JP5865802B2 - Pre-evaluation method for anti-rust effect and method for constructing short-term distribution model of anti-rust component concentration of neutralized concrete - Google Patents

Description

  The present invention relates to a reinforced concrete (Reinforced-Concrete) (hereinafter also referred to as “RC”) structure or prestressed concrete (Prestressed-Concrete) (hereinafter also referred to as “PC”) in a neutralized concrete rebar. About the concrete structure life extension processing method which gives a rust prevention effect, the method (henceforth "rust prevention effect prior evaluation method") for evaluating the rust prevention effect by the method before construction of the method concerned, and It relates to a method for building a short-term distribution model of rust-preventive component concentration of neutralized concrete.

<About salt damage and neutralization of concrete structures>
Salt damage and neutralization related to concrete structures are known as the main causes of deterioration of concrete structures by causing corrosion of reinforcing bars in concrete.

<About salt damage>
Salt damage is affected by concrete structures constructed using undesalted sea sand, concrete structures near the coast where salinity comes in and adheres to the surface, and anti-freezing agents. As for concrete structures, the concentration of chloride ions in the vicinity of reinforcing bars in concrete increases, and the passive film formed on the reinforcing bar surface is destroyed to protect the reinforcing bars from corrosion. It is a deterioration phenomenon that progresses.

  In the following description, “concentration” means “mass / volume concentration” unless otherwise specified.

<About neutralization>
Neutralization is a deterioration phenomenon in which carbon dioxide gas (CO2) in the atmosphere enters into the concrete of the concrete structure, calcium hydroxide changes to calcium carbonate, and the alkalinity of the concrete decreases. For example, it is known that the hydroxide ion index of neutralized concrete decreases from about pH 12-13 to about pH 8.2-10. When the neutralized region reaches the vicinity of the reinforcing bar of the concrete structure, the passive film formed on the surface of the reinforcing bar is destroyed, and therefore, the deterioration phenomenon that the corrosion of the reinforcing bar starts and progresses like the salt damage occurs.

  A passive film is a very thin protective film formed on the surface of a reinforcing bar when the hydroxide ion index (hereinafter also referred to simply as “pH”) in the environment where the reinforcing bar is disposed (for example, inside concrete) is high. Reinforcing bar corrosion reaction is suppressed by the formation of this “passive film”.

<Relationship between neutralization progress and neutralization depth>
FIG. 1 is an explanatory diagram relating to the neutralization depth, FIG. 1 (a) is a model diagram showing a neutralization region inside the concrete structure, and FIG. 1 (b) is an actual concrete. It is the drawing substitute photograph which showed the neutralization area | region inside a structure.

  As shown in FIGS. 1 (a) and 1 (b), the progress of neutralization is determined by the magnitude of the neutralization depth. Here, the neutralization depth is the depth (thickness) of the neutralization region formed on the surface portion of the concrete.

  The neutralization depth is measured, for example, by taking a concrete core (a columnar concrete sample; hereinafter simply referred to as “core”) from a concrete structure, and phenolphthalein 1% on the outer peripheral surface of the core. When the ethanol solution is sprayed, as shown in FIG. 1B, the neutralized region of the core does not change color (the whitish region on the left side of FIG. 1B), and the non-neutralized region of the core changes color due to alkalinity. (The dark area on the right side of FIG. 1B).

  Therefore, the depth (thickness) from the core surface of the non-discolored region (the whitish region on the left side of FIG. 1B) in this core, that is, the neutralized region, is measured, and the average value of the measured values is neutral. Depth of formation. In addition, in Fig.1 (a) and FIG.1 (b), in the measurement of neutralization depth, in addition to the neutralization depth which is an average value of an actual measurement value, the maximum in the measurement value is shown. The value (maximum neutralization depth (hereinafter referred to as “neutralization depth maximum value”)) is also obtained.

<Relationship between each component of concrete structure and neutralization depth>
FIG. 2 (a) shows the neutralization of each part of the concrete structure, for example, PC girder, PC hollow floor slab, steel rigid floor slab, steel bridge RC floor slab, RC hollow floor slab, railing, abutment and pier. It is the table | surface which showed the actual value of the speed coefficient. FIG.2 (b) is the graph which showed the relationship between the average value of the measured value of the neutralization rate coefficient of each site | part shown to Fig.2 (a), and a water cement ratio.

  Figure 2 (b) shows the Japan Society of Civil Engineers' Concrete Committee / Concrete Standard Specification Revision Subcommittee (2008) “Concrete Standard Specification / Maintenance / Established in 2007”. The estimated value (predicted value) of the neutralization rate coefficient (hereinafter referred to as “specification estimated value”) shown in FIG.

  The letter “M” in FIG. 2A indicates the position of the average value of the actual measurement value of the neutralization speed coefficient, the letter “σ” indicates the position of the standard deviation of the actual value of the neutralization speed coefficient, The inverted triangle marks indicate the estimated values of the specifications.

  That is, the left end of each bar graph in FIG. 2A is “average value−standard deviation” (M−σ), the center line is “average value” (M), and the right end is “average value + standard deviation” ( M−σ) respectively.

<Relationship between neutralization depth and neutralization rate coefficient>
The concrete structures shown in FIGS. 2 (a) and 2 (b) are highways in the Hokuriku region, and 19 to 36 years have passed since construction. Here, the neutralization depth is represented using the relationship between the elapsed years after the construction of the concrete structure and the neutralization rate coefficient, as shown in Formula (1-1).
C = A × √ (t) (1-1)

  However, in Formula (1-1), C (mm) is the neutralization depth, A (mm / √year) is the neutralization rate coefficient, t (year) is the number of years since construction, √ () ”means the“ square root ”of the numerical value, variable or expression in“ () ”that follows.

  In the specification, the neutralization rate coefficient is defined as a linear function of the water cement ratio (W / C).

<Neutralization speed of RC floor slab>
As shown in Fig. 2 (a) and Fig. 2 (b), the measured value of the neutralization rate coefficient A for the balustrades, abutments and piers that are easily wetted by rainwater, The value is relatively close to the estimated value. On the other hand, for superstructures such as girders and floor slabs that are easy to dry, the actual measurement value of the neutralization rate coefficient A greatly exceeds the estimated value of the specifications.

  Moreover, the steel bridge RC floor slab, RC hollow floor slab, and handrail (see the plot with the mark “(Head)” in FIG. 2B) are based on the water cement ratio (W / C). Although the composition shown is constructed from concrete with almost the same composition, as shown in Fig. 2 (a), the average value of the neutralization rate coefficient for steel bridge RC slabs and RC hollow slabs is 3 or more. On the other hand, the average value of the neutralization rate coefficient regarding the railings was less than 1, and the former was about 3 times or more of the latter.

  In view of these points, it can be said that the progress of neutralization of RC floor slabs such as steel bridge RC slabs and RC hollow floor slabs in a dry environment is extremely high.

<Relationship between neutralization and RC corrosion in RC slab>
By the way, on page 94 of the specification, regarding the relationship between the neutralization depth and the reinforcement corrosion, the start time of the reinforcement corrosion is indicated by “neutralization residual” which is the difference between the reinforcement cover thickness and the neutralization depth. It is described that. In addition, in general, the start of corrosion of reinforcing steel bars is when the neutralization residue is 10 mm, and when the concrete contains chloride ions, the neutralization residue is less than about 15 mm. It is also described that the proportion of concrete structures where steel corrosion becomes significant increases.

  For this reason, rebar corrosion due to neutralization in RC floor slabs tends to start earlier when chloride ions penetrate into concrete than when it does not. It can be said.

  If it does so, about the RC floor slab in a concrete structure, there exists a tendency for neutralization to advance easily, and when salt damage accompanies neutralization, there is a problem that progress of rebar corrosion is further accelerated. It is considered a thing. In particular, for steel bridge RC floor slabs with relatively thin concrete parts, the progress of neutralization and the progress of rebar corrosion accompanying the combination of neutralization and salt damage are considered to be more prominent. It is done.

<Deterioration process of RC slabs>
Fig. 3 (a) shows the deterioration of the steel bridge RC floor slab caused by fatigue shown in the above-mentioned specification (refer to page 188 of the same book, see Figure 14.3.1 "Progress of cracks on the bottom of the slab"). It is the figure which showed the progress process. FIG. 3B is a drawing-substituting photograph showing the state of precipitation of free lime (the whitish portion in the figure) from the steel bridge RC floor slab.

  As shown in FIG. 3 (a), when a general steel bridge RC floor slab is deteriorated due to fatigue, water infiltrates into the concrete having fine cracks due to drying shrinkage of the concrete, and the steel bridge RC floor slab is repeatedly rotated. By applying a load, a turtle-shell-like crack (states II to III in FIG. 3A develops), and the crack penetrates the floor slab in the thickness direction (depth direction).

  And when road surface water infiltrates into a penetration crack, as shown in FIG.3 (b), precipitation of free lime (refer to the crack image figure corresponding to the states II-III of Fig.3 (a)) will appear on a floor slab lower surface. It is. In particular, in steel bridge RC floor slabs sprayed with anti-freezing agents, salt damage occurs due to the permeation of salt-containing road surface water, which acts in combination with deterioration due to fatigue. It will be.

  FIG. 4A is a cross-sectional view of an RC floor slab that describes a deterioration process of the RC floor slab caused by salt damage. As shown in FIG. 4 (a), first, the road surface water containing salt penetrates the pavement and penetrates to the upper surface of the floor slab ((1) in the figure), and the reinforcing bars near the upper surface of the floor slab begin to corrode (see FIG. 4). Medium (2)), fogging of the cover and potholes of pavement occur.

