JP2015034119A - Surface finishing method of concrete structure, and concrete structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a surface finishing method of a concrete structure which suppresses cracking and achieves good appearance, and a concrete structure.SOLUTION: A surface finishing method of a concrete structure includes the steps of: placing ultra-low shrinkage concrete prepared by using as main components, cement, a coarse aggregate and a fine aggregate using limestone as their raw material, and water, and mixing an admixture having a viscosity of 10-200 mPa s (at 20°C) so that the binder to water ratio is 1.54-3.33 and the dry shrinkage rate at a material age of 6 months is 1.5×10or less; and coating an anionic surfactant on the surface of the placed ultra-low shrinkage concrete.

Description

  The present invention relates to a surface finishing method for a concrete structure and a concrete structure.

In general, ordinary concrete shrinks when it is dried after being hardened, so numerous fine cracks are generated on the surface. Therefore, in order to prevent cracking due to drying shrinkage of concrete, development of ultra-low shrinkage concrete as shown in Non-Patent Document 1 below is underway. This ultra-low shrinkage concrete uses limestone as a coarse aggregate, and uses a shrinkage reducing agent, a high-performance AE water reducing agent and dihydrate gypsum as an admixture. It is disclosed that the drying shrinkage strain at a material age of 180 days (6 months) can be about 200 × 10 ^{−6 to} 500 × 10 ⁻⁶ .

  In order to prevent cracking of concrete, a paraffin-based coating type curing agent may be applied to the surface of ultra-low shrinkage concrete.

Inagaki et al., "Study on cracking suppression effect of dry shrinkage 200μ class ultra low shrinkage concrete (Part 1. Basic physical properties of ultra low shrinkage concrete)", Annual Meeting of the Architectural Institute of Japan (Hokuriku), September 2010, p. 917-918.

However, although the ultra-low shrinkage concrete described in Non-Patent Document 1 is superior in dry shrinkage performance compared to general concrete, the dry shrinkage strain is still 200 μ class (about 200 × 10 ⁻⁶ . Since the limit is about 2 × 10 ^{−4 in} terms of rate, there is a limit to the crack suppression effect.

  In addition, when the curing agent is not applied to the surface of the placed ultra-low-shrinkage concrete and when the paraffin-based coating type curing material is applied, unevenness is generated on the surface, resulting in a smooth surface finish. There is a problem that the finishing accuracy is poor.

  Then, this invention is made | formed in view of the said situation, While providing a crack, the surface finishing method and concrete structure of a concrete structure with a favorable external appearance are provided.

In order to achieve the above object, the present invention employs the following means.
That is, the surface finishing method of the concrete structure according to the present invention is mainly made of cement, coarse aggregate, fine aggregate and water, and limestone is used as a raw material for the coarse aggregate and the fine aggregate, An admixture with a viscosity of 10 to 200 mPa · s (20 ° C.) is blended, the binder water ratio is 1.54 to 3.33, and the drying shrinkage at 6 months of age is 1.5 × 10 ⁻⁴ or less. And a step of placing an ultra-low-shrinkage concrete prepared so as to form an anionic surfactant on the surface of the placed ultra-low-shrinkage concrete.
Moreover, the concrete structure according to the present invention has cement, coarse aggregate, fine aggregate and water as main materials, and limestone is used as a raw material for the coarse aggregate and the fine aggregate, and the viscosity is high. An admixture of 10 to 200 mPa · s (20 ° C.) is blended, the binder water ratio is 1.54 to 3.33, and the drying shrinkage at 6 months of age is 1.5 × 10 ⁻⁴ or less. And a curing layer provided with an anionic surfactant on the surface of the substrate.

