JP2021183662A - Soil modification material, soil modification method, modified soil, and soil modification treatment method - Google Patents
Soil modification material, soil modification method, modified soil, and soil modification treatment method Download PDFInfo
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- 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
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- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
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Abstract
Description
本発明は、土壌改質材、土壌改質方法、改質土壌、及び、土壌改質処理工法に関する。 The present invention relates to a soil reforming material, a soil reforming method, a modified soil, and a soil reforming treatment method.
近年、環境負荷を低減する観点、最終処分場の許容量の観点等から、建設工事、土木工事の現場等で発生する土壌を、最終処分場で埋め立てることなく、再利用することが望まれている。しかし、発生する土壌の性状によっては、そのままの状態で再利用することができない場合がある。
このような場合、土壌と土壌改質材とを混合して改質土壌を形成し、該改質土壌を種々用途で利用する検討が行われている（特許文献１参照）。
土壌改質材としては、セメント系材料、生石灰、半水石膏、又は、これらを組み合わせたもの等が利用されている。
In recent years, from the viewpoint of reducing the environmental load and the capacity of the final disposal site, it is desired to reuse the soil generated at the construction site, civil engineering site, etc. without burying it at the final disposal site. There is. However, depending on the nature of the generated soil, it may not be possible to reuse it as it is.
In such a case, studies have been conducted on mixing soil and a soil modifier to form a modified soil and using the modified soil for various purposes (see Patent Document 1).
As the soil modifier, a cement-based material, quicklime, hemihydrate gypsum, or a combination thereof or the like is used.
しかしながら、上記のような土壌改質材を用いて形成された改質土壌は、運搬や転圧によって練り返されると、発現する強度が、練り返されなかった場合よりも低下することが知られている。 However, it is known that the modified soil formed by using the soil modifier as described above has a lower strength when it is kneaded by transportation or rolling than when it is not kneaded. ing.
そこで、本発明は、材齢が経過した後で練り返されても、発現する強度が低下するのを抑制することができる土壌改質材、土壌改質方法、改質土壌、又は、土壌改質処理工法を提供することを課題とする。 Therefore, the present invention relates to a soil reforming material, a soil reforming method, a modified soil, or a soil modification that can suppress a decrease in the developed strength even if the material is kneaded after the age of the material. The subject is to provide a quality treatment method.
本発明に係る土壌改質材は、土壌と混合されて改質土壌を形成する土壌改質材であって、二水石膏と、アルミナセメントと、吸水剤とを含んでおり、二水石膏１００質量部に対し、アルミナセメントを５．３質量部以上４２．９質量部以下、吸水剤を１．２質量部以上、含む。 The soil modifier according to the present invention is a soil modifier that is mixed with soil to form a modified soil, and contains dihydrate gypsum, alumina cement, and a water absorbent, and dihydrate gypsum 100. It contains 5.3 parts by mass or more and 42.9 parts by mass or less of alumina cement and 1.2 parts by mass or more of a water absorbent with respect to parts by mass.
斯かる構成によれば、改質土壌を形成して材齢が経過した後で、改質土壌を練り返しても、改質土壌が発現する強度が低下するのを抑制することができる。 According to such a configuration, even if the modified soil is kneaded again after the modified soil is formed and the age has passed, it is possible to suppress the decrease in the strength of the modified soil.
本発明に係る土壌改質材は、吸水剤を２．１質量部以上、含むことが好ましい。 The soil modifier according to the present invention preferably contains 2.1 parts by mass or more of a water absorbing agent.
斯かる構成によれば、改質土壌を形成して材齢が経過した後で、改質土壌を練り返しても、発現する強度が比較的高い改質土壌を形成することができる。 According to such a configuration, even if the modified soil is kneaded after the modified soil is formed and the age has passed, the modified soil having a relatively high strength can be formed.
吸水剤は、アニオン型ポリアクリルアミド系高分子材料、カチオン型ポリアクリルアミド系高分子材料、及び、ノニオン型ポリアクリルアミド系高分子材料からなる群から選択される少なくとも一つである、ことが好ましい。 The water absorbing agent is preferably at least one selected from the group consisting of an anionic polyacrylamide polymer material, a cationic polyacrylamide polymer material, and a nonionic polyacrylamide polymer material.
斯かる構成によれば、改質土壌を形成して材齢が経過した後で、改質土壌を練り返しても、改質土壌が発現する強度が低下するのをより効果的に抑制することができる。 According to such a configuration, even if the modified soil is kneaded again after the modified soil is formed and the age has passed, it is possible to more effectively suppress the decrease in the strength of the modified soil. Can be done.
