JP6256053B2 - Surface finishing method for ultra high strength fiber reinforced concrete - Google Patents

Surface finishing method for ultra high strength fiber reinforced concrete Download PDF

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JP6256053B2
JP6256053B2 JP2014016291A JP2014016291A JP6256053B2 JP 6256053 B2 JP6256053 B2 JP 6256053B2 JP 2014016291 A JP2014016291 A JP 2014016291A JP 2014016291 A JP2014016291 A JP 2014016291A JP 6256053 B2 JP6256053 B2 JP 6256053B2
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浩司 玉滝
浩司 玉滝
由隆 藤野
由隆 藤野
浩一郎 吉田
浩一郎 吉田
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Ube Corp
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Description

本発明は、超高強度繊維補強コンクリートの表面仕上げ方法に関する。   The present invention relates to a surface finishing method for ultra high strength fiber reinforced concrete.

近年、構造部材の軽量化、鉄筋使用量の削減などの要求に伴い、圧縮強度150N/mm以上、引張強度8.8N/mm以上、ひび割れ発生強度8.0N/mm以上の超高強度材料が提案されている。
超高強度繊維補強コンクリートは、高強度・高耐久といった性能を発揮するため、通常のコンクリートよりも多くの結合材が使用されている。このため、使用される環境温度によってその硬化速度も大きく影響される。超高強度繊維補強コンクリートを熟知した技術者であれば製造や施工は容易だが、未だ多く普及していないため本コンクリートに精通した技術者が少ないのが現状である。特に打込み後の表面仕上げ時期は、環境温度に大きく影響され、一般的なコンクリートとは異なり、技術者の感覚のみでは判断できない。これまで、コンクリートの表面仕上げ時期判定方法には、予めコンクリート中に埋め込んだ電極の電気抵抗を測定し、その変化から表面仕上げ時期を判定する方法が提案されている(特許文献1)。
Recently, weight reduction of the structural member, with the requests, such as reduction of rebar consumption, compression strength 150 N / mm 2 or more, a tensile strength of 8.8 N / mm 2 or more, Cracking strength 8.0 N / mm 2 or more ultra-high Strength materials have been proposed.
Ultra-high-strength fiber reinforced concrete exhibits performances such as high strength and high durability, and therefore more binders are used than ordinary concrete. For this reason, the curing speed is greatly influenced by the environmental temperature used. Engineers who are familiar with ultra-high-strength fiber-reinforced concrete are easy to manufacture and install, but since there are not many of them yet, there are few engineers who are familiar with this concrete. In particular, the surface finishing time after placing is greatly influenced by the environmental temperature, and unlike ordinary concrete, it cannot be judged only by the sense of an engineer. Conventionally, as a method for determining the surface finish time of concrete, a method has been proposed in which the electrical resistance of an electrode embedded in concrete in advance is measured and the surface finish time is determined from the change (Patent Document 1).

特開平5−340938号公報JP-A-5-340938

しかしながら、特許文献1に記載されている表面仕上げ時期の判定方法では、設備が大がかりであること、操作が煩雑であること、必ず電源が必要なこと、超高強度繊維補強コンクリートの場合、センサを埋殺すとセンサとコンクリート界面やセンサ自体が欠陥となる恐れがある。
そこで、本発明は上記問題点を解決し、簡便かつ低コストに超高強度繊維補強コンクリートの表面仕上げを行う超高強度繊維補強コンクリートの表面仕上げ方法を提供することを目的とする。
However, in the method for determining the surface finishing time described in Patent Document 1, the equipment is large, the operation is complicated, the power supply is always required, and in the case of ultra high strength fiber reinforced concrete, the sensor is used. If buried, the sensor-concrete interface and the sensor itself may become defective.
Accordingly, an object of the present invention is to solve the above-described problems and to provide a surface finishing method for ultra high strength fiber reinforced concrete that performs surface finishing of ultra high strength fiber reinforced concrete easily and at low cost.

本発明者らは上記目的を達成すべく鋭意検討した結果、特定形状の硬度計を接触させ貫入抵抗値を測定し、貫入抵抗値が所定の値を示す時期に前記超高強度繊維補強コンクリートの表面を仕上げることで、簡便かつ低コストで表面仕上げ状態が良好な表面仕上げ方法が得られることを見出し、本発明を完成するに至った。   As a result of intensive studies to achieve the above-mentioned object, the present inventors contact a hardness meter of a specific shape to measure a penetration resistance value, and when the penetration resistance value shows a predetermined value, the ultra high strength fiber reinforced concrete is By finishing the surface, it was found that a surface finishing method having a good surface finishing state can be obtained easily and at low cost, and the present invention has been completed.

