JP7519799B2 - Solidification aid, solidification treatment material, and soil solidification treatment method - Google Patents
Solidification aid, solidification treatment material, and soil solidification treatment method Download PDFInfo
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- 238000007711 solidification Methods 0.000 title claims description 246
- 230000008023 solidification Effects 0.000 title claims description 246
- 239000002689 soil Substances 0.000 title claims description 184
- 239000000463 material Substances 0.000 title claims description 128
- 238000000034 method Methods 0.000 title claims description 32
- 239000004568 cement Substances 0.000 claims description 72
- 239000002893 slag Substances 0.000 claims description 63
- 239000005416 organic matter Substances 0.000 claims description 55
- 239000011790 ferrous sulphate Substances 0.000 claims description 44
- 235000003891 ferrous sulphate Nutrition 0.000 claims description 44
- 229910000359 iron(II) sulfate Inorganic materials 0.000 claims description 44
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 39
- 239000000126 substance Substances 0.000 claims description 29
- 239000011400 blast furnace cement Substances 0.000 claims description 19
- 239000010440 gypsum Substances 0.000 claims description 19
- 229910052602 gypsum Inorganic materials 0.000 claims description 19
- QJZYHAIUNVAGQP-UHFFFAOYSA-N 3-nitrobicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic acid Chemical compound C1C2C=CC1C(C(=O)O)C2(C(O)=O)[N+]([O-])=O QJZYHAIUNVAGQP-UHFFFAOYSA-N 0.000 claims description 15
- 239000004021 humic acid Substances 0.000 claims description 15
- PUKLDDOGISCFCP-JSQCKWNTSA-N 21-Deoxycortisone Chemical compound C1CC2=CC(=O)CC[C@]2(C)[C@@H]2[C@@H]1[C@@H]1CC[C@@](C(=O)C)(O)[C@@]1(C)CC2=O PUKLDDOGISCFCP-JSQCKWNTSA-N 0.000 claims description 13
- FCYKAQOGGFGCMD-UHFFFAOYSA-N Fulvic acid Natural products O1C2=CC(O)=C(O)C(C(O)=O)=C2C(=O)C2=C1CC(C)(O)OC2 FCYKAQOGGFGCMD-UHFFFAOYSA-N 0.000 claims description 13
- 239000002509 fulvic acid Substances 0.000 claims description 13
- 229940095100 fulvic acid Drugs 0.000 claims description 13
- 238000002156 mixing Methods 0.000 claims description 12
- 239000003864 humus Substances 0.000 claims description 7
- BAUYGSIQEAFULO-UHFFFAOYSA-L iron(2+) sulfate (anhydrous) Chemical compound [Fe+2].[O-]S([O-])(=O)=O BAUYGSIQEAFULO-UHFFFAOYSA-L 0.000 claims 9
- SURQXAFEQWPFPV-UHFFFAOYSA-L iron(2+) sulfate heptahydrate Chemical compound O.O.O.O.O.O.O.[Fe+2].[O-]S([O-])(=O)=O SURQXAFEQWPFPV-UHFFFAOYSA-L 0.000 description 36
- 239000002245 particle Substances 0.000 description 18
- 229910001385 heavy metal Inorganic materials 0.000 description 16
- 239000000203 mixture Substances 0.000 description 16
- 239000002585 base Substances 0.000 description 15
- UHOVQNZJYSORNB-UHFFFAOYSA-N Benzene Chemical compound C1=CC=CC=C1 UHOVQNZJYSORNB-UHFFFAOYSA-N 0.000 description 12
- 229910052785 arsenic Inorganic materials 0.000 description 12
- RQNWIZPPADIBDY-UHFFFAOYSA-N arsenic atom Chemical compound [As] RQNWIZPPADIBDY-UHFFFAOYSA-N 0.000 description 12
- JOPOVCBBYLSVDA-UHFFFAOYSA-N chromium(6+) Chemical compound [Cr+6] JOPOVCBBYLSVDA-UHFFFAOYSA-N 0.000 description 12
- 238000010828 elution Methods 0.000 description 10
- 239000000843 powder Substances 0.000 description 10
- 238000012360 testing method Methods 0.000 description 9
- OSGAYBCDTDRGGQ-UHFFFAOYSA-L calcium sulfate Chemical compound [Ca+2].[O-]S([O-])(=O)=O OSGAYBCDTDRGGQ-UHFFFAOYSA-L 0.000 description 8
- 230000000052 comparative effect Effects 0.000 description 8
- 239000003513 alkali Substances 0.000 description 7
- 238000000605 extraction Methods 0.000 description 7
- 238000002386 leaching Methods 0.000 description 7
- 239000002002 slurry Substances 0.000 description 7
- 239000011398 Portland cement Substances 0.000 description 6
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 6
- 239000010426 asphalt Substances 0.000 description 6
- 230000007613 environmental effect Effects 0.000 description 6
- 238000006703 hydration reaction Methods 0.000 description 6
- 238000004519 manufacturing process Methods 0.000 description 6
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 5
- 238000006243 chemical reaction Methods 0.000 description 5
- 239000003415 peat Substances 0.000 description 5
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 4
- UCKMPCXJQFINFW-UHFFFAOYSA-N Sulphide Chemical compound [S-2] UCKMPCXJQFINFW-UHFFFAOYSA-N 0.000 description 4
- 239000007864 aqueous solution Substances 0.000 description 4
- 229910001653 ettringite Inorganic materials 0.000 description 4
- 230000006872 improvement Effects 0.000 description 4
- 150000004682 monohydrates Chemical class 0.000 description 4
- 239000002244 precipitate Substances 0.000 description 4
- 239000000047 product Substances 0.000 description 4
- 239000011593 sulfur Substances 0.000 description 4
- 229910052717 sulfur Inorganic materials 0.000 description 4
- 241000196324 Embryophyta Species 0.000 description 3
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 3
- 239000002253 acid Substances 0.000 description 3
- 230000002378 acidificating effect Effects 0.000 description 3
- DIZPMCHEQGEION-UHFFFAOYSA-H aluminium sulfate (anhydrous) Chemical compound [Al+3].[Al+3].[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O DIZPMCHEQGEION-UHFFFAOYSA-H 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 230000036571 hydration Effects 0.000 description 3
- 239000012046 mixed solvent Substances 0.000 description 3
- 238000002360 preparation method Methods 0.000 description 3
- 230000008569 process Effects 0.000 description 3
- 150000003467 sulfuric acid derivatives Chemical class 0.000 description 3
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 2
- 235000008733 Citrus aurantifolia Nutrition 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- 235000011941 Tilia x europaea Nutrition 0.000 description 2
- 230000008901 benefit Effects 0.000 description 2
- AXCZMVOFGPJBDE-UHFFFAOYSA-L calcium dihydroxide Chemical compound [OH-].[OH-].[Ca+2] AXCZMVOFGPJBDE-UHFFFAOYSA-L 0.000 description 2
- 239000000920 calcium hydroxide Substances 0.000 description 2
- 229910001861 calcium hydroxide Inorganic materials 0.000 description 2
- 239000003795 chemical substances by application Substances 0.000 description 2
- 229910052804 chromium Inorganic materials 0.000 description 2
- 239000011651 chromium Substances 0.000 description 2
- 230000001186 cumulative effect Effects 0.000 description 2
- 150000004683 dihydrates Chemical class 0.000 description 2
- 239000006185 dispersion Substances 0.000 description 2
- 238000009415 formwork Methods 0.000 description 2
- 230000002401 inhibitory effect Effects 0.000 description 2
- 239000004571 lime Substances 0.000 description 2
- 239000007791 liquid phase Substances 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 239000011259 mixed solution Substances 0.000 description 2
- 238000013031 physical testing Methods 0.000 description 2
- 238000010998 test method Methods 0.000 description 2
- 239000012085 test solution Substances 0.000 description 2
- 150000004685 tetrahydrates Chemical class 0.000 description 2
- PMZURENOXWZQFD-UHFFFAOYSA-L Sodium Sulfate Chemical compound [Na+].[Na+].[O-]S([O-])(=O)=O PMZURENOXWZQFD-UHFFFAOYSA-L 0.000 description 1
- 238000000944 Soxhlet extraction Methods 0.000 description 1
- 229910000323 aluminium silicate Inorganic materials 0.000 description 1
- 239000002956 ash Substances 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- ZOMBKNNSYQHRCA-UHFFFAOYSA-J calcium sulfate hemihydrate Chemical compound O.[Ca+2].[Ca+2].[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O ZOMBKNNSYQHRCA-UHFFFAOYSA-J 0.000 description 1
- 238000005119 centrifugation Methods 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 239000003610 charcoal Substances 0.000 description 1
- 239000004927 clay Substances 0.000 description 1
- 238000005056 compaction Methods 0.000 description 1
- 238000012669 compression test Methods 0.000 description 1
- 239000000470 constituent Substances 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- HNPSIPDUKPIQMN-UHFFFAOYSA-N dioxosilane;oxo(oxoalumanyloxy)alumane Chemical compound O=[Si]=O.O=[Al]O[Al]=O HNPSIPDUKPIQMN-UHFFFAOYSA-N 0.000 description 1
- 238000004090 dissolution Methods 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 238000011049 filling Methods 0.000 description 1
- 239000000706 filtrate Substances 0.000 description 1
- 239000010881 fly ash Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 150000004688 heptahydrates Chemical class 0.000 description 1
- 239000002663 humin Substances 0.000 description 1
- 239000010842 industrial wastewater Substances 0.000 description 1
- XBDUTCVQJHJTQZ-UHFFFAOYSA-L iron(2+) sulfate monohydrate Chemical compound O.[Fe+2].[O-]S([O-])(=O)=O XBDUTCVQJHJTQZ-UHFFFAOYSA-L 0.000 description 1
- 238000006386 neutralization reaction Methods 0.000 description 1
- 150000004686 pentahydrates Chemical class 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- OTYBMLCTZGSZBG-UHFFFAOYSA-L potassium sulfate Chemical compound [K+].[K+].[O-]S([O-])(=O)=O OTYBMLCTZGSZBG-UHFFFAOYSA-L 0.000 description 1
- 229910052939 potassium sulfate Inorganic materials 0.000 description 1
- 235000011151 potassium sulphates Nutrition 0.000 description 1
- 238000010298 pulverizing process Methods 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 230000004044 response Effects 0.000 description 1
- 239000013049 sediment Substances 0.000 description 1
- 238000007873 sieving Methods 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 229910052938 sodium sulfate Inorganic materials 0.000 description 1
- 235000011152 sodium sulphate Nutrition 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 230000006641 stabilisation Effects 0.000 description 1
- 238000011105 stabilization Methods 0.000 description 1
- 239000003381 stabilizer Substances 0.000 description 1
- 230000000638 stimulation Effects 0.000 description 1
- 230000001629 suppression Effects 0.000 description 1
- 239000000725 suspension Substances 0.000 description 1
- 238000004154 testing of material Methods 0.000 description 1
- 238000005303 weighing Methods 0.000 description 1
Classifications
-
- 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
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P40/00—Technologies relating to the processing of minerals
- Y02P40/10—Production of cement, e.g. improving or optimising the production methods; Cement grinding
Landscapes
- Consolidation Of Soil By Introduction Of Solidifying Substances Into Soil (AREA)
- Treatment Of Sludge (AREA)
- Soil Conditioners And Soil-Stabilizing Materials (AREA)
Description
本発明は、固化助材、固化処理材及び土の固化処理方法に関する。 The present invention relates to a solidification aid, a solidification treatment material, and a method for solidifying soil.
