JP2004345896A - Rounded aggregate recycled from concrete waste, method for utilizing the same, and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing rounded aggregate recycled from concrete wastes and being capable of improving strength without increasing a cement amount by removing mud from fine particles just before a fine particle adhesion step. <P>SOLUTION: The method comprises raw material grinding step A of grinding raw aggregate made from concrete wastes so as to round the raw aggregate and fine particle layer adhesion step B of mixing the ground aggregate and the fine particles obtained from step A with cement and water to adhere fine particle layer composed of the fine particles bonded with the cement to the external periphery of the ground aggregate to thereby obtain a rounded aggregate with a rounded contour. The fine particles before being subjected to step B has been freed from mud. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【００６３】
表１で示すように、泥分を除去していない試料１及び試料２に比べて、泥分を除去した試料３及び試料４は、その強度が概ね３０％〜５０％も向上したことが判る。
特に、試料２（Ｗ／Ｃ＝４０％）は、水を少なくしたにもかかわらず、その強度は、試料１（Ｗ／Ｃ＝５０％）とあまり変りがなく、これは、泥分を除去しない場合には、ここまでが強度の限界であると考えられる。
これに比べて試料３及び試料４は、大幅に強度を向上することができた。
又、試料５は、試料４に比べてセメント量を増加した分、著しく強度が向上した。
【００６４】
次に、上記のようにして製造した丸形磨き骨材を用いて製造した高流動コンクリートの配合設計表を以下の表２に示し、その場合の強度試験結果を以下の表３に示す。
この表２及び表３において、試料６は、微細粒層付着工程にかける前の微細粒分から泥分を除去せず、微細粒層付着工程でセメント１０重量％を添加した場合の丸形磨き骨材を使用した例。
試料７は、微細粒層付着工程にかける前の微細粒分から泥分を除去し、微細粒層付着工程でセメント１０重量％を添加した場合の丸形磨き骨材を使用した例。
【００６５】
【表２】

【００６６】
【表３】

【００６７】
表３で示すように、泥分を除去していない試料６に比べて、泥分を除去した試料７は、その強度が概ね５０％も向上したことが判る。
従って、泥分を除去していない試料６は、高強度コンクリートとしての使用が不可能であるのに対し、泥分を除去した試料７は、高強度コンクリートとして十分に使用できる。
【００６８】
【発明の効果】
以上説明してきたように、本発明の丸形骨材（請求項１、３、４）及びその製造方法で（請求項７）得られた丸形骨材は、摩砕骨材の外周面に、泥分を除去した微細粒分をセメントにより結合させた微細粒層を付着させたものである。
このように、比表面積が大きい泥分を微細粒分から除去しているため、泥分が持つコスト面及び強度面の不利を解消して、セメント量を増加することなく、強度を向上させることができる。
【００６９】
又、本発明の丸形骨材（請求項２）及びその製造方法で（請求項９）得られた丸形磨き骨材は、表面に形成された磨き面によって吸水性が抑えられるため、コンクリート用骨材として用いた場合に、転がり易くなり、コンクリートの流動性、いわゆるワーカビリティーを向上させると共に、実積率が向上することによって大幅に単位水量が低減し、コンクリートの品質を向上させることができる。
【００７０】
又、本発明の丸形骨材の製造方法（請求項８）にあっては、湿式により泥分を水洗除去しているため、その除去作業を原料摩砕工程の過程で行なうことができ、その除去作業を能率的かつ効果的に行なうことができる。
また、湿式であるため、得られた摩砕骨材及び微細粒分が含水して、吸水が完了しているため、後の微細粒層付着工程での水量調整が容易になる。
【００７１】
又、本発明の丸形骨材の製造方法（請求項９）にあっては、原料摩砕工程と、微細粒層付着工程と、擦り工程によって、丸形磨き骨材を効率的に製造することができるし、同時に擦れ落ち微細粒分を得ることができるという効果が得られる。
【００７２】
又、本発明の丸形磨き骨材の製造方法（請求項１０）にあっては、微細粒層付着工程で得た丸形骨材を堆積保管しておく場合に、微粒子がいわゆる打ち粉と同様に機能することから、丸形骨材同士の結着を防止させることができる。
【００７３】
また、微細粒層付着工程において、微細粒層を摩砕骨材に振動を加えながら付着させるようにすると（請求項１１）、微細粒層自身が締め固められることによる強度向上、および微細粒層の摩砕骨材に対する付着力の向上が得られる。
【００７４】
また、微細粒層付着工程において、強度増強剤（シリカフューム等）を添加すると（請求項１２）、水と共に強度増強剤が微細粒層や摩砕骨材中に侵入することから、微細粒層や摩砕骨材が高密度になり、強度向上を図ることができる。
【００７５】
又、本発明の丸形骨材の利用方法（請求項５、６）にあっては、建築物や土木構造物の解体に伴い発生するコンクリート廃材について、これをコンクリート用骨材や道路路用骨材として再利用することができる。
【図面の簡単な説明】
【図１】本発明の丸形骨材の製造方法の実施の１形態を示す工程図である。
【図２】原料骨材の断面図である。
【図３】原料骨材の断面図である。
【図４】原料骨材の断面図である。
【符号の説明】
Ａ 原料摩砕工程
Ｂ 微細粒層付着工程
Ｃ 微粒子添加工程
Ｄ 擦り工程
１０ 原料骨材
１０ａ モルタル
１０ｂ 粗骨材
１１ 微細粒分
１２ 摩砕骨材
１３ 微細粒分
１３ａ 泥分
１４ 微細粒層
１５ 丸形骨材
１６ 磨き面
１７ 丸形磨き骨材
１８ 擦れ落ち微細粒分
２ 摩砕装置
２０ ロータリドラム
２１ ロータ
２２ 対向問隙
３ セメント
４ 回転ドラム
４０ 支持フレーム
４１ バネ
４２ 加振装置
４３ ゴムライナ
５ 擦り装置
６ 微粒子
５０ ロータリドラム
５１ ロータ
５２ 対向間隙
７ 水
８ 強度増強剤[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention provides a method for producing a round aggregate in which waste concrete aggregate obtained by crushing concrete waste material is used as a raw material aggregate, and which can be used as an aggregate for concrete or an aggregate for roadbeds, and a method of using the aggregate and a method for using the same. It relates to a manufacturing method.
