JP4791230B2 - Hydrated cured body having reinforcing bars excellent in neutralization resistance and salt damage resistance and method for producing the same - Google Patents

Description

The present invention is a hydrated and cured body having a reinforcing bar excellent in neutralization resistance and salt damage resistance suitable for use in a structure used in an environment where neutralization and salt damage are likely to proceed, such as coasts where dryness and humidity are repeated And a manufacturing method thereof .

  Reinforced concrete is a structural member that exhibits strength and durability over a long period of time because the passive component film is formed on the surface of the reinforcing bar by the alkali components in the concrete, thereby preventing corrosion of the reinforcing bar. Therefore, when the concrete is neutralized, the passive film is destroyed and the rebar is corroded, so that it does not function as a structural member.

  In recent years, the availability of concrete aggregates has deteriorated, and for example, andesite that may cause an alkali aggregate reaction may be used as an aggregate. When cracks occur in the concrete due to the alkali aggregate reaction, there is a problem that the neutralization of the concrete proceeds rapidly and the reinforcing bars corrode. Even in the case of concrete using high-quality aggregates, if it is used in an environment where neutralization is likely to proceed, such as repeated drying and wetting, the neutralization of the concrete causes the passivation of the reinforcing bar surface. The coating is destroyed and the rebar is corroded, and the concrete is peeled off by volume expansion caused by the generated rust. Naturally, increasing the thickness of the concrete (cover thickness) between the reinforcing bar and the outside world can delay the time for neutralization to reach the surface of the reinforcing bar. There is a problem that the cost increases because the structure becomes larger due to the increase in the size of the structure.

  As a means for improving the neutralization resistance of reinforced concrete as described above, a method of reducing the water-cement ratio is generally known.

  On the other hand, Patent Document 1 and Non-Patent Document 1 disclose a hydrated hardened body that can use steelmaking slag and blast furnace slag fine powder as main raw materials and can replace concrete.

By using these hydrated hardened bodies as a substitute for concrete, it is possible to effectively use slag generated in large quantities at steelworks.
JP 2001-049310 A “Steel Slag Hydrated Solid Technology Manual” Coastal Development Technology Research Center 2003

  However, the method of reducing the water-cement ratio in order to improve the neutralization resistance of reinforced concrete is effective when using high-quality aggregates that do not cause alkali-aggregate reaction, but alkali-aggregate reaction. There is no effect when using aggregates that cause Moreover, if the water-cement ratio is reduced, not only the cost is increased, but also the self-shrinkage of the concrete is increased.

  On the other hand, regarding the neutralization resistance when the hydrated cured body of Patent Document 1 and Non-Patent Document 1 is used as a concrete substitute, the hydrated cured body disclosed in Patent Document 1 is used for roadbed materials, The hydration hardened body disclosed in Non-Patent Document 1 is unclear to the extent that it is used for construction and earthwork, etc., and the target is limited to the replacement of unreinforced concrete that does not contain reinforcing bars. Is unknown. Then, when the present inventors investigated the neutralization resistance of these hydrated cured bodies, it was found that the dispersion was extremely large and it was difficult to stably use as a substitute for reinforced concrete.

  As described above, there is a limit to prevent corrosion of reinforcing bars by suppressing neutralization of a hydrated and hardened body made of concrete, steelmaking slag, blast furnace slag fine powder, or the like using conventional techniques.

Therefore, the object of the present invention is to solve the problems of the prior art, and to make the structure member having long-term durability even under environmental conditions where neutralization is likely to proceed, An object of the present invention is to provide a hydrated cured product having a reinforcing bar excellent in salt damage resistance and a method for producing the same.