軟弱地盤に含まれる土を固化処理する方法として、セメント系固化材等の固化材を添加する方法が採用されている。特に、含水比が高い泥炭等の有機質土は、有機物としてフミン酸やフルボ酸等の腐植物質を多く含んでいるので、有機質土を固化処理する場合、腐植物質とセメントの水和反応で生成する水酸化カルシウムとが反応して、セメントの水和が阻害されてしまう。その結果、セメントによる固化性能が十分に発揮されないことがある。 One method of solidifying soil contained in soft ground is to add a cement-based solidifying agent or other solidifying agent. In particular, organic soil such as peat, which has a high water content, contains a lot of humic substances such as humic acid and fulvic acid as organic matter. When solidifying organic soil, the humic substances react with calcium hydroxide produced by the hydration reaction of cement, inhibiting the hydration of the cement. As a result, the solidification performance of the cement may not be fully realized.
このような有機質土を固化する手段として、例えばセメントと石膏との混合物に硫酸塩を添加した固化材を用いる方法（特許文献１）や、セメントと、ブレーン比表面積が８０００ｃｍ２／ｇ以上の高炉スラグ微粉末と、石膏とを含む固化材を用いる方法（特許文献２）、あるいはセメント系固化材および硫酸第一鉄を含む固化材を用いる方法（特許文献３）が開示されている。 As means for solidifying such organic soil, there have been disclosed, for example, a method using a solidification material in which sulfate is added to a mixture of cement and gypsum (Patent Document 1), a method using a solidification material containing cement, ground granulated blast furnace slag having a Blaine specific surface area of 8000 cm2 /g or more, and gypsum (Patent Document 2), and a method using a solidification material containing a cement-based solidification material and ferrous sulfate (Patent Document 3).
しかし、特許文献１～３に記載の固化材は、有機質土を固化処理対象としてその強度を改良しうるものであるが、固化処理後の強度が十分ではなく、改善の余地があった。 However, although the solidification materials described in Patent Documents 1 to 3 can improve the strength of organic soil by solidifying it, the strength after solidification is insufficient, and there is room for improvement.
したがって、本発明は、有機質土の処理において、改良土の強度を高めることができる固化助材及び固化処理材を提供することにある。 Therefore, the present invention aims to provide a solidification aid and a solidification treatment material that can increase the strength of improved soil in the treatment of organic soil.
本発明者らは、上記課題に関し鋭意検討した結果、高炉スラグ微粉末と硫酸第一鉄とを含み、且つこれらを特定の質量比で含有する固化助材、及びこの固化助材を含む固化処理材を有機質土の固化処理に用いることによって、得られた改良土に高い強度を発現できることを見出し、本発明を完成させるに至った。 As a result of intensive research into the above-mentioned problems, the inventors discovered that by using a solidification aid containing ground granulated blast furnace slag and ferrous sulfate in a specific mass ratio, and a solidification treatment material containing this solidification aid, in the solidification treatment of organic soil, the resulting improved soil can exhibit high strength, and thus completed the present invention.
すなわち本発明は、高炉スラグ微粉末と硫酸第一鉄とを含み、
前記高炉スラグ微粉末に対する前記硫酸第一鉄の質量比が０．０１～０．４９であり、
含水状態であり、且つ腐植物質の含有量が５質量％以上である有機質含有土の固化処理に用いられる、固化助材を提供するものである。
That is, the present invention includes ground granulated blast furnace slag and ferrous sulfate,
a mass ratio of the ferrous sulfate to the ground granulated blast furnace slag is 0.01 to 0.49;
The present invention provides a solidification auxiliary material that is used in the solidification treatment of organic matter-containing soil that is in a water-containing state and has a humic substance content of 5 mass % or more.
また本発明は、固化助材と、高炉スラグを含むセメント系固化材とを含み、
前記セメント系固化材１００質量部に対する前記固化助材の割合が２０～７０質量部であり、
前記固化助材は、高炉スラグ微粉末と硫酸第一鉄とを含み、前記高炉スラグ微粉末に対する前記硫酸第一鉄の質量比が０．０１～０．４９であり、
含水状態であり、且つ腐植物質の含有量が５質量％以上である有機質含有土の固化処理に用いられる、固化処理材を提供するものである。
The present invention also includes a solidification auxiliary and a cement-based solidification material containing blast furnace slag,
The ratio of the solidification auxiliary material to 100 parts by mass of the cement-based solidification material is 20 to 70 parts by mass,
the solidification aid contains ground granulated blast furnace slag and ferrous sulfate, and the mass ratio of the ferrous sulfate to the ground granulated blast furnace slag is 0.01 to 0.49;
The present invention provides a solidification treatment material that is used for solidification treatment of organic matter-containing soil that is in a water-containing state and has a humic substance content of 5 mass % or more.
更に本発明は、固化助材及びセメント系固化材を含む固化処理材と、処理対象の土とを混合する工程を有し、
前記固化処理材は、前記セメント系固化材１００質量部に対して、前記固化助材を２０～７０質量部含み、
前記固化助材は高炉スラグ微粉末と硫酸第一鉄とを含み、且つ該高炉スラグ微粉末に対する該硫酸第一鉄の質量比が０．０１～０．４９であり、
前記セメント系固化材は高炉スラグを含み、
前記土として、含水状態であり、且つ腐植物質の含有量が５質量％以上である有機質含有土を用いる、土の固化処理方法を提供するものである。
Furthermore, the present invention includes a step of mixing a solidification treatment material containing a solidification auxiliary material and a cement-based solidification material with soil to be treated,
The solidification treatment material contains 20 to 70 parts by mass of the solidification auxiliary material relative to 100 parts by mass of the cement-based solidification material,
the solidification aid contains ground granulated blast furnace slag and ferrous sulfate, and the mass ratio of the ferrous sulfate to the ground granulated blast furnace slag is 0.01 to 0.49;
The cement-based solidification material includes blast furnace slag,
The present invention provides a soil solidification method, in which organic matter-containing soil that is in a water-containing state and has a humic substance content of 5 mass % or more is used as the soil.
本発明によれば、処理対象となる有機質含有土の強度を高めることができる。 The present invention can increase the strength of the organic matter-containing soil to be treated.
以下、本発明の好適な実施形態を説明する。以下の説明において、「Ｘ～Ｙ［Ｚ］」（Ｘ及びＹは任意の数字であり、［Ｚ］は単位である。）と記載した場合、特に断らない限り「Ｘ［Ｚ］以上Ｙ［Ｚ］以下」を意味する。 The following describes a preferred embodiment of the present invention. In the following description, when it is stated that "X to Y[Z]" (X and Y are arbitrary numbers, and [Z] is a unit), it means "X[Z] or more and Y[Z] or less" unless otherwise specified.
本発明の固化助材は、高炉スラグ微粉末と硫酸第一鉄とを含む。固化助材は、有機質含有土の固化処理において、処理後の土に高い強度を発現可能にする助材である。固化助材は、セメントや石灰、石膏等といった、水の存在下で固化性能を有する固化母材とともに用いられる。 The solidification aid of the present invention contains ground granulated blast furnace slag and ferrous sulfate. The solidification aid is an aid that enables soil containing organic matter to exhibit high strength after the solidification process. The solidification aid is used together with a solidification base material that has solidification properties in the presence of water, such as cement, lime, gypsum, etc.
本発明における「有機質含有土」は、書籍「地盤材料試験の方法と解説」（社団法人地盤工学会著、２００９年１１月発行、５３～７９ページ）において、大分類にて「有機質土」の土質区分に分類されるものを指す。具体的には、本発明における有機質含有土は、有機質粘土及び有機質火山灰土等といった中分類記号〔Ｏ（オー）〕に分類される有機質土と、泥炭や黒泥等といった中分類記号〔Ｐｔ〕に分類される高有機質土とを包含する。これらの土は、有機物を含んでおり、有機質土は有機物含有量が２０質量％未満であり、高有機質土は有機物含有量が２０質量％以上である。有機物含有量は、後述する強熱減量における値とすることができる。
以下の説明では、特に断りのない限り、「有機質含有土」はこれらの土の総称として説明する。
The "organic soil" in the present invention refers to soil classified as "organic soil" in the book "Methods and Commentary on Soil Material Testing" (published November 2009 by the Geotechnical Society, pages 53-79). Specifically, the organic soil in the present invention includes organic soil classified as O (O), such as organic clay and organic volcanic ash soil, and highly organic soil classified as Pt, such as peat and black mud. These soils contain organic matter, with organic soil having an organic matter content of less than 20% by mass and highly organic soil having an organic matter content of 20% by mass or more. The organic matter content can be the value of the loss on ignition, which will be described later.