[0002]
[Prior art]
2. Description of the Related Art In recent years, it has been encouraged to reuse concrete waste generated as a result of demolition of buildings and civil engineering structures as concrete aggregate and road aggregate.
Concrete aggregates made of waste concrete are produced by crushing concrete waste.However, aggregates for concrete that have been crushed have severe irregularities and squareness on the surface. It is difficult to say that it is preferable in terms of the actual product rate and the unit water volume.
Further, conventionally, when reusing concrete waste as aggregate for concrete, the cement content in the concrete waste is removed to collect only the aggregate.
[0003]
Conventionally, as aggregate for concrete, there are fine aggregate having a particle diameter of 5 mm and under, and coarse aggregate having a particle diameter of 5 to 20 mm and 20 to 40 mm. It is said that the quality is high, and for this reason, river sand and sea sand with a round outer shape, river gravel and sea gravel are suitable as aggregate for concrete, and as for crushed stone aggregate, unevenness and squareness of the surface are It is said that it is not preferable to use it as it is because it is intense.
[0004]
As described above, the conventional aggregate for concrete made of waste concrete material has a problem in that it is not preferable in terms of an actual product rate and a unit water amount because the surface of the aggregate for concrete is severely uneven and squared.
In other words, when a concrete aggregate having a rounded outer shape is used, the actual volume ratio is improved, the unit water amount is reduced, and the fluidity of concrete, so-called workability, can be improved.
[0005]
Conventionally, as an aggregate for concrete in which the aggregate is processed so as to have a rounded outer shape, for example, the aggregate is put into a rotating drum, and the aggregate is stirred by the rotating drum. BACKGROUND ART There is known a crushed aggregate in which horns are formed by rubbing or collision between materials.
[0006]
Such an aggregate for concrete is simply obtained by charging the aggregate into a rotating drum and squaring the aggregate only by rubbing or collision between the aggregates. However, the fact is that the outer shape is not yet sufficiently rounded.
[0007]
In order to cope with the above problems, there has been conventionally known a method for producing a round aggregate in which the outer shape is rounded while using concrete waste as a raw material aggregate (see Patent Document 1).
[0008]
[Patent Document 1]
JP-A-2002-193646 (hereinafter referred to as prior art)
[0009]
The production method according to the prior art includes a raw material grinding step in which the raw material aggregate is ground to obtain ground aggregate and fine particles so that the raw material aggregate is squared by waste concrete. ,
By mixing and stirring the cement and water into the milled aggregate and fine particles obtained through this raw material milling step, the fine particles were bonded to the outer peripheral surface of the milled aggregate by cement. The method was provided with a fine-grain layer attaching step of attaching a fine-grain layer to obtain a round aggregate formed into a rounded outer shape.
In this case, in the fine particles obtained in the raw material grinding step, mud (sieve size 0.038 mm or less) is about several% of the total amount of the milled aggregate and the fine particles (normally). , Around 3%).
[0010]
[Problems to be solved by the invention]
Since such a mud has a large specific surface area, the amount of cement used for solidifying the mud becomes excessively large, and the amount of added cement increases accordingly, resulting in a disadvantage in cost.
Further, there is a problem that the adhesive force of the cement is killed by the presence of the mud having a large specific surface area, and the strength of the fine grain layer cannot be improved.
Therefore, if the mud having a large specific surface area is removed, the adhesive force of the cement can be increased and the strength of the fine grain layer can be improved without increasing the cement amount.
[0011]
In the present invention, from such a viewpoint, by removing the mud from the fine particles immediately before performing the fine particle layer attaching step, the concrete can be improved in strength without increasing the amount of cement. It is an object of the present invention to provide a round aggregate using waste material, a method of using the same, and a method of manufacturing the same.
[0012]
[Means for Solving the Problems]
In order to solve the above problems, the round aggregate of the present invention (claim 1)
An outer shape with a rounded shape obtained by attaching a fine-grained layer in which fine particles from which mud has been removed are bonded with cement to the outer peripheral surface of ground material that has been ground by grinding raw material aggregate made of waste concrete The structure was formed as follows.
[0013]
Further, the round aggregate of the present invention (claim 2) has an aspect in which the surface is formed as a polished surface in the round aggregate of the above-described claim 1.
[0014]
In this round aggregate, a particle size of 20 mm under and a particle size of 40 mm under can be used as a raw material aggregate (claims 3 and 4).
[0015]
Next, the method for producing a round aggregate of the present invention (claim 7) is as follows.
