JP5270258B2 - CEMENT-BASED GROUT COMPOSITION AND METHOD FOR PRODUCING PREGROUT PC STEEL USING THE COMPOSITION - Google Patents
CEMENT-BASED GROUT COMPOSITION AND METHOD FOR PRODUCING PREGROUT PC STEEL USING THE COMPOSITION Download PDFInfo
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- 239000011440 grout Substances 0.000 title claims abstract description 77
- 239000000203 mixture Substances 0.000 title claims abstract description 49
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 21
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 76
- 239000010959 steel Substances 0.000 claims abstract description 76
- 229910052918 calcium silicate Inorganic materials 0.000 claims abstract description 23
- 239000003638 chemical reducing agent Substances 0.000 claims abstract description 22
- 239000011398 Portland cement Substances 0.000 claims abstract description 21
- 238000000926 separation method Methods 0.000 claims abstract description 19
- 239000004568 cement Substances 0.000 claims abstract description 14
- 238000000034 method Methods 0.000 claims abstract description 14
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 12
- 239000007787 solid Substances 0.000 claims abstract description 8
- 239000000463 material Substances 0.000 claims description 42
- JHLNERQLKQQLRZ-UHFFFAOYSA-N calcium silicate Chemical compound [Ca+2].[Ca+2].[O-][Si]([O-])([O-])[O-] JHLNERQLKQQLRZ-UHFFFAOYSA-N 0.000 claims description 21
- 235000012241 calcium silicate Nutrition 0.000 claims description 21
- 239000000843 powder Substances 0.000 claims description 10
- LYCAIKOWRPUZTN-UHFFFAOYSA-N Ethylene glycol Chemical compound OCCO LYCAIKOWRPUZTN-UHFFFAOYSA-N 0.000 claims description 4
- 235000019738 Limestone Nutrition 0.000 claims description 3
- 229920003086 cellulose ether Polymers 0.000 claims description 3
- 239000011248 coating agent Substances 0.000 claims description 3
- 238000000576 coating method Methods 0.000 claims description 3
- 239000006028 limestone Substances 0.000 claims description 3
- 229910021487 silica fume Inorganic materials 0.000 claims description 3
- 229920002472 Starch Polymers 0.000 claims description 2
- -1 biopolysaccharide Substances 0.000 claims description 2
- 239000010881 fly ash Substances 0.000 claims description 2
- WGCNASOHLSPBMP-UHFFFAOYSA-N hydroxyacetaldehyde Natural products OCC=O WGCNASOHLSPBMP-UHFFFAOYSA-N 0.000 claims description 2
- 229920000058 polyacrylate Polymers 0.000 claims description 2
- 229920000642 polymer Polymers 0.000 claims description 2
- 239000002893 slag Substances 0.000 claims description 2
- 239000008107 starch Substances 0.000 claims description 2
- 235000019698 starch Nutrition 0.000 claims description 2
- 239000000835 fiber Substances 0.000 claims 1
- 230000000740 bleeding effect Effects 0.000 abstract description 8
- 230000007613 environmental effect Effects 0.000 abstract description 4
- 230000002349 favourable effect Effects 0.000 abstract 1
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- 238000002156 mixing Methods 0.000 description 6
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- 230000000694 effects Effects 0.000 description 5
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- 239000000047 product Substances 0.000 description 4
- 125000002947 alkylene group Chemical group 0.000 description 3
- 239000002270 dispersing agent Substances 0.000 description 3
- 150000001298 alcohols Chemical class 0.000 description 2
- 230000005540 biological transmission Effects 0.000 description 2
- 239000003795 chemical substances by application Substances 0.000 description 2
- 239000013065 commercial product Substances 0.000 description 2
- 238000005189 flocculation Methods 0.000 description 2
- 230000016615 flocculation Effects 0.000 description 2
- 238000006703 hydration reaction Methods 0.000 description 2
- 239000011513 prestressed concrete Substances 0.000 description 2
- 239000011443 resin grout Substances 0.000 description 2
- 235000008733 Citrus aurantifolia Nutrition 0.000 description 1
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 1
- BWGVNKXGVNDBDI-UHFFFAOYSA-N Fibrin monomer Chemical class CNC(=O)CNC(=O)CN BWGVNKXGVNDBDI-UHFFFAOYSA-N 0.000 description 1
- 229920001732 Lignosulfonate Polymers 0.000 description 1
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 1
- 235000011941 Tilia x europaea Nutrition 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 150000001414 amino alcohols Chemical class 0.000 description 1
- 239000002518 antifoaming agent Substances 0.000 description 1
- 229920002678 cellulose Polymers 0.000 description 1
- 239000001913 cellulose Substances 0.000 description 1
- 238000009833 condensation Methods 0.000 description 1
- 230000005494 condensation Effects 0.000 description 1
- 229920001577 copolymer Polymers 0.000 description 1
- 230000003111 delayed effect Effects 0.000 description 1
- MTHSVFCYNBDYFN-UHFFFAOYSA-N diethylene glycol Chemical compound OCCOCCO MTHSVFCYNBDYFN-UHFFFAOYSA-N 0.000 description 1
- 239000000246 fibrin derivative Substances 0.000 description 1
- 238000009472 formulation Methods 0.000 description 1
- 238000009415 formwork Methods 0.000 description 1
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- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 1
- 239000004571 lime Substances 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 229920000570 polyether Polymers 0.000 description 1
- 229920005862 polyol Polymers 0.000 description 1
- 150000003077 polyols Chemical class 0.000 description 1
- 230000003449 preventive effect Effects 0.000 description 1
- 230000000979 retarding effect Effects 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
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- 239000008399 tap water Substances 0.000 description 1
- 235000020679 tap water Nutrition 0.000 description 1
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Abstract
Description
本発明は、土木、建築分野で使用されるプレストレストコンクリート構造物を製造する際に用いられるセメント系グラウト組成物及び該組成物を用いたプレグラウトPC鋼材の製造方法に関する。 The present invention relates to a cement-type grout composition used when producing a prestressed concrete structure used in the field of civil engineering and construction, and a method for producing a pre-grout PC steel material using the composition.
