JP6937490B2 - Corrosion protection method for steel materials - Google Patents

Corrosion protection method for steel materials Download PDF

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JP6937490B2
JP6937490B2 JP2016206044A JP2016206044A JP6937490B2 JP 6937490 B2 JP6937490 B2 JP 6937490B2 JP 2016206044 A JP2016206044 A JP 2016206044A JP 2016206044 A JP2016206044 A JP 2016206044A JP 6937490 B2 JP6937490 B2 JP 6937490B2
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anticorrosion
steel material
coating
steel
conductive
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徹 山路
徹 山路
善和 審良
善和 審良
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Toray Engineering Co Ltd
National Institute of Maritime Port and Aviation Technology
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Toyo Construction Co Ltd
National Institute of Maritime Port and Aviation Technology
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本発明は、電気防食と被覆防食とを併用する鋼材の防食工法に関するものである。 The present invention relates to an anticorrosion method for steel materials in which both electrocorrosion and coating anticorrosion are used in combination.

従来から、海洋や沿岸等に構築される構造物に用いられる、例えば、鋼管杭や鋼矢板等の鋼材には、防食のために何らかの対策を施すことが必要とされている。このような対策の１つとして、例えば図４には、構造物１２を支える鋼材１４の、干満帯から海底土中部までに電気防食を施し、海上大気部から干潮面（ＬＷＬ）−１．０ｍ程度までに被覆防食を施す、電気防食と被覆防食とを併用する工法を示している（例えば、特許文献１参照）。電気防食では、腐食環境中に設置した電極から鋼材１４に直流電流を通電して、鋼材１４を腐食しない電位にまで変化させることで防食し、被覆防食では、有機被覆材や無機被覆材等で鋼材１４を被覆して、腐食環境から鋼材１４を遮断することで防食する。 Conventionally, it has been necessary to take some measures for corrosion protection of steel materials such as steel pipe piles and steel sheet piles used for structures constructed in the ocean or coast. As one of such measures, for example, in FIG. 4, the steel material 14 supporting the structure 12 is provided with anticorrosion from the ebb and flow zone to the middle part of the seabed soil, and the low tide surface (LWL) -1.0 m from the sea atmosphere part. It shows a construction method in which electric corrosion protection and coating protection are used in combination, in which coating protection is applied to a certain extent (see, for example, Patent Document 1). In electrocorrosion protection, a direct current is applied to the steel material 14 from an electrode installed in a corrosive environment to change the steel material 14 to a potential that does not corrode, thereby preventing corrosion. In coating corrosion protection, an organic coating material or an inorganic coating material is used. Corrosion is prevented by covering the steel material 14 and blocking the steel material 14 from the corrosive environment.

特開平６−１７３２８７号公報Japanese Unexamined Patent Publication No. 6-173287

しかしながら、上述した電気防食と被覆防食とを併用する工法は、電気防食部分に関しては、長期間にわたって比較的安定した防食効果が得られるものの、被覆防食部分に関しては、腐食環境からの遮断が十分に機能せず、被覆材を浸透する塩化物イオンや、大気から供給される酸素によって、鋼材１４の腐食が進行してしまうことがあった。
本発明は上記課題に鑑みてなされたものであり、その目的とするところは、電気防食と被覆防食とを併用する鋼材の、被覆防食部分の防食効果を向上することにある。 However, although the above-mentioned construction method in which the electrocorrosion protection and the coating anticorrosion are used in combination can obtain a relatively stable anticorrosion effect for a long period of time for the electrocorrosion protection portion, the coating corrosion protection portion is sufficiently shielded from the corrosive environment. The steel material 14 may be corroded by chloride ions that do not function and permeate the covering material and oxygen supplied from the atmosphere.
The present invention has been made in view of the above problems, and an object of the present invention is to improve the anticorrosion effect of a coated anticorrosion portion of a steel material in which both electrocorrosion and coating anticorrosion are used in combination.