A raw material grinding step of grinding the raw material aggregate so as to obtain the corners of the raw material aggregate by the concrete waste material to obtain ground aggregate and fine particles;
The cement and water are mixed with the milled aggregate and the fine particles obtained through this raw material milling step and stirred to mix the fine particles with the cement on the outer peripheral surface of the milled aggregate. A fine grain layer attaching step of attaching a grain layer to obtain a round aggregate formed into a rounded outer shape,
The fine particles before the fine particle layer attaching step were configured such that mud (sieve size 0.038 mm or less) was removed.
[0016]
In the round aggregate manufacturing method (Claim 7), there is an embodiment (Claim 8) in which the raw material grinding step is performed in a wet manner to wash and remove mud.
[0017]
In the production method of the present invention, first, a concrete aggregate is crushed to obtain a raw material aggregate. In this case, steel bars, wood chips and the like contained in the concrete waste material are removed.
In addition, since concrete contains aggregates (coarse aggregates and fine aggregates), raw material aggregates obtained by crushing this waste concrete material include, for example, cement and cement as shown in FIG. The mortar 10a mixed with fine aggregate is attached around the coarse aggregate 10b, or the mortar 10a is mixed with the mortar 10a alone or in a plurality as shown in FIG. As shown in FIG. 4, there are various forms such as a mortar 10a in which only cement and fine aggregate are mixed, and the raw material aggregate referred to in the present invention is a material including all of these. Say.
[0018]
Next, in the raw material grinding step, the raw material aggregate is ground to obtain a ground aggregate having a squared shape of the raw material aggregate, and at the same time, the fine aggregate removed from the squared portion and the like by the grinding. Get the grain size.
Also, the raw material aggregate originally contains fine particles, and the raw material aggregate containing the fine particles is ground in the raw material grinding step. Therefore, at the time of passing through the raw material grinding step, a fine particle having a total amount of the fine particles originally contained and the fine particles generated by the grinding can be obtained.
[0019]
Further, as a grinding device, for example, a rotor is eccentrically provided in a horizontal rotary drum, and the raw material aggregate is agitated while rotating the rotary drum and the rotor in the reverse direction. A grinding device designed to remove tension can be used. Alternatively, the raw material aggregate may be squared using an impeller, Bermac, Hard Bact, Clean Beetle (made by Maruei Shoji Co., Ltd.) or the like.
It should be noted that a ball mill or a rod mill is a crushing apparatus mainly used for crushing a rough stone to obtain a raw material aggregate referred to in the present invention. Very few, not suitable for grinding.
That is, the grinding process refers to a process of removing the corners of the raw material aggregate and rounding it, but it is natural that a part of the raw material aggregate is cracked (crushed) at the time of processing. In particular, Haldbact is designed to be squared while being crushed, and includes processing including such crushing.
The supply of the raw material aggregate, the removal of the milled aggregate and the fine particles after the grinding may be performed by a continuous processing method in which the raw material aggregate is continuously taken out while being continuously supplied, or may be processed by a fixed amount in a batch method. .
[0020]
The milled aggregate and fine particles obtained in the above raw material milling step are subjected to the next fine particle layer attaching step. In this case, the fine particle fraction applied to the fine particle layer attaching step is prepared in advance. This removes mud (sieve size 0.038 mm or less).
As a means for removing the mud, the raw material grinding step may be performed in a wet manner to wash and remove the mud (claim 9).
Further, the fine particles obtained in the raw material grinding step may be classified to remove mud.
In short, it is sufficient that the fine particles to be subjected to the fine particle layer attaching step have the mud removed in advance.
Regarding the removal ratio of the mud, it is preferable to remove as much as possible because it is technically difficult to completely remove all the mud (100%), but at least half of the contained mud is preferable. (50%) or more is desirably removed, and the removal of mud in the present invention means that at least about 50% or more is removed.
[0021]
In addition, when the raw material grinding step is performed in a wet manner to wash and remove mud, the obtained ground aggregate and fine particles are in a water-containing state.
As described above, if the milled aggregate and the fine particles are moistened before being subjected to the fine particle layer attaching step (a draining of about one day is necessary), the milled aggregate and the fine particles Has been completed, it is easy to adjust the amount of water in the subsequent fine particle layer attaching step.
[0022]
In addition, when the raw material grinding step is performed by a wet method, the mud attached to the recesses of the raw material aggregate can be removed by washing with water.
If mud remains in the dents of the milled aggregate, the fine particle layer adhered in the next fine particle layer attaching step is easily peeled off, which causes a reduction in strength.
Therefore, when the raw material grinding step is performed by a wet method, water is washed at the same time as the grinding processing, so that an effect that mud attached to the dent can be effectively removed can be obtained.
[0023]
Next, in the fine particle layer attaching step, the cement and water are mixed with the milled aggregate and the fine particles obtained in the raw material milling step, and the mixture is stirred. Then, a fine particle layer in which the fine particles are bonded by cement is adhered to obtain a round aggregate having a rounded outer shape.
As described above, when the cement and water are mixed and agitated in the milled aggregate and the fine particles, the fine particles are bonded by the adhesive force of the cement, and the fine particle layer to which the fine particles are bonded is rubbed. A round aggregate can be obtained by attaching to the outer peripheral surface of the crushed aggregate.
In this case, since the fine particles are combined with the cement and taken into the fine particle layer, at the time of passing through the fine particle layer attaching step, the fine particles hardly disappear. Regenerated as completely round aggregate.