本発明に係る土壌改質方法は、土壌と、二水石膏と、アルミナセメントと、吸水剤とを混合して改質土壌を形成する土壌改質方法であって、二水石膏１００質量部に対し、アルミナセメントを５．３質量部以上４２．９質量部以下、吸水剤を１．２質量部以上で混合し、二水石膏と、アルミナセメントと、吸水剤との合計量１００質量部に対し、土壌を１４００質量部以上２００００質量部以下で混合する。 The soil reforming method according to the present invention is a soil reforming method in which soil, dihydrate gypsum, alumina cement, and a water absorbing agent are mixed to form a reformed soil, and the amount of dihydrate gypsum is 100 parts by mass. On the other hand, the alumina cement was mixed in an amount of 5.3 parts by mass or more and 42.9 parts by mass or less, and the water absorbing agent was mixed in an amount of 1.2 parts by mass or more to make a total amount of 100 parts by mass of the dihydrate gypsum, the alumina cement and the water absorbing agent. On the other hand, the soil is mixed in an amount of 1400 parts by mass or more and 20000 parts by mass or less.
本発明に係る改質土壌は、土壌と、二水石膏と、アルミナセメントと、吸水剤とを含む改質土壌であって、二水石膏１００質量部に対し、アルミナセメントを５．３質量部以上４２．９質量部以下、吸水剤を１．２質量部以上、含んでおり、二水石膏と、アルミナセメントと、吸水剤との合計量１００質量部に対し、土壌を１４００質量部以上２００００質量部以下、含む。 The modified soil according to the present invention is a modified soil containing soil, dihydrate gypsum, alumina cement, and a water absorbent, and 5.3 parts by mass of alumina cement with respect to 100 parts by mass of dihydrate gypsum. 42.9 parts by mass or less, 1.2 parts by mass or more of water absorbent, and 1400 parts by mass or more of soil for 100 parts by mass of the total amount of dihydrate gypsum, alumina cement, and water absorbent. Including parts by mass or less.
本発明に係る土壌改質処理工法は、上記の改質土壌を地盤中で硬化させて硬化体を形成することで地盤の改質を行う。 In the soil reforming treatment method according to the present invention, the above-mentioned reformed soil is hardened in the ground to form a hardened body, thereby reforming the ground.
本発明によれば、材齢が経過した改質土壌が練り返されても、該改質土壌の発現する強度が低下するのを抑制することができる。 According to the present invention, even if the modified soil whose age has passed is kneaded, it is possible to suppress the decrease in the strength developed by the modified soil.
以下、本発明の実施形態について、説明するが、本発明は、以下の実施形態に限定されるものではない。 Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to the following embodiments.
本実施形態に係る土壌改質材は、土壌と混合されて改質土壌を形成するものである。また、土壌改質材は、二水石膏と、アルミナセメントと、吸水剤とを含む。 The soil reforming material according to the present embodiment is mixed with soil to form modified soil. Further, the soil modifier includes dihydrate gypsum, alumina cement, and a water absorbent.
二水石膏としては、天然のもの、化学合成されたもの、他の物質の副生成物として得られるもの等であってもよく、二水石膏を含む廃棄物を粉砕し、且つ、熱処理していないもの（所謂、再生二水石膏）等であってもよい。
また、二水石膏としては、ブレーン比表面積が５００ｃｍ２／ｇ以上６０００ｃｍ２／ｇ以下、好ましくは１０００ｃｍ２／ｇ以上３０００ｃｍ２／ｇ以下であるものを用いることができる。
また、土壌改質材全体の質量に対する二水石膏の質量の割合としては、特に限定されるものではなく、例えば、６９．３質量％以上９４．１質量％以下であってもよく、３５．０質量％以上４７．５質量％以下であってもよい。
The dihydrate gypsum may be natural, chemically synthesized, obtained as a by-product of other substances, etc., and the waste containing the dihydrate gypsum is crushed and heat-treated. It may be something that does not exist (so-called regenerated dihydrate gypsum) or the like.
Further, the two as the gypsum, Blaine specific surface area of 500 cm 2 / g or more 6000 cm 2 / g or less, can be preferably used not more than 1000 cm 2 / g or more 3000 cm 2 / g.
The ratio of the mass of dihydrate gypsum to the total mass of the soil modifier is not particularly limited, and may be, for example, 69.3% by mass or more and 94.1% by mass or less. It may be 0% by mass or more and 47.5% by mass or less.
アルミナセメントは、主要成分としてＣａＯ・Ａｌ２Ｏ３、ＣａＯ・２Ａｌ２Ｏ３、１２ＣａＯ・７Ａｌ２Ｏ３などのアルミン酸カルシウムを含む。また、アルミナセメントは、Ａｌ２Ｏ３を含む鉱物として、Ｃ３Ａ，Ｃ１２Ａ７，ＣＡ，ＣＡ２，Ｃ４ＡＦ等を含む。先述の「Ａ」はＡｌ２Ｏ３を表し、「Ｃ」はＣａＯを表し、「Ｆ」はＦｅ２Ｏ３を表す。
また、アルミナセメントとしては、ブレーン比表面積が２０００ｃｍ２／ｇ以上６０００ｃｍ２／ｇ以下であるものを用いることができる。具体的には、アルミナセメントとしては、ＪＩＳ Ｒ ２５２１−１９９５に規定された「耐火物用アルミナセメントの物理試験方法」に記載されたものを用いることができる。
また、アルミナセメントの含有量は、二水石膏１００質量部に対し、５．３質量部以上４２．９質量部以下あり、好ましくは１１．１質量部以上１７．６質量部以下である。
また、土壌改質材全体の質量に対するアルミナセメントの質量の割合としては、特に限定されるものではなく、例えば、５．０質量％以上２９．７質量％以下であってもよく、２．５質量％以上１５．０質量％以下であってもよい。
Alumina cement contains calcium aluminate such as CaO · Al 2 O 3, CaO · 2Al 2 O 3, 12CaO · 7Al 2 O 3 as the main component. Further, the alumina cement contains C 3 A, C 12 A 7 , CA, CA 2 , C 4 AF and the like as minerals containing Al 2 O 3. The above-mentioned "A" represents Al 2 O 3 , "C" represents Ca O, and "F" represents Fe 2 O 3 .