（発明の態様）
以下の発明の態様は、本発明の構成を例示するものであり、本発明の多様な構成の理解を容易にするために、項別けして説明するものである。各項は、本発明の技術的範囲を限定するものではなく、発明を実施するための最良の形態を参酌しつつ、各項の構成要素の一部を置換し、削除し、又は、更に他の構成要素を付加したものについても、本願発明の技術的範囲に含まれ得るものである。 (Aspect of the invention)
The following aspects of the invention exemplify the configurations of the present invention, and will be described separately in order to facilitate understanding of the various configurations of the present invention. Each section does not limit the technical scope of the present invention, and while taking into consideration the best mode for carrying out the invention, some of the components of each section are replaced, deleted, or further. Those to which the above-mentioned components are added can also be included in the technical scope of the present invention.

（１）電気防食と被覆防食とを併用する鋼材の防食工法において、前記鋼材の被覆防食部分を、導電性を有する被覆材で被覆することによって、前記鋼材の電気防食部分と被覆防食部分との双方に電流を供給する鋼材の防食工法。
本項に記載の鋼材の防食工法は、電気防食と被覆防食とを併用するものであり、鋼材の電気防食部分に対して、流電陽極方式や外部電源方式で電気防食を施すと共に、鋼材の被覆防食部分を、導電性を有する被覆材で被覆する。すると、電気防食のために設置した流電陽極や電極から、鋼材の電気防食部分だけではなく、鋼材の被覆防食部分にも、導電性を有する被覆材を介して、電流が供給される。これにより、鋼材の被覆防食部分は、被覆材によって塩化物イオンや酸素の浸透が抑制されると共に、電流の供給により電位が変化して腐食反応が抑制される。従って、鋼材の被覆防食部分の防食効果を向上するものとなる。 (1) In the anticorrosion method for steel materials in which both electrocorrosion protection and coating anticorrosion are used in combination, the coated anticorrosion portion of the steel material is coated with a conductive coating material so that the electrolytic corrosion protection portion and the coating corrosion protection portion of the steel material are covered with each other. anti-corrosion construction method of steel for supplying current to both.
The anticorrosion method for steel materials described in this section is a combination of electrocorrosion protection and coating anticorrosion. The anticorrosive portion is coated with a conductive coating material. Then, a current is supplied from the galvanic anode and the electrode installed for the electric corrosion protection not only to the electric corrosion protection portion of the steel material but also to the coating corrosion protection portion of the steel material through the conductive coating material. As a result, in the coated anticorrosive portion of the steel material, the permeation of chloride ions and oxygen is suppressed by the coating material, and the potential is changed by the supply of the electric current to suppress the corrosion reaction. Therefore, the anticorrosion effect of the coated anticorrosion portion of the steel material is improved.

（２）上記（１）項において、前記被覆材として、カーボンサンドを含んだ導電モルタルを用い、このとき、前記カーボンサンドの添加量を変えて流入電流密度を試算した前記導電モルタルの試算結果に基づいて、前記導電モルタルへの前記カーボンサンドの添加量を調整する鋼材の防食工法（請求項１）。
本項に記載の鋼材の防食工法は、鋼材の被覆防食部分を被覆する被覆材として、カーボンサンドを含んだ導電モルタルを用いるものである。すなわち、一般的に用いられる被覆材の１つであるモルタルに対して、比較的入手が容易なカーボンサンドを細骨材や粉体として添加することで、モルタルに導電性を付与する。この際、モルタルの導電率は、カーボンサンドの添加量等によって調整する。このような導電モルタルを用いることで、コストを抑制しながら、鋼材の被覆防食部分の防食効果を高めるものである。 (2) In the above item (1), a conductive mortar containing carbon sand is used as the coating material , and at this time, the inflow current density is calculated by changing the addition amount of the carbon sand. Based on this, a method for preventing corrosion of steel materials (claim 1 ), which adjusts the amount of the carbon sand added to the conductive mortar.
The anticorrosion method for steel materials described in this section uses a conductive mortar containing carbon sand as a coating material for coating the coating anticorrosion portion of the steel material. That is, conductivity is imparted to the mortar by adding carbon sand, which is relatively easily available, as a fine aggregate or powder to the mortar, which is one of the commonly used covering materials. At this time, the conductivity of the mortar is adjusted by the amount of carbon sand added or the like. By using such a conductive mortar, the anticorrosion effect of the coated anticorrosion portion of the steel material is enhanced while suppressing the cost.