Then, since the bonding of the fine particles by the cement is performed while stirring, the cement and the fine particles enter into the dents of the milled aggregate, and the dents are filled with the fine particle layer, so that the outer shape as a whole is obtained. Roundness will occur.
[0024]
Conventionally, as a technology for recycling concrete waste, there is a technology for collecting aggregate from concrete waste (for example, Mitsubishi Materials Corporation, Diagate), but this is a technology for collecting only aggregate from concrete waste. It is.
Therefore, components other than the recycled aggregate, that is, mortar components that are not recovered are generated, and it is necessary to treat this as waste. In other words, this conventional recycling technique is a technique for partially reclaiming concrete waste material. As in the present invention, by incorporating fine particles into a fine particle layer, the concrete waste material is almost completely recycled as round aggregate. Technology.
[0025]
As the cement to be mixed, various cements specified in JIS, such as Portland cement type and mixed cement type, and special cements other than JIS standards can be used.
In addition, the mixing ratio of cement is set according to conditions such as the particle size and ratio of the milled aggregate and fine particles.If the amount of cement is too small, the bonding strength cannot be obtained. If the amount is too large, the milled aggregates will solidify and the cost will increase. Therefore, the setting is made while taking into account the maintenance of the adhesive force and excessive hardening.
The mixing ratio of cement is preferably about 10% by weight to about 15% by weight. In order to produce a high-strength round aggregate, the amount of cement to be added may be increased, and a round shape which does not require high strength may be used. In order to produce aggregate, the amount of cement added should be reduced
[0026]
In the fine particle layer attaching step, as described above, the fine particles introduced together with the milled aggregate have a mud content (a sieve size of 0.038 mm or less) removed in advance.
Therefore, without increasing the amount of cement, the adhesive force of the cement can be increased and the strength of the fine grain layer can be improved.
[0027]
Next, the amount of water to be mixed in the fine particle layer attaching step is set so that the fine particles can be combined by the cement, and the milled aggregate is dried in accordance with the dry state of the milled aggregate. It is adjusted so that fine particles can be properly bonded by cement by adding or adding water. Generally, it is preferable to inject about 3 to 7% by weight of water of the raw material aggregate.
In this case, as described above, the raw material grinding step is performed by a wet method, and the milled aggregate and the fine particles are hydrated before being subjected to the fine-grain layer attaching step. Since the water absorption of the particles has been completed, the water amount can be easily adjusted in the subsequent fine particle layer attaching step.
[0028]
In addition, regarding the mixing and stirring in the fine particle layer attaching step, it is desirable that the milled aggregate, the fine particles, the cement, and the water are sufficiently mixed.
For example, using a horizontal rotating drum, milled aggregate, fine particles, and cement are charged from one input port, and the processed round aggregate is taken out from the other while mixing and stirring these with a rotary drum. If it is taken out from the mouth, sufficient mixing and agitation is promoted by the rotating drum, so that the quality becomes uniform and a round aggregate can be obtained continuously.
The apparatus used in the fine particle layer attaching step is not limited to the above-mentioned rotary drum, and for example, a mixing / stirring apparatus or the like provided with rotating blades in a vertical or horizontal container can be used.
[0029]
Next, in the round aggregate manufacturing method of the present invention, after the fine grain layer attaching step, the round aggregates obtained by the fine grain layer attaching step are rubbed together to form a polished surface. There is an aspect in which a rubbing step is provided to obtain a rounded polished aggregate and fine particles rubbed off (claim 9).
[0030]
In this rubbing step, the round aggregates obtained in the fine grain layer attaching step are rubbed with each other to obtain a round polished aggregate whose surface is formed on a polished surface and fine particles rubbing off.
The round aggregate obtained by the fine grain layer attaching step is such that the fine grain layer is attached to the outer peripheral surface of the milled aggregate, so that the surface is rough, the surface area is large, and the water absorption rate is high. .
Therefore, if the surface is formed into a polished surface by this rubbing step, the rough surface roughness can be removed and the surface area can be reduced, thereby suppressing the water absorption. At the same time, fine particles are scraped off from the surface of the fine particle layer, so that fine particles can be obtained by rubbing.
[0031]
When used as an aggregate for concrete, the round aggregate alone does not have fine particles, so there is a problem that the particle size distribution of the fine particles is biased. Therefore, the trouble of separately mixing fine particles can be omitted.
[0032]
Further, as the rubbing device, for example, similarly to the rubbing device used in the above-mentioned grinding step, a rotor is eccentrically provided in a horizontal rotary drum, and a circular drum is formed while rotating the rotary drum and the rotor in reverse. A rubbing device that stirs the aggregate and rubs the surface by rubbing or collision between the round aggregates can be used.
It should be noted that the degree of rubbing may be such that the surface is rough, and it is not always necessary to polish it so as to produce gloss.
[0033]
In the rubbing step, there is no particular limitation on the content of fine rubbing particles produced simultaneously with the round polished aggregate. However, in order to use it as an aggregate for concrete, it is desirable to manage the content of fine particles rubbing off so as to apply to Annex 1 of JISA5308.
In addition, the amount of the fine particles rubbing off is adjusted by adjusting the polishing time to the required amount.
[0034]
Therefore, in the case of a round polished aggregate, the outer shape is rounded and the water absorption is suppressed as compared with the round aggregate, so that when used as a concrete aggregate, the quality as the aggregate is maintained while maintaining the quality as the aggregate. Along with improving the moment, the unit water amount can be reduced, and the fluidity of concrete, so-called workability, can be improved.