In the surface finishing method and concrete structure of the concrete structure thus configured, the coarse aggregate and the fine aggregate constituting the ultra-low-shrinkage concrete both use limestone and have a viscosity of 10 to 200 mPa · s ( 20 ° C.) is mixed, and the binder water ratio is 1.54 to 3.33. As a result, the drying shrinkage performance is improved without impairing the original performance of the concrete, including the separability of fresh concrete. Therefore, since the ultra-low shrinkage concrete has an excellent dry shrinkage performance of 1.5 × 10 ⁻⁴ or less, the surface shrinkage of the ultra-low shrinkage concrete can be suppressed.
Moreover, the hydrophobic group of the anionic surfactant applied as a curing agent suppresses the evaporation of moisture in the ultra-low shrinkage concrete. Therefore, cracks can be suppressed and a concrete structure with a good appearance can be obtained.

Further, the surface finishing method of the concrete structure according to the present invention is mainly composed of cement, coarse aggregate, fine aggregate and water, and limestone is used as a raw material for the coarse aggregate and the fine aggregate, Mixing the admixture material, the concrete plastic viscosity is 10-200 Pa · s, the binder water ratio is 1.54-3.33, and the drying shrinkage at 6 months of age is 1.5 × 10 ⁻⁴ or less. It is characterized by comprising a step of placing the ultra-low shrinkage concrete thus prepared and a step of applying an anionic surfactant to the surface of the placed ultra-low shrinkage concrete.
Further, the concrete structure according to the present invention has cement, coarse aggregate, fine aggregate and water as main materials, and limestone is used as a raw material for the coarse aggregate and the fine aggregate, and an admixture The concrete plastic viscosity was 10 to 200 Pa · s, the binder water ratio was 1.54 to 3.33, and the drying shrinkage at 6 months of age was 1.5 × 10 ⁻⁴ or less. It is characterized by comprising a base material formed of ultra-low shrinkage concrete and a curing layer provided with an anionic surfactant on the surface of the base material.

In the surface finishing method and concrete structure of the concrete structure configured as described above, the coarse aggregate and the fine aggregate constituting the ultra-low-shrinkage concrete are both made of limestone and mixed with an admixture. The plastic viscosity is 10 to 200 Pa · s, and the binder water ratio is 1.54 to 3.33. Therefore, since the ultra-low shrinkage concrete has an excellent dry shrinkage performance of 1.5 × 10 ⁻⁴ or less, the crack of the surface of the ultra-low shrinkage concrete can be suppressed.
Moreover, the hydrophobic group of the anionic surfactant applied as a curing agent suppresses the evaporation of moisture in the ultra-low shrinkage concrete. Therefore, cracks can be suppressed and a concrete structure with a good appearance can be obtained.

  The surface finishing method for a concrete structure according to the present invention may further include a polishing step of polishing the surface of the anionic surfactant applied to the surface of the ultra-low shrinkage concrete with a polishing machine. preferable.

  According to the surface finishing method of the concrete structure configured as described above, cracks are suppressed and the surface finish can be improved.

  In the surface finishing method for a concrete structure according to the present invention, the limestone is preferably high-purity limestone having a CaO component of 50% or more.

  In the surface finishing method of the concrete structure configured as described above, the limestone is high-purity limestone having a CaO component of 50% or more, and therefore, the drying shrinkage rate of the ultra-low-shrinkage concrete can be improved.

In the surface finishing method for a concrete structure according to the present invention, the unit amount of the admixture may be 10 to ³⁰ kg / m ³ in terms of solid content.

  In the surface finishing method of the concrete structure thus configured, the separability of the material constituting the ultra-low-shrinkage concrete can be appropriately maintained while the admixture increases the viscosity of the ultra-low-shrinkage concrete.

Moreover, in the surface finishing method for a concrete structure according to the present invention, the cement may be Portland cement, and the Portland cement may be ordinary cement, medium heat cement or low heat cement.
Moreover, in the surface finishing method for a concrete structure according to the present invention, the ultra-low shrinkage concrete may further contain an expansion material.

  In the surface finishing method for a concrete structure configured as described above, particularly moderately heated cement can suppress the cost and can sufficiently improve the drying shrinkage rate. Further, the expansion material can suppress the drying shrinkage rate of the ultra-low shrinkage concrete.

