JP2020158660A - Ground improvement material, improved soil, and method for producing improved soil - Google Patents

Ground improvement material, improved soil, and method for producing improved soil Download PDF

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JP2020158660A
JP2020158660A JP2019060442A JP2019060442A JP2020158660A JP 2020158660 A JP2020158660 A JP 2020158660A JP 2019060442 A JP2019060442 A JP 2019060442A JP 2019060442 A JP2019060442 A JP 2019060442A JP 2020158660 A JP2020158660 A JP 2020158660A
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cement
improved soil
aluminate
soil
ground improvement
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JP7303996B2 (en
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貴宣 佐藤
Takanobu Sato
貴宣 佐藤
吉田 雅彦
Masahiko Yoshida
雅彦 吉田
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Sumitomo Osaka Cement Co Ltd
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    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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Abstract

To provide a ground improvement material or the like that can shorten the time until the expansion of the improved soil converges.SOLUTION: Provided are: a ground improvement material, which is a ground improvement material used by mixing with a target soil and containing a cement-based hydraulic material, and contains aluminate; an improved soil, which is an improved soil containing a target soil and a cement-based hydraulic material, and contains aluminate; and a method for producing improved soil, which is a method for producing improved soil for making an improved soil in which a target soil and a cement-based hydraulic material are mixed, and in which the improved soil contains aluminate.SELECTED DRAWING: Figure 1

Description

本発明は、地盤改良材、改良土、及び、改良土の製造方法に関する。 The present invention relates to a ground improvement material, an improved soil, and a method for producing the improved soil.

従来、道路、構造物等の基礎の強度が不足する場合などには、対象となる土(以下、「対象土」ともいう。)の強度を高めるために、セメントを含むセメント系水硬性材料が含有された地盤改良材と、対象土とを混合して、改良土が作製されている(例えば、特許文献1)。 Conventionally, when the strength of foundations such as roads and structures is insufficient, cement-based hydraulic materials containing cement are used to increase the strength of the target soil (hereinafter, also referred to as "target soil"). An improved soil is produced by mixing the contained ground improving material with the target soil (for example, Patent Document 1).

特開2006−057050号公報Japanese Unexamined Patent Publication No. 2006-057050

前記地盤改良材は、硫酸塩を多く含んでいる。また、地盤改良材と水とを混合して混合物を作製すると水和反応によりエトリンガイトが生成される。
ここで、このエトリンガイトの生成過程では前記混合物は膨張するが、対象土と地盤改良材とを混合して改良土を作製する際には、対象土に間隙があるため、通常は、前記膨張は対象土の間隙により緩和され、改良地盤に変状は生じない。
しかし、対象土に地盤改良材が多く混合されたり、対象土と地盤改良材との混合が不十分で改良土中に地盤改良材が偏って多く含まれる部分が生じたりした場合などには、ごくまれに改良地盤に変状が生じ、改良土の膨張が収束するまで道路や構造物を設ける工事を進めることができず、工期が長くなってしまうことがある。
しかしながら、改良土の膨張が収束するまでの時間を短くすることはこれまで十分に検討がなされていない。
The ground improvement material contains a large amount of sulfate. Further, when a ground improving material and water are mixed to prepare a mixture, ettringite is produced by a hydration reaction.
Here, the mixture expands in the process of forming the ettringite, but when the target soil and the ground improvement material are mixed to prepare the improved soil, the target soil has a gap, so that the expansion usually occurs. It is alleviated by the gaps in the target soil, and no deformation occurs in the improved ground.
However, if a large amount of ground improvement material is mixed in the target soil, or if the target soil and the ground improvement material are not sufficiently mixed and the improved soil contains a large amount of the ground improvement material, etc. In rare cases, the improved ground may be deformed, and the construction of roads and structures may not be able to proceed until the expansion of the improved soil is completed, and the construction period may be lengthened.
However, shortening the time until the expansion of the improved soil converges has not been sufficiently studied so far.

そこで、本発明は、改良土の膨張が収束するまでの時間を短くし得る地盤改良材及び改良土の製造方法、並びに、改良土の膨張が収束するまでの時間が短い改良土を提供することを課題とする。 Therefore, the present invention provides a method for producing a ground improvement material and improved soil that can shorten the time until the expansion of the improved soil converges, and an improved soil that takes a short time until the expansion of the improved soil converges. Is the subject.

本発明者が鋭意研究したところ、特定の化合物を含有する地盤改良材を用いれば、改良土の膨張収束時間を短くし得ることを見出し、本発明を想到するに至った。 As a result of diligent research by the present inventor, he has found that the expansion and convergence time of the improved soil can be shortened by using a ground improvement material containing a specific compound, and came up with the present invention.

