JP2015094650A - Method for evaluating salt content permeation amount in concrete - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a simple method for evaluating a salt content permeation amount in concrete having versatility and capable of accurately evaluating the salt content permeation amount even when a surface impregnation material is coated on concrete.SOLUTION: A surface layer part sample 3S containing a portion impregnated and the portion not impregnated with a surface impregnation material A from concrete 1 coated with the surface impregnation material A on its surface, and a deep layer part sample 4S composed of only the portion not impregnated with the surface impregnation material A are collected. Diffusion coefficients D', Dc of chloride ions of the samples 3S, 4S are calculated by an electrophoresis or diffusion cell method. An equation (2) is derived in consideration of an equivalence covering by the surface impregnation material A for the solution of an equation (1) of a diffusion equation of Fick with respect to the surface layer part sample 3S. An apparent equivalence covering increment S is calculated by equation (4) derived from the equation (2) and the equation (3). A salt content impregnation amount is evaluated by a curve which allows the curve of the equation (1) substituting the diffusion coefficient Dc to move in a minus direction by the increment S by a x coordinate.

Description

  The present invention relates to a method for estimating the amount of salt penetration in concrete. More specifically, the present invention is capable of accurately estimating the amount of salt penetration even when a surface impregnating material such as silane or silicate is applied to concrete. The present invention relates to a simple and easy estimation method.

  In concrete structures subject to salt damage, various surface coating methods are applied as countermeasures. In this method, organic materials and inorganic materials are mainly used as surface coating materials, but in recent years, surface impregnated materials have attracted attention as materials that are inexpensive and have excellent workability and can suppress the penetration of chloride ions. Yes. Surface impregnating materials are roughly classified into silane-based (water-repellent) and silicate-based (non-water-repellent). Regarding the amount of salt penetration in concrete coated with a silane-based surface impregnated material, the salt content measured by an electron beam microanalyzer (hereinafter referred to as EPMA) using a concrete sample coated with the surface impregnated material and infiltrated with salt. In the regression analysis for the concentration distribution, a method has been proposed in which the diffusion coefficient of the concrete impregnated with the silane-based surface impregnated material and the non-impregnated part are obtained, and the salinity permeation amount is estimated using these. Patent Document 1).

  In this proposed estimation method, the diffusion coefficient of concrete chloride ions in the surface impregnated portion impregnated with the silane-based surface impregnated material and the internal unimpregnated portion not impregnated with the surface impregnated material is measured by EPMA. Obtained by regression analysis for the salinity concentration distribution, separately grasp the impregnation depth of the surface impregnated material, and estimate the salt permeation amount using these. Therefore, this estimation method has a problem that the impregnation depth Cs of the surface impregnation material must be obtained. Here, since the portion impregnated with the silane-based surface impregnating material can be visually confirmed as a water-repellent layer, it is relatively easy to grasp the impregnation depth. However, when a silicate-based surface impregnating material is used, the surface impregnating material reacts with calcium hydroxide in the concrete and solidifies, or the surface impregnating material itself solidifies. The impregnation depth of the surface impregnating material cannot be simply grasped. In addition, this method cannot be applied to a concrete sample in which the salt content has not penetrated into the concrete not impregnated with the surface impregnating material because the diffusion coefficient of the concrete in the unimpregnated portion cannot be obtained. there were.

  In addition, the diffusion coefficient of chloride ions in the portion impregnated with the surface impregnating material is currently estimated from advanced analysis results by EPMA. Therefore, there is a problem that it takes a great deal of cost and labor to estimate the amount of salt penetration. In addition, for existing concrete already infiltrated with salt, the regression analysis on the salt concentration distribution measured by EPMA cannot distinguish the amount of salt already infiltrated from the amount of salt infiltrated after applying the surface impregnating material. There was a problem that the chloride ion diffusion coefficient of the portion impregnated with the surface impregnating material could not be obtained.