（３）上記（１）項において、前記被覆材として、導電性を有するコンクリート又はモルタルを用い、前記鋼材の被覆防食部分の周囲を、前記被覆材と複数の鉄筋とを用いた鉄筋コンクリート又はモルタルにより巻き立てる鋼材の防食工法。
本項に記載の鋼材の防食工法は、鋼材の被覆防食部分の周囲を、導電性を有するコンクリート又はモルタルと複数の鉄筋とを用いた、鉄筋コンクリート又はモルタルにより巻き立てることで、鋼材の被覆防食部分の防食効果の向上と同時に、鋼材の補強を図るものである。 (3) In the above item (1), conductive concrete or mortar is used as the covering material, and reinforced concrete or mortar using the covering material and a plurality of reinforcing bars is used around the coated anticorrosion portion of the steel material. anti-corrosion construction method of steel to stand up.
The anticorrosion method for steel materials described in this section is to wind up the periphery of the anticorrosion part covered with steel material with reinforced concrete or mortar using conductive concrete or mortar and a plurality of reinforcing bars. At the same time as improving the anticorrosion effect of mortar, the steel material is reinforced.

（４）電気防食と被覆防食とが併用された鋼材であって、被覆防食部分が導電性を有する被覆材で被覆されていることで、電気防食部分と被覆防食部分との双方に電流が供給される鋼材。
（５）上記（４）項において、前記被覆材として、カーボンサンドを含んだ導電モルタルが用いられ、該導電モルタルは、前記カーボンサンドの添加量が変えられて流入電流密度が試算された試算結果に基づいて、前記カーボンサンドの添加量が調整されている鋼材。
（６）上記（４）項において、被覆防食部分の周囲が、導電性を有するコンクリート又はモルタルと複数の鉄筋とが用いられた、鉄筋コンクリート又はモルタルで巻き立てられている鋼材。
そして、（４）から（６）項の鋼材は、上記（１）から（３）項に記載の鋼材の防食工法によって防食が施されることで、上記（１）から（３）項の鋼材の防食工法に対応する同等の作用を奏するものである。 (4) A steel material in which both electrocorrosion protection and coating anticorrosion are used in combination, and the coating anticorrosion portion is coated with a conductive coating material, so that current is supplied to both the electrocorrosion protection portion and the coating corrosion protection portion. Steel material to be used.
(5) In the above item (4), a conductive mortar containing carbon sand is used as the coating material, and the conductive mortar is a trial calculation result in which the inflow current density is calculated by changing the addition amount of the carbon sand. based on the steel material amount of the carbon sand is adjusted.
(6) In the above item (4), a steel material in which the periphery of the coated anticorrosion portion is wound with reinforced concrete or mortar in which conductive concrete or mortar and a plurality of reinforcing bars are used.
Then, the steel materials of items (4) to (6) are protected from corrosion by the anticorrosion method of the steel materials according to the above items (1) to (3), so that the steel materials of the above items (1) to (3) are protected. It has the same effect as that of the anticorrosion method.

本発明は上記のような構成であるため、電気防食と被覆防食とを併用する鋼材の、被覆防食部分の防食効果を向上することが可能となる。 Since the present invention has the above-described configuration, it is possible to improve the anticorrosion effect of the coating anticorrosion portion of the steel material in which the electrocorrosion protection and the coating anticorrosion are used in combination.

本発明の実施の形態に係る鋼材の防食工法を適用した鋼材を概略的に示すイメージ図である。It is an image figure which shows typically the steel material which applied the anticorrosion method of the steel material which concerns on embodiment of this invention. 図１の鋼材に陽極から供給される電流を概略的に示すイメージ図である。It is an image diagram which shows schematic the electric current which is supplied from the anode to the steel material of FIG. 本発明の実施の形態に係る鋼材の防食工法で用いるための、被覆材の流入電流密度の試算結果を示すグラフである。It is a graph which shows the trial calculation result of the inflow current density of a covering material for use in the anticorrosion method of a steel material which concerns on embodiment of this invention. 従来の防食工法を説明するためのイメージ図である。It is an image figure for demonstrating the conventional anticorrosion method.