すなわち、本発明に係る地盤改良材は、対象土と混合されて用いられ、セメント系水硬性材料を含有する地盤改良材であって、
アルミン酸塩を含有する。
That is, the ground improvement material according to the present invention is a ground improvement material that is mixed with the target soil and contains a cement-based hydraulic material.
Contains aluminate.

ここで、本発明に係る地盤改良材の一態様では、前記アルミン酸塩が、アルミン酸カリウム及びアルミン酸ナトリウムの少なくとも一方を含有する。 Here, in one aspect of the ground improvement material according to the present invention, the aluminate contains at least one of potassium aluminate and sodium aluminate.

また、本発明に係る地盤改良材の他の態様では、前記アルミン酸塩が、アルミン酸カリウムを含有する。 In another aspect of the ground improving material according to the present invention, the aluminate contains potassium aluminate.

さらに、本発明に係る地盤改良材の他の態様では、前記セメント系水硬性材料がSOを含有し、
前記SO100質量部に対して、前記アルミン酸塩が、アルミン酸イオン換算で2.3質量部以上含有されている。
Further, in another aspect of soil improvement material according to the present invention, the cement-based hydraulic material containing SO 3,
The aluminate is contained in an amount of 2.3 parts by mass or more in terms of aluminate ion with respect to 100 parts by mass of SO 3 .

また、本発明に係る改良土は、対象土と、セメント系水硬性材料とを含有する、改良土であって、
アルミン酸塩を含有する。
Further, the improved soil according to the present invention is an improved soil containing a target soil and a cement-based hydraulic material.
Contains aluminate.

さらに、本発明に係る改良土の製造方法は、対象土と、セメント系水硬性材料とが混合された改良土を作製する、改良土の製造方法であって、
前記改良土がアルミン酸塩を含有する。
Further, the method for producing improved soil according to the present invention is a method for producing improved soil in which a target soil and a cement-based hydraulic material are mixed to produce improved soil.
The improved soil contains aluminate.

本発明によれば、改良土の膨張が収束するまでの時間を短くし得る。 According to the present invention, the time until the expansion of the improved soil converges can be shortened.

SOの量に対するアルミン酸イオン換算でのアルミン酸塩の量と、スラリーの膨張が収束するまでの時間(収束日数)との関係を示す図。The figure which shows the relationship between the amount of aluminate in terms of aluminate ion with respect to the amount of SO 3 and the time (the number of days of convergence) until the expansion of a slurry converges.

以下では、本発明の一実施形態について説明する。 Hereinafter, an embodiment of the present invention will be described.

本実施形態に係る地盤改良材は、対象土と混合されて用いられる。
また、本実施形態に係る地盤改良材は、セメント系水硬性材料と、アルミン酸塩とを含有する。
The ground improvement material according to this embodiment is used by being mixed with the target soil.
Further, the ground improvement material according to the present embodiment contains a cement-based hydraulic material and aluminate.

前記対象土は、水を含有する。 The target soil contains water.

前記セメント系水硬性材料は、セメントを含有する。
なお、セメント自体も石膏を含む。
前記セメント系水硬性材料は、前記セメントに含まれる石膏とは別の石膏を含有してもよい。
また、前記セメント系水硬性材料は、高炉スラグを含有してもよい。
前記セメント系水硬性材料は、SOを含有する。
前記セメント系水硬性材料は、SOを、好ましくは5.1〜14.0質量%、より好ましくは7.2〜11.3質量%含有する。
The cement-based hydraulic material contains cement.
The cement itself also contains gypsum.
The cement-based hydraulic material may contain gypsum different from the gypsum contained in the cement.
Further, the cement-based hydraulic material may contain blast furnace slag.
The cement-based hydraulic material contains SO 3 .
The cement-based hydraulic material preferably contains SO 3 in an amount of 5.1 to 14.0% by mass, more preferably 7.2 to 11.3% by mass.

前記セメントは、水硬性セメントである。
前記セメントとしては、例えば、普通、早強、超早強、白色、耐硫酸塩、中庸熱、低熱などの各種ポルトランドセメントが挙げられる。また、前記セメントとしては、例えば、該ポルトランドセメントに高炉スラグ、フライアッシュ、シリカ質混合材(ポゾラン)等を混合してなる混合セメント、アルミナセメントなどの特殊セメントなども挙げられる。
セメント系水硬性材料は、セメントを、好ましくは30〜94質量%、より好ましくは30〜60質量%含有する。
The cement is a hydraulic cement.
Examples of the cement include various Portland cements such as ordinary, early-strength, ultra-fast-strength, white, sulfate-resistant, moderate heat, and low heat. Examples of the cement include mixed cement obtained by mixing Portland cement with blast furnace slag, fly ash, a siliceous mixed material (pozzolan), and special cement such as alumina cement.
The cement-based hydraulic material contains cement in an amount of preferably 30 to 94% by mass, more preferably 30 to 60% by mass.