Hirokazu Tanaka, two others, “Study on prediction method of chloride ion permeation of concrete using silane surface impregnating material”, published by Japan Society for Materials Science, repair, reinforcement and upgrade papers for concrete structures, Volume 12, November 2012, P439-444

  The purpose of the present invention is to have a high versatility that can accurately estimate the amount of salt infiltration even when a surface impregnation material such as silane or silicate is applied to concrete, and simple salt infiltration. It is to provide a method for estimating quantity.

Ｃ（ｘ、ｔ）：コンクリート表面からの深さｘ（ｍｍ）、時刻ｔ（年）における塩化物イオン濃度（ｋｇ／ｍ³）
Ｄ：コンクリートの塩化物イオンの拡散係数（ｍｍ²／年）
Ｃ₀：コンクリート表面における塩化物イオン濃度（ｋｇ／ｍ³）
Ｃ’：表層部サンプルの厚さ（ｍｍ）
Ｃｃ：表層部サンプルでの表面含浸材が含浸していない部分の厚さ（ｍｍ）
Ｃｓ：表層部サンプルでの表面含浸材が含浸した部分の厚さ（ｍｍ）
Ｄｓ：表層部サンプルでの表面含浸材が含浸した部分の拡散係数（ｍｍ²／年）
ｅｒｆ：誤差関数 In order to achieve the above object, the method for estimating the amount of salt penetration in concrete according to the present invention comprises a surface layer portion including a portion impregnated with a surface impregnated material and a portion not impregnated from the concrete coated with a surface impregnated material. A sample and a deep layer sample consisting only of a portion not impregnated with the surface impregnating material are collected, and a diffusion coefficient D ′ of chloride ions of the surface layer sample and a diffusion coefficient of chloride ions of the deep layer sample are collected. Dc is calculated by electrophoresis or diffusion cell method, and formula (2) is derived for the surface layer sample by taking into account the equivalent fogging by the surface impregnating material for the solution of Fick's diffusion equation of formula (1). Then, an apparent fog increase S is calculated from the equation (4) derived from the equations (2) and (3), and a curve is calculated by substituting the diffusion coefficient Dc for D in the equation (1). The curve is moved in the negative direction only by the x-coordinate fog increase S apparent has, and estimates the salt penetration amount at any time in any depth position from the surface of the concrete.

C (x, t): depth from concrete surface x (mm), chloride ion concentration at time t (year) (kg / m ³ )
D: Diffusion coefficient of chloride ion in concrete (mm ² / year)
C ₀ : chloride ion concentration on the concrete surface (kg / m ³ )
C ′: Surface layer sample thickness (mm)
Cc: Thickness (mm) of the surface impregnated portion of the surface layer sample not impregnated
Cs: Thickness (mm) of the portion impregnated with the surface impregnation material in the surface layer sample
Ds: Diffusion coefficient of the portion impregnated with the surface impregnating material in the surface layer sample (mm ² / year)
erf: error function

Ｃ（ｘ、ｔ）：コンクリート表面からの深さｘ（ｍｍ）、時刻ｔ（年）における塩化物イオン濃度（ｋｇ／ｍ³）
Ｄ：コンクリートの塩化物イオンの拡散係数（ｍｍ²／年）
Ｃ₀：コンクリート表面における塩化物イオン濃度（ｋｇ／ｍ³）
Ｃ’：表層部サンプルの厚さ（ｍｍ）
Ｃｃ：表層部サンプルでの表面含浸材が含浸していない部分の厚さ（ｍｍ）
Ｃｓ：表層部サンプルでの表面含浸材が含浸した部分の厚さ（ｍｍ）
Ｄｓ：表層部サンプルでの表面含浸材が含浸した部分の拡散係数（ｍｍ²／年）
ｅｒｆ：誤差関数 Another method for estimating the amount of salt penetration in the concrete of the present invention is a surface layer sample containing a portion impregnated with the surface impregnated material and a portion not impregnated from the concrete coated with the surface impregnated material. A deep layer sample consisting only of a portion not impregnated with the surface impregnating material, and a diffusion coefficient D ′ of chloride ions of the surface layer sample and a diffusion coefficient Dc of chloride ions of the deep layer sample are obtained. Calculated by electrophoresis or diffusion cell method, and for the surface layer sample, formula (2) is derived in consideration of the equivalent fogging by the surface impregnating material for the solution of Fick's diffusion equation of formula (1), The apparent fog increase amount S is calculated by the equation (4) derived from the equations (2) and (3), and the thickness Cs of the portion impregnated with the surface impregnation material in the surface layer portion is calculated as the surface impregnation. When the material is a material having a water repellent effect, it is grasped by measuring the thickness of the water repellent layer in the surface layer sample, and when the surface impregnated material is a material having no water repellent effect, the surface layer Based on the results of hardness measurement in the surface sample, and substituting the grasped thickness Cs into the equation (4), the diffusion coefficient of chloride ions in the portion impregnated with the surface impregnated material in the surface layer sample Ds is calculated, and the equation (1) is applied to the two-layer model of the concrete impregnated with the surface impregnating material and the concrete not impregnated with the equation (5) or (6). The salinity permeation amount at an arbitrary time of the position is estimated.