The features of the present invention for solving such problems are as follows.
(1) A hydrated hardened body having a reinforcing bar in its interior comprises steelmaking slag, blast furnace slag fine powder, and fly ash having a CaO / SiO ₂ ratio of less than 1.5 and a CaO concentration of less than 25% by mass. And the content of the fly ash is 100 kg / m ³ or more, and the hydrated cured product is a B-type blast furnace cement, JIS R 5213 “fly ash”, which is further compatible with Portland cement, JIS R 5211 “blast furnace cement”. B type fly ash cement suitable for “cement”, containing one or more selected from slaked lime, the content of which is [Portland cement (kg / m ³ ) + blast furnace cement (kg / m ³ ) × 0 .6Tasu fly ash cement ^{(kg / m 3) × 0.85} + slaked lime ^{(kg / m 3)] /} [ fly ash (kg / m ³⁾ + Furaia' Yusemento ^{× 0.15 (kg / m 3)} ] in is 0.45 or less, and the content of the steel slag is at 1975kg / m ³ or more, and, blast furnace slag derived from blast furnace cement in the mixture Content of blast furnace slag fine powder other than fine powder is 100 kg / m ³ or more, and the reinforcing bar has an oxide layer containing Fe, P, and V on its surface. Hydrated hardened body with rebars with excellent salt damage.
(2) A hydrated and cured body having a reinforcing bar in its interior comprises steelmaking slag, blast furnace slag fine powder, and fly ash having a CaO / SiO ₂ ratio of less than 1.5 and a CaO concentration of less than 25% by mass. And the content of the fly ash is 100 kg / m ³ or more, and the hydrated cured product is a B-type blast furnace cement, JIS R 5213 “fly ash”, which is further compatible with Portland cement, JIS R 5211 “blast furnace cement”. B type fly ash cement suitable for “cement”, containing one or more selected from slaked lime, the content of which is [Portland cement (kg / m ³ ) + blast furnace cement (kg / m ³ ) × 0 .6Tasu fly ash cement ^{(kg / m 3) × 0.85} + slaked lime ^{(kg / m 3)] /} [ fly ash (kg / m ³⁾ + Furaia' Yusemento ^{× 0.15 (kg / m 3)} ] in is 0.45 or less, and the content of the steel slag is at 1975kg / m ³ or more, and, blast furnace slag derived from blast furnace cement in the mixture Reinforcing bar excellent in neutralization resistance and salt damage resistance, characterized in that the content of fine powder of blast furnace slag other than fine powder is 100 kg / m ³ or more and the reinforcing bar has a silane coupling agent layer on the surface Hydrated cured body having
(3) A silane coupling agent layer is further laminated on a reinforcing bar having an oxide layer containing Fe, P, and V on the surface, and the neutralization resistance and anti-resistance described in (2) Hydrated hardened body with rebars with excellent salt damage.
(4) The reinforcing bar is coated with a treatment solution containing H ₃ PO ₄ : _{2 to} 15 mol / l and V ₂ O ₅ : 0.1 to 300 g / l on the surface of the reinforcing bar, washed and dried, and further silane coupling Agent: Reinforcing bar in which an oxide layer obtained by heating at 60 to 200 ° C. and a silane coupling agent layer are laminated after applying and washing a treatment liquid containing 0.1 to 2 mass%. A hydrated cured product having a reinforcing bar excellent in neutralization resistance and salt damage resistance as described in (3).
(5) to the silane coupling agent (2) no, characterized in that an amino-based silane coupling agent excellent rebar耐中resistance resistance and salt damage resistance according to any one of (4) Hydrated cured product.
(6) A method for producing a hydrated cured body having a reinforcing bar excellent in neutralization resistance and salt damage resistance, [Portland cement (kg / m ³ ) + blast furnace cement (kg / m ³ ) × 0. 6 + fly ash cement (kg / m ³ ) × 0.85 + slaked lime (kg / m ³ )] / [fly ash (kg / m ³ ) + fly ash cement × 0.15 (kg / m ³ )] It is selected from at least Portland cement, Type B blast furnace cement compatible with JIS R 5211 “Blast furnace cement”, Type B fly ash cement compatible with JIS R 5213 “Fly ash cement”, and slaked lime so as to be 45 or less. and one or more, less than 1.5 at CaO / SiO ₂ mass ratio, and, the steelmaking slag CaO concentration is less than 25 wt%, and blast furnace slag, fly A Mesh is mixed with water, comprising the step of curing the resulting mixture, the content of the fly ash is not more 100 kg / m ³ or more and the content of the steelmaking slag be 1975kg / m ³ or more And the content of the blast furnace slag fine powder other than the blast furnace slag fine powder derived from the blast furnace cement in the mixture is 100 kg / m ³ or more, and the reinforcing bar has Fe, P, and V on its surface. A method for producing a hydrated cured product having a reinforcing bar excellent in neutralization resistance and salt damage resistance, characterized by comprising:
(7) A method for producing a hydrated cured product having a reinforcing bar excellent in neutralization resistance and salt damage resistance, wherein [Portland cement (kg / m ³ ) + blast furnace cement (kg / m ³ ) × 0. 6 + fly ash cement (kg / m ³ ) × 0.85 + slaked lime (kg / m ³ )] / [fly ash (kg / m ³ ) + fly ash cement × 0.15 (kg / m ³ )] It is selected from at least Portland cement, Type B blast furnace cement compatible with JIS R 5211 “Blast furnace cement”, Type B fly ash cement compatible with JIS R 5213 “Fly ash cement”, and slaked lime so as to be 45 or less. and one or more, less than 1.5 at CaO / SiO ₂ mass ratio, and, the steelmaking slag CaO concentration is less than 25 wt%, and blast furnace slag, fly A Mesh is mixed with water, comprising the step of curing the resulting mixture, the content of the fly ash is not more 100 kg / m ³ or more and the content of the steelmaking slag be 1975kg / m ³ or more The content of fine blast furnace slag powder other than fine blast furnace slag powder derived from blast furnace cement in the mixture is 100 kg / m ³ or more, and the reinforcing bar has a silane coupling agent layer on the surface. A method for producing a hydrated cured body having a reinforcing bar excellent in neutralization resistance and salt damage resistance.