In the following explanation, unless otherwise specified, "organic matter-containing soil" will be used as a general term for these soils.
固化助材は、含水状態の有機質含有土の固化処理に好適に用いられ、含水状態の高有機質土に対する固化処理に特に好適に用いられる。含水状態とは、後述する含水比が０％超であることを指す。固化助材は、含水比が好ましくは１００％以上、より好ましくは１５０％以上であり、好ましくは１０００％以下である有機質含有土の固化処理に用いられる。含水比は、測定対象の土において、土の乾燥質量に対する土中の水の質量の比を百分率で表したものであり、例えばＪＩＳ Ａ１２０３：２００９に準じて測定することができる。
このような含水比を有する土に対して、固化助材を固化母材とともに用いることによって、水と固化母材との比を適切な割合に制御困難であることに起因して固化母材のみでは強度発現が困難であった土に対しても、高い強度を発現させることができる。
The solidification aid is preferably used for the solidification treatment of organic matter-containing soil in a water-containing state, and is particularly preferably used for the solidification treatment of highly organic soil in a water-containing state. The water-containing state refers to a state in which the water content ratio described later is greater than 0%. The solidification aid is used for the solidification treatment of organic matter-containing soil in which the water content ratio is preferably 100% or more, more preferably 150% or more, and preferably 1000% or less. The water content ratio is the ratio of the mass of water in the soil to the dry mass of the soil in the measurement target, expressed as a percentage, and can be measured, for example, in accordance with JIS A1203:2009.
By using a solidification auxiliary together with the solidification base material for soil with such a moisture content, it is possible to achieve high strength even in soil that would be difficult to achieve strength with just the solidification base material due to the difficulty of controlling the ratio of water to the solidification base material at an appropriate ratio.
本発明の固化助材の適用対象となる有機質含有土は、含水状態の該土において、腐植物質を含むものであることが好ましい。腐植物質とは、有機質含有土に含まれる有機質を構成する成分であり、例えば、フミン酸及びフルボ酸等の腐植酸性成分、ヒューミン、並びにビチューメン等の成分が挙げられる。
固化助材は、腐植物質を好ましくは５質量％以上、更に好ましくは７質量％以上であり、好ましくは２０質量％以下含む有機質含有土の固化処理に好適に用いられる。腐植物質の含有量は、含水状態の有機質含有土の質量に対する割合とする。
腐植物質をこのような割合で含む土に対して、固化助材を固化母材とともに用いることによって、固化反応が腐植物質によって阻害されにくくなるので、固化母材のみでは強度発現が困難であった土に対しても、固化反応を効率よく進行させて、固化処理後の土に高い強度を発現させることができる。
The organic matter-containing soil to which the solidification aid of the present invention is applied is preferably one that contains humic substances in a water-containing state. Humic substances are components that constitute the organic matter contained in the organic matter-containing soil, and examples of such components include humic acidic components such as humic acid and fulvic acid, humin, and bitumen.
The solidification auxiliary is preferably used for solidification treatment of organic matter-containing soil containing humic substances in an amount of preferably 5% by mass or more, more preferably 7% by mass or more, and preferably 20% by mass or less. The content of humic substances is defined as the ratio to the mass of the organic matter-containing soil in a water-containing state.
By using a solidification aid together with the solidification base material for soil containing such a proportion of humus, the solidification reaction is less likely to be inhibited by the humus, so that even in soil that would be difficult to develop strength with the solidification base material alone, the solidification reaction can be promoted efficiently, and the soil can develop high strength after solidification treatment.
特に、固化助材は、腐植物質のうちフミン酸及びフルボ酸のうち少なくとも一種を含む有機質含有土に対して用いることが好ましい。フミン酸及びフルボ酸のうち少なくとも一種を含む有機質含有土を固化処理対象とする場合、フミン酸とフルボ酸との合計量が好ましくは５質量％以上、更に好ましくは７質量％以上であり、好ましくは２０質量％以下である有機質含有土に対して、固化助材を用いることが好ましい。フミン酸及びフルボ酸の含有量は、含水状態の有機質含有土の質量に対する割合とする。
フミン酸及びフルボ酸をこのような割合で含む土に対して、固化助材を固化母材とともに用いることによって、固化母材中のアルカリと、フミン酸及びフルボ酸等の酸性成分との中和が生じにくくなり、アルカリによる固化反応が阻害されにくくなる。その結果、固化母材のみでは強度発現が困難であった土に対しても、固化反応を効率よく進行させて、固化処理後の土に高い強度を発現させることができる。
In particular, the solidification aid is preferably used for organic matter-containing soil containing at least one of humic acid and fulvic acid among humic substances. When organic matter-containing soil containing at least one of humic acid and fulvic acid is to be solidified, it is preferable to use the solidification aid for organic matter-containing soil in which the total amount of humic acid and fulvic acid is preferably 5% by mass or more, more preferably 7% by mass or more, and preferably 20% by mass or less. The content of humic acid and fulvic acid is the ratio to the mass of the organic matter-containing soil in a water-containing state.
By using a solidification auxiliary together with the solidification base material for soil containing humic acid and fulvic acid in such a ratio, neutralization of the alkali in the solidification base material with the acidic components such as humic acid and fulvic acid is unlikely to occur, and the solidification reaction by alkali is unlikely to be inhibited. As a result, even for soil that is difficult to develop strength with the solidification base material alone, the solidification reaction can be efficiently advanced, and the soil after solidification can develop high strength.
腐植物質並びにフミン酸及びフルボ酸の存在の有無及び含有量は、例えば後述する実施例に記載の方法で測定することができる。 The presence and content of humic substances, humic acid, and fulvic acid can be measured, for example, by the method described in the Examples below.
処理対象となる有機質含有土は、その強熱減量が、好ましくは２０～９０質量％、更に好ましくは２５～７０質量％である。有機質含有土の強熱減量は、例えばＪＩＳ Ａ１２２６：２００９に準じて測定することができる。このような強熱減量を有する有機質含有土に対して、固化助材を固化母材とともに用いることによって、固化処理後の土に高い強度を発現させることができる。 The ignition loss of the organic matter-containing soil to be treated is preferably 20 to 90% by mass, and more preferably 25 to 70% by mass. The ignition loss of organic matter-containing soil can be measured, for example, in accordance with JIS A1226:2009. By using a solidification aid together with the solidification base material for organic matter-containing soil with such an ignition loss, it is possible to achieve high strength in the soil after solidification treatment.
上述した腐植物質あるいは腐植酸性成分の含有量、含水比及び強熱減量のうち少なくとも一つを満たす有機質含有土としては、高有機質土が挙げられる。つまり、本発明の固化助材は、高有機質土の固化処理に特に好適に用いられる。高有機質土は、枯死した植物等が多年にわたり堆積した土である。高有機質土としては、未分解で繊維質である泥炭（前記書籍における小分類記号〔Ｐｔ〕）や、堆積物の分解が進み黒色のものである黒炭（前記書籍における小分類記号〔Ｍｋ〕）が挙げられる。高有機質土は、その採取時点において、上述した腐植物質の含有量、含水比及び強熱減量のうち少なくとも一つを満たしていることが、固化処理の際の作業効率を高める点から好ましい。 Highly organic soil is an example of an organic-content soil that satisfies at least one of the above-mentioned humus or humus acidic component content, water content, and ignition loss. In other words, the solidification aid of the present invention is particularly suitable for use in the solidification treatment of highly organic soil. Highly organic soil is soil in which dead plants and the like have accumulated over many years. Examples of highly organic soil include peat (subcategory symbol [Pt] in the above book), which is undecomposed and fibrous, and black charcoal (subcategory symbol [Mk] in the above book), which is black due to the decomposition of sediments. It is preferable that highly organic soil satisfies at least one of the above-mentioned humus content, water content, and ignition loss at the time of collection in order to increase the work efficiency during the solidification treatment.
次に、固化助材に含まれる成分について説明する。上述のとおり、本発明の固化助材は、高炉スラグ微粉末と硫酸第一鉄とを含む。 Next, the components contained in the solidification aid will be explained. As mentioned above, the solidification aid of the present invention contains ground granulated blast furnace slag and ferrous sulfate.
固化助材の性状は、高炉スラグ微粉末と硫酸第一鉄の粉末とを含む粉状物（固体）であってもよく、あるいは、高炉スラグ微粉末と硫酸第一鉄とを水等の分散媒に分散させたスラリーであってもよい。 The solidification aid may be in the form of a powder (solid) containing ground granulated blast furnace slag and powdered ferrous sulfate, or it may be a slurry in which ground granulated blast furnace slag and ferrous sulfate are dispersed in a dispersing medium such as water.
固化助材に含まれる高炉スラグ微粉末は、製鉄所等の高炉で副次的に発生するスラグを水冷し粉砕した粉状物である。高炉スラグ微粉末としては、例えば市販品の高炉水砕スラグや、ＪＩＳ Ａ６２０６：２０１３に規定されるものを用いることができる。一般的に、高炉スラグは、固化母材に含まれるアルカリ等の刺激を受けて硬化する潜在水硬性を有しており、このことに起因して、含水状態の有機質含有土を固化処理したときに、固化処理後の土の強度を向上させることができる。 The granulated blast furnace slag contained in the solidification aid is a powder made by water-cooling and pulverizing slag that is a by-product of blast furnaces in steelworks and the like. Examples of granulated blast furnace slag that can be used include commercially available granulated blast furnace slag and that specified in JIS A6206:2013. Generally, blast furnace slag has latent hydraulic properties that harden in response to the stimulation of alkalis and the like contained in the solidification base material. Due to this, when organic matter-containing soil in a hydrated state is solidified, the strength of the soil after solidification can be improved.