As the alumina cement, it can be used Blaine specific surface area is less than 2000 cm 2 / g or more 6000 cm 2 / g. Specifically, as the alumina cement, those described in "Physical test method for alumina cement for refractories" specified in JIS R 2521-1995 can be used.
The content of alumina cement is 5.3 parts by mass or more and 42.9 parts by mass or less, preferably 11.1 parts by mass or more and 17.6 parts by mass or less with respect to 100 parts by mass of dihydrate gypsum.
The ratio of the mass of alumina cement to the mass of the entire soil modifier is not particularly limited, and may be, for example, 5.0% by mass or more and 29.7% by mass or less, 2.5. It may be mass% or more and 15.0 mass% or less.
吸水剤としては、水との接触によって水を取り込み、比較的粘度の高い液体を形成する有機高分子材料を用いることができる。具体的には、吸水剤は、水と混合した際の全量（混合液の全量）に対して０．２５質量％の濃度となるように水と混合した際に、該混合液の粘度が３００ｍＰａ・ｓ以上となるものを用いることができる。
混合液の粘度は、下記の実施例に記載の方法で測定することができる。
また、吸水剤としては、アニオン型、カチオン型、又は、ノニオン型の有機高分子材料を用いることができる。具体的には、吸水剤としては、上記何れかの型のポリアクリルアミド系高分子材料、ポリアクリル酸エステル系高分子材料、ポリアクリル酸塩系高分子材料、ポリメタクリル酸エステル系高分子材料、ポリメタクリル酸塩系高分子材料、ポリアミジン塩酸塩系高分子材料、ポリビニルアルコール系高分子材料、ポリオキシエチレン系高分子材料、アクリルアミド−メタクリル酸エステル共重合体材料、及び、アクリルアミド−アクリル酸塩共重合体系高分子材料等からなる群から選択される少なくとも１つが挙げられる。好ましくは、吸水剤としては、解離基として、カルボキシル基（―ＣＯＯ−）又はスルホ基（―ＳＯ３ −）を有するアニオン型ポリアクリルアミド系高分子材料、解離基として、アンモニウム基（―ＮＨ３ ＋）又はトリメチルアンモニウム基（―Ｎ＋（ＣＨ３）３）を有するカチオン型ポリアクリルアミド系高分子材料、及び、ノニオン型ポリアクリルアミド系高分子材料からなる群から選択される少なくとも一つを用いることができる。
また、吸水剤の重量平均分子量としては、３００万以上２０００万以下のものを用いることができる。吸水剤としてアニオン型、又は、ノニオン型の有機高分子材料を用いる場合、該吸水剤の重量平均分子量としては、１５００万以上２０００万以下であってもよい。また、吸水剤としてカチオン型の有機高分子材料を用いる場合、該吸水剤の重量平均分子量としては、３００万以上１０００万以下であってもよい。重量平均分子量が上記の範囲であることで、材齢が経過した改質土壌が練り返されても、該改質土壌の発現する強度が低下するのをより効果的に抑制することができる。
また、吸水剤の含有量は、二水石膏１００質量部に対し、１．２質量部以上であり、好ましくは２．１質量部以上であり、より好ましくは３．３質量部以上５．９質量部以下である。
As the water-absorbing agent, an organic polymer material that takes in water by contact with water and forms a liquid having a relatively high viscosity can be used. Specifically, when the water absorbent is mixed with water so as to have a concentration of 0.25% by mass with respect to the total amount (total amount of the mixed solution) when mixed with water, the viscosity of the mixed solution is 300 mPa. -A substance having s or more can be used.
The viscosity of the mixture can be measured by the method described in the examples below.
Further, as the water absorbing agent, an anion type, a cationic type, or a nonionic type organic polymer material can be used. Specifically, as the water absorbent, any of the above types of polyacrylamide-based polymer material, polyacrylic acid ester-based polymer material, polyacrylic acid salt-based polymer material, polymethacrylate-based polymer material, etc. Polymethacrylate-based polymer material, polyamidine hydrochloride-based polymer material, polyvinyl alcohol-based polymer material, polyoxyethylene-based polymer material, acrylamide-methacrylate copolymer material, and acrylamide-acrylic acid salt Polymerization system At least one selected from the group consisting of polymer materials and the like can be mentioned. Preferably, the water-absorbing agent, as dissociative group, a carboxyl group (-COO -) or a sulfo group (-SO 3 -) anionic polyacrylamide polymer material having, as a dissociative group, an ammonium group (-NH 3 + ) Or at least one selected from the group consisting of a cationic polyacrylamide-based polymer material having a trimethylammonium group (-N + (CH 3 ) 3) and a nonionic polyacrylamide-based polymer material. can.