  According to the present invention, since it is excellent in neutralization resistance and salt damage resistance, a hydrated cured product having excellent anticorrosive properties against reinforcing steel can be obtained. For this reason, the structure which can be used for a long period of time can be provided even in the environment where the conventional reinforced concrete collapses in a short period of time by neutralization.

  In the present invention, by optimizing the material of the hydrated hardened body, the hydration hardening having better neutralization resistance than conventional hydrated hardened bodies made of concrete, steelmaking slag and blast furnace slag fine powder, etc. As a structural member that has a long-term durability even in an environment where neutralization and salt damage are likely to occur due to the combination of high salinity and repeated drying and wetting, by combining this with a surface-treated steel bar The present invention has been completed by finding that it can be used.

  First, materials constituting the hydrated cured body will be described.

  In the present invention, the content (in the hydrated cured body) (in the hydrated cured body) of the hydrated cured body includes each material (including kneading water and admixture) that is a raw material for blending the hydrated cured body. ) In the mixed mixture. The hydrated cured product in the present invention is obtained by curing a mixture formed by mixing materials to be blended raw materials.

  The hydrated cured product of the present invention contains steelmaking slag, blast furnace slag fine powder, and fly ash.

Among the materials of the hydrated hardened body, the steelmaking slag acts as an aggregate and a binder, and further as a neutralization inhibitor for the hydrated hardened body. The particle size distribution of the steelmaking slag for acting as an aggregate is a particle size corresponding to fine aggregate or coarse aggregate for concrete, the particle size is about 0.075 mm or more, and the maximum particle size is about 40 mm or less. It is preferable to do. Moreover, it is preferable that the steelmaking slag for making it act as a binder is a fine powder, and it is preferable that a particle size is less than about 0.15 mm. Accordingly, a steelmaking slag having an appropriate particle size distribution containing slag particles satisfying the particle size as a binder and the particle size as an aggregate (for example, steelmaking slag pulverized under a certain condition and its pulverization treatment). It is desirable to use steelmaking slag that is sieved later. The steelmaking slag for acting as a neutralization inhibiting material preferably has a CaO / SiO ₂ ratio of 1.5 or more, or a CaO concentration of 25% by mass or more. CaO / SiO ₂ is in a weight ratio of 1.5 or more, or CaO concentration of 25 mass% or more steel slag is dissolved in water CaO component in the steelmaking slag is contained in the hydrated cured body over a long period of time, water Keep the Japanese cured body weakly alkaline and suppress neutralization. More preferably, CaO / SiO ₂ is 2.0 or more by mass ratio, or the CaO concentration is 30% by mass or more. Generally, when the CaO / SiO ₂ and CaO concentrations are increased, the hydration expansion due to free CaO (free-CaO) in the steelmaking slag increases, but there is no problem if the expansion stability of the hydrated cured body is ensured. These upper limits are not specified.

  In addition, steelmaking slag does not cause an alkali-aggregate reaction unlike ordinary gravel aggregates, so that not only the durability of the hydrated hardened body itself is excellent, but also the occurrence of cracks due to the alkali-aggregate reaction can be suppressed. Therefore, neutralization through cracks does not occur, which is preferable from the viewpoint of corrosion prevention of reinforcing steel in the hydrated cured body.

  The reason why blast furnace slag fine powder is used as a material for the hydrated hardened body is not only because the blast furnace slag fine powder having latent hydraulic properties is subjected to alkali stimulation by steelmaking slag and efficiently hydrates but also more than conventional concrete. This is because, since the cured product has a dense structure, the permeation of carbon dioxide that causes neutralization of the hydrated cured product can be remarkably suppressed. Moreover, it is because the free blast furnace slag fine powder and free CaO (free-CaO) in the steelmaking slag react to suppress the hydration expansion of the steelmaking slag. As the blast furnace slag fine powder, JIS A 6206 “Blast furnace slag fine powder for concrete” can be particularly preferably used.

The blending amount of the blast furnace slag fine powder in the hydrated cured product is preferably 100 to 600 kg / m ³ . If it is less than 100 kg / m ³ , the compressive strength of 18 N / mm ² or more necessary as a concrete substitute may not be obtained, and if it exceeds 600 kg / m ³ , there is almost no increase in strength and it becomes uneconomical. A more preferable blending amount of the blast furnace slag fine powder is 200 to 400 kg / m ³ .

The fly ash is used as the material of the hydrated cured body because the fly ash having pozzolanic reactivity reacts with steelmaking slag and blast furnace slag fine powder for a long time, and the generated hydrated gel fills the voids in the structure. This is because the cured product has an extremely dense structure as compared with conventional concrete and can significantly suppress the permeation of carbon dioxide which causes neutralization of the hydrated cured body. For this purpose, it is necessary to contain 100 kg / m ³ or more of fly ash. By setting the fly ash to 100 kg / m ³ , the average pore diameter is about 0.1 μm for ordinary concrete, whereas it becomes about 0.01 μm and about 1/10 for the hydrated cured product of the present invention. Further, fly ash has an effect of suppressing hydration expansion of steel slag by reacting fly ash with free CaO in the steel slag. The upper limit of fly ash is not particularly set, but if it exceeds 300 kg / m ³ , the viscosity of a fresh state after adding water and kneading becomes high, and workability deteriorates. Moreover, the effect which suppresses the hydration expansion | swelling of steelmaking slag is also uneconomical. As fly ash, JIS A 6201 “Fly Ash for Concrete” is preferably used, but raw powder, pressurized fluidized bed ash and the like can also be used.