  Then, when the crack penetrates in the thickness direction of the RC floor slab ((3) in the figure), the road surface water flows down to the floor slab lower surface through this crack and spreads in the plane direction along the floor slab lower surface ( In the figure (4)), free lime (see FIG. 3B) precipitates from the concrete on the bottom of the floor slab.

  And when this RC floor slab is repeatedly subjected to drying and wetting due to the influence of weather changes etc. ((5) in the figure), the water containing salt is concentrated, and this concentrated salt water penetrates into the concrete from the bottom of the floor slab. ((6) in the figure).

  In particular, at this stage, when the concrete of the steel bridge RC floor slab is being neutralized, corrosion of the lower rebar of the floor slab is accelerated, and as a result, concrete floats and peels off the bottom of the floor slab. It is thought to occur.

  FIG. 4 (b) is a drawing-substituting photograph showing the state of salt infiltration on the cut surface of the actually deteriorated RC floor slab. The RC floor slab shown in FIG. 4 (b) visualizes the state of penetration of chloride ions inside the concrete by spraying a silver nitrate solution on the cut surface.

  As shown in FIG. 4B, on the cut surface of the RC floor slab, the black discolored portion is a region where chloride ions are permeating. In addition, horizontal cracks in the vicinity of the upper rebar of the cut surface of the RC floor slab and its vicinity, through cracks and the vicinity thereof, and the fogging area on the bottom of the floor slab are discolored in black. It can be seen that this is an infiltration region.

<About the combined action of salt damage and neutralization on the underside of RC slabs>
FIG. 5A is a graph showing the chloride ion concentration distribution in the depth direction obtained from the core taken from the bottom surface of the RC slab that has been in service for 30 years.

  As shown to Fig.5 (a), the chloride ion density | concentration in the concrete of the floor slab lower surface of a sound RC floor slab is in the very low condition (about 0 kg / m3). In contrast, when the deterioration of the upper surface of the floor slab proceeds, a large amount of chloride ions have permeated into the concrete on the lower surface of the floor slab of the RC floor slab.

  In particular, the chloride ion concentration on the back of the neutralized area on the bottom of the floor slab (area deeper than the depth indicated by the dotted line in the figure) is high, and the lower rebar (see FIG. 4 (a)) is salt damage and neutralized. It is considered to be in a corrosive environment in which and are acting in a complex manner.

  Fig. 5 (b) is a graph showing the results of investigating the relationship between the chloride ion concentration distribution penetrating into the concrete and the maximum neutralization depth according to the degree of deterioration of the steel bridge RC slab. It is.

  In this investigation, cores were sampled from the bottom surface of the three types of steel bridge RC floor slabs in each of the latent period, progress stage, and acceleration period, and the cores of each degree of degradation were separated by a predetermined width Δx in the depth direction. (= 5 mm) is sliced into a plurality of elements, each of the elements sliced into the plurality is pulverized, and the chloride ion concentration is measured from the pulverized product by potentiometric titration (JIS-A1154).

  In FIG.5 (b), the measured value of the chloride ion density | concentration by the above-mentioned investigation is plotted for every depth of the floor slab, and the chloride ion accompanying the difference in the deterioration degree of the steel bridge RC slab Concentration distributions are compared. FIG. 5B also shows the maximum neutralization depth values measured in accordance with JIS-A1152 for the cores having three types of deterioration levels.

  According to the above specification, the chloride ion concentration at which the reinforcing bar begins to corrode in the concrete (corrosion rust limit chloride ion concentration) is generally 1.2 kg / m3 (concrete). Measured under conditions where neutralization has not progressed, and due to the progress of neutralization and the decrease in the hydroxide ion index (pH) near the reinforcing bars, the corrosion rust limit chloride ion concentration is It is assumed to be smaller.

  According to FIG. 5 (b), it is considered that the RC floor slab in the advanced stage has a chloride ion concentration of about 1.5 kg / m3 in the vicinity of the reinforcing bar on the bottom surface of the floor slab, and corrosion of the reinforcing bar has started. . Further, in the RC floor slab in the deterioration period, cracks due to corrosion occurred near the reinforcing bars on the bottom of the floor slab, and the chloride ion concentration near the reinforcing bars exceeded 3 kg / m3. Moreover, it was confirmed that the depth at which the chloride ion concentration becomes maximum is generally at the position of the reinforcing bar cover thickness (about 35 mm) on the bottom side of the floor slab (hereinafter referred to as “reinforcing bar position”).

  From the above, concrete structures such as RC slabs (especially steel bridge RC slabs) are concrete on the underside of the slab that is in a neutralized state under the condition of deterioration from the development stage to the acceleration stage. There is a significant increase in the chloride ion concentration at the position of the reinforcing bar cover thickness (hereinafter also referred to as “rebar position”), and it is necessary to suppress the corrosion of the reinforcing bar by the chloride ion and to prolong its life it is conceivable that.

<Measures to prevent rebar corrosion on the underside of RC slabs>
Therefore, the applicant of the present application is concerned with the RC floor slabs whose deterioration degree has reached the latter half of the development period or the acceleration period, by preventing rebar corrosion in the concrete in a neutralized state like the bottom surface of the floor slab. We have come to propose a new method for extending the life of concrete structures that suppresses the deterioration of the plate and extends its life.

  This new method for extending the life of concrete structures has an advantageous effect in preventing corrosion of reinforcing steel bars due to neutralization, such as the bottom surface of RC slabs whose deterioration is in the late development stage or acceleration stage. This is a technique that has not yet been publicly known.

  FIG. 5 (c) shows concrete (including reinforced concrete) in a neutralized state (a state having a neutralized region) that has been repaired by a concrete structure life extension processing method (hereinafter referred to as "neutralization"). It is also referred to as “concrete”).

  As shown in FIG.5 (c), this concrete structure life extension processing method is neutralization and salt damage by the influence of the antifreezing agent containing sodium chloride, or using sea sand for concrete, for example. Uses mortar mixed with a large amount of rust-preventive components on the RC floor slab where deterioration is progressing due to the combination of rust, especially on the surface of neutralized concrete such as the bottom of the floor slab. It is a kind of surface coating method in which the surface of the rust preventive repair material is applied (applied) with a thickness of several millimeters to form a coating layer of the rust preventive repair material.

  Here, the rust preventive repair material is, for example, a mixture of polymer and short fibers in mortar, and is manufactured by mixing the rust preventive component so that the ion concentration (amount) is about 60 to 70 kg / m 3. It has been done. Further, as the rust preventive component, for example, an ionic component having a rust preventive effect such as nitrite nitrite ion, sodium nitrite or calcium nitrite, amine ethanolamine, or aminocarboxylate (MCI- 2081, HK-110008-A). ) Is used.

  By the way, prior to the construction of such a concrete structure life extension processing method, it is considered preferable to conduct a prior evaluation for confirming the rust prevention effect of the rust prevention repair material which is planned to be constructed in advance. .

  Therefore, the applicant of the present application has independently neutralized the rust preventive repair material in order to confirm the effect of the rust preventive component on the neutralized concrete in this concrete structure life extension processing method. For the case where a surface layer is applied to the concrete surface to form a coating layer, and for the case where the surface layer is applied to the concrete surface in an unneutralized state, the coating layer is formed for a predetermined period from the surface application. A test was conducted to compare the concentration distribution of the anticorrosive component after the passage.

  In addition, in this short-term penetration confirmation test of rust-preventive components for this rust-preventive repair material, the concentration distribution of rust-preventive components after the penetration test period of 4 months has elapsed from the point of application of the rust-preventive repair material as a repair layer. We decided to compare.

  FIG. 6A is a schematic cross-sectional view of a concrete structure, specifically, an RC floor slab, to be treated by a concrete structure life-extending treatment method using a rust-proof repair material. FIG. 6 (b) shows an example of the sampling position of the core used in the short-term penetration confirmation test. FIG. 6 (b) shows the effect of the rust preventive repair material created using the core sampled from the concrete structure of FIG. 6 (a). It is a perspective view of the test body for confirmation.

  As shown to Fig.6 (a), a core is extract | collected from a concrete structure (W / C = 55%), an outer diameter is 55 mm, and a length is 100 mm. The concrete structure from which this core was sampled is about 35 years old after construction. Further, as a result of measuring the neutralization depth of the peripheral surface of the core, the neutralization depth (average value) was 18 mm, and the maximum neutralization depth was 21 mm.

  As shown in FIG. 6 (b), the test body is composed of the above-described core surface side (one axial end side of the core and the concrete wall surface side) and the back side of the core (the other axial end of the core). Apply polymer cement mortar containing short fibers mixed with rust-preventive ingredients on both sides of the concrete wall (on the deep side of the concrete wall) as a rust-proof repair material, and apply epoxy resin to the core circumference. It is formed by that.

  The surface side of the core is a neutralized concrete surface, and the back side of the core is a non-neutralized concrete surface (hereinafter also referred to as “non-neutralized concrete surface”).

  The specimen prepared in this way is naturally exposed to the penetration test period (4 months) in a state where it is not exposed to rainwater outdoors for a short-term penetration confirmation test of the anticorrosive component. Slice cut into multiple elements in the depth direction (axial direction of the core) with width Δx (= 5mm), crush each of the multiple slice cut elements, and add warm water to the pulverized product to elute rust preventive ingredients Then, the concentration of the anticorrosive component was measured by an ion chromatogram, and the concentration in the depth direction of the anticorrosive component permeating into the concrete was measured.