すなわち、本発明は、超高強度繊維補強コンクリートを型枠に流し込み養生する第1工程と、前記超高強度繊維補強コンクリートの表面に先端部が錘体形状をした硬度計を接触させ、貫入抵抗値を測定する第2工程と、前記貫入抵抗値が所定の値を示す時期に前記超高強度繊維補強コンクリートの表面を仕上げる第3工程とを含む、超高強度繊維補強コンクリートの表面仕上げ方法に関する。この方法によれば、施工業者の熟練度に影響されず、簡便な方法で、精度の高い表面仕上げを行うことが可能である。   That is, the present invention comprises a first step of pouring and curing ultra-high strength fiber reinforced concrete into a mold, and a hardness meter having a tip shape of a weight on the surface of the ultra high strength fiber reinforced concrete so that the penetration resistance A surface finishing method for ultra-high-strength fiber reinforced concrete, comprising: a second step of measuring a value; and a third step of finishing the surface of the ultra-high-strength fiber reinforced concrete at a time when the penetration resistance value exhibits a predetermined value. . According to this method, it is possible to perform highly accurate surface finishing by a simple method without being affected by the skill level of the contractor.

また、本発明は、前記貫入抵抗値の所定の値が0.5〜4.0N/mmである、超高強度繊維補強コンクリートの表面仕上げ方法に関する。この範囲であれば、より精度の高い表面仕上げが可能となる。 Moreover, this invention relates to the surface finishing method of the ultra high strength fiber reinforced concrete whose predetermined value of the said penetration resistance value is 0.5-4.0N / mm < 2 >. Within this range, a more accurate surface finish can be achieved.

本発明によれば、施工業者の熟練度に影響されず、簡便な方法で、精度の高い表面仕上げを行うことが可能な超高強度繊維補強コンクリートの表面仕上げ方法を提供することができる。   ADVANTAGE OF THE INVENTION According to this invention, the surface finishing method of the ultra high strength fiber reinforced concrete which can perform a highly accurate surface finishing by a simple method without being influenced by the skill level of a contractor can be provided.

本発明に係る山中式土壌硬度計を撮影した写真である。It is the photograph which image | photographed the Yamanaka type | system | group soil hardness meter which concerns on this invention. 比較用として使用したスプリング式プロクター貫入試験機を撮影した写真である。It is the photograph which image | photographed the spring type | mold proctor penetration tester used for the comparison. 山中式土壌硬度計を使用した場合の経過時間と貫入抵抗値の関係を表すグラフである。It is a graph showing the relationship of elapsed time and penetration resistance value at the time of using a Yamanaka type soil hardness meter. スプリング式プロクター貫入試験機を使用した場合の経過時間と貫入抵抗値の関係を表すグラフである。It is a graph showing the relationship between elapsed time and penetration resistance value at the time of using a spring type proctor penetration tester. 山中式硬度計とスプリング式プロクター貫入試験機の貫入抵抗値の変動係数を比較したグラフである。It is the graph which compared the variation coefficient of the penetration resistance value of a Yamanaka type hardness meter and a spring type proctor penetration tester. 山中式土壌硬度計を使用した場合のコンクリート内部のイメージ図である。It is an image figure inside the concrete at the time of using a Yamanaka type soil hardness meter. スプリング式プロクター貫入試験機を使用した場合のコンクリート内部のイメージ図である。It is an image figure inside the concrete at the time of using a spring type | mold proctor penetration testing machine. 山中式土壌硬度計を使用した場合の貫入抵抗値を示すグラフである。It is a graph which shows the penetration resistance value at the time of using a Yamanaka type soil hardness meter. スプリング式プロクター貫入試験機を使用した場合の貫入抵抗値を表すグラフである。It is a graph showing the penetration resistance value at the time of using a spring type proctor penetration tester.

以下、本発明の好適な実施形態について説明する。   Hereinafter, preferred embodiments of the present invention will be described.

本発明は、超高強度繊維補強コンクリートを型枠に流し込み養生する第1工程と、前記超高強度繊維補強コンクリートの表面に先端部が錘体形状をした硬度計を接触させ、貫入抵抗値を測定する第2工程と、前記貫入抵抗値が所定の値を示す時期に前記超高強度繊維補強コンクリートの表面を仕上げる第3工程とを含む、超高強度繊維補強コンクリートの表面仕上げ方法である。   The present invention comprises a first step of pouring and curing ultra high strength fiber reinforced concrete into a mold, and a hardness meter having a tip-shaped body in contact with the surface of the ultra high strength fiber reinforced concrete so as to obtain a penetration resistance value. A surface finishing method for ultra high strength fiber reinforced concrete, comprising a second step of measuring and a third step of finishing the surface of the ultra high strength fiber reinforced concrete at a time when the penetration resistance value exhibits a predetermined value.

本発明の第1工程で使用する型枠は、金属製や木製の型枠等が挙げられる。
養生には、屋外での常温養生、管理された温度制御養生および保温養生、コンクリート製品工場で実施される給熱養生等が挙げられる。
Examples of the mold used in the first step of the present invention include metal and wooden molds.
Curing includes outdoor normal temperature curing, controlled temperature control curing and heat curing, heat curing performed in a concrete product factory, and the like.