プレストレストコンクリート構造物の製造方法としては、コンクリートの打ち込み・養生後に、コンクリートに予め形成されたダクトにPC鋼材を挿入、緊張、定着し、ダクトにセメント系グラウトを注入し、PC鋼材とダクトの間を充填するポストテンション工法が知られている(特許文献１)。
また、建設現場で型枠内に透明シースを配置して、シースにPC鋼材を挿入し、硬化遅延性を有するセメント系グラウトを注入し、コンクリートを打ち込み、該コンクリートが緊張に耐える強度が発現した後に、PC鋼材を緊張、定着するプレグラウチング工法も知られている(特許文献２及び３)。
更に、工場の生産ラインで連続的にPC鋼材の外周に硬化遅延性を有するグラウトを塗布し、さらに、グラウトの外周にプラスチック製のシースを被覆したプレグラウトPC鋼材を製造し、これを現場で組み立てて、PC鋼材を緊張するプレグラウト工法も知られている。
これらの工法において、PC鋼材による緊張は、コンクリートへの均等な応力伝達を達成するために、PC鋼材の端部や中央部等のいずれにおいても均等な力で緊張されることが望ましい。
しかし、上記プレグラウチング工法やプレグラウト工法では、PC鋼材を緊張する際に、シースとPC鋼材の間にセメント系グラウトが存在する場合、PC鋼材とシースとの摩擦係数が、PC鋼材を緊張、定着した後に、ダクトにセメント系グラウトを注入するような上述のポストテンション工法に比べて大きくなる可能性が高い。
上記プレグラウチング工法における、現場でのセメント系グラウトの注入は、その作業性を良好にするために、PC鋼材とシース内面との間隙がある程度広げられている。一方、プレグラウト工法では、工場での生産性や、工場から現場までの運搬性等を良好にするために、該間隙がプレグラウチング工法の場合に比して狭くなっている。
上記PC鋼材とシース内面との間隙がある程度広げられている場合には、例えば、特許文献２及び３に記載されるような、高ビーライト系ポルトランドセメントと、無機質混和材と、分離低減剤と、水と、必要により分散剤等を含むセメント系グラウトを用いた場合であっても、上記PC鋼材とシースとの摩擦係数への影響はほとんどない。
一方、同様なセメント系グラウトをプレグラウト工法における、上記間隙の狭い場合に適用すると、上記摩擦係数に影響を及ぼすおそれが高くなり、PC鋼材による緊張において、コンクリートへの均等な応力伝達が困難になるおそれがある。特に、シースが湾曲している場合はその傾向が更に高くなる。そこで、プレグラウト工法においては、摩擦係数への影響が無い樹脂系グラウトの使用が提案されている。しかし、該樹脂系グラウトは、環境面や作業時の安全性への問題が懸念されている。
The prestressed concrete structure is manufactured by inserting PC steel into a duct formed in concrete after concrete placement and curing, injecting and fixing, and injecting cement-type grout into the duct between the PC steel and the duct. There is known a post-tensioning method for filling the material (Patent Document 1).
In addition, a transparent sheath was placed in the formwork at the construction site, PC steel was inserted into the sheath, cement-type grout having a setting delay was injected, concrete was poured in, and the concrete developed strength to withstand tension. A pre-grouting method for tensioning and fixing PC steel later is also known (Patent Documents 2 and 3).
Furthermore, grout having a retarding property is applied continuously to the outer periphery of the PC steel material at the factory production line, and further, a pre-grout PC steel material having a plastic sheath coated on the outer periphery of the grout is manufactured and assembled on site. A pre-grouting method is also known, which tensions PC steel.
In these construction methods, it is desirable that the tension due to the PC steel is tensioned with an equal force at either the end or the center of the PC steel in order to achieve uniform stress transmission to the concrete.
