene, an olefin resin such as polypropylene or polyethylene, an acrylonitrile-styrene copolymer or a styrene-ethylene copolymer. Polymer (of course, random, block,
(Including grafts), polyvinyl chloride, polyvinylidene chloride, and other vinyl chloride resins, etc.
Among these, when polystyrene is used, the strength is high,
It is the most desirable because it is cheap.

The true specific gravity of the synthetic resin foam, that is, the specific gravity before kneading with the hydraulic binder is 0.02 to 0.2.
The range of is good. If it is less than 0.02, the strength tends to be low, and the shape of the aggregate tends to be deformed during kneading with the hydraulic binder, so that the strength as an aggregate tends to be low. On the other hand, if the synthetic resin foam has a true specific gravity of 0.2 or more, the strength of the synthetic resin foam is almost the same as that of the raw material cost, but it is uneconomical. The ones are suitable. It is not appropriate to describe this in terms of the expansion ratio because it depends on the type of raw material, etc., but it is generally in the range of 5 to 50 times, and the particularly preferred expansion ratio is in the range of 10 to 30 times. is there.

Examples of hydraulic binders for hardening a plurality of synthetic resin foams include cement, lime and gypsum.
Of these, cement has high strength and excellent water resistance,
It is also the most desirable because it is relatively inexpensive. As the cement, blast furnace cement, silica cement, fly ash cement, and the like can be used in addition to ordinary Portland cement, early-strength Portland cement, and the like, and it is preferable to use them properly depending on the application.

Mixing ratio of water to hydraulic binder (W /
If C) exceeds 30%, not only the water absorption is large, the expansion coefficient due to water absorption is large, and the strength is low,
At the time of granulation after kneading, granules tend to be bonded to each other to easily generate giant particles. On the other hand, if the mixing ratio (W / C) is less than 10%, the hydration reaction of the hydraulic binder does not proceed sufficiently, and smooth granulation tends to be difficult to perform during granulation after kneading. Since it has, the mixing ratio (W / C) is 10 by weight.
The range of 30% to 30% is preferable. In addition, the mixing ratio (W / C) in this case is a pan-type granulator when a synthetic resin foam, water, and a hydraulic binder are individually supplied to the pan-type granulator 1 described later for granulation. It means the weight ratio of water to be supplied to the machine 1 and the hydraulic binder, and the synthetic resin foam, water and the hydraulic binder are pre-kneaded with a mixer or the like, and then supplied to the pan granulator 1 for granulation. When granulating, it means the mixing ratio of water and the hydraulic binder in the mixer or the like.

The bread-type granulator 1 used for granulation in this example is conventionally used for granulating fertilizer, ceramics, processed mineral products, etc., and is shown in FIGS. 1 and 2. As described above, basically, the electric motor, the reduction gear, and the like (not shown) are built in, and the rotation drive unit 3 that rotationally drives the pan 2 is swingably provided on the base 4. The pan 2 is composed of a circular bottom wall 2a and an annular side wall 2b rising from the peripheral edge of the bottom wall 2a at a right angle to the bottom wall 2a.

At the time of granulation, the synthetic resin foam, water and a hydraulic binder are individually supplied into the pan 2 of the pan-type granulator 1, and the synthetic resin foam, water and water are rotated by rotating the pan 2. After kneading the hard binder, it is possible to granulate to a required size by subsequently stirring and mixing the kneaded product. However, more preferably, the synthetic resin foam, water and hydraulic binder is supplied into a conventional concrete mixer such as a pan-type mixer (not shown), an omni mixer, a twin-screw forced kneading mixer, etc., at this time, if necessary, After kneading the synthetic resin foam, water and a hydraulic binder while mixing various admixtures such as an AE agent and a water reducing agent, the kneaded product is supplied into the pan 2 of the pan-type granulator 1 to form bread. By rotating 2 the granulation is carried out in the required size.