高炉スラグ微粉末は、そのブレーン比表面積が、好ましくは３０００～７０００ｃｍ２／ｇ、更に好ましくは３５００～６０００ｃｍ２／ｇである。高炉スラグ微粉末のブレーン比表面積は、ＪＩＳ Ｒ５２０１：２０１５「セメントの物理試験方法」に準拠して測定することができる。
このようなブレーン比表面積を有する高炉スラグ微粉末を用いることによって、固化助材の製造コスト及び固化処理に要するコストを低減しつつ、固化処理後の土に高い強度を発現させることができる。
The ground granulated blast furnace slag has a Blaine specific surface area of preferably 3000 to 7000 cm 2 /g, more preferably 3500 to 6000 cm 2 /g. The Blaine specific surface area of the ground granulated blast furnace slag can be measured in accordance with JIS R5201:2015 "Physical testing methods for cement."
By using ground granulated blast furnace slag having such a Blaine specific surface area, it is possible to reduce the manufacturing costs of the solidification auxiliary material and the costs required for the solidification treatment, while allowing the soil to exhibit high strength after the solidification treatment.
高炉スラグ微粉末は、その硫化物硫黄の含有量が、好ましくは０．５質量％以上、より好ましくは０．６質量％以上、更に好ましくは０．７５質量％以上であり、好ましくは１．５質量％以下である。硫化物硫黄の含有量は、ＪＩＳ Ｒ５２０２：２０１０「セメントの化学分析方法」に準拠して測定することができる。
高炉スラグ微粉末の硫化物硫黄の含有量がこのような範囲にあることによって、固化母材としてセメントを含む場合に、セメントに含まれる六価クロム等の重金属類を硫化物硫黄によって、三価クロムに還元して、固化処理後の土からの重金属類の溶出を環境基準以下に抑制することができる。
The ground granulated blast furnace slag has a sulfide sulfur content of preferably 0.5 mass% or more, more preferably 0.6 mass% or more, further preferably 0.75 mass% or more, and preferably 1.5 mass% or less. The sulfide sulfur content can be measured in accordance with JIS R5202:2010 "Methods for chemical analysis of cement".
Since the sulfide sulfur content of the ground granulated blast furnace slag is within this range, when cement is included as a solidification base material, heavy metals such as hexavalent chromium contained in the cement can be reduced to trivalent chromium by the sulfide sulfur, and the leaching of heavy metals from the soil after solidification can be suppressed to below environmental standards.
固化助材に含まれる硫酸第一鉄は、含水状態の有機質含有土をセメント等の固化母材とともに処理するにあたり、セメントと土中の水が接触した後に生成する水酸化カルシウムによる高アルカリによって有機質含有土中の腐植物質が多量に溶解することを抑制し、腐植物質によるセメントの水和阻害を防ぐとともに、硫酸イオンの供給によりエトリンガイトの生成量を増加させて、固化処理後の土の強度を向上させる目的で用いられる。
これに加えて、セメントに含まれる六価クロムを還元し、固化処理後の土からのクロムの溶出を環境基準以下に抑制することができるという利点もある。さらに、有機質含有土中に含有する砒素が固化処理後に溶出することを抑制することができるという利点もある。
The ferrous sulfate contained in the solidification aid is used for the purposes of preventing a large amount of humic substances in the organic matter-containing soil from being dissolved due to high alkalinity caused by calcium hydroxide that is generated when the cement comes into contact with the water in the soil, when hydrous organic matter-containing soil is treated together with a solidification base material such as cement, preventing the humic substances from inhibiting the hydration of cement, and increasing the amount of ettringite produced by supplying sulfate ions, thereby improving the strength of the soil after solidification.
In addition, it has the advantage of reducing the hexavalent chromium contained in the cement and suppressing the elution of chromium from the soil after solidification to below the environmental standard, and also has the advantage of suppressing the elution of arsenic contained in organic matter-containing soil after solidification.
硫酸第一鉄は、無水物であってもよく、１水和物、４水和物、５水和物及び７水和物等の水和物であってもよい。固化助材の製造コストを低減して汎用性の高い固化助材を得る観点から、硫酸第一鉄は水和物であることが好ましく、１水和物であることが更に好ましい。 Ferrous sulfate may be anhydrous or may be a hydrate such as the monohydrate, tetrahydrate, pentahydrate, or heptahydrate. From the viewpoint of reducing the manufacturing cost of the solidification aid and obtaining a solidification aid with high versatility, it is preferable that the ferrous sulfate be a hydrate, and more preferably the monohydrate.
硫酸第一鉄は、好ましくは粉末状である。この場合、硫酸第一鉄の粉末を構成する粒子の最大粒径は、好ましくは１０００μｍ以下、より好ましくは９００μｍ以下である。また、硫酸第一鉄の粉末を構成粒子の平均粒径は、好ましくは１０～７０μｍ、更に好ましくは１５～６５μｍである。
硫酸第一鉄がこのような粒径を有する粒子であることによって、高アルカリによる腐植物の溶解の抑制や硫酸イオンの供給が適正な速度で進行し、強度が向上するといった効果が奏される。このような粒径を有する硫酸第一鉄は、例えば市販品を用いたり、あるいは粉砕やふるい分け等を行って得ることができる。
The ferrous sulfate is preferably in a powder form. In this case, the maximum particle size of the particles constituting the ferrous sulfate powder is preferably 1000 μm or less, more preferably 900 μm or less. The average particle size of the particles constituting the ferrous sulfate powder is preferably 10 to 70 μm, and more preferably 15 to 65 μm.
When the ferrous sulfate is in the form of particles having such a particle size, it has the effect of suppressing the dissolution of humic plants by high alkali and of supplying sulfate ions at an appropriate rate, thereby improving strength. Ferrous sulfate having such a particle size can be obtained, for example, from a commercially available product or by crushing, sieving, etc.
硫酸第一鉄における最大粒径及び平均粒径は、例えば以下の方法で測定することができる。具体的には、レーザー回折式粒度分布測定装置（例えばMalvern Instruments社製マスターサイザー３０００、及び乾式分散ユニットAERO S（分散条件：空気プレッシャー４ｂａｒで試料を循環）を使用して最大粒径および平均粒径を測定できる。最大粒径は、体積累計１００容量％粒子径Ｄmaxとし、平均粒径は体積累計５０容量％粒子径Ｄ５０とすることができる。 The maximum particle size and average particle size of ferrous sulfate can be measured, for example, by the following method. Specifically, the maximum particle size and average particle size can be measured using a laser diffraction particle size distribution measuring device (e.g., Mastersizer 3000 manufactured by Malvern Instruments, and a dry dispersion unit AERO S (dispersion conditions: sample circulated at an air pressure of 4 bar). The maximum particle size can be defined as the 100% volume cumulative particle size Dmax , and the average particle size can be defined as the 50% volume cumulative particle size D50 .
本発明の固化助材は、高炉スラグ微粉末と硫酸第一鉄との含有割合が特定の範囲となっていることが好ましい。詳細には、高炉スラグ微粉末に対する硫酸第一鉄の質量比は、好ましくは０．０１～０．４９であることが好ましく、更に好ましくは０．０５～０．３５である。
高炉スラグ微粉末と硫酸第一鉄との含有割合がこのような範囲にあることによって、固化処理後の土の強度を更に向上させることができる。これに加えて、固化処理対象となる土に含まれる砒素等の重金属類や、固化助材とともに用いられるセメント等の固化母材に含まれる六価クロム等の重金属類の外部への溶出を環境基準以下となるように抑制することができる。特に、固化処理対象となる土が高有機質土である場合、高有機質土は砒素の含有量が比較的高いので、高炉スラグ微粉末と硫酸第一鉄との含有割合がこのような範囲とすることで、砒素の環境中への溶出を効果的に抑制しつつ、強度を発現させることができる点で有利である。
The solidification aid of the present invention preferably has a content ratio of ground granulated blast furnace slag and ferrous sulfate within a specific range. In detail, the mass ratio of ferrous sulfate to ground granulated blast furnace slag is preferably 0.01 to 0.49, and more preferably 0.05 to 0.35.
By setting the content ratio of the ground granulated blast furnace slag and ferrous sulfate in this range, the strength of the soil after solidification can be further improved. In addition, the elution of heavy metals such as arsenic contained in the soil to be solidified and heavy metals such as hexavalent chromium contained in the solidification base material such as cement used together with the solidification auxiliary can be suppressed to below the environmental standard. In particular, when the soil to be solidified is highly organic soil, the content of arsenic in highly organic soil is relatively high. Therefore, by setting the content ratio of the ground granulated blast furnace slag and ferrous sulfate in this range, it is advantageous in that the elution of arsenic into the environment can be effectively suppressed while the strength can be developed.
固化助材中の高炉スラグ微粉末の含有量は、好ましくは６７～９９質量％、更に好ましくは７４～９５質量％である。また、固化助材中の硫酸第一鉄の含有量は、好ましくは１～３３質量％、更に好ましくは５～２６質量％である。各含有量がこのような範囲であることによって、重金属類の環境中への溶出を抑制しつつ、強度が高い土を得ることができる。硫酸第一鉄の含有量は、１水和物換算での値とする。 The content of ground granulated blast furnace slag in the solidification aid is preferably 67-99% by mass, more preferably 74-95% by mass. The content of ferrous sulfate in the solidification aid is preferably 1-33% by mass, more preferably 5-26% by mass. By keeping the contents in these ranges, it is possible to obtain soil with high strength while suppressing the leaching of heavy metals into the environment. The content of ferrous sulfate is expressed as a value converted to monohydrate.