  According to the surface finishing method for a concrete structure and the concrete structure according to the present invention, cracks can be suppressed and a concrete structure having a good appearance can be obtained.

It is the table | surface which shows the (a) component material of the ultra-low-shrinkage concrete which concerns on 1st Embodiment of this invention, (b) The table | surface which shows preparation, (c) The graph which shows a drying shrinkage rate test result. It is sectional drawing of the concrete structure which concerns on 1st Embodiment of this invention. In the surface finishing method for a concrete structure according to the first embodiment of the present invention, (a) left side: photograph of the surface of ultra-low shrinkage concrete after application of an anionic surfactant, right side: an anionic surfactant It is the photograph of the surface of the ultra low shrinkage concrete after application | coating and grind | polishing, (b) (a) The enlarged photograph of the right side. (A) Table showing constituent materials of ultra-low shrinkage concrete according to Non-Patent Document 1 according to Comparative Example of the present invention, (b) Table showing formulation, (c) Drying shrinkage test for each formulation shown in (b) It is a graph which shows the result. It is the table | surface which shows the (a) component material of the ultra-low-shrinkage concrete which concerns on 2nd Embodiment of this invention, (b) The table | surface which shows preparation. (A) a graph showing the relationship between the thickener amount and viscosity of the admixture when the shrinkage reducing agent is an alkylene oxide adduct of a lower alcohol, and (b) a co-weight of the shrinkage reducing agent with low molecular weight ethylene oxide. It is a graph which shows the relationship between the amount of thickeners of an admixture, and a viscosity in the case of a coalescence (solid content: 12 kg / con · m ³ ). It is a figure which shows the test level of the plastic viscosity test of fresh concrete. (A) The figure which shows the test level (water binder ratio and unit water quantity) of a drying shrinkage rate test, (b) The figure which showed the test level (expansion material kind and quantity) of a drying shrinkage rate test, (c) Drying shrinkage It is a figure which shows the test level (a shrinkage reducing agent kind and quantity) of a rate test. It is a graph which shows the relationship between binder water ratio (B / W) and the plastic viscosity of fresh concrete. It is a graph which shows the drying shrinkage rate test result of the test body from which a water binder ratio and unit water amount differ. It is a graph which shows the drying shrinkage rate test result of the test body from which an expansion material kind and its quantity differ. It is a graph which shows the drying shrinkage rate test result of the test body from which the shrinkage reducing agent kind and its quantity differ. It is a graph which shows the drying shrinkage rate test result of the test body when not considering the case where the initial effect of the expansion material is considered.

(First embodiment)
A surface finishing method for a concrete structure according to the first embodiment of the present invention will be described.
First, the ultra-low shrinkage concrete used in this embodiment and the anionic surfactant used as a curing agent will be described.

The ultra-low shrinkage concrete according to the first embodiment is prepared with cement, coarse aggregate, fine aggregate and water as main materials, as shown in FIG. Limestone is used as a raw material for the material, and an admixture with a viscosity of 10 to 200 mPa · s (20 ° C.) is blended to obtain a binder water ratio of 1.54 to 3.33, and drying at a material age of 6 months. The shrinkage rate was prepared so as to be 1.5 × 10 ⁻⁴ or less.

  Moreover, it is preferable to employ Portland cement as the cement. This Portland cement may be ordinary cement, but it is particularly preferable to use moderately hot cement or low heat cement that can suppress heat of hydration. Of these, medium-heat cement is optimal because it provides a sufficient effect of improving the drying shrinkage at low cost.

  When the purity of the limestone as the coarse aggregate and the fine aggregate is low, the effect of improving the drying shrinkage rate may be slightly impaired, so the CaO (calcium carbonate) component is at least 50% or more, and 55 if possible. It is preferable to use high-purity limestone that is at least%.

  As the admixture, various shrinkage reducing agents, especially water retention type shrinkage reducing agents mainly composed of special polyoxyalkylene glycol are used. The admixture is not limited to a water retention type shrinkage reducing agent mainly composed of a special polyoxyalkylene glycol, and various shrinkage attenuating agents and thickening agents can be used as long as the viscosity is 10 to 200 mPa · s (20 ° C.). Arbitrary admixture materials including those can be used.