The mixing amount of the various admixtures is preferably about 0.1 to 1.0% in weight ratio with respect to the hydraulic binder, since it is easy to mix, and by mixing such admixtures. The strength of lightweight concrete aggregate can be increased by about 10%. Further, if sand or the like is mixed in with the admixture, the strength of the lightweight concrete aggregate can be further improved. When kneading in the concrete mixer, a so-called lump may occur in the mixer. In that case, in order to crush the lump and perform smooth kneading, a roller or the like is used. It is preferably attached to a mixer.

When the mixture is kneaded in advance with a mixer or the like and granulated with the pan granulator 1, the granules can be easily aligned in size and shape, and the quality of the lightweight concrete aggregate obtained by granulation is improved. In addition to being able to do so, the time required for granulation in the pan-type granulator 1 can be shortened by kneading in advance, so that productivity can be improved.

The rotational drive speed of the pan 2 by the rotary drive unit 3 during granulation is preferably in the range of 1 to 100 rpm (rotation / minute). That is, the rotation speed of the pan 2 is 1r
If it is less than pm, the granulation time tends to be long, and the surface water of the granulated product is large, so that there is a problem that large particles are easily generated. On the other hand, the rotation speed of the pan 2 is 100 rp
When it exceeds m, the synthetic resin foam kneaded with water and the hydraulic binder easily separates from the hydraulic binder, and as a result, the number of synthetic resin foams in the granulated product tends to be insufficient, and When granules are used as concrete aggregate, it tends to be difficult to achieve sufficient weight reduction of concrete products.

The rotational drive speed is preferably increased / decreased within the range of 1 to 100 rpm according to the diameter of the pan 2, and the rotational drive speed is preferably increased as the diameter of the pan 2 is smaller. That is, the bread 2 has a diameter of 0.
When it is 5 m, the rotational drive speed is preferably in the range of 50 to 70 rpm (most preferably about 60 rpm), and when the diameter of the pan 2 is 1.0 m, the rotational drive speed is 25 to 35 rpm.
Is preferable (most preferably about 30 rpm), and when the diameter of the pan 2 is 3.0 m, the rotational driving speed is 8 to 12
A range of rpm is preferred (most preferably about 10 rp
m).

The inclination angle A of the bread 2 with respect to the horizontal direction during granulation by the rotation of the bread 2 is preferably in the range of 30 to 60 °. That is, when a kneaded product made of a synthetic resin foam, water and a hydraulic binder is inserted into the pan 2 and rotated, the kneaded product mainly causes friction between the slanted bottom wall 2a of the pan 2. Due to the resistance, the mixture is agitated and flowed in the vicinity of the lower end of the pan 2, and the hydraulic binder is granulated while growing into particles while taking in the synthetic resin foam, but the inclination angle A of the pan 2 is If it is less than 30 °, the frictional resistance between the bottom wall 2a and the kneaded material becomes small, and the stirring efficiency of the kneaded material tends to decrease,
Smooth granulation tends to be difficult. On the other hand, when the inclination angle A of the bread 2 exceeds 60 °, the kneaded material stirred in the bread 2 is dispersed not only in the vicinity of the lower end of the inclined bread 2 but also in almost the entire area of the bottom wall 2a. As a result, the stirring area tends to be too wide and smooth granulation tends to be difficult. Therefore, the inclination angle A of the pan 2
Is preferably in the range of 30 ° to 60 °, and 40 °
More preferred is the range of 50 °, with about 45 ° being most preferred.

When the kneaded product of the synthetic resin foam, water and the hydraulic binder is inserted into the pan 2 and rotated at a predetermined rotation speed, the kneading is carried out near the lower end of the inclined pan 2 as described above. The material is fluidized and agitated, and the hydraulic binder forms particles while incorporating a plurality of synthetic resin foams,
Granulate to the required size. During this granulation, if water W or steam is supplied into the pan 2 by the water sprinkler 5 or the like, the newly supplied water W or steam reacts with the unreacted portion of the hydraulic binder. However, since the binding property of the hydraulic binder is improved, it has an effect of promoting granulation, which is preferable. However, water addition at the time of granulation is not essential. In addition,
When a hydraulic binder such as cement is likely to adhere to the bottom wall 2a of the bread 2 to form a coating layer, a scraping member (not shown) such as a scraper is provided in the bread granulator 1. be able to.