However, in the above pre-grouting method and pre-grouting method, when a PC steel material is tensioned, if a cement-type grout exists between the sheath and the PC steel material, the friction coefficient between the PC steel material and the sheath tensions and fixes the PC steel material. After that, there is a high possibility that it becomes larger than the above-described post tension method in which cement grout is injected into the duct.
In the pre-grouting method, in-situ cement grout is injected with a certain gap between the PC steel and the sheath inner surface in order to improve the workability. On the other hand, in the pre-grouting method, the gap is narrower than in the case of the pre-grouting method in order to improve the productivity in the factory and the transportability from the factory to the site.
When the gap between the PC steel material and the sheath inner surface is widened to some extent, for example, as described in Patent Documents 2 and 3, a high belite-based Portland cement, an inorganic admixture, a separation reducing agent, Even if a cement-type grout containing water and, if necessary, a dispersant is used, there is almost no influence on the friction coefficient between the PC steel material and the sheath.
On the other hand, if a similar cement grout is applied in the pre-grouting method when the gap is narrow, there is a high risk of affecting the friction coefficient, and it becomes difficult to transmit uniform stress to concrete under tension caused by PC steel. There is a fear. In particular, when the sheath is curved, the tendency is further increased. Therefore, in the pre-grouting method, the use of a resin grout that does not affect the friction coefficient has been proposed. However, the resin grout is concerned about environmental problems and safety issues during work.
ところで、工場で生産されるプレグラウトPC鋼材を用いる場合には、現場で行うプレグラウチング工法に比べ、工場製造から、運搬、設置、コンクリートの打ち込み及び養生、プレグラウトPC鋼材の緊張まで時間を要する。そこで、プレグラウトPC鋼材に使用されるセメント系グラウトの凝結の始発時間を２ヶ月間以上に延長する必要がある。特に、夏期等の気温が高い環境下においては、上記特許文献２及び３に記載されたグラウトであっても、その硬化遅延性が必ずしも十分と言えない場合がある。
本発明の課題は、夏期等の環境温度が高い場合であっても、凝結時間が長く、ブリーディングが有効に抑制され、グラウトに一般に要求される種々の特性を兼ね備え、しかも、PC鋼材の緊張時における該PC鋼材とシースとの摩擦係数を、シース内表面とPC鋼材との間隙が狭い場合であっても低減することができるセメント系グラウト組成物を提供することにある。
本発明の別の課題は、PC鋼材の緊張時における該PC鋼材とシースとの摩擦係数が低減され、コンクリートへの均等な応力伝達を可能にし、且つ夏期等の環境温度が高い場合であっても、凝結時間が長く、緊張可能時間が長いプレグラウトPC鋼材の製造方法を提供することにある。
The problem of the present invention is that even when the environmental temperature is high, such as in summer, the setting time is long, bleeding is effectively suppressed, and has various characteristics generally required for grout, and when the PC steel is in tension An object of the present invention is to provide a cement-type grout composition that can reduce the coefficient of friction between the PC steel material and the sheath even when the gap between the inner surface of the sheath and the PC steel material is narrow.
Another problem of the present invention is a case where the friction coefficient between the PC steel material and the sheath is reduced during the tension of the PC steel material, enables uniform stress transmission to the concrete, and has a high environmental temperature such as in summer. Another object is to provide a method for producing pre-grout PC steel with a long setting time and a long possible tension time.
本発明者らは、上記課題を解決するために鋭意検討した結果、従来の認識では達成し得ないと思われていた、特定のセメント、凝結遅延剤、分離低減剤及び水のみを用い、無機質混和材を用いない場合であっても、これらの含有量を特定割合とし、粘度を調整することによって、温度が高い環境においても、グラウトに要求される一般性能を維持しつつ、凝結時間を従来に比べて延長させることができ、さらに、PC鋼材とシースとの緊張時の摩擦係数を低減させるという上記課題が解決しうることを見出し、本発明を完成した。 As a result of intensive studies to solve the above problems, the present inventors have used only a specific cement, a setting retarder, a separation reducing agent, and water, which have been thought to be unattainable by conventional recognition, and are inorganic. Even when admixtures are not used, by adjusting the viscosity to a specific ratio and adjusting the viscosity, the setting time can be reduced while maintaining the general performance required for grout even in high temperature environments. It was found that the above problem of reducing the friction coefficient during tension between the PC steel material and the sheath can be solved, and the present invention has been completed.