また、前記セメント系水硬性材料は、セメントに高炉スラグが含まれていることにより、高炉スラグを含有していてもよい。また、前記セメント系水硬性材料は、セメントの高炉スラグとは別の高炉スラグを含有してもよい。 Further, the cement-based hydraulic material may contain blast furnace slag because the cement contains blast furnace slag. Further, the cement-based hydraulic material may contain blast furnace slag different from that of cement blast furnace slag.

前記高炉スラグとしては、高炉水砕スラグ等が挙げられる。
すなわち、セメントの高炉スラグとしては、高炉水砕スラグ等が挙げられ、また、セメントの高炉スラグとは別の高炉スラグとしては、高炉水砕スラグの微粉末等が挙げられる。
高炉水砕スラグの微粉末としては、JIS A 6206:2013の“高炉スラグ微粉末”が好ましく、すなわち、比表面積が2,750cm/g以上10,000cm/g未満のものが好ましい。なお、比表面積は、JIS R 5201:2015の比表面積試験に従って測定することができる。
前記セメント系水硬性材料における高炉スラグの含有割合(セメントの高炉スラグと、セメントの高炉スラグとは別の高炉スラグとの合計の含有割合)は、好ましくは0〜60質量%、より好ましくは25〜51質量%である。
また、高炉スラグは、本実施形態に係る地盤改良材に実質的に含まれなくてもよい。
Examples of the blast furnace slag include blast furnace granulated slag.
That is, examples of the cement blast furnace slag include blast furnace granulated slag, and examples of the blast furnace slag different from the cement blast furnace slag include fine powder of blast furnace granulated slag.
As the fine powder of blast furnace granulated slag, JIS A 6206: 2013 "blast furnace slag fine powder" is preferable, that is, a specific surface area of 2,750 cm 2 / g or more and less than 10,000 cm 2 / g is preferable. The specific surface area can be measured according to the specific surface area test of JIS R 5201: 2015.
The content ratio of blast furnace slag in the cement-based hydrohard material (total content ratio of cement blast furnace slag and blast furnace slag different from cement blast furnace slag) is preferably 0 to 60% by mass, more preferably 25. ~ 51% by mass.
Further, the blast furnace slag may not be substantially included in the ground improvement material according to the present embodiment.

前記石膏としては、無水石膏(CaSO4 )、半水石膏(CaSO4 ・0.5H2 O)、二水石膏(CaSO4 ・2H2 O)等が挙げられる。
すなわち、セメントの石膏としては、無水石膏(CaSO4 )、半水石膏(CaSO4 ・0.5H2 O)、二水石膏(CaSO4 ・2H2 O)等が挙げられ、また、セメントの石膏とは別の石膏としては、無水石膏(CaSO4 )、半水石膏(CaSO4 ・0.5H2 O)、二水石膏(CaSO4 ・2H2 O)等が挙げられる。
前記セメント系水硬性材料における石膏の含有割合(セメントの石膏と、セメントの石膏とは別の石膏との合計の含有割合)は、好ましくは7.4質量%以上、より好ましくは12.6〜25.6質量%、さらにより好ましくは16.2〜25.6質量%である。
As the gypsum, anhydrous gypsum (CaSO 4), hemihydrate gypsum (CaSO 4 · 0.5H 2 O) , gypsum (CaSO 4 · 2H 2 O), and the like.
That is, the gypsum cement, anhydrite (CaSO 4), hemihydrate gypsum (CaSO 4 · 0.5H 2 O) , include gypsum (CaSO 4 · 2H 2 O), etc., and, cement plaster another gypsum and anhydrous gypsum (CaSO 4), hemihydrate gypsum (CaSO 4 · 0.5H 2 O) , gypsum (CaSO 4 · 2H 2 O), and the like.
The content ratio of gypsum in the cement-based hydrohard material (the total content ratio of the cement gypsum and the gypsum different from the cement gypsum) is preferably 7.4% by mass or more, more preferably 12.6 to 1. It is 25.6% by mass, and even more preferably 16.2 to 25.6% by mass.

前記アルミン酸塩としては、アルミン酸カリウム、アルミン酸ナトリウム、アルミン酸リチウム等が挙げられる。
前記アルミン酸塩は、アルミン酸カリウム及びアルミン酸ナトリウムの少なくとも一方を含有することが好ましい。
また、アルミン酸カリウムは、劇物に指定されておらず、取り扱いがしやすいので、前記アルミン酸塩は、アルミン酸カリウムを含有することが特に好ましい。
なお、本実施形態に係る地盤改良材は、アルミン酸塩の水和物が含まれていることにより、アルミン酸を含有していてもよい。
アルミン酸塩の水和物としては、例えば、アルミン酸カリウム・3水和物などが挙げられる。
Examples of the aluminate include potassium aluminate, sodium aluminate, lithium aluminate and the like.
The aluminate preferably contains at least one of potassium aluminate and sodium aluminate.
Further, since potassium aluminate is not designated as a deleterious substance and is easy to handle, it is particularly preferable that the aluminate contains potassium aluminate.
The ground improvement material according to the present embodiment may contain aluminate because it contains hydrate of aluminate.
Examples of the hydrate of the aluminate include potassium aluminate and trihydrate.