The granular granulated material 6 grown to the required size is
By the self-classifying action, the kneaded material at the lower end of the bread 2 floats near the surface of the kneaded material, and overflows from the upper end of the side wall 2b of the bread 2 to be sequentially discharged from the bread 2. At this time, the kneaded product obtained by kneading the synthetic resin foam, water and the hydraulic binder at a speed substantially equal to the discharging speed of the granulated product 6 is used for the pan 2
If the ingredients are sequentially fed into the inside, granulation by the bread 2 can be continuously performed. In the above description, the kneaded product previously kneaded with a mixer or the like is supplied to the pan 2.
Instead of this, an unkneaded synthetic resin foam and a hydraulic binder are supplied into the pan 2, and the kneading and granulation are continuously performed in the pan 2 while supplying water 5 or steam by spraying or the like. You may do it. When kneading and granulating are continuously performed in the pan 2, it is difficult to clearly distinguish kneading and granulation, but when only granulating is performed in the pan 2, when kneading and granulation are performed. In either case, the granulation time in the pan 2 is 3
0 to 120 seconds is preferable, and if the granulation time is less than 30 seconds, there is a tendency that sufficient granulation is not performed.
If it exceeds 0 seconds, the grain size tends to be too large.

The granulated material 6 discharged from the pan 2 is conveyed in a predetermined direction by, for example, a conveyor belt 7. It is possible to coat the outer surface of the granulated material 6 with the hydraulic binder C by a method such as spraying the hydraulic binder C on the granulated material 6, preferably on the granulated material 6 with the sprayer 8, on the conveyor belt 7. it can. As the hydraulic binder C for coating, a hydraulic binder of the same type as that used when kneading the synthetic resin foam and water, for example, cement may be used. By coating the hydraulic binder C, the coated hydraulic binder C reacts with the moisture on the surface to improve the strength of the granule 6, and the granule 6 is coated with the hydraulic binder C. It is preferable to suppress the joining of the particles with each other, and as a result, to suppress the generation of giant particles during the transportation by the transport belt 7.

The granulated material 6 coated with the hydraulic binder C is
Further, while being conveyed by the conveyor belt 7, drying is performed by blowing hot air H with the dryer 9 as needed. As described above, by rapidly drying the granules 6, adhesion of the granules 6 to each other is prevented. However, the effect of preventing the granules 6 from adhering to each other can be obtained only by one of the methods of coating with the hydraulic binder C and hot air drying described above. If the purpose is only to prevent adhesion, it is not always necessary to use both methods of coating the hydraulic binder C and hot air drying together. For example, when coating the hydraulic binder C, drying is simply natural. It may be dried.

The preferable temperature of the hot air H in the case of performing the above hot air drying varies depending on the carrying speed of the carrying belt 7 and the like, but is usually about 100 to 150 ° C. By performing hot air drying or natural drying as described above, the subsequent curing step can be shortened. It is preferable to dry only the vicinity of the surface of the granulated product 6, and if the interior is dried, it becomes difficult to adjust the shape of the granulated product 6 thereafter. However, if the granules 6 can be shaped into a spherical shape or a shape close to a substantially spherical shape only by granulation by the rotation of the bread 2, the granulated material 6 may be dried to the inside.

After completion of drying the granulated product 6, if necessary, by rolling the granulated product 6 in a rotary cylinder (not shown),
The granulated product 6 can be finished and shaped into a spherical shape or a substantially spherical shape. However, when the spherical or substantially spherical granulated product 6 can be produced only by the rotation by the pan 2, the finish shaping step is not essential. After completion of the drying step, or after completion of the finishing shaping step performed as necessary, it is preferable to add water once again by sprinkling the granulated material 6 to increase the strength. After the addition of water, the granulated product 6 is sent to a curing process (not shown) and cured by a method such as air curing. When a method such as underwater curing, steam curing, or autoclave curing is used as the curing method, since the granulated product 6 is immersed in water or steam during curing, the granulated product 6 is watered, It is not necessary to add water by a method such as watering before curing.