本発明によれば、ビーライトを３０質量％以上含有する高ビーライト系ポルトランドセメントと、凝結遅延剤と、分離低減剤と、水とを含み、フライアッシュ、高炉スラグ微粉末、シリカフュームおよび石灰石微粉末よりなる群から選択される一つ以上からなる無機微粉末を含まない組成物であって、前記高ビーライト系ポルトランドセメント１００質量部に対して、凝結遅延剤の含有割合が固形分換算で１．０５〜２．０質量部であり、分離低減剤の含有割合が固形分換算で０．５５〜０．９５質量部であり、水／前記高ビーライト系ポルトランドセメント比が４０〜４５％であり、組成物のJIS R 5201に準拠したフロー値が１９０〜２４０ｍｍであることを特徴とするセメント系グラウト組成物(以下、本発明のグラウト組成物又は本発明の組成物と略すことがある)が提供される。
また本発明によれば、PC鋼材の外周に、本発明のグラウト組成物を塗布する工程と、塗布したセメント系グラウト組成物の外周に、プラスチック製シースを被覆する工程とを含むプレグラウトPC鋼材の製造方法が提供される。
According to the present invention, fly ash, fine powder of blast furnace slag, silica fume and fine limestone are contained, including high belite-based Portland cement containing 30% by mass or more of belite, a setting retarder, a separation reducing agent, and water. It is a composition not containing one or more inorganic fine powders selected from the group consisting of powders, and the content of the setting retarder is calculated in terms of solid content with respect to 100 parts by mass of the high belite system Portland cement. 1.05 to 2.0 parts by mass, the content of the separation reducing agent is 0.55 to 0.95 parts by mass in terms of solid content, and the water / high belite system Portland cement ratio is 40 to 45%. The cement-type grout composition (hereinafter referred to as the grout composition of the present invention or the present invention) having a flow value in accordance with JIS R 5201 of 190 to 240 mm. May be abbreviated as formed product) are provided.
Further, according to the present invention, there is provided a pre-grout PC steel material including a step of applying the grout composition of the present invention to the outer periphery of the PC steel material, and a step of covering the outer periphery of the applied cementitious grout composition with a plastic sheath. A manufacturing method is provided.
本発明のグラウト組成物は、特定のセメント、凝結遅延剤、分離低減剤及び水を含み、これらの含有量を特定割合とし、且つ組成物の粘度を制御しているので、従来提案されている無機質混和材を配合しなくても、グラウトとしての適正な粘度を維持し、ブリーディングを有効に抑制し、しかも、夏期等の温度が高い環境であっても、始発時間が製造から２ヶ月以上という十分な凝結遅延効果が得られる。また、無機質混和材を実質的に含有しないことにより、PC構造物製造時におけるPC鋼材の緊張の際の該PC鋼材とシースとの摩擦係数を小さくすることができる。例えば、緊張時におけるPC鋼材とプラスチック製シースとの摩擦において、角度変化1ラジアンの摩擦係数を０．３０以下に、長さ１ｍあたりの摩擦係数を０．００４以下にすることができる。
従って、本発明のグラウト組成物は、プレグラウトPC鋼材の製造に有用である。
本発明のプレグラウトPC鋼材の製造方法は、本発明のグラウト組成物を利用するので、緊張可能日数による制約が少なく、また、PC鋼材とシースとの緊張時の摩擦係数が小さいので、コンクリート構造物に均等なプレストレスを付与することができ、且つ施工後の緊張可能時間が長いプレグラウトPC鋼材を、簡便に提供することができる。
The grout composition of the present invention has been conventionally proposed because it contains a specific cement, a setting retarder, a separation reducing agent, and water, the content of which is a specific ratio, and the viscosity of the composition is controlled. Even without blending inorganic admixtures, it maintains the proper viscosity as a grout, effectively suppresses bleeding, and the initial time is 2 months or more even in high temperature environments such as summer Sufficient setting delay effect can be obtained. Further, by containing substantially no inorganic admixture, it is possible to reduce the coefficient of friction between the PC steel material and the sheath when the PC steel material is tensioned during the manufacture of the PC structure. For example, in the friction between a PC steel material and a plastic sheath during tension, the friction coefficient with an angle change of 1 radian can be set to 0.30 or less, and the friction coefficient per 1 m length can be set to 0.004 or less.
Therefore, the grout composition of the present invention is useful for the production of pre-grout PC steel.
The method for producing the pre-grout PC steel material of the present invention uses the grout composition of the present invention, so that there are few restrictions due to the number of days that can be tensioned, and the friction coefficient during tension between the PC steel material and the sheath is small. It is possible to easily provide a pre-grout PC steel material that can be applied with a uniform pre-stress and has a long tensionable time after construction.
以下、本発明を更に詳細に説明する。
本発明の組成物は、特定の高ビーライト系ポルトランドセメント、凝結遅延剤、分離低減剤及び水を特定割合で含む。
Hereinafter, the present invention will be described in more detail.
The composition of the present invention contains specific high belite-based Portland cement, setting retarder, separation reducing agent and water in specific proportions.
高ビーライト系ポルトランドセメントとしては、低熱ポルトランドセメント、もしくは低熱ポルトランドセメントと普通ポルトランドセメントとの混合物が挙げられる。
高ビーライト系ポルトランドセメントにおいて、ビーライトの含有割合は、３０質量％以上、好ましくは４０質量％以上である。ビーライトの含有割合を高くすることにより、グラウトの凝結時間が遅延する傾向にある。しかし、遅延しすぎを抑制するために、ビーライトの含有割合の上限は、通常７０質量％程度が好ましい。また、高ビーライト系ポルトランドセメントの比表面積は、水和反応及び自己収縮量を抑制するために、４０００ｃｍ2／ｇ以下が好ましい。
Examples of the high belite light Portland cement include a low heat Portland cement or a mixture of a low heat Portland cement and a normal Portland cement.