  In addition, in the short-term penetration confirmation test of the rust preventive component, a test specimen using a polymer cement mortar containing short fibers mixed with nitrite ions having a total concentration of 61 kg / m3 as a rust preventive component as a rust preventive repair material. And made an experiment.

  FIG. 7 is a graph showing the results of a short-term penetration confirmation test of a rust-preventing component using the above-described test specimen, and the surface is coated with a rust-proof repair material on the neutralized concrete surface and the non-neutralized concrete surface. In this case, the concentration distribution of the rust preventive component that has penetrated into the concrete (core) during the penetration test period (4 months) is shown.

  Here, in FIG. 7, the neutralized concrete surface and the non-neutralized concrete surface of the core are each 0 mm, and the surface of the repair layer formed of the rust-proof repair material having a thickness of 5 mm is expressed as a depth of −5 mm. Yes. Moreover, the position of each data plot of FIG. 7 is each depth element xi (i = 0, 1) in the range from the surface (depth-5 mm) of the repair layer of a rust preventive repair material to a deep part (depth 45 mm). ,..., N−1, n (n is a natural number) and width Δx = 5 mm), specifically, the medians are −2.5 mm, 2.5 mm, 7.5 mm,.・ ・ 42.5mm.

  Here, the depth element xi is a section that is equally spaced at a predetermined width Δx in the depth direction of the concrete, and each depth element xi is a shallow boundary value (boundary depth) (xi). [Min]) to the boundary value (xi [max]) on the deep side.

  The range of the depth element xi is, for example, (b) a range (xi [min] ≦ xi <xi [max]) that is not less than the boundary value on the shallow side and less than the boundary value on the deep side. ) Although the boundary value exceeding the boundary value on the shallow side and below the boundary value on the deep side may be set as the range (xi [min] <xi ≦ xi [max]), the former (A) is adopted in this embodiment. .

  In addition, among the graphs (distribution curves) showing the concentration distribution in FIG. 7, the “neutralization present” graph is obtained by applying a rust preventive repair material to the neutralized concrete surface, “no neutralization” These graphs show rust preventive repair materials applied to the surface of non-neutralized concrete.

  As shown in FIG. 7, for the neutralized concrete surface, many rust preventive components penetrate into the core, up to the non-neutralized region near the boundary between the neutralized region and the non-neutralized region, It was confirmed that the rust preventive component was moving.

  Specifically, for the rust preventive repair material applied to the surface of the neutralized concrete shown in FIG. 7, the initial mixed total concentration Σα of the rust preventive component is 61 kg / m 3, while The total concentration of the rust preventive component in the non-neutralized region deeper than 20 mm is 9.9 kg / m3, and the amount of the rust preventive component corresponding to about 16% of the total initial concentration Σα is deeper than the depth of 20 mm. It has penetrated to the non-neutralized region.

  In this way, in the case of neutralized concrete surface, the rust preventive repair material penetrates to the non-neutralized region where the amount of rust preventive component corresponding to about 15% of the initial total concentration Σα is deeper than 20 mm deep. In particular, it can be seen that the concentration of the rust preventive component in the non-neutralized region near the boundary between the neutralized region and the non-neutralized region reaches about 6 kg / m 3.

  On the other hand, on the non-neutralized concrete surface, it is thought that the penetration of the rust preventive component is due to the general concentration difference diffusion, so the total concentration of the rust preventive component penetrating into the concrete is the neutralized concrete surface. It was confirmed that it was less than

  Specifically, with respect to the anticorrosive repair material applied to the surface of the non-neutralized concrete surface, the initial concentration Σα of the anticorrosive component is 61 kg / m3, whereas the depth of the anticorrosive repair material is deeper than 20 mm. The total concentration of rust-preventive components in the carbonization region is 1.7 kg / m3, and the amount of rust-preventive components equivalent to about 2.8% of the initial total concentration Σα is unneutralized deeper than 20 mm deep. It penetrates to the area.

  As described above, in the case of the non-neutralized concrete surface, the rust preventive repair material penetrates into the non-neutralized region where the amount of the rust preventive component corresponding to about 2% of the initial total concentration Σα is deeper than 20 mm. It is a little compared to the neutralized concrete surface.

  From the above, according to the short-term penetration confirmation test of the rust preventive component shown in FIGS. 6 and 7, for the neutralized concrete, the rust preventive repair material in which the rust preventive component is mixed on the surface of the neutralized concrete. Short-term penetration characteristics that when a surface coating is applied, a phenomenon occurs in which many rust preventive components penetrate into the non-neutralized region near the boundary between the neutralized region and the non-neutralized region during a penetration test period of about 4 months. It was confirmed that there is.

  Therefore, if the short-term penetration characteristics of this neutralized concrete is used, the rust-preventive component is infiltrated into the concrete in a short time from the rust-proof repair material applied to the surface of the neutralized concrete, and the penetration effect (results) ) Can be confirmed immediately after the short period of time, and by considering the confirmation results, it is easy to select a method for implementing more effective countermeasures, such as by appropriately changing the amount of rust-preventive ingredients mixed in. It is considered possible.

  In addition, it is estimated that the short-term penetration characteristic of this neutralized concrete originates in the water containing a rust preventive component moving inside by a capillary phenomenon. In addition, according to Fig.5 (a) and FIG.5 (b), also about the chloride ion density | concentration of the neutralization concrete in a floor slab lower surface in the non-neutralization area | region side (deep part side) rather than neutralization depth. A phenomenon (characteristic) similar to the concentration distribution of the anticorrosive component appears.

Japanese Patent No. 4496188

Hirohito Asakura and Fumio Taguchi (2004) “Analysis of salt infiltration of concrete members using numerical analysis by finite difference method” “2004 Annual Report of Hokkaido Society of Civil Engineering Hokkaido Chapter” 61

  However, the concentration distribution of rust-preventing components in non-neutralized concrete generally shows a diffusion tendency (permeation characteristic) due to the difference in concentration, whereas the concentration distribution of rust-preventing components in neutralized concrete is 4 Since a large amount of the rust preventive component penetrates into the concrete in a short period of about a month, it tends to have a tendency (penetration characteristics) different from the diffusion tendency due to a general concentration difference.

  Therefore, for neutralized concrete, Fick's second law (diffusion equation) is used to predict the concentration distribution of rust-preventive components from the surface application time of the repair layer (rust-proof repair material) to any future time point. When numerical analysis (numerical calculation) is performed using a one-dimensional difference equation (hereinafter referred to as "Fick's diffusion difference equation"), which is an approximate expression, the concentration of rust-preventing components at the time of surface application of the repair layer (rust-preventing repair material) If the distribution is assumed to be the initial condition, the concentration distribution of the rust preventive component cannot be accurately predicted, and it is not possible to accurately perform the preliminary evaluation as to whether or not the rust preventive atmosphere due to the rust preventive component is formed at the reinforcing bar position. There was a problem.

  As for Fick's diffusion difference equation, the above-mentioned Patent Document 1 and Non-Patent Document 1 (Asakura Hirohito, Taguchi Fumio (2004) “Salt penetration analysis of concrete members using numerical analysis by the difference method” “FY 2004 Civil Engineering” Please refer to Academic Society Hokkaido Chapter Papers No.61).

  The present invention was made to solve the above-described problems, and can predict the concentration distribution of rust-preventing components using Fick's diffusion difference equation for neutralized concrete, and It aims at providing the rust prevention effect prior evaluation method which can perform prior evaluation about whether the rust prevention atmosphere by the said rust prevention component is formed in the reinforcing bar position of neutralized concrete.

In order to achieve this object, the rust preventive effect prior evaluation method according to claim 1 is characterized in that a rust preventive material mixed with a rust preventive component is applied to a neutralized concrete surface coated with a predetermined thickness as a repair layer. A rust preventive component concentration predicting step for predicting, in the rust preventive effect pre-evaluation method for pre-evaluating whether or not a rust preventive atmosphere can be formed at a reinforcing bar position of a concrete structure by this rust preventive component concentration predicting step; The component concentration prediction process performs numerical calculation of Fick's diffusion difference equation using the short-term distribution model of rust-preventive component at the time when a predetermined short-term penetration period has elapsed since the surface coating of the repair layer as an initial condition. The rust preventive component concentration distribution in the neutralized concrete at the time is predicted, and the rust preventive component concentration short-term distribution model is a predetermined short-term penetration from the time of surface application of the repair layer. At the time the between has passed, the depth of the amount of the rust preventive component equal to the initial contamination total concentration Σα comprises neutralization depth was measured using a core taken from be repaired neutralization concrete from the surface of the repair layer The rust preventive component concentration of each depth element xi is assumed to be an ideal uniform distribution concentration αm when it is assumed that the distribution is uniform in each depth element xi within the ideal permeation range D3 ranging up to the element xi, and The ideal uniform distribution concentration αm was measured in a short-term penetration confirmation experiment of a predetermined short-term penetration rate γ or a neutralization depth measured using the core and a rust-preventive component of the anti-rust repair material using the core. No rust inhibitor component concentration obtained by multiplying the short-term penetration rate γ determined based on the value calculated using the neutralization depth, and the uniform distribution concentration βm, the rust inhibitor component concentration is within the ideal penetration range D3. At each depth element xi, the deemed uniform distribution density In the depth element xi that is uniformly distributed at a degree βm and deeper than the ideal permeation range D3, the rust preventive component is constructed to be uniformly non-permeated.

  The “neutralization depth” described in the present invention may be the so-called “neutralization depth”, which is an average value of measured values of the neutralization depth. “Maximization depth” may be used.

