JP2001342625A - Preboring construction method preventing elution of chromium - Google Patents

Preboring construction method preventing elution of chromium

Info

Publication number
JP2001342625A
JP2001342625A JP2001096908A JP2001096908A JP2001342625A JP 2001342625 A JP2001342625 A JP 2001342625A JP 2001096908 A JP2001096908 A JP 2001096908A JP 2001096908 A JP2001096908 A JP 2001096908A JP 2001342625 A JP2001342625 A JP 2001342625A
Authority
JP
Japan
Prior art keywords
chromium
elution
cement
hexavalent chromium
sodium
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
JP2001096908A
Other languages
Japanese (ja)
Inventor
Naoki Maeda
直己 前田
Kazuhiko Sato
和彦 佐藤
Hidenori Kobayashi
英紀 小林
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Maeta Techno Research Inc
Maeta Concrete Industry Ltd
Original Assignee
Maeta Techno Research Inc
Maeta Concrete Industry Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Maeta Techno Research Inc, Maeta Concrete Industry Ltd filed Critical Maeta Techno Research Inc
Priority to JP2001096908A priority Critical patent/JP2001342625A/en
Publication of JP2001342625A publication Critical patent/JP2001342625A/en
Pending legal-status Critical Current

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B28/00—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements
    • C04B28/02—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements containing hydraulic cements other than calcium sulfates
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2103/00—Function or property of ingredients for mortars, concrete or artificial stone
    • C04B2103/0004—Compounds chosen for the nature of their cations
    • C04B2103/0013—Iron group metal compounds
    • C04B2103/0014—Fe
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2103/00—Function or property of ingredients for mortars, concrete or artificial stone
    • C04B2103/0004—Compounds chosen for the nature of their cations
    • C04B2103/0017—Refractory metal compounds
    • C04B2103/0018—Cr
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2103/00—Function or property of ingredients for mortars, concrete or artificial stone
    • C04B2103/0068—Ingredients with a function or property not provided for elsewhere in C04B2103/00
    • C04B2103/0096—Reducing agents
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2111/00—Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
    • C04B2111/00474—Uses not provided for elsewhere in C04B2111/00
    • C04B2111/00732—Uses not provided for elsewhere in C04B2111/00 for soil stabilisation
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2111/00—Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
    • C04B2111/00474—Uses not provided for elsewhere in C04B2111/00
    • C04B2111/00767—Uses not provided for elsewhere in C04B2111/00 for waste stabilisation purposes
    • Y—GENERAL 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
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
    • Y02W30/00—Technologies for solid waste management
    • Y02W30/50—Reuse, recycling or recovery technologies
    • Y02W30/91—Use of waste materials as fillers for mortars or concrete

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Ceramic Engineering (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Inorganic Chemistry (AREA)
  • Materials Engineering (AREA)
  • Structural Engineering (AREA)
  • Organic Chemistry (AREA)
  • Placing Or Removing Of Piles Or Sheet Piles, Or Accessories Thereof (AREA)
  • Soil Conditioners And Soil-Stabilizing Materials (AREA)

Abstract

PROBLEM TO BE SOLVED: To provide a preboring construction method having excellent effect for preventing the elution of chromium capable of making the effect last for a long time. SOLUTION: This preboring construction method prevents the elution of chromium using pozzolan substance or porous silicate and cement milk to which a reducing agent is added.

Description

【発明の詳細な説明】DETAILED DESCRIPTION OF THE INVENTION

【０００１】[0001]

【発明の属する技術分野】建築や土木の基礎工事等では
基礎杭(パイル)を地盤に埋設して固定する際に、プレボ
ーリング工法が広く採用されているが、本発明はこのプ
レボーリング工法において、クロムの溶出を防止し、長
期間その溶出防止効果を維持することができる工法に関
する。The pre-boring method is widely used when burying and fixing a foundation pile (pile) in the ground in construction or civil engineering foundation work, etc., but the present invention relates to this pre-boring method. And a method for preventing chromium elution and maintaining the elution prevention effect for a long time.