After the completion of the curing step, the granulated product 6 is screened if necessary and separated into a plurality of groups having different sizes. The lightweight aggregate thus produced can be used by being mixed with a hydraulic binder such as cement as shown in FIG. 4, and in this case, it is referred to as lightweight concrete aggregate. At this time, if necessary, fine aggregate such as sand or expanded synthetic resin beads may be mixed in addition to the lightweight concrete aggregate. Incidentally, as the hydraulic binder to mix lightweight concrete aggregate, lime, gypsum, etc. can be used in addition to cement, but in the present specification, for the sake of convenience even when mixed with lime, gypsum, etc., lightweight It is called concrete aggregate.

The size of the lightweight concrete aggregate may be appropriately adjusted according to the application and is not particularly limited, but for example, in the range of 2.5 to 45 mm, more preferably 2.5 to 15 mm. Can be or,
Although the number of synthetic resin foams contained in each lightweight concrete aggregate is not particularly limited, for example, when the diameter of the lightweight concrete aggregate is 10 mm and the average diameter of the synthetic resin foam is 0.7 mm, It is preferable that the number is about 50 to 250.

When a part of the synthetic resin foam is exposed from the outer peripheral surface of the lightweight concrete aggregate to the outer surface of the aggregate as shown in FIG. 3, when the concrete product is produced, cement or the like is used. Since the water absorption rate by the aggregate when mixed in the hydraulic binder becomes small, the quality of the water-cement ratio when kneading the lightweight concrete aggregate and the hydraulic binder such as cement is easy to manage and the quality is stable, Particularly preferred.

Next, another embodiment of the present invention will be described. As shown in FIG. 5, unlike the above-described embodiment, the lightweight concrete aggregate manufacturing apparatus according to this embodiment includes a water sprinkler 5 for supplying water W to the pan-type granulator 1 and a conveyor belt 7. A sprayer 8 and a dryer 9 for spraying the hydraulic binder C and spraying hot air H onto the granules 6 conveyed by
Is not provided.

Here, the range of the mixing ratio (W / C) of the hydraulic binder to water is 10 to 30% of that in the above embodiment.
The weight ratio is further limited to 18 to 25%, and more preferably 20 to 23%. According to the experiments of the present inventor, by limiting the mixing ratio to the range of 18 to 25%, smooth and good granulation can be performed without adding water to the pan 2 during granulation in the pan 2. It became clear that In that case, the kneaded product previously kneaded with a mixer or the like can be supplied to the pan 2 and only granulation can be performed in the pan 2.

As described above, if water is not added to the bread 2 during granulation, the granules 6 are prevented from adhering to the surface of the bread 2, so that the bread 2 can be continuously fed for a long time. This is preferable because it enables granulation.

Further, according to the experiments of the present inventor, after granulation,
By moving the granules 6 to each other by some means before and after the granules 6 start to harden, it is possible to prevent the granules 6 from joining and adhering to form huge particles. It was revealed. In addition, in the case of preventing the granules 6 from adhering to each other using a means for moving the granules 6 to each other, the hot air H is not necessarily applied to the granules 6 being conveyed by the conveyor belt 7.
It is not necessary to spray and force-dry, but normal natural drying is sufficient. In the case of performing such natural drying, the above-mentioned mutual movement is imparted after granulation in the pan 2 for about 2 to 24 hours, more preferably for about 2 to 10 hours,
More preferably, it is carried out after about 3 to 6 hours.

That is, before the surface of the granulated product 6 is dried, in other words, until the water adhering to the surface of the granulated product 6 disappears, or the adjacent granulated products 6 are firmly bonded together. Since it takes about 2 to 24 hours until this is done, the adhering of the granules 6 to each other can be effectively prevented by moving the granules 6 adjacent to each other during this time period.