In the high belite system Portland cement, the content ratio of belite is 30% by mass or more, preferably 40% by mass or more. By increasing the content ratio of belite, the setting time of grout tends to be delayed. However, in order to suppress an excessive delay, the upper limit of the content ratio of belite is usually preferably about 70% by mass. Further, the specific surface area of the high belite type Portland cement is preferably 4000 cm 2 / g or less in order to suppress the hydration reaction and the amount of self-shrinkage.
凝結遅延剤としては、例えば、リグニンスルホン酸塩、オキシカルボン酸塩、ポリオール有機誘導体又はこれら２種以上の混合物が挙げられ、特に、オキシカルボン酸塩を含むことが好ましい。
本発明の組成物において、凝結遅延剤の含有割合は、ビーライト系ポルトランドセメント１００質量部に対して、固形分換算で１．０５〜２．０質量部、好ましくは１．１〜１．５質量部である。この割合が１．０５質量部未満では、十分な凝結遅延効果が得られないおそれがある。また、２．０質量部を超えると、セメントの水和を著しく阻害し、グラウトが硬化しないおそれがある。
Examples of the setting retarder include lignin sulfonates, oxycarboxylates, polyol organic derivatives or a mixture of two or more of these, and it is particularly preferable to include an oxycarboxylate.
In the composition of the present invention, the content of the setting retarder is 1.05 to 2.0 parts by mass, preferably 1.1 to 1.5, in terms of solid content with respect to 100 parts by mass of belite-based Portland cement. Part by mass. If this ratio is less than 1.05 parts by mass, a sufficient setting delay effect may not be obtained. Moreover, when it exceeds 2.0 mass parts, the hydration of a cement will be inhibited remarkably and there is a possibility that grout may not harden.
分離低減剤は、コンクリートの硬化熱により加熱された環境下、例えば９５℃の高温下においても分離低減効果を維持しうるものの使用が好ましい。例えば、セルロースエーテル系、アクリルポリマー系、グリコール系、バイオポリサッカライド系、繊維素誘導体ポリマー系若しくは澱粉系の粉末系分離低減剤又はこれら２種以上の混合物が挙げられ、特に、セルロースエーテル系の分離低減剤を含むことが好ましい。分離低減剤の形態は、運搬、貯蔵およびグラウトの製造の点から粉末であることが好ましい。
本発明の組成物において、分離低減剤の含有割合は、高ビーライト系ポルトランドセメント１００質量部に対して、固形分換算で０．５５〜０．９５質量部、好ましくは０．５５〜０．８０質量部である。この割合が０．５５質量部未満では、グラウト組成物の粘性が低すぎて、８０℃の高温下においてブリーディングが発生するおそれがあり、さらに、プレグラウトPC鋼材の製造時において、PC鋼材外周への塗布が困難になるおそれがある。また、０．９５質量部を超えると、グラウト組成物の粘性が高すぎて、練り混ぜが困難となり、更には、プレグラウトPC鋼材の製造時において、PC鋼材外周への塗布が困難になるおそれがある。
It is preferable to use a separation reducing agent that can maintain the separation reduction effect even in an environment heated by the heat of hardening of the concrete, for example, at a high temperature of 95 ° C. Examples include cellulose ether-based, acrylic polymer-based, glycol-based, biopolysaccharide-based, fibrin derivative polymer-based or starch-based powder-based separation reducing agents, or a mixture of two or more of these, in particular cellulose ether-based separation. It is preferable to include a reducing agent. The form of the separation reducing agent is preferably a powder from the viewpoint of transportation, storage and production of grout.
In the composition of the present invention, the content of the separation reducing agent is 0.55 to 0.95 parts by mass, preferably 0.55 to 0.005, in terms of solid content with respect to 100 parts by mass of high belite system Portland cement. 80 parts by mass. If this proportion is less than 0.55 parts by mass, the viscosity of the grout composition is too low, and bleeding may occur at a high temperature of 80 ° C. Further, during the production of pregrout PC steel, Application may be difficult. Further, if it exceeds 0.95 parts by mass, the viscosity of the grout composition is too high and mixing becomes difficult, and furthermore, it may be difficult to apply to the outer periphery of the PC steel during the production of the pre-grout PC steel. is there.
本発明の組成物において、水／高ビーライト系ポルトランドセメント比は、４０〜４５％、好ましくは４１〜４４％である。この比が４０％未満では、PC鋼材緊張時におけるPC鋼材とシースとの摩擦係数が大きくなり、コンクリートに与えるPC鋼材の有効応力を低減させるおそれがある。また、４５％を超えると、グラウト組成物が硬化した際の圧縮強度が低下し、PC鋼材とコンクリートとの一体化を確保できないおそれがある。 In the composition of the present invention, the water / high belite system Portland cement ratio is 40 to 45%, preferably 41 to 44%. If this ratio is less than 40%, the coefficient of friction between the PC steel material and the sheath increases when the PC steel material is in tension, which may reduce the effective stress of the PC steel material applied to the concrete. Moreover, when it exceeds 45%, the compressive strength at the time of hardening of a grout composition will fall, and there exists a possibility that integration with PC steel materials and concrete cannot be ensured.