  Furthermore, it is preferable that the ultra-low shrinkage concrete contains various expansion materials, particularly lime-based, ettringite-based, or lime-ettringite-based expansion materials.

The unit amount of the admixture is preferably 10 to ³⁰ kg / m ³ in terms of solid content, and in the case of using an expanding material, the unit amount is preferably 15 to 25 kg / m ³ .

  The anionic surfactant used as a curing agent is a surfactant that penetrates into ultra-low shrinkage concrete and ionizes hydrophobic groups into negative ions in water. This hydrophobic group suppresses evaporation of moisture in the ultra-low shrinkage concrete.

  Next, the surface finishing method of the concrete structure using the ultra-low shrinkage concrete and the anionic surfactant configured as described above will be described. This embodiment demonstrates the case where this invention is applied to the slab of a building.

  First, after reinforcing bars (not shown) are arranged, a mold (not shown) is assembled. Next, as shown in FIG. 2, a step of placing the ultra-low shrinkage concrete configured as described above is executed. Thereby, the base material 1 is formed.

  Next, the process of apply | coating the anionic surfactant shown above on the surface of the base material 1 is performed, and it cures. Thereby, the curing layer 2 is formed on the surface of the substrate 1.

  And the grinding | polishing process of grind | polishing the surface of the curing layer 2 with a 100th grinder is performed, for example, and the surface finishing of a slab is completed and the concrete structure 10 is completed.

  Here, the left side of FIG. 3 (a) is a photograph of the surface of the ultra-low shrinkage concrete after the application of the anionic surfactant, and the right side of FIG. 3 (a) is the ultra-low shrinkage concrete after being further polished. FIG. 3B is an enlarged photograph on the right side of FIG. 3A. FIG. 3 shows that cracking of the concrete structure is suppressed. Moreover, it turns out that the fine aggregate and coarse aggregate contained in the base material 1 are visible.

In the surface finishing method of the concrete structure thus configured, limestone is used as both the coarse aggregate and the fine aggregate constituting the ultra-low shrinkage concrete, and the viscosity is 10 to 200 mPa · s (20 ° C.). The material is blended, and the binder water ratio is 1.54 to 3.33. As a result, the drying shrinkage performance is improved without impairing the original performance of the concrete, including the separability of fresh concrete. Therefore, since the dry shrinkage rate at the age of 6 months of the ultra-low shrinkage concrete has an excellent dry shrinkage performance of 1.5 × 10 ⁻⁴ or less, the surface crack of the ultra-low shrinkage concrete can be suppressed. Furthermore, since the breathing in which fine aggregates and coarse aggregates sink and water floats can be suppressed, the fine aggregates and coarse aggregates contained in the substrate 1 can be seen. Moreover, the hydrophobic group of the anionic surfactant applied as a curing agent suppresses the evaporation of moisture in the ultra-low shrinkage concrete. Therefore, a concrete structure having a good appearance can be obtained.

  Moreover, since the limestone is high-purity limestone having a CaO component of 50% or more, the drying shrinkage rate of the ultra-low shrinkage concrete can be improved. Moreover, the admixture can maintain moderately the separability of the material which comprises ultra-low-shrinkage concrete.

  In particular, when moderately hot cement is used as the cement, the cost can be reduced and a sufficient drying shrinkage improvement effect can be obtained. Moreover, since the initial expansion stress of the expansion material relieves shrinkage stress due to drying, cracking of ultra-low-shrinkage concrete can be suppressed.

(Examples and comparative examples)
Hereinafter, the example of the ultra-low shrinkage concrete described in the first embodiment and the comparative example of the ultra-low shrinkage concrete described in Non-Patent Document 1 will be described in comparison.