As a material for the hydrated cured body, one or more selected from Portland cement, blast furnace cement, fly ash cement, eco cement and slaked lime are preferably added. Portland cement, blast furnace cement, fly ash cement, eco The content of one or more selected from cement and slaked lime is [Portland cement (kg / m ³ ) + blast furnace cement (kg / m ³ ) × 0.6 + fly ash cement (kg / m ³ ) × 0. 85 + slaked lime (kg / m ³ )] / [fly ash (kg / m ³ ) + fly ash cement × 0.15 (kg / m ³ )] is preferably 0.45 or less. By adding these cements containing calcium components and slaked lime, the pozzolanic reaction of fly ash occurs efficiently, and the average pore diameter becomes about 0.01 μm in one month after the formation of the hydrated cured body, and the structure becomes dense in a short period of time. It is because it can be made. That is, the penetration and permeation of carbon dioxide gas and water vapor that cause neutralization of the hydrated cured product can be remarkably suppressed. From such a viewpoint, [Portland cement (kg / m ³ ) + blast furnace cement (kg / m ³ ) × 0.6 + fly ash cement (kg / m ³ ) × 0.85 + slaked lime (kg / m ³ )] / The value of [fly ash (kg / m ³ ) + fly ash cement × 0.15 (kg / m ³ )] is preferably 0.45 or less, and more preferably 0.40 or less. Although the lower limit is not particularly provided, it is preferable that the lower limit is 0.15 or more because the above-described effect can be obtained.

  The Portland cement in the present invention is described in JIS R 5210 “Portland cement”, ordinary Portland cement, early-strength Portland cement, super-early-strength Portland cement, moderately hot Portland cement, low heat Portland cement, sulfate resistant salt Portland cement. Further, the blast furnace cement is A type, B type or C type described in JIS R 5211 “Blast furnace cement”. Moreover, fly ash cement is A class, B class, and C class as described in JIS R 5213 “fly ash cement”. Ecocement is JIS R 5214 “Ecocement”.

  Next, the reinforcing bars used in the present invention will be described. In addition, the non-muscle hydrated cured product does not cause a problem even when the resistance to neutralization is not excellent.

  The reinforcing bar which the hydration hardening body of this invention has in the inside is a reinforcing bar which has an oxide layer containing Fe, P, and V on the surface, or a reinforcing bar which has a silane coupling agent layer on the surface. It is preferable that a silane coupling agent layer is further laminated on a reinforcing bar having an oxide layer containing Fe, P, and V on the surface.

When laminating an oxide layer and a silane coupling agent layer on the surface of the reinforcing bar, a treatment containing H ₃ PO ₄ : _{2 to} 15 mol / l and V ₂ O ₅ : 0.1 to 300 g / l on the surface of the reinforcing bar It is desirable to manufacture by heating the rebar at 60 to 200 ° C. after applying and washing the solution and drying, and further applying and washing a treatment solution containing a silane coupling agent: 0.1 to 2 mass%. The silane coupling agent is preferably an amino silane coupling agent.

  In many cases, corrosion of reinforcing bars in the hydrated cured body occurs at the interface between the hydrated cured body and the reinforcing bars. This is because the hydrated hardened body is not a complete barrier layer, so water, oxygen, ions, etc. that penetrate from the outside and diffuse the hydrated hardened body over a long period of time are the interface between the hydrated hardened body and the reinforcing bar surface. As a result, the adhesive bond between the reinforcing bar surface (or the treatment layer on the surface) and the hydrated hardened body is broken, and the corrosion reaction occurs on the reinforcing bar surface. Therefore, first of all, the surface of the reinforcing bar is protected by the surface treatment layer, and a strong bond that cannot be easily broken at the interface between the hydrated hardened body and the reinforcing bar surface can improve end face peel resistance and secondary adhesion. Leads to.

  Therefore, in the present invention, an oxide layer containing Fe, P, and V or a silane coupling agent layer is formed on the surface of the reinforcing bar. Particularly preferably, a surface treatment layer is laminated in the order of an oxide layer containing Fe, P and V and a silane coupling agent layer on the surface of the reinforcing bar, and the hydrated cured body and the reinforcing bar are bonded through this surface treatment layer. Let

First, an oxide layer containing Fe, P and V will be described. This oxide layer is a film obtained by applying a treatment liquid to which H ₃ PO ₄ and V ₂ O ₅ are added to the surface of the reinforcing bar, and has the following effects.