  The rust prevention effect prior evaluation method according to claim 2 is the depth evaluation element according to claim 1, wherein an amount of the rust prevention component equal to the initial mixed total concentration Σα is within the ideal penetration range D3. xi is assumed to be uniformly distributed in the short-term penetration period, and the initial mixed total concentration Σα is divided by the number k of depth elements xi within the ideal penetration range D3 to obtain the ideal uniform distribution concentration αm. Is calculated.

The rust prevention effect prior evaluation method according to claim 3 is the rust prevention effect prior evaluation method according to claim 1 or 2, wherein the short-term penetration rate γ is a uniform penetration distribution of a rust prevention component with respect to the ideal uniform distribution concentration αm. The ideal uniform distribution concentration αm is calculated as a ratio of the concentration ρm, and the amount of the rust preventive component equal to the initial mixed total concentration Σα is in each depth element xi within the ideal penetration range D3. suppose uniformly distributed by the short penetration period Te is calculated by dividing the initial contamination total concentration Σα the number k of depth elements xi in its ideal penetration range D3, already osmotic uniform distribution density ρm Is the depth including the neutralization depth measured in the short-term penetration confirmation experiment of the anticorrosive component of the anticorrosive repair material using the core from the shallowest set depth. Each depth element x in the existing penetration range D2 ranging up to the depth element xi Assuming a uniform distribution at i, it is calculated by dividing the examination total concentration Σρ by the number m of the depth element xi in the existing penetration range D2, and the examination total concentration Σρ of the antirust component is the repair layer Measure the antirust component concentration distribution in the depth direction from the surface of the repair layer at the time when the predetermined penetration test period has elapsed from the time of surface coating of the rust preventive component, and from this measurement result, It is calculated by summing up the rust preventive component concentration of each depth element xi within the examination range D1 in which the depth is not less than the set depth.

The rust preventive component concentration short-term distribution model construction method for neutralized concrete according to claim 4 is used in the rust preventive effect prior evaluation method according to claim 1 or 2, and the rust preventive component concentration short-term distribution for neutralized concrete. This is a method of building a model.When a specified short-term penetration period has elapsed since the surface of the repair layer was applied, the amount of rust-preventive component equal to the initial total concentration Σα is neutralized from the surface of the repair layer . Depths when assuming uniform distribution in each depth element xi within the ideal infiltration range D3 ranging from the depth element xi including the neutralization depth measured using the core taken from the concrete The rust preventive component concentration of the element xi is calculated as an ideal uniform distribution concentration αm, and when a predetermined short-term penetration period has elapsed since the surface coating of the repair layer, the predetermined uniform short-term immersion is performed at the ideal uniform distribution concentration αm. A value calculated using the rate γ or neutralization depth measured by short-term penetration confirmation experiment anticorrosive ingredients rust repair material by using a neutralization depth and the core was measured using the core Random component concentration obtained by multiplying the short-term penetration rate γ determined on the basis of the calculated value as a uniform distribution concentration βm, and when the prescribed short-term penetration period has elapsed since the surface coating of the repair layer, However, at each depth element xi of the ideal penetration range D3, the rust preventive component is uniformly distributed at the depth element xi that is uniformly distributed at the assumed uniform distribution concentration βm and deeper than the ideal penetration range D3. In this way, a short-term distribution model of rust preventive component concentration is constructed assuming that it has not penetrated.

The method for constructing a short-term distribution model of rust-preventive component concentration for neutralized concrete according to claim 5 is the method for constructing a short-term distribution model of rust-preventive component concentration for neutralized concrete according to claim 4, wherein the short-term permeability γ is the ideal one. It is calculated as a ratio of the pre-penetrated uniform distribution concentration ρm of the rust preventive component to the uniform distribution concentration αm, and the ideal uniform distribution concentration αm has an amount of the rust preventive component equal to the initial mixed total concentration Σα. Assuming that each depth element xi in the ideal penetration range D3 is uniformly distributed in the short-term penetration period, the initial total concentration Σα is the number k of depth elements xi in the ideal penetration range D3. The osmotic uniform distribution concentration ρm is calculated by dividing the rust-preventing component in an amount equal to the total concentration to be studied Σρ from the shallowest set depth to the depth element xi including the neutralization depth. Each within the permeation range D2 Assuming a uniform distribution at the depth element xi, it is calculated by dividing the examination total concentration Σρ by the number m of the depth elements xi within the already infiltrated range D2, and the examination total concentration Σρ of the anticorrosive component is The rust inhibitor component concentration distribution in the depth direction from the surface of the repair layer at the time when the predetermined penetration test period has elapsed since the surface coating of the repair layer was measured by a short-term penetration confirmation test of the rust preventive component. The calculation is performed by summing up the rust preventive component concentrations of the respective depth elements xi within the examination range D1 in which the depth is less than or equal to the shallowest set depth.

  According to the rust prevention effect prior evaluation method of the present invention or the rust prevention component concentration short-term distribution model construction method of neutralized concrete, numerical calculation of Fick's diffusion difference equation is performed with the rust prevention component concentration short-term distribution model construction as an initial condition. By doing so, it is possible to predict the concentration distribution of rust-preventive components at any future time according to the penetration characteristics of the specific rust-preventive components found in neutralized concrete, and to evaluate the effects of rust-preventive components in advance The effect is that it can be performed more accurately and easily.

It is explanatory drawing regarding the neutralization depth, (a) is a model figure which showed the neutralization area | region in the inside of a concrete structure, (b) is neutralization inside an actual concrete structure It is the drawing substitute photograph which showed the area | region. (A) is a table | surface which showed the measured value of the neutralization rate coefficient about each site | part of a concrete structure, (b) is the measured value of the neutralization rate coefficient of each site | part shown to (a). It is the graph which showed the relationship between an average value and a water cement ratio. (A) is the figure which showed the progress process of deterioration by fatigue of a steel bridge RC floor slab, (b) is a drawing substitute photograph which showed the free lime precipitation situation from a steel bridge RC floor slab. (A) is a cross-sectional view of an RC floor slab explaining the deterioration process of the RC floor slab due to salt damage, and (b) is a drawing substitute photograph showing the state of salt infiltration on the cut surface of the actually deteriorated RC floor slab. It is. It is the graph which showed the chloride ion concentration distribution in the depth direction obtained from the core extract | collected from the floor slab bottom of RC floor slab which has passed 30 years after service. It is the graph which showed the result of investigating the relationship between chloride ion concentration distribution which penetrate | infiltrated into concrete, and the neutralization depth maximum value according to the progress of deterioration of steel bridge RC floor slab. It is sectional drawing of the concrete which became the neutralization state by which the repair by the concrete structure life extension processing method was performed. (A) is an example of a sampling position of a core used for a short-term penetration confirmation test of a rust-preventing component, and (b) is an anti-corrosion prepared using a core collected from the concrete structure of (a). It is a perspective view of the test body for the effect confirmation of a rust repair material. It is the graph which showed the result of the short term osmosis | permeation confirmation test of the antirust component using the test body of FIG.6 (b). It is a flowchart of the rust prevention effect prior evaluation method regarding the concrete structure life extension processing method which is one Example of this invention. (A) is explanatory drawing of calculation process (S41) of examination total density | concentration (SIGMA) (rho), (b) is explanatory drawing of calculation process (S42) of already osmosis | permeation uniform distribution density | concentration (rho) m. (A) is explanatory drawing of calculation process (S43) of ideal uniform distribution density | concentration (alpha) m based on initial stage mixing total density | concentration (SIGMA) (alpha), (b) is explanatory drawing of calculation process (S44) of short-term permeability γ. Therefore, this is a mathematical formula for obtaining the short-term permeability γ. It is explanatory drawing of the determination process (S45) of an antirust component density | concentration short-term distribution model, Comprising: (a) is a graph which showed the antirust component density | concentration short-term distribution model in particular, (b) is (a). It is the graph which made the difference model the shown antirust component density | concentration short-term distribution model. (A) is the figure which showed the element division | segmentation used for the numerical calculation of Fick's diffusion difference equation, (b) shows Fick's diffusion difference equation constructed | assembled based on the element division of (a) (C) shows an example of setting initial conditions of Fick's diffusion difference equation shown in (b). It is the graph which showed an example of the numerical analysis result which predicted the antirust component concentration distribution in neutralized concrete by the prediction process (S5) of the antirust effect prior evaluation method shown in FIG. 13 is a chart showing the relationship between the initial concentration Σα of the rust-preventive component that can form a rust-preventive atmosphere at the position of the reinforcing bar in the neutralized concrete and the chloride ion concentration using the conditions exemplified in FIG. is there.

  A preferred embodiment of the present invention will be described below with reference to FIGS. FIG. 8 is a flowchart of a rust prevention effect prior evaluation method relating to a concrete structure life extension treatment method (hereinafter also simply referred to as “life extension treatment”) according to an embodiment of the present invention.

  As shown in FIG. 8, according to the rust prevention effect prior evaluation method, first, a core is sampled from neutralized concrete such as RC floor slab to be processed by the life extension process (S1), and this core is used. The neutralization depth (average value) and the maximum neutralization depth are measured (S2). For the collection of the core, refer to the description of FIG. 6, and for the measurement of the neutralization depth (average value) and the maximum neutralization depth, refer to the description of FIG.

  Separately from the measurement of neutralization depth (average value) and maximum neutralization depth (S2), the short-term penetration confirmation test of rust-preventive components for neutralized concrete using the core collected in step S1 (S3). In addition, please refer to description of above-mentioned FIG.6 and FIG.7 for the specific method of the short-term penetration confirmation test (S3) of the rust prevention component of neutralized concrete.