  An Example mix | blends ultra-low-shrinkage concrete as shown in FIG.1 (b) using the material shown to Fig.1 (a). On the other hand, in the comparative example, using the material shown in FIG. 4 (a), among the preparations shown in FIG. 4 (b), the sample that gave the best results in the dry shrinkage test results shown in FIG. 4 (c) No. 55-20 and no. 47-20 ultra low shrinkage concrete.

As shown in FIG. 1 (c), the conventional 200 μ class ultra-low shrinkage concrete shown in the comparative example is 2 × 10 ⁻⁴ (200 μ) even when the dry shrinkage rate at the age of 180 days (6 months) is the best. Over. On the other hand, it can be seen that the ultra-low shrinkage concrete shown in the examples has an excellent drying shrinkage performance of 100 μ class, which is slightly over 1 × 10 ⁻⁴ . That is, according to the present invention, it was confirmed that the intended purpose of realizing ultra-low shrinkage concrete having a drying shrinkage ratio of 1.5 × 10 ⁻⁴ or less can be sufficiently achieved.

(Second Embodiment)
Then, the surface finishing method of the concrete structure based on 2nd Embodiment of this invention is demonstrated.
The ultra-low shrinkage concrete used in the second embodiment is prepared using cement, coarse aggregate, fine aggregate, and water as main materials in the same manner as the ultra-low shrinkage concrete used in the first embodiment. All were prepared using limestone as a raw material for the fine aggregate so that the drying shrinkage at 6 months of age was 1.5 × 10 ⁻⁴ or less.
And in 1st Embodiment, although the admixture whose viscosity in 20 degreeC is 10-200 mPa * s is mix | blended, in 2nd Embodiment, the plastic viscosity of fresh concrete is 10-200 Pa * s. The admixture is blended, and the binder water ratio is 1.54 to 3.33.
In the second embodiment, the materials other than the admixture are the same as those in the first embodiment, and the description of the steps other than the preparation of the material other than the admixture and the ultra-low shrinkage concrete is omitted.

  In the second embodiment, when preparing ultra-low-shrinkage concrete, limestone is used as the coarse aggregate and the fine aggregate as in the first embodiment, and the plastic viscosity of the fresh concrete is 10 to 200 Pa · s. As long as the admixtures are mixed, the specific materials used and mixing are arbitrary, and the optimum mixing design is considered each time taking into account the concrete application, required performance and other conditions to be applied. However, if a specific example is given, it is preferable to use the material shown in FIG.

As shown in FIG. 5, a shrinkage reducing agent and a thickening agent are used as the admixture.
Examples of the shrinkage reducing agent include alkylene oxide adducts of lower alcohols, copolymers of low molecular weight ethylene oxide and propylene oxide, special polyoxyalkylene glycols, and the like as main components.
Examples of the thickener include powdered water-soluble cellulose ether, alkylammonium salt, alkylallylsulfonate, and the like.
The material used as the admixture may be other than the above.

Here, the thickener is used together with the shrinkage reducing agent when the desired viscosity of the fresh concrete cannot be obtained when only the shrinkage reducing agent is used as the admixture, and the plastic viscosity of the fresh concrete is adjusted to 10 to 10. Used for 200 Pa · s.
In the second embodiment, only the shrinkage reducing agent, or the shrinkage reducing agent and the thickening agent are used as admixtures, and the plastic viscosity of the fresh concrete is set to 10 to 200 Pa · s.

In the surface finishing method of the concrete structure thus configured, the coarse aggregate and the fine aggregate constituting the ultra-low-shrinkage concrete are both made of limestone and mixed with an admixture to give a concrete plastic viscosity of 10 ˜200 Pa · s, and the binder water ratio is 1.54 to 3.33. Therefore, since the ultra-low shrinkage concrete has an excellent dry shrinkage performance of 1.5 × 10 ⁻⁴ or less, the crack of the surface of the ultra-low shrinkage concrete can be suppressed.