C (x, t): depth from concrete surface x (mm), chloride ion concentration at time t (year) (kg / m ³ )
D: Diffusion coefficient of chloride ion in concrete (mm ² / year)
C ₀ : chloride ion concentration on the concrete surface (kg / m ³ )
C ′: Surface layer sample thickness (mm)
Cc: Thickness (mm) of the surface impregnated portion of the surface layer sample not impregnated
Cs: Thickness (mm) of the portion impregnated with the surface impregnation material in the surface layer sample
Ds: Diffusion coefficient of the portion impregnated with the surface impregnating material in the surface layer sample (mm ² / year)
erf: error function

  According to the former method for estimating the amount of salt infiltration of the present invention, the surface layer sample and the deep layer sample collected from the concrete coated with the surface impregnating material, based on the test result of the electrophoresis method or the diffusion cell method, The apparent diffusion coefficient D ′ of the chloride ions of the surface layer sample and the apparent diffusion coefficient Dc of the chloride ions of the deep layer sample are calculated, and these diffusion coefficients D ′, Dc and the known sample data of the surface layer sample are calculated. Based on the thickness C ′ and the equations (1), (2), (3), and (4), the salinity at an arbitrary time at an arbitrary depth position from the surface of the concrete coated with the surface impregnating material. The amount of penetration can be estimated. In this estimation method, it is not necessary to measure the thickness Cs (that is, the impregnation depth Cs) of the portion impregnated with the surface impregnation material in the surface layer sample. Therefore, not only a material having a water repellent effect such as a silane surface impregnating material, but also a surface of a material having no water repellent effect such as an acid salt system in which the impregnation depth Cs is difficult to grasp easily. Even when the impregnating material is applied, the amount of salt permeation can be estimated easily and with high versatility. Since it is not necessary to perform advanced salt analysis by EPMA, the amount of salt infiltration can be estimated easily and at low cost.

  According to the latter method for estimating the amount of salt infiltration of the present invention, the surface layer sample and the deep layer sample collected from the concrete coated with the surface impregnating material, based on the test result of the electrophoresis method or the diffusion cell method, The apparent diffusion coefficient D ′ of chloride ions of the surface layer sample and the apparent diffusion coefficient Dc of chloride ions of the deep layer sample were calculated, and the surface obtained by using these diffusion coefficients D ′ and Dc and the surface layer sample Thickness Cs impregnated by the impregnating material (that is, impregnation depth Cs) and other known data thickness C ′ of the surface layer sample, and equations (1), (2), (3), (4) Based on the equations (5) and (6), the amount of salt infiltration at an arbitrary time at an arbitrary depth position can be estimated from the surface of the concrete coated with the surface impregnating material. In this estimation method, the thickness Cs (that is, the impregnation depth Cs) of the portion into which the surface impregnation material has permeated is grasped by actual measurement from the surface layer sample, so that the impregnation depth Cs can be grasped with higher accuracy. Thereby, improvement of the estimation accuracy of the amount of salt permeation can be expected, and it has high versatility applicable to any surface-impregnated material including silane-based and silicate-based materials. Since it is not necessary to perform advanced salt analysis by EPMA, the amount of salt infiltration can be estimated easily and at low cost.