Further, as the weight average molecular weight of the water absorbing agent, those having a weight average molecular weight of 3 million or more and 20 million or less can be used. When an anion-type or nonionic-type organic polymer material is used as the water-absorbing agent, the weight average molecular weight of the water-absorbing agent may be 15 million or more and 20 million or less. When a cationic organic polymer material is used as the water absorbing agent, the weight average molecular weight of the water absorbing agent may be 3 million or more and 10 million or less. When the weight average molecular weight is in the above range, it is possible to more effectively suppress the decrease in the developed strength of the modified soil even if the modified soil after the age is kneaded.
The content of the water-absorbing agent is 1.2 parts by mass or more, preferably 2.1 parts by mass or more, and more preferably 3.3 parts by mass or more and 5.9 parts by mass with respect to 100 parts by mass of dihydrate gypsum. It is less than the mass part.
上記のように構成される土壌改質材と混合される土壌としては、特に限定されるものではなく、例えば、含水比が２０質量％以上３０質量％以下であるものが挙げられる。土壌の含水比は、「土壌中の水の質量／土壌中の固形分の質量」を「質量％」で表したものであり、地盤工学会のＪＧＳ ０１２１−２００９「土の含水比試験方法」により測定することができる。
また、上記の土壌としては、特に限定されるものではなく、例えば、コーン指数が１００ｋＮ／ｍ２以上３００ｋＮ／ｍ２以下であるものが挙げられる。コーン指数は、後述の実施例と同じ方法で測定することができる。
The soil mixed with the soil modifier configured as described above is not particularly limited, and examples thereof include those having a water content of 20% by mass or more and 30% by mass or less. The water content ratio of soil is expressed by "mass%" of "mass of water in soil / mass of solid content in soil", and JGS 0121-2009 "Test method of water content of soil" of the Japanese Geotechnical Society. Can be measured by.
The soil is not particularly limited, and examples thereof include soils having a cone index of 100 kN / m 2 or more and 300 kN / m 2 or less. The cone index can be measured by the same method as in the examples described later.
上記のように構成される土壌改質材を用いた土壌改質方法では、該土壌改質材と土壌とを混合して改質土壌を形成する。具体的には、二水石膏と、アルミナセメントと、吸水剤との合計量１００質量部に対し、土壌を１４００質量部以上２００００質量部以下、好ましくは２８００質量部以上８０００質量部以下混合する。
なお、土壌改質材を構成する各成分は、同時に、土壌と混合されてもよく、各成分が別々に土壌と混合されてもよい。
また、土壌改質材と土壌とを混合する際には、土壌の含水比に応じて、追加で水を混合してもよく、追加で水を混合しなくてもよい。
土壌の含水比としては、特に限定されるものではなく、好ましくは１０％以上、５０％以下、より好ましくは１５％以上、３５％以下である。
また、改質土壌のコーン指数としては、特に限定されるものではなく、例えば、３９０ｋＮ／ｍ２以上であってもよく、４００ｋＮ／ｍ２以上であってもよく、１０００ｋＮ／ｍ２以上であってもよい。コーン指数は、後述の実施例と同じ方法で測定することができる。
また、改質土壌のｐＨとしては、特に限定されるものではなく、例えば、１０未満であってもよく、５．８以上８．６以下であってもよい。ｐＨは、後述の実施例と同じ方法で測定することができる。
そして、上記のように形成される改質土壌を地盤中で硬化させて硬化体を形成することで地盤の改質を行うことができる（土壌改質処理工法）。
In the soil reforming method using the soil modifier configured as described above, the soil modifier and the soil are mixed to form a modified soil. Specifically, soil is mixed in an amount of 1400 parts by mass or more and 20000 parts by mass or less, preferably 2800 parts by mass or more and 8000 parts by mass or less, with respect to 100 parts by mass of the total amount of dihydrate gypsum, alumina cement and a water absorbing agent.
Each component constituting the soil modifier may be mixed with the soil at the same time, or each component may be mixed with the soil separately.
Further, when the soil modifier and the soil are mixed, additional water may be mixed or no additional water may be mixed depending on the water content ratio of the soil.
The water content of the soil is not particularly limited, and is preferably 10% or more and 50% or less, more preferably 15% or more and 35% or less.
As the cone index of reforming soil, is not particularly limited, for example, it may also be 390kN / m 2 or more, may also be 400 kN / m 2 or more, a in 1000 kN / m 2 or more May be. The cone index can be measured by the same method as in the examples described later.
The pH of the modified soil is not particularly limited, and may be, for example, less than 10 or 5.8 or more and 8.6 or less. The pH can be measured by the same method as in the examples described below.
Then, the ground can be reformed by hardening the modified soil formed as described above in the ground to form a hardened body (soil reforming treatment method).
