JP2004052536A - Solidification material for soil-based paving - Google Patents

Solidification material for soil-based paving Download PDF

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Publication number
JP2004052536A
JP2004052536A JP2003139365A JP2003139365A JP2004052536A JP 2004052536 A JP2004052536 A JP 2004052536A JP 2003139365 A JP2003139365 A JP 2003139365A JP 2003139365 A JP2003139365 A JP 2003139365A JP 2004052536 A JP2004052536 A JP 2004052536A
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Japan
Prior art keywords
soil
mass
pavement
based pavement
earth
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JP2003139365A
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Japanese (ja)
Inventor
Seiki Saito
齋藤 成輝
Hiroteru Maenami
前浪 洋輝
Masatsugu Miura
三浦 正嗣
Noribumi Isu
井須 紀文
Hideki Ishida
石田 秀輝
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Inax Corp
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Inax Corp
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  • Soil Conditioners And Soil-Stabilizing Materials (AREA)

Abstract

<P>PROBLEM TO BE SOLVED: To provide soil-based pavement which has an excellent design property, high durability and enough strength or the like, on which pedestrians hardly become tired, and which does not cause a heat island phenomenon. <P>SOLUTION: The solidification material for soil-based paving is mixed with soil to make mixed soil, which is uniformly laid over the place to be paved, and then is rolled and cured to form the soil-based pavement 3. The hardening material for soil-based paving includes slaked lime and slag, but does not include a porous material. <P>COPYRIGHT: (C)2004,JPO

Description

【0001】
【発明が属する技術分野】
本発明は土系舗装用固化材に関する。
【0002】
【従来の技術】
一般的な舗装は、路床上に施工された路盤と、この路盤の上方に施工されて路面を仕上げる表層とからなる。路盤は、砕石等により構成されており、舗装の上面からの押圧力により表層が変形したり、破壊したりすることを防止している。他方、従来の表層は、アスファルトやコンクリートを現場で施工し、これらを固化することにより構成され得る。また、表層は、コンクリートからなるインターロッキングブロック等を路盤上に施工することによっても構成され得る。こうして施工された舗装は、アスファルト等が高い強度及び硬度を有し、かつこれらが路盤に支持されていることから、高い耐久性を発揮することができる。
【0003】
一方、特許文献1には、炭ガラ、軽石又は煉瓦からなる多孔質材料と、セメント、消石灰又は生石灰及び石膏からなる土質安定剤と、粘土質の土とを混合してなる透水性土質改良材が開示されている。この透水性土質改良材を路床上に施工すれば、透水性を有し、かつ表層の強度を低下しない路盤を得ることができる。このため、その路盤上の表層を透水性のあるアスファルト等とすれば、路面上に表面水が溜まり難いという効果を奏することができる。
【0004】
【特許文献1】
特開平11−71582号公報
【0005】
【発明が解決しようとする課題】
しかし、上記従来の一般的な舗装は、その上を主に自動車が通行する場合を考慮して構成されていることから、いかにも人工的すぎ、その上を主に人が歩く場合には、その歩行者が疲れやすいという指摘がある。また、表層がアスファルトやコンクリートからなる従来の舗装は夏場に路面の温度が上がりやすく、ヒートアイランド現象を生じてしまうという欠点もある。このため、少なくとも表層を自然の土だけで構成することも考えられるが、こうすると、自然の土だけでは強度等が低すぎることから、路面が変形しやすく、耐久性に欠けるという欠点を生じる。
【0006】
この点、上記公報記載の透水性土質改良材から粘土質の土を除いた残部を固化材と考え、この固化材を現場の土と混合して混合土とし、その混合土を舗装場所に敷きならした後、転圧及び養生して表層とすることも考えられる。こうすれば、自然の土がその表層を構成していることから、歩行者が疲れにくく、ヒートアイランド現象を生じない表層になると考えられる。しかしながら、その透水性土質改良材は元々その上に別に表層が施工される路盤を構成するためのものであり、この透水性土質改良材から得られた固化材では、表層の耐久性が極めて劣るものとなってしまう。すなわち、仮にその固化材によって表層を施工するとしても、その固化材には必ず多孔質材料が含まれることとなり、そうして得られる表層は、強度が著しく劣るものとなり、かつ多孔質材料の気孔に浸透する水によって冬季の霜害等に犯され易いものとなってしまう。
【0007】
本発明は、上記従来の実情に鑑みてなされたものであって、意匠性に優れるとともに、十分な強度等を有して高い耐久性を発揮しつつ、歩行者が疲れにくく、ヒートアイランド現象を生じない土系舗装を提供することを解決すべき課題としている。
【0008】
【課題を解決するための手段】
発明者らは、上記課題解決のために鋭意研究を行い、多孔質材料を含むことなく、消石灰とスラグとを含む土系舗装用固化材を用いれば、これを土と混合した混合土として舗装場所に敷きならした後に転圧及び養生することにより、意匠性に優れるとともに、十分な強度等を有して高い耐久性を発揮しつつ、歩行者が疲れにくい土系舗装が得られることを発見し、本発明を完成するに至った。
【0009】
すなわち、本発明の土系舗装用固化材は、土と混合されて混合土となり、舗装場所に敷きならされた該混合土が転圧及び養生されて土系舗装となる土系舗装用固化材であって、多孔質材料を含まず、消石灰とスラグとを含むことを特徴とする。
【0010】
本発明の土系舗装用固化材は各地に存在する土と混合されて混合土となる。この混合土は、舗装場所に敷きならされ、転圧により締め固められ、養生により土系舗装となる。この土系舗装は自然の土の雰囲気がそのまま残り、優れた意匠を呈する。
【0011】
土系舗装は、路床上に直接施工されてもよいが、路床上に路盤となる砕石等を施工した後、この路盤上に施工されることが好ましい。上面からの押圧力により土系舗装が変形したり、破壊したりすることを路盤が防止するからである。
【0012】
発明者らの試験結果によれば、土、消石灰及びスラグを含む混合土は、常温下で固化が進行し、従来のアスファルト等からなるものほど高くなく、自然の土だけからなるものほど低くない強度及び硬度を有して固化する。
【0013】
つまり、消石灰は常温下で炭酸カルシウム(CaCO)を生成する(炭酸化反応)。土は、消石灰及びスラグとともに、常温下で水和反応してCSH(CxSyHz;xCaO・ySiO・zHOの意である。x、y及びzは固体水和物として存在し得る正数。)、CAH(CxAyHz;xCaO・yAl・zHOの意である。x、y及びzは固体水和物として存在し得る正数。)、CASH(CwAxSyHz;wCaO・xAl・ySiO・zHOの意である。w、x、y及びzは固体水和物として存在し得る正数。)等の固体水和物を生成する(水和反応)。この固体水和物は、CSH、CAH、CASH等におけるCa、Si又はAlの一部がアルカリ金属、アルカリ土類金属、非金属元素又は遷移元素と置換されたものである場合もあり得る。これら消石灰、土及びスラグは混合されてなることから、両反応は同時期又はほぼ同時期に進行し、互いに他方の反応を促進し合うと考えられる。また、これらの反応により生じる炭酸カルシウムと固体水和物とは、一方が他方の相間を補強し合ったり、新たな固体水和物を生じたりして土系舗装になると考えられる。新たな固体水和物は、結晶である場合の他、非結晶である場合もあり得、土、消石灰及びスラグから生じる炭酸カルシウム及び固体水和物の中間的な組成を有する場合もあり得る。
【0014】
スラグはCASH系水和物の固化後の強度を上げ、土系舗装の耐摩耗性を向上させるとともに、成形後の歩行できない期間である養生期間を短縮する。特に、スラグは水和物の生成を促進し、土系舗装にローモンタイト(Laumontite)等を形成し、これに強固な結合に由来する耐摩耗性・耐久性を付与する。ローモンタイトは、理想的にはCaAlSi1648・16HOの化学組成を持つゼオライト鉱物の一種であり、天然産は濁沸石と呼ばれている。また、スラグの添加により、冬季の霜害等に対する耐久性が得られる。発明者らの試験結果によれば、スラグは平均粒径が55μm未満であることが好ましい。スラグの平均粒径が55μm以上であると、強度低下により耐久性が低下するからである。なお、スラグは、セメント用に産出されることにより、石膏を含有するものであってもよい。