It is a flowchart which illustrates the procedure of the estimation method of the salt penetration amount of this invention. It is explanatory drawing which illustrates the sample extract | collected from concrete. It is a graph which illustrates the relationship between the depth position from the surface in a surface layer part sample, and chloride ion content. It is a graph which illustrates the relationship between the depth position in a deep layer part sample, and chloride ion content. It is a graph which illustrates the relationship between the depth position in the concrete which considered the equivalent fog by the surface impregnation material, and the amount of chloride ions. It is a flowchart which illustrates the procedure of the estimation method of another salt penetration amount of this invention. It is a graph which illustrates the relationship between the depth position from the surface in the concrete by the two-layer model of the concrete which the surface impregnation material impregnated, and the concrete which is not impregnated, and the amount of chloride ions.

  The method for estimating the amount of salt infiltration in the concrete of the present invention is based on the surface of concrete under the influence of salt, such as a concrete structure in a coastal area or a concrete structure in an area where an antifreezing agent is applied. When the impregnating material is applied, the chloride ion concentration C (which is a function of position and time) at an arbitrary time position t at an arbitrary depth position x is estimated from the surface of the concrete. The arbitrary time t is, for example, an elapsed time after applying the surface impregnating material.

  Hereinafter, the method for estimating the amount of salt penetration of the present invention will be described based on the embodiment shown in the drawings. For example, when a surface impregnating material is applied to the surface of new concrete that has not yet permeated salt, the amount of salt permeation is estimated by the procedure illustrated in FIG.

  In step 1, the concrete core 2 is taken out from the concrete 1 of the concrete structure to which the surface impregnating material A is applied, as illustrated in FIG. The concrete core 2 includes only a surface layer portion 3 including a portion impregnated with the surface impregnating material A (thickness Cs) and a portion not impregnated (thickness Cc), and a portion not impregnated with the surface impregnating material A. It is taken out with a thickness having the deep layer portion 4 to be formed. Next, a surface layer sample 3 </ b> S (thickness C ′ = Cs + Cc) composed of the surface layer portion 3 and a deep layer sample 4 </ b> S composed of the deep layer portion 4 are collected from the concrete core 2.

In step 2, the apparent diffusion coefficient D ′ of chloride ions in the surface layer sample 3S and the apparent diffusion coefficient Dc of chloride ions in the deep layer sample 4S are calculated using the collected samples 3S and 4S. The apparent diffusion coefficients D ′ and Dc in each sample are the correction coefficient k _{1 to} the effective diffusion coefficient De ′ of the surface layer sample 3S and the effective diffusion coefficient Dec of the deep layer sample 4S obtained by the electrophoresis method or the diffusion cell method. · k ₂ is calculated by multiplying the. That is, D ′ = De ′ × k ₁ · k ₂ and Dc = Dec × k ₁ · k ₂ . The correction coefficients k ₁ and k ₂ are coefficients relating to the balance of chloride ions on the concrete surface and the phenomenon of chloride ion immobilization in cement hydrate, and are effective diffusion coefficients obtained from electrophoresis or diffusion cell methods. Is a coefficient for correcting the apparent diffusion coefficient.

  The electrophoresis method is a method described in the 2010 Standard Specification for Concrete “Standards”, Japan Society of Civil Engineers, and related standards (Japan Society of Civil Engineers). The diffusion cell method is a method described in “Trends in Test Methods for Establishment and Standardization of Chloride Ion Diffusion Coefficient Test Methods for Concrete” (published September 9, 2003, edited by the Japan Society of Civil Engineers). The diffusion cell method is a test method using a cell similar to the electrophoresis method to obtain a diffusion coefficient using only a concentration gradient as a driving force without applying an electric field.