(Relationship between amount of thickener added to shrinkage reducing agent and viscosity)
Here, regarding the admixture, the relationship between the amount of the thickener mixed in the shrinkage reducing agent and its viscosity will be described.
The viscosity of the admixture was measured using a B-type viscometer. The viscosity of the admixture is preferably 10 to 200 mPa · s (20 ° C.).
As shown in FIG. 6 (a), when the shrinkage reducing agent of the admixture is an alkylene oxide adduct of a lower alcohol, it can be seen that when the thickener is used, the viscosity increases proportionally with the amount of mixing.
In addition, as shown in FIG. 6B, when the shrinkage reducing agent of the admixture is a copolymer with low molecular weight ethylene oxide, when a thickener is used, the viscosity increases proportionally with the amount of mixing. I understand that.

As described above, when the admixture used is a lower alcohol alkylene oxide adduct or a low-molecular-weight copolymer of ethylene oxide and propylene oxide as a shrinkage reducing agent, a thickener (water-soluble) is used. In the case of using a special polyoxyalkylene glycol as a main component as a shrinkage reducing agent, it is preferable to use only a shrinkage reducing agent without mixing a thickener.
And in mix | blending concrete, the shrinkage | contraction reducing agent (solid content) mixing amount shall be 10-30 kg / m < ³ >, and the mixing amount of a thickener shall be 0-0.6 kg / m < ³ >.

  Here, when preparing the cement paste, compared with the conventional method in which a thickener is added to the cement and mixed, and then a mixture of water and a shrinkage reducing agent is added and mixed. The method of mixing and mixing the mixture of the shrinkage reducing agent and the thickening agent afterwards increases the degree of concrete kneading and prepares a homogeneous cement paste in a short time. I was able to confirm.

7 and 8 show the test level of the dry shrinkage test for the ultra-low shrinkage concrete according to the second embodiment. FIG. 7 shows the type of shrinkage reducing agent for testing the plastic viscosity of fresh concrete as level A, the water binder ratio, and the unit amounts of various materials. 8 (a) shows a dry shrinkage rate (water binder ratio and unit water amount) as level B, FIG. 8 (b) shows a dry shrinkage rate (expansion material type and amount), and FIG. Level C shows the water binder ratio for testing the drying shrinkage ratio (shrinkage reducing agent type and amount), and unit amounts of various materials.
In FIGS. 7 and 8, (1) of the expanding material is lime-based, (3) is a lime-ettringite-based expanding material, and (1) of the shrinkage reducing agent is an alkylene oxide adduct of a lower alcohol as a main component. (2) shows a main component of a copolymer of low molecular weight ethylene oxide and propylene oxide, and (3) shows a main component of a special polyoxyalkylene glycol.
Moreover, in this embodiment, drying is started on the material age 7th.

From FIG. 9, it was confirmed that the plastic viscosity of fresh concrete was 10 to 200 (Pa · s) in the range of the binder water ratio of 1.54 to 3.33 (water binder ratio of 65 to 30%). .
And from FIG. 10 thru | or 12, it has confirmed that the test body with a water binder ratio of 65-30% became 1.5 * 10 < ^-4 > or less in the drying shrinkage | contraction rate in material age 6 months.
Thereby, also in the second embodiment, it is confirmed that the intended purpose of realizing ultra-low-shrinkage concrete having a drying shrinkage rate of 1.5 × 10 ⁻⁴ or less at the age of 6 months can be sufficiently achieved. did it.

It is known that the expansion material exerts its effect before the drying period (age 0 to 7 days), so that the effect on the drying shrinkage of the concrete during the drying period (after 7 days of age) is minor. Yes.
However, since the effect of the expansion material before the drying period is −1 × 10 ⁻⁴ or more in terms of the drying shrinkage, considering the effect of the expansion material, as shown in FIG. An ultra-low shrinkage concrete having a rate corresponding to 0.5 × 10 ⁻⁴ or less can be realized.
In addition, when the plastic viscosity of fresh concrete is outside the range of 10 to 200 (Pa · s), separation occurs, so that it does not hold as concrete, and the drying shrinkage at 6 months of age is 1.5 ×. It was found to exceed 10 ⁻⁴ .