本発明のグラウト組成物は、上記成分以外に、本発明の所望の効果を損なわない範囲で、他の成分を含有させることもできる。
他の成分としては、例えば、収縮低減剤が挙げられる。
収縮低減剤としては、例えば、低級アルコールのアルキレンオキシド付加物系、ポリエーテル系、アルコール系、低分子量アルキレンオキシド共重合体系若しくはグリコールエーテル・アミノアルコール誘導体系のもの又はこれら２種以上の混合物が挙げられる。
本発明の組成物には、更に、膨張剤、防錆剤及び消泡剤等の各種成分を必要に応じ含有させることもできる。
上記他の成分の配合割合は、その目的に応じて適宜選択することができる。
The grout composition of the present invention can contain other components in addition to the above components as long as the desired effects of the present invention are not impaired.
Examples of other components include a shrinkage reducing agent.
Examples of the shrinkage reducing agent include alkylene oxide adducts of lower alcohols, polyethers, alcohols, low molecular weight alkylene oxide copolymers or glycol ether / amino alcohol derivatives, or mixtures of two or more of these. It is done.
The composition of the present invention may further contain various components such as a swelling agent, a rust preventive agent and an antifoaming agent as necessary.
The blending ratio of the other components can be appropriately selected according to the purpose.
本発明の組成物の製造方法は、特に限定されず、工場又は施工現場で、プレミックス又は水を含んだ組成物となるよう、各成分を配合し、混合することにより調製することができる。 The manufacturing method of the composition of this invention is not specifically limited, It can prepare by mix | blending and mixing each component so that it may become a composition containing a premix or water in a factory or a construction site.
本発明のグラウト組成物及びその硬化物は、通常、以下の物性を有する：
(1)図１に示す夏期と通常期の温度履歴を受けた後にグラウトの凝結試験(JIS R 5201-97に準拠)における始発時間が、夏期で２ヶ月間以上、通常期で３ヶ月間以上、
(2)グラウトのブリーディング率(JSCE-F532-1999に準拠、試験温度が８４℃）：０％、
(3)グラウトの流動性（JIS R 5201に準拠）：フロー値１９０〜２４０ｍｍ、
(4)グラウトの凝結終結時膨張率(JSCE-F532-1999に準拠)：−０．５〜＋０．５％、
(5)圧縮強度(JSCE-G531-1999に準拠)：凝結終結後５６日で３０Ｎ／ｍｍ2以上、
(6)緊張時PC鋼より線とシースとの摩擦係数（通常期温度履歴を受けた後、プレグラウトPC鋼材製造後６０日）：角度変化1ラジアンの摩擦係数μは０．３０以下、長さ１ｍあたりの摩擦係数λは０．００４以下。
特に、本発明の組成物が、(3)のグラウトの流動性を充足しない場合には、プレグラウトPC鋼材製造時において、PC鋼材に本発明の組成物を塗布することが困難になり、所望の効果が得られないおそれがある。
The grout composition of the present invention and its cured product usually have the following physical properties:
(1) After receiving the summer and normal temperature history shown in Fig. 1, the initial time in the grout condensation test (conforming to JIS R 5201-97) is 2 months or more in summer and 3 months or more in normal period ,
(2) Grouting bleeding rate (according to JSCE-F532-1999, test temperature 84 ° C): 0%
(3) Flowability of grout (conforming to JIS R 5201): Flow value 190-240mm,
(4) Expansion rate at the end of setting of grout (according to JSCE-F532-1999): -0.5 to + 0.5%,
(5) Compressive strength (according to JSCE-G531-1999): More than 30 N /
(6) Friction coefficient between wire and sheath from PC steel during tension (60 days after manufacturing pre-grouting PC steel after receiving normal temperature history): Friction coefficient μ of angle change 1 radians is less than 0.30, length The friction coefficient λ per meter is 0.004 or less.
In particular, when the composition of the present invention does not satisfy the flowability of the grout of (3), it becomes difficult to apply the composition of the present invention to the PC steel during the production of the pre-grout PC steel. The effect may not be obtained.