【0015】
また、本発明に係る土系舗装は、フリーデル氏塩及び/又は炭酸水和物、エトリンジャイト(ettringite)、モノサルフェート(monosalfate(Calcium Aluminium Oxide Sulfite Hydrate))等も強度発現成分になり得ると考えられる。
【0016】
発明者らの試験結果によれば、本発明の土系舗装用固化材が塩化ナトリウム(NaCl)、塩化マグネシウム(MgCl)、塩化カルシウム(CaCl)等の塩化物を含めば、土系舗装がフリーデル氏塩を含む。
【0017】
発明者らの試験結果によれば、フリーデル氏塩は3CaO・Al・xCaCl・yHO(xは3又は1、yは1、6、10又は30)である。このフリーデル氏塩は、0°C未満では3CaO・Al・3CaCl・30HOが安定相であり、0〜28°Cではα−3CaO・Al・CaCl・10HOが安定相であり、28〜200°Cではβ−3CaO・Al・CaCl・10HOが安定相であり、200〜500°Cでは3CaO・Al・CaCl・6HOが安定相であり、500°Cを超えると3CaO・Al・CaCl・HOが安定相である。このため、常温下で土系舗装が得られることから、特に3CaO・Al・CaCl・10HOが強度発現成分として大きく寄与すると考えられる。これらのフリーデル氏塩は、密度(真比重)が2.1〜2.2g/cm程度であり、土中に含まれる密度(真比重)が2.6〜2.8g/cm程度の石英や長石に比べて小さく、嵩高い物質であることから、土系舗装における粒子間を埋めることによる強度向上の効果が期待されるからである。
【0018】
発明者らの知見によれば、フリーデル氏塩は、NaCl又はCaClの水溶液(電解液)により、以下のように生成される。まず、AFm(セメント鉱物の1種であり、alminate ferrite monoの略)構造の[CaAl(OH)・2HO]の相間に水溶液中のClが吸着し、Clの存在がバインディングの役割を果たす。そして、AFm構造の[CaAl(OH)・2HO]に存在するOHとClとがイオン交換され、Clの存在がさらにバインディングの役割を果たす。
【0019】
また、発明者らの知見によれば、CaClを添加する方がNaClを添加するよりも、Clのバインディングの効果が大きい。また、CaClは水に対する溶解度が大きく、溶解したCa2+はCa(OH)の析出を起こし、残されたClがAFm構造の[CaAl(OH)・2HO]の相間に吸着又はイオン交換して容易にバインダとなり得る。さらに、CaClを添加すれば、Ca2+がCa(OH)を析出する際にOHを消費するため、系全体のpHを下げる。また、CSH系の化合物(ゲル)が共存する場合、チャージバランスをとるためにCa2+やNaがCSH中に取り込まれる。
【0020】
他方、発明者らの試験結果によれば、本発明の土系舗装用固化材が塩化ナトリウム(NaCl)、塩化マグネシウム(MgCl)、塩化カルシウム(CaCl)等の塩化物を含まなければ、土系舗装が炭酸水和物を含む。また、土系舗装用固化材が塩化物とともにAl(OH)を含む場合、土系舗装が炭酸水和物も生成する傾向がある。発明者らの試験結果によれば、炭酸水和物は3CaO・Al・CaCO・11HOである。
【0021】
本発明の土系舗装用固化材が石膏、ミョウバン等の硫酸塩化合物を含めば、土系舗装がエトリンジャイト、モノサルフェートを含む。エトリンジャイトは低比重(ρ=1.74g/cm)と結晶形状に由来する膨張性を持ち、固化体の収縮を抑制する性質と早強材としての性質とを有することが知られている。
【0022】
モノサルフェートは結合剤として機能し、比較的低比重(ρ=2.1g/cm)の結晶質であることが知られている。但し、本発明に係る土系舗装においてコンクリートがら等を再生骨材とする場合には、この土系舗装中には再生骨材中のセメント鉱物水和物が含まれることとなるが、その場合でもその再生骨材中に未水和のCS等の鉱物が含まれていない限り、かかるセメント鉱物水和物はその土系舗装の強度発現成分たり得ない。
【0023】
また、本発明の土系舗装用固化材は、炭ガラ等の多孔質材料を含まないため、得られる土系舗装は、強度が比較的高く維持され、かつ多孔質材料の気孔に浸透する水による冬季の霜害等のおそれがない。
【0024】
このため、土系舗装の上を主に人が歩く場合、その歩行者が疲れにくい。また、こうして得られる土系舗装は、意匠性に優れるとともに、十分な強度によって路面の変形がさほど大きくなく、かつ冬季の霜害等のおそれも少ないことから、優れた耐久性を発揮する。さらに、こうして得られる土系舗装は、表層がアスファルトやコンクリートからなる舗装に比し、夏場に路面の温度が上がりにくく、ヒートアイランド現象を生じない。
【0025】
したがって、この土系舗装用固化材によれば、意匠性に優れるとともに、十分な強度等を有して高い耐久性を発揮しつつ、歩行者が疲れにくく、ヒートアイランド現象を生じない土系舗装を提供することができる。
【0026】
また、この土系舗装用固化材を採用すれば、各地に存在する土を採用して舗装が得られるため、舗装場所にわざわざアスファルト等を用意する必要がなく、流通コストを大幅に削減でき、製造コストの低廉化を実現できる。また、この舗装用固化材は、土系舗装を得るために無機系廃棄物の一種であるスラグを採用していることから、環境適合性に優れ、かつ製造コストの低廉化を実現する。
【0027】
土は各地に存在するものを採用することができる。発明者らの試験結果によれば、Alが7〜17質量%、アルカリ金属酸化物又は/及びアルカリ土類金属酸化物が2〜10質量%、灼熱減量が1〜6質量%、SiOが実質残部の組成を有する原料の粉末であることが好ましい。実質とはFe、TiO等を含み得る意である。
【0028】
発明者らが確認した結果、この原料の粉末としては、風化した花崗岩の粉末(マサ土、砂婆土、ヘナ土ともいう。)として得ることができる。風化した花崗岩の粉末は、アルカリ金属酸化物としてはNaO及びKOを含み、アルカリ土類金属酸化物としてはCaO及びMgOを含む。なお、アルカリ金属酸化物としてLiOを含むもの、アルカリ土類金属酸化物としてBeO、SrO又はBaOを含むものも採用し得る。また、Fe、TiOを含むものも採用し得る。風化した花崗岩の粉末の主な構成相は、粉末X線回折装置(RIGAKU RAD−B)を用いたXRD観察によれば、石英、ソーダ長石、正長石、雲母、カオリン鉱物及び緑泥石である。また、この粉末は角閃石を構成相として含むこともできる。
【0029】
発明者らが確認した結果、花崗岩の粉末は風化の程度の小さいものであることが土系舗装の強度確保の点で好ましい。風化とは、風雨や気温の変化等の影響及び植物やバクテリアの存在により岩石が変質し、分解される過程である。この風化は構成相の部分的な粘土化として表れていると考えられる。構成相の部分的な粘土化は、まず大きな粒径の粉末の表面で水和物の生成を生じ、これにより小さな粒径の粉末を生じ、さらに全体の粉末の表面で水和物を生じて進行していくものと考えられる。Iglossが粉末に存在する水和物の量を相対的に示すと考えられ、Iglossの量が多い程、風化が進行していると考えられる。また、発明者らがTG−DTA観察により上記花崗岩の粉末の脱水挙動を確認した結果、60°C付近及び150°C付近にピークをもつ脱水反応が得られたことから、これら花崗岩の粉末の風化は粉末の表面にハロイサイト又はモンモリロナイトを生成することで進行していると考えられる。
【0030】
このため、本発明の土系舗装用固化材は粘土を含むことが好ましい。アルカリ土類水酸化物の他の原料の粉末として、SiO、Al並びにアルカリ金属酸化物又は/及びアルカリ土類金属酸化物を種々の原料の粉末により上記組成範囲を構成するとともに、土系舗装用固化材中のカオリナイト等の粘土により上記組成範囲を構成することもできると考えられるからである。これにより、土系舗装用固化材の粘土がスラグとともにポゾラン物質としてローモンタイト等の水和物を土系舗装に生じ、強度が発現される。また、土系舗装用固化材が粘土を含めば、施工時に土系舗装の粒子に粘性を付与することができ、締め固めの力が有効に作用して十分な締め固め状態が得られ、土系舗装が十分な強度を発揮する。
【0031】
本発明の土系舗装用固化材は、発明者らの試験結果によれば、100質量部の消石灰と、28.6〜100質量部のスラグとを含むことが好ましい。上記風化した花崗岩の粉末が多量に産出されるのは、日本の国土の1/10程度であり、消石灰とスラグとがこの範囲内であれば、日本全国ほとんど全ての地域で産出される土により土系舗装が得られる。土系舗装用固化材中のスラグが28.6質量部未満では、土系舗装に冬季の耐候性と早期供用のために必要な強度を付与し難い。他方、土系舗装用固化材中のスラグが100質量部を超えると、全体に占める細粒分の比率が大きくなり過ぎて施工性が悪化するとともに、強度の増加率が減少して増加の効果を期待できない。
【0032】
本発明の土系舗装用固化材が粘土を含む場合、発明者らの試験結果によれば、100質量部の消石灰と、28.6〜100質量部のスラグと、14.3〜100質量部の粘土とを含むことがより好ましい。各地で産出される土には通常シルト以下分の細粒分が20質量%以上含まれており、土系舗装用固化材中の粘土が14.3質量部未満では、施工前の混合土に粘性を持たせ難い。土にシルト以下分の細粒分が20質量%以上含まれている場合には、土系舗装用固化材中の粘土の含有率を可及的に小さくすることができる。他方、土系舗装用固化材中の粘土が100質量部を超えれば、混合土の混練が不十分になりやすいとともに、粘土のもつ自由水の吸放出により土系舗装がクラックを発生し、土系舗装の機能が損なわれやすい。また、土系舗装用固化材中の粘土が100質量部を超えれば、全体に占める細粒分の比率が大きくなり過ぎ、施工性が悪化する。
【0033】
また、本発明の土系舗装用固化材は、発明者らの試験結果によれば、含水率が5質量%以下であることが好ましい。土系舗装用固化材の含水率が5質量%以下であれば、土と混合される前であっても、長期に亘って消石灰の炭酸化やスラグの水和をほとんど生じず、土系舗装用固化材の品質劣化を生じ難いからである。本発明の土系舗装用固化材は含水率が2質量%以下であることがより好ましい。土系舗装用固化材の含水率が2質量%以下であれば、1年以上に亘って品質劣化を生じ難い。本発明の土系舗装用固化材は、含水率がこの範囲内に入るような消石灰及びスラグを用いることが好ましいのである。土系舗装用固化材が粘土を含む場合、その粘土が産出時に空気中の水分によって20〜50質量%の水分を含むのであれば、一旦その粘土を乾燥させて含水率を10質量%程度以下としてから、消石灰及びスラグと混合することが好ましい。