【０００２】[0002]

【従来の技術】プレボーリング工法はプレオーガー埋め
込み工法とも呼ばれており、その概要は、基礎工事で地
盤にパイルを施工する際に、先ずアースオーガーを使用
して地盤に所定の深さの掘削孔を形成し、この掘削孔に
アースオーガーのヘッドからセメントミルク(充填液)を
注入しながらアースオーガーを引き上げ、このセメント
ミルクが注入された掘削孔にパイルを建て込んで定着さ
せる工法であり、パイルを打撃して地盤に打ち込む打撃
工法等に比較して騒音や振動等が格段に少ない利点があ
り、騒音公害等の心配がないため特に市街地では広く実
施されている。2. Description of the Related Art The pre-boring method is also called a pre-auger embedding method. An outline of the method is that when a pile is laid on the ground in a foundation work, an earth auger is first used to excavate a predetermined depth into the ground. This is a construction method in which the earth auger is pulled up while pouring cement milk (filling liquid) from the head of the earth auger into the borehole, and a pile is built and fixed in the borehole into which the cement milk has been injected. It has the advantage of significantly less noise and vibration compared to the impact method of hitting the ground and hitting it into the ground, and is widely practiced especially in urban areas because there is no concern about noise pollution and the like.

【０００３】[0003]

【発明が解決しようとする課題】しかしながら、このプ
レボーリング工法では掘削孔内に注入されたセメントミ
ルクが硬化するまでにかなりの時間を要し、この間にセ
メントから微量の六価クロムが溶出する可能性があっ
た。すなわち、プレボーリング工法では、使用されるセ
メントミルクが杭の埋め込み時に六価クロムを含んだオ
ーバーフローした泥水として流出する虞れがあり、ある
いは水比が過大なセメントミルクではブリージングによ
って六価クロムを含む分離水を発生させる可能性があ
る。セメントには僅かながら六価クロムが含まれてお
り、その含有量が２０ppm程度に及ぶ場合もある。六価
クロムは水溶性が高いのでこのようなセメントを使用す
るとセメントが硬化するまでの間に六価クロムが溶出し
て土壌を汚染する懸念がある。However, in this pre-boring method, it takes a considerable amount of time for the cement milk injected into the borehole to harden, during which time a small amount of hexavalent chromium can be eluted from the cement. There was sex. That is, in the pre-boring method, there is a possibility that the used cement milk may flow out as an overflowing muddy water containing hexavalent chromium at the time of embedding the pile, or the cement milk having an excessive water ratio contains hexavalent chromium by breathing. May generate separated water. Cement contains hexavalent chromium slightly, and its content may reach about 20 ppm. Since hexavalent chromium has high water solubility, use of such a cement may cause hexavalent chromium to elute before the cement hardens and contaminate the soil.

【０００４】このようなクロムの溶出防止方法として、
特開昭48-83114号公報にはセメントに硫酸第一鉄等の還
元剤を添加することによって六価クロムを難溶性の三価
クロムに還元し、コンクリート中に閉じ込める技術が開
示されている。ところが、六価クロムはｐＨ３以下の強
酸性下では強力な酸化作用を有するので還元剤の存在に
よって容易に還元されて三価クロムになるが、ｐＨ３〜
７の酸性から中性に至る領域ではクロムの還元率が急激
に低下するので、六価クロムが十分に還元されず、その
溶出を十分に防止できない可能性がある。特に泥炭等の
高有機質土や、雨水によって溶出された酸性土壌では、
六価クロム溶出の懸念がある。さらに、硫酸第一鉄は空
気中の酸素と容易に反応して酸化鉄となり還元力を失
い、長期的に還元力を維持できないので、クロム溶出防
止の効果が短期間に失われると云う問題がある。As a method for preventing the elution of chromium,
JP-A-48-83114 discloses a technique in which hexavalent chromium is reduced to hardly soluble trivalent chromium by adding a reducing agent such as ferrous sulfate to cement, and confined in concrete. However, hexavalent chromium has a strong oxidizing action under strong acidity of pH 3 or less, and is easily reduced to trivalent chromium by the presence of a reducing agent.
Since the reduction ratio of chromium sharply decreases in the range from acidity to neutrality of 7, hexavalent chromium is not sufficiently reduced, and elution thereof may not be sufficiently prevented. Especially in high organic soils such as peat, or acidic soils eluted by rainwater,
There is a concern about elution of hexavalent chromium. In addition, ferrous sulfate easily reacts with oxygen in the air to form iron oxide, which loses reducing power, and cannot maintain reducing power in the long term, so that the effect of preventing chromium elution is lost in a short time. is there.