本発明の効果が奏される限りにおいて、固化助材は、高炉スラグ微粉末及び硫酸第一鉄に加えて、硫酸第一鉄以外の硫酸塩を更に添加してもよい。このような硫酸塩としては、水溶性硫酸塩が挙げられ、具体的には、硫酸ナトリウム、硫酸カリウム及び硫酸アルミニウム等を挙げることができる。 As long as the effects of the present invention are achieved, the solidification aid may further include sulfates other than ferrous sulfate in addition to the ground granulated blast furnace slag and ferrous sulfate. Examples of such sulfates include water-soluble sulfates, and specific examples include sodium sulfate, potassium sulfate, and aluminum sulfate.
以上の構成を有する固化助材は、セメント系固化材とともに、含水状態の有機質含有土を固化処理するための固化処理材として好適に用いることができる。つまり、本発明の固化処理材は、固化助材と、セメント系固化材とを含む。以下の説明において、固化処理材に含まれる固化助材と、固化処理対象となる有機質含有土とに関する説明は、それぞれ上述の説明が適宜適用される。 The solidification aid having the above-mentioned configuration can be suitably used as a solidification treatment material for solidifying organic matter-containing soil in a water-containing state together with a cement-based solidification material. In other words, the solidification treatment material of the present invention includes a solidification aid and a cement-based solidification material. In the following explanation, the above explanations are appropriately applied to the solidification aid contained in the solidification treatment material and the organic matter-containing soil to be solidified.
固化処理材は、セメント系固化材を含む。セメント系固化材は、固化母材としてセメントを４０質量％以上含むものである。セメント系固化材は、砂質土や粘性土等の一般的な軟弱土や、含水比が高い泥状物や有機質含有土を固化処理する幅広い用途で適用可能である。上述した固化助材を含む本発明の固化処理材は、土の強度を更に向上させることができるので、含水状態の有機質含有土、特に、含水状態の高有機質土の強度改善に好適に用いられる。これに加えて、固化処理材に含まれるセメントに由来する六価クロムや、固化処理対象の有機質含有土に含まれる砒素等の重金属類の環境中への溶出を効果的に抑制できる。 The solidification treatment material includes a cement-based solidification material. The cement-based solidification material contains 40% or more by mass of cement as a solidification base material. The cement-based solidification material can be used in a wide range of applications, such as solidification treatment of general soft soils such as sandy soils and clayey soils, and muddy soils and organic matter-containing soils with high water content. The solidification treatment material of the present invention, which contains the above-mentioned solidification auxiliary, can further improve the strength of the soil, and is therefore suitable for use in improving the strength of organic matter-containing soils in a water-containing state, particularly highly organic soils in a water-containing state. In addition, it can effectively suppress the leaching into the environment of heavy metals such as hexavalent chromium derived from the cement contained in the solidification treatment material and arsenic contained in the organic matter-containing soil to be solidified.
セメント系固化材としては、例えば高炉スラグを含むセメント系固化材が挙げられる。具体的には、セメント系固化材は、ポルトランドセメントと高炉スラグとを含む混合物若しくは高炉セメント、又はこれらに加えて、石膏や石灰、フライアッシュ及びシリカ等の一種以上の他の成分を更に含む混合物が挙げられる。つまり、セメント系固化材は、セメントと高炉スラグとを少なくとも含んでおり、ポルトランドセメント、高炉スラグ及び他の成分を含む混合物であってもよく、高炉セメント及び他の成分を含む混合物であってもよい。セメント系固化材に含まれる高炉スラグは、好ましくは高炉水砕スラグである。 An example of the cement-based solidification material is a cement-based solidification material containing blast furnace slag. Specifically, the cement-based solidification material may be a mixture containing Portland cement and blast furnace slag, or blast furnace cement, or a mixture containing one or more other components such as gypsum, lime, fly ash, and silica in addition to the above. In other words, the cement-based solidification material contains at least cement and blast furnace slag, and may be a mixture containing Portland cement, blast furnace slag, and other components, or a mixture containing blast furnace cement and other components. The blast furnace slag contained in the cement-based solidification material is preferably granulated blast furnace slag.
セメント系固化材の構成成分として、好ましくは３０～９５質量％のポルトランドセメントと好ましくは５～７０質量％の高炉スラグとを含む混合物を用いる場合、セメント系固化材は、該混合物１００質量部に対して、他の成分を好ましくは５～４３質量部含む。 When a mixture containing preferably 30 to 95% by mass of Portland cement and preferably 5 to 70% by mass of blast furnace slag is used as the constituent components of the cement-based solidification material, the cement-based solidification material preferably contains 5 to 43 parts by mass of other components per 100 parts by mass of the mixture.
ポルトランドセメントとしては、例えばＪＩＳ Ｒ５２１０：２０１９に規定されるものを用いることができる。
高炉セメントとしては、ポルトランドセメントと高炉スラグとを含むものであり、例えばＪＩＳ Ｒ５２１１：２０１９に規定されるものを用いることができる。具体的には、高炉セメントは、高炉スラグを５質量％超３０質量％以下含む高炉セメントＡ種、高炉スラグを３０質量％超６０質量％以下含む高炉セメントＢ種及び高炉スラグを６０質量％超７０質量％以下含む高炉セメントＣ種のうち少なくとも一種を用いることができる。
As the Portland cement, for example, one specified in JIS R5210:2019 can be used.
The blast furnace cement contains Portland cement and blast furnace slag, and can be, for example, one specified in JIS R5211: 2019. Specifically, the blast furnace cement can be at least one of blast furnace cement type A containing more than 5% by mass and not more than 30% by mass of blast furnace slag, blast furnace cement type B containing more than 30% by mass and not more than 60% by mass of blast furnace slag, and blast furnace cement type C containing more than 60% by mass and not more than 70% by mass of blast furnace slag.
石膏としては、例えば無水石膏、半水石膏及び二水石膏のうち少なくとも一種を用いることができる。有機質含有土の強度改善を効率的に行う観点から、石膏は、無水石膏および二水石膏のうち少なくとも一種を用いることが好ましく、無水石膏を用いることが更に好ましい。 As the gypsum, for example, at least one of anhydrous gypsum, hemihydrate gypsum, and dihydrate gypsum can be used. From the viewpoint of efficiently improving the strength of organic matter-containing soil, it is preferable to use at least one of anhydrous gypsum and dihydrate gypsum, and it is even more preferable to use anhydrous gypsum.
セメント系固化材は、高炉セメント及び石膏を含むことが好ましく、高炉セメントＢ種及び石膏を含むことがより好ましく、高炉セメントＢ種及び無水石膏を含むことが更に好ましく、セメントとして高炉セメントＢ種のみを用い且つ石膏として無水石膏のみを用いることが一層好ましい。
また、固化処理材中に高炉セメント及び石膏を含む場合、高炉セメントの含有量が好ましくは７０～９５質量％であり、且つ石膏の含有量が好ましくは５～３０質量％である。石膏の含有量は無水石膏換算での値とする。
セメント系固化材中に高炉セメントＢ種を用いることによって、セメント単体のみでは強度発現が困難な含水状態の有機質含有土を処理対象とした場合であっても、高炉セメント中の高炉スラグの潜在水硬性を固化助材中の高炉スラグ微粉末とともに十分に発現させて、セメントのアルカリ水和反応による土の固化性能を更に効率よく発現させることができる。これに加えて、石膏を用いることによって、セメントの水和によって生成するエトリンガイトを処理対象となる土に効率的に生成させることができるので、土の固化性能を一層効果的に向上させることができる。また、固化性能のさらなる向上に伴って、砒素や六価クロム等の重金属類の環境中への溶出をより一層低減することができる。
The cement-based solidification material preferably contains blast furnace cement and gypsum, more preferably contains blast furnace cement type B and gypsum, even more preferably contains blast furnace cement type B and anhydrous gypsum, and even more preferably uses only blast furnace cement type B as the cement and only anhydrous gypsum as the gypsum.
In addition, when the solidification treatment material contains blast furnace cement and gypsum, the content of the blast furnace cement is preferably 70 to 95 mass %, and the content of the gypsum is preferably 5 to 30 mass %. The content of the gypsum is expressed as an anhydrous gypsum equivalent value.
By using blast furnace cement type B in the cement-based solidification material, even when the soil to be treated is organic matter-containing soil in a water-containing state that is difficult to develop strength with cement alone, the latent hydraulic properties of the blast furnace slag in the blast furnace cement can be fully developed together with the fine powder of blast furnace slag in the solidification auxiliary material, and the soil solidification performance due to the alkali hydration reaction of the cement can be more efficiently developed. In addition, by using gypsum, ettringite, which is generated by the hydration of cement, can be efficiently generated in the soil to be treated, so that the soil solidification performance can be more effectively improved. In addition, with the further improvement in the solidification performance, the leaching of heavy metals such as arsenic and hexavalent chromium into the environment can be further reduced.
固化処理材を製造する方法は、例えば、固化助材とセメント系固化材とを混合することによって得ることができる。具体的には、例えば、固化助材、高炉セメント及び石膏を混合したり、固化助材、ポルトランドセメント、高炉スラグ及び石膏を混合したりして得ることができる。製造時及び運搬時の利便性の向上と、固化処理を行う現場において固化処理対象の土の性状に応じて固化処理材の使用量を調整しやすくする観点から、固化助材の粉末と、セメント系固化材の粉末とを混合した態様であることが好ましい。このように得られた固化処理材は、好ましくは粉末状である。 The solidification treatment material can be produced, for example, by mixing a solidification aid with a cement-based solidification material. Specifically, for example, the solidification treatment material can be obtained by mixing a solidification aid, blast furnace cement, and gypsum, or by mixing a solidification aid, Portland cement, blast furnace slag, and gypsum. From the viewpoint of improving convenience during production and transportation, and making it easier to adjust the amount of solidification treatment material used according to the properties of the soil to be solidified at the site where the solidification treatment is performed, it is preferable that the solidification treatment material is in the form of a mixture of powder of the solidification aid and powder of the cement-based solidification material. The solidification treatment material obtained in this way is preferably in powder form.