【0034】
本発明の土系舗装用固化材は顔料を含むことができる。これにより、土系舗装を着色することができる。顔料は、100質量部の土系舗装用固化材において、10質量部未満でも足りる。顔料は比較的高価であり、10質量部以上含んでも土系舗装の色調に顕著な差が現れないからである。
【0035】
土は、礫分と砂分とシルト分と粘土分とからなり、最大乾燥密度が1.4g/cm以上であるとともに最大乾燥密度が得られる含水率が5〜30質量%であり、かつシルト分と粘土分との合計が40質量%以下のものであることが好ましい。礫分は粒径が2000μmを超えるものである。細砂、中砂及び粗砂からなる砂分は粒径が74μmを超え、2000μm以下のものである。シルト分は粒径が5μmを超え、74μm以下のものである。粘土分は粒径が5μm以下のものである。なお、土は、舗装場所で産出される単一のものだけでなく、他のものと混合されたものでもよい。発明者らの試験結果によれば、土がこの条件を満たせば、本発明の土系舗装用固化材により歩行者用歩道としての土系舗装が十分な強度を発揮する。土は、最大乾燥密度が得られる含水率が7〜20質量%の土を用いることがより好ましい。また、土は、シルト分と粘土分との合計が25質量%以下のものであることがより好ましい。シルト分と粘土分との合計が15質量%以下の土を用いることがさらに好ましい。シルト以下分が25質量%を超える土の場合、砕石等の礫分や砂分を混合し、シルト以下分が25質量%以下、好ましくは15質量%以下にすることができる。
【0036】
本発明の土系舗装用固化材は、乾燥時の100質量部の混合土に7〜25質量部含まれることが好ましい。土系舗装用固化材が7質量部以上であれば施工後7日の一軸圧縮強度が2.0MPaを超え、雑草も生じない。土系舗装用固化材が20質量部を超えれば、強度増加率が緩やかになる。
【0037】
なお、土系舗装は骨材を含むことができる。骨材としては、コンクリートがら、陶磁器がら、カレット等の無機廃棄物を採用することができる。また、土系舗装の透水性を向上させるため、混合物に多孔質材を混合することもできる。この多孔質材としては、ALCがら等の発泡コンクリートがら、軽石、レンガ屑等の多くの気泡をもった材料を採用することができる。こうして得られる土系舗装は透水性を発揮する。気泡が連続気泡であれば、より土系舗装が透水性を発揮しやすい。
【0038】
【発明の実施の形態】
以下、本発明を具体化した実施例1〜5及び試験例1〜10を図面を参照しつつ説明する。
【0039】
(実施例1)
[調合工程]
まず、工場内において、消石灰(工業用1号)と粘土と高炉水砕スラグとを用意する。
【0040】
消石灰の組成を表1に示し、その特性を表2に示し、その粒度分布を表3及び図2に示す。また、粘土の組成を表4に示し、その粒度分布を図2に示す。粘土の耐火度は、JIS R 2204に準拠すれば、SK26である。さらに、スラグの組成を含む特性を表5に示し、その粒度分布を表6及び図2に示す。なお、試験値1、2はロットの相違を示す。
【0041】
【表1】

Figure 2004052536
【0042】
【表2】
Figure 2004052536
【0043】
【表3】
Figure 2004052536
【0044】
【表4】
Figure 2004052536
【0045】
【表5】
Figure 2004052536
【0046】
【表6】
Figure 2004052536
【0047】
そして、100質量部の消石灰と、50質量部の粘土と、50質量部のスラグとを混合し、土系舗装用固化材とする。この土系舗装用固化材の組成を表7に示す。
【0048】
【表7】
Figure 2004052536
【0049】
得られた土系舗装用固化材は、CaOが69〜79質量%、Alが5.5〜7.5質量%及びSiOが10〜15質量%であり、含水率が2.0質量%以下であり、異物の混入がないものである。
【0050】
[施工工程]
そして、図1に示すように、土系舗装を施工せんとする舗装現場を15cm程掘削し、路床1を得る。これにより、土が用意される。この路床1上にC−40の砕石等を敷き詰め、路盤2を施工する。そして、以下のように、路盤2の上方に土系舗装3を施工する。
【0051】
まず、現場において、調合工程で混合した土系舗装用固化材を土に添加する。この際、80質量部の土に対し、20質量部の土系舗装用固化材を添加する。これらを水とともに混合し、混合土を得る。そして、混合土を路盤2の上方に敷き詰め、ロードローラ等で所定の密度まで転圧する。この後、この上にシートを被せ、7日間養生する。こうして、従来のアスファルト等からなるものほど高くなく、自然の土だけからなるものほど低くない曲げ強度、圧縮強度及び硬度を有して固化した土系舗装3を得る。この土系舗装は自然の土の雰囲気がそのまま残り、優れた意匠を呈する。
【0052】
この土系舗装3は、圧縮強度が30〜40kgf/cm、乾燥密度が1.8〜2.0g/cmであった。また、この土系舗装3は、ゴルフボールを高さ1mの高さから垂直に落下させ、一次反発した高さを示すGB値が60であった。コンクリート系舗装はGB値が59、密粒アスファルト系舗装はGB値が60であることから、土系舗装3は十分な強度を有していることがわかる。一方、この土系舗装3は、直径1cmの鋼球を高さ1mの高さから垂直に落下させ、一次反発した高さを示すSB値が1であった。コンクリート系舗装はSB値が4、密粒アスファルト系舗装はSB値が3であることから、土系舗装3は、衝撃に対してやさしいことがわかる。また、この土系舗装3は、透水係数が踏み固められた土と同程度の10−4〜10−5cm/秒、保水性が約0.2g/cmであった。このため、この土系舗装は冬季の霜害等のおそれがない。
【0053】
また、こうして得られる土系舗装3と、密粒アスファルト系舗装と、コンクリート系舗装と、外気温との関係を調べた。結果を図3に示す。図3より、土系舗装3は、表層がアスファルトやコンクリートからなる舗装に比し、夏場に路面の温度が上がりにくいことがわかる。
【0054】
このため、この土系舗装3の上を主に人が歩く場合、その歩行者が疲れにくい。また、こうして得られる土系舗装は、意匠性に優れるとともに、十分な強度によって路面の変形がさほど大きくなく、かつ冬季の霜害等のおそれも少ないことから、優れた耐久性を発揮する。さらに、こうして得られる土系舗装は、表層がアスファルトやコンクリートからなる舗装に比し、夏場に路面の温度が上がりにくく、ヒートアイランド現象を生じない。
【0055】
したがって、この土系舗装用固化材によれば、意匠性に優れるとともに、十分な強度等を有して高い耐久性を発揮しつつ、歩行者が疲れにくく、ヒートアイランド現象を生じない土系舗装を提供することができる。
【0056】
また、この土系舗装用固化材を採用すれば、舗装場所にわざわざ風化した花崗岩の粉末を用意する必要がなく、流通コストを大幅に削減でき、製造コストの低廉化を実現できる。また、この舗装用固化材は、土系舗装3を得るために無機系廃棄物の一種であるスラグを採用していることから、環境適合性に優れ、かつ製造コストの低廉化を実現する。
【0057】
(実施例2)
実施例2では、100質量部の消石灰と、80質量部の粘土と、100質量部のスラグと、25質量部の顔料とを混合し、土系舗装用固化材とする。この土系舗装用固化材の組成を表8に示す。この際、100質量部の土に対し、17.6質量部の土系舗装用固化材を添加する。そして、実施例1と同様に土系舗装3を施工する。この土系舗装3は、着色されて優れた美観を呈する他、実施例1と同様の作用効果を奏する。
【0058】
【表8】
Figure 2004052536
【0059】
(実施例3)
実施例3では、100質量部の消石灰と、80質量部の粘土と、100質量部のスラグと、20質量部の顔料とを混合し、土系舗装用固化材とする。この土系舗装用固化材の組成を表9に示す。この際、100質量部の土に対し、7.5質量部の土系舗装用固化材を添加する。そして、実施例1と同様に土系舗装3を施工する。この土系舗装3においても実施例2と同様の作用効果を奏する。
【0060】
【表9】
Figure 2004052536
【0061】
(実施例4)
実施例4では、100質量部の消石灰と、80質量部の粘土と、100質量部のスラグと、20質量部の顔料とを混合し、土系舗装用固化材とする。この土系舗装用固化材の組成を表10に示す。この際、100質量部の土に対し、11.1質量部の土系舗装用固化材を添加する。そして、実施例1と同様に土系舗装3を施工する。この土系舗装3においても実施例2と同様の作用効果を奏する。
【0062】
【表10】
Figure 2004052536
【0063】
(実施例5)
実施例5では、100質量部の消石灰と、90質量部の粘土と、100質量部のスラグと、20質量部の顔料とを混合し、土系舗装用固化材とする。この土系舗装用固化材の組成を表11に示す。そして、実施例1と同様に土系舗装3を施工する。この土系舗装3においても実施例2と同様の作用効果を奏する。
【0064】
【表11】
Figure 2004052536
【0065】
なお、他のスラグを用意した。このスラグの組成を表12に示す。このスラグによっても同様の効果が得られる。
【0066】
【表12】
Figure 2004052536
【0067】
また、粒度の異なる高炉スラグ(新日鐵中部エスメント(株))を用意した。各スラグの粒度分布を表13及び図4に示す。平均粒径30μmの細粒のスラグは実施例1〜5に係るスラグと同様の効果を奏することができたものの、平均粒径55μmの粗粒のスラグは強度低下により耐久性が低下する点で好ましくない結果が得られた。
【0068】
【表13】
Figure 2004052536
【0069】
(試験例1〜10)
表14に示すように、礫土、マサ土、砂質土又は粘性土からなる各土が掘削される現場において、土系舗装用固化材の割合を変えるとともに、土と土系舗装用固化材との割合も変え、実施例1と同様に土系舗装を施工する。試験例1の礫土は篩い下分を含む市販の砕石原土である。試験例2〜7のマサ土は細粒分混じりの礫質砂である。砕石は単粒度砕石6号(5−13)である。土のシルト分と粘土分との合計(質量%)も表14に示す(※1)。また、消石灰、粘土及びスラグは上記実施例1のものであり、消石灰100質量部に対する(※2)、粘土の割合(※3)及びスラグの割合(※4)も示す。