【０００５】本発明は、プレボーリング工法における従
来のこのような問題点を解決したものであり、酸性土壌
においてもクロムの溶出を確実に抑制し、この抑制効果
を長期間持続することができ、さらにオーバーフローし
た泥水やブリージングがあってもこれらに六価クロムが
環境基準濃度以上含まれることのないプレボーリング工
法を提供することを目的とする。The present invention has solved the above-mentioned conventional problems in the pre-boring method, and can surely suppress the elution of chromium even in an acidic soil, and can maintain this suppressing effect for a long time. It is still another object of the present invention to provide a pre-boring method in which hexavalent chromium is not contained at an environmental standard concentration or more even when overflowing muddy water or breathing occurs.

【０００６】[0006]

【課題を解決するための手段】すなわち、本発明によれ
ば以下の構成からなるプレボーリング工法が提供され
る。 （１）ポゾラン物質ないし多孔質ケイ酸塩と、還元剤と
を添加したセメントミルクを用いることによりクロムの
溶出を防止したことを特徴とするプレボーリング工法。 （２）ポゾラン物質ないし多孔質ケイ酸塩が、シリカフ
ュームや籾殻灰などのシリカ質ポゾラン物質、ゼオライ
ト、高炉スラグ、または粘土質ポゾランなどの多孔質ケ
イ酸塩から選ばれる少なくとも一種である上記(1)のプ
レボーリング工法。 （３）還元剤が、硫酸第一鉄、塩化第一鉄などの第一鉄
塩、亜硫酸ナトリウムなどの亜硫酸塩、または亜硝酸ナ
トリウムなどの亜硝酸塩、または硫化アンモニウム、硫
化ナトリウム等の硫化物、チオ硫酸ナトリウム等のチオ
硫酸塩である上記(1)または(2)のプレボーリング工法。That is, according to the present invention, there is provided a pre-boring method comprising the following constitution. (1) A pre-boring method wherein chromium elution is prevented by using cement milk to which a pozzolanic substance or a porous silicate and a reducing agent are added. (2) The above-mentioned (1), wherein the pozzolanic substance or the porous silicate is at least one selected from a siliceous pozzolanic substance such as silica fume and rice husk ash, a porous silicate such as zeolite, blast furnace slag, or clayey pozzolan. ) Pre-boring method. (3) ferrous salts such as ferrous sulfate and ferrous chloride; sulfites such as sodium sulfite; nitrites such as sodium nitrite; or sulfides such as ammonium sulfide and sodium sulfide; The preboring method according to the above (1) or (2), which is a thiosulfate such as sodium thiosulfate.

【０００７】以下、本発明を実施例と共に詳細に説明す
る。本発明のプレボーリング工法は、ポゾラン物質ない
し多孔質ケイ酸塩と、還元剤とを添加したセメントミル
クを用いることによりクロムの溶出を防止したことを特
徴とするものである。本発明において用いるセメントの
種類は限定されない。普通ポルトランドセメント、早強
ポルトランドセメント、中庸熱ポルトランドセメント等
のポルトランドセメント系セメント、または、ポルトラ
ンド系セメントにフライアッシュ、高炉水砕スラグやシ
リカを混合したフライアッシュセメント、高炉セメン
ト、シリカセメントのような混合セメントなどを用いる
ことができる。Hereinafter, the present invention will be described in detail with reference to examples. The preboring method of the present invention is characterized in that chromium elution is prevented by using cement milk to which a pozzolanic substance or a porous silicate and a reducing agent are added. The type of cement used in the present invention is not limited. Portland cement-based cement such as ordinary Portland cement, early-strength Portland cement, moderately heated Portland cement, etc. A suitable mixed cement or the like can be used.

