JP2008127969A - Manufacturing method of roadbed material from waste concrete - Google Patents

Manufacturing method of roadbed material from waste concrete Download PDF

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JP2008127969A
JP2008127969A JP2006317882A JP2006317882A JP2008127969A JP 2008127969 A JP2008127969 A JP 2008127969A JP 2006317882 A JP2006317882 A JP 2006317882A JP 2006317882 A JP2006317882 A JP 2006317882A JP 2008127969 A JP2008127969 A JP 2008127969A
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slag
blast furnace
concrete waste
crushed
concrete
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JP4972243B2 (en
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Katsunori Takahashi
克則 高橋
Koichi Tozawa
宏一 戸澤
Hirochika Moriyasu
弘周 守安
Mitsuharu Kagawa
光治 香川
Takuya Matsumoto
卓也 松本
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JFE Steel Corp
Maeda Road Construction Co Ltd
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Maeda Road Construction Co Ltd
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    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02WCLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
    • Y02W30/00Technologies for solid waste management
    • Y02W30/50Reuse, recycling or recovery technologies
    • Y02W30/91Use of waste materials as fillers for mortars or concrete

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Abstract

<P>PROBLEM TO BE SOLVED: To manufacture a roadbed material and an earthwork material capable of preventing elution of chromium from waste concrete effectively. <P>SOLUTION: In this method for manufacturing the roadbed material and/or the earthwork material by crushing and treating the waste concrete, the slag obtained after being gradually cooled in a blast furnace within one month after it is crushed and treated is mixed with the crushed and treated waste concrete. Since reduction capacity of the slag can be obtained to the maximum extent by mixing the crushed and treated slag with the waste concrete while reduction capacity of a crushed face of the slag is not reduced, hexavalent chromium in the waste concrete is effectively reduced, and the roadbed material and the earthwork material capable of preventing elution of chromium from the waste concrete greatly can be manufactured. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

本発明は、建設廃材などとして発生するコンクリート廃材から路盤材や土工材を製造するための方法に関するものである。   The present invention relates to a method for producing a roadbed material and an earthwork material from concrete waste generated as construction waste.

従来、建設廃材などとして発生するコンクリート廃材を、路盤材や埋め戻し材などの土工材料として利用することが広く行われている。
ところで、セメントには、その製造工程で混入するクロムに由来する6価クロムが微量に含まれることがあるが、セメントが一旦コンクリートとして固化してしまえば、セメントからの6価クロム溶出のおそれは殆どない。ただし、中性化(劣化)が進んだコンクリートを細かく砕いた場合には、土壌環境基準を超える6価クロムの溶出の可能性が指摘されている。また、最近ではクロムなどの重金属による環境負荷をより軽減することが求められており、特に、路盤材や埋め戻し材は土壌との接触や透過水分の地下水への合流が考えられことから、クロムの溶出をより確実に押さえ込むことが好ましいと言える。
2. Description of the Related Art Conventionally, concrete waste generated as construction waste has been widely used as earthwork materials such as roadbed materials and backfill materials.
By the way, the cement may contain a small amount of hexavalent chromium derived from chromium mixed in the manufacturing process, but once the cement is solidified as concrete, there is a risk of elution of hexavalent chromium from the cement. Almost no. However, it has been pointed out that hexavalent chromium that exceeds soil environmental standards may be eluted when concrete that has been neutralized (deteriorated) is finely crushed. Recently, it has been demanded to further reduce the environmental burden caused by heavy metals such as chromium. In particular, roadbed materials and backfill materials are considered to come into contact with soil and permeate to the groundwater. It can be said that it is preferable to more reliably suppress elution of.

このような観点から、特許文献1には、路盤材用に破砕されたコンクリート廃材に高炉徐冷スラグの粉砕物を混合し、路盤材(コンクリート廃材)からの6価クロムの溶出を抑制するようにした方法が提案されている。
この方法は、高炉徐冷スラグがもつ還元能力に着目し、その粉砕物をコンクリート廃材と混合することにより、コンクリート廃材中の6価クロムを3価クロムに還元することを狙いとしている。
特開2005−240313号公報
From such a point of view, Patent Document 1 describes that pulverized blast furnace slow-cooled slag is mixed with concrete waste material crushed for roadbed material to suppress elution of hexavalent chromium from the roadbed material (concrete waste material). A proposed method has been proposed.
This method focuses on the reducing ability of blast furnace chilled slag and aims to reduce hexavalent chromium in the waste concrete to trivalent chromium by mixing the pulverized product with the concrete waste.
JP 2005-240313 A