  After the short-term penetration confirmation test in step S3, based on the measurement results of this test, the neutralized concrete at the time when a predetermined short-term penetration period has elapsed since the surface of the neutralized concrete was coated with a rust preventive repair material. The rust preventive component concentration distribution model (hereinafter referred to as “rust preventive component concentration short-term distribution model”) is constructed (S4) (refer to the description of FIGS. 9 to 11 described later).

  Here, in the construction step (S4) of the antirust component concentration short-term distribution model, the calculation step (S41) of the examination total concentration Σρ, the calculation step (S42) of the existing permeation uniform distribution concentration ρm, and the initial mixed total concentration Σα. The calculation step (S43) of the ideal uniform distribution concentration αm based on the above, the calculation step (S44) of the short-term penetration rate γ, and the determination step (S45) of the anti-rust component concentration short-term distribution model are performed in order.

  Then, Fick's diffusion difference equation is numerically calculated as an initial condition (see FIG. 12 (c)) using a rust-preventive component concentration short-term distribution model constructed through the S4 (S41 to S45) process, and neutrality at any future time point. The antirust component concentration distribution in the reinforced concrete is predicted (S5) (refer to the description of FIG. 12 described later).

  Then, based on the prediction result of the concentration distribution of the rust-preventing component in the neutralized concrete, the concentration of the rust-preventing component at any future time point is obtained (S6), and the chloride ion at the position of the reinforcing bar at the same future time point is obtained. The concentration is predicted and obtained (S7), and it is determined whether or not the concentration of the rust preventive component relative to the chloride ion concentration at the position of the reinforcing bar at this future time is equal to or higher than a value capable of forming a rust preventive atmosphere (S8).

  The rust-proof atmosphere is a state in which the molar ratio of the rust-preventing component to chloride ions is 0.8 or more. The ratio divided by is converted into moles.

  However, the prediction of the chloride ion concentration at the position of the reinforcing bar at any future time (S7) is described in, for example, the above-mentioned Patent Document 1 and Non-Patent Document 1, “Concrete member analysis using numerical analysis by the difference method”. Conventional methods such as “salt infiltration analysis” are used.

  In this way, the rust prevention effect preliminary evaluation method is based on the measurement result of the short-term penetration confirmation test of the rust prevention component used for the life extension treatment, and the rust prevention component concentration short-term distribution model is constructed, and this constructed rust prevention component concentration By conducting numerical analysis using Fick's diffusion difference equation with the short-term distribution model as an initial condition, the concentration distribution of rust-preventive components at any future point in the neutralized concrete is predicted, and the rust-prevention at the reinforcing bar position at the future point-in-time The success or failure of the atmosphere is evaluated.

  Next, with reference to FIGS. 9 to 11, the details of the construction process (S4) of the antirust component concentration short-term distribution model will be described based on the results of the antirust component short-term penetration confirmation test.

  Fig.9 (a) is explanatory drawing of the calculation process (S41) of examination total density | concentration (SIGMA) ρ, Comprising: The processing object by the concrete structure life extension process using the antirust repair material shown by FIG.5 (c) For neutralized concrete (see Fig. 6 (a)), a short-term penetration confirmation test of the rust-preventing component at the time when a four-month short-term penetration period has elapsed since the surface application of the repair layer (rust-preventing repair material) It is the graph which illustrated the measurement result of (S3).

  In addition, the measurement result of the short-term penetration confirmation test (S3) of the anticorrosive component shown in FIG. 9A is the same as the measurement result of FIG. The measurement results of the neutralization depth (average value) and the neutralization depth maximum value have a neutralization depth of 18 mm and a neutralization depth maximum value of 21 mm, as illustrated in FIG.

  In the construction process (S4) of this rust prevention component concentration short-term distribution model, first, from the measurement result of the short-term penetration confirmation test (S3) of the rust prevention component shown in FIG. Then, a study range D1 is set that covers a region deeper than the shallowest set depth, and a total concentration (hereinafter also referred to as “study total concentration”) Σρ of the rust preventive component that has permeated the study range D1 is obtained (S41). ).

  Here, in the case of the measurement result of the short-term penetration confirmation test (S3) of the rust preventive component shown in FIG. 9A, the shallowest set depth is 5 mm, and the entire range deeper than the shallowest set depth as the examination range D1 ( Specifically, eight (n = 8) depth elements xi (width Δx = 5 mm) existing up to a depth of 5 to 45 mm in FIG.

  Then, the examination total concentration Σρ (= ρ1 +... + Ρ8) of the anticorrosive component was 23.1 (≈5.06 + 3.85 + 4.28 + 5.85 + 2.79 + 0.83 + 0.27 + 0.14) kg / m 3.

  FIG. 9B is an explanatory diagram of the calculation process (S42) of the pre-penetrated uniform distribution concentration ρm, and is a graph assuming a state in which the total concentration Σρ of the antirust component is uniformly distributed in the pre-penetrated range D2. (Model diagram).

  As shown in FIG. 9 (b), after the calculation step (S41) of the examination total concentration Σρ, the amount equal to the examination total concentration Σρ is the deepest from the shallowest set depth to the anticorrosive component of the anticorrosive repair material. Assuming that each depth element xi in the existing penetration range D2 having the set depth as a range is uniformly distributed in a predetermined short-term penetration period, the total concentration Σρ to be examined is a depth in the existing penetration range D2. The value divided by the number m of the element xi is obtained as the already-permeated uniform distribution concentration ρm (S42).

  Here, as the deepest set depth of the existing penetration range D2, the boundary value on the deep side of the depth element xi including the maximum neutralization depth value measured in the step S2 (boundary depth) ) As the shallowest set depth of the already penetrated range D2, the shallower side of another depth element xi at a position shallower than the depth element xi including the maximum neutralization depth in the range Set each boundary value.

  For example, in the case of the measurement result of the short-term penetration confirmation test (S3) of the rust preventive component illustrated in FIG. 9A, the maximum depth of the penetration range D2 is within the maximum neutralization depth of 21 mm. The boundary value 25 mm on the deep side of the depth element xi (elements having a depth in the range of 20 to 25 mm) included in is set.

  Moreover, in the case of the measurement result of the short-term penetration confirmation test (S3) of the rust preventive component illustrated in FIG. 9A, as the shallowest set depth of the existing penetration range D2, for example, the neutralization depth maximum value 21 mm Of the depth element xi having a depth of 5 to 10 mm among the depth elements xi at a position shallower than the depth element xi (an element having a depth of 20 to 25 mm as a range) A boundary value of 5 mm was set.

  Therefore, as the already infiltrated range D2, there are four pieces existing within a range of depth 5mm (the shallowest set depth) to depth 25mm (the deepest set depth) (specifically, depths 5 to 25mm in the figure). A depth element xi (a range of width Δx = 5 mm) of minutes (m = 4) was set.

  Then, the permeation uniform distribution concentration ρm (= Σρ / m) of the rust preventive component was 5.78 (≈23.1 / 4) kg / m 3.

  However, when the penetration range D2 is set, when the maximum neutralization depth matches the boundary value between any adjacent depth element xn-1 and depth element xn, this neutralization depth Since the depth element xi containing the maximum depth value is unknown to any one of the depth elements xn-1 and xn, the value (depth) that matches the maximum neutralization depth value is set as the boundary value on the deep side. Up to (shallow) depth element xn-1 is set as including in the range of the existing penetration range D2, and the depth corresponding to the neutralization depth is set as the deepest setting depth. . For example, when the neutralization depth maximum value is 25 mm (see FIG. 13A), the existing penetration range D2 is within the range up to a depth element xi having a depth of 20 to 25 mm. In such a case, the deepest set depth is set to 25 mm.

  That is, the “depth element xi including the neutralization depth” related to the “pre-penetrated range D2” according to claim 3 or 5 is a case where the neutralization depth matches the boundary value of the depth element xi. Means a depth element xi having a value (depth) corresponding to the neutralization depth as a boundary value on the deep side.

  FIG. 10A is an explanatory diagram of the calculation step (S43) of the ideal uniform distribution concentration αm based on the initial mixed total concentration Σα, and the initial mixed total concentration Σα of the rust preventive component is equal to the ideal permeation range D3. It is a graph (model diagram) assuming a state of uniform distribution.

  As shown in FIG. 10 (a), after the step S42, the amount equal to the initial total concentration Σα of the anticorrosive component of the anticorrosive repair material ranges from the shallowest set depth to the deepest set depth. Assuming that each depth element xi within the ideal permeation range D3 is uniformly distributed over a predetermined short-term permeation period, the initial total concentration Σα is expressed as the number of depth elements xi within the ideal permeation range D3. The divided value k is obtained as an ideal uniform distribution concentration αm (S43).

  Here, as the shallowest set depth of the ideal penetration range D3, the depth of the surface of the repair layer made of the rust preventive repair material when the surface of the neutralized concrete is 0 mm deep is the deepest of the ideal penetration range D3. As the set depth, a boundary value on the deep side of the depth element xi that includes the maximum neutralization depth value measured in the step S2 in the range is set.

  For example, in the case of the measurement result of the short-term penetration confirmation test (S3) of the rust preventive component illustrated in FIG. 9A, the shallowest set depth of the ideal penetration range D3 is the thickness of the repair layer made of the rust preventive repair material. The depth element xi (depth 20 in FIG. 10A) includes a depth of -5 mm as 5 mm, and the deepest set depth of the ideal infiltration range D3 includes a neutralization depth maximum value of 21 mm. The boundary value 25 mm on the deep side of the element having a range of ˜25 mm was set.