本発明に関わる超高強度繊維補強コンクリートとは、土木学会 コンクリートライブラリー113「超高強度繊維補強コンクリートの設計・施工指針(案)」で規定される、圧縮強度が150N/mm以上、ひび割れ発生強度が4N/mm以上、引張強度が5N/mm以上を示す繊維補強を行ったセメント質複合材をいう。 The ultra high strength fiber reinforced concrete according to the present invention is defined by the Japan Society of Civil Engineers concrete library 113 "Design and Construction guidelines for ultra high strength fiber reinforced concrete (draft)", compressive strength 150 N / mm 2 or more, cracks It refers to a cementitious composite material that has been subjected to fiber reinforcement with a generated strength of 4 N / mm 2 or more and a tensile strength of 5 N / mm 2 or more.

第2工程で使用する硬度計は、先端部が錘体形状をしており、円錐状または角錘状であることが好ましい。円錐状の中でも、JHS規格(日本道路公団試験規格JHS 601「土壌硬度試験方法」)で規定される土壌硬度計が、本発明の表面仕上げ方法を適用する上でより好ましい。土壌硬度計の中でも山中式土壌硬度計がより好ましい。
山中式土壌硬度計を使用して貫入抵抗値を測定する際は、JHS 604「土壌貫入試験方法」に準じて測定する。
In the hardness meter used in the second step, the tip portion has a pyramid shape, and is preferably conical or pyramidal. Among the cones, a soil hardness meter defined by the JHS standard (Japan Highway Public Corporation Test Standard JHS 601 “Soil Hardness Test Method”) is more preferable in applying the surface finishing method of the present invention. Among the soil hardness meters, the Yamanaka type soil hardness meter is more preferable.
When the penetration resistance value is measured using a Yamanaka type soil hardness tester, it is measured according to JHS 604 “Soil penetration test method”.

第3工程で超高強度繊維補強コンクリートの表面を仕上げる時期は、貫入抵抗値が所定の値を示す時期である。所定の値とは貫入抵抗値が0.5〜4.0N/mmとなった時期が好ましく、より好ましくは0.7〜3.0N/mm、更に好ましくは0.9〜2.0N/mmとなった時期である。これらの時期に表面仕上げを行うと、仕上げコテに超高強度繊維補強コンクリートが付着しないため仕上げがし易く、また、内部の硬化も適度に進んでいることから、表面仕上げ中にひび割れが生じる恐れがない。また適度な硬化が得られる状態であるため、仕上げコテで表面の凹凸や気泡痕等が除去し易く、より良い表明仕上げが行える。
表面を仕上げる方法は、金属ゴテや木ゴテ等で平滑にする方法や表面仕上げ用のバイブレータ等で平滑性を付与する方法が挙げられる。
The time when the surface of the ultra high strength fiber reinforced concrete is finished in the third step is a time when the penetration resistance value shows a predetermined value. The predetermined value is preferably a time when the penetration resistance value becomes 0.5 to 4.0 N / mm 2 , more preferably 0.7 to 3.0 N / mm 2 , and still more preferably 0.9 to 2.0 N. / Mm 2 . If surface finishing is performed during these periods, the ultra-high-strength fiber reinforced concrete does not adhere to the finishing iron, making it easy to finish, and the internal hardening has also progressed moderately, which may cause cracks during surface finishing. There is no. Moreover, since it is in a state where moderate curing can be obtained, it is easy to remove surface irregularities, bubble traces and the like with a finishing trowel, and a better manifestation finish can be performed.
Examples of the method of finishing the surface include a method of smoothing with a metal trowel or wood trowel, and a method of imparting smoothness with a vibrator for surface finishing.

本発明の対象とする超高強度繊維補強コンクリートの材料構成は、セメント、シリカフューム、無機質微粉末、細骨材、減水剤、水及び繊維を含むことが、本発明の表面仕上げ方法を適用する上で好ましい。   In addition to applying the surface finishing method of the present invention, the material composition of the ultra high strength fiber reinforced concrete targeted by the present invention includes cement, silica fume, fine inorganic powder, fine aggregate, water reducing agent, water and fiber. Is preferable.

セメントは普通セメント、早強セメント、高炉セメント、フライアッシュセメント、シリカフュームセメント、低熱セメント、耐硫酸塩セメント、油井セメント等を使用することが出来る。セメントのブレーン比表面積は2500〜4800cm/g、好ましくは2800〜4000cm/g、より好ましくは3000〜3600cm/g、更に好ましくは3100〜3500cm/gである。これらの範囲であれば、本発明の表面仕上げ方法を適用した場合に、適用しない場合に比べ、本発明の効果をより発揮出来る。 As the cement, ordinary cement, early-strength cement, blast furnace cement, fly ash cement, silica fume cement, low heat cement, sulfate resistant cement, oil well cement and the like can be used. The brane specific surface area of the cement is 2500 to 4800 cm 2 / g, preferably 2800 to 4000 cm 2 / g, more preferably 3000 to 3600 cm 2 / g, and further preferably 3100 to 3500 cm 2 / g. Within these ranges, the effect of the present invention can be more exhibited when the surface finishing method of the present invention is applied than when it is not applied.