  In Step 3, the apparent fog increase amount S is calculated by regarding the effect of reducing the chloride ion penetration of the concrete impregnated with the surface impregnated material A as the increase in the fog of the concrete not impregnated with the surface impregnated material. Here, the above equation (1) is known as a solution to Fick's diffusion equation for estimating the amount of salt permeation in concrete. Therefore, when the data of the surface layer sample 3S is substituted into the equation (1), the left side of the equation (2) is obtained. On the other hand, the effect of reducing the penetration of chloride ions in the concrete impregnated with the surface impregnated material A is regarded as an increase in the fog of the concrete 1, and the surface sample 3S is impregnated with the surface impregnated material A in consideration of equivalent fog. It can be considered as a model divided into two layers of (thickness Cs) and an unimpregnated portion (thickness Cc). Then, if the data corresponding to each layer is substituted into the equation (1), the right side of the equation (2) is obtained, and the left side and the right side are equal, and the equation (2) is established.

By arranging the equations (2) and (3), the above equation (4) is derived. Equation (4) represents an apparent fog increase S calculated by regarding the effect of reducing the penetration of chloride ions in the concrete impregnated with the surface impregnating material A as the fog increase of the concrete 1. In this case, the equivalent fogging Ci is Ci = Cs × (√Dc / √Ds), and Ci = S + Cs.

  FIG. 3 conceptually shows the equation (2). That is, for the surface layer sample 3S, the estimation formula for the amount of chloride permeation is a curve governed by the diffusion coefficient D ′ indicated by the broken line, but the diffusion coefficient Ds indicated by the solid line is impregnated by the surface impregnated material A. It can be regarded that the curve is dominated by the diffusion coefficient Dc indicated by the solid line in the portion not impregnated with the surface impregnated material A. Here, the diffusion coefficient Dc is known because it is grasped as illustrated in FIG. 4 by electrophoresis or diffusion cell method using the deep layer sample 4S. The diffusion coefficient D ′ is known by the electrophoresis method or the diffusion cell method using the surface layer sample 3S. The thickness C ′ of the surface layer sample 3S is also known. Therefore, the apparent fog increase S due to the surface impregnated material A can be calculated by substituting these data into the equation (4).

  In step 4, the chloride ion concentration C at an arbitrary time t is estimated at an arbitrary depth position x from the surface of the concrete 1 by the equation (1). Here, if the effect of reducing the penetration of chloride ions by the surface impregnating material A is considered as an increase in fogging of the concrete 1, the chloride ion concentration C when the surface impregnating material A is applied to the surface of the concrete 1 is shown in FIG. Can be represented by a curve C (x + S, t) indicated by a solid line. A curve C (x, t) indicated by a broken line in FIG. 5 indicates a chloride ion concentration in the concrete 1 when the surface impregnating material A is not applied. That is, the curve C (x + S, t) is the curve C (x, t) moved in the negative direction by the apparent fog increase amount S by the x coordinate. The diffusion coefficient Dc in the curve (x, t) is already known. Therefore, by using the curve (x + S, t) obtained by sliding the curve (x, t) by the apparent fog increase S in the negative direction on the x coordinate, any arbitrary depth position x from the surface of the concrete 1 is used. The chloride ion concentration C at time t can be estimated.

  In the estimation method of this embodiment, it is not necessary to actually measure and grasp the thickness Cs of the portion impregnated with the surface impregnating material A using the surface layer sample 3S. Therefore, even when the surface-impregnated material A, which is difficult to grasp the thickness Cs of the portion impregnated with the surface-impregnated material A (that is, the impregnation depth Cs), is applied to the surface of the concrete 1, The chloride ion concentration C can be estimated easily and accurately. Similarly, when the silane-based surface impregnation material A is applied to the surface of the concrete 1, the chloride ion concentration C can be estimated without measuring the impregnation depth Cs. Further, since it is not necessary to perform advanced salt analysis by EPMA, the chloride ion concentration C can be estimated simply and at low cost.