  Therefore, the ideal permeation range D3 exists in a range from a depth of −5 mm (the shallowest set depth) to a depth of 25 mm (the deepest set depth) (specifically, from a depth of −5 to 25 mm in the figure). Six (k = 6) depth elements xi (the range of width Δx = 5 mm) are set.

  Then, the ideal uniform distribution concentration αm (= Σα / k) was 10.2 (≈61 ÷ 6) kg / m3 because the initial mixed total concentration Σα of the anticorrosive repair material was 61 kg / m3.

  However, when the ideal penetration range D3 is set, if the neutralization depth maximum value matches the boundary value between any adjacent depth element xn-1 and depth element xn, this neutralization depth Since the depth element xi containing the maximum depth value is unknown to any one of the depth elements xn-1 and xn, the value (depth) that matches the maximum neutralization depth value is set as the boundary value on the deep side. Up to (shallow) depth element xn-1 is set to be included in the range of the ideal infiltration range D3, and the depth corresponding to the neutralization depth is set as the deepest set depth. . For example, when the neutralization depth maximum value is 30 mm (see FIG. 13B), the ideal penetration range D3 is within the range up to the depth element xi having a depth of 25 to 30 mm. In such a case, the deepest set depth is set to 30 mm.

  That is, the “depth element xi including the neutralization depth” related to the “ideal penetration range D3” according to claim 1 or 4 is a case where the neutralization depth matches the boundary value of the depth element xi. Means a depth element xi having a value (depth) corresponding to the neutralization depth as a boundary value on the deep side.

  FIG. 10B is an explanatory diagram of the calculation process (S44) of the short-term permeability γ, and is a formula for obtaining the short-term permeability γ.

  As shown in FIG. 10 (b), after the step S43, for the rust preventive component that has penetrated into the ideal permeation range D3, the ratio of the pre-penetrated uniform distribution concentration ρm of the rust preventive component to the ideal uniform distribution concentration αm. The short-term penetration rate γ is obtained (S44). Then, the short-term penetration rate γ in the ideal penetration range D3 of the rust prevention component is 0.57 (≈5.78 / 10.2) for the rust prevention repair material.

  According to this result, the rust preventive repair material has an amount of Σρ corresponding to 57% of the initial mixed total concentration Σα in the short-term penetration period of 4 months, and at a uniform concentration ρm at least in the existing penetration range D2. It can be considered that it has permeated and moved in a distributed state.

  In view of the above, it is considered that the short-term permeability γ of the anticorrosive component can be estimated to be approximately 0.6.

  By the way, in the previous step of the calculation step (S44) of the short-term penetration rate γ of the rust preventive component, in the calculation step (S41) of the examination total concentration Σρ of the rust preventive component and the calculation step (S42) of the existing penetration uniform distribution concentration In some cases, the depth element xi in the range from the existing penetration range D2 to the depth of −5 to 5 mm is excluded, and the estimated value of the short-term penetration rate γ of the anticorrosive component is larger than 0.6. Presumed to be.

Therefore, the value of the short-term permeability γ of the rust preventive component may be set in the range of 0.6 to 0.7. If the can be omitted the step (except S4 6.) The S3 and S4 which is necessary for obtaining a short-term penetration of anticorrosive ingredients gamma.

  In addition, in the process of S44, when the short-term penetration rate γ of the rust-preventing component is obtained for two or more types of rust-preventing repair materials having different initial mixed total concentrations Σα, the average value of these short-term penetration rates γ is obtained. This may be the short-term penetration rate γ into the neutralized region of the neutralized concrete to be treated. For example, when the short-term penetration rate γ of the rust preventive component is obtained for two types of rust preventive repair materials, and γ = 0.57, 0.65, the average value of these values is 0.61 (= [ 0.57 + 0.65] / 2) may be set as the value of the short-term permeability γ of the neutralized region of the neutralized concrete to be treated.

  FIG. 11 is an explanatory diagram of the determination step (S45) of the antirust component concentration short-term distribution model, and in particular, FIG. 11A is a graph (model diagram) showing the antirust component concentration short-term distribution model. FIG. 11B is a graph (model diagram) in which the rust-preventive component concentration short-term distribution model shown in FIG.

  As shown in FIGS. 11 (a) and 11 (b), after the process of S44, a rust preventive component concentration short-term distribution model is determined (S45). Here, as shown in FIG. 11 (a), in the rust preventive component concentration short-term distribution model, the range from the surface of the repair layer made of the rust preventive repair material to the maximum neutralization depth is the ideal uniform distribution concentration αm. Modeled as a uniform distribution of rust-preventive components at a concentration equivalent to the short-term permeability γ × 100 (%) (hereinafter referred to as “determined uniform distribution concentration”) βm, and neutrality of the neutralization region The range of the non-neutralized region located in the deep layer part from the maximum value of the crystallization depth is modeled on the assumption that the rust preventive component is not penetrated uniformly (that is, the rust preventive component concentration is 0 kg / m 3).

  When the rust-preventive component concentration short-term distribution model shown in FIG. 11A is converted into a differential model, the result is as shown in FIG. 11B.

  According to FIG. 11B, in the differential model of the rust preventive component concentration short-term distribution model, the rust preventive component has a short-term permeability γ × 100 (%) of the ideal uniform distribution concentration αm in the range of the ideal permeation range D3. Corresponding concentration (hereinafter referred to as “deemed uniform distribution concentration”) is modeled as a uniform distribution at βm, and is not uniformly penetrated in a range deeper than the ideal penetration range D3 (that is, rust prevention) The component concentration is modeled as 0 kg / m3).

  Next, referring to FIG. 12, the prediction of the concentration distribution of rust-preventing components in neutralized concrete by numerical calculation of Fick's diffusion difference equation using the short-term distribution model of rust-preventing component concentration as an initial condition (S5), and this The success / failure judgment (S6) of the rust prevention atmosphere at the reinforcing bar position based on the predicted numerical calculation will be described.

  FIG. 12A is a diagram showing element division used for numerical calculation of Fick's diffusion difference equation, and FIG. 12B is a diagram of Fick constructed based on the element division of FIG. FIG. 12C shows an example of setting initial conditions for Fick's diffusion difference equation shown in FIG. 12B.

  In general, the penetration of penetrating components such as chloride ions and rust-preventing components into concrete is based on concentration difference diffusion, so Fick's second law (Formula 12-1) (see FIG. 12A). It is known that analysis can be performed by applying appropriate boundary conditions to

  Therefore, in this embodiment, in order to numerically analyze the diffusion phenomenon of infiltration components such as chloride ions and rust prevention components in the concrete, the one-dimensional difference method using the element division shown in FIG. Based on this, Fick's second law (diffusion equation) (Equation 12-1) is modeled, and using this modeled one-dimensional difference model equation (Fick's diffusion difference equation) (Equation 12-2), Predicts the concentration of object ions and rust inhibitor components.

  In addition, as shown in FIG.12 (b), I in Formula (12-2) is an antirust component density | concentration (kg / m3), D is an apparent diffusion coefficient (cm2 / s) of an antirust component. Represents.

  In Fick's diffusion difference equation (Equation 12-2) shown in FIG. 12B, the rust preventive component concentration short-term distribution model shown in FIG. 11B is applied as an initial condition (S5). Specifically, the rust preventive component concentration I shown in FIG. 12C is substituted as an initial value in the numerical analysis for predicting the rust preventive component concentration distribution using the equation (12-1).

  After substituting this initial value, the prediction of the concentration distribution of rust-preventing components in neutralized concrete is performed for any future time point, and Fick's diffusion difference equation is numerically calculated using an electronic computer such as a computer (S5). Based on the result of numerical calculation predicting the concentration distribution of the anticorrosive component, whether or not the anticorrosive atmosphere molar ratio, which is the molar concentration ratio of the anticorrosive component to the chloride ion concentration at the reinforcing bar position, is 0.8 or more. Is determined (S6 to S8).

  As for the numerical calculation method for predicting the chloride ion concentration at the reinforcing bar position at an arbitrary future time point, for example, “Numerical analysis by the difference method” described in Patent Document 1 and Non-Patent Document 1 described above. Conventional methods such as “salt penetration analysis of used concrete members” are used.

  In this determination (S8), if the molar ratio of the rust-proof atmosphere is 0.8 or more (S8: Yes), the rust-proof atmosphere is already formed at the reinforcing bar position in the neutralized concrete at any future time point. (S9) On the other hand, if the rust-proof atmosphere molar ratio is less than 0.8 (S8: No), the rust-proof atmosphere is not formed at the reinforcing bar position in the neutralized concrete at any future time point. Is determined (S11).

  As a result of this determination, when it is determined that the rust-proof atmosphere is already formed (S9), the life extension process by the repair layer of the rust-proof repair material used in the short-term penetration confirmation test in the step S3 is appropriate. (S10) On the other hand, if it is determined that the rust-proof atmosphere has not been formed (S11), repair of the rust-proof repair material used in the short-term penetration confirmation test in step S3 It can be determined that the life extension process by the layer is inappropriate (S12).

  By utilizing the short-term penetration characteristics of the rust-preventing component in such neutralized concrete, after confirming the rust-preventing component concentration distribution after the prescribed short-term penetration period has elapsed, the rust-preventing component concentration short-term distribution By constructing a model and using Fick's diffusion difference equation as the initial condition for this rust preventive component concentration short-term distribution model, it is possible to perform numerical calculations based on Fick's diffusion difference equation, so the future prediction of rust preventive component concentration distribution in neutralized concrete is more realistic It can be performed.