しかし、本発明者らが検討したところによれば、上記従来技術では、高炉徐冷スラグを混合することによる効果は得られるものの、その効果は必ずしも期待通りの十分なものとは言えず、特に、近年厳しさを増しつつある環境基準に対して、十分に対応できなくなる可能性もある。
したがって本発明の目的は、以上のような従来技術の課題を解決し、コンクリート廃材からのクロム溶出が効果的に抑制される路盤材や土工材を製造することにある。
However, according to the study by the present inventors, in the above-mentioned conventional technology, although the effect by mixing the blast furnace slow cooling slag can be obtained, the effect is not necessarily sufficient as expected. However, there is a possibility that it will not be possible to sufficiently respond to environmental standards that are becoming increasingly severe in recent years.
Accordingly, an object of the present invention is to solve the above-described problems of the prior art and to manufacture roadbed materials and earthwork materials in which chromium elution from concrete waste is effectively suppressed.

本発明者らは、高炉徐冷スラグの還元能力を最大限に発現させる方法を見出すべく検討した結果、以下のような知見を得た。まず、従来技術で使用していた高炉徐冷スラグは表面の還元能力が低下しており、このように還元能力が低下したスラグを再破砕して、その還元能力を評価した結果、内部は十分に還元能力が維持されていることが判った。これにより、(i)従来技術では、粉砕してからしばらく時間が経過した高炉徐冷スラグを、プラントなどでコンクリート廃材と混合しているが、高炉徐冷スラグが粉砕されてからコンクリート廃材に混合されるまでの間に表面(破砕面)が酸化され、還元能力が低下すること、(ii)特に、粉砕によって高炉徐冷スラグの比表面積が大きくなるため、大気などとの接触により還元能力が劣化しやすいこと、(iii)したがって、高炉徐冷スラグの還元能力を最大限に発揮させるには、破砕されて新しい破砕面が生じた高炉徐冷スラグを速やかにコンクリート廃材と混合・接触させることが有効であること、が判った。ここで、従来技術において粉砕してからしばらく時間が経過した高炉徐冷スラグを使用していたのは、一般に土木材料等に使用する高炉徐冷スラグは、硫黄分の溶出を抑えるために大気中で相当期間安定化させてから出荷されるためである。   The present inventors have studied to find out a method for maximizing the reducing ability of the blast furnace slow cooling slag, and as a result, have obtained the following knowledge. First, the blast furnace slow-cooled slag used in the prior art has a reduced surface reducing ability, and as a result of re-crushing the slag with reduced reducing ability and evaluating the reducing ability, the inside is sufficient. It was found that the reducing ability was maintained. As a result, (i) in the prior art, the blast furnace slow-cooled slag, which has been crushed for a while, is mixed with the concrete waste material at the plant, etc., but after the blast furnace slow-cooled slag is ground, it is mixed with the concrete waste material. The surface (crushed surface) is oxidized before the reduction, and the reduction ability is reduced. (Ii) Especially, the reduction surface ability is increased by contact with the atmosphere because the specific surface area of the blast furnace slow cooling slag is increased by grinding. (Iii) Therefore, in order to maximize the reduction capacity of blast furnace chilled slag, the blast furnace chilled slag that has been crushed to produce a new crushed surface must be quickly mixed and contacted with concrete waste. Was found to be effective. Here, the blast furnace slow-cooled slag that has been used for a while since pulverized in the prior art is generally used for blast furnace slow-cooled slag used in civil engineering materials, etc. This is because the product is shipped after being stabilized for a considerable period.

また、上記の観点からは、一連の製造工程において、高炉徐冷スラグを破砕処理した後、コンクリート廃材に混合することが最も好ましいが、その際、高炉徐冷スラグを水を含んだ状態で破砕処理することにより、この水分中にスラグの還元性硫黄が一部溶解し、コンクリート廃材との混合と同時に速やかに6価クロムの還元作用を及ぼすことができるため、初期における6価クロム溶出をより効果的に抑制できることが判った。   From the above viewpoint, in the series of manufacturing steps, it is most preferable to crush the blast furnace slow-cooled slag and then mix it with the concrete waste material. At that time, the blast furnace slow-cooled slag is crushed in a state containing water. By treating, some of the reducing sulfur of the slag dissolves in this moisture, and it can immediately reduce the hexavalent chromium at the same time as mixing with the concrete waste material. It was found that it can be effectively suppressed.