固化処理材において、固化助材とセメント系固化材との含有割合は、セメント系固化材１００質量部に対して、固化助材を好ましくは２０～７０質量部、更に好ましくは３０～６０質量部含む。このような割合で各材料を含むことによって、含水状態の有機質含有土に対する強度発現を更に向上させることができるとともに、六価クロムや砒素等の重金属類の環境中への溶出を効果的に抑制できる。 In the solidification treatment material, the content ratio of the solidification aid and the cement-based solidification material is preferably 20 to 70 parts by mass, and more preferably 30 to 60 parts by mass, of the solidification aid per 100 parts by mass of the cement-based solidification material. By including each material in such a ratio, it is possible to further improve the strength exhibited by the organic matter-containing soil in a water-containing state, and to effectively suppress the leaching of heavy metals such as hexavalent chromium and arsenic into the environment.
高炉スラグによる潜在水硬性とセメントによるアルカリ水和反応とをバランスよく発現させて、含水土の固化性能をより一層高める観点から、固化処理材中の高炉スラグ及び高炉スラグ微粉末の合計量は、好ましくは３５～６５質量％、更に好ましくは４０～６０質量％である。 From the viewpoint of achieving a good balance between the latent hydraulic properties of the blast furnace slag and the alkaline hydration reaction of the cement, and further improving the solidification performance of the wet soil, the total amount of blast furnace slag and ground granulated blast furnace slag in the solidification treatment material is preferably 35 to 65% by mass, and more preferably 40 to 60% by mass.
以上の構成を有する固化処理材を用いて、処理対象である含水状態の有機質含有土を固化処理する方法を以下に説明する。以下の説明において、固化処理材と、固化処理対象となる有機質含有土とに関する説明は、それぞれ上述の説明が適宜適用される。 The method of solidifying the organic matter-containing soil in a wet state, which is the target of the solidification treatment, using the solidification treatment material having the above-mentioned configuration is described below. In the following explanation, the above explanations regarding the solidification treatment material and the organic matter-containing soil to be solidified are applied as appropriate.
本発明の土の固化処理方法は、固化処理材と、処理対象の土とを混合する工程を有する。処理対象の土としては、含水状態の有機質含有土、特に、含水状態の高有機質土を用いることができる。 The soil solidification method of the present invention includes a step of mixing a solidification treatment material with the soil to be treated. The soil to be treated can be soil containing organic matter in a moist state, particularly highly organic soil in a moist state.
本方法における混合方法は、固化処理材及び処理対象の土のうち一方を他方に添加して混合してもよく、固化処理材と処理対象の土とを同時に混合してもよい。また混合する固化処理材は、粉状のものを用いてもよく、水等の分散媒に分散させたスラリーを用いてもよい。 In this method, the mixing method may involve adding one of the solidification treatment material and the soil to be treated to the other, or the solidification treatment material and the soil to be treated may be mixed simultaneously. The solidification treatment material to be mixed may be in powder form, or a slurry dispersed in a dispersing medium such as water may be used.
固化処理材の混合量は、処理対象の土の種類や性状によって適宜変更可能であるが、処理対象の土１ｍ３に対して、好ましくは１００～５００ｋｇ、より好ましくは２００～４５０ｋｇ、更に好ましくは３００～４００ｋｇである。このような範囲で混合することによって、処理コストを抑制しながらも、土中にエトリンガイトを効率よく生成させることができ、固化処理後の土の強度を高いものとすることができる。また、強度の向上に伴って、砒素や六価クロム等の重金属類の環境中への溶出をより一層低減することができる。処理対象の土の体積は、含水状態での値とする。 The amount of solidification treatment material mixed can be changed as appropriate depending on the type and properties of the soil to be treated, but is preferably 100 to 500 kg, more preferably 200 to 450 kg, and even more preferably 300 to 400 kg per 1 m3 of soil to be treated. By mixing in such a range, ettringite can be efficiently generated in the soil while suppressing the treatment cost, and the strength of the soil after solidification can be increased. In addition, with the improvement in strength, the elution of heavy metals such as arsenic and hexavalent chromium into the environment can be further reduced. The volume of the soil to be treated is the value in a wet state.
固化処理材と処理対象の土との混合は、例えばバックホウ、ミキシングバケット装着バックホウ、スタビライザー、自走式土質改良機、定置式ミキサー、ホバート型ミキサー、トレンチャー型攪拌混合機、深層混合処理機、パワーブレンダー、プラント混合等の本技術分野において通常用いられる混合装置又は方法を用いることができる。 The solidification treatment material can be mixed with the soil to be treated using mixing equipment or methods commonly used in this technical field, such as a backhoe, a backhoe equipped with a mixing bucket, a stabilizer, a self-propelled soil improvement machine, a stationary mixer, a Hobart mixer, a trencher type agitator mixer, a deep layer mixer, a power blender, or a plant mixer.
以上の構成を有する固化助材、及びこれを含む固化処理材は、水を含み且つ有機質を多く含む土を処理対象とした場合でも、固化反応が有機質等に阻害されることなく進行し、固化処理後の土の強度を十分に発現させることができる。これに加えて、固化処理後の土からの重金属類の溶出を環境基準以下に抑制することができる。
一般的に、処理対象の土として、含水状態の有機質含有土、特に含水状態の高有機質土を用いてセメント系固化材による固化処理を行う場合、水／セメント比を適切な比率となるようにして所望の強度を発現させるために、通常の粘性土や砂質土を処理する場合と比較して、セメント系固化材の添加量を多くする必要がある。一方で、セメント系固化材の添加量を多くしてしまうと、これに伴ってセメントの含有量も多くなってしまうので、セメント系固化材中のセメントに含まれる六価クロム等の重金属類が固化処理後の土に持ち込まれやすくなる。また、高有機質土等の有機質含有土は、砒素の含有量が多いことが知られている。したがって、高有機質土等の含水状態の有機質含有土を固化処理対象とする場合には、重金属類が固化処理後の土に多く含まれてしまうので、固化処理後の土からの重金属類の溶出を制御する必要がある。
この点に関して、セメント系固化材に加えて固化助材を含む固化処理材を用いて高有機質土等の有機質含有土を固化処理することによって、セメント系固化材単体で使用した場合と比較して、セメント系固化材の使用量を多くしなくとも、エトリンガイトの形成による高い強度を土に発現させることができる。また、含水状態の有機質含有土における含水比を加熱などによって調整する工程を別途行わなくても、処理対象となる土そのものに固化処理材を混合させて、処理効率を高めつつ、所望の高い強度を発現させることができる。これに加えて、固化処理後の土からの重金属類の溶出を環境基準以下に効率よく制御することができる。更に、セメントの使用量も少なくなるので、固化処理後の土への六価クロムの持ち込み量を少なくすることができ、重金属類の溶出抑制に寄与する。
The solidification auxiliary material having the above-mentioned configuration and the solidification treatment material containing the same are capable of proceeding with the solidification reaction without being inhibited by the organic matter, etc., even when the soil to be treated contains water and a large amount of organic matter, and can ensure that the soil has sufficient strength after the solidification treatment. In addition, the elution of heavy metals from the soil after the solidification treatment can be suppressed to below the environmental standard.
In general, when the soil to be treated is a water-containing organic matter-containing soil, particularly a water-containing highly organic matter-containing soil, and is solidified with a cement-based solidification material, it is necessary to add a larger amount of cement-based solidification material than when treating normal clayey soil or sandy soil in order to achieve a proper water/cement ratio and develop the desired strength. On the other hand, if the amount of cement-based solidification material added is increased, the cement content also increases, so that heavy metals such as hexavalent chromium contained in the cement in the cement-based solidification material are easily carried into the soil after the solidification treatment. In addition, it is known that organic matter-containing soil such as highly organic soil has a high arsenic content. Therefore, when water-containing organic matter-containing soil such as highly organic soil is to be solidified, the heavy metals are contained in a large amount in the soil after the solidification treatment, so it is necessary to control the elution of heavy metals from the soil after the solidification treatment.
In this regard, by using a solidification treatment material containing a solidification auxiliary in addition to a cement-based solidification material to solidify organic-containing soil such as high organic soil, it is possible to make the soil develop high strength due to the formation of ettringite without increasing the amount of cement-based solidification material used, compared to the case of using only a cement-based solidification material. In addition, even without a separate process of adjusting the water content of the organic-containing soil in a water-containing state by heating or the like, the soil to be treated can be mixed with the solidification treatment material itself to develop the desired high strength while increasing the treatment efficiency. In addition, the elution of heavy metals from the soil after solidification can be efficiently controlled to below the environmental standard. Furthermore, since the amount of cement used is reduced, the amount of hexavalent chromium carried into the soil after solidification can be reduced, which contributes to suppressing the elution of heavy metals.
以下、実施例により本発明を更に詳細に説明する。本発明の範囲は、かかる実施例に制限されない。 The present invention will be described in more detail below with reference to examples. The scope of the present invention is not limited to these examples.
〔製造例〕
＜固化助材及びセメント系固化材の作製＞
高炉スラグ微粉末（国産）、硫酸第一鉄（１水和物；中国産）及び硫酸アルミニウム（１４水和物；大明化学工業（株）製、工業品）を以下の表１に示す割合で混合して、異なる組成を有する１０種類の粉状の固化助材（表１中、「固化助材１～８」として示す。）を得た。
また、高炉セメントＢ種（宇部三菱セメント（株）製）と、石膏（無水石膏；タイ産）とを以下の表１に示す割合で混合して、異なる組成を有する２種類の粉状のセメント系固化材（表２中、「固化材ａ～ｂ」として示す。）を得た。
[Production Example]
<Preparation of solidification aid and cement-based solidification material>
Ground granulated blast furnace slag (domestic), ferrous sulfate (monohydrate; Chinese), and aluminum sulfate (tetrahydrate; Taimei Chemical Industry Co., Ltd., industrial product) were mixed in the ratios shown in Table 1 below to obtain ten types of powdered solidification aids having different compositions (shown as "solidification aids 1 to 8" in Table 1).