本実施形態に係る地盤改良材は、前記SO100質量部に対して、前記アルミン酸塩を、アルミン酸イオン換算で、好ましくは2.3質量部以上、より好ましくは2.3〜90質量部、さらにより好ましくは2.3〜50質量部含有する。 Soil improvement material according to the present embodiment, with respect to the SO 3 100 parts by mass, the aluminate, in aluminate ion conversion, preferably 2.3 parts by mass or more, more preferably 2.3 to 90 mass It is contained in parts, more preferably 2.3 to 50 parts by mass.

なお、本実施形態に係る地盤改良材は、対象土への添加前に全ての成分が混合された状態になっている必要はなく、成分ごとに対象土に添加されてもよい。 The ground improvement material according to the present embodiment does not have to be in a state where all the components are mixed before being added to the target soil, and each component may be added to the target soil.

本実施形態に係る改良土は、対象土と、セメント系水硬性材料とを含有する。また、本実施形態に係る改良土は、アルミン酸塩を含有する。 The improved soil according to the present embodiment contains a target soil and a cement-based hydraulic material. In addition, the improved soil according to this embodiment contains aluminate.

言い換えれば、本実施形態に係る改良土は、対象土と、本実施形態に係る地盤改良材とを含有する。 In other words, the improved soil according to the present embodiment contains the target soil and the ground improvement material according to the present embodiment.

さらに、本実施形態に係る改良土は、対象土の水とは別の水を更に含有してもよい。また、本実施形態に係る改良土は、対象土の水とは別の水を含有しなくてもよく、言い換えれば、水として、対象土の水のみを含有してもよい。 Further, the improved soil according to the present embodiment may further contain water different from the water of the target soil. Further, the improved soil according to the present embodiment does not have to contain water different from the water of the target soil, in other words, the improved soil may contain only the water of the target soil as water.

本実施形態に係る改良土は、湿潤状態の対象土1m当たりのセメント系水硬性材料の量が、好ましくは100〜1100kg/m、より好ましくは400〜1100kg/mである。
また、本実施形態に係る改良土は、乾燥状態の対象土100質量部に対して、セメント系水硬性材料を、好ましくは4.7〜118質量部、より好ましくは18.8〜118質量部含有する。
さらに、本実施形態に係る改良土は、前記セメント系水硬性材料100質量部に対して、対象土の水とは別の水を、好ましくは45〜300質量部、より好ましくは60〜130質量部含有する。
また、本実施形態に係る改良土は、セメント系水硬性材料100質量部に対して、水を(対象土の水、及び、対象土の水とは別に加える水の合計で)、好ましくは19〜960質量部、より好ましくは19〜295質量部含有する。
また、本実施形態に係る改良土は、対象土の水とは別の水を含有する場合、セメント系水硬性材料100質量部に対して、水を(対象土の水、及び、対象土の水とは別に加える水の合計で)、好ましくは60〜960質量部、より好ましくは75〜295質量部含有する。
さらに、本実施形態に係る改良土は、水として、対象土の水のみを含有する場合、セメント系水硬性材料100質量部に対して、水(対象土の水)を、好ましくは19〜654質量部、より好ましくは19〜163質量部含有する。
In the improved soil according to the present embodiment, the amount of the cement-based hydraulic material per 1 m 3 of the target soil in a wet state is preferably 100 to 1100 kg / m 3 , and more preferably 400 to 1100 kg / m 3 .
Further, in the improved soil according to the present embodiment, the cement-based hydraulic material is preferably 4.7 to 118 parts by mass, more preferably 18.8 to 118 parts by mass with respect to 100 parts by mass of the target soil in a dry state. contains.
Further, in the improved soil according to the present embodiment, water different from the water of the target soil is preferably 45 to 300 parts by mass, more preferably 60 to 130 parts by mass with respect to 100 parts by mass of the cement-based hydraulic material. Partly contained.
Further, in the improved soil according to the present embodiment, water is added to 100 parts by mass of the cement-based hydraulic material (total of water of the target soil and water added separately from the water of the target soil), preferably 19. It contains ~ 960 parts by mass, more preferably 19 to 295 parts by mass.
In addition, when the improved soil according to the present embodiment contains water different from the water of the target soil, water is added to 100 parts by mass of the cement-based hydrohard material (water of the target soil and water of the target soil). (In total of water added separately from water), preferably 60 to 960 parts by mass, more preferably 75 to 295 parts by mass.
Further, when the improved soil according to the present embodiment contains only water of the target soil as water, water (water of the target soil) is preferably 19 to 654 with respect to 100 parts by mass of the cement-based hydraulic material. It is contained in parts by mass, more preferably 19 to 163 parts by mass.