【0070】
【表14】
Figure 2004052536
【0071】
得られた土系舗装の一軸圧縮強度(MPa)及び評価を表15に示す。評価の△は冬季に霜害を生じ、路面に部分的な剥離を生じたものである。評価の○はこのような剥離を生じず、実施例1と同様に優れた耐久性を示したものである。また、各土の最大乾燥密度(g/cm)及び最大乾燥密度が得られる含水率(質量%)も表15に示す。
【0072】
【表15】
Figure 2004052536
【0073】
表15より、試験例1〜6、8の条件下で施工した土系舗装であれば、施工後7日の一軸圧縮強度が2.0MPaを超え、歩行者用歩道として十分な強度を発揮することがわかる。また、試験例7の条件下で施工した土系舗装では、土95質量部に対して土系舗装用固化材5.1質量部が含まれているに過ぎないため、施工後7日の一軸圧縮強度が低く、歩行者用歩道として十分な強度を発揮できないことがわかる。一方、試験例9、10の条件下で施工した土系舗装は、シルト以下分が多く、耐久性に劣ることがわかる。
【図面の簡単な説明】
【図1】実施例1〜5に係る土系舗装の模式断面図である。
【図2】実施例1〜5に係る消石灰、粘土及びスラグの粒度分布を示すグラフである。
【図3】実施例1〜5に係る土系舗装の路面の温度を比較して示すグラフである。
【図4】スラグの粒度分布を示すグラフである。
【符号の説明】
1…路床
2…路盤
3…土系舗装[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a solidification material for earth-based pavement.
[0002]
[Prior art]
A general pavement includes a roadbed constructed on a roadbed, and a surface layer constructed above the roadbed to finish a road surface. The roadbed is made of crushed stone or the like, and prevents the surface layer from being deformed or broken by the pressing force from the upper surface of the pavement. On the other hand, a conventional surface layer can be constructed by applying asphalt or concrete on site and solidifying them. In addition, the surface layer can also be configured by constructing an interlocking block or the like made of concrete on a roadbed. The pavement thus constructed can exhibit high durability because asphalt and the like have high strength and hardness and are supported by the roadbed.
[0003]
On the other hand, Patent Literature 1 discloses a water-permeable soil improving material obtained by mixing a porous material made of charcoal, pumice or brick, a soil stabilizer made of cement, slaked lime or quicklime and gypsum, and a clay soil. Is disclosed. If this permeable soil improving material is applied on a roadbed, a roadbed having water permeability and not reducing the strength of the surface layer can be obtained. For this reason, if the surface layer on the roadbed is made of water-permeable asphalt or the like, the effect that surface water hardly accumulates on the road surface can be obtained.
[0004]
[Patent Document 1]
JP-A-11-71582
[0005]
[Problems to be solved by the invention]
However, since the conventional general pavement is configured in consideration of a case where a car mainly passes on the pavement, it is extremely artificial, and when a person mainly walks on the pavement, the There are indications that pedestrians tend to get tired. Further, the conventional pavement whose surface layer is made of asphalt or concrete has a drawback that the temperature of the road surface easily rises in summer and a heat island phenomenon occurs. For this reason, it is conceivable that at least the surface layer is composed of only natural soil. However, in this case, since the strength and the like of only natural soil are too low, the road surface is likely to be deformed and lacks durability.
[0006]
In this regard, the remaining portion of the permeable soil improving material described in the above-mentioned publication except for the clay soil is considered as a solidified material, and this solidified material is mixed with soil at the site to form a mixed soil, and the mixed soil is laid on a pavement site. After smoothing, it is also conceivable to roll and cure to form a surface layer. In this case, since the natural soil forms the surface layer, the pedestrian is less likely to be tired and the surface layer does not cause the heat island phenomenon. However, the permeable soil improving material is originally for constituting a roadbed on which a surface layer is separately constructed, and the solidified material obtained from this permeable soil improving material has extremely poor durability of the surface layer. It will be something. In other words, even if the surface layer is constructed with the solidified material, the solidified material always contains a porous material, and the surface layer obtained in this way has extremely poor strength, and the porous material has pores. Water that penetrates the water easily becomes susceptible to frost damage in winter.
[0007]
The present invention has been made in view of the above-mentioned conventional circumstances, and is excellent in design, while having sufficient strength and the like and exhibiting high durability, pedestrians are hardly tired, and the heat island phenomenon occurs. Providing no soil-based pavement is an issue to be solved.