以上のように、本実施形態に係る土壌改質材、土壌改質方法、改質土壌、及び、土壌改質処理工法は、材齢が経過した改質土壌が練り返されても、該改質土壌の発現する強度が低下するのを抑制することができる。 As described above, the soil reforming material, the soil reforming method, the reformed soil, and the soil reforming treatment method according to the present embodiment are modified even if the modified soil whose age has passed is kneaded. It is possible to suppress a decrease in the developed strength of quality soil.
即ち、土壌と混合されて改質土壌を形成する土壌改質材であって、二水石膏と、アルミナセメントと、吸水剤とを含んでおり、二水石膏１００質量部に対し、アルミナセメントを５．３質量部以上４２．９質量部以下、吸水剤を１．２質量部以上、含むことで、改質土壌を形成して材齢が経過した後で、改質土壌を練り返しても、改質土壌が発現する強度が低下するのを抑制することができる。 That is, it is a soil modifier that is mixed with soil to form a modified soil, and contains dihydrate gypsum, alumina cement, and a water absorbent, and alumina cement is added to 100 parts by mass of dihydrate gypsum. By containing 5.3 parts by mass or more and 42.9 parts by mass or less and 1.2 parts by mass or more of a water absorbent, even if the modified soil is kneaded after the age of the modified soil is formed. , It is possible to suppress the decrease in the strength of the modified soil.
また、吸水剤を２．１質量部以上、含むことで、改質土壌を形成して材齢が経過した後で、改質土壌を練り返しても、発現する強度が比較的高い改質土壌を形成することができる。 In addition, by containing 2.1 parts by mass or more of the water-absorbing agent, the modified soil has a relatively high strength even if the modified soil is kneaded after the age of the modified soil is formed. Can be formed.
また、吸水剤は、アニオン型ポリアクリルアミド系高分子材料、カチオン型ポリアクリルアミド系高分子材料、及び、ノニオン型ポリアクリルアミド系高分子材料からなる群から選択される少なくとも一つであることで、改質土壌を形成して材齢が経過した後で、改質土壌を練り返しても、改質土壌が発現する強度が低下するのをより効果的に抑制することができる。 Further, the water absorbing agent is at least one selected from the group consisting of an anionic polyacrylamide polymer material, a cationic polyacrylamide polymer material, and a nonionic polyacrylamide polymer material. Even if the modified soil is kneaded again after the quality soil is formed and the age has passed, it is possible to more effectively suppress the decrease in the strength of the modified soil.
なお、本発明に係る土壌改質材、土壌改質方法、改質土壌、及び、土壌改質処理工法は、上記実施形態に限定されるものではなく、本発明の要旨を逸脱しない範囲で種々の変更が可能である。また、上記した複数の実施形態の構成や方法等を任意に採用して組み合わせてもよく（１つの実施形態に係る構成や方法等を他の実施形態に係る構成や方法等に適用してもよく）、さらに、下記する各種の変更例に係る構成や方法等を任意に選択して、上記した実施形態に係る構成や方法等に採用してもよいことは勿論である。 The soil reforming material, the soil reforming method, the reformed soil, and the soil reforming treatment method according to the present invention are not limited to the above embodiments, and are various as long as they do not deviate from the gist of the present invention. Can be changed. Further, the configurations and methods of the plurality of embodiments described above may be arbitrarily adopted and combined (the configuration and method of one embodiment may be applied to the configurations and methods of another embodiment). Of course, it is also possible to arbitrarily select the configurations and methods according to the various modified examples described below and adopt them in the configurations and methods according to the above-described embodiment.
以下、実施例を用いて本発明を更に具体的に説明するが、本発明は、以下の実施例に限定されるものではない。 Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples.
＜土壌＞
粉末粘土（関東化成社製、品名：トチクレー）１００質量部に対して７号珪砂（瓢屋社製）を２３３質量部混合し、含水比が２５％となるように加水し、コーン指数２００ｋＮ／ｍ２となる土壌を作製した。
<Soil>
233 parts by mass of No. 7 silica sand (manufactured by Goya) was mixed with 100 parts by mass of powdered clay (manufactured by Kanto Kasei Co., Ltd., product name: Tochi clay), and water was added so that the water content ratio was 25%, and the corn index was 200 kN / A soil of m 2 was prepared.
＜土壌改質材＞
１．使用材料
・再生二水石膏（中央環境開発社製）
・試薬二水石膏（関東化学社製）
・アルミナセメント
・吸水剤１：アニオン型のポリアクリルアミド系高分子材料（粘度：７００ｍＰａ・ｓ、解離基：カルボキシル基（−ＣＯＯ−））
・吸水剤２：カチオン型のポリアクリルアミド系高分子材料（粘度：４４０ｍＰａ・ｓ、解離基：トリメチルアンモニウム基（−Ｎ＋（ＣＨ３）３））
・吸水剤３：ノニオン型のポリアクリルアミド系高分子材料（粘度：３５５ｍＰａ・ｓ）
・硫酸アルミニウム（関東化学社製）
<Soil modifier>
1. 1. Materials used ・ Recycled dihydrate gypsum (manufactured by Chuo Environmental Development Co., Ltd.)