As a method of giving mutual movement, a plurality of granules 6 are housed in a container such as a box and the containers are vibrated by a shaker or the like, or the granules 6 are conveyed by a conveyor belt 7. In the case of transporting, various methods such as dropping the granulated material 6 from the downstream end of the transport belt 7, dropping it at an inclined place, and applying an impact to the granulated material 6 can be used. As one of the means for imparting mutual movement to the granulated product 6, the granulated product 6 is sieved 2 to 24 hours after the granulation in the same manner as described above. You may make it prevent adhesion of 6 comrades. The size of the mesh of the sieve is the size of the granulated product 6 (for example, 2.5 to 15 mm)
It may be set appropriately according to the above.

As described above, when the granules 6 are prevented from adhering to each other by applying some vibration, impact or sieving as means for moving the granules 6 to each other, for example, a hydraulic binder C Compared with the case where the surface of the granulated product 6 is covered with, it becomes easier to control the specific gravity of the granulated product 6, that is, the lightweight concrete aggregate, and the sprinkler 8 and the dryer 9 are not required. There is an advantage that the device can be simplified and the productivity can be improved. The above-described operation of applying vibration or impact or sieving may be performed only once, but may be performed a plurality of times at predetermined time intervals as necessary. As described above, after the granulated product 6 is naturally dried while preventing the granulated products 6 from adhering to each other by applying vibration, impact, etc., the process proceeds to the curing step. The granulated product 6 may be watered before the start of the curing step.

In the above-mentioned respective embodiments, as the pan-type granulator 1 for granulation, various known pan-type granulators can be used in addition to those described above. For example, if a pan-type granulator 1 in which the bottom wall 2a of the bread 2 is provided with irregularities such as radial patterns, friction between the bottom wall 2a and the kneaded product of the synthetic resin foam, water and a hydraulic binder is obtained. The resistance can be further improved and the stirring efficiency can be improved. Further, the bread-type granulator 1 of the above-mentioned embodiment is one in which the granulated granules 6 overflow from the pan 2 in sequence and continuously granulate, but not limited to this, for example, A closed pan having an upper bottom wall and a lower bottom wall facing each other and an annular side wall connecting peripheral portions of these two bottom walls is provided, and an opening / closing lid provided at an appropriate position such as the side wall is provided. It is also possible to use a pan-type granulator that discharges the granulated product and supplies the kneaded product.

In the above-mentioned embodiment, the case where the lightweight aggregate of the present invention is used as the lightweight concrete aggregate has been described, but the use of the lightweight aggregate of the present invention is not limited to this, and for example, , Mixed with crushed stone for roads such as asphalt paved roads and crushed stone for soft ground improvement, or used in place of the crushed stone, mixed with soil for cultivating plants, or used in place of the soil, heat insulation It can be used for various purposes, such as being used as a lightweight aggregate mixed in a molded plate such as a plate, a sound absorbing plate, a sound insulating plate, and a fireproof plate.

[0068]

As described above, according to the method for producing a lightweight aggregate of the present invention, a synthetic resin foam, water and a hydraulic binder are granulated using a pan type granulator, Since a lightweight aggregate having a required size is generated, for example, as compared with a manufacturing method of cutting or shaping after extruding the kneaded product, the number of manufacturing steps of the lightweight aggregate is reduced and the productivity is improved. be able to. Further, as the manufacturing apparatus, basically only the pan type granulator may be used, so that the manufacturing apparatus can be simplified. Furthermore, since the granulation is performed by rotating the synthetic resin foam, water and a hydraulic binder in the pan of the pan type granulator, the granulated lightweight aggregate is the same as the conventional one. Compared to those cut into small pieces of a predetermined size after extrusion, the shape becomes more spherical, and therefore, for example, when the lightweight aggregate is mixed into concrete as lightweight concrete aggregate, the flowability of concrete is good. There are advantages to be.

If the synthetic resin foam, water and a hydraulic binder are kneaded and then supplied to a pan-type granulator and granulated using the pan-type granulator, a pan-type granulator Compared with the case where a synthetic resin foam, water and a hydraulic binder are individually supplied to, and the size and shape of the lightweight aggregate are more easily aligned than in the case of granulating subsequent to kneading, the lightweight aggregate obtained by granulation There is an advantage that the quality of can be further improved. Further, since the time required for granulation by the pan type granulator is shortened, the productivity is improved.