In addition, blast furnace cement type B (manufactured by Ube Mitsubishi Cement Co., Ltd.) and gypsum (anhydrous gypsum; produced in Thailand) were mixed in the ratios shown in Table 1 below to obtain two types of powdered cement-based solidification materials having different compositions (shown as "solidification materials a to b" in Table 2).
固化助材及びセメント系固化材の作製に用いた各材料の化学組成を、以下の表３に示す。
高炉セメントＢ種の化学組成は、ＪＩＳ Ｒ ５２０２：２０１０「セメントの化学分析方法」に準拠して測定した。
無水石膏の化学組成は、ＪＩＳ Ｒ９１０１：２０１８「せっこうの化学分析方法」準拠して測定した。
高炉スラグ微粉末および硫酸第一鉄１水和物の化学組成は、ＪＩＳ Ｍ８８５３：１９９８「セラミックス用アルミノけい酸塩質原料の化学分析方法」に準拠して測定した。
各材料のブレーン比表面積は、ＪＩＳ Ｒ５２０１：２０１５「セメントの物理試験方法」に準拠して測定した。
The chemical compositions of the materials used in preparing the solidification auxiliary material and the cement-based solidification material are shown in Table 3 below.
The chemical composition of blast-furnace cement type B was measured in accordance with JIS R 5202:2010 "Methods for chemical analysis of cement."
The chemical composition of the anhydrous gypsum was measured in accordance with JIS R9101:2018 "Method for chemical analysis of gypsum."
The chemical compositions of the ground granulated blast furnace slag and ferrous sulfate monohydrate were measured in accordance with JIS M8853:1998 "Method of chemical analysis of aluminosilicate raw materials for ceramics."
The Blaine specific surface area of each material was measured in accordance with JIS R5201:2015 "Physical testing methods for cement."
〔実施例１～８及び比較例１～８〕
＜１．試料土＞
固化処理対象となる土として、北海道で採取した泥炭Ａ、Ｂ、Ｃを試料土として使用した。試料土の各物性は以下の表４に示すとおりであった。これらの試料土は、いずれも含水状態の高有機質土であり、有機物を２０質量％以上含むものである。
[Examples 1 to 8 and Comparative Examples 1 to 8]
<1. Sample soil>
The sample soils to be solidified were peat A, B, and C collected in Hokkaido. The physical properties of the sample soils are shown in Table 4. All of these sample soils are highly organic soils in a wet state, containing 20% or more by mass of organic matter.
試料土の含水比は、ＪＩＳ Ａ１２０３：２００９「土の含水比試験方法」に準拠して測定した。
試料土の湿潤密度は、直径５ｃｍ、高さ１０ｃｍの型枠に試料土を充填し、充填された試料の質量（ｇ）から、型枠の容積（ｃｍ３）を除して求めた。
試料土のｐＨは、ＪＧＳ ０２１１－２００９「土懸濁液のｐＨ試験方法」に準拠して測定した。
試料土の強熱減量は、ＪＩＳ Ａ１２２６：２００９「土の強熱減量試験方法」に準拠して測定した。
The moisture content of the sample soil was measured in accordance with JIS A1203:2009 "Testing method for moisture content of soil."
The wet density of the sample soil was determined by filling a formwork 5 cm in diameter and 10 cm in height with the sample soil and subtracting the volume of the formwork (cm 3 ) from the mass (g) of the filled sample.
The pH of the sample soil was measured in accordance with JGS 0211-2009 "pH test method for soil suspensions."
The ignition loss of the sample soil was measured in accordance with JIS A1226:2009 "Test method for ignition loss of soil."
試料土の腐植物質の含有量は、熊登繁幸・島谷登著、「土質安定処理効果に及ぼす有機物の影響と耐有機性固化材について」、土木試験書月報 Ｎｏ．４０２、１９８６年１１月、ｐｐ．１５－２６の図－４を引用し、以下に示す手順に沿って測定した。
フミン酸は、ベンゼンとアルコールの混合溶媒に不溶、アルカリに可溶且つ酸に不溶の腐植物質である。フルボ酸は、ベンゼンとアルコールの混合溶媒に不溶、酸及びアルカリに可溶な腐植物質である。ビチューメンは、ベンゼンとアルコールの混合溶媒に可溶で酸及びアルカリに不溶の腐植物質である。
まず、測定対象となる含水状態の試料土をホバート型ミキサーで撹拌して、含水状態における質量を測定した後、該試料土を２ｍｍの標準網篩で裏ごしして室内にて自然乾燥させて、抽出用試料とした。抽出用試料の含水比をＪＩＳ Ａ１２０３：２００９にて測定し、土粒子の質量を算出した。
次いで、抽出用試料の一定量（１０ｇ）を円筒ろ紙に入れ、湯せん器上のソックスレー抽出装置中でエタノールとベンゼンの混合液（質量比１：１）によって、ビチューメンを抽出した。この抽出は、抽出器中の溶媒が無色になるまで継続して行った。抽出終了後、受器中の抽出液を５０℃で恒温乾燥し、その乾燥物を秤量し、ビチューメン量とした。
続いて、ビチューメンを抽出した後の抽出用試料を風乾し、該試料を０．５ＮのＮａＯＨ水溶液中に４８時間浸し、その後、０．５ＮのＨＣｌ水溶液を加え、混合液とした。そして、この混合液を遠心分離し、ろ液と沈殿物とに分離した。得られた沈殿物に対し、０．５ＮのＮａＯＨ水溶液と０．５ＮのＨＣｌ水溶液とを用いる上述の工程を繰り返して行った後、再度得られた沈殿物に対して純水による洗浄を行って、フミン酸を含む液相を得た。この液相を９０℃の炉で乾燥し、その乾燥物を秤量し、フミン酸量とした。
アルカリ不溶成分は、前述の遠心分離で得られた沈殿物を別途に恒温乾燥後、秤量した。
また、試料土の強熱減量測定値を試料土の有機物含有量とし、この有機物含有量から、ビチューメン、フミン酸及びアルカリ不溶成分（土粒子質量を除く）の各成分量を減じた値をフルボ酸量とした。含水状態の試料土に対する腐植物質の含有質量割合を、以下の表４に示す。
The humus content of the sample soil was measured according to the following procedure, citing Figure 4 in "The Influence of Organic Matter on the Soil Stabilization Effect and Organic-Resistant Solidification Materials" by Shigeyuki Kumato and Noboru Shimatani, Civil Engineering Test Book Monthly Report No. 402, November 1986, pp. 15-26.
Humic acid is a humic substance that is insoluble in a mixed solvent of benzene and alcohol, soluble in alkali, and insoluble in acid. Fulvic acid is a humic substance that is insoluble in a mixed solvent of benzene and alcohol, soluble in acid and alkali. Bitumen is a humic substance that is soluble in a mixed solvent of benzene and alcohol, and insoluble in acid and alkali.
First, the wet sample soil to be measured was stirred in a Hobart mixer, and the mass of the wet sample soil was measured. The sample soil was then sieved through a 2 mm standard mesh sieve and naturally dried indoors to prepare an extraction sample. The moisture content of the extraction sample was measured according to JIS A1203:2009, and the mass of the soil particles was calculated.
Next, a certain amount (10 g) of the sample for extraction was placed in a cylindrical filter paper, and the bitumen was extracted with a mixture of ethanol and benzene (mass ratio 1:1) in a Soxhlet extraction apparatus on a hot water bath. This extraction was continued until the solvent in the extractor became colorless. After the extraction was completed, the extract in the receiver was dried at a constant temperature of 50°C, and the dried product was weighed to obtain the amount of bitumen.
Next, the sample for extraction after bitumen extraction was air-dried, and the sample was immersed in a 0.5N NaOH aqueous solution for 48 hours, after which a 0.5N HCl aqueous solution was added to obtain a mixed solution. This mixed solution was then centrifuged to separate a filtrate and a precipitate. The above-mentioned process using a 0.5N NaOH aqueous solution and a 0.5N HCl aqueous solution was repeated for the obtained precipitate, and the obtained precipitate was washed again with pure water to obtain a liquid phase containing humic acid. This liquid phase was dried in an oven at 90°C, and the dried product was weighed to obtain the amount of humic acid.
The alkali-insoluble component was determined by separately drying the precipitate obtained by the above-mentioned centrifugation at a constant temperature and then weighing it.
The measured ignition loss of the sample soil was used as the organic matter content of the sample soil, and the amount of fulvic acid was calculated by subtracting the amounts of bitumen, humic acid, and alkali-insoluble components (excluding the soil particle mass) from the organic matter content. The mass ratio of humic substances to the sample soil in a wet state is shown in Table 4 below.
＜２．固化処理材及びこれを用いた固化処理土の作製＞
上述の製造例で作成した固化助材とセメント系固化材とを、以下の表５～表８に示す割合で混合して、粉状の固化処理材を調製した。
次いで、粉状の固化処理材を試料土１ｍ３当たり４００ｋｇの割合で、各試料土に添加し、ホバート型ミキサーを用いて９０秒間混合した。混合後、掻き落としを行い、さらに９０秒間混合して、以下の表５～表８に示す組成を有する実施例１～８及び比較例１～８の固化処理後の土（以下、これを固化処理土ともいう。）を作製した。
<2. Preparation of solidification treatment material and solidification-treated soil using the same>
The solidification auxiliary materials prepared in the above-mentioned manufacturing examples and the cement-based solidification materials were mixed in the ratios shown in Tables 5 to 8 below to prepare powdered solidification treatment materials.