【０００８】ポゾラン物質ないし多孔質ケイ酸塩は、シ
リカフュームや籾殻灰などのシリカ質ポゾラン物質、粘
土質ポゾラン、あるいはゼオライト、高炉(溶融)スラグ
などの多孔質ケイ酸塩であり、これらから選ばれる少な
くとも一種が用いられる。籾殻灰などはシリカ質ポゾラ
ンであると共に多孔質ケイ酸塩であり、クロムなどの重
金属イオンを吸着する作用を有する。ここで使用するポ
ゾラン物質の比表面積は５０m2/g以上、より好ましくは
１００m2/g以上であり、また使用する多孔質ケイ酸塩の
粉末度はブレーン4000cm2/g以上、より好ましくはブレ
ーン8000cm2/g以上であることが望ましい。比表面積や
粉末度が小さいと、これら添加剤のクロム固定能力が小
さくなり、添加量が多くなり経済的でない。The pozzolanic substance or the porous silicate is a silicic pozzolanic substance such as silica fume or rice husk ash, a clayey pozzolan, or a porous silicate such as zeolite or blast furnace (melted) slag. At least one is used. Rice husk ash and the like are both siliceous pozzolans and porous silicates, and have an action of adsorbing heavy metal ions such as chromium. The specific surface area of the pozzolanic substance used here is at least 50 m 2 / g, more preferably at least 100 m 2 / g, and the fineness of the porous silicate used is at least 4000 cm 2 / g, more preferably at least Desirably, it is 8000 cm 2 / g or more. If the specific surface area or the fineness is small, the chromium fixing ability of these additives becomes small, and the added amount becomes large, which is not economical.

【０００９】還元剤としては、硫酸第一鉄、塩化第一鉄
などの第一鉄塩、亜硫酸ナトリウムなどの亜硫酸塩、ま
たは亜硝酸ナトリウムなどの亜硝酸塩、または硫化アン
モニウム、硫化ナトリウム等の硫化物、チオ硫酸ナトリ
ウム等のチオ硫酸塩が用いられる。このうち硫酸第一
鉄、硫酸ナトリウム、チオ硫酸ナトリウムは安価であり
十分な還元力を有するので好ましい。As the reducing agent, ferrous salts such as ferrous sulfate and ferrous chloride; sulfites such as sodium sulfite; nitrites such as sodium nitrite; and sulfides such as ammonium sulfide and sodium sulfide And thiosulfates such as sodium thiosulfate are used. Of these, ferrous sulfate, sodium sulfate, and sodium thiosulfate are preferable because they are inexpensive and have sufficient reducing power.

【００１０】先に述べたように、六価クロムは水溶性が
高いのでセメントに含まれている場合には、その硬化前
は勿論のことセメント硬化後も僅かではあるがイオン化
して溶出する。一方、水酸化クロムなどの三価クロムは
難溶性であり、特にセメントのような高ｐＨの環境下で
は容易に沈殿するので、セメントが硬化する前でも系外
に溶出することは殆どない。しかし、水酸化クロム等と
して固定された三価クロムでも周囲のｐＨがアルカリ性
から中性ないし酸性に近づくにつれて次第に陽イオン化
し易くなり、系外に溶出する可能性がある。従って、土
壌中に酸化物質が存在すると三価クロムが酸化されて六
価クロムになる懸念がある。泥炭などの酸性物質を含む
土壌はこの虞が高い。As described above, hexavalent chromium is highly water-soluble and, when contained in cement, is slightly ionized and eluted before and after hardening of the cement. On the other hand, trivalent chromium such as chromium hydroxide is hardly soluble, and easily precipitates particularly in a high pH environment such as cement, so that it hardly elutes out of the system even before the cement hardens. However, even with trivalent chromium fixed as chromium hydroxide or the like, as the surrounding pH approaches from alkaline to neutral or acidic, it becomes easier to cation gradually and may be eluted out of the system. Therefore, when an oxidizing substance is present in soil, there is a concern that trivalent chromium is oxidized to hexavalent chromium. Soil containing acidic substances such as peat is highly likely to have this risk.