本実施形態に係る改良土の製造方法では、対象土と、セメント系水硬性材料とが混合された改良土を作製する。また、前記改良土は、アルミン酸塩を含有する。 In the method for producing improved soil according to the present embodiment, improved soil is prepared by mixing the target soil and a cement-based hydraulic material. In addition, the improved soil contains aluminate.

言い換えれば、本実施形態に係る改良土の製造方法では、対象土と、本実施形態に係る地盤改良材とが混合された改良土を作製する。 In other words, in the method for producing the improved soil according to the present embodiment, the improved soil in which the target soil and the ground improvement material according to the present embodiment are mixed is produced.

本実施形態に係る改良土の製造方法では、改良土を構成する成分をどのような順序で混ぜてもよい。
例えば、本実施形態に係る改良土の製造方法では、本実施形態に係る地盤改良材を構成する成分と、水とを混合してスラリーを作製し、該スラリーと対象土とを混合することにより、改良土を作製してもよい。
また、本実施形態に係る改良土の製造方法では、前記スラリーを経ずに、本実施形態に係る地盤改良材を構成する成分と、水と、対象土とを混合することにより、改良土を作製してもよい。
さらに、本実施形態に係る改良土の製造方法では、対象土の水とは別の水を用いずに、本実施形態に係る地盤改良材を構成する成分と、対象土とを混合することにより、改良土を作製してもよい。
また、本実施形態に係る改良土の製造方法では、本実施形態に係る地盤改良材が、対象土への添加前に全ての成分が混合された状態になっている必要はなく、本実施形態に係る地盤改良材の成分ごとに対象土に添加されてもよい。
In the method for producing improved soil according to the present embodiment, the components constituting the improved soil may be mixed in any order.
For example, in the method for producing improved soil according to the present embodiment, a slurry is prepared by mixing the components constituting the ground improvement material according to the present embodiment with water, and the slurry and the target soil are mixed. , Improved soil may be prepared.
Further, in the method for producing improved soil according to the present embodiment, the improved soil is prepared by mixing the components constituting the ground improvement material according to the present embodiment, water, and the target soil without passing through the slurry. It may be produced.
Further, in the method for producing the improved soil according to the present embodiment, the components constituting the ground improvement material according to the present embodiment and the target soil are mixed without using water different from the water of the target soil. , Improved soil may be prepared.
Further, in the method for producing improved soil according to the present embodiment, it is not necessary that the ground improvement material according to the present embodiment is in a state in which all the components are mixed before being added to the target soil, and the present embodiment Each component of the ground improvement material according to the above may be added to the target soil.

なお、本発明に係る地盤改良材、改良土、及び、改良土の製造方法は、上記実施形態に限定されるものではない。また、本発明に係る地盤改良材、改良土、及び、改良土の製造方法は、上記した作用効果によって限定されるものでもない。さらに、本発明に係る地盤改良材、改良土、及び、改良土の製造方法は、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。 The ground improving material, the improved soil, and the method for producing the improved soil according to the present invention are not limited to the above-described embodiment. Further, the ground improving material, the improved soil, and the method for producing the improved soil according to the present invention are not limited by the above-mentioned action and effect. Further, the ground improving material, the improved soil, and the method for producing the improved soil according to the present invention can be variously changed without departing from the gist of the present invention.

次に、実施例および比較例を挙げて本発明についてさらに具体的に説明する。 Next, the present invention will be described in more detail with reference to Examples and Comparative Examples.

<セメント系水硬性材料>
セメント系水硬性材料としては、下記表1、2のセメント系水硬性材料を作製した。
なお、セメント系水硬性材料におけるSOの含有割合(単に「SOの含有割合」ともいう。)を下記表1、2に示す。
<Cement-based hydraulic material>
As the cement-based hydraulic material, the cement-based hydraulic materials shown in Tables 1 and 2 below were prepared.
The content ratio of SO 3 in the cement-based hydraulic material (also simply referred to as “SO 3 content ratio”) is shown in Tables 1 and 2 below.