  In addition, in the construction of this short-term distribution model of rust-preventive components, the data necessary for setting the total concentration Σρ to be examined and the existing penetration range D2 is obtained by performing a short-term penetration confirmation test of rust-preventive components for a short period of about 4 months. As a result, it is possible to quickly take measures such as changing the initial total concentration Σα of rust-preventive ingredients as appropriate, and as a result, it is easy to select a quicker and more effective life extension treatment for neutralized concrete. It will be possible.

  FIG. 13 is a graph showing an example of a numerical analysis result in step S5 of the above-described rust prevention effect prior evaluation method, at the time when a repair layer (rust prevention repair material) is applied to the surface of neutralized concrete. Rust prevention component concentration short-term distribution model and numerical analysis results predicting the concentration distribution of rust prevention component in neutralized concrete at 1 year, 2 years, 3 years, and 10 years It is a comparison.

  Here, the numerical analysis shown in FIG. 13 shows that the initial concentration Σα of the antirust component of the antirust repair material is 60 kg / m 3, the rebar cover thickness is 35 mm, and the apparent diffusion coefficient of the concrete is 4 × 10 −8 cm 2 / s (value obtained from the above specification (when the water-cement ratio is W / C≈0.49)), the thickness of the anticorrosive repair material is 2.5 mm, and in particular, FIG. ) Is a neutralized concrete with a maximum neutralization depth of 25 mm, and FIG. 13B shows a neutralized concrete with a maximum neutralization depth of 30 mm. The rebar cover thickness of 35 mm is a value that is normally adopted for floor slabs.

  Also, in FIG. 13A, the difference model of the antirust component concentration short-term distribution model, which is the initial condition in Fick's diffusion difference equation, is the depth Δx = 5 mm of the depth element xi and the shallowest set depth of the ideal penetration range D3. Is 0 mm (surface of neutralized concrete), the maximum depth of the ideal penetration range D3 is 25 mm (the depth element xi of 20 to 25 mm including the maximum neutralization depth in the range) The boundary value on the deep side), and the assumed uniform distribution concentration βm = 3.8 kg / m3.

  In FIG. 13B, the difference model of the rust preventive component concentration short-term distribution model, which is the initial condition in Fick's diffusion difference equation, is the depth Δx = 5 mm of the depth element xi and the shallowest set depth of the ideal penetration range D3. Of the depth element xi in the range of 25 to 30 mm including 0 mm (surface of the neutralized concrete) and the deepest set depth of the ideal penetration range D3 being 30 mm (the neutralization depth maximum value is included in the range) The boundary value on the deep side) and the assumed uniform distribution concentration βm = 3.2 kg / m3.

  Then, using the differential model of the rust preventive component concentration short-term distribution model as an initial condition and numerical analysis (S5) using Fick's diffusion differential equation, one year from the time of this initial condition (rust preventive component concentration short-term distribution model) After 2 years, 3 years, and 10 years later, the concentration distribution of rust-preventive components for the ideal penetration range (neutralized region) and deeper regions (non-neutralized region) 13 are obtained as prediction curves for the concentration distribution of the anticorrosive components at the four types of future time points shown in FIG.

  According to the prediction curves of the rust inhibitor component concentration distribution at these four future time points, the rust inhibitor component concentration at the reinforcing bar position is 1.2 kg / m3 at one year later and 1 at two years later. .4 kg / m3, 1.5 kg / m3 after 3 years. Here, the concentration of the rust-preventing component at the reinforcing bar position has increased to a value that is almost close to the maximum concentration after 2 to 3 years, and when focusing on the concentration value after 1 year, it is 2 to 3 years. The value is close to the value at a later time.

  Therefore, under the conditions illustrated in FIG. 13, if the chloride ion concentration at the reinforcing bar position is within 1.4 kg / m 3, the molar ratio of the rust-proof atmosphere becomes 0.8 or more after about 2 years, It can be determined that the rust atmosphere is already formed.

  FIG. 14 shows that the rust-proof atmosphere is already formed two years after the surface of the rust-proof repair material (2.5 mm thick) is applied to the surface of the neutralized concrete using the conditions illustrated in FIG. The initial total concentration Σα of the rust-preventive component that is in the state and the chloride ion concentration that can form a rust-proof atmosphere at the reinforcing bar position (35 mm) in the neutralized concrete by the rust-preventive component of the initial total concentration Σα (It is called "rust prevention limit chloride ion density | concentration."), It has each shown about the case where the neutralization depth maximum value is 25 mm and 30 mm.

  Here, the graph shown in FIG. 14 shows a rust-proof atmosphere at the reinforcing bar position of the neutralized concrete by applying a life extension treatment by applying a repair layer of the rust-proof repair material to the surface of the neutralized concrete with a predetermined thickness. Is used as a determination chart (hereinafter referred to as “rust prevention component amount determination chart”) for determining an initial total concentration Σα of an appropriate rust prevention component with respect to the chloride ion concentration at the reinforcing bar position. It is done.

  The method for preparing this rust prevention component amount judgment chart includes the above-mentioned rust prevention effect advance evaluation method in part, and in this rust prevention effect advance evaluation method, the neutralization depth maximum value of neutralized concrete Is 25 mm or 35 mm, the rebar cover thickness is 35 mm, and the apparent diffusion coefficient of concrete is 4 × 10 −8 cm 2 / s (value obtained from the above specifications (when the water-cement ratio is W / C≈0.49)) The thickness of the antirust repair material is set to 2.5 mm.

  These various setting conditions include two types of maximum neutralization depth values of 25 mm and 30 mm, and the initial total concentration Σα of the anticorrosive component of the anticorrosive repair material changes to multiple values. Except for this, the setting conditions are the same as those shown in FIG.

  In addition, the difference model of the rust preventive component concentration short-term distribution model used as the initial condition in Fick's diffusion difference equation, which is used in the method of creating the rust preventive component amount determination chart, has a width Δx = 5 mm of the depth element xi, ideal penetration The shallowest set depth of the range D3 is 0 mm (surface of neutralized concrete), and the deepest set depth of the ideal penetration range D3 is 25 mm (20 to 25 mm including the maximum neutralized depth in the range) Boundary value on the deep side of the depth element xi) or 30 mm (boundary value on the deep side of the depth element xi in the range of 25 to 30 mm including the maximum neutralization depth in the range), The uniform distribution concentration βm is such that βm = 3.8 kg / m3 when the maximum neutralization depth is 25 mm, and βm = 3.2 kg / m3 when the maximum neutralization depth is 30 mm. Is built.

  This difference model is the same as that illustrated in FIG. 13 except that the difference model is constructed for two types of cases where the maximum value of the neutralization depth is 25 mm and 30 mm.

  These rust prevention component amount determination charts, for the case where the neutralization depth maximum value is 25 mm and 30 mm, the value of the initial mixed total concentration Σα of the rust prevention component of the rust prevention repair material is arbitrarily changed and substituted, A plurality of short-term distribution models of rust-preventive component concentrations with different initial mixed total concentrations Σα are constructed (S4), and numerical calculation of Fick's diffusion difference equation is performed using each rust-preventive component concentration short-term distribution model as an initial condition. The prediction of the concentration distribution of rust-preventing components in neutralized concrete after 2 years from the initial condition is executed using a computer such as a computer (S5). Obtain the predicted value of the component concentration, and set the chloride ion concentration at which the molar ratio of the rust-proof atmosphere is 0.8 to the predicted value of the rust-proof component concentration. Chloride ion concentration It is a plot.

  Moreover, in the rust prevention component amount determination chart, the approximate straight line (regression straight line by the least square method) shown therein has a neutralization depth maximum value of 25 mm and a neutralization depth maximum value of 30 mm. In this case, the boundary line indicating whether or not the initial total concentration Σα of the rust preventive component can form a rust preventive atmosphere with respect to the chloride ion concentration at the reinforcing bar position of the neutralized concrete It functions as a "rust effect boundary line").

  For example, the rust preventive component amount determination chart shown in FIG. 14 shows that the rust preventive atmosphere is in the region above the rust preventive effect boundary line at the future point of 2 years after the surface application of the repair layer (rust preventive repair material). While it can be determined that it has not been formed, it can be determined that the rust-proof atmosphere has already been formed if the region is below the rust-preventing effect boundary line.

  Here, according to FIG. 14, even if the maximum neutralization depth is different in the correlation (rust prevention effect boundary line) between the total concentration Σα of the rust prevention component and the rust prevention limit chloride ion concentration. It does not change so much, and the effect of the neutralization depth is considered to be extremely small in this correlation.

  Next, a method of using the determination chart of the initial input total concentration of the rust preventive component (hereinafter referred to as “rust preventive component amount determination chart”) will be described. First, before using this determination chart, the chloride ion concentration at the reinforcing bar position is measured for neutralized concrete that has been subjected to life extension treatment with a rust preventive repair material in advance.

  Then, read the value of the total concentration Σα of the anticorrosive component that intersects the measured value of the chloride ion concentration at the reinforcing bar position on the anticorrosive effect boundary line, and the initial value of the anticorrosive component is read above the read value If the total concentration is Σα, two years after the surface of the neutralized concrete is applied to the surface of the neutralized concrete with a thickness of 2.5 mm, the rust prevention material is rust-proof at the position of the rebar with a cover thickness of 35 mm. It can be determined that an atmosphere is formed.

  Sometimes, if the measured value of the chloride ion concentration measured in advance is smaller than the range indicated by the rust prevention component amount determination chart in FIG. Since it is formed at the reinforcing bar position, it is about the same as the minimum plot value of the rust prevention effect boundary line (neutralization depth maximum value 30 mm), specifically about 15 kg / m3 of the rust prevention component of the rust repair material. It is preferable to ensure the initial total concentration Σα.