[0008]
[Means for Solving the Problems]
The present inventors have conducted intensive studies to solve the above-mentioned problems, and if a soil-based pavement hardening material containing slaked lime and slag is used without including a porous material, the soil is mixed with soil to form a pavement. We found that by rolling and curing after laying in a place, it is possible to obtain earth-based pavement that is excellent in design, has sufficient strength, etc., exhibits high durability, and makes pedestrians less tired Thus, the present invention has been completed.
[0009]
That is, the solidified pavement solidifying material of the present invention is mixed with soil to form a mixed soil, and the mixed soil laid on the pavement site is compacted and cured to form an soil-based pavement. , Characterized by containing slaked lime and slag without containing a porous material.
[0010]
The soil-based pavement solidifying material of the present invention is mixed with soil existing in various places to form a mixed soil. This mixed soil is spread on a pavement site, compacted by compaction, and cured to form an earth-based pavement. This earth-based pavement retains the natural atmosphere of the earth and exhibits an excellent design.
[0011]
The earth-based pavement may be constructed directly on the subgrade, but is preferably constructed on the subgrade after constructing crushed stone or the like as a subgrade on the subgrade. This is because the roadbed prevents the earth-based pavement from being deformed or broken by the pressing force from the upper surface.
[0012]
According to the test results of the inventors, soil, mixed lime containing slaked lime and slag, solidification proceeds at room temperature, is not as high as that of conventional asphalt, and not as low as that of only natural soil. Solidifies with strength and hardness.
[0013]
In other words, slaked lime is calcium carbonate (CaCO 3 ) (Carbonation reaction). The soil, together with slaked lime and slag, undergoes a hydration reaction at room temperature to produce CSH (CxSyHz; xCaO.ySiO). 2 ・ ZH 2 It stands for O. x, y and z are positive numbers that can exist as a solid hydrate. ), CAH (CxAyHz; xCaO.yAl) 2 O 3 ・ ZH 2 It stands for O. x, y and z are positive numbers that can exist as a solid hydrate. ), CASH (CwAxSyHz; wCaO.xAl) 2 O 3 ・ YSiO 2 ・ ZH 2 It stands for O. w, x, y and z are positive numbers that can exist as solid hydrates. ) And the like (hydration reaction). This solid hydrate may be one in which Ca, Si or Al in CSH, CAH, CASH or the like is partially replaced with an alkali metal, an alkaline earth metal, a nonmetal element, or a transition element. Since these slaked lime, soil and slag are mixed, it is considered that both reactions proceed at the same time or almost at the same time and promote the other reaction with each other. In addition, calcium carbonate and solid hydrate generated by these reactions are considered to be earth-based pavements, as one reinforces the other phase or generates a new solid hydrate. The new solid hydrate may be crystalline or non-crystalline, and may have an intermediate composition of calcium carbonate and solid hydrate from soil, slaked lime and slag.
[0014]
The slag increases the strength of the CASH-based hydrate after solidification, improves the abrasion resistance of the soil-based pavement, and shortens the curing period, which is a period during which it is impossible to walk after forming. In particular, slag promotes the formation of hydrates, forms laumontite or the like on earth-based pavement, and gives it abrasion resistance and durability derived from strong bonding. Lomontite is ideally Ca 4 Al 8 Si 16 O 48 ・ 16H 2 It is a type of zeolite mineral having the chemical composition of O, and its natural product is called turbidolite. In addition, the durability against frost damage in winter can be obtained by adding slag. According to the test results of the inventors, the slag preferably has an average particle size of less than 55 μm. This is because if the average particle size of the slag is 55 μm or more, the durability decreases due to a decrease in strength. The slag may contain gypsum by being produced for cement.
[0015]
Further, the soil-based pavement according to the present invention is considered that Friedel's salt and / or carbonate hydrate, ettringite, monosulfate (Calmium Aluminum Oxide Sulfite Hydrate), and the like can also be strength-expressing components. Can be
[0016]
According to the test results of the inventors, the solidification material for the earth-based pavement of the present invention is sodium chloride (NaCl), magnesium chloride (MgCl). 2 ), Calcium chloride (CaCl 2 ), The soil pavement contains Friedel's salt.
[0017]
According to the test results of the inventors, Friedel's salt is 3CaO.Al 2 O 3 XCaCl 2 ・ YH 2 O (x is 3 or 1, y is 1, 6, 10, or 30). This Friedel salt is 3CaO.Al below 0 ° C. 2 O 3 ・ 3CaCl 2 ・ 30H 2 O is a stable phase, and at 0 to 28 ° C., α-3CaO.Al 2 O 3 ・ CaCl 2 ・ 10H 2 O is a stable phase, and at 28 to 200 ° C., β-3CaO.Al 2 O 3 ・ CaCl 2 ・ 10H 2 O is a stable phase, and 3CaO.Al 2 O 3 ・ CaCl 2 ・ 6H 2 O is a stable phase, and 3CaO.Al 2 O 3 ・ CaCl 2 ・ H 2 O is the stable phase. For this reason, since soil-based pavement can be obtained at room temperature, 3CaO.Al 2 O 3 ・ CaCl 2 ・ 10H 2 It is considered that O greatly contributes as a strength developing component. These Friedel salts have a density (true specific gravity) of 2.1 to 2.2 g / cm. 3 And the density (true specific gravity) contained in the soil is 2.6 to 2.8 g / cm. 3 This is because the material is small and bulky as compared with quartz and feldspar, and an effect of improving the strength by filling the space between the particles in the soil-based pavement is expected.
[0018]
According to the inventors' knowledge, Friedel's salt is NaCl or CaCl 2 Is produced as follows by an aqueous solution (electrolyte solution) of First, a [Ca] having an AFm (a kind of cement mineral, abbreviated as “almit ferrite mono”) structure 2 Al (OH) 6 ・ 2H 2 O] + Cl in aqueous solution during the phase of Is adsorbed and Cl Plays the role of binding. [Ca of the AFm structure] 2 Al (OH) 6 ・ 2H 2 O] + OH present in And Cl Is ion-exchanged with Cl Presence further serves as a binding.
[0019]
According to the findings of the inventors, CaCl 2 Is better than adding NaCl. The binding effect is great. In addition, CaCl 2 Has high solubility in water, 2+ Is Ca (OH) 2 And the remaining Cl Is [Ca] of the AFm structure 2 Al (OH) 6 ・ 2H 2 O] + Can easily become a binder by adsorption or ion exchange between the phases. Further, CaCl 2 Is added, Ca 2+ Is Ca (OH) 2 OH To reduce the pH of the entire system. When a CSH-based compound (gel) coexists, Ca is added to balance the charge. 2+ And Na + Is taken into CSH.
[0020]
On the other hand, according to the test results of the inventors, the solidification material for the earth-based pavement of the present invention is sodium chloride (NaCl), magnesium chloride (MgCl). 2 ), Calcium chloride (CaCl 2 ), The soil pavement contains carbonate hydrate. In addition, the solidification material for earth-based pavement is made of Al (OH) together with chloride. 3 When the soil-based pavement contains carbonic acid hydrate, it tends to form. According to the test results of the inventors, carbonate hydrate is 3CaO.Al 2 O 3 ・ CaCO 3 ・ 11H 2 O.
[0021]
If the solidification material for earth-based pavement of the present invention includes a sulfate compound such as gypsum or alum, the earth-based pavement includes ettringite and monosulfate. Ettringite has a low specific gravity (ρ = 1.74 g / cm 3 ) And an expandability derived from the crystal shape, and is known to have a property of suppressing shrinkage of the solidified body and a property as an early-strength material.
[0022]
Monosulfate functions as a binder and has a relatively low specific gravity (ρ = 2.1 g / cm 3 ) Is known to be crystalline. However, when the concrete pavement or the like is used as the recycled aggregate in the soil-based pavement according to the present invention, the cement-based mineral hydrate in the recycled aggregate is included in the soil-based pavement. But unhydrated C in the recycled aggregate 2 As long as minerals such as S are not included, such cement mineral hydrate cannot be a strength-developing component of the earth-based pavement.
[0023]
Further, since the solidification material for soil-based pavement of the present invention does not include a porous material such as coal waste, the obtained soil-based pavement has a relatively high strength and is capable of retaining water that penetrates into pores of the porous material. There is no danger of frost damage in winter due to
[0024]
Therefore, when a person mainly walks on the soil-based pavement, the pedestrian is less likely to be tired. Moreover, the earth-based pavement thus obtained exhibits excellent durability because the road surface is not so much deformed due to sufficient strength and there is little possibility of frost damage in winter season. Furthermore, the soil-based pavement obtained in this way is less likely to raise the temperature of the road surface in summer and does not cause a heat island phenomenon, as compared with a pavement whose surface layer is made of asphalt or concrete.