以下、本発明を実施するための形態を、添付図面に基づいて説明する。ここで、従来技術と同一部分、若しくは相当する部分については、同一符号で示し、詳しい説明を省略する。
図１は、本発明の実施の形態に係る鋼材の防食工法が適用された鋼材１４を示している。図１の例において、鋼材１４は、海洋構造物１２を支える鋼管杭である。又、鋼材１４は、従来の防食工法（図４参照）と同様に、干満帯から海底土中部までに電気防食が施され、海上大気部から干潮面（ＬＷＬ）−１．０ｍ程度までに被覆防食が施されている。図１の例では、流電陽極方式の電気防食が採用されており、鋼材１４には、陽極１６として、アルミニウムやマグネシウム等の、鋼材１４よりもイオン化傾向の高い金属が接続されている。一方、鋼材１４の被覆防食部分は、導電性を有する被覆材１０で被覆されている。この被覆材１０は、例えば、カーボンサンドの添加によって導電性が付与されたモルタルである。更に、被覆材１０の内部に複数の鉄筋（図示省略）が配置された、鉄筋コンクリート巻き立てになっていてもよい。 Hereinafter, embodiments for carrying out the present invention will be described with reference to the accompanying drawings. Here, the same parts as those in the prior art or the corresponding parts are indicated by the same reference numerals, and detailed description thereof will be omitted.
FIG. 1 shows a steel material 14 to which the anticorrosion method for steel materials according to the embodiment of the present invention is applied. In the example of FIG. 1, the steel material 14 is a steel pipe pile that supports the marine structure 12. Further, the steel material 14 is provided with electrocorrosion protection from the ebb and flow zone to the middle part of the seabed soil as in the conventional anticorrosion method (see FIG. 4), and covers from the sea atmosphere part to the low tide surface (LWL) -1.0 m. It is anticorrosive. In the example of FIG. 1, galvanic anode type electrocorrosion protection is adopted, and a metal having a higher ionization tendency than the steel material 14, such as aluminum or magnesium, is connected to the steel material 14 as the anode 16. On the other hand, the coated anticorrosion portion of the steel material 14 is coated with the conductive coating material 10. The covering material 10 is, for example, a mortar to which conductivity is imparted by adding carbon sand. Further, it may be a reinforced concrete winding in which a plurality of reinforcing bars (not shown) are arranged inside the covering material 10.

ここで、本発明の実施の形態に係る鋼材の防食工法を、電気防食と被覆防食とが併用された既設の鋼材１４に適用する場合について言及する。この場合には、既設の鋼材１４の被覆防食部分において、当該被覆防食部分を被覆していた被覆材を剥がした後、導電性を有する被覆材１０によって、当該被覆防食部分を再び被覆すればよい。これによって、図１に示した鋼材１４と同様の構造が実現される。なお、新設の鋼材１４に対して、本発明の実施の形態に係る鋼材の防食工法を適用する際には、鋼材１４の被覆防食部分を、初めから導電性の被覆材１０によって被覆し、更に、鋼材１４の電気防食部分に電気防食を施せばよい。 Here, a case where the anticorrosion method for steel materials according to the embodiment of the present invention is applied to an existing steel material 14 in which both electrocorrosion protection and coating corrosion protection are applied will be described. In this case, in the coated anticorrosive portion of the existing steel material 14, after the covering material covering the coated anticorrosive portion is peeled off, the coated anticorrosive portion may be again coated with the conductive coating material 10. .. As a result, a structure similar to that of the steel material 14 shown in FIG. 1 is realized. When applying the anticorrosion method for steel materials according to the embodiment of the present invention to the newly installed steel material 14, the coated anticorrosion portion of the steel material 14 is covered with the conductive coating material 10 from the beginning, and further. , The electrocorrosion-proof portion of the steel material 14 may be subjected to electrocorrosion protection.