  Next, another embodiment of the method for estimating the salt penetration amount will be described. For example, when the surface impregnating material A is applied to the surface of the existing concrete 1 in which salt has already permeated, the amount of salt infiltration is estimated by the procedure illustrated in FIG.

  Steps 1 to 3 are the same as in the above-described embodiment. In step 1, the surface layer sample 3 </ b> S and the deep layer sample 4 </ b> S are collected from the existing concrete 1 in which the salt has already permeated. In step 4, it is selected whether the surface impregnating material A applied to the surface of the concrete 1 is silane or silicate.

  When the silane-based surface impregnating material A is applied, as step 5A, the thickness of the water repellent layer of the surface layer sample 3S is measured, and the thickness Cs (impregnation depth Cs) of the impregnated portion is measured. To grasp. Since the silane-based surface impregnated material A has water repellency, after the surface layer sample 3S is vertically divided and immersed in water, the thickness of the water repellent portion of the divided surface is measured with a measure or the like. The thickness Cs of the impregnated part is grasped.

  When the silicate-based surface impregnating material A is applied, as step 5B, the surface layer sample 3S is measured for hardness, and the impregnated portion thickness Cs (impregnation depth Cs) is determined based on the measurement result. To grasp. When the silicate-based surface impregnating material A is impregnated, the surface structure is densified. Therefore, using this property, the position where the hardness is greatly changed is not impregnated with the portion impregnated with the surface impregnating material. It can be regarded as a boundary with a part. For example, the surface layer sample 3S is vertically divided and the measurement position is sequentially changed in the depth direction from the surface side to perform the Vickers hardness test, and the thickness Cs of the impregnated portion is grasped from the result. The hardness measurement is not limited to the Vickers hardness test, and other hardness measurement methods can also be used.

  In Step 6, the diffusion coefficient Ds is calculated by substituting the thickness Cs of the impregnated portion grasped in Step 5A or Step 5B into the equation (4). Since the apparent fog increase amount S and the diffusion coefficients D ′ and Cc are known in the equation (4), the diffusion coefficient Ds can be calculated by substituting the thickness Cs of the impregnated portion.

  When equation (1) is applied to a two-layer model of a portion impregnated with surface impregnated material A (impregnation depth Cs) and a portion not impregnated, equations (5) and (6) can be derived. . FIG. 7 conceptually shows the equations (5) and (6). The chloride ion concentration C when the surface impregnating material A is applied to the surface of the concrete 1 can be expressed by a curve C (x, t) shown by a solid line in FIG. A curve indicated by a broken line in FIG. 7 indicates a chloride ion concentration C in the concrete 1 when the surface impregnating material A is not applied. The curve C (x, t) is a curve governed by the diffusion coefficient Ds in the portion impregnated with the surface impregnating material A (0 ≦ x ≦ Cs), that is, from the surface of the concrete 1 using the equation (6). The chloride ion concentration C at an arbitrary time t at the depth position x can be estimated. In a portion not impregnated with the surface impregnated material A (Cs ≦ x), a curve governed by the diffusion coefficient Dc, that is, an arbitrary time t at an arbitrary depth position x from the surface of the concrete 1 using the equation (5). The chloride ion concentration C can be estimated.

  In the estimation method of this embodiment, since the thickness Cs of the portion impregnated with the surface impregnating material A in the surface layer portion 3 is measured and grasped by the surface layer portion sample 3S, the thickness Cs (that is, the impregnation depth Cs) is obtained. It can be grasped with higher accuracy and an improvement in the estimation accuracy of the amount of salt infiltration can be expected. Moreover, since the amount of salt permeation can be estimated for any surface impregnated material E of silane type or silicate type, it has high versatility. The present invention can be applied not only to the existing concrete 1 but also to the new concrete 1. Since it is not necessary to perform advanced salt analysis by EPMA, the amount of salt infiltration can be estimated easily and at low cost.