本発明のプレグラウトPC鋼材の製造方法は、PC鋼材の外周に、本発明のグラウト組成物を塗布する工程と、塗布したセメント系グラウト組成物の外周に、プラスチック製シースを被覆する工程とを含む。
PC鋼材は、通常のPC鋼より線を用いることができる。プラスチック製シースも、公知のものを用いることができる。
プレグラウトPC鋼材を工場で製造する場合は、その生産性や現場への運搬性を良好なものとするために、プラスチック製シースの内径と、PC鋼材の直径との差が、１６ｍｍ以下、好ましくは１５〜１０ｍｍとすることが好ましい。このような狭い間隙であっても、本発明の組成物は、PC鋼材とシーストの摩擦係数を低減することができ、コンクリートに均等なプレストレスを付与することができる。
The method for producing the pre-grout PC steel material of the present invention includes a step of applying the grout composition of the present invention to the outer periphery of the PC steel material, and a step of coating a plastic sheath on the outer periphery of the applied cementitious grout composition. .
As the PC steel material, a normal PC steel wire can be used. A well-known plastic sheath can also be used.
When producing pre-grout PC steel at the factory, the difference between the inner diameter of the plastic sheath and the diameter of the PC steel is 16 mm or less, preferably in order to improve the productivity and transportability to the site. It is preferable to set it as 15-10 mm. Even in such a narrow gap, the composition of the present invention can reduce the friction coefficient between the PC steel material and the seast, and can impart an equal prestress to the concrete.
以下に本発明を実施例により詳細に説明するが、本発明はこれらに限定されない。
表１に示す各配合のセメント系グラウトをグラウトミキサ（MG100、1000回転/分）で混練し、グラウトを製造した。尚、表１中の各成分は以下のとおりである。
Ｉ．セメント
低熱ポルトランドセメント（略号：LC)：ビーライト含有率＝５５％、密度＝３．２４、比表面積＝３３１０cm2/g（住友大阪セメント(株)製）
普通ポルトランドセメント（略号：NC)：ビーライト含有率＝２４％、密度＝３．１５、比表面積＝３２８０cm2/g（太平洋セメント(株)製）
II．粉末状セメント分散剤
粉末状ポリカルボン酸系セメント分散剤（PC）：市販品（商品名：コアフローNF-100、太平洋マテリアル(株)製）
III．無機質混和材
シリカフューム（略号：SF）：密度＝２．２、比表面積＝２００，０００ｃｍ2／ｇ、市販品（商品名：マイクロシリカ９４０、エルケム社製）
石灰石微粉末（略号：LSP）：密度＝２．６７、比表面積＝３８４０ｃｍ2／ｇ、市販品（商品名：工業用タンカル、吉澤石灰工業(株)製）
IV．粉末状セメント凝結遅延剤
オキシカルボン酸塩系セメント凝結遅延剤（略号：PR）：市販品
Ｖ．粉末状分離低減剤
セルロース系分離低減剤（略号：V）：（商品名：、マーポローズ、松本油脂製薬(株)製）
VI．有機系収縮低減剤
粉末状有機系収縮低減剤（略号：TG）：低級アルコールのアルキレンオキシド付加物系（太平洋セメント(株)製）
VII．練り混ぜ水
上水道水
EXAMPLES The present invention will be described in detail below with reference to examples, but the present invention is not limited thereto.
Cement-type grouts of each formulation shown in Table 1 were kneaded with a grout mixer (MG100, 1000 rpm) to produce grout. In addition, each component in Table 1 is as follows.
I. Cement Low heat Portland cement (abbreviation: LC): Belite content = 55%, density = 3.24, specific surface area = 3310 cm 2 / g (manufactured by Sumitomo Osaka Cement Co., Ltd.)
Ordinary Portland cement (abbreviation: NC): Belite content = 24%, density = 3.15, specific surface area = 3280 cm 2 / g (manufactured by Taiheiyo Cement Co., Ltd.)
II. Powdered cement dispersant Powdered polycarboxylic acid cement dispersant (PC): Commercial product (trade name: Coreflow NF-100, manufactured by Taiheiyo Materials Co., Ltd.)
III. Inorganic admixture Silica fume (abbreviation: SF): density = 2.2, specific surface area = 200,000 cm 2 / g, commercially available product (trade name: microsilica 940, manufactured by Elchem)
Limestone fine powder (abbreviation: LSP): density = 2.67, specific surface area = 3840 cm 2 / g, commercially available product (trade name: industrial tankal, manufactured by Yoshizawa Lime Industry Co., Ltd.)
IV. Powdered cement setting retarder Oxycarboxylate-based cement setting retarder (abbreviation: PR): commercial product Powder-type separation reducing agent Cellulose-based separation reducing agent (abbreviation: V): (trade name: Marporose, manufactured by Matsumoto Yushi Seiyaku Co., Ltd.)
VI. Organic shrinkage reducing agent Powdery organic shrinkage reducing agent (abbreviation: TG): alkylene oxide adduct system of lower alcohol (manufactured by Taiheiyo Cement Co., Ltd.)