次に、図２を参照して、本発明の実施の形態に係る鋼材の防食工法が適用された鋼材１４に対して、陽極１６から供給される電流について説明する。図示のように、鋼材１４の海中部には、電気抵抗率が低い海水Ｗが直接触れていることから、比較的大きい電流が陽極１６から供給される。これは、鋼材１４の、電気抵抗率が低い海底土中の部分についても同様である。これに対し、被覆材１０で被覆された、鋼材１４の被覆防食部分は、先に述べたように、ＬＷＬ−１．０ｍ程度まで達している。このため、鋼材１４の被覆防食部分には、海水Ｗと導電性を有する被覆材１０とを介して、海中部や海底土中部よりも小さい電流が陽極１６から供給される。更に、鋼材１４の被覆防食部分へ供給される電流は、被覆材１０と海水Ｗとが接触している部分から離れるに従い、小さくなる。 Next, with reference to FIG. 2, the current supplied from the anode 16 to the steel material 14 to which the anticorrosion method for the steel material according to the embodiment of the present invention is applied will be described. As shown in the figure, since the seawater W having a low electrical resistivity is in direct contact with the submarine portion of the steel material 14, a relatively large current is supplied from the anode 16. This also applies to the portion of the steel material 14 in the seabed soil having a low electrical resistivity. On the other hand, the coated anticorrosion portion of the steel material 14 coated with the covering material 10 reaches about LWL-1.0 m as described above. Therefore, a current smaller than that in the submarine portion or the submarine soil portion is supplied from the anode 16 to the coated anticorrosion portion of the steel material 14 via the seawater W and the conductive covering material 10. Further, the current supplied to the coated anticorrosion portion of the steel material 14 becomes smaller as the distance from the portion where the covering material 10 and the seawater W are in contact increases.

すなわち、陽極１６から供給される電流は、海水Ｗや海底土に直接触れている、腐食速度が大きい傾向にある鋼材１４の海中部や海底土中部に対して、比較的多く供給される。又、腐食環境からの遮断によって腐食速度が小さい傾向にある、鋼材１４の被覆防食部分に対しては、海中部や海底土中部よりも少量の電流が供給され、被覆材１０と海水Ｗとの接触部から離れるにつれて、電流量が小さくなる。しかしながら、飛沫帯や溶存酸素が多い海面直下等の、特に腐食環境が厳しい海面近傍の領域には、被覆材１０と海水Ｗとの接触部が近いため、被覆防食部分の中でも、比較的多くの電流が供給される。 That is, the current supplied from the anode 16 is supplied in a relatively large amount to the submarine portion and the submarine soil portion of the steel material 14 which tends to have a high corrosion rate and is in direct contact with the seawater W and the seabed soil. Further, a smaller amount of current is supplied to the coated anticorrosive portion of the steel material 14 than in the submarine part or the submarine soil part, which tends to have a low corrosion rate due to the interruption from the corrosive environment, and the covering material 10 and the seawater W are supplied with each other. The amount of current decreases as the distance from the contact portion increases. However, since the contact portion between the covering material 10 and the seawater W is close to the region near the sea surface where the corrosive environment is particularly severe, such as a splash zone or just below the sea surface where a large amount of dissolved oxygen is present, a relatively large number of the covering corrosion-proof parts are present. Current is supplied.

続いて、図３には、本発明の実施の形態に係る鋼材の防食工法において被覆材１０として用いる、カーボンサンドを含む導電モルタルの、被覆厚を５ｃｍとした場合の、海面からの距離に応じた流入電流密度の試算結果を示している。流入電流密度の試算は、カーボンサンドの添加量を変えて導電性を異ならせた複数種類の導電モルタルと、カーボンサンドを含まない比較対象としての普通のモルタルとについて行っている。なお、図３のグラフの凡例に記載した２つの値（０−２．０、０．５−１．０等）は、炭素微粉末の粉体置換率−セメント細骨材（カーボン）比（Ｓ／Ｃ）を示しており、Ｎはカーボンサンドを含まない普通のモルタルである。 Subsequently, FIG. 3 shows that the conductive mortar containing carbon sand used as the coating material 10 in the anticorrosion method for steel materials according to the embodiment of the present invention corresponds to the distance from the sea surface when the coating thickness is 5 cm. The calculation result of the inflow current density is shown. The inflow current density is estimated for a plurality of types of conductive mortars in which the amount of carbon sand added is changed to have different conductivity, and an ordinary mortar that does not contain carbon sand and is used as a comparison target. The two values (0-2.0, 0.5-1.0, etc.) described in the legend of the graph of FIG. 3 are the powder substitution rate of carbon fine powder-cement fine aggregate (carbon) ratio (carbon). S / C) is shown, and N is an ordinary mortar containing no carbon sand.