Also, among the fine particles rubbing off obtained through the rubbing step, it is also possible to remove ultrafine particles having a sieve size of 0.038 mm or less. When used as an aggregate, the unit water volume can be reduced and the durability of concrete can be improved.
As a means for removing the ultrafine particles in this case, the ultrafine particles may be washed and removed from the rubbed fine particles by performing the rubbing step in a wet manner.
[0035]
Further, when producing the round polished aggregate of the present invention, the raw material grinding step, the fine particle layer attaching step, and the rubbing step may be continuously performed on a series of lines, but usually, Then, a mixture of the milled aggregate obtained in the raw material milling process and the fine particles from which mud has been removed is once taken down from a processing device (for example, a horizontal rotary drum) and is then taken out of the next fine particle layer attaching process. It is put into a processing device (for example, a horizontal rotary drum) and processed, and the round aggregate obtained here is temporarily removed from the processing device, and is then processed in the next rubbing process (for example, a horizontal rotary drum). Then, the round polished aggregate obtained here is taken down from the processing device and shipped.
As described above, when the processed product is taken down each time each process is performed, the processed product is temporarily deposited and stored, but in particular, the round aggregate obtained in the fine-grain layer attaching process includes fine-grained aggregates. Because the layer contains moisture, the round aggregates may be bound together by the weight at the time of deposition.
[0036]
Therefore, in the method for producing a round aggregate of the present invention, as the next step of the fine particle layer attaching step, the fine particles are added to the round aggregate obtained in the fine particle layer attaching step and the mixture is stirred, whereby the round shape is obtained. There is an embodiment in which a fine particle addition step is provided to prevent the binding between the shaped aggregates.
[0037]
When the fine particles are added and stirred in this way, the fine particles function in the same manner as the powder used for so-called buckwheat punching and the powdered powder for preventing the adhesion of rice cakes, and can prevent the binding of round aggregates. it can.
As the fine particles used in the fine particle addition step, only fine particles may be added, or fine particles or coarse aggregate containing the fine particles may be added to add the fine particles.
Further, the ultrafine particles removed in the above-mentioned rubbing step can be used as the fine particles used in this fine particle addition step.
This fine particle addition step is preferably performed subsequent to the fine particle layer adhesion step. Then, the fine particle adding step can be performed continuously to the fine particle layer attaching step.
[0038]
Further, in the method for producing a round aggregate of the present invention, there is a mode (claim 11) in which, in the fine grain layer attaching step, the fine grain layer is attached to the outer peripheral surface of the milled aggregate while applying vibration. .
[0039]
As described above, when the fine grain layer is adhered while applying vibration, the strength is improved by compacting the fine grain layer itself, and the adhesion of the fine grain layer to the milled aggregate is improved.
In addition, as a vibration method, for example, the rotating drum itself or a supporting frame of the rotating drum is elastically supported by a spring, a rubber mat, a rubber bracket, or the like, and a vibration device is attached to the rotating drum. The structure is such that vibration can be applied to the whole or part of the rotating drum.
[0040]
Further, in the method for producing a round aggregate of the present invention, there is an embodiment (claim 12) in which a strength enhancer (for example, silica fume) is added in the fine particle layer attaching step.
[0041]
In this way, when the strength enhancer is added, the strength enhancer penetrates into the fine-grained layer and the milled aggregate together with the water, so that the fine-grained layer and the milled aggregate become dense and improve the strength. Can be planned.
In addition, as a method of adding the strength enhancer, the strength enhancer may be added in advance to the water added in the fine particle layer attaching step, or water and the strength enhancer may be separately supplied, The strength enhancer may be incorporated into water during the processing operation in the grain layer attaching step.
As the strength enhancer, for example, silica fume or the like having a particle diameter of 1/50 to 1/100 of the cement particle diameter is used, and the strength enhancer is added in an amount of about 1 to 30% by weight of the cement amount. ing.
[0042]
The round aggregate of the present invention and the round aggregate and the round polished aggregate manufactured as described above are used as they are or classified, and are used as aggregates for concrete (claim 5) or aggregates for road bases. It can be used as (claim 6).
In this case, the round aggregate obtained through the fine grain layer attaching step has a higher surface absorbency than the round polished aggregate because the surface is roughened, and rather the aggregate of permeable concrete. Or as an aggregate for permeable roadbeds.
At the time of passing the fine particle layer attaching step, since the fine particles are hardly taken into the fine particle layer, when the round aggregate is used as the concrete aggregate, the fine particles prepared separately are required. Need to be mixed.
It is optional to mix the round aggregate with existing aggregates (sea sand, river sand, crushed sand, crushed stone) as necessary.
[0043]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the specific configuration of the present invention is not limited to this embodiment.
FIG. 1 is a process chart showing one embodiment of the method for producing a round aggregate of the present invention.
[0044]
This manufacturing method includes a raw material grinding step A, a fine particle layer attaching step B, a fine particle adding step C, and a rubbing step D, and each step will be described below.
[0045]
The raw material aggregate 10 used in this manufacturing method is obtained by crushing waste concrete. In this case, examples of the crusher include a jaw crusher (primary crushing), a cone crusher (secondary crushing), and an impact crusher ( Tertiary crushing) can be used.
[0046]
In the raw material grinding step A, the raw aggregate 10 obtained by crushing the concrete waste material as described above is ground by the grinding device 2 to obtain a corner aggregate of the raw aggregate 10. At the same time as obtaining 12, fine particles 13 cut from a cornered portion or the like by grinding are obtained.