Figure 2020158660
Figure 2020158660

Figure 2020158660
Figure 2020158660

<添加剤>
添加剤としては、以下の添加剤を用いた。
・アルミン酸ナトリウム
・アルミン酸カリウム3水和物
・水酸化アルミニウム
<Additives>
The following additives were used as the additives.
・ Sodium aluminate ・ Potassium aluminate trihydrate ・ Aluminum hydroxide

(実施例1)
セメント系水硬性材料としての表1のセメント系水硬性材料Cと、添加剤としてのアルミン酸ナトリウムとを混合して地盤改良材を作製し、該地盤改良材と水とを混合してスラリーを得た。
なお、水は、セメント系水硬性材料100質量部に対して60質量部とした。
また、アルミン酸ナトリウムは、SO100質量部に対して、アルミン酸イオン換算で13.4質量部とした。
(Example 1)
The cement-based hydraulic material C in Table 1 as a cement-based hydraulic material and sodium aluminate as an additive are mixed to prepare a ground improving material, and the ground improving material and water are mixed to prepare a slurry. Obtained.
The amount of water was 60 parts by mass with respect to 100 parts by mass of the cement-based hydraulic material.
The amount of sodium aluminate was 13.4 parts by mass in terms of aluminate ions with respect to 100 parts by mass of SO 3 .

(実施例2)
添加剤としてアルミン酸カリウム・3水和物を用いたこと以外は、実施例1と同様にして、地盤改良材を得、そして、スラリーを得た。
(Example 2)
A ground improving material was obtained and a slurry was obtained in the same manner as in Example 1 except that potassium aluminate trihydrate was used as an additive.

(実施例3)
セメント系水硬性材料としての表2のセメント系水硬性材料Iを用い、アルミン酸ナトリウムの量を、SO100質量部に対してアルミン酸イオン換算で14.4質量部としたこと以外は、実施例1と同様にして、地盤改良材を得、そして、スラリーを得た。
(Example 3)
Except for the fact that the cement-based hydraulic material I in Table 2 was used as the cement-based hydraulic material and the amount of sodium aluminate was 14.4 parts by mass in terms of aluminate ions with respect to 100 parts by mass of SO 3 . A ground improving material was obtained in the same manner as in Example 1, and a slurry was obtained.

(実施例4〜10)
セメント系水硬性材料の種類、及び、アルミン酸塩の量を下記表5に示すものにしたこと以外は、実施例1と同様にして、地盤改良材を得、そして、スラリーを得た。
なお、「アルミン酸塩の量」とは、「SO100質量部に対する、アルミン酸イオン換算でのアルミン酸塩の量(質量部)」を意味する。
(Examples 4 to 10)
A ground improving material was obtained and a slurry was obtained in the same manner as in Example 1 except that the types of cement-based hydraulic materials and the amount of aluminate were as shown in Table 5 below.
The "amount of aluminate" means "amount of aluminate (parts by mass) in terms of aluminate ion with respect to 100 parts by mass of SO 3 ".

(実施例11〜13)
アルミン酸ナトリウムの量を下記表6に示す割合にしたこと以外は、実施例1と同様にして、地盤改良材を得、そして、スラリーを得た。
(Examples 11 to 13)
A ground improving material was obtained and a slurry was obtained in the same manner as in Example 1 except that the amount of sodium aluminate was set to the ratio shown in Table 6 below.

(比較例1)
添加剤として水酸化アルミニウムを用いたこと以外は、実施例1と同様にして、地盤改良材を得、そして、スラリーを得た。
なお、添加剤の量については、SOの量に対する、アルミニウム換算での添加剤の量が実施例1と同じとなるようにした。
(Comparative Example 1)
A ground improving material was obtained and a slurry was obtained in the same manner as in Example 1 except that aluminum hydroxide was used as an additive.
Regarding the amount of the additive, the amount of the additive in terms of aluminum with respect to the amount of SO 3 was set to be the same as in Example 1.

(比較例2)
添加剤を用いなかったこと以外は、実施例1と同様にして、地盤改良材を得、そして、スラリーを得た。
(Comparative Example 2)
A ground improving material was obtained and a slurry was obtained in the same manner as in Example 1 except that no additive was used.

(比較例3)
添加剤を用いなかったこと以外は、実施例3と同様にして、地盤改良材を得、そして、スラリーを得た。
(Comparative Example 3)
A ground improving material was obtained and a slurry was obtained in the same manner as in Example 3 except that no additive was used.