VII. Mixing water Tap water
得られた各グラウトについて、図１に示す、通常期と夏期を模擬した養生パターンでグラウトを養生し、下記の試験方法に準拠し、流動性試験、ブリーディング測定、凝結試験および圧縮強度試験を行った。結果を表２に示す。
(1)グラウトの流動性（その２）：JIS R 5201に準拠し、グラウト製造直後にフロー値を測定した。
(2)グラウトのブリーディング率：JSCE-F532-1999に準拠し、試験温度８４℃でのブリーディング率を測定した。
(3)グラウト凝結の始発時間：JIS R 5201-97に準拠し、図１に示す通常期と夏期の温度履歴をそれぞれ与え、それぞれのグラウトの凝結の始発時間を測定した。
(4)グラウトの凝結終結時の膨張率：JSCE-F532-1999に準拠し、グラウトの凝結終結時膨張率を測定した。
(5)圧縮強度：JSCE-G531-1999に準拠し、凝結終結後５６日の圧縮強度を測定した。
(6)緊張時PC鋼より線とシースとの摩擦係数：得られたグラウトを、直径28.6ｍｍ、長さ10ｍのPC鋼より線の周囲に、厚さ約6ｍｍとなるように塗布した。次いで、内径40ｍｍのプラスチック製シースにより覆い、その周りにコンクリートを打設してプレグラウトPC鋼材を製造した。通常期養生パターンで養生し、プレグラウトPC鋼材製造後６０日に、プレグラウトPC鋼材を緊張し、その角度変化１ラジアンの摩擦係数μと長さ１ｍあたりの摩擦係数λをそれぞれ測定した。
About each obtained grout, the grout is cured with the curing pattern simulating the normal period and the summer period shown in FIG. 1, and the fluidity test, bleeding measurement, setting test and compressive strength test are performed according to the following test methods. It was. The results are shown in Table 2.
(1) Fluidity of grout (part 2): According to JIS R 5201, the flow value was measured immediately after the production of grout.
(2) Grouting bleeding rate: The bleeding rate at a test temperature of 84 ° C. was measured according to JSCE-F532-1999.
(3) Initial time of flocculation: Based on JIS R 5201-97, the temperature history of the normal period and the summer period shown in FIG. 1 was given, respectively, and the initial time of flocculation was measured.
(4) Expansion rate at the end of the setting of the grout: The expansion rate at the end of the setting of the grout was measured according to JSCE-F532-1999.
(5) Compressive strength: Based on JSCE-G531-1999, the compressive strength was measured 56 days after completion of the setting.
(6) Coefficient of friction between PC steel wire and sheath when tensioned: The obtained grout was applied around a PC steel wire having a diameter of 28.6 mm and a length of 10 m so as to have a thickness of about 6 mm. Next, it was covered with a plastic sheath having an inner diameter of 40 mm, and concrete was cast around it to produce a pre-grout PC steel material. The pre-grout PC steel was cured with a normal-period curing pattern, and 60 days after the pre-grout PC steel was manufactured, the pre-grout PC steel was tensioned, and the friction coefficient μ of the angle change of 1 radian and the friction coefficient λ per 1 m of length were measured.
尚、比較例２、比較例３及び比較例８のグラウトは、フロー値が高すぎるため、ＰＣ鋼材に塗布する際に、グラウトがＰＣ鋼材から垂れてプレグラウトPC鋼材を製造することができなかった。また、比較例９のグラウトは、ＰＣ鋼材に塗布するに必要な流動性、即ち、フロー値が低すぎるため、ＰＣ鋼材に塗布する際に、グラウトが硬すぎて、ＰＣ鋼材の外周に均等に成形できず、プレグラウトPC鋼材を製造できなかった。 In addition, since the grout of the comparative example 2, the comparative example 3, and the comparative example 8 has too high flow value, when apply | coating to PC steel material, the grout drooped from PC steel material and the pre-grouting PC steel material could not be manufactured. . Further, the grout of Comparative Example 9 has a fluidity necessary for application to the PC steel material, that is, the flow value is too low. Therefore, when applied to the PC steel material, the grout is too hard and evenly on the outer periphery of the PC steel material. It was not possible to form and pre-grout PC steel could not be manufactured.
Claims (4)
前記高ビーライト系ポルトランドセメント１００質量部に対して、凝結遅延剤の含有割合が固形分換算で１．０５〜２．０質量部であり、分離低減剤の含有割合が固形分換算で０．５５〜０．９５質量部であり、水／前記ビーライト系ポルトランドセメント比が４０〜４５％であり、組成物のJIS R 5201に準拠したフロー値が１９０〜２４０ｍｍであることを特徴とするセメント系グラウト組成物。 A high belite-based Portland cement containing 30% by weight or more of belite, a setting retarder, a separation reducing agent, and water, and selected from the group consisting of fly ash, blast furnace slag fine powder, silica fume, and limestone fine powder A composition comprising no more than one inorganic fine powder,
The content rate of the setting retarder is 1.05 to 2.0 parts by mass in terms of solid content with respect to 100 parts by mass of the high belite type Portland cement, and the content rate of the separation reducing agent is 0. 0 in terms of solid content. Cement characterized in that it is 55 to 0.95 parts by mass, the water / belite-based Portland cement ratio is 40 to 45%, and the flow value according to JIS R 5201 of the composition is 190 to 240 mm. Grout composition.
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