  In addition, since the limit value of the initial contamination total concentration Σα of the anticorrosive repair material is about 90 kg / m 3, the value corresponding to the limit value of the initial contamination total concentration Σα (≈ If it exceeds 2.0 kg / m3), if the thickness of the repair layer made of the antirust repair material is 2.5 mm, a rustproof atmosphere cannot be formed at the reinforcing bar position. It is preferable to set the thickness of the repair layer made of the repair material to a value of 2.5 mm or more and create the above-described rust prevention component amount determination chart.

  According to the rust prevention effect prior evaluation method described above, the initial mixed total concentration Σα of the steel bridge RC floor slab and the RC hollow slab neutralized concrete according to the chloride ion concentration penetrating the reinforcing bar position By mixing the rust preventive component in the rust preventive repair material and applying it to the surface of the neutralized concrete, it is possible to efficiently and effectively realize the prevention of neutralization and the prevention of rebar corrosion.

  Specifically, the surface of the rust preventive repair material mixed with the appropriate amount of the rust preventive component as the initial mixed total concentration Σα is applied to the bottom surface of the neutralized RC slab whose deterioration level is in the progress stage or acceleration stage. By applying, the antirust component can be moved to the vicinity of the reinforcing bar in a short period of about 2 years, and an antirust atmosphere can be formed in a short time for the reinforcing bar in a corrosive environment. As a result, rebar corrosion can be prevented, and the rapid progress of deterioration of the RC floor slab can be suppressed.

  In addition, by using the above rust prevention component amount determination chart, the initial total concentration Σα of the rust prevention component mixed into the rust repair material penetrates into the neutralized concrete on the bottom surface of the RC slab. The chloride ion concentration can be appropriately selected according to the value of the chloride ion concentration, particularly the chloride ion concentration at the reinforcing bar position.

  Furthermore, the concrete structure life extension processing method can also be applied as a preventive countermeasure for concrete structures in the stage of progress. In addition, since the effect of this preventive countermeasure work is manifested in a short period of time, it is possible to give a wide range to the implementation time of the subsequent full-scale countermeasure work.

  In addition, since the rust preventive component penetrates in a short period of several months to several years, it is more efficient to determine the initial concentration Σα of the rust preventive component while confirming the penetration status of the rust preventive component.・ Effective measures can be implemented. In addition, the repair layer can suppress the intrusion of CO2, and can also suppress the progress of neutralization after repair.

  The present invention has been described based on the embodiments. However, the present invention is not limited to the above-described embodiments, and various improvements and modifications can be easily made without departing from the spirit of the present invention. It can be guessed.

For example, in this example, the “neutralization depth” described in the present invention has been described using the “neutralization depth maximum value”, but the “neutralization depth” according to the present invention is: The "neutralization depth" is not limited to the "maximum neutralization depth value", and the "neutralization depth" itself, which is an average value of measured values, may be used.

Claims (5)

This rust prevention component concentration prediction process includes a rust prevention component concentration prediction step for predicting the diffusion of rust prevention components for neutralized concrete whose surface is coated with a rust prevention repair material mixed with a rust prevention component as a repair layer. In the anti-rust effect pre-evaluation method to pre-evaluate the feasibility of forming a rust-proof atmosphere at the reinforcing bar position of the concrete structure by
The rust preventive component concentration prediction step performs numerical calculation of Fick's diffusion difference equation with the initial condition of the rust preventive component concentration short-term distribution model at the time when a predetermined short-term penetration period has elapsed since the surface application of the repair layer, It predicts the concentration distribution of rust-preventive components in neutralized concrete at any future time point,
Rust prevention component concentration short-term distribution model is
At the time when the specified short-term penetration period has elapsed since the surface application of the repair layer,
The amount of rust preventive component equal to the initial total concentration Σα ranges from the surface of the repair layer to the depth element xi including the neutralization depth measured using the core taken from the neutralized concrete to be repaired. When it is assumed that the distribution is uniform at each depth element xi within the ideal permeation range D3, the concentration of the rust preventive component of each depth element xi is the ideal uniform distribution concentration αm, and the ideal uniform distribution concentration αm. In addition, the neutralization depth measured using the predetermined short-term penetration rate γ or the neutralization depth measured using the core and the neutralization depth measured in the short-term penetration confirmation experiment of the anticorrosive component of the antirust repair material using the core As a uniform distribution concentration βm without observing the rust inhibitor concentration obtained by multiplying the short-term permeability γ determined based on the calculated value ,
The rust preventive component concentration is uniformly distributed at the above-mentioned uniform distribution concentration βm at each depth element xi in the ideal infiltration range D3, and at the depth element xi that is deeper than the ideal infiltration range D3. As the rust component is uniformly impregnated,
Rust prevention effect prior evaluation method characterized by being constructed.   It is assumed that the amount of rust preventive component equal to the initial total contamination concentration Σα is uniformly distributed in each depth element xi within the ideal permeation range D3 in the short-term permeation period, and the initial total contamination concentration Σα is the ideal concentration. The rust prevention effect prior evaluation method according to claim 1, wherein the ideal uniform distribution concentration αm is calculated by dividing by a number k of depth elements xi within the permeation range D3. The short-term penetration rate γ is calculated as a ratio of the already penetrated uniform distribution concentration ρm of the rust preventive component to the ideal uniform distribution concentration αm,
It is assumed that the ideal uniform distribution concentration αm is uniformly distributed in the short-term penetration period at each depth element xi within the ideal penetration range D3 in an amount of the rust preventive component equal to the initial mixed total concentration Σα. It is calculated by dividing the initial mixed total concentration Σα by the number k of depth elements xi within the ideal penetration range D3,
The pre-penetrated uniform distribution concentration ρm is measured in a short-term penetration confirmation experiment of the anti-rust component of the anti-rust repair material using the core from the shallowest set depth, with the amount of the anti-rust component equal to the total concentration Σρ considered. Assuming uniform distribution at each depth element xi in the existing penetration range D2 including the depth element xi including the oxidization depth, the total concentration Σρ to be examined is the depth in the existing penetration range D2. Calculated by dividing by the number m of elements xi,
The total concentration Σρ of the rust-preventing component is the short-term penetration of the rust-preventing component according to the distribution of the rust-preventing component concentration in the depth direction from the surface of the repairing layer at the time when the predetermined penetration test period has elapsed since the surface coating of the repairing layer. Measured by a confirmation test, and calculated from the result of measurement by summing up the rust preventive component concentration of each depth element xi in the examination range D1 including the depth below the shallowest set depth. Item 3. A method for evaluating the rust prevention effect in advance according to item 1 or 2. In the construction method of the antirust component concentration short-term distribution model for neutralized concrete used in the antirust effect prior evaluation method according to claim 1 or 2,
When a predetermined short-term penetration period has elapsed since the surface of the repair layer was applied, an amount of rust-preventive component equal to the initial total concentration Σα was collected from the neutralized concrete to be repaired from the surface of the repair layer. Rust preventive component concentration of each depth element xi when assuming uniform distribution in each depth element xi within the ideal penetration range D3 including the measured neutralization depth up to the depth element xi Is calculated as an ideal uniform distribution concentration αm,
At the time when a predetermined short-term penetration period has elapsed since the surface application of the repair layer, the ideal uniform distribution concentration αm is measured using a predetermined short-term penetration rate γ or the neutralization depth measured using the core and the core. Uniformity without seeing the concentration of anticorrosive component obtained by multiplying the short-term penetration rate γ determined based on the value calculated using the neutralization depth measured in the short-term penetration confirmation experiment of the anticorrosive component of the anticorrosive repair material Calculated as the distribution concentration βm,
At the time when a predetermined short-term penetration period has elapsed since the surface application of the repair layer, the rust preventive component concentration is uniformly distributed at each of the depth elements xi in the ideal penetration range D3 at the assumed uniform distribution concentration βm, In addition, in the depth element xi deeper than the ideal permeation range D3, a rust-preventive component concentration short-term distribution model is constructed assuming that the rust-preventive component is not uniformly permeated. Rust component concentration short-term distribution model construction method. The short-term penetration rate γ is calculated as a ratio of the already penetrated uniform distribution concentration ρm of the rust preventive component to the ideal uniform distribution concentration αm,
It is assumed that the ideal uniform distribution concentration αm is uniformly distributed in the short-term penetration period at each depth element xi within the ideal penetration range D3 in an amount of the rust preventive component equal to the initial mixed total concentration Σα. It is calculated by dividing the initial mixed total concentration Σα by the number k of depth elements xi within the ideal penetration range D3,
The pre-penetrated uniform distribution concentration ρm is within the pre-penetrated range D2 in which the amount of the rust preventive component equal to the examined total concentration Σρ ranges from the shallowest set depth to the depth element xi including the neutralization depth. Assuming a uniform distribution at each depth element xi, the calculated total concentration Σρ is divided by the number m of depth elements xi within the already infiltrated range D2,
The total concentration Σρ of the rust-preventing component is the short-term penetration of the rust-preventing component according to the distribution of the rust-preventing component concentration in the depth direction from the surface of the repairing layer at the time when the predetermined penetration test period has elapsed since the surface coating of the repairing layer. Measured by a confirmation test, and calculated from the result of measurement by summing up the rust preventive component concentration of each depth element xi in the examination range D1 including the depth below the shallowest set depth. Item 5. A method for constructing a short-term distribution model of rust-preventive component concentration of neutralized concrete according to Item 4.