シリカフュームは、金属シリコン、フェロシリコン、電融ジルコニア等を製造する際に、発生する排ガス中のダストを集塵して得られる副産物であり、主成分は、アルカリ溶液中で溶解する非晶質のSiOである。シリカフュームのBET比表面積は、好ましくは15〜25m/g、より好ましくは16〜22m/g、更に好ましくは17〜21m/g、平均粒子径は0.05〜2.0μm、好ましくは0.10〜1.50μm、更に好ましくは0.18〜0.28μmである。これらの範囲であれば、本発明の表面仕上げ方法を適用した場合に、適用しない場合に比べ、本発明の効果をより発揮出来る。 Silica fume is a byproduct obtained by collecting dust in the exhaust gas generated when producing metal silicon, ferrosilicon, fused zirconia, etc., and the main component is an amorphous substance that dissolves in an alkaline solution. SiO 2 . Silica fume preferably has a BET specific surface area of 15 to 25 m 2 / g, more preferably 16 to 22 m 2 / g, still more preferably 17 to 21 m 2 / g, and an average particle size of 0.05 to 2.0 μm, preferably The thickness is 0.10 to 1.50 μm, more preferably 0.18 to 0.28 μm. Within these ranges, the effect of the present invention can be more exhibited when the surface finishing method of the present invention is applied than when it is not applied.

また、無機質微粉末としては、石灰石粉、珪石粉、砕石粉等を使用することができる。無機質微粉末は、石灰石粉、珪石粉、砕石粉等をブレーン比表面積が2500cm/g以上となるまで粉砕又は分級した微粉末であり、細骨材の微粒分を補う目的で配合され、超高強度繊維補強コンクリートの流動性を改善することができる。無機質微粉末のブレーン比表面積は3000〜5000cm/gであることが好ましく、3200〜4500cm/gであることがより好ましく、3400〜4300cm/gであることが更に好ましい。これらの範囲であれば、本発明の表面仕上げ方法を適用した場合に、適用しない場合に比べ、本発明の効果をより発揮出来る。 Moreover, limestone powder, quartzite powder, crushed stone powder, etc. can be used as the inorganic fine powder. The inorganic fine powder is a fine powder obtained by pulverizing or classifying limestone powder, quartzite powder, crushed stone powder or the like until the Blaine specific surface area is 2500 cm 2 / g or more, and is blended for the purpose of supplementing fine particles of fine aggregate, The fluidity of high strength fiber reinforced concrete can be improved. Preferably Blaine specific surface area of the powder inorganic fine powder is 3000~5000cm 2 / g, more preferably 3200~4500cm 2 / g, and further preferably from 3400~4300cm 2 / g. Within these ranges, the effect of the present invention can be more exhibited when the surface finishing method of the present invention is applied than when it is not applied.

細骨材としては、川砂、陸砂、海砂、砕砂、珪砂、石灰石骨材、高炉スラグ細骨材、フェロニッケルスラグ細骨材、銅スラグ細骨材、電気炉酸化スラグ細骨材等を使用することができる。なお、細骨材の粒度は、10mmふるいを全部通り、5mmふるいを85質量%以上通過するものが好ましい。粗粒率は1.5〜4.0、好ましくは2.0〜3.5、より好ましくは2.5〜3.0である。これらの範囲であれば、本発明の表面仕上げ方法を適用した場合に、適用しない場合に比べ、本発明の効果をより発揮出来る。   Fine aggregates include river sand, land sand, sea sand, crushed sand, quartz sand, limestone aggregate, blast furnace slag fine aggregate, ferronickel slag fine aggregate, copper slag fine aggregate, electric furnace oxidation slag fine aggregate, etc. Can be used. The fine aggregate preferably has a particle size of passing through a 10 mm sieve and passing through a 5 mm sieve by 85% by mass or more. The coarse particle ratio is 1.5 to 4.0, preferably 2.0 to 3.5, more preferably 2.5 to 3.0. Within these ranges, the effect of the present invention can be more exhibited when the surface finishing method of the present invention is applied than when it is not applied.

減水剤としては、リグニン系、ナフタレンスルホン酸系、アミノスルホン酸系、ポリカルボン酸系の減水剤、高性能減水剤、高性能AE減水剤等を使用することができる。低水セメント比での流動性確保の観点から、減水剤として、ポリカルボン酸系の減水剤、高性能減水剤又は高性能AE減水剤を用いることが好ましく、ポリカルボン酸系の高性能減水剤を用いることがより好ましい。これらの範囲であれば、本発明の表面仕上げ方法を適用した場合に、適用しない場合に比べ、本発明の効果をより発揮出来る。   As the water reducing agent, lignin-based, naphthalenesulfonic acid-based, aminosulfonic acid-based, polycarboxylic acid-based water reducing agents, high-performance water reducing agents, high-performance AE water reducing agents, and the like can be used. From the viewpoint of ensuring fluidity at a low water cement ratio, it is preferable to use a polycarboxylic acid-based water reducing agent, a high-performance water reducing agent or a high-performance AE water reducing agent as the water reducing agent, and a polycarboxylic acid-based high-performance water reducing agent. It is more preferable to use Within these ranges, the effect of the present invention can be more exhibited when the surface finishing method of the present invention is applied than when it is not applied.