【００１１】ところが、本発明のように、硫酸第一鉄な
どの還元剤と共に、シリカフュームや籾殻灰などのシリ
カ質ポゾラン物質、粘土質ポゾラン、あるいはゼオライ
ト、高炉スラグなどの多孔質ケイ酸塩を含むものは、こ
のポゾラン物資ないし多孔質ケイ酸塩が陽イオンのクロ
ムを吸着固定するのでクロムの溶出を防止することがで
きる。とくに、酸性土壌においてセメント硬化後のクロ
ムの再溶出を効果的に防止することができる。また、高
炉スラグなどある種の溶融スラグは、硫化物など六価ク
ロムを長期的に還元する成分を含むものがあり、これを
他のポゾラン物質又は多孔質ケイ酸塩と併用して用いる
ことも望ましい用い方の一つである。さらに、本法では
硫酸第一鉄等のすみやかに還元力を有する物質を併用す
るので、オーバーフローした泥水やブリージングがあっ
てもこれらに六価クロムが環境基準濃度以上含まれるこ
とがない。However, as in the present invention, a siliceous pozzolanic substance such as silica fume or rice husk ash, a clayey pozzolan, or a porous silicate such as zeolite or blast furnace slag is contained together with a reducing agent such as ferrous sulfate. In this case, since the pozzolanic substance or the porous silicate adsorbs and fixes cation chromium, elution of chromium can be prevented. In particular, re-elution of chromium after cement hardening can be effectively prevented in acidic soil. In addition, some types of molten slag, such as blast furnace slag, contain components that reduce hexavalent chromium, such as sulfides, over a long period of time, and may be used in combination with other pozzolanic substances or porous silicates. This is one of the preferred uses. Furthermore, in the present method, since a substance having a quick reducing power such as ferrous sulfate is used in combination, even if there is overflowing muddy water or breathing, hexavalent chromium will not be contained in an environmental standard concentration or more.

【００１２】[0012]

【実施例１】市販の普通ポルトランドセメント(太平洋セ
メント社製品)を用い、泥炭(北海道美唄産)、硫酸第一鉄
(堺化学工業社製品)、籾殻灰(前田先端技術研究所製:比
表面積150ｍ2/g)、高炉スラグ(日鉄セメント社製品:フ゛レーン80
00)を表１のように配合し、混練時を０分として、混練
時からの時間経過と全クロムの溶出量を測定した。この
クロム量の測定はジフェニルカルバジド吸光光度法(JIS
K 0102)に基づいて行った。この結果を表２に示した。
硫酸第一鉄のみを添加した比較例１では、混練１週間目
ではクロムは検出されないが、４週以後はクロムの再溶
出が認められた。一方、硫酸第一鉄と共に籾殻灰または
高炉スラグを添加した本発明の実施試料(No.１,２)で
は、混練４週目までクロムの溶出は認められず、混練８
週目および１２週目のクロム溶出量も少ない。[Example 1] Using commercially available ordinary Portland cement (product of Taiheiyo Cement Co.), peat (from Bibai, Hokkaido), ferrous sulfate
(Product of Sakai Chemical Industry Co., Ltd.), rice husk ash (manufactured by Maeda Advanced Technology Laboratory: specific surface area 150 m 2 / g), blast furnace slag (product of Nippon Cement Co., Ltd.
00) were blended as shown in Table 1, and the kneading time was set to 0 minutes, and the elapsed time from the kneading time and the elution amount of all chromium were measured. The measurement of the amount of chromium is carried out by diphenylcarbazide absorption spectrophotometry (JIS
K0102). The results are shown in Table 2.
In Comparative Example 1 in which only ferrous sulfate was added, chromium was not detected in the first week of kneading, but re-elution of chromium was observed after 4 weeks. On the other hand, in the working samples (Nos. 1 and 2) of the present invention in which rice husk ash or blast furnace slag was added together with ferrous sulfate, no elution of chromium was observed until the fourth week of kneading.
The amount of chromium eluted at week and week 12 is also small.

【００１３】[0013]

【表１】 [Table 1]

【００１４】[0014]

【表２】 [Table 2]

【００１５】[0015]

【実施例２】実施例１と同じセメント、硫酸第一鉄、高
炉スラグ微粉末を用い、水セメント比６０％および１０
０％のセメントミルクを調整した。なお、硫酸第一鉄お
よび高炉スラグ微粉末の添加量は使用したセメントに対
して各々０.５重量部、３重量部内割で添加した。ポリ
エチレンチューブに流し込んだセメントミルクを、２０
度恒温室内で放置し、７日、１４日、２８日材齢におけ
る圧縮強度と、材齢７日、２８日、９１日における硬化
体からの六価クロム溶出量を環境庁告示第４６号に従っ
て測定した。またブリージング中の六価クロム濃度をジ
フェニルカルバジド吸光光度法（JIS K 0102）に準じて
測定した。この結果を表３に示した。Example 2 The same cement, ferrous sulfate, and fine powder of blast furnace slag as in Example 1 were used.
0% cement milk was prepared. The amounts of ferrous sulfate and blast furnace slag fine powder were 0.5 parts by weight and 3 parts by weight, respectively, based on the cement used. Add the cement milk poured into the polyethylene tube to 20
The specimen was allowed to stand in a constant temperature room, and the compressive strength at the age of 7 days, 14 days and 28 days, and the amount of hexavalent chromium eluted from the cured product at the age of 7 days, 28 days and 91 days were determined according to the notification of the Environment Agency No. 46. It was measured. The hexavalent chromium concentration during the breathing was measured according to the diphenylcarbazide absorption spectrophotometry (JIS K 0102). The results are shown in Table 3.