<膨張変化試験>
実施例及び比較例のスラリーを型枠に打設し、打設後24時間で脱型し、直方体の供試体(寸法:40mm×40mm×160mm(最長部分))を得た。
そして、供試体を20℃の水の中で養生した。また、水中養生直前を基準(材齢0日)とし、水中養生を開始してから10日までは約1日おきに、14日後からは約7日おきに、最長部分の長さ変化を膨張変化の指標として測定した。
最長部分の長さ変化は、JIS A1129−3:2010「モルタル及びコンクリートの長さ変化測定方法‐第3部:ダイヤルゲージ方法」に準じて測定した。
また、長さ変化率に関し、前回(1回前)に測定した長さ変化率との比較において、長さ変化率の1日当たりの増加量が、0.01%/日以下になった場合に、前回の測定時における材齢を収束日数(膨張が収束するまでの日数)とした。
すなわち、N回目の測定時における、長さ変化率の1日当たりの増加量は、下記式(1)で求め、この増加量が0.01%/日以下になった場合に、(N−1)回目の測定時における材齢を収束日数とした。
N回目の測定時における、長さ変化率の1日当たりの増加量(%/日) = (N回目に測定した長さ変化率(%) − (N−1)回目に測定した長さ変化率(%))/(N回目の測定時における材齢(日) − (N−1)回目の測定時における材齢(日))・・・(1)
収束日数について、実施例1、2及び比較例1、2の結果を下記表3に、実施例3及び比較例3の結果を下記表4に、実施例1、4〜10の結果を表5に、実施例1、11〜13及び比較例1の結果を表6に、実施例1、2、4〜12の結果を図1に示す。
<Expansion change test>
The slurries of Examples and Comparative Examples were cast into a mold and demolded 24 hours after the casting to obtain a rectangular parallelepiped specimen (dimensions: 40 mm × 40 mm × 160 mm (longest portion)).
Then, the specimen was cured in water at 20 ° C. In addition, based on the standard immediately before underwater curing (0 days of material age), the length change of the longest part is expanded every other day until 10 days after the start of underwater curing, and every 7 days after 14 days. It was measured as an index of change.
The length change of the longest part was measured according to JIS A1129-3: 2010 "Mortar and concrete length change measurement method-Part 3: Dial gauge method".
In addition, regarding the length change rate, when the amount of increase in the length change rate per day is 0.01% / day or less in comparison with the length change rate measured last time (one time before). , The age at the time of the previous measurement was defined as the number of days of convergence (the number of days until the expansion converges).
That is, the daily increase in the length change rate at the Nth measurement is calculated by the following formula (1), and when this increase is 0.01% / day or less, (N-1). ) The age at the time of the second measurement was defined as the number of days of convergence.
Increase in length change rate per day at the Nth measurement (% / day) = (Length change rate measured at the Nth measurement (%)-(N-1) Length change rate measured at the Nth measurement (%)) / (Material age at the Nth measurement (day)-(N-1) Material age at the time of the Nth measurement (day)) ... (1)
Regarding the number of days of convergence, the results of Examples 1 and 2 and Comparative Examples 1 and 2 are shown in Table 3 below, the results of Example 3 and Comparative Example 3 are shown in Table 4 below, and the results of Examples 1 and 4 to 10 are shown in Table 5. The results of Examples 1, 11 to 13 and Comparative Example 1 are shown in Table 6, and the results of Examples 1, 2, 4 to 12 are shown in FIG.

Figure 2020158660
Figure 2020158660

Figure 2020158660
Figure 2020158660

Figure 2020158660
Figure 2020158660

表3、4に示すように、早強ポルドランドセメントを含むセメント系水硬性材料のみからなる比較例2、普通ポルドランドセメントを含むセメント系水硬性材料のみからなる比較例3の地盤改良材を用いた場合で、42日後まで膨張が継続していた。
このことから、セメント系水硬性材料と水との反応(水和反応)による生成物であるエトリンガイトが、改良土の膨張の要因と考えられる。
As shown in Tables 3 and 4, the ground improvement materials of Comparative Example 2 composed of only cement-based hydraulic material containing early-strength Portland cement and Comparative Example 3 consisting of only cement-based hydraulic material containing ordinary Portland cement were used. When used, swelling continued until 42 days later.
From this, it is considered that ettringite, which is a product of the reaction (hydration reaction) between the cement-based hydraulic material and water, is the cause of the expansion of the improved soil.

表3に示すように、実施例1、2の地盤改良材を用いた場合では、添加剤として水酸化アルミニウムを用いた比較例1の地盤改良材、添加剤を用いなかった比較例2の地盤改良材を用いた場合に比べて、収束日数が短かった。
また、表4に示すように、実施例3の地盤改良材を用いた場合では、添加剤を用いなかった比較例3の地盤改良材を用いた場合に比べて、収束日数が短かった。
また、表5に示すように、実施例1〜3と異なるセメント系水硬性材料を用いた実施例4〜10の地盤改良材を用いた場合でも、収束日数は短かった。
以上の結果から、エトリンガイトの生成反応が改良土の膨張の要因となっており、反応性に富むアルミニウム塩であるアルミン酸塩が存在すると、早期にエトリンガイトの生成反応が終結して、改良土の膨張が収束するまでの時間を短くすることができると考えられる。
したがって、本発明によれば、改良土の膨張が収束するまでの時間を短くし得ることがわかる。
As shown in Table 3, when the ground improvement materials of Examples 1 and 2 were used, the ground improvement material of Comparative Example 1 in which aluminum hydroxide was used as an additive and the ground of Comparative Example 2 in which no additive was used. The number of days of convergence was shorter than when the improved material was used.
Further, as shown in Table 4, when the ground improvement material of Example 3 was used, the number of days of convergence was shorter than that of the case where the ground improvement material of Comparative Example 3 in which no additive was used was used.
Further, as shown in Table 5, even when the ground improvement materials of Examples 4 to 10 using cement-based hydraulic materials different from those of Examples 1 to 3 were used, the number of days of convergence was short.
From the above results, the ettringite formation reaction is a factor in the expansion of the improved soil, and in the presence of aluminate, which is a highly reactive aluminum salt, the ettringite formation reaction is terminated early and the improved soil It is considered that the time until the expansion converges can be shortened.
Therefore, according to the present invention, it can be seen that the time until the expansion of the improved soil converges can be shortened.