[0025]
Therefore, according to the solidification material for soil-based pavement, the soil-based pavement that is excellent in designability, has sufficient strength and the like and exhibits high durability, and is hard for pedestrians to be tired and does not cause a heat island phenomenon. Can be provided.
[0026]
In addition, if this soil-based pavement solidifying material is used, pavement can be obtained by using soil existing in various places, so there is no need to prepare asphalt or the like on the pavement site, and distribution costs can be greatly reduced. Manufacturing cost can be reduced. In addition, since the solidification material for pavement employs slag, which is a kind of inorganic waste, to obtain an earth-based pavement, it is excellent in environmental compatibility and realizes a reduction in manufacturing cost.
[0027]
Soil that exists in various places can be adopted. According to the test results of the inventors, Al 2 O 3 7 to 17% by mass, alkali metal oxide and / or alkaline earth metal oxide 2 to 10% by mass, loss on ignition 1 to 6% by mass, SiO 2 Is preferably a raw material powder having a substantially residual composition. Real is Fe 2 O 3 , TiO 2 And the like.
[0028]
As a result of confirmation by the inventors, powder of this raw material can be obtained as powder of weathered granite (also referred to as masa earth, sand sand, and henna earth). Weathered granite powder contains Na as an alkali metal oxide. 2 O and K 2 O, and the alkaline earth metal oxides include CaO and MgO. Note that Li is used as an alkali metal oxide. 2 Those containing O and those containing BeO, SrO or BaO as an alkaline earth metal oxide can also be adopted. Also, Fe 2 O 3 , TiO 2 May be employed. The main constituent phases of the weathered granite powder are quartz, soda feldspar, feldspar, mica, kaolin mineral, and chlorite according to XRD observation using a powder X-ray diffractometer (RIGAKU RAD-B). The powder may also include amphibole as a constituent phase.
[0029]
As a result of the confirmation by the inventors, it is preferable that the granite powder has a small degree of weathering from the viewpoint of securing the strength of the earth-based pavement. Weathering is a process in which rocks are altered and decomposed due to the effects of wind and rain, changes in temperature, etc., and the presence of plants and bacteria. This weathering is considered to be manifested as partial clayification of the constituent phases. Partial claying of the constituent phases firstly results in the formation of hydrates on the surface of the larger particle size powder, thereby producing a smaller particle size powder, and furthermore on the surface of the whole powder. It is thought to proceed. It is considered that Igloss relatively indicates the amount of hydrate present in the powder, and it is considered that the greater the amount of Igloss, the more weathering has progressed. In addition, as a result of the inventors confirming the dehydration behavior of the granite powder by TG-DTA observation, a dehydration reaction having peaks at around 60 ° C. and around 150 ° C. was obtained. It is considered that weathering is proceeding by forming halloysite or montmorillonite on the surface of the powder.
[0030]
For this reason, it is preferable that the solidification material for earth-based pavement of the present invention contains clay. As a powder of another raw material of the alkaline earth hydroxide, SiO 2 2 , Al 2 O 3 In addition, the above composition range is composed of alkali metal oxides and / or alkaline earth metal oxides by powders of various raw materials, and the above composition range is composed of clay such as kaolinite in a solidification material for earth-based pavement. It is thought that it can be done. As a result, the clay of the solidification material for the earth-based pavement forms a hydrate such as lomontite as a pozzolanic substance on the soil-based pavement together with the slag, and the strength is developed. In addition, if the solidification material for soil-based pavement includes clay, viscosity can be imparted to the particles of the soil-based pavement during construction, and the compaction force works effectively to obtain a sufficient compaction state. Pavement exhibits sufficient strength.
[0031]
According to the test results of the inventors, it is preferable that the solidified pavement hardening material of the present invention contains 100 parts by mass of slaked lime and 28.6 to 100 parts by mass of slag. A large amount of the weathered granite powder is produced in about one-tenth of Japan's land, and if slaked lime and slag are within this range, the soil produced in almost all regions of Japan An earth-based pavement is obtained. If the amount of slag in the solidified material for soil-based pavement is less than 28.6 parts by mass, it is difficult to provide the soil-based pavement with the weather resistance in winter and the strength required for early service. On the other hand, if the amount of slag in the solidified pavement for earth-based pavement exceeds 100 parts by mass, the proportion of fine particles in the whole becomes too large, thereby deteriorating the workability, and the rate of increase in strength decreases, thereby increasing the effect. Can not expect.
[0032]
When the solidification material for soil-based pavement of the present invention contains clay, according to the test results of the inventors, 100 parts by mass of slaked lime, 28.6 to 100 parts by mass of slag, and 14.3 to 100 parts by mass. More preferably. Soil produced in various places usually contains 20% by mass or more of fine particles less than silt. If the clay in the solidification material for soil-based pavement is less than 14.3 parts by mass, It is difficult to have viscosity. When the soil contains 20% by mass or more of the fine particles equivalent to the silt or less, the content of the clay in the solidified pavement hardening material can be reduced as much as possible. On the other hand, if the amount of the clay in the solidification material for the earth-based pavement exceeds 100 parts by mass, the kneading of the mixed soil tends to be insufficient, and the soil-based pavement generates cracks by absorbing and releasing the free water of the clay. The function of the pavement is easily damaged. On the other hand, if the amount of the clay in the solidification material for the earth-based pavement exceeds 100 parts by mass, the proportion of fine particles in the whole becomes too large, and the workability deteriorates.
[0033]
Further, according to the test results of the inventors, the solidified material for earth-based pavement of the present invention preferably has a water content of 5% by mass or less. If the water content of the solidification material for soil-based pavement is 5% by mass or less, almost no carbonation of slaked lime or hydration of slag occurs for a long time even before being mixed with soil, and soil-based pavement This is because the quality of the solidified material for use hardly deteriorates. It is more preferable that the solidification material for earth-based pavement of the present invention has a water content of 2% by mass or less. If the moisture content of the solidification material for earth-based pavement is 2% by mass or less, quality deterioration hardly occurs for one year or more. It is preferable to use slaked lime and slag such that the moisture content falls within this range for the solidified pavement hardening material of the present invention. When the soil-based pavement solidifying material contains clay, if the clay contains 20 to 50% by mass of water due to the moisture in the air at the time of production, the clay is dried once to reduce the water content to about 10% by mass or less. And then mixed with slaked lime and slag.
[0034]
The solidification material for earth-based pavement of the present invention can contain a pigment. Thereby, the soil-based pavement can be colored. The pigment may be less than 10 parts by mass in 100 parts by mass of the solidified pavement material for soil pavement. This is because pigments are relatively expensive, and even if they are contained in an amount of 10 parts by mass or more, there is no significant difference in the color tone of the earth-based pavement.
[0035]
The soil consists of gravel, sand, silt, and clay, and has a maximum dry density of 1.4 g / cm. 3 As described above, it is preferable that the water content at which the maximum dry density is obtained is 5 to 30% by mass, and the sum of the silt content and the clay content is 40% by mass or less. The gravel has a particle size exceeding 2000 μm. The sand composed of fine sand, medium sand and coarse sand has a particle size exceeding 74 μm and not more than 2000 μm. The silt component has a particle size exceeding 5 μm and not more than 74 μm. The clay component has a particle size of 5 μm or less. The soil is not limited to a single soil produced at a pavement site, but may be a mixture of other soils. According to the test results of the inventors, if the soil satisfies this condition, the soil-based pavement as a pedestrian sidewalk exhibits a sufficient strength by the solidified material for soil-based pavement of the present invention. As the soil, it is more preferable to use a soil having a water content of 7 to 20% by mass for obtaining a maximum dry density. It is more preferable that the soil has a total of a silt content and a clay content of 25% by mass or less. It is more preferable to use soil in which the total of the silt content and the clay content is 15% by mass or less. In the case of soil having a silt content of more than 25% by mass, gravel or sand such as crushed stone can be mixed to make the silt or less content 25% by mass or less, preferably 15% by mass or less.
[0036]
The solidified pavement hardening material of the present invention is preferably contained in an amount of 7 to 25 parts by mass in 100 parts by mass of the mixed soil upon drying. If the solidification material for soil-based pavement is 7 parts by mass or more, the uniaxial compressive strength on the 7th day after construction exceeds 2.0 MPa, and no weeds are generated. If the amount of the solidification material for the earth-based pavement exceeds 20 parts by mass, the rate of increase in strength becomes slow.