1 Concrete 2 Concrete Core 3 Surface Layer 3S Surface Layer Sample 4 Deep Layer 4S Deep Layer Sample A Surface Impregnating Material

Claims (4)

A surface layer sample including a portion impregnated with the surface impregnated material and a portion not impregnated from concrete coated with a surface impregnated material, and a deep layer sample consisting only of a portion not impregnated with the surface impregnated material And the diffusion coefficient D ′ of chloride ions of the surface layer sample and the diffusion coefficient Dc of chloride ions of the deep layer sample are calculated by electrophoresis or diffusion cell method. The equation (2) is derived for the solution of Fick's diffusion equation of the equation (1) in consideration of the equivalent fogging by the surface impregnated material, and the equation (4) derived from the equations (2) and (3) An apparent fog increase S is calculated, and a curve obtained by substituting the diffusion coefficient Dc for D in the equation (1) is moved in the negative direction by the x coordinate by the calculated apparent fog increase S. Estimation method of salt permeation amount in concrete and estimates the salt penetration amount at any time in any depth position from the surface in the serial concrete.

C (x, t): depth from concrete surface x (mm), chloride ion concentration at time t (year) (kg / m ³ )
D: Diffusion coefficient of chloride ion in concrete (mm ² / year)
C ₀ : chloride ion concentration on the concrete surface (kg / m ³ )
C ′: Surface layer sample thickness (mm)
Cc: Thickness (mm) of the surface impregnated portion of the surface layer sample not impregnated
Cs: Thickness (mm) of the portion impregnated with the surface impregnation material in the surface layer sample
Ds: Diffusion coefficient of the portion impregnated with the surface impregnating material in the surface layer sample (mm ² / year)
erf: error function A surface layer sample including a portion impregnated with the surface impregnated material and a portion not impregnated from concrete coated with a surface impregnated material, and a deep layer sample consisting only of a portion not impregnated with the surface impregnated material And the diffusion coefficient D ′ of chloride ions of the surface layer sample and the diffusion coefficient Dc of chloride ions of the deep layer sample are calculated by electrophoresis or diffusion cell method. The equation (2) is derived for the solution of Fick's diffusion equation of the equation (1) in consideration of the equivalent fogging by the surface impregnated material, and the equation (4) derived from the equations (2) and (3) The apparent fog increase S is calculated, and the thickness Cs of the surface impregnated material impregnated in the surface layer portion is determined. If the surface impregnated material is a material having a water repellent effect, the water repellent property of the surface layer sample is determined. Layered By measuring the thickness, if the surface impregnated material is a material that does not have a water repellent effect, the thickness Cs is determined based on the result of hardness measurement on the surface layer sample. By substituting into the equation (4), the diffusion coefficient Ds of the chloride ion of the portion impregnated with the surface impregnation material in the surface layer sample is calculated, and the equation (1) is impregnated with the concrete impregnated with the surface impregnation material. In the concrete characterized by estimating the amount of salt infiltration at an arbitrary time at an arbitrary depth position from the surface of the concrete according to the equation (5) or (6) applied to a two-layer model of non-concrete A method for estimating the amount of salt penetration.

C (x, t): depth from concrete surface x (mm), chloride ion concentration at time t (year) (kg / m ³ )
D: Diffusion coefficient of chloride ion in concrete (mm ² / year)
C ₀ : chloride ion concentration on the concrete surface (kg / m ³ )
C ′: Surface layer sample thickness (mm)
Cc: Thickness (mm) of the surface impregnated portion of the surface layer sample not impregnated
Cs: Thickness (mm) of the portion impregnated with the surface impregnation material in the surface layer sample
Ds: Diffusion coefficient of the portion impregnated with the surface impregnating material in the surface layer sample (mm ² / year)
erf: error function   The said concrete is a concrete which salt content does not osmose | permeate, The estimation method of the salt osmosis | permeation amount in concrete of Claim 1 or 2.   The method for estimating a salt penetration amount in concrete according to claim 1 or 2, wherein the concrete is an existing concrete in which salt has already permeated.

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