図３から、カーボンサンドを含まない普通のモルタルでは、コンクリート中の鋼材の腐食速度に対抗するための流入電流密度がほとんど得られないことが分かる。これに対し、カーボンサンドを含む導電モルタルの場合は、コンクリート中の鋼材の腐食速度に対抗するための十分な流入電流密度が得られることが分かる。更に、導電モルタルの流入電流密度は、細骨材や紛体としてのカーボンサンドの添加量を変更することで調整されることが分かる。このため、このような試算結果に基づいて、適度な導電性を有する導電モルタルを選定して、本発明の実施の形態に係る鋼材の防食工法で用いる被覆材１０として採用すればよい。 From FIG. 3, it can be seen that with ordinary mortar containing no carbon sand, the inflow current density for countering the corrosion rate of the steel material in concrete can hardly be obtained. On the other hand, in the case of the conductive mortar containing carbon sand, it can be seen that a sufficient inflow current density can be obtained to counter the corrosion rate of the steel material in the concrete. Furthermore, it can be seen that the inflow current density of the conductive mortar can be adjusted by changing the amount of carbon sand added as a fine aggregate or powder. Therefore, based on such a trial calculation result, a conductive mortar having appropriate conductivity may be selected and adopted as the covering material 10 used in the anticorrosion method for steel materials according to the embodiment of the present invention.

さて、上記構成をなす本発明の実施の形態によれば、次のような作用効果を得ることが可能である。すなわち、本発明の実施の形態に係る鋼材の防食工法は、図１に示すように、電気防食と被覆防食とを併用するものであり、鋼材１４の電気防食部分に対して、流電陽極１６を用いた流電陽極方式等で電気防食を施すと共に、鋼材１４の被覆防食部分を、導電性を有する被覆材１０で被覆する。すると、図２に示すように、電気防食のために設置した流電陽極１６から、鋼材１４の電気防食部分だけではなく、鋼材１４の被覆防食部分にも、導電性を有する被覆材１０を介して、電流が供給される。これにより、鋼材１４の被覆防食部分は、被覆材１０によって塩化物イオンや酸素の浸透が抑制されるだけではなく、電流の供給により電位が変化して腐食反応を抑制することができる。従って、鋼材１４の被覆防食部分の防食効果を向上することが可能となる。 Now, according to the embodiment of the present invention having the above configuration, it is possible to obtain the following effects. That is, as shown in FIG. 1, the anticorrosion method for steel materials according to the embodiment of the present invention uses both electrocorrosion protection and coating anticorrosion, and the galvanic anode 16 is applied to the electrocorrosion protection portion of the steel material 14. The galvanic anode method or the like using the above is used to perform electrocorrosion protection, and the coated anticorrosion portion of the steel material 14 is covered with the conductive coating material 10. Then, as shown in FIG. 2, from the galvanic anode 16 installed for electrocorrosion protection, not only the electrocorrosion protection portion of the steel material 14 but also the coating corrosion protection portion of the steel material 14 is passed through the covering material 10 having conductivity. And the current is supplied. As a result, in the coated anticorrosive portion of the steel material 14, not only the permeation of chloride ions and oxygen is suppressed by the coating material 10, but also the potential is changed by the supply of an electric current to suppress the corrosion reaction. Therefore, it is possible to improve the anticorrosion effect of the coated anticorrosion portion of the steel material 14.

又、本発明の実施の形態に係る鋼材の防食工法は、鋼材１４の被覆防食部分を被覆する被覆材１０として、カーボンサンドを含んだ導電モルタルを用いるものである。すなわち、一般的に用いられる被覆材の１つであるモルタルに対して、比較的入手が容易なカーボンサンドを細骨材や粉体として添加することで、モルタルに導電性を付与する。このような導電モルタルを用いることで、コストを抑制しながら、鋼材１４の被覆防食部分の防食効果を高めることができる。更に、導電モルタルの導電性は、図３から確認できるように、カーボンサンド添加量の調整により、コストや強度等とのバランスを考慮しながら、鋼材１４の腐食を抑制するための適切な範囲に調整することが可能である。 Further, in the anticorrosion method for steel materials according to the embodiment of the present invention, a conductive mortar containing carbon sand is used as the coating material 10 for covering the coating anticorrosion portion of the steel material 14. That is, conductivity is imparted to the mortar by adding carbon sand, which is relatively easily available, as a fine aggregate or powder to the mortar, which is one of the commonly used covering materials. By using such a conductive mortar, it is possible to enhance the anticorrosion effect of the coated anticorrosion portion of the steel material 14 while suppressing the cost. Further, as can be confirmed from FIG. 3, the conductivity of the conductive mortar is adjusted to an appropriate range for suppressing corrosion of the steel material 14 while considering the balance with cost, strength, etc. by adjusting the amount of carbon sand added. It is possible to adjust.