[0037]
The soil pavement can include aggregate. As the aggregate, concrete waste, ceramic waste, cullet, or other inorganic waste can be used. Further, in order to improve the water permeability of the earth-based pavement, a porous material can be mixed into the mixture. As the porous material, a material having many bubbles, such as foam concrete, such as ALC, pumice, and brick debris can be used. The soil pavement thus obtained exhibits water permeability. If the cells are open cells, the soil-based pavement is more likely to exhibit water permeability.
[0038]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, Examples 1 to 5 and Test Examples 1 to 10 that embody the present invention will be described with reference to the drawings.
[0039]
(Example 1)
[Formulation process]
First, slaked lime (industrial No. 1), clay, and granulated blast furnace slag are prepared in a factory.
[0040]
The composition of slaked lime is shown in Table 1, its properties are shown in Table 2, and its particle size distribution is shown in Table 3 and FIG. The composition of the clay is shown in Table 4, and the particle size distribution is shown in FIG. The fire resistance of the clay is SK26 according to JIS R 2204. Further, the characteristics including the composition of the slag are shown in Table 5, and the particle size distribution is shown in Table 6 and FIG. Note that the test values 1 and 2 indicate differences between lots.
[0041]
[Table 1]
Figure 2004052536
[0042]
[Table 2]
Figure 2004052536
[0043]
[Table 3]
Figure 2004052536
[0044]
[Table 4]
Figure 2004052536
[0045]
[Table 5]
Figure 2004052536
[0046]
[Table 6]
Figure 2004052536
[0047]
Then, 100 parts by mass of slaked lime, 50 parts by mass of clay, and 50 parts by mass of slag are mixed to obtain a solidification material for earth-based pavement. Table 7 shows the composition of the solidified pavement hardening material.
[0048]
[Table 7]
Figure 2004052536
[0049]
The obtained solidification material for earth-based pavement contains 69 to 79% by mass of CaO, 2 O 3 Is 5.5 to 7.5% by mass and SiO 2 Is 10 to 15% by mass, the water content is 2.0% by mass or less, and no foreign matter is mixed.
[0050]
[Construction process]
Then, as shown in FIG. 1, a pavement site where soil-based pavement is to be constructed is excavated by about 15 cm to obtain a subgrade 1. Thereby, soil is prepared. C-40 crushed stones and the like are spread on the subgrade 1 and the subgrade 2 is constructed. Then, the earth-based pavement 3 is constructed above the roadbed 2 as described below.
[0051]
First, at the site, the soil-based pavement solidifying material mixed in the preparation process is added to the soil. At this time, 20 parts by mass of the solidification material for soil-based pavement is added to 80 parts by mass of soil. These are mixed with water to obtain a mixed soil. Then, the mixed soil is spread over the roadbed 2 and rolled to a predetermined density by a load roller or the like. Thereafter, a sheet is put on the sheet and cured for 7 days. In this way, the solid pavement 3 having a flexural strength, a compressive strength and a hardness that is not as high as that of conventional asphalt or the like and not as low as that of only natural soil is obtained. This earth-based pavement retains the natural atmosphere of the earth and exhibits an excellent design.
[0052]
This earth-based pavement 3 has a compressive strength of 30 to 40 kgf / cm. 2 , Dry density 1.8-2.0 g / cm 3 Met. In addition, in this earth-based pavement 3, the golf ball was dropped vertically from a height of 1 m, and the GB value indicating the primary rebound height was 60. Since the concrete-based pavement has a GB value of 59 and the dense-grained asphalt-based pavement has a GB value of 60, it is understood that the soil-based pavement 3 has a sufficient strength. On the other hand, in this soil-based pavement 3, a steel ball having a diameter of 1 cm was vertically dropped from a height of 1 m, and the SB value indicating the height of the primary repulsion was 1. Since the concrete pavement has an SB value of 4 and the dense asphalt pavement has an SB value of 3, it can be seen that the soil pavement 3 is easy to impact. In addition, the soil-based pavement 3 has a hydraulic conductivity of about 10 which is almost equal to that of the compacted soil. -4 -10 -5 cm / sec, water retention about 0.2g / cm 3 Met. For this reason, this soil-based pavement is free from the possibility of frost damage in winter.
[0053]
In addition, the relationship between the thus obtained soil pavement 3, dense-grained asphalt pavement, concrete pavement, and the outside temperature was examined. The results are shown in FIG. From FIG. 3, it can be seen that the soil-based pavement 3 is less likely to raise the temperature of the road surface in summer than the pavement whose surface layer is made of asphalt or concrete.
[0054]
Therefore, when a person mainly walks on the earth-based pavement 3, the pedestrian is less likely to be tired. Moreover, the earth-based pavement thus obtained exhibits excellent durability because the road surface is not so much deformed due to sufficient strength and there is little possibility of frost damage in winter season. Furthermore, the soil-based pavement obtained in this way is less likely to raise the temperature of the road surface in summer and does not cause a heat island phenomenon, as compared with a pavement whose surface layer is made of asphalt or concrete.
[0055]
Therefore, according to the solidification material for soil-based pavement, the soil-based pavement that is excellent in designability, has sufficient strength and the like and exhibits high durability, and is hard for pedestrians to be tired and does not cause a heat island phenomenon. Can be provided.
[0056]
In addition, if this soil-based pavement hardening material is employed, it is not necessary to prepare a weathered granite powder at the pavement site, so that distribution costs can be significantly reduced and production costs can be reduced. Further, since the solidification material for pavement employs slag, which is a kind of inorganic waste, to obtain the earth-based pavement 3, it is excellent in environmental compatibility and realizes a reduction in manufacturing cost.
[0057]
(Example 2)
In Example 2, 100 parts by mass of slaked lime, 80 parts by mass of clay, 100 parts by mass of slag, and 25 parts by mass of pigment are mixed to obtain an earth-based pavement solidifying material. Table 8 shows the composition of the solidification material for earth-based pavement. At this time, 17.6 parts by mass of the solidification material for soil pavement is added to 100 parts by mass of soil. Then, the soil pavement 3 is constructed as in the first embodiment. The soil-based pavement 3 is colored and presents an excellent aesthetic appearance, and has the same operational effects as those of the first embodiment.
[0058]
[Table 8]
Figure 2004052536
[0059]
(Example 3)
In Example 3, 100 parts by mass of slaked lime, 80 parts by mass of clay, 100 parts by mass of slag, and 20 parts by mass of pigment are mixed to obtain a solidification material for an earth-based pavement. Table 9 shows the composition of the solidification material for earth-based pavement. At this time, 7.5 parts by mass of the solidification material for soil pavement is added to 100 parts by mass of the soil. Then, the soil pavement 3 is constructed as in the first embodiment. This soil-based pavement 3 also has the same operation and effect as the second embodiment.
[0060]
[Table 9]
Figure 2004052536
[0061]
(Example 4)
In Example 4, 100 parts by mass of slaked lime, 80 parts by mass of clay, 100 parts by mass of slag, and 20 parts by mass of pigment are mixed to obtain an earth-based pavement solidifying material. Table 10 shows the composition of the solidification material for earth-based pavement. At this time, 11.1 parts by mass of the solidification material for soil-based pavement is added to 100 parts by mass of the soil. Then, the soil pavement 3 is constructed as in the first embodiment. This soil-based pavement 3 also has the same operation and effect as the second embodiment.
[0062]
[Table 10]
Figure 2004052536
[0063]
(Example 5)
In Example 5, 100 parts by mass of slaked lime, 90 parts by mass of clay, 100 parts by mass of slag, and 20 parts by mass of pigment are mixed to obtain a solidification material for earth-based pavement. Table 11 shows the composition of the solidification material for earth-based pavement. Then, the soil pavement 3 is constructed as in the first embodiment. This soil-based pavement 3 also has the same operation and effect as the second embodiment.
[0064]
[Table 11]
Figure 2004052536
[0065]
In addition, other slag was prepared. Table 12 shows the composition of the slag. The same effect can be obtained by this slag.
[0066]
[Table 12]
Figure 2004052536
[0067]
Also, blast furnace slags with different grain sizes (Nippon Steel Chubu Esment Co., Ltd.) were prepared. Table 13 and FIG. 4 show the particle size distribution of each slag. Although fine slag having an average particle diameter of 30 μm was able to exhibit the same effect as the slag according to Examples 1 to 5, coarse slag having an average particle diameter of 55 μm was reduced in durability due to reduced strength. Undesirable results were obtained.