繊維は、鋼繊維、ステンレス繊維、アモルファス合金繊維等の金属繊維や、炭素繊維、アラミド繊維、ナイロン、ポリプロピレン等の有機繊維等が挙げられる。このような高張力繊維を用いることで、モルタル組成物に高いじん性および引張強度を付与することができる。高張力繊維を使用する場合の密度は1〜20g/cm3、好ましくは3〜15g/cm、より好ましくは5〜10g/cmである。 Examples of the fibers include metal fibers such as steel fibers, stainless steel fibers, and amorphous alloy fibers, and organic fibers such as carbon fibers, aramid fibers, nylon, and polypropylene. By using such a high-tensile fiber, high toughness and tensile strength can be imparted to the mortar composition. The density when using high-tensile fibers is 1 to 20 g / cm 3, preferably 3 to 15 g / cm 3 , more preferably 5 to 10 g / cm 3 .

また、前記セメント100質量部に対して、シリカフューム3〜30質量部、好ましくは5〜20質量部、より好ましくは10〜18質量部、無機質微粉末5〜50質量部、好ましくは10〜40質量部、より好ましくは20〜30質量部、細骨材5〜50質量部、好ましくは10〜40質量部、より好ましくは20〜30質量部、減水剤0.1〜5質量部、好ましくは0.5〜4質量部、より好ましくは1〜3質量部、水5〜30質量部、好ましくは7〜20質量部、より好ましくは10〜18質量部、及び鋼繊維1〜30質量部、好ましくは1〜20質量部、より好ましくは1〜15質量部を含む。これらの範囲であれば、本発明の表面仕上げ方法を適用した場合に、適用しない場合に比べ、本発明の効果をより発揮出来る。   Moreover, 3 to 30 parts by mass of silica fume, preferably 5 to 20 parts by mass, more preferably 10 to 18 parts by mass, and 5 to 50 parts by mass of inorganic fine powder, preferably 10 to 40 parts by mass with respect to 100 parts by mass of the cement. Parts, more preferably 20-30 parts by weight, fine aggregate 5-50 parts by weight, preferably 10-40 parts by weight, more preferably 20-30 parts by weight, water reducing agent 0.1-5 parts by weight, preferably 0. 5-4 parts by weight, more preferably 1-3 parts by weight, water 5-30 parts by weight, preferably 7-20 parts by weight, more preferably 10-18 parts by weight, and steel fibers 1-30 parts by weight, preferably 1-20 parts by mass, more preferably 1-15 parts by mass. Within these ranges, the effect of the present invention can be more exhibited when the surface finishing method of the present invention is applied than when it is not applied.

以下に、実施例及び比較例を挙げて本発明の内容を詳細に説明する。なお、本発明はこれらの例によって限定されるものではない。   The contents of the present invention will be described in detail below with reference to examples and comparative examples. Note that the present invention is not limited to these examples.

1.超高強度繊維補強コンクリートの製造
(1)使用材料
試験体の製造には以下の材料を用いた。
・セメント(ブレーン比表面積:3300cm/g)
・シリカフューム(平均粒径:0.23μm)
・無機質微粉末:石灰石粉(ブレーン比表面積:3850cm/g)
・細骨材(粒径5mm以下、粗粒率:2.81)
・減水剤(ポリカルボン酸系高性能減水剤)
・水(上水道水)
・鋼繊維(密度7.85g/cm
(2)調合および練混ぜ
上記材料をセメント100質量部に対してシリカフュームを14質量部、細骨材を25質量部、石灰石微粉末を26質量部、混和剤を2質量部、水を17質量部の割合で混合し、強制二軸ミキサで練混ぜてモルタルを製造した。鋼繊維は練りあがったモルタルにほぐしながらセメント100質量部に対して12質量部添加したものと、添加してないものの2種類を製造した。
(3)試験体の成形
上記の方法で製造したモルタルを縦20×横20×高さ5cm、縦20×横20×高さ10cm、縦20×横20×高さ20cmの3種類の型枠に流し込み評価用試験体を成形した。
(4)試験体の養生
上記の試験体は温度20℃、湿度60%の恒温室で養生した。
1. Production of ultra-high strength fiber reinforced concrete (1) Materials used The following materials were used for the production of test specimens.
Cement (Blaine specific surface area: 3300 cm 2 / g)
Silica fume (average particle size: 0.23 μm)
・ Inorganic fine powder: Limestone powder (Blaine specific surface area: 3850 cm 2 / g)
・ Fine aggregate (particle size 5mm or less, coarse particle ratio: 2.81)
・ Water reducing agent (Polycarboxylic acid-based high-performance water reducing agent)
・ Water (tap water)
Steel fiber (density 7.85 g / cm 3 )
(2) Preparation and kneading 14 parts by mass of silica fume, 25 parts by mass of fine aggregate, 26 parts by mass of fine limestone powder, 2 parts by mass of admixture, and 17 parts by mass of water with respect to 100 parts by mass of cement. The mortar was manufactured by mixing at a part ratio and kneading with a forced biaxial mixer. Two types of steel fibers were produced: 12 mass parts added with respect to 100 mass parts of cement and those not added while loosening the kneaded mortar.
(3) Molding of Specimen Three types of mortar produced by the above method are 20 × 20 × 5cm in height, 20 × 20 × 10 × 10 cm in height, 20 × 20 in 20 × 20 in height. A test specimen for casting evaluation was molded.
(4) Curing of Specimen The above specimen was cured in a temperature-controlled room at a temperature of 20 ° C. and a humidity of 60%.