・ Reagent Nisui gypsum (manufactured by Kanto Chemical Co., Inc.)
Alumina cement water-absorbing agent 1: anionic polyacrylamide polymer material (viscosity: 700 mPa · s, dissociative group: the carboxyl group (-COO -))
-Water absorbent 2: Cationic polyacrylamide polymer material (viscosity: 440 mPa · s, dissociation group: trimethylammonium group (-N + (CH 3 ) 3 ))
-Water absorbent 3: Nonionic polyacrylamide polymer material (viscosity: 355 mPa · s)
・ Aluminum sulfate (manufactured by Kanto Chemical Co., Inc.)
上記の粘度は、吸水剤と水とを混合した混合液の全量に対して吸水剤が０．２５質量％となる混合液の粘度であり、ＪＩＳ Ｋ ７１１７−１：１９９９「プラスチック−液状、乳濁状又は分散状の樹脂−ブルックフィールド型回転粘度計による見掛け粘度の測定方法」に基づき、Ｂ型回転粘度計（製品名：Ｂ型粘度計 ＢＬ２、東機産業社製）によって測定することができる。 The above viscosity is the viscosity of the mixed solution in which the water absorbing agent is 0.25% by mass with respect to the total amount of the mixed solution of the water absorbing agent and water. Turbid or dispersed resin-Measurement with a B-type rotational viscometer (product name: B-type viscometer BL2, manufactured by Toki Sangyo Co., Ltd.) based on "Measurement method of apparent viscosity with Brookfield type rotational viscometer" can.
上記の粘度の測定では、水４９８．７５ｇを計量した１０００ｍＬビーカー内に、吸水剤１．２５ｇを投入し、プロペラミキサにて１０００ｒｐｍで１時間撹拌して混合液を得た。 In the above viscosity measurement, 1.25 g of the water absorbing agent was put into a 1000 mL beaker weighing 498.75 g of water, and the mixture was stirred with a propeller mixer at 1000 rpm for 1 hour to obtain a mixed solution.
また、上記の粘度の測定では、上記のように作製した混合液を５００ｍＬビーカーに移して上記の粘度計に設置し、回転ローター（２号ローター）を混合液に浸し、回転数を１分あたり３０回転として測定した。測定では、読み値を記録し、２回測定の平均値を換算表に従い粘度（ｍＰ・ｓ）を算出した。 In the measurement of the above viscosity, the mixed solution prepared as described above is transferred to a 500 mL beaker, placed in the above viscometer, the rotating rotor (No. 2 rotor) is immersed in the mixed solution, and the number of rotations is per minute. It was measured as 30 rotations. In the measurement, the reading value was recorded, and the viscosity (mP · s) was calculated by using the average value of the two measurements according to the conversion table.
２．土壌改質材の配合
各実施例及び各比較例の土壌改質材の配合は、下記表１〜４の通りとした。
2. 2. Formulation of soil modifier The composition of the soil modifier in each example and each comparative example is as shown in Tables 1 to 4 below.
＜練り返し低下率＞
１．コーン指数（直後成型）
上記の土壌に対して土壌改質材を５０ｋｇ／ｍ３添加して混合し、改質土壌を作製した。そして、作製直後の改質土壌を、ＪＩＳ Ａ １２１０：２００９「突固めによる土の締固め試験方法」に基づいて、φ１０×１２．７ｃｍの鋼製型枠に打設し、２０℃で７日間養生し、供試体を得た。つまり、斯かる供試体は、材齢が経過した後で改質土壌を型枠に打設したものではない（換言すれば、改質土壌を練り返すことなく作製したものである）。
得られた供試体（改質土壌の材齢は７日）について、ＪＩＳ Ａ １２２８：２００９「締固めた土のコーン指数試験方法」に基づいて、コーン貫入試験を行い、コーン指数を得た。コーン指数（直後成型）については、下記表１〜４に示す。
<Rate of reduction in kneading>
1. 1. Cone index (immediately after molding)
The soil amendment material mixed 50 kg / m 3 was added to the above soil, to produce a modified soil. Then, the modified soil immediately after preparation is placed in a steel formwork of φ10 × 12.7 cm based on JIS A 1210: 2009 “Soil compaction test method by compaction”, and the soil is placed at 20 ° C. for 7 days. It was cured and a specimen was obtained. In other words, such specimens were not made by placing modified soil in a mold after the age of the material (in other words, they were prepared without kneading the modified soil).
The obtained specimen (the age of the modified soil was 7 days) was subjected to a cone penetration test based on JIS A 1228: 2009 "Cone index test method for compacted soil" to obtain a cone index. The cone index (immediately after molding) is shown in Tables 1 to 4 below.