Then, the raw material grinding step A is performed by a wet method, and the mud 13a is washed and removed from the obtained fine particles 13 with water.
[0047]
As the raw material aggregate 10, waste concrete aggregate having a particle size of 20 mm or less or waste concrete aggregate having a particle size of 40 mm or less can be used.
[0048]
As an apparatus for performing a grinding process, a rotor 21 having a projection (not shown) formed on an outer peripheral surface is eccentrically provided inside a horizontal rotary drum 20 having a ridge (not shown) formed on an inner peripheral surface. A predetermined amount of raw material aggregate 10 is charged into a rotary drum 20 using a grinding device 2 (for example, Hurricane manufactured by Shinroku Seiki Co., Ltd.), and the rotary drum (shell) 20 and the rotor 21 are inverted. While rotating, the raw material aggregate 10 is sandwiched between the opposed gaps 22 and agitated so that the raw material aggregates 10 and 10 are rubbed against each other, so that the raw material aggregates 10 are rounded to make them square.
In this case, the diameter of the rotary drum 20 is about 1.6M, the rotation speed thereof is 10 to 20 rpm, and the rotation speed of the rotor 21 is 150 to 230 rpm.
In addition, at the time of passing through the raw material grinding step A, the amount of the finely ground particles 13 combined with the finely divided raw materials 11 originally contained in the raw material aggregate 10 is obtained.
[0049]
Next, in the fine particle layer attaching step B, the cement 3 and the water 7 are mixed and stirred into the milled aggregate 12 and the fine particles 13 obtained in the raw material milling step A. In this case, the mud 13a contained in the fine particles 13 has been washed and removed in advance.
In the fine particle layer attaching step B, the fine particle layer 14 in which the fine particles 13 are bonded by the cement 3 is adhered to the outer peripheral surface of the milled aggregate 12 to form a round shape having a round shape. An aggregate 15 is obtained.
In this case, since the bonding of the fine particles 13 by the cement 3 is performed while stirring, the fine particles 13 bonded by the cement 3 enter the dents of the milled aggregate 12, and the dents are filled with the fine particle layer 14. As a result, the outer shape becomes round as a whole.
[0050]
In addition, since the fine particle fraction 13 is taken into the fine particle layer 14, the fine particle fraction 13 is almost eliminated at the time of passing the fine particle layer attaching step B.
[0051]
As the cement 3 to be mixed, ordinary Portland cement is used. The mixing ratio of the cement 3 is about 10% by weight of the raw material aggregate 10.
[0052]
In order to obtain the adhesive strength by the cement 3, it is natural that water is necessary. In this embodiment, about 5% by weight of water 7 of the raw material aggregate is injected.
In this case, a strength enhancer (silica fume) 8 is added to the water 7 in advance, and when water to which such a strength enhancer 8 is added is used, the strength enhancer 8 together with the water 7 is used as the fine particle layer 14 or the like. Since it penetrates into the milled aggregate 12, the density of the fine grain layer 14 and the milled aggregate 12 becomes high, and the strength can be improved.
As the strength enhancer 8, for example, silica fume is used, and about 5% by weight of the cement amount is added.
[0053]
For the mixing and stirring in the fine particle layer attaching step B, a horizontal rotary drum 4 is used, and in this rotary drum 4, a crushed aggregate 12 and a fine particle fraction 13 taken out from the crusher 2, Cement 3 and water 7 are introduced from an inlet port opened at one end, and are moved toward an outlet port opened at the other end while being mixed and stirred by a rotary drum 4. Is taken out from the outlet.
The diameter of the rotating drum 4 is about 3M, and the number of rotations is 2 to 20 rpm.
[0054]
Further, in the fine particle layer adhering step B, the fine particles 13 and the cement 3 may adhere to the inner surface of the rotary drum 4 and solidify, thereby causing contamination.
Therefore, in this embodiment, a rubber liner 43 having a diameter slightly smaller than the inner diameter of the rotating drum 4 is fixed to the inner surface of the rotating drum 4 at one or several places, and the rubber liner 43 is minutely vibrated by its elastic vibration. The adhesion of the particles 13 and the cement 3 is prevented.
[0055]
In the fine particle layer attaching step B, the fine particle layer 14 is adhered to the milled aggregate 12 while applying vibration. In this manner, when the vibration is applied, the fine particle layer 14 itself is compacted. As a result, the strength is improved, and the adhesion of the fine grain layer 14 to the milled aggregate 12 is improved.
In this embodiment, the supporting frame 40 of the rotating drum 4 is elastically supported by a spring 41, and a vibration device 42 is attached. The vibration (for example, about 900 rpm, amplitude (0.5-7.0 mm) is applied to the entire rotary drum 4.
[0056]
Next, in the fine particle addition step C, the fine particles 6 are added to the round aggregate 15 obtained in the fine particle layer attaching step B and the mixture is stirred to prevent the round aggregates 15 from binding to each other. It is.
When the round aggregate 15 obtained in the fine particle layer attaching step B is deposited and stored, the round aggregate 15 may be bound due to moisture and the weight at the time of deposition.
Therefore, if the fine particles 6 are added to the round aggregate 15 and stirred, the fine particles 6 function in the same manner as so-called powdered powder, and the binding of the round aggregates 15 can be prevented.
In this case, the fine particles 6 are added at a position just before the outlet of the rotary drum 4 and are stirred by the rotation of the rotary drum 4. Thereby, the fine particle adding step C can be performed continuously from the fine particle layer attaching step B.