2.貫入抵抗値の測定
(1)貫入抵抗値の測定機器
次に、準備した超高強度繊維補強コンクリート試験体の表面の貫入抵抗値の測定を行った。測定に使用したのは山中式土壌硬度計である。その性能を下表に示す。山中式土壌硬度計とは日本道路公団規格のJHS 601「土壌硬度試験方法」に規定される土壌硬度計である。図1に山中式土壌硬度計を撮影した写真を示す。
2. Measurement of Penetration Resistance Value (1) Measuring Instrument for Penetration Resistance Value Next, the penetration resistance value of the prepared ultra high strength fiber reinforced concrete specimen was measured. The Yamanaka soil hardness tester was used for the measurement. The performance is shown in the table below. The Yamanaka type soil hardness tester is a soil hardness tester defined in JHS 601 “Soil Hardness Test Method” of the Japan Highway Public Corporation Standard. FIG. 1 shows a photograph of a Yamanaka soil hardness tester.

Figure 0006256053
Figure 0006256053

また、比較としてスプリング式プロクター貫入試験機を使用して貫入抵抗値の測定を行った。スプリング式プロクター貫入試験機とはJIS A 1147「コンクリートの凝結試験方法」に規定されるコンクリートの貫入抵抗を測定する試験機である。図2にスプリング式プロクター貫入試験機を撮影した写真を示す。   For comparison, the penetration resistance value was measured using a spring type proctor penetration tester. The spring type proctor penetration tester is a tester for measuring the penetration resistance of concrete as defined in JIS A 1147 “Concrete setting test method”. FIG. 2 shows a photograph of the spring type proctor penetration tester.

Figure 0006256053
Figure 0006256053

(2)コンクリート表面硬度の測定
次に、上述した山中式土壌硬度計を用い、日本道路公団規格JHS 601「土壌硬度試験方法」に準じて、超高強度繊維補強コンクリートの硬度を測定した。測定は試験体表面の異なる箇所3点を任意に選び、コンクリートを作成する際の注水後から、6時間、7時間15分、8時間30分、8時間55分、9時間10分の各時間経過後に測定した。なお、9時間10分経過した時点で、コンクリートの表面はほぼ硬化した。
(2) Measurement of concrete surface hardness Next, the hardness of the ultra-high strength fiber reinforced concrete was measured according to the Japan Highway Public Corporation Standard JHS 601 “Soil Hardness Test Method” using the above-mentioned Yamanaka soil hardness tester. The measurement is arbitrarily selected from three different points on the surface of the test specimen, and 6 hours, 7 hours and 15 minutes, 8 hours and 30 minutes, 8 hours and 55 minutes, and 9 hours and 10 minutes after pouring water when creating concrete. It was measured after the lapse. When 9 hours and 10 minutes passed, the surface of the concrete was almost cured.

具体的な測定方法は、以下の通りである。まず、硬度計の指標を0に戻し、測定面に対して硬度計を正しく垂直に立て、突き当てツバが完全に測定面に接触するまで、徐々に円錐体を圧入する。その際、突き当てツバと測定面の間に隙間が空かないように注意した。レキに突き当たった場合は、そこを避けて測定し直す。円錐体が完全に圧入したら、硬度計を静かに抜き取り、指標の示す位置の目盛を読み取る。その値を用いて、硬度計に付属している硬度指数と支持力強度との対照表か貫入抵抗値を算出する。   A specific measurement method is as follows. First, the index of the hardness meter is returned to 0, the hardness meter is set up vertically correctly with respect to the measurement surface, and the cone is gradually press-fitted until the butting flange completely contacts the measurement surface. At that time, care was taken not to leave a gap between the abutment flange and the measurement surface. If you hit the reki, avoid it and measure again. When the cone is completely press-fitted, gently remove the hardness tester and read the scale at the position indicated by the index. Using the value, a comparison table of hardness index and bearing strength attached to the hardness meter or penetration resistance value is calculated.

測定結果を表3に示す。また、経過時間と貫入抵抗値の関係を示したグラフを図3に示す。なおグラフ中の各プロットは表3の測定結果の平均値を採用した。図3より、注水後からの経過時間と貫入抵抗値とは曲線的な関係にあることがわかる。   Table 3 shows the measurement results. Moreover, the graph which showed the relationship between elapsed time and penetration resistance value is shown in FIG. Each plot in the graph adopted the average value of the measurement results in Table 3. It can be seen from FIG. 3 that the elapsed time after water injection and the penetration resistance value are in a curved relationship.