Next, 400 kg of powdered solidification treatment material was added to each sample soil per 1 m3 of sample soil, and mixed for 90 seconds using a Hobart mixer. After mixing, the soil was scraped off and further mixed for 90 seconds to produce the solidification-treated soils of Examples 1 to 8 and Comparative Examples 1 to 8 (hereinafter also referred to as solidification-treated soils) having the compositions shown in Tables 5 to 8 below.
＜３．固化処理土の強度測定＞
実施例及び比較例の固化処理土につき、以下の方法で強度を測定した。
まず、実施例及び比較例の固化処理土をそれぞれ、ＪＧＳ ０８２１「安定処理土の締固めをしない供試体作成方法」に準拠して成型し、直径５ｃｍ、高さ１０ｃｍの円柱供試体を得た。これらの供試体を温度２０℃、湿度９０％ＲＨで密封した状態で７日間及び２８日間養生した。
次いで、養生後の各供試体につき、一軸圧縮強さ（ｋＮ／ｍ２）を、ＪＩＳ Ａ１２１６「土の一軸圧縮試験方法」に準拠して測定した。一軸圧縮強さの値が高いほど、固化処理土の強度が高いことを示す。結果を以下の表５～表８に示す。
<3. Strength measurement of solidified treated soil>
The strength of the solidified treated soils of the Examples and Comparative Examples was measured by the following method.
First, the solidified treated soils of the examples and comparative examples were molded in accordance with JGS 0821 "Test specimen preparation method for stabilized treated soil without compaction" to obtain cylindrical specimens with a diameter of 5 cm and a height of 10 cm. These specimens were cured for 7 and 28 days in a sealed state at a temperature of 20°C and a humidity of 90% RH.
Next, the unconfined compressive strength (kN/ m2 ) of each test specimen after curing was measured in accordance with JIS A1216 "Unconfined compression test method for soil". The higher the unconfined compressive strength value, the higher the strength of the solidification treated soil. The results are shown in Tables 5 to 8 below.
＜４．重金属類の溶出試験＞
実施例２～６及び比較例３～７の固化処理土につき、上述の方法で28日間養生した各供試体を用いて、環境庁告示第４６号に準拠して検液を作製した。その検液の六価クロム濃度および砒素濃度をＪＩＳ Ｋ０１０２「工場排水試験方法」に準拠してそれぞれ測定した。結果を表６及び表７に示す。
<4. Heavy metal elution test>
For the solidified treated soils of Examples 2 to 6 and Comparative Examples 3 to 7, test solutions were prepared in accordance with Environment Agency Notification No. 46 using each test specimen that had been cured for 28 days using the above-mentioned method. The hexavalent chromium and arsenic concentrations of the test solutions were measured in accordance with JIS K0102 "Testing Method for Industrial Wastewater." The results are shown in Tables 6 and 7.
＜５．固化処理材の流動性試験＞
上述の製造例で作成した固化助材とセメント系固化材とを、以下の表５に示す割合で混合して、粉状の固化処理材を調製した。その後、固化処理材と水とを１：１の質量割合にてミキサーで１分間混合し、固化処理材のスラリーを調製した。
これを所定時間３５℃温度条件で静置したあと、回転粘度計（Ｈａａｋｅ社製、Ｒｏｔｏｖｉｓｃｏ ＲＶ－１）を用いて、３５℃におけるスラリーの見掛け粘度を経時的に測定した。
本試験では、３５℃におけるスラリーの見掛け粘度が１２５ｍＰａ・ｓとなったときの経過時間をスラリーの可使時間とし、可使時間１８０分以上であったものを、取り扱い性が良好である（表５中、記号「○」で示す。）とし、可使時間１８０分未満のものを取り扱い性が不良である（表５中、記号「×」で示す。）とした。結果を以下の表５に示す。
<5. Fluidity test of solidification treatment material>
A powdered solidification treatment material was prepared by mixing the solidification auxiliary material and the cement-based solidification material prepared in the above-mentioned manufacturing example in the ratio shown in the following Table 5. Then, the solidification treatment material and water were mixed in a mixer in a mass ratio of 1:1 for 1 minute to prepare a slurry of the solidification treatment material.
After leaving this to stand at a temperature condition of 35° C. for a predetermined time, the apparent viscosity of the slurry at 35° C. was measured over time using a rotational viscometer (Rotovisco RV-1, manufactured by Haake Corporation).
In this test, the time elapsed until the apparent viscosity of the slurry at 35°C reached 125 mPa·s was defined as the pot life of the slurry, and those with a pot life of 180 minutes or more were deemed to have good handleability (indicated by the symbol "O" in Table 5), and those with a pot life of less than 180 minutes were deemed to have poor handleability (indicated by the symbol "X" in Table 5). The results are shown in Table 5 below.
表５～表８の結果に示すように、高炉スラグ微粉末及び硫酸第一鉄をそれぞれ所定量含む固化助材を用いた固化処理材（実施例１～８）は、高炉スラグ微粉末及び硫酸第一鉄をそれぞれ所定量含まないもの（比較例１～８）と比較して、いずれの泥炭を処理対象とした場合でも、一軸圧縮強さが高くなっており、固化処理後の強度を改善できることが判る。
また、表６及び表７に示すように、実施例２～６の固化処理材は、比較例３～７の固化処理材と比較して、固化処理土からの六価クロム溶出量及び砒素溶出量をともに環境基準値（六価クロム：０．０５ｍｇ／Ｌ、砒素：０．０１ｍｇ／Ｌ）以下に抑制でき、またその溶出抑制度合が高いことも判る。
更に、硫酸第一鉄を含む固化助材（実施例１）と、硫酸第一鉄に代えて、硫酸アルミニウムを用いた固化助材（比較例２）とを比較すると、実施例１の固化助材は、スラリーとしての取り扱い性が良好となった。したがって、強度の向上と取り扱い性の向上とを両立する点で、硫酸第一鉄を所定量含む固化助材を用いることが有利であることが判る。
As shown by the results in Tables 5 to 8, the solidification treatment materials (Examples 1 to 8) using solidification aids containing a predetermined amount of ground granulated blast furnace slag and ferrous sulfate showed higher uniaxial compressive strength than those (Comparative Examples 1 to 8) that did not contain a predetermined amount of ground granulated blast furnace slag and ferrous sulfate, regardless of the type of peat treated, and it was found that the strength after solidification treatment could be improved.
Furthermore, as shown in Tables 6 and 7, the solidification treatment materials of Examples 2 to 6 can suppress the amount of hexavalent chromium and arsenic leaching from the solidified treated soil to below the environmental standard values (hexavalent chromium: 0.05 mg/L, arsenic: 0.01 mg/L) compared to the solidification treatment materials of Comparative Examples 3 to 7, and it can also be seen that the degree of leaching suppression is high.
Furthermore, when comparing the solidification aid containing ferrous sulfate (Example 1) with the solidification aid using aluminum sulfate instead of ferrous sulfate (Comparative Example 2), the solidification aid of Example 1 had good handleability as a slurry. Therefore, it is found that it is advantageous to use a solidification aid containing a predetermined amount of ferrous sulfate in terms of achieving both improved strength and improved handleability.
Claims (11)
前記高炉スラグ微粉末に対する前記硫酸第一鉄の質量比が０．０３～０．４９であり、
含水状態であり、且つ腐植物質の含有量が５質量％以上である有機質含有土の固化処理に用いられる、固化助材。 Contains ground granulated blast furnace slag and ferrous sulfate,
a mass ratio of the ferrous sulfate to the ground granulated blast furnace slag is 0.03 to 0.49;
A solidification aid used in the solidification treatment of organic matter-containing soil that is in a moist state and has a humus content of 5% by mass or more.
前記フミン酸と前記フルボ酸との合計量の割合が５質量％以上である前記有機質含有土の固化処理に用いられる、請求項１に記載の固化助材。 The humic substance includes at least one of humic acid and fulvic acid,
The solidification aid according to claim 1, which is used in the solidification treatment of the organic matter-containing soil in which the total amount of the humic acid and the fulvic acid is 5 mass% or more.
前記セメント系固化材１００質量部に対する前記固化助材の割合が２０～７０質量部であり、
前記固化助材は、高炉スラグ微粉末と硫酸第一鉄とを含み、前記高炉スラグ微粉末に対する前記硫酸第一鉄の質量比が０．０３～０．４９であり、
含水状態であり、且つ腐植物質の含有量が５質量％以上である有機質含有土の固化処理に用いられる、固化処理材。 A solidification aid and a cement-based solidification material containing blast furnace slag,
The ratio of the solidification auxiliary material to 100 parts by mass of the cement-based solidification material is 20 to 70 parts by mass,
the solidification aid contains ground granulated blast furnace slag and ferrous sulfate, and the mass ratio of the ferrous sulfate to the ground granulated blast furnace slag is 0.03 to 0.49;
A solidification treatment material used for solidification treatment of organic matter-containing soil that is in a moist state and has a humic substance content of 5% by mass or more.
前記固化処理材は、前記セメント系固化材１００質量部に対して、前記固化助材を２０～７０質量部含み、
前記固化助材は高炉スラグ微粉末と硫酸第一鉄とを含み、且つ該高炉スラグ微粉末に対する該硫酸第一鉄の質量比が０．０３～０．４９であり、
前記セメント系固化材は高炉スラグを含み、
前記土として、含水状態であり、且つ腐植物質の含有量が５質量％以上である有機質含有土を用いる、土の固化処理方法。 The method includes a step of mixing a solidification treatment material containing a solidification auxiliary material and a cement-based solidification material with soil to be treated,
The solidification treatment material contains 20 to 70 parts by mass of the solidification auxiliary material relative to 100 parts by mass of the cement-based solidification material,
the solidification auxiliary material contains ground granulated blast furnace slag and ferrous sulfate, and the mass ratio of the ferrous sulfate to the ground granulated blast furnace slag is 0.03 to 0.49;
The cement-based solidification material includes blast furnace slag,
The soil solidification treatment method uses, as the soil, organic matter-containing soil that is in a water-containing state and has a humic substance content of 5 mass% or more.
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