That is, H ₃ PO ₄ etches the rebar surface and generates an extremely thin oxide layer on the rebar surface. On the other hand, V ₂ O ₅ forms a complex with phosphoric acid or dissolves alone, and vanadium is adsorbed on the surface of the reinforcing bar, thereby deactivating the surface. An oxide layer grows on the surface of the reinforcing bar by balancing the functions of the two. In this growth process, phosphoric acid, vanadium complex, or vanadium is incorporated into the oxide film, and an oxide containing Fe, P, and V A layer is formed.

  Although this oxide layer is very thin, it becomes a strong and non-conductive oxide film on the surface of the reinforcing bar, and has a function of reducing the sensitivity of the reinforcing bar to corrosion.

Here, if the H ₃ PO ₄ addition concentration in the treatment liquid used for forming the oxide layer is less than 2 mol / l, a sufficient etching effect cannot be obtained. Therefore, the etching does not proceed, so that the H ₃ PO ₄ addition concentration needs to be regulated in the range of 2 to 15 mol / l.

V ₂ O ₅ is a poorly water-soluble oxide, and its dissolved amount increases in aqueous solution due to a decrease or increase in pH. Since the effect is higher as the amount of V ₂ O ₅ dissolved is larger, it is preferable to add it until it is saturated. Specifically, it is necessary to add it at 0.1 to 300 g / l. That is, when the addition concentration of V ₂ O ₅ is less than 0.1 g / l, the amount of vanadium that is adsorbed on the surface of the reinforcing bar or taken into the oxide layer does not reach a sufficient effect, whereas when it exceeds 300 g / l, Since the amount of V ₂ O ₅ is exceeded, the amount of vanadium adsorbed on the surface of the reinforcing bar or taken into the oxide layer is saturated as a result, and no further effect can be expected. Furthermore, a sufficient oxide layer cannot be obtained, and the performance deteriorates.

  In addition, when making said processing liquid adhere to a reinforcing bar surface, the processing time in particular is not prescribed | regulated, However, Preferably it is between 30 seconds-300 seconds. That is, if the treatment time is too short, an oxide layer is not generated, and if it is too long, an unstable oxide layer is generated. Furthermore, it is necessary to wash the surface of the reinforcing bars after a suitable treatment time after the treatment liquid adheres (washed with water), in order to remove excess phosphoric acid and vanadium that have not been taken into the oxide layer. . Without this cleaning, phosphoric acid and vanadium remaining on the surface of the reinforcing bars will form an unstable layer at the interface, and thus it is necessary to remove them by cleaning. After washing, dry to remove washing water and the like.

  Next, the silane coupling agent layer will be described. The silane coupling agent is effective in improving the adhesion between the reinforcing bar and the hydrated solid body. In addition, since the above oxide film has few polar groups useful for adhesion, the above oxide layer is treated with a silane coupling agent treatment solution, which is effective for adhesion with a hydrated cured body and has a binding energy. A high silane coupling agent layer can be formed to compensate for insufficient adhesion.

  The silane coupling agent is preferably an amino silane coupling agent. Particularly suitable for formation on the oxide layer is an amino-based silane coupling agent. This is because the amino silane coupling agent has an amine, and this amine part is highly reactive with the OH group on the oxide layer and the polar group (glycidyl group, hydroxyl group, carboxyl group, etc.) in the hydrated cured product, This is because the binding energy is also high. The same applies to silanol groups in silane coupling agents. When amino-based silane coupling agents are used, stable adhesion can be obtained regardless of which polar part of amine or silanol group is adsorbed to the oxide layer. is there. Moreover, among silane coupling agents, it is because the stability in a solution is high and it is easy to use it.

  When a silane coupling agent layer is provided on the oxide layer, the silane coupling agent layer is a solution containing the silane coupling agent: 0.1 to 2 mass% in the reinforcing bar on which the oxide layer is formed. It is formed by heating the rebar to a temperature range of 60 to 200 ° C. after washing. First, if the amount of silane coupling agent dissolved is less than 0.1 mass%, the silane coupling agent adsorbed after adhesion is reduced and the desired effect cannot be obtained. On the other hand, if it exceeds 2 mass%, the solution stability is improved by self-condensation. Degradation, that is, silane coupling agent molecules are self-condensed, resulting in multimers such as dimers and trimers, and precipitation or gelation occurs in the liquid. Furthermore, since the molecular weight is increased, adsorption inhibition on the oxide layer occurs and proper treatment cannot be performed, so the content is limited to 0.1 to 2 mass%.

  Here, as a solvent of the solution containing the silane coupling agent, one obtained by adding one or more of acetic acid aqueous solution, hydrochloric acid aqueous solution and nitric acid aqueous solution to pure water, or further adding ethanol is suitable. This is because silane coupling agents have a problem of stability due to dealcoholization reaction and silanol group self-condensation reaction in a solvent. That is, the self-condensation reaction rate of the silanol group and the average molecular weight finally stabilized depend on the pH in the solution. This is due to the structure of the silane coupling agent, and an optimum pH range (mainly in the acidic range) exists depending on the structure. Since it is necessary to control the solvent in this pH range, it is preferable to control with an acid solution. In addition, ethanol is preferably added to improve the wettability of the surface when applied to the reinforcing bar, or to suppress this when the self-condensation reaction is very fast even in the optimum pH range.