各貫入抵抗値を示した時期に金ゴテで表面仕上げを行った際の評価結果を表4に示す。貫入抵抗値が0.5〜4.0N/mmに達した時期に表面仕上げを行うと、仕上げコテに超高強度繊維補強コンクリートが付着しないため仕上げがし易く、また、内部の硬化も適度に進んでいることから、表面仕上げ中にひび割れが生じる恐れがなかった。また適度な硬化が得られる状態であるため、仕上げコテで表面の凹凸や気泡痕等が除去し易く、より良い表面仕上げが行えることがわかった。 Table 4 shows the evaluation results when surface finishing was performed with a gold trowel at the time when each penetration resistance value was shown. If the surface finish is performed when the penetration resistance value reaches 0.5 to 4.0 N / mm 2 , the ultra-high-strength fiber reinforced concrete does not adhere to the finishing iron, and finishing is easy, and the internal hardening is also moderate. Therefore, there was no risk of cracking during the surface finishing. Moreover, since it was in the state in which moderate hardening was obtained, it turned out that the surface unevenness | corrugation, a bubble trace, etc. are easy to remove with a finishing iron, and a better surface finish can be performed.

同様に、スプリング式プロクター貫入試験機を用いて、超高強度繊維補強コンクリートの表面硬度を測定した。測定方法は、JIS A 1147「コンクリートの凝結時間試験方法」に準じて測定した。具体的には、試料の硬化状態に応じて適切な断面積をもつ貫入針(断面積:100mm、50mm、25mm)を選び、貫入抵抗試験機に取り付け、貫入針を試料中に注意深く鉛直下方に25mm貫入させた。貫入の深さは、貫入針につけた刻印で確かめ、貫入に有する時間は約10秒とし、貫入試験を行った時刻及び貫入に要した力(N)を装置から読み取って記録した。貫入に要した力(N)を用いた貫入針の断面積(mm)で除し、四捨五入によって、小数点1けたに丸め、貫入抵抗値とした。 Similarly, the surface hardness of ultra high strength fiber reinforced concrete was measured using a spring type proctor penetration tester. The measuring method was measured according to JIS A 1147 “Concrete setting time test method”. Specifically, a penetrating needle (cross-sectional area: 100 mm 2 , 50 mm 2 , 25 mm 2 ) having an appropriate cross-sectional area is selected according to the cured state of the sample, is attached to a penetrating resistance tester, and the penetrating needle is carefully inserted into the sample. It penetrated 25 mm vertically downward. The depth of penetration was confirmed by an inscription on the penetration needle. The penetration time was about 10 seconds, and the time of penetration test and the force (N) required for penetration were read from the apparatus and recorded. Dividing by the cross-sectional area (mm 2 ) of the penetrating needle using the force (N) required for penetrating, it was rounded off to the first decimal place by rounding off to obtain the penetration resistance value.

測定結果を表3に示す。また、経過時間と貫入抵抗値の関係を示したグラフを図4に示す。なおグラフ中の各プロットは表3の測定結果の平均値を採用した。図4より、スプリング式プロクター貫入試験機でも、経過時間と貫入抵抗値とは曲線的な関係にあることがわかる。   Table 3 shows the measurement results. Moreover, the graph which showed the relationship between elapsed time and penetration resistance value is shown in FIG. Each plot in the graph adopted the average value of the measurement results in Table 3. From FIG. 4, it can be seen that the elapsed time and the penetration resistance value have a curved relationship even in the spring type proctor penetration tester.

Figure 0006256053
Figure 0006256053

Figure 0006256053
Figure 0006256053

(3)試験方法の比較
両試験機器を比較すると、表3及び図5より、スプリング式プロクター貫入試験機の場合、繊維入りモルタルを測定した場合の測定値の変動係数の平均値が山中式硬度計よりも大きくなっていることがわかる。具体的には、高さ5cmの試験体の場合、スプリング式プロクター貫入試験機は0.32(0.38、0.29、0.34、0.28の平均)に対し、山中式土壌硬度計は0.15、高さ10cmの試験体の場合、各々0.38、0.12、高さ20cmの試験体の場合、各々0.45、0.19となっている。
(3) Comparison of test methods Comparing both test devices, from Table 3 and FIG. 5, in the case of a spring type proctor penetration tester, the average value of the coefficient of variation of the measured value when measuring the mortar with fiber is Yamanaka hardness It can be seen that it is larger than the total. Specifically, in the case of a specimen having a height of 5 cm, the spring type Procter penetration tester is 0.32 (average of 0.38, 0.29, 0.34, 0.28), while the Yamanaka type soil hardness is The totals are 0.15 and 0.38 and 0.12, respectively, in the case of a 10 cm high specimen, and 0.45 and 0.19 in the case of a 20 cm high specimen, respectively.