本発明はこのような知見に基づきなされたもので、以下を要旨とするものである。
[1]コンクリート廃材を破砕処理して路盤材及び/又は土工材を製造する方法であって、破砕処理されたコンクリート廃材に、破砕処理されてから1ヶ月以内の高炉徐冷スラグを混合することを特徴とする、コンクリート廃材からの路盤材等の製造方法。
[2]上記[1]の製造方法において、コンクリート廃材100質量部に対して高炉徐冷スラグを2〜10質量部の割合で混合することを特徴とする、コンクリート廃材からの路盤材等の製造方法。
The present invention has been made on the basis of such findings and has the following gist.
[1] A method for producing a roadbed material and / or earthwork material by crushing concrete waste material, and mixing the crushed concrete waste material with blast furnace chilled slag within one month after crushing treatment. A method for producing roadbed materials from concrete waste.
[2] In the production method of [1], the blast furnace chilled slag is mixed at a ratio of 2 to 10 parts by mass with respect to 100 parts by mass of the concrete waste, and the production of roadbed material and the like from the concrete waste Method.

[3]上記[1]又は[2]の製造方法において、コンクリート廃材に、粒径10mm以下の粒子の割合が30mass%以上である高炉徐冷スラグを混合することを特徴とする、コンクリート廃材からの路盤材等の製造方法。
[4]上記[1]〜[3]のいずれかの製造方法において、一連の製造工程において、高炉徐冷スラグを破砕処理した後、コンクリート廃材に混合することを特徴とする、コンクリート廃材からの路盤材等の製造方法。
[5]上記[4]の製造方法において、高炉徐冷スラグを水を含んだ状態で破砕処理することを特徴とする、コンクリート廃材からの路盤材等の製造方法。
[3] In the manufacturing method according to [1] or [2] above, from the concrete waste material, the concrete waste material is mixed with blast furnace slow-cooled slag in which the proportion of particles having a particle size of 10 mm or less is 30 mass% or more. Manufacturing method for roadbed materials.
[4] In the production method according to any one of [1] to [3] above, the blast furnace slow-cooled slag is crushed in a series of production steps, and then mixed with the concrete waste material. Manufacturing method for roadbed materials.
[5] A method for producing a roadbed material or the like from waste concrete material, wherein the blast furnace slow-cooled slag is crushed in a state containing water in the production method of [4].

本発明によれば、破砕処理された高炉徐冷スラグを破砕面の還元能力が低下しないうちにコンクリート廃材に混合することにより、高炉徐冷スラグがその還元能力を最大限に発揮できるので、コンクリート廃材中の6価クロムが効果的に還元され、コンクリート廃材からの6価クロムの溶出が高度に抑制された路盤材や土工材を製造することができる。
また、請求項4に係る発明によれば、コンクリート廃材中の6価クロムがより効果的に還元され、コンクリート廃材からの6価クロムの溶出抑制効果をさらに高めることができる。さらに、請求項5に係る発明によれば、初期におけるコンクリート廃材からの6価クロム溶出をより効果的に抑制できる。
According to the present invention, by mixing the blast furnace chilled slag that has been crushed into the concrete waste before the reduction ability of the crushing surface is reduced, the blast furnace chilled slag can maximize its reduction ability, It is possible to produce roadbed materials and earthwork materials in which hexavalent chromium in the waste material is effectively reduced and elution of hexavalent chromium from the concrete waste material is highly suppressed.
Moreover, according to the invention which concerns on Claim 4, hexavalent chromium in concrete waste materials is reduced more effectively, and the elution inhibitory effect of hexavalent chromium from concrete waste materials can further be heightened. Furthermore, according to the invention which concerns on Claim 5, the hexavalent chromium elution from the concrete waste material in the initial stage can be suppressed more effectively.

本発明では、コンクリート廃材を破砕処理して路盤材及び/又は土工材を製造する方法であって、破砕処理されたコンクリート廃材に、破砕処理されてから1ヶ月以内の高炉徐冷スラグを混合するものである。なお、本発明及び以下の説明において使用するコンクリート廃材及び高炉徐冷スラグの粒径は、当該篩い目を有する篩いを用いて規定される粒径を意味する。篩いの寸法は、JIS Z 8801等に代表されるものが使用できる。
本発明の製造対象は、路盤材及び/又は土工材(以下、便宜上「路盤材等」という場合がある)である。土工材としては、例えば、埋め戻し材、炉床材、路盤材以外の敷設材などが挙げられるが、これらに限定されるものではない。
The present invention is a method for producing a roadbed material and / or earthwork material by crushing concrete waste material, and mixing the crushed concrete waste material with blast furnace chilled slag within one month after crushing treatment. Is. In addition, the particle size of the concrete waste material and blast furnace slow cooling slag used in the present invention and the following description means a particle size defined using a sieve having the sieve mesh. As the size of the sieve, those represented by JIS Z 8801 and the like can be used.
The manufacturing object of the present invention is a roadbed material and / or earthwork material (hereinafter sometimes referred to as “roadbed material or the like” for convenience). Examples of the earthwork material include, but are not limited to, a backfill material, a hearth material, a laying material other than a roadbed material, and the like.