In the method for producing the lightweight aggregate, if the mixing ratio (W / C) of the hydraulic binder (C) and water (W) is 10 to 30% by weight, a suitable size is obtained. Granulation comes to be performed. That is, when the mixing ratio is less than 10%, the hydration reaction of the hydraulic binder tends to be insufficient, and the binding property of the hydraulic binder tends to be low, and granulation tends to be difficult. is there. On the other hand, the mixing ratio is 30
If it exceeds%, the granular aggregates granulated to a predetermined size are joined together to form huge grains, and the particle size tends to increase to an extent unsuitable as an aggregate.

In the method for producing the lightweight aggregate, if the kneaded product is hydrolyzed at the time of granulating with a pan-type granulator, the unreacted portion of the hydraulic binder is caused by the water during the granulation. A hydration reaction occurs, and the binding property of the hydraulic binder is enhanced, whereby granulation is promoted and there is an advantage that a lightweight aggregate having a required size can be obtained.

In the method for producing the lightweight aggregate, if the mixing ratio of the hydraulic binder and water is 18 to 25% by weight, the granulation can be smoothly performed without adding water during the granulation. This is preferable because it is possible to avoid the problem that the lightweight aggregate easily adheres to the surface of the bread due to water addition during granulation, and to perform granulation continuously for a long time.

In the method of manufacturing the lightweight aggregate, if the lightweight aggregate is coated with the hydraulic binder after granulation, the lightweight aggregate is coated with the hydraulic binder that covers the outer surface of the lightweight aggregate. The strength is increased, and the coated hydraulic binder suppresses the joining of the lightweight aggregates to each other, which makes it difficult to generate huge particles.

In the above-mentioned method for producing a lightweight aggregate, it is preferable to blow hot air to the lightweight aggregate after the granulation to dry it, because it is easy to prevent the lightweight aggregates from adhering to each other.

In the above-mentioned method for manufacturing the lightweight aggregate, if the lightweight aggregates are moved to each other after 2 to 24 hours have elapsed after granulation to prevent the adhesion of the lightweight aggregates, for example, as described above, In addition, as compared with the case where the lightweight aggregate is coated with the hydraulic binder, it is easier to control the specific gravity of the lightweight aggregate and the productivity is improved.

In the above-mentioned method for producing a lightweight aggregate, if the lightweight aggregate is prevented from adhering to each other by sieving the lightweight aggregate 2 to 24 hours after granulation, the surface of the lightweight aggregate can be prevented. Compared with the case of coating with a hydraulic binder,
Management of specific gravity becomes easy and productivity is improved.

In the method for producing the lightweight aggregate, if the lightweight aggregate is hydrolyzed after the granulation and hardening, the hydration reaction of the unreacted hydraulic binder can be caused by the water after the drying. As a result, it is possible to recover and improve the strength of the lightweight aggregate once reduced in the previous drying step.

In the method for producing the lightweight aggregate, when the rotation speed of the pan-type granulator during granulation is 1 to 100 rpm, that is, 1 to 100 revolutions per minute, the pan-type granulator produces It becomes easy to granulate to a suitable size. That is, if the rotation speed of the pan-type granulator is less than 1 rpm, it takes a long time to granulate, and large particles tend to be easily produced. On the other hand, the rotation speed of the bread granulator is 1
If it exceeds 00 rpm, the synthetic resin foam kneaded with water and the hydraulic binder tends to separate from the hydraulic binder. Therefore, the rotation speed of the bread granulator is preferably 1 to 100 rpm.