【００１６】表３に示すように、本発明の方法に従い添
加剤（硫酸第一鉄と高炉スラグ微粉末）を加えたセメン
トミルクを用いたものは、硬化体からの六価クロム溶出
とブリージング中の六価クロム濃度は定量限界以下とな
った。高炉スラグ微粉末のみを添加した場合にも硬化体
からの六価クロム溶出は確認できなかったが、ブリージ
ング中の六価クロム濃度は高炉スラグ微粉末のみでは基
準値以下とすることはできなかった。また、硫酸第一鉄
０.５％添加のみでも、硬化体からの六価クロム溶出お
よびブリージング中の六価クロム濃度はかなり抑えられ
るが、ブリージング中の六価クロム濃度は基準値を超え
ており、かつ土質分が混入したりセメント中の六価クロ
ム濃度が高い場合には、実施例１のように基準値以下と
ならない可能性も考えられる。As shown in Table 3, in the case of using cement milk to which additives (ferrous sulfate and blast furnace slag fine powder) were added according to the method of the present invention, hexavalent chromium was eluted from the cured product and the Was below the limit of quantification. Even when only blast furnace slag fine powder was added, elution of hexavalent chromium from the cured product could not be confirmed, but hexavalent chromium concentration during breathing could not be reduced below the reference value only with blast furnace slag fine powder . The addition of only 0.5% ferrous sulfate can significantly suppress the elution of hexavalent chromium from the cured product and the hexavalent chromium concentration during breathing, but the hexavalent chromium concentration during breathing exceeds the standard value. When soil content is mixed or the hexavalent chromium concentration in the cement is high, there is a possibility that the value does not fall below the reference value as in Example 1.

【００１７】[0017]

【表３】 [Table 3]

【００１８】[0018]

【実施例３】表４に示す、砂質土、粘性土、関東ロー
ム、シラスの四種類の土壌について、実施例１と同様の
セメントミルクを混合し、その圧縮強度、六価クロム溶
出量、ブリージング率を測定した。土質分のセメントミ
ルクに対する混合量は容積比で２５％、５０％とした。
なお、ブリージング水中の六価クロム濃度は規格(JIS K
0102)に準じ、ジフェニルカルバジドによる被検液の六
価クロム濃度標準系列を作成し、着色の度合いに応じ
て、０.５mg/l単位でその濃度範囲を判定した。その結
果を表５〜表８に示す。添加剤（硫酸第一鉄0.5％、高炉
スラグ微粉末3％）を添加した硬化体およびブリージン
グ水中の六価クロム濃度は基準値以下であり、硬化体の
強度においても優れており、土質にかかわらず六価クロ
ムの溶出を防止する効果を有することが明らかとなっ
た。またブリージングのない場合でも、これを分離した
上澄み液中に基準値以上の六価クロムは検出されなかっ
た。Example 3 For the four types of soils shown in Table 4, sandy soil, cohesive soil, Kanto loam, and shirasu, the same cement milk as in Example 1 was mixed, and its compressive strength, hexavalent chromium elution amount, The breathing rate was measured. The mixing amount of the soil to the cement milk was 25% and 50% by volume.
The hexavalent chromium concentration in breathing water is based on standard (JIS K
[0102] A standard series of hexavalent chromium concentration of the test solution with diphenylcarbazide was prepared according to the above, and the concentration range was determined in units of 0.5 mg / l according to the degree of coloring. The results are shown in Tables 5 to 8. The concentration of hexavalent chromium in the cured product and the breathing water to which additives (ferrous sulfate 0.5%, blast furnace slag fine powder 3%) is added is below the reference value, and the strength of the cured product is excellent. It has been found that it has the effect of preventing the elution of hexavalent chromium. Even when no breathing was found, hexavalent chromium exceeding the reference value was not detected in the supernatant liquid from which this was separated.