２．コーン指数（材齢時成型）
密封養生した材齢７日の改質土壌を型枠に打設したこと以外は、上記の「１．コーン指数（直後成型）」と同じ条件で供試体を作製した。つまり、斯かる供試体は、材齢が経過した改質土壌が練り返されて型枠に打設されたものである。
そして、作製直後の供試体について、上記の「１．コーン指数（直後成型）」と同じ条件でコーン貫入試験を行い、コーン指数を得た。コーン指数（材齢時成型）については、下記表１〜４に示す。
2. 2. Cone index (molded at age)
Specimens were prepared under the same conditions as the above "1. Cone index (immediately after molding)" except that the modified soil of 7 days old, which had been sealed and cured, was placed in the mold. That is, in such a specimen, the modified soil whose age has passed is kneaded and placed in a formwork.
Then, the specimen immediately after production was subjected to a cone penetration test under the same conditions as in the above "1. Cone index (immediately after molding)" to obtain a cone index. The cone index (molding at age) is shown in Tables 1 to 4 below.
３．練り返し低下率
直後成型のコーン指数に対する材齢時成型のコーン指数の低下率を下記の式に基づいて算出し、「練り返し低下率」とした。練り返し低下率は、下記表１〜４に示す。
「練り返し低下率（％）」＝
｛１−（「材齢時成型のコーン指数」／「直後成型のコーン指数」）｝×１００
3. 3. Decrease rate of kneading The rate of decrease of the cone index of molding at the age of the material with respect to the cone index of immediately after kneading was calculated based on the following formula and used as the "reduction rate of kneading". The rate of decrease in kneading is shown in Tables 1 to 4 below.
"Rate of reduction in kneading (%)" =
{1- (“Cone index molded at age” / “Cone index molded immediately after”)} × 100
＜ｐＨ＞
ＪＧＳ ０２１１−２００９「土懸濁液のｐＨ試験方法」に基づいて、密封養生した材齢７日の改質土壌１８．８ｇに蒸留水７１．２ｇを加えて撹拌し、３０分後に上澄み液のｐＨを測定した。ｐＨの測定は、ｐＨメーター（品名：Ｄ―７２、堀場製作所社製）、ガラス電極（９６１５Ｓ−１０Ｄ、堀場製作所社製）を用いた。改質土壌のｐＨについては下記表１〜４に示す。
<pH>
Based on JGS 0211-2009 "pH test method for soil suspension", 71.2 g of distilled water was added to 18.8 g of modified soil of 7 days old, which had been sealed and cured, and the mixture was stirred. The pH was measured. The pH was measured using a pH meter (product name: D-72, manufactured by HORIBA, Ltd.) and a glass electrode (9615S-10D, manufactured by HORIBA, Ltd.). The pH of the modified soil is shown in Tables 1 to 4 below.
なお、下記表１〜４の各実施例及び各比較例について、コーン指数（材齢時成型）３９０ｋＮ／ｍ２以上、練り返し低下率３５．０％未満、且つ、ｐＨ１０．０未満を満足したものを「〇」として評価した。また、下記表１〜４の各実施例について、コーン指数（材齢時成型）１０００ｋＮ／ｍ２以上、練り返し低下率１５．０％未満、且つ、ｐＨ５．８〜８．６を満足したものを「◎」として評価した。また、練り返し低下率が３５．０％以上のものを「×」として評価した。 For each of the Examples and Comparative Examples in Tables 1 to 4 below, the cone index (molded at the age of the material) of 390 kN / m 2 or more, the kneading reduction rate of less than 35.0%, and the pH of less than 10.0 were satisfied. The thing was evaluated as "○". Further, for each of the examples in Tables 1 to 4 below, the cone index (molded at the age of the material) of 1000 kN / m 2 or more, the kneading reduction rate of less than 15.0%, and the pH of 5.8 to 8.6 were satisfied. Was evaluated as "◎". In addition, those having a kneading reduction rate of 35.0% or more were evaluated as "x".
＜まとめ＞
上記の表１〜４を見ると、各実施例の方が各比較例よりも練り返し低下率が低いことが認められる。つまり、本願発明の構成とすることで、改質土壌を作製して材齢が経過した後に、該改質土壌を練り返しても、改質土壌が発現する強度（コーン指数）が低下するのを抑制することができる。
また、上記の表１を見ると、土壌改質材中の吸水剤の含有量を、二水石膏１００質量部に対して２．１質量部以上とすることで、材齢時成型のコーン指数が高くなることが認められる。つまり、二水石膏１００質量部に対し、吸水剤を２．１質量部以上とすることで、比較的高い強度（コーン指数）を発現する改質土壌を得ることができる。
また、表４の比較例５，６を見ると、材齢時成型のコーン指数が３９０ｋＮ／ｍ２以上であって比較的高い数値であるが、改質土壌のｐＨが１１であることが認められる。つまり、材齢時成型のコーン指数を比較的高くするために、土壌改質材中のアルミナセメントの含有量を増やすと、改質土壌がアルカリ性になることが認められる。これに対し、表１を見ると、二水石膏及びアルミナセメントと、吸水剤とを併用することで、アルミナセメントの含有量を低減しつつ、材齢時成型のコーン指数を高くできることが認められる。つまり、本願発明の構成とすることで、上記のように改質土壌が発現する強度（コーン指数）が低下するのを抑制しつつ、改質土壌のｐＨを１０未満にすることができる。
<Summary>
Looking at Tables 1 to 4 above, it can be seen that each example has a lower rate of reduction in kneading than each comparative example. That is, by adopting the configuration of the present invention, even if the modified soil is prepared and the modified soil is kneaded after the age has passed, the strength (corn index) developed by the modified soil is lowered. Can be suppressed.
