JP5831132B2 - Repair method for concrete structures - Google Patents

Description

  The present invention relates to a method for repairing concrete used for concrete cross-section repair and the like.

  Concrete used for various structures is inherently excellent in durability, but part of it may deteriorate depending on the structure and use environment. Such deterioration causes a decrease in the strength of the concrete and needs to be repaired. At the time of restoration, a repair method is used in which after the deteriorated portion is removed, a restoration material such as a mortar composition is applied.

  Lightweight, high-strength cement compositions and mortar compositions that have been proposed for repairing concrete structures in the civil engineering / architectural field have been proposed. Patent Document 1 includes a cement and a glass aggregate produced by mixing a foaming agent with glass powder, granulating and firing as a mortar composition that is lightweight and has a certain level of strength and adhesive strength. A mortar composition is disclosed. In this patent document 1, the compression strength is improved by using silica fume as a part of the binder, the strength and adhesion can be improved by adding a polymer binder, and the waste glass is made of glass aggregate. It is disclosed that it can be recycled by making it a raw material.

Patent Document 2 contains a ceramic-based fired fine aggregate and silica fume, and is a lightweight mortar particularly having a specific gravity of 1.6 or less and a compressive strength of 50 N / mm ² or more as a lightweight mortar for spraying construction. Is disclosed.

  Patent Document 3 uses a lightweight aggregate for mortar in which foamed glass is coated with an organic polymer and a lightweight aggregate for mortar as a lightweight aggregate for mortar having excellent strength and alkali resistance and water permeability. A mortar composition was disclosed. In Patent Document 4, when the mortar composition is applied to the repaired part by blemish, the surface of the coating film is not conspicuous, rich in smoothness, excellent in appearance, and workability when applied with a hammer. In addition, a cement composition containing a granulated glass powder aggregate and dredged sand (natural sand) is disclosed as an excellent cement composition.

JP 2000-233961 JP 2001-039782 A JP 2003-089558 A JP 2004-256368 A

  However, in the repair method of concrete structure with mortar composition using granulated lightweight aggregate, it is possible to obtain good compressibility and good compressibility when integrated with concrete structure. However, the adhesion between the concrete structure and the cured mortar formed for repair, particularly the adhesion durability, was not sufficient.

  The present invention has good workability, and has a suitable compressive strength when integrated with a concrete structure, and can form a mortar cured body having excellent adhesion and adhesion durability. It aims at providing the repair method of a concrete structure.

  In order to achieve the above object, in the present invention, a mortar construction process for constructing a mortar composition prepared by mixing and kneading a cement composition and water at a location where a part of a concrete structure is removed, and a mortar composition A cured body forming step of curing a product and forming a mortar cured body at the location, wherein the cement composition comprises Portland cement, limestone powder, an inorganic expansive material, Fine aggregate, lightweight aggregate and re-emulsified resin powder, wherein the lightweight aggregate is obtained by firing a raw material containing glass as a main component, and the re-emulsified resin powder is a major component A method for repairing a concrete structure containing a styrene / acrylic copolymer resin and having a glass transition temperature (Tg) of −10 to 22 ° C