【００１９】[0019]

【表４】 [Table 4]

【００２０】[0020]

【表５】 [Table 5]

【００２１】[0021]

【表６】 [Table 6]

【００２２】[0022]

【表７】 [Table 7]

【００２３】[0023]

【表８】 [Table 8]

【００２４】[0024]

【発明の効果】本発明のプレボーリング工法によれば、
クロムの還元率が低下する弱酸性下ないし中性下の土壌
においてもクロムの溶出を効果的に抑制することがで
き、この抑制効果がセメント硬化後も長期的に持続す
る。また、使用する泥水がブリージングを起こしたり、
またはオーバーフローして現場周辺に流出した場合に
も、周囲地盤が六価クロムによって汚染されることのな
い既製杭の埋め込み工法を提供できる。According to the pre-boring method of the present invention,
Chromium elution can be effectively suppressed even in a weakly acidic or neutral soil where the reduction ratio of chromium is reduced, and this suppression effect is maintained for a long time after cement hardening. Also, the mud used may cause breathing,
Alternatively, even when overflow occurs and flows to the vicinity of the site, a method of embedding a ready-made pile that does not contaminate the surrounding ground with hexavalent chromium can be provided.

───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.7 識別記号 ＦＩ テーマコート゛(参考） // Ｃ０９Ｋ 103:00 Ｃ０９Ｋ 103:00 (72)発明者 佐藤 和彦 山形県酒田市上本町６番７号 株式会社前 田先端技術研究所内 (72)発明者 小林 英紀 山形県酒田市上本町６番７号 株式会社前 田先端技術研究所内──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. 7 Identification symbol FI Theme coat ゛ (Reference) // C09K 103: 00 C09K 103: 00 (72) Inventor Kazuhiko Sato 6-7 Uehonmachi, Sakata City, Yamagata Prefecture Maeda Advanced Technology Laboratory Co., Ltd. (72) Inventor Hideki Kobayashi 6-7 Uehonmachi, Sakata City, Yamagata Prefecture Maeda Advanced Technology Laboratory Co., Ltd.

Claims (3)

【特許請求の範囲】[Claims] 【請求項１】 ポゾラン物質ないし多孔質ケイ酸塩と、
還元剤とを添加したセメントミルクを用いることにより
クロムの溶出を防止したことを特徴とするプレボーリン
グ工法。1. A pozzolanic substance or a porous silicate,
A pre-boring method characterized by preventing the elution of chromium by using cement milk to which a reducing agent has been added. 【請求項２】 ポゾラン物質ないし多孔質ケイ酸塩が、
シリカフュームや籾殻灰などのシリカ質ポゾラン物質、
ゼオライト、高炉スラグ、または粘土質ポゾランなどの
多孔質ケイ酸塩から選ばれる少なくとも一種である請求
項１のプレボーリング工法。2. The method of claim 1, wherein the pozzolanic substance or the porous silicate is
Silica pozzolanic substances such as silica fume and rice husk ash,
2. The pre-boring method according to claim 1, wherein the method is at least one selected from the group consisting of zeolite, blast furnace slag, and porous silicate such as clayey pozzolan. 【請求項３】 還元剤が、硫酸第一鉄、塩化第一鉄など
の第一鉄塩、亜硫酸ナトリウムなどの亜硫酸塩、または
亜硝酸ナトリウムなどの亜硝酸塩、または硫化アンモニ
ウム、硫化ナトリウム等の硫化物、チオ硫酸ナトリウム
等のチオ硫酸塩である請求項１または２のプレボーリン
グ工法。3. The reducing agent is a ferrous salt such as ferrous sulfate or ferrous chloride; a sulfite such as sodium sulfite; a nitrite such as sodium nitrite; or a sulfide such as ammonium sulfide or sodium sulfide. The pre-boring method according to claim 1 or 2, which is a thiosulfate such as sodium thiosulfate.
JP2001096908A 2000-03-30 2001-03-29 Preboring construction method preventing elution of chromium Pending JP2001342625A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2001096908A JP2001342625A (en) 2000-03-30 2001-03-29 Preboring construction method preventing elution of chromium