Looking at Table 1 above, by setting the content of the water-absorbing agent in the soil modifier to 2.1 parts by mass or more with respect to 100 parts by mass of dihydrate gypsum, the cone index of molding at the age of the material is set. Is found to be higher. That is, by setting the water absorbing agent to 2.1 parts by mass or more with respect to 100 parts by mass of dihydrate gypsum, modified soil exhibiting relatively high strength (corn index) can be obtained.
Further, looking at Comparative Examples 5 and 6 in Table 4, it was confirmed that the pH of the modified soil was 11 although the cone index of molding at the age of the material was 390 kN / m 2 or more, which was a relatively high value. Be done. That is, it is recognized that when the content of alumina cement in the soil reforming material is increased in order to make the cone index of molding at the age of the material relatively high, the reformed soil becomes alkaline. On the other hand, looking at Table 1, it can be seen that by using dihydrate gypsum and alumina cement in combination with a water absorbent, the cone index of molding at the age of the material can be increased while reducing the content of alumina cement. .. That is, by adopting the configuration of the present invention, the pH of the modified soil can be made less than 10 while suppressing the decrease in the strength (corn index) developed by the modified soil as described above.
Claims (6)
二水石膏と、アルミナセメントと、吸水剤とを含んでおり、
二水石膏１００質量部に対し、アルミナセメントを５．３質量部以上４２．９質量部以下、吸水剤を１．２質量部以上、含む、
土壌改質材。 A soil modifier that is mixed with soil to form a modified soil.
Contains dihydrate gypsum, alumina cement, and water absorbent,
(2) Alumina cement is contained in an amount of 5.3 parts by mass or more and 42.9 parts by mass or less and a water absorbent is contained in an amount of 1.2 parts by mass or more with respect to 100 parts by mass of dihydrate gypsum.
Soil modifier.
請求項１に記載の土壌改質材。 Contains 2.1 parts by mass or more of water absorbent,
The soil modifier according to claim 1.
請求項１又は２に記載の土壌改質材。 The water absorbing agent is at least one selected from the group consisting of an anionic polyacrylamide polymer material, a cationic polyacrylamide polymer material, and a nonionic polyacrylamide polymer material.
The soil modifier according to claim 1 or 2.
二水石膏１００質量部に対し、アルミナセメントを５．３質量部以上４２．９質量部以下、吸水剤を１．２質量部以上で混合し、
二水石膏と、アルミナセメントと、吸水剤との合計量１００質量部に対し、土壌を１４００質量部以上２００００質量部以下で混合する、
土壌改質方法。 It is a soil reforming method that forms a modified soil by mixing soil, dihydrate gypsum, alumina cement, and a water absorbent.
Alumina cement is mixed in an amount of 5.3 parts by mass or more and 42.9 parts by mass or less, and a water absorbent is mixed in an amount of 1.2 parts by mass or more with 100 parts by mass of dihydrate gypsum.
The soil is mixed in an amount of 1400 parts by mass or more and 20000 parts by mass or less with respect to 100 parts by mass of the total amount of the dihydrate gypsum, the alumina cement and the water absorbing agent.
Soil reforming method.
二水石膏１００質量部に対し、アルミナセメントを５．３質量部以上４２．９質量部以下、吸水剤を１．２質量部以上、含んでおり、
二水石膏と、アルミナセメントと、吸水剤との合計量１００質量部に対し、土壌を１４００質量部以上２００００質量部以下、含む、
改質土壌。 A modified soil containing soil, dihydrate gypsum, alumina cement, and a water absorbent.
Dihydrate Gypsum contains 5.3 parts by mass or more and 42.9 parts by mass or less of alumina cement and 1.2 parts by mass or more of water absorbent with respect to 100 parts by mass.
(2) Contains 1400 parts by mass or more and 20000 parts by mass or less of soil with respect to 100 parts by mass of the total amount of water gypsum, alumina cement, and water absorbent.
Modified soil.
土壌改質処理工法。 The ground is reformed by hardening the reformed soil according to claim 5 in the ground to form a hardened body.
Soil reforming method.
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| JP2005162949A (en) * | 2003-12-04 | 2005-06-23 | Taiheiyo Material Kk | Grouting material |
| JP2006225475A (en) * | 2005-02-16 | 2006-08-31 | Komurisu:Kk | Solidifier and method for improving solidification of soil by using the solidifier |
| JP2008037934A (en) * | 2006-08-02 | 2008-02-21 | Nippon Shokubai Co Ltd | Wet soil improver, granulation method and granular soil |
| JP2016172651A (en) * | 2015-03-16 | 2016-09-29 | 太平洋セメント株式会社 | Hydraulic powder composition |
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