[0068]
[Table 13]
Figure 2004052536
[0069]
(Test Examples 1 to 10)
As shown in Table 14, at the site where each soil consisting of gravel soil, masa soil, sandy soil or cohesive soil is excavated, while changing the ratio of the solidification material for soil-based pavement, And the soil pavement is constructed in the same manner as in the first embodiment. The conglomerate of Test Example 1 is a commercially available crushed stone ground including a portion under a sieve. The masa soil of Test Examples 2 to 7 is a gravelly sand mixed with fine grains. The crushed stone is single-sized crushed stone No. 6 (5-13). Table 14 also shows the total (mass%) of the silt content and the clay content of the soil (* 1). In addition, slaked lime, clay and slag are the same as those in Example 1, and the ratio of clay (100% by mass) (* 2), the ratio of clay (* 3) and the ratio of slag (* 4) are also shown.
[0070]
[Table 14]
Figure 2004052536
[0071]
Table 15 shows the obtained uniaxial compressive strength (MPa) and evaluation of the soil-based pavement. In the evaluation (1), frost damage occurred in winter and partial delamination occurred on the road surface. In the evaluation, “○” indicates that such peeling did not occur, and excellent durability was exhibited as in Example 1. The maximum dry density of each soil (g / cm 3 ) And the water content (% by mass) at which the maximum dry density is obtained are also shown in Table 15.
[0072]
[Table 15]
Figure 2004052536
[0073]
From Table 15, if the soil-based pavement was constructed under the conditions of Test Examples 1 to 6 and 8, the uniaxial compressive strength on the 7th day after the construction exceeded 2.0 MPa and exhibited sufficient strength as a pedestrian sidewalk. You can see that. In the soil-based pavement constructed under the conditions of Test Example 7, only 5.1 parts by mass of the solidification material for soil-based pavement was contained in 95 parts by mass of soil. It is understood that the compressive strength is low, and the strength cannot be sufficiently exhibited as a pedestrian sidewalk. On the other hand, the soil-based pavement constructed under the conditions of Test Examples 9 and 10 has a large amount of silt or less, indicating poor durability.
[Brief description of the drawings]
FIG. 1 is a schematic sectional view of an earth-based pavement according to Examples 1 to 5.
FIG. 2 is a graph showing the particle size distribution of slaked lime, clay and slag according to Examples 1 to 5.
FIG. 3 is a graph showing a comparison between road surface temperatures of soil-based pavements according to Examples 1 to 5;
FIG. 4 is a graph showing a particle size distribution of slag.
[Explanation of symbols]
1 ... subgrade
2 ... Base
3. Soil-based pavement

Claims (13)

土と混合されて混合土となり、舗装場所に敷きならされた該混合土が転圧及び養生されて土系舗装となる土系舗装用固化材であって、
多孔質材料を含まず、消石灰とスラグとを含むことを特徴とする土系舗装用固化材。
A soil-based pavement solidifying material that is mixed with soil to form a mixed soil, and the compacted soil laid on the pavement site is compacted and cured to form an earth-based pavement,
A solidification material for soil-based pavements, characterized by containing slaked lime and slag without containing a porous material.
粘土を含むことを特徴とする請求項1記載の土系舗装用固化材。The solidified material for an earth-based pavement according to claim 1, further comprising clay. 100質量部の消石灰と、28.6〜100質量部のスラグとを含むことを特徴とする請求項1記載の土系舗装用固化材。The solidified material for earth-based pavement according to claim 1, comprising 100 parts by mass of slaked lime and 28.6 to 100 parts by mass of slag. 100質量部の消石灰と、28.6〜100質量部のスラグと、14.3〜100質量部の粘土とを含むことを特徴とする請求項2記載の土系舗装用固化材。The solidified material for soil-based pavement according to claim 2, comprising 100 parts by mass of slaked lime, 28.6 to 100 parts by mass of slag, and 14.3 to 100 parts by mass of clay. スラグは平均粒径が55μm未満であることを特徴とする請求項1乃至4のいずれか1項記載の土系舗装用固化材。The solidified material for soil-based pavement according to any one of claims 1 to 4, wherein the slag has an average particle size of less than 55 µm. 含水率が5質量%以下であることを特徴とする請求項1乃至5のいずれか1項記載の土系舗装用固化材。The solidified material for an earth-based pavement according to any one of claims 1 to 5, wherein the moisture content is 5% by mass or less. 含水率が2質量%以下であることを特徴とする請求項6記載の土系舗装用固化材。The solidified material for earth-based pavement according to claim 6, wherein the moisture content is 2% by mass or less. 顔料を含むことを特徴とする請求項1乃至7のいずれか1項記載の土系舗装用固化材。The solidification material for an earth-based pavement according to any one of claims 1 to 7, further comprising a pigment. 土は、礫分と砂分とシルト分と粘土分とからなり、最大乾燥密度が1.4g/cm以上であるとともに該最大乾燥密度が得られる含水率が5〜30質量%であり、かつ該シルト分と該粘土分との合計が40質量%以下のものであることを特徴とする請求項1乃至8のいずれか1項記載の土系舗装用固化材。The soil is composed of gravel, sand, silt, and clay, has a maximum dry density of 1.4 g / cm 3 or more, and has a water content of 5 to 30% by mass at which the maximum dry density is obtained, 9. The solidified pavement material according to claim 1, wherein the sum of the silt content and the clay content is 40% by mass or less. 10. 土は、最大乾燥密度が得られる含水率が7〜20質量%であることを特徴とする請求項9記載の土系舗装用固化材。The solidified material for soil-based pavement according to claim 9, wherein the soil has a water content of 7 to 20% by mass at which a maximum dry density is obtained. 土は、シルト分と粘土分との合計が25質量%以下のものであることを特徴とする請求項9又は10記載の土系舗装用固化材。The solidified material for soil-based pavement according to claim 9 or 10, wherein the soil has a total of a silt content and a clay content of 25% by mass or less. 土は、シルト分と粘土分との合計が15質量%以下のものであることを特徴とする請求項11記載の土系舗装用固化材。The solidified material for soil-based pavement according to claim 11, wherein the soil has a total of a silt content and a clay content of 15% by mass or less. 乾燥時の100質量部の混合土に7〜25質量部含まれることを特徴とする請求項1乃至12のいずれか1項記載の土系舗装用固化材。The solidified material for soil-based pavement according to any one of claims 1 to 12, wherein 7 to 25 parts by mass is contained in 100 parts by mass of the mixed soil at the time of drying.
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Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2005162895A (en) * 2003-12-03 2005-06-23 Sumitomo Osaka Cement Co Ltd Material for hardening harmful substance
JP2005344348A (en) * 2004-06-02 2005-12-15 Nippon Road Co Ltd:The Soil-based pavement
JP2007205010A (en) * 2006-02-01 2007-08-16 Inax Corp Mixture and construction method for soil-based pavement, and mixture and construction method for soil-based wall
JP2008239693A (en) * 2007-03-26 2008-10-09 Nippon Steel & Sumikin Stainless Steel Corp Soil based solidifying material and method of paving soil-base solidifying material
JP2009057718A (en) * 2007-08-30 2009-03-19 Masataka Izumi Material for pavement and spraying
JP2010159347A (en) * 2009-01-08 2010-07-22 Tokuyama Corp Soil-solidifying material
JP2014208822A (en) * 2014-05-30 2014-11-06 株式会社シンヨー Composition for manufacturing soil solidified material and soil paving method
CN110397020A (en) * 2019-05-20 2019-11-01 中南大学 It is a kind of that tunnel bottom karst cave treatment method is filled using native horsestone processing tabia

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2005162895A (en) * 2003-12-03 2005-06-23 Sumitomo Osaka Cement Co Ltd Material for hardening harmful substance
JP2005344348A (en) * 2004-06-02 2005-12-15 Nippon Road Co Ltd:The Soil-based pavement
JP2007205010A (en) * 2006-02-01 2007-08-16 Inax Corp Mixture and construction method for soil-based pavement, and mixture and construction method for soil-based wall
JP2008239693A (en) * 2007-03-26 2008-10-09 Nippon Steel & Sumikin Stainless Steel Corp Soil based solidifying material and method of paving soil-base solidifying material
JP2009057718A (en) * 2007-08-30 2009-03-19 Masataka Izumi Material for pavement and spraying
JP2010159347A (en) * 2009-01-08 2010-07-22 Tokuyama Corp Soil-solidifying material
JP2014208822A (en) * 2014-05-30 2014-11-06 株式会社シンヨー Composition for manufacturing soil solidified material and soil paving method
CN110397020A (en) * 2019-05-20 2019-11-01 中南大学 It is a kind of that tunnel bottom karst cave treatment method is filled using native horsestone processing tabia

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