又、本発明の実施の形態に係る鋼材の防食工法は、鋼材１４の被覆防食部分の周囲を、導電性を有するコンクリート又はモルタルと複数の鉄筋とを用いた、鉄筋コンクリート又はモルタルにより巻き立てることとすれば、鋼材１４の被覆防食部分の防食効果の向上と同時に、鋼材１４の補強を図ることができる。
更に、本発明の実施の形態に係る鋼材の防食工法を、電気防食と被覆防食とが併用された既設の鋼材１４に対して適用する場合は、鋼材１４の電気防食部分から既設の被覆材を剥がした後、導電性を有する被覆材１０で再び被覆することのみで、施工が完了する。このため、既設の鋼材１４に対しても、容易に適用することができる。 Further, in the anticorrosion method for steel materials according to the embodiment of the present invention, the periphery of the coated anticorrosion portion of the steel material 14 is wound with reinforced concrete or mortar using conductive concrete or mortar and a plurality of reinforcing bars. By doing so, the anticorrosion effect of the coated anticorrosion portion of the steel material 14 can be improved, and at the same time, the steel material 14 can be reinforced.
Further, when the anticorrosion method for a steel material according to the embodiment of the present invention is applied to an existing steel material 14 in which both electrocorrosion protection and coating anticorrosion are used in combination, the existing coating material is applied from the electrocorrosion protection portion of the steel material 14. After peeling off, the construction is completed only by recoating with the conductive coating material 10. Therefore, it can be easily applied to the existing steel material 14.

一方、本発明の実施の形態に係る鋼材１４は、本発明の実施の形態に係る鋼材の防食工法によって防食が施されることで、本発明の実施の形態に係る鋼材の防食工法に対応する上述したような同等の作用効果を奏することができる。
なお、上述した図１や図２の実施例では、流電陽極方式で電気防食を行っているが、電気防食が外部電源方式の場合でも、同様の効果が得られることは、理解されるであろう。 On the other hand, the steel material 14 according to the embodiment of the present invention corresponds to the anticorrosion method for the steel material according to the embodiment of the present invention by being subjected to anticorrosion by the anticorrosion method for the steel material according to the embodiment of the present invention. It is possible to achieve the same effect as described above.
In the examples of FIGS. 1 and 2 described above, the electrocorrosion is performed by the galvanic anode method, but it is understood that the same effect can be obtained even when the electrocorrosion is an external power supply method. There will be.

１０：被覆材、１４：鋼材 10: Coating material, 14: Steel material

Claims (1)

電気防食と被覆防食とを併用する鋼材の防食工法において、
前記鋼材の被覆防食部分を、導電性を有する被覆材で被覆することによって、前記鋼材の電気防食部分と被覆防食部分との双方に電流を供給し、
前記被覆材として、カーボンサンドを含んだ導電モルタルを用い、このとき、前記カーボンサンドの添加量を変えて流入電流密度を試算した前記導電モルタルの試算結果に基づいて、前記導電モルタルへの前記カーボンサンドの添加量を調整することを特徴とする鋼材の防食工法。 In the anti-corrosion method for steel materials that uses both electro-corrosion and coating anti-corrosion.
By coating the coated anticorrosion portion of the steel material with a conductive coating material, an electric current is supplied to both the electrocorrosion-proof portion and the coated anticorrosion portion of the steel material.
A conductive mortar containing carbon sand is used as the coating material, and at this time, the carbon to the conductive mortar is calculated based on the calculation result of the conductive mortar in which the inflow current density is calculated by changing the addition amount of the carbon sand. An anticorrosion method for steel materials, which is characterized by adjusting the amount of sand added.
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