  After adhering the above solution to the reinforcing bar, it is necessary to take time for the silane coupling agent in the solution to be adsorbed on the oxide layer side, and this time is preferably about 5 to 300 seconds. . Furthermore, it is necessary to wash (wash with water) in the same manner as in the previous treatment, but this is to remove the unreacted silane coupling agent. If there is no washing treatment, the unreacted coupling agent remains. An unstable interface is formed.

  Next, the temperature of the reinforcing bars for baking and drying was limited to 60 to 200 ° C. The silanol groups were present adsorbed on the surface of the oxide layer, and when heated, the silanol groups and the hydroxyl groups on the oxide surface This is because dehydration condensation occurs and bonds become stronger. That is, when the heating temperature is less than 60 ° C., this effect is not remarkable, whereas when it exceeds 200 ° C., a part of the silane coupling agent is decomposed. Preferably, it is set as the range of 80-120 degreeC.

  Silane coupling agents include γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, bis (triethoxysilylpropyl) tetraamine, bis (trimethoxysilylpropyl) tetraamine, and N-2 (aminoethyl). 3-aminopropylmethyldimethoxysilane, N-2 (aminoethyl) 3-aminopropyltrimethoxysilane, N-2 (aminoethyl) 3-aminopropyltriethoxysilane, 3-triethoxysilyl-N- (1.3 -Dimethyl-butylidene) propylamine, amino-based silane coupling agents such as N-phenyl-3-aminopropyltrimethoxysilane, epoxy-based silane coupling agents such as 3-glycidoxypropylmethylethoxysilane, or 3- Mercaptopropyltriet Mercapto-based silane coupling agents such as xysilane can be used.

  The hydrated cured body is produced by blending the above materials, adding water, kneading, and driving and curing in a predetermined formwork or the like. Reinforcing the reinforcing bars that have been subjected to the above-mentioned surface treatment at the time of driving into a hydrated and cured body having reinforcing bars.

  As a curing method for the hydrated cured body, any method such as underwater curing, on-site curing, and steam curing that are usually used in concrete can be used as long as a predetermined strength can be secured.

Steelmaking slags having the chemical components and physical properties shown in Table 1 (maximum particle diameter, coarse particle ratio, fine aggregate ratio, surface dry density) were used (steelmaking slag Nos. A and B). It is a steelmaking slag that has a CaO / SiO ₂ mass ratio of less than 1.5 and a CaO concentration of less than 25% by mass and is unlikely to act as a neutralization inhibitor.

  The coarse particle ratio is the coarse particle ratio of No. 3115 described in JIS A 0203. The fine aggregate rate is a value representing the absolute volume ratio of the amount of steelmaking slag having a particle size of 5 mm or less with respect to the amount of steelmaking slag of all particle sizes as a percentage.

  The surface treatment of the reinforcing bars was performed as follows.

0.05 to 320 g / l of V ₂ O ₅ was added to various concentrations of H ₃ PO ₄ aqueous solution and stirred at 25 ° C. for 172 hours to prepare various treatment solutions. Each of the prepared treatment liquids was applied to the surface of a reinforcing bar (25φ × 200 mm) blasted with a steel grid, allowed to stand for 2 minutes, washed with pure water, and dried with hot air at 60 ° C.

Thereafter, γ-aminopropyl triethoxysilane (silane coupling agent: SC-A) was dissolved in pure water (solvent) at various concentrations of 0.05 to 2.5 mass% and stirred with a magnetic stirrer for 60 minutes. Then, bis (triethoxysilylpropyl) tetraamine (silane coupling agent: SC-B) is dissolved at various concentrations in a solvent obtained by adding 10 mass% ethanol to 0.5 mass% acetic acid aqueous solution, and stirred with a magnetic stirrer for 120 minutes. 3-glycidoxypropyltriethoxysilane (silane coupling agent: SC-C) at various concentrations of 0.5 and 2.0 mass% in a 0.5 mass% acetic acid aqueous solution and stirred with a magnetic stirrer for 120 minutes The solution was applied to the surface of the rebar previously treated and allowed to stand for 2 minutes. Then, the surface was washed with the same solvent in which the silane coupling agent was dissolved, and heated in an electric furnace set at 110 ° C until the rebar surface temperature reached 100 ° C (the temperature was changed for some rebars) ( Surface treatment Nos. 1 to 18, with No. 17 being no oxide layer and No. 18 being neither an oxide layer nor an SC agent layer). Table 2 shows the phosphoric acid addition concentration, V ₂ O ₅ addition concentration, SC agent type, SC agent addition amount, and heating temperature in each surface treatment.