[0057]
The round aggregate 15 manufactured as described above can be used as it is or classified and used as an aggregate for concrete or an aggregate for road foundation. In the present embodiment, the aggregate is further subjected to a rubbing step D. In this case, a round polished aggregate 17 in which the surface of a round aggregate 15 is formed on a polished surface 16 and fine particles 18 rubbing off are obtained.
[0058]
The round aggregate 15 that has been subjected to the fine grain layer attaching step B has a high surface area and a large surface area, and thus has a high water absorption when used as an aggregate for concrete.
Therefore, when the surface is formed on the polished surface 16 by the rubbing step D, the rough surface can be removed, the surface area can be reduced, and the water absorption can be suppressed as compared with the round aggregate 15. .
Note that the round polished aggregate 17 had a roundness and the roughness of the surface was removed compared to the round aggregate 15, which could be sufficiently confirmed visually and by touch.
[0059]
At the same time, the fine particles 18 are rubbed off from the surface of the fine particle layer 14, so that the fine particles 18 rub off in addition to the fine particles 6 added in the fine particle addition step C can be obtained. In this case, in order to use it suitably as an aggregate for concrete, it is desirable that the combined amount of the fine particles 6 and the rub-off fine particles 18 be controlled so as to be applied to Annex 1 of JISA 5308.
[0060]
As a device for performing the rubbing process, for example, a rubbing device in which a rotor 51 is eccentrically provided in a horizontal rotary drum (shell) 50, like the grinding device 2 used in the raw material grinding process A described above. 5 (for example, Hurricane manufactured by Shinroku Seiki Co., Ltd.), the round aggregate 15 taken out of the rotary drum 4 in the fine grain layer attaching step B is put into a rotary drum 50, and the rotary drum 50 While rotating the rotor 51 in the reverse direction, the round aggregates 15 are sandwiched in the facing gaps 52, and the round aggregates 15 and 15 are agitated so as to rub each other to remove the roughness of the surface.
The rotary drum 50 has a diameter of about 1.6M, its rotation speed is 10 to 20 rpm, and the rotation speed of the rotor 51 is 150 to 230 rpm.
In this case, in the grinding step A, the amount of eccentricity of the rotor 21 is increased and the facing gap 22 is set to be narrow in order to strengthen the friction between the raw material aggregates 10, 10, while in the grinding step D, In order to reduce the friction between the round aggregates 15, 15, the amount of eccentricity of the rotor 51 is reduced and the facing gap 52 is set wide.
[0061]
Next, Table 1 below shows the strength test results of the concrete manufactured using the round polished aggregate manufactured as described above.
In Table 1, Sample 1 and Sample 2 are round polished bones in the case where 10% by weight of cement was added in the fine grain layer attaching step without removing mud from the fine grains before the fine grain layer attaching step. Example using wood.
Samples 3 and 4 are examples using a round polished aggregate obtained by removing mud from the fine particles before the fine particle layer attaching step and adding 10% by weight of cement in the fine particle layer attaching step.
Sample 5 is an example of using a round polished aggregate in which 15% by weight of cement was added in the fine-grain layer adhering step by removing mud from the fine granules before the fine-grain layer adhering step.
[0062]
[Table 1]

[0063]
As shown in Table 1, it can be seen that the strength of the samples 3 and 4 from which the mud was removed was improved by about 30% to 50% compared to the samples 1 and 2 from which the mud was not removed. .
In particular, the strength of sample 2 (W / C = 40%) was not much different from that of sample 1 (W / C = 50%) despite the reduced amount of water. If not, this is considered to be the strength limit.
In comparison, the strengths of Samples 3 and 4 were significantly improved.
In addition, the strength of Sample 5 was remarkably improved as compared with Sample 4 because the amount of cement was increased.
[0064]
Next, Table 2 below shows a composition design table of the high-fluidity concrete manufactured using the round polished aggregate manufactured as described above, and Table 3 below shows the strength test results in that case.
In Tables 2 and 3, Sample 6 shows a round polished bone in which 10% by weight of cement was added in the fine-grain layer attaching step without removing mud from the fine-grain fraction before the fine-grain layer attaching step. Example using wood.
Sample 7 is an example using a round polished aggregate obtained by removing mud from the fine particles before the fine particle layer attaching step and adding 10% by weight of cement in the fine particle layer attaching step.
[0065]
[Table 2]

[0066]
[Table 3]

[0067]
As shown in Table 3, it can be seen that the strength of the sample 7 from which the mud was removed was improved by about 50% as compared with the sample 6 from which the mud was not removed.
Therefore, Sample 6 from which mud has not been removed cannot be used as high-strength concrete, whereas Sample 7 from which mud has been removed can be sufficiently used as high-strength concrete.
[0068]
【The invention's effect】
As described above, the round aggregate (claims 1, 3, and 4) of the present invention and the round aggregate obtained by the manufacturing method (claim 7) are applied to the outer peripheral surface of the milled aggregate. And a fine particle layer in which fine particles from which mud has been removed are bonded by cement.
As described above, since the mud having a large specific surface area is removed from the fine particles, the disadvantages of the cost and strength of the mud are eliminated, and the strength can be improved without increasing the amount of cement. it can.
[0069]
In addition, the round aggregate (claim 2) of the present invention and the round polished aggregate obtained by the method for producing the same (claim 9) can reduce the water absorption by the polished surface formed on the surface, and therefore, the concrete When used as an aggregate for use, it is easy to roll and improves the fluidity of concrete, so-called workability, and by improving the actual loading ratio, the unit water amount is greatly reduced and the quality of concrete can be improved .