本発明で用いるコンクリート廃材は、建設廃材が最も代表的なものであるが、これに限定されるものではない。また、廃材という性質上、不可避的にコンクリート以外の廃材が混入することを妨げない。通常、コンクリート廃材は粒径40mm以下に破砕処理されて路盤材等として用いられる。
高炉徐冷スラグは、高炉スラグ(溶融スラグ)を徐冷して得られる結晶質主体のスラグであり、生成した状態においては還元性硫黄を含んでいる。高炉徐冷スラグは、高炉水砕スラグが細粒状の形態で生成するのに対して、溶融スラグが塊状に固化して生成するものである。
The concrete waste material used in the present invention is most typically a construction waste material, but is not limited thereto. Moreover, it does not prevent that waste materials other than concrete are mixed inevitably on the property of waste materials. Usually, the concrete waste material is crushed to a particle size of 40 mm or less and used as a roadbed material or the like.
Blast furnace slow-cooled slag is a crystalline-based slag obtained by slowly cooling blast furnace slag (molten slag), and contains reducing sulfur in the produced state. The blast furnace slow-cooled slag is produced by solidifying a blast furnace granulated slag in a fine granular form, whereas a molten slag is solidified into a lump.

このような高炉徐冷スラグをコンクリート廃材と混合すると、スラグ中の還元性硫黄がコンクリート廃材に含まれる6価クロムを3価クロムに還元し、その結果、コンクリート廃材からの6価クロムの溶出を抑制する。しかし、さきに述べたように、従来技術では、粉砕してからしばらく時間が経過した高炉徐冷スラグをコンクリート廃材と混合しているため、混合前に高炉徐冷スラグ表面(破砕面)が酸化され、還元能力が低下していたものである。このように粉砕してから時間が経過した高炉徐冷スラグを使用していたのは、生成したまま或いは粉砕したままの高炉徐冷スラグは透過水による硫黄流出のおそれがあるため、従来の高炉徐冷スラグの出荷形態では、大気中で相当期間(通常6ヶ月以上)安定化させてから出荷していたためである。   When such blast furnace slow-cooled slag is mixed with concrete waste, reducing sulfur in the slag reduces hexavalent chromium contained in the concrete waste to trivalent chromium, and as a result, elution of hexavalent chromium from the concrete waste Suppress. However, as mentioned earlier, in the conventional technology, the blast furnace slow-cooled slag, which has been crushed for a while, is mixed with the concrete waste material, so the surface of the blast furnace slow-cooled slag (crushed surface) is oxidized before mixing. As a result, the reducing ability has been reduced. The reason why the blast furnace slow-cooled slag was used after pulverization in this way is that the blast furnace slow-cooled slag as it is produced or crushed may cause sulfur outflow due to permeate. This is because the slow cooling slag is shipped after being stabilized in the atmosphere for a considerable period (usually 6 months or more).

高炉徐冷スラグは破砕処理された直後から破砕面の酸化が徐々に進むが、一般には破砕処理されて3ヶ月程度すぎると破砕面の酸化による還元能力の劣化が顕在化してくる。したがって、破砕処理されてから1ヶ月以内であれば、破砕面の酸化はさほど進行しないため、相応の還元能力を発揮できる。そこで本発明では、破砕処理されたコンクリート廃材に、破砕処理されてから1ヶ月以内の高炉徐冷スラグを混合する。これにより、破砕後の未だ還元能力が低下していない破砕面(すなわち還元性硫黄が酸化されることなく潤沢に存在する破砕面)を有する高炉徐冷スラグをコンクリート廃材と混合・接触させることができ、高炉徐冷スラグの6価クロムの還元能力を最大限に発現させることができる。
コンクリート廃材は、その材齢が高いほどセメント水和物とクロムの結合力が弱まり、6価クロムが溶出しやすくなる。一方、高炉徐冷スラグは破砕粒度が小さいほど比表面積が大きくなり、6価クロムの還元能力が高くなる。その点、本発明は、高炉徐冷スラグの破砕粒度を自在に調整できるので、コンクリート廃材の材齢(6価クロムの溶出しやすさ)に応じて6価クロムの溶出抑制効果を適切に得ることができる。
The blast furnace annealed slag gradually oxidizes the crushing surface immediately after the crushing treatment. Generally, however, when the crushing treatment is performed for about 3 months or more, deterioration of the reducing ability due to oxidation of the crushing surface becomes obvious. Therefore, the oxidation of the crushing surface does not proceed so much within one month after the crushing treatment, so that the corresponding reducing ability can be exhibited. Therefore, in the present invention, the blast furnace chilled slag within one month after being crushed is mixed with the crushed concrete waste. As a result, the blast furnace slow-cooled slag having a crushing surface (that is, a crushing surface that exists abundantly without oxidation of reducing sulfur) that has not yet been reduced after crushing can be mixed and contacted with the concrete waste material. It is possible to maximize the reduction ability of hexavalent chromium in the blast furnace chilled slag.
As the age of concrete waste increases, the bonding strength between cement hydrate and chromium weakens, and hexavalent chromium tends to elute. On the other hand, the blast furnace slow-cooled slag has a larger specific surface area as the crushed particle size is smaller, and the reducing ability of hexavalent chromium becomes higher. In that respect, the present invention can freely adjust the pulverized grain size of the blast furnace slow-cooled slag, and accordingly appropriately obtains the hexavalent chromium elution suppression effect according to the age of the concrete waste material (ease of elution of hexavalent chromium). be able to.

図1は、高炉徐冷スラグを粒径13mm以下に破砕し、(1)破砕直後のスラグ、(2)破砕して14日経過後のスラグ、(3)同28日経過後のスラグ、(4)同42日経過後のスラグ、(5)同56日経過後のスラグ、(4)同84日経過後のスラグについて、還元性硫黄量を調べた結果を示している。この試験では、高炉徐冷スラグ1質量部に対して水を15質量部添加し、6時間振とうした後に溶出した還元性硫黄量を評価した。
図1によれば、同じ破砕粒径であっても、破砕して1ヶ月以内の高炉徐冷スラグの溶出S量は1.8mg/g-slag以上であるが、それを過ぎると溶出S量の低下が進行し、特に3ヶ月近くなると大きく低下する。また、特に、破砕した直後の高炉徐冷スラグの溶出S量は1.95mg/g-slag程度であり、破砕からの期間が短いほど効果が大きいことを示している。
Figure 1 shows blast furnace slow-cooled slag crushed to a particle size of 13 mm or less, (1) slag immediately after crushing, (2) slag after crushing for 14 days, (3) slag after 28 days, (4) The results of examining the amount of reducing sulfur are shown for slag after the lapse of 42 days, (5) slag after the lapse of 56 days, and (4) slag after the lapse of 84 days. In this test, 15 parts by mass of water was added to 1 part by mass of the blast furnace gradually cooled slag, and the amount of reducing sulfur eluted after shaking for 6 hours was evaluated.
According to FIG. 1, even if the crushed particle size is the same, the leaching amount of blast furnace slow-cooled slag within one month after crushing is 1.8 mg / g-slag or more. In particular, the decrease is greatly reduced at about 3 months. In particular, the leaching amount of blast furnace slow-cooled slag immediately after crushing is about 1.95 mg / g-slag, indicating that the shorter the period from crushing, the greater the effect.

図2は、粒径10mm以下に破砕処理された直後の高炉徐冷スラグを、コンクリート廃材(粒径40mm以下に破砕処理されたコンクリート廃材)100質量部に対して3質量部、5質量部及び7質量部混合した路盤材(本発明例1)と、粒径10mm以下に破砕処理された後1ヶ月経過した高炉徐冷スラグを、コンクリート廃材(粒径40mm以下に破砕処理されたコンクリート廃材)100質量部に対して3質量部、5質量部及び7質量部混合した路盤材(本発明例2)と、粒径10mm以下に破砕処理された後4ヶ月経過した高炉徐冷スラグを、コンクリート廃材(粒径40mm以下に破砕処理されたコンクリート廃材)100質量部に対して3質量部、5質量部及び7質量部混合した路盤材(比較例)について、環境庁告示46号溶出試験によるCr溶出量を調べた結果を示している。なお、各Cr溶出量はN=5の平均値である。
図2によれば、粉砕してから4ヶ月経過した高炉徐冷スラグを用いた比較例においてもある程度の効果は得られるものの、この比較例に較べて本発明例1,2では格段に優れた効果(Crの溶出抑制効果)が得られている。
FIG. 2 shows 3 mass parts, 5 mass parts and blast furnace chilled slag immediately after being crushed to a particle size of 10 mm or less with respect to 100 mass parts of concrete waste material (concrete waste material crushed to a particle size of 40 mm or less) 7 mass parts mixed roadbed material (Invention Example 1) and blast furnace chilled slag 1 month after being crushed to a particle size of 10 mm or less, concrete waste (concrete waste material crushed to a particle size of 40 mm or less) A roadbed material (Invention Example 2) mixed with 3 parts by mass, 5 parts by mass and 7 parts by mass with respect to 100 parts by mass, and blast furnace chilled slag after 4 months after being crushed to a particle size of 10 mm or less, Regarding roadbed material (comparative example) mixed with 3 parts by mass, 5 parts by mass and 7 parts by mass with respect to 100 parts by mass of waste material (concrete waste material that has been crushed to a particle size of 40 mm or less) It shows the results of examining the Cr elution by the test. Each Cr elution amount is an average value of N = 5.
According to FIG. 2, although a certain degree of effect is obtained even in the comparative example using the blast furnace slow-cooled slag after 4 months from pulverization, the present invention examples 1 and 2 are remarkably superior to the comparative example. The effect (Cr elution suppression effect) is obtained.

本発明では、コンクリート廃材に対する高炉徐冷スラグの配合(混合)量は特に限定しないが、コンクリート廃材100質量部に対して2〜10質量部程度の割合で配合することが好ましい。コンクリート廃材100質量部に対する高炉徐冷スラグの割合が2質量部未満では、高炉徐冷スラグによる還元作用が不足するおそれがあり、一方、10質量部を超えても還元作用の面では問題はないが、コンクリート廃材からのCr溶出が少ない場合は、過剰な硫黄分によって溶出水がやや黄色を呈する可能性がある。   In the present invention, the blending (mixing) amount of the blast furnace slow cooling slag with respect to the concrete waste is not particularly limited, but it is preferably blended at a ratio of about 2 to 10 parts by mass with respect to 100 parts by mass of the concrete waste. If the ratio of the blast furnace slow-cooled slag to 100 parts by weight of the concrete waste is less than 2 parts by weight, the reducing action by the blast furnace slow-cooled slag may be insufficient, while if it exceeds 10 parts by weight, there is no problem in terms of the reducing action. However, when there is little Cr elution from a concrete waste material, there exists a possibility that elution water may show a little yellow with an excessive sulfur content.

コンクリート廃材及び高炉徐冷スラグの破砕処理後の粒度に特別な制限はないが、さきに述べたように、コンクリート廃材は一般に粒径40mm以下に破砕される。一方、高炉徐冷スラグは、粒径が小さいほど還元能力が高くなるので、高炉徐冷スラグとしては、粒径10mm以下の粒子の割合が30mass%以上となるような粒度に破砕処理されたものを、コンクリート廃材に混合することが好ましい。
高炉徐冷スラグをコンクリート廃材に混合する方法に特別な制限はなく、例えば、ミキサー、シューター、ショベル等を用いてバッチ式に混合してもよいし、ホッパー等に投入することで連続的に混合してもよい。
Although there is no particular restriction on the particle size of the concrete waste material and the blast furnace chilled slag after the crushing treatment, as described above, the concrete waste material is generally crushed to a particle size of 40 mm or less. On the other hand, since the blast furnace slow-cooled slag has a higher reducing ability as the particle size is smaller, the blast furnace slow-cooled slag is crushed to a particle size such that the proportion of particles having a particle size of 10 mm or less is 30 mass% or more. Is preferably mixed with concrete waste.
There is no particular restriction on the method of mixing the blast furnace slow-cooled slag into the concrete waste material. For example, it may be mixed batchwise using a mixer, shooter, excavator, etc., or continuously mixed by putting it into a hopper or the like. May be.

本発明において、作用効果の面で最も好ましい実施形態は破砕処理した直後の高炉徐冷スラグをコンクリート廃材に混合することであり、したがって、一連の製造工程(製造フロー)において、高炉徐冷スラグを破砕処理した後、コンクリート廃材に混合することが好ましい。また、同じ製造工程において、コンクリート廃材の破砕処理も行えば、路盤材等をより効率的に製造することが可能となる。   In the present invention, the most preferable embodiment in terms of the effect is to mix the blast furnace slow-cooled slag immediately after the crushing treatment with the concrete waste material. Therefore, in the series of manufacturing steps (production flow), the blast furnace slow-cooled slag is mixed. After crushing, it is preferable to mix with concrete waste. Further, if the concrete waste material is crushed in the same manufacturing process, the roadbed material and the like can be manufactured more efficiently.

図3は、本発明法の製造フローの一例を示したものであり、粒径40mm以下の路盤材を得る場合を示している。この実施形態では、ホッパー1から切り出されたコンクリート廃材は、破砕機2で破砕処理された後、篩い装置3で篩い分けされ、粒径40mm以下のコンクリート廃材が路盤材用としてホッパー4に貯留される。一方、粒径40mm超のコンクリート廃材は破砕機2に再送され、再度破砕処理される。また、ホッパー5から切り出された高炉徐冷スラグは、破砕機6で破砕処理された後、篩い装置7で篩い分けされ、所定粒径以下(例えば、40mm以下)の高炉徐冷スラグが路盤材用としてホッパー8に貯留される。一方、所定粒径超(例えば、40mm超)の高炉徐冷スラグは破砕機6に再送され、再度破砕処理される。なお、高炉徐冷スラグの破砕粒度を細かくしておけば、全量が篩い装置7を通過し、そのままホッパー8に貯留される。そして、ホッパー4,8から切り出されたコンクリート廃材と高炉徐冷スラグが混合機9に装入され、混合されることにより路盤材が得られる。   FIG. 3 shows an example of a production flow of the method of the present invention, and shows a case where a roadbed material having a particle size of 40 mm or less is obtained. In this embodiment, the concrete waste material cut out from the hopper 1 is crushed by the crusher 2, and then sieved by the sieving device 3, and the concrete waste material having a particle size of 40 mm or less is stored in the hopper 4 for roadbed material. The On the other hand, the concrete waste having a particle size of more than 40 mm is retransmitted to the crusher 2 and is crushed again. Further, the blast furnace slow-cooled slag cut out from the hopper 5 is crushed by the crusher 6, and then sieved by the sieving device 7, and the blast furnace slow-cooled slag having a predetermined particle size or less (for example, 40 mm or less) is used as the roadbed material. It is stored in the hopper 8 for use. On the other hand, the blast furnace slow-cooled slag exceeding a predetermined particle size (for example, more than 40 mm) is retransmitted to the crusher 6 and crushed again. If the pulverized grain size of the blast furnace slow-cooled slag is made fine, the entire amount passes through the sieving device 7 and is stored in the hopper 8 as it is. Then, the concrete waste material cut out from the hoppers 4 and 8 and the blast furnace slow cooling slag are charged into the mixer 9 and mixed to obtain a roadbed material.

本発明では、一連の製造工程において、高炉徐冷スラグを破砕処理した後、コンクリート廃材に混合する場合、高炉徐冷スラグを水を含ませた状態で破砕処理することにより、その水分中にスラグの還元性硫黄が一部溶解し、コンクリート廃材との混合と同時に速やかに6価クロムの還元作用を及ぼすことができるため、初期における6価クロム溶出をより効果的に抑制できる。
高炉徐冷スラグに水を含ませた形態としては、高炉徐冷スラグを破砕した際に、その破砕面の還元性硫黄の少なくとも一部が水に溶解するような形態であればよく、したがって、スラグ粒やスラグ塊内に水が吸収された形態、スラグ粒やスラグ塊の表面に水が付着した形態(表面が水に濡れた状態)のいずれでもよいが、硫黄分の流出を防止するためには、水が流出しない程度に水を含ませた状態であることが望ましい。
高炉徐冷スラグに水を含ませるには、散水、水中への浸漬など適宜な方法を採ることができる。また、高炉徐冷スラグに水を含ませる時期などについても特別な制限はない。
In the present invention, in a series of manufacturing processes, when blast furnace chilled slag is crushed and then mixed with concrete waste, blast furnace chilled slag is crushed in a state of containing water, so that slag is contained in the water. The reductive sulfur is partly dissolved, and the reducing action of hexavalent chromium can be effected at the same time as mixing with the concrete waste material, so that the elution of hexavalent chromium in the initial stage can be more effectively suppressed.
The form in which water is contained in the blast furnace slow-cooled slag may be any form in which at least a part of the reducing sulfur on the crushed surface is dissolved in water when the blast furnace slow-cooled slag is crushed. Either slag grains or slag lump water is absorbed, or water is attached to the surface of slag grains or slag lump (the surface is wet with water), but to prevent the outflow of sulfur In this case, it is desirable that the water is contained in such a degree that the water does not flow out.
In order to include water in the blast furnace slow cooling slag, an appropriate method such as watering or immersion in water can be employed. Moreover, there is no special restriction | limiting also regarding the time of including water in a blast furnace slow cooling slag.

以上述べた本発明の製造方法により製造される路盤材等は、コンクリート廃材を主体とし、且つ高炉徐冷スラグを含む路盤材等であって、破砕処理されたコンクリート廃材に、破砕処理されてから1ヶ月以内の高炉徐冷スラグを混合して得られた路盤材である。さきに述べたようにこの路盤材等は、コンクリート廃材中の6価クロムが効果的に還元され、コンクリート廃材からの6価クロムの溶出が高度に抑制される。   The roadbed material manufactured by the manufacturing method of the present invention described above is mainly a concrete waste material and is a roadbed material including a blast furnace slow-cooled slag, and after being crushed into the crushed concrete waste material. It is a roadbed material obtained by mixing blast furnace slow cooling slag within one month. As described above, in this roadbed material and the like, hexavalent chromium in the concrete waste material is effectively reduced, and elution of hexavalent chromium from the concrete waste material is highly suppressed.

高炉徐冷スラグを粒径13mm以下に破砕し、(1)破砕直後のスラグ、(2)破砕して14日経過後のスラグ、(3)同28日経過後のスラグ、(4)同42日経過後のスラグ、(5)同56日経過後のスラグ、(4)同84日経過後のスラグについて、還元性硫黄量を調べた結果を示すグラフBlast furnace slow-cooled slag is crushed to a particle size of 13 mm or less, (1) Slag immediately after crushing, (2) Slag after crushing after 14 days, (3) Slag after 28 days, (4) After 42 days Slag, (5) Slag after 56 days, (4) Graph showing the results of examining the amount of reducing sulfur for slag after 84 days 本発明法で得られた路盤材と従来法で得られた路盤材について、環境庁告示46号溶出試験によりCr溶出量を調べた結果を示すグラフThe graph which shows the result of having investigated the amount of Cr elution by the environmental agency notification 46 elution test about the roadbed material obtained by this invention method, and the roadbed material obtained by the conventional method 本発明法の製造フローの一例を示す説明図Explanatory drawing which shows an example of the manufacturing flow of this invention method

符号の説明Explanation of symbols

1,4,5,8 ホッパー
2,6 破砕機
3,7 篩い装置
9 混合機
1,4,5,8 Hopper 2,6 Crusher 3,7 Screening device 9 Mixer

Claims (5)

コンクリート廃材を破砕処理して路盤材及び/又は土工材を製造する方法であって、
破砕処理されたコンクリート廃材に、破砕処理されてから1ヶ月以内の高炉徐冷スラグを混合することを特徴とする、コンクリート廃材からの路盤材等の製造方法。
A method for producing a roadbed material and / or earthwork material by crushing a waste concrete material,
A method for producing roadbed material or the like from concrete waste, characterized by mixing crushed concrete waste with blast furnace chilled slag within one month of being crushed.
コンクリート廃材100質量部に対して高炉徐冷スラグを2〜10質量部の割合で混合することを特徴とする、請求項1に記載のコンクリート廃材からの路盤材等の製造方法。   The method for producing a roadbed material or the like from concrete waste according to claim 1, wherein the blast furnace slow cooling slag is mixed at a ratio of 2 to 10 parts by weight with respect to 100 parts by weight of the concrete waste. コンクリート廃材に、粒径10mm以下の粒子の割合が30mass%以上である高炉徐冷スラグを混合することを特徴とする、請求項1又は2に記載のコンクリート廃材からの路盤材等の製造方法。   The method for producing roadbed material or the like from concrete waste according to claim 1 or 2, characterized in that blast furnace slow cooling slag in which the proportion of particles having a particle size of 10 mm or less is 30 mass% or more is mixed with the concrete waste. 一連の製造工程において、高炉徐冷スラグを破砕処理した後、コンクリート廃材に混合することを特徴とする、請求項1〜3のいずれかに記載のコンクリート廃材からの路盤材等の製造方法。   In a series of manufacturing processes, after crushing a blast furnace slow cooling slag, it mixes with a concrete waste material, The manufacturing method of the roadbed material etc. from the concrete waste material in any one of Claims 1-3 characterized by the above-mentioned. 高炉徐冷スラグを水を含んだ状態で破砕処理することを特徴とする、請求項4に記載のコンクリート廃材からの路盤材等の製造方法。   The method for producing a roadbed material or the like from waste concrete material according to claim 4, wherein the blast furnace slow-cooled slag is crushed in a state containing water.
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JPH0551907A (en) * 1991-08-26 1993-03-02 Nisshin Steel Co Ltd Manufacture of composite roadbed material
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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2010012456A (en) * 2008-06-05 2010-01-21 Jfe Steel Corp Reconditioned sand or earthwork material, and its manufacturing method
JP2017023993A (en) * 2015-03-31 2017-02-02 Jfeスチール株式会社 Treating agent and treating method for hexavalent chromium, roadbed material, and method for construction of the material
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