  According to the composition shown in Table 3 (Formulation Nos. 1 to 11), the hydrated cured material was kneaded with a mixer, poured into a mold of φ100 × 200 mm, cured, and no. Test pieces for measuring the compressive strength of 1 to 21 were produced.

  Blast furnace slag fine powder used was blast furnace slag fine powder 4000 in JIS A 6206 “Blast furnace slag fine powder for concrete”, and fly ash used type II in JIS A 6201 “Fly ash for concrete”. As the Portland cement, ordinary Portland cement conforming to JIS R 5201 “Portland cement” was used. As the blast furnace cement, type B suitable for JIS R 5211 “blast furnace cement” was used. As the fly ash cement, type B conforming to JIS R 5213 “fly ash cement” was used. As the slaked lime, industrial slaked lime / special name conforming to JIS R 9001 was used. As the admixture, a polycarboxylic acid-based high-performance AE water reducing agent conforming to JIS A 6204 was used.

The compressive strength was measured in accordance with JIS A 1108 “Concrete compressive strength test method”. The curing conditions were standard curing 28 days. At the same time, a test piece for a neutralization promotion test of φ100 × 200 mm in which a reinforcing bar subjected to the surface treatment shown in Table 2 was inserted at the center was No. Two pieces were manufactured according to each manufacturing condition of 1-21. The curing conditions were standard curing 28 days. The neutralization promotion test is a test piece that was exposed to a test piece after 28 days of standard curing for 91 days under conditions of CO ₂ concentration 5%, temperature 40 ° C, and humidity 60% RH. The chemical depth was measured and evaluated from the average value. The neutralization depth was measured by using a phenolphthalein 1% solution spray method and setting the non-colored portion to the neutralized portion.

  Of the specimens that had been subjected to the neutralization promotion test, those that were not cut into pieces were subjected to a salt damage resistance test. In the salt damage resistance test, one cycle consists of immersing in a 3% NaCl aqueous solution at 60 ° C. for 3 days and then drying in a constant temperature and humidity bath at 60 ° C. and 50% RH for one cycle. The hardened body was destroyed and the rebar was taken out. The rebar was derusted with a 10 mass% aqueous solution of ammonium hydrogen citrate, and the corrosion area ratio and the maximum corrosion depth were measured with a micrometer.

  For comparison, a test piece (No. 22) of ordinary concrete that does not use steelmaking slag and blast furnace slag fine powder was prepared. According to the composition shown in Table 4, concrete materials were mixed with a mixer, poured into a φ100 × 200 mm mold, and cured to produce test pieces for compressive strength measurement, neutralization promotion test, and salt damage resistance test. . The curing conditions for the test pieces for compressive strength measurement were standard curing 28 days. The compressive strength test, neutralization acceleration test, and salt damage resistance test were performed in the same manner as described above. The aggregate used was a high-quality one determined to be “harmless” in the test according to JIS A 1145 “Aggregate Alkali Silica Reactivity Test Method (Chemical Method)”.

The compression strength measurement results, neutralization promotion test results, and salt damage resistance test results are also shown in Tables 3 and 4. When steelmaking slag, blast furnace slag fine powder and fly ash are contained, and a hydrated hardened body containing fly ash at 100 kg / m ³ or more and a reinforcing bar having a predetermined steel composition are combined (test pieces No. 1 to 17) The test piece No. with a water cement ratio (water binder ratio) of 50% using high-quality aggregates. The neutralization depth was smaller than that of ordinary concrete No. 22 (formulation No. 12), and excellent neutralization resistance was exhibited. On the other hand, the comparative hydrated cured body (test pieces No. 18 to 21) outside the scope of the present invention is more resistant than ordinary concrete (test piece No. 22) having a water cement ratio of 50% using a high-quality aggregate. It was inferior in neutralization property, and corrosion of the reinforcing bars was observed after the salt damage resistance test.

Claims (7)