[0070]
In the method for producing a round aggregate of the present invention (claim 8), since the mud is washed and removed by a wet method, the removal can be performed in the course of the raw material grinding step. The removal operation can be performed efficiently and effectively.
In addition, since it is a wet type, the obtained milled aggregate and fine particles are hydrated, and the water absorption is completed, so that the amount of water can be easily adjusted in the subsequent fine particle layer attaching step.
[0071]
In the method for producing a round aggregate of the present invention (claim 9), a round polished aggregate is efficiently produced by a raw material grinding step, a fine grain layer attaching step, and a rubbing step. And at the same time, it is possible to obtain the effect of obtaining fine particles by rubbing.
[0072]
Further, in the method for producing a round polished aggregate of the present invention (claim 10), when the round aggregate obtained in the fine grain layer attaching step is deposited and stored, the fine particles are so-called powdered powder. Since they function similarly, it is possible to prevent the round aggregates from binding to each other.
[0073]
In the fine grain layer attaching step, when the fine grain layer is attached to the milled aggregate while applying vibration (claim 11), the strength is improved by compacting the fine grain layer itself, and the fine grain layer is improved. Of the present invention can be improved.
[0074]
In addition, when a strength enhancer (silica fume or the like) is added in the fine grain layer attaching step (claim 12), the strength enhancer penetrates into the fine grain layer and the milled aggregate together with water. The density of the milled aggregate becomes high, and the strength can be improved.
[0075]
Further, in the method of using the round aggregate of the present invention (claims 5 and 6), concrete waste generated due to dismantling of a building or civil engineering structure is used for concrete aggregate or road. It can be reused as aggregate.
[Brief description of the drawings]
FIG. 1 is a process chart showing one embodiment of a method for producing a round aggregate of the present invention.
FIG. 2 is a sectional view of a raw material aggregate.
FIG. 3 is a sectional view of a raw material aggregate.
FIG. 4 is a sectional view of a raw material aggregate.
[Explanation of symbols]
A Raw material grinding process
B Fine grain layer attachment process
C Fine particle addition process
D Rubbing process
10 Raw material aggregate
10a mortar
10b Coarse aggregate
11 fine particles
12 Milled aggregate
13 Fine grains
13a Mud
14 Fine grain layer
15 Round aggregate
16 Polished surface
17 Round polished aggregate
18 Fine grain size
2 Grinding equipment
20 rotary drum
21 rotor
22 Opponent Interaction
3 cement
4 rotating drum
40 Support frame
41 spring
42 Exciter
43 Rubber Liner
5 Rubbing device
6 fine particles
50 Rotary drum
51 rotor
52 Opposed gap
7 water
8 Strength enhancer

Claims (12)

A rounded outer shape obtained by attaching a fine-grained layer in which fine particles from which mud has been removed are bonded with cement to the outer peripheral surface of the ground aggregate obtained by grinding the raw material aggregate made of concrete waste material to make it square. A round aggregate characterized by being formed in. The round aggregate according to claim 1, wherein the surface is formed as a polished surface. The round aggregate according to claim 1 or 2, wherein the particle diameter of the raw material aggregate is under 20 mm. The round aggregate according to claim 1 or 2, wherein the particle size of the raw material aggregate is under 40 mm. A method of using a round aggregate, wherein the round aggregate according to any one of claims 1 to 4 is used as it is or classified and used as an aggregate for concrete. A method of using a round aggregate, wherein the round aggregate according to any one of claims 1 to 4 is used as it is or classified and used as an aggregate for a roadbed. A raw material grinding step in which the raw material aggregate is ground to obtain a crushed aggregate and fine particles by grinding the raw material aggregate so as to remove the corner of the raw material aggregate, and the raw material aggregate obtained through this raw material grinding step. By mixing and stirring cement and water to the milled aggregate and the fine particles obtained, the fine particle layer in which the fine particles are bonded by cement is attached to the outer peripheral surface of the milled aggregate, and the rounded surface is formed. With a fine-grained layer attaching step to obtain a round aggregate formed in an outer shape having
A method for producing a round aggregate using waste concrete material, wherein the fine particles before the fine particle layer attaching step is obtained by removing mud. The method for producing a round polished aggregate according to claim 7,
A method for producing a round aggregate using a concrete waste material in which the raw material grinding step is performed by a wet method to wash and remove mud with water. The method for producing a round polished aggregate according to claim 7 or 8,
After the fine-grain layer attaching step, the round aggregates obtained by the fine-grain layer attaching step are rubbed with each other to obtain a round polished aggregate whose surface is formed on a polished surface and a rub-off fine particle fraction. A method for producing a round aggregate having a rubbing step. The method for producing a round aggregate according to any one of claims 7 to 9,
Fine particles added to the round aggregate obtained by the fine particle layer attaching step as a next step of the fine particle layer attaching step and stirred to prevent the binding of the round aggregates. A method for producing a round aggregate provided with an addition step. The method for producing a round aggregate according to any one of claims 7 to 10,
A method for producing a round aggregate in which a fine grain layer is attached to an outer peripheral surface of a ground aggregate while applying vibration in a fine grain layer attaching step. The method for producing a round aggregate according to any one of claims 7 to 11,
A method for producing a round aggregate, wherein a strength enhancer is added in a fine particle layer attaching step.

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