  1 (a), (b) and FIGS. 5 (a), (b) show the optimum material and the optimum blending when preparing the ultra-low shrinkage concrete according to the present invention, respectively. The present invention is not limited to this. In other words, as long as the coarse aggregate and the fine aggregate both employ limestone and use an admixture with a viscosity of 10 to 200 mPa · s (20 ° C.), the specific materials and preparations are arbitrary. . Therefore, an optimum blending design may be performed as appropriate in consideration of concrete usage, required performance, and other conditions.

  It should be noted that the assembly procedure shown in the above-described embodiment, or the shapes and combinations of the constituent members are examples, and various modifications can be made based on design requirements and the like without departing from the gist of the present invention.

  Moreover, in embodiment shown above, although the slab of the building was mentioned as an example and demonstrated as a concrete structure, this invention is not restricted to this, It can apply also to the wall etc. of a building.

DESCRIPTION OF SYMBOLS 1 ... Base material 2 ... Curing layer 10 ... Concrete structure

Claims (9)

Cement, coarse aggregate, fine aggregate, and water are used as main materials, and limestone is used as a raw material for the coarse aggregate and the fine aggregate, and an admixture having a viscosity of 10 to 200 mPa · s (20 ° C.) is used. Mixing and placing the ultra-low shrinkage concrete prepared so that the water ratio of the binder is 1.54 to 3.33 and the dry shrinkage rate at 6 months of age is 1.5 × 10 ⁻⁴ or less. Process,
And a step of applying an anionic surfactant to the surface of the cast ultra-low shrinkage concrete. Cement, coarse aggregate, fine aggregate, and water are the main materials, and limestone is used as a raw material for the coarse aggregate and the fine aggregate, and an admixture is blended to give a concrete plastic viscosity of 10 to 200 Pa · s, the ratio of the binder water ratio is 1.54 to 3.33, and the step of placing ultra-low shrinkage concrete prepared so that the drying shrinkage at 6 months of age is 1.5 × 10 ⁻⁴ or less When,
And a step of applying an anionic surfactant to the surface of the cast ultra-low shrinkage concrete.   The concrete structure according to claim 1, further comprising a polishing step of polishing the surface of the anionic surfactant applied to the surface of the ultra-low shrinkage concrete with a polishing machine. Surface finishing method.   The surface finishing method for a concrete structure according to any one of claims 1 to 3, wherein the limestone is high-purity limestone having a CaO component of 50% or more. 5. The surface finishing method for a concrete structure according to claim 1, wherein a unit amount of the admixture is 10 to ³⁰ kg / m ³ in terms of solid content. The cement is Portland cement;
The surface finishing method for a concrete structure according to any one of claims 1 to 5, wherein the Portland cement is ordinary cement, medium heat cement or low heat cement.   The surface finishing method for a concrete structure according to any one of claims 1 to 6, wherein the ultra-low shrinkage concrete is further mixed with an expansion material. Cement, coarse aggregate, fine aggregate, and water are used as main materials, and limestone is used as a raw material for the coarse aggregate and the fine aggregate, and the viscosity is 10 to 200 mPa · s (20 ° C.). A base material formed of ultra-low shrinkage concrete with blended materials, a binder water ratio of 1.54 to 3.33, and a dry shrinkage of 1.5 × 10 ⁻⁴ or less at 6 months of age When,
A concrete structure comprising a curing layer provided with an anionic surfactant on the surface of the substrate. It has cement, coarse aggregate, fine aggregate and water as main materials, and both limestone is used as a raw material for the coarse aggregate and the fine aggregate, and an admixture is blended to give a concrete plastic viscosity of 10 to 10%. 200 Pa · s, a binder water ratio of 1.54 to 3.33, and a base material formed of ultra-low shrinkage concrete having a dry shrinkage rate of 1.5 × 10 ⁻⁴ or less at a material age of 6 months; ,
A concrete structure comprising a curing layer provided with an anionic surfactant on the surface of the substrate.