The hydrated cured body having a reinforcing bar inside contains at least CaO / SiO ₂ in a mass ratio of less than 1.5 and a steelmaking slag having a CaO concentration of less than 25% by mass , blast furnace slag fine powder, and fly ash, The content of the fly ash is 100 kg / m ³ or more, and the hydrated hardened body is further converted into JIS R 5213 “fly ash cement”, a Type B blast furnace cement suitable for Portland cement, JIS R 5211 “blast furnace cement”. Containing one or more types selected from B-type fly ash cement and slaked lime, the content of which is [Portland cement (kg / m ³ ) + blast furnace cement (kg / m ³ ) × 0.6 + fly ash cement ^{(kg / m 3) × 0.85} + slaked lime ^{(kg / m 3)] /} [ fly ash (kg / m ³⁾ + fly ash Se Cement ^{× 0.15 (kg / m 3)} ] in is 0.45 or less, and the content of the steel slag is at 1975kg / m ³ or more, and, blast furnace slag derived from blast furnace cement in the mixture The content of blast furnace slag fine powder other than fine powder is 100 kg / m ³ or more, and the reinforcing bar has an oxide layer containing Fe, P, and V on its surface. Hydrated hardened body with rebars with excellent salt damage. The hydrated cured body having a reinforcing bar inside contains at least CaO / SiO ₂ in a mass ratio of less than 1.5 and a steelmaking slag having a CaO concentration of less than 25% by mass , blast furnace slag fine powder, and fly ash, The content of the fly ash is 100 kg / m ³ or more, and the hydrated hardened body is further converted into JIS R 5213 “fly ash cement”, a Type B blast furnace cement suitable for Portland cement, JIS R 5211 “blast furnace cement”. Containing one or more types selected from B-type fly ash cement and slaked lime, the content of which is [Portland cement (kg / m ³ ) + blast furnace cement (kg / m ³ ) × 0.6 + fly ash cement ^{(kg / m 3) × 0.85} + slaked lime ^{(kg / m 3)] /} [ fly ash (kg / m ³⁾ + fly ash Se Cement ^{× 0.15 (kg / m 3)} ] in is 0.45 or less, and the content of the steel slag is at 1975kg / m ³ or more, and, blast furnace slag derived from blast furnace cement in the mixture Reinforcing bar excellent in neutralization resistance and salt damage resistance, characterized in that the content of fine powder of blast furnace slag other than fine powder is 100 kg / m ³ or more and the reinforcing bar has a silane coupling agent layer on the surface Hydrated cured body having   The neutralization resistance and salt damage resistance according to claim 2, wherein a silane coupling agent layer is further laminated on a reinforcing bar having an oxide layer containing Fe, P, and V on the surface. Hydrated hardened body with excellent reinforcing bars. The reinforcing bar was coated with a treatment solution containing H ₃ PO ₄ : _{2 to} 15 mol / l and V ₂ O ₅ : 0.1 to 300 g / l on the surface of the reinforcing bar, washed and dried, and further a silane coupling agent: 0.1 4. A reinforcing bar obtained by laminating an oxide layer and a silane coupling agent layer obtained by heating at 60 to 200 ° C. after applying and washing a treatment liquid containing ˜2 mass%. A hydrated cured product having a reinforcing bar excellent in neutralization resistance and salt damage resistance described in 1. Hydrated with耐中resistance resistance and salt damage excellent in reinforcing bars according to any one of claims 2 to 4, wherein the silane coupling agent is an amino silane coupling agent Cured body. A method for producing a hydrated cured body having a reinforcing bar excellent in neutralization resistance and salt damage resistance, comprising [Portland cement (kg / m ^Three ) + Blast furnace cement (kg / m ^Three ) X 0.6 + fly ash cement (kg / m ^Three ) X 0.85 + slaked lime (kg / m ^Three )] / [Fly ash (kg / m ^Three ) + Fly ash cement × 0.15 (kg / m ^Three )], At least Portland cement, Class B blast furnace cement suitable for JIS R 5211 “Blast Furnace Cement”, Class B fly ash cement suitable for JIS R 5213 “Fly Ash Cement” One or more selected from slaked lime and CaO / SiO ₂ A steelmaking slag having a mass ratio of less than 1.5 and a CaO concentration of less than 25% by mass, blast furnace slag fine powder and fly ash are mixed with water, and the resulting mixture is cured, The fly ash content is 100 kg / m ^Three And the steelmaking slag content is 1975 kg / m. ^Three The content of the blast furnace slag fine powder other than the blast furnace slag fine powder derived from the blast furnace cement in the mixture is 100 kg / m. ^Three It is the above, The manufacturing method of the hydration hardening body which has a reinforcing bar excellent in neutralization resistance and salt damage resistance characterized by the above-mentioned. A method for producing a hydrated cured body having a reinforcing bar excellent in neutralization resistance and salt damage resistance, comprising [Portland cement (kg / m ^Three ) + Blast furnace cement (kg / m ^Three ) X 0.6 + fly ash cement (kg / m ^Three ) X 0.85 + slaked lime (kg / m ^Three )] / [Fly ash (kg / m ^Three ) + Fly ash cement × 0.15 (kg / m ^Three )], At least Portland cement, Class B blast furnace cement suitable for JIS R 5211 “Blast Furnace Cement”, Class B fly ash cement suitable for JIS R 5213 “Fly Ash Cement” One or more selected from slaked lime and CaO / SiO ₂ A steelmaking slag having a mass ratio of less than 1.5 and a CaO concentration of less than 25% by mass, blast furnace slag fine powder and fly ash are mixed with water, and the resulting mixture is cured, The fly ash content is 100 kg / m ^Three And the steelmaking slag content is 1975 kg / m. ^Three The content of the blast furnace slag fine powder other than the blast furnace slag fine powder derived from the blast furnace cement in the mixture is 100 kg / m. ^Three It is the above, The manufacturing method of the hydration hardening body which has a reinforcing bar excellent in neutralization resistance and salt-damage resistance characterized by the above-mentioned reinforcing steel having a silane coupling agent layer on the surface.