In the method for manufacturing the lightweight aggregate, when the inclination angle of the pan-type granulator is in the range of 30 to 60 °, there is an advantage that the granulation by the pan-type granulator is smoothly performed. That is, when a kneaded product composed of a synthetic resin foam, water and a hydraulic binder is inserted into an inclined pan of a bread type granulator and rotated, the kneaded product mainly has an inclined bottom wall of the pan. Due to the frictional resistance between and, the mixture is agitated and flowed in the region in the vicinity of the lower end of the bread to be granulated, but if the inclination angle of the bread granulator is less than 30 °,
Since the frictional resistance between the bottom wall of the bread and the kneaded product becomes small, and the stirring efficiency of the kneaded product decreases, smooth granulation tends to be difficult. On the other hand, the tilt angle of the bread granulator is 6
When it exceeds 0 °, the kneaded product stirred in the pan is dispersed and stirred not only in the vicinity of the lower end of the inclined pan but also in almost the entire region of the bottom wall of the pan, so that the stirring region Is too wide, and smooth granulation tends to be difficult. Therefore, the inclination angle of the pan granulator is preferably in the range of 30 to 60 °, and particularly preferably about 45 °.

In the above method for producing a lightweight aggregate, if the lightweight aggregate is used as the lightweight concrete aggregate, the weight of the concrete can be reduced, and the lightweight concrete aggregate can be easily produced by the pan granulator. can do.

[Brief description of drawings]

FIG. 1 is a schematic side view showing a granulating apparatus including a pan-type granulator, a conveyor belt and the like used in a method for manufacturing a lightweight concrete aggregate according to an embodiment of the present invention.

FIG. 2 is a schematic perspective view showing a state in which granulation is performed by the bread granulator.

FIG. 3 is an enlarged sectional view showing the manufactured lightweight concrete aggregate.

FIG. 4 is a cross-sectional view of a concrete product using the lightweight concrete aggregate.

FIG. 5 is a schematic side view showing a granulating device according to another embodiment of the present invention.

[Explanation of symbols]

 1 Bread Type Granulator 2 Bread 6 Granules (lightweight aggregate)

Claims (13)

[Claims] 1. A lightweight aggregate characterized in that a synthetic resin foam, water and a hydraulic binder are granulated using a pan-type granulator to produce a lightweight aggregate of a required size. Production method. 2. A lightweight aggregate having a required size, which is prepared by kneading a synthetic resin foam , water and a hydraulic binder and then supplying the mixture to a pan-type granulator and granulating with the pan-type granulator. A method for producing a lightweight aggregate, which comprises: 3. The method for producing a lightweight aggregate according to claim 1, wherein the mixing ratio of the hydraulic binder and water is 10 to 30% by weight. 4. The method for producing a lightweight aggregate according to claim 3, wherein water is added at the time of granulation by the bread type granulator to obtain a lightweight aggregate having a predetermined size. 5. The method for producing a lightweight aggregate according to claim 1, wherein the mixing ratio of the hydraulic binder and water is 18 to 25% by weight. 6. The production of a lightweight aggregate according to claim 1, wherein the lightweight aggregate is coated with a hydraulic binder after granulation to prevent the lightweight aggregates from adhering to each other. Method. 7. The method for producing a lightweight aggregate according to claim 1, wherein the lightweight aggregate is prevented from adhering to each other by blowing hot air onto the lightweight aggregate after granulation to dry it. . 8. The method according to claim 1, wherein the lightweight aggregates are prevented from adhering to each other by moving the lightweight aggregates to each other about 2 to 24 hours after granulation. Manufacturing method of lightweight aggregate. 9. The lightweight according to any one of claims 1 to 5, wherein the lightweight aggregates are prevented from adhering to each other by sieving the lightweight aggregates after granulation for about 2 to 24 hours. Aggregate manufacturing method. 10. The method for producing a lightweight aggregate according to claim 1, further comprising adding water to the lightweight aggregate after granulation and hardening to increase the strength. 11. The rotation speed of the pan-type granulator during granulation is 1
11. The method for producing a lightweight aggregate according to claim 1, wherein the speed is set to 100 rpm. 12. The tilt angle of the pan-type granulator during granulation is 3
The angle is 0 to 60 °, and the angle is set to 0 to 60 °.
5. A method for producing a lightweight aggregate according to any one of 1. 13. The method for producing a lightweight aggregate according to claim 1, wherein the lightweight aggregate is a lightweight concrete aggregate.