Figure 2020158660
Figure 2020158660

表6、図1に示すように、SOに対するアルミン酸イオン換算での前記アルミン酸塩の量が多いほど、収束日数が短かった。
このことから、SOに対するアルミン酸イオン換算での前記アルミン酸塩の量が多いほど、改良土の膨張が収束するまでの時間を短くし得ることがわかる。
Table 6, as shown in FIG. 1, as the amount of the aluminate in the aluminate ion in terms relative to SO 3 is large, the convergence of days was short.
Therefore, as the amount of the aluminate in the aluminate ion in terms relative to SO 3 is large, it can be seen that the expansion of the modified soil can shorten the time to converge.

Claims (6)

対象土と混合されて用いられ、セメント系水硬性材料を含有する地盤改良材であって、
アルミン酸塩を含有する、地盤改良材。
A ground improvement material that is mixed with the target soil and contains a cement-based hydraulic material.
Ground improvement material containing aluminate.
前記アルミン酸塩が、アルミン酸カリウム及びアルミン酸ナトリウムの少なくとも一方を含有する、請求項1に記載の地盤改良材。 The ground improving material according to claim 1, wherein the aluminate contains at least one of potassium aluminate and sodium aluminate. 前記アルミン酸塩が、アルミン酸カリウムを含有する、請求項2に記載の地盤改良材。 The ground improving material according to claim 2, wherein the aluminate contains potassium aluminate. 前記セメント系水硬性材料がSOを含有し、
前記SO100質量部に対して、前記アルミン酸塩が、アルミン酸イオン換算で2.3質量部以上含有されている、請求項1〜3の何れか1項に記載の地盤改良材。
The cement-based hydraulic material contains SO 3 and
The ground improvement material according to any one of claims 1 to 3, wherein the aluminate is contained in an amount of 2.3 parts by mass or more in terms of aluminate ion with respect to 100 parts by mass of SO 3 .
対象土と、セメント系水硬性材料とを含有する、改良土であって、
アルミン酸塩を含有する、改良土。
An improved soil containing the target soil and a cement-based hydraulic material.
Improved soil containing aluminate.
対象土と、セメント系水硬性材料とが混合された改良土を作製する、改良土の製造方法であって、
前記改良土がアルミン酸塩を含有する、改良土の製造方法。
A method for producing improved soil in which the target soil and a cement-based hydraulic material are mixed.
A method for producing improved soil, wherein the improved soil contains aluminate.
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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0940950A (en) * 1995-07-28 1997-02-10 Kyokado Eng Co Ltd Method for stabilizing soft ground
JPH1046145A (en) * 1996-08-07 1998-02-17 Kyokado Eng Co Ltd Grout for ground
WO2006051875A1 (en) * 2004-11-11 2006-05-18 Denki Kagaku Kogyo Kabushiki Kaisha Composition for ground-improving material, grouting material comprising the same, and method of using the same
JP2015229684A (en) * 2014-06-03 2015-12-21 株式会社菱晃 Hardening material, hardening material liquid, agent for soil property stabilization, production method of the agent and ground stabilization method
JP2017008249A (en) * 2015-06-24 2017-01-12 宇部興産株式会社 Sol improver and soil improvement method

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0940950A (en) * 1995-07-28 1997-02-10 Kyokado Eng Co Ltd Method for stabilizing soft ground
JPH1046145A (en) * 1996-08-07 1998-02-17 Kyokado Eng Co Ltd Grout for ground
WO2006051875A1 (en) * 2004-11-11 2006-05-18 Denki Kagaku Kogyo Kabushiki Kaisha Composition for ground-improving material, grouting material comprising the same, and method of using the same
JP2015229684A (en) * 2014-06-03 2015-12-21 株式会社菱晃 Hardening material, hardening material liquid, agent for soil property stabilization, production method of the agent and ground stabilization method
JP2017008249A (en) * 2015-06-24 2017-01-12 宇部興産株式会社 Sol improver and soil improvement method

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