この理由は、山中式土壌硬度計の場合、貫入部位が円錐形のため接触部の単位面積当たりの内部繊維量の影響を受けにくいのに対し(図6)、スプリング式プロクター貫入試験機の場合、貫入部位が円筒形のため、接触部の単位面積当たりの繊維量の影響を受けやすく(図7)、測定箇所に偏って繊維が存在するかどうかで貫入抵抗値が変動するからと推察される。両試験器の単位面積当たりの繊維量の影響の受けやすさは、鋼繊維有りと鋼繊維無しのモルタルの貫入抵抗値の差を比較すれば明らかで、山中式土壌硬度計に比べ、スプリング式プロクター貫入試験機の方が、抵抗値の差が大きく、抵抗値自体もスプリング式プロクター貫入試験機の方が大きい(図8、9)。
以上のように、山中式土壌硬度計を使用して貫入抵抗値を測定し、その貫入抵抗値が特定の範囲を示す時期に表面仕上げを行えば、超高強度繊維補強コンクリートという特殊なコンクリートであっても施工技術者の感覚に依存することなく、良好な表面仕上げを行える。
The reason for this is that in the case of the Yamanaka soil hardness tester, the penetration site is conical and is not easily affected by the amount of internal fibers per unit area of the contact area (Fig. 6). Because the penetration site is cylindrical, it is likely to be affected by the amount of fiber per unit area of the contact area (Fig. 7), and it is assumed that the penetration resistance value varies depending on whether there is a fiber biased at the measurement location. The The susceptibility of both testers to the amount of fibers per unit area is obvious by comparing the difference in penetration resistance between mortars with and without steel fibers, compared to the Yamanaka soil hardness tester. The difference in resistance value is larger in the Proctor penetration tester, and the resistance value itself is larger in the spring type Procter penetration tester (FIGS. 8 and 9).
As described above, if the penetration resistance value is measured using a Yamanaka-type soil hardness meter and the surface finish is performed at a time when the penetration resistance value shows a specific range, a special concrete called ultra-high-strength fiber reinforced concrete is used. Even if there is, good surface finish can be performed without depending on the sense of construction engineers.

Claims (8)

超高強度繊維補強コンクリートを型枠に流し込み養生する第1工程と、
前記超高強度繊維補強コンクリートの表面に先端部が錘体形状をした硬度計を接触させ、貫入抵抗値を測定する第2工程と、
前記貫入抵抗値が所定の値を示す時期に前記超高強度繊維補強コンクリートの表面を仕上げる第3工程とを含むことを特徴とする超高強度繊維補強コンクリートの表面仕上げ方法。
A first step of pouring and curing ultra-high-strength fiber reinforced concrete into a mold,
A second step of measuring a penetration resistance value by contacting a hardness meter having a tip-shaped body on the surface of the ultra high strength fiber reinforced concrete;
And a third step of finishing the surface of the ultra-high-strength fiber reinforced concrete at a time when the penetration resistance value shows a predetermined value.
前記錘体形状が円錐状または角錘状である、請求項1記載の超高強度繊維補強コンクリートの表面仕上げ方法。   The surface finishing method for ultra-high-strength fiber-reinforced concrete according to claim 1, wherein the weight shape is conical or prismatic. 前記硬度計が土壌硬度計である、請求項1又は2記載の超高強度繊維補強コンクリートの表面仕上げ方法。   The surface finishing method of the ultra high strength fiber reinforced concrete according to claim 1 or 2, wherein the hardness meter is a soil hardness meter. 前記貫入抵抗値の所定の値が0.5〜4.0N/mmである、請求項1〜3の何れか1項記載の超高強度繊維補強コンクリートの表面仕上げ方法。 It said predetermined value of penetration resistance value is 0.5~4.0N / mm 2, the surface finishing method of the ultra high strength fiber reinforced concrete according to any one of claims 1-3. 前記超高強度繊維補強コンクリートは、セメント、シリカフューム、無機質微粉末、細骨材、減水剤、水及び繊維を含む、請求項1〜4の何れか1項記載の超高強度繊維補強コンクリートの表面仕上げ方法。   The surface of the ultra high strength fiber reinforced concrete according to any one of claims 1 to 4, wherein the ultra high strength fiber reinforced concrete includes cement, silica fume, inorganic fine powder, fine aggregate, water reducing agent, water and fiber. Finishing method. 前記無機質微粉末は、石灰石粉、珪石粉及び砕石粉からなる群より選ばれる1種以上の微粉末である、請求項1〜5の何れか1項記載の超高強度繊維補強コンクリートの表面仕上げ方法。   The surface finish of the ultra-high-strength fiber reinforced concrete according to any one of claims 1 to 5, wherein the inorganic fine powder is one or more fine powders selected from the group consisting of limestone powder, silica stone powder, and crushed stone powder. Method. 前記セメント100質量部に対して、前記シリカフューム5〜30質量部、前記無機質微粉末5〜50質量部、前記細骨材5〜50質量部、前記減水剤0.1〜5質量部、前記水5〜30質量部及び前記繊維1〜30質量部を含む、請求項5又は6記載の超高強度繊維補強コンクリートの表面仕上げ方法。   5 to 30 parts by mass of the silica fume, 5 to 50 parts by mass of the fine inorganic powder, 5 to 50 parts by mass of the fine aggregate, 0.1 to 5 parts by mass of the water reducing agent, and 100 parts by mass of the water. The surface finishing method of the ultra high strength fiber reinforced concrete according to claim 5 or 6, comprising 5 to 30 parts by mass and 1 to 30 parts by mass of the fiber. 前記繊維は、金属繊維及び/又は有機繊維である、請求項5〜7の何れか1項記載の超高強度繊維補強コンクリートの表面仕上げ方法。   The surface finishing method for ultra-high-strength fiber reinforced concrete according to any one of claims 5 to 7, wherein the fibers are metal fibers and / or organic fibers.
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