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
JP2000093446 2000-03-30
JP2000-93446 2000-03-30
JP2001096908A JP2001342625A (en) 2000-03-30 2001-03-29 Preboring construction method preventing elution of chromium

Publications (1)

Publication Number Publication Date
JP2001342625A true JP2001342625A (en) 2001-12-14

Family

ID=26588835

Family Applications (1)

Application Number Title Priority Date Filing Date
JP2001096908A Pending JP2001342625A (en) 2000-03-30 2001-03-29 Preboring construction method preventing elution of chromium

Country Status (1)

Country Link
JP (1) JP2001342625A (en)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2019048938A (en) * 2017-09-11 2019-03-28 太平洋セメント株式会社 Organic soil solidification method
CN112521951A (en) * 2020-11-26 2021-03-19 中节能大地（杭州）环境修复有限公司 Preparation method of composite stabilizer for treating heavy metal contaminated soil
FR3105032A1 (en) * 2019-12-23 2021-06-25 Holcim Technology Ltd PROCESS FOR TREATMENT OF SOIL POLLUTED BY SULPHATES
CN113087428A (en) * 2021-03-26 2021-07-09 唐山冀东水泥外加剂有限责任公司 Chromium reducing agent, preparation method thereof and cement

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2019048938A (en) * 2017-09-11 2019-03-28 太平洋セメント株式会社 Organic soil solidification method
FR3105032A1 (en) * 2019-12-23 2021-06-25 Holcim Technology Ltd PROCESS FOR TREATMENT OF SOIL POLLUTED BY SULPHATES
WO2021130327A1 (en) * 2019-12-23 2021-07-01 Holcim Technology Ltd Method for treating soil contaminated by sulphates
CN112521951A (en) * 2020-11-26 2021-03-19 中节能大地（杭州）环境修复有限公司 Preparation method of composite stabilizer for treating heavy metal contaminated soil
CN113087428A (en) * 2021-03-26 2021-07-09 唐山冀东水泥外加剂有限责任公司 Chromium reducing agent, preparation method thereof and cement
CN113087428B (en) * 2021-03-26 2022-06-07 唐山冀东水泥外加剂有限责任公司 Chromium reducing agent, preparation method thereof and cement

Similar Documents

Publication Publication Date Title
JP4712483B2 (en) Treatment composition and treatment method for heavy metal contaminated soil
Saeed et al. Strength of lime-cement stabilized tropical lateritic clay contaminated by heavy metals
JP2000086322A (en) Hexavalent chromium leach reducing agent for hydraulic material, and method for reducing hexavalent chromium leach
JP2003225640A (en) Solidifying and insolubilizing agent for contaminated soil
JPH06167597A (en) Composition for manufacture of barrier for prevention of diffusion of contaminant and manufacture of barrier
JP2003193462A (en) Soil solidification treatment method
JP2001342625A (en) Preboring construction method preventing elution of chromium
KR0134253B1 (en) Curing method of industrial waste and soil mixture
JP3274376B2 (en) Agglomerating agent for mud, solidifying agent using it
JP5020544B2 (en) Organic-inorganic composite type coating curing agent, mortar or concrete treatment method using the same, and hardened cement
JP4093808B2 (en) Soil solidifying agent
JP2007216069A (en) Treating method of contaminated soil
Falciglia et al. Development of a performance threshold approach for identifying the management options for stabilisation/solidification of lead polluted soils
JP3942404B2 (en) Cement admixture
JP2002060751A (en) Hexavalent chromium elution-reducing agent and cement composition by using the same
JP6750817B2 (en) Water pollution prevention method
JP3599711B2 (en) Hexavalent chromium fixative mixture and hexavalent chromium elution prevention method
JP2005162862A (en) Heavy metal elution controller and method for controlling heavy metal elution
JP5020543B2 (en) Mortar or concrete processing method and hardened cement
JP3772552B2 (en) Solidified material for heavy metal contaminated soil and method for producing the same
JP3463505B2 (en) Solidifying material for wet soil and method for improving solidification of wet soil
JP4145418B2 (en) Method for producing hexavalent chromium-containing solidified product
JPH0971777A (en) Process for neutralizing solidified soil resulting from solidification of sludge and soft soil
JPS61256952A (en) Steel material preventive concret, mortar and cement
JP3177760B2 (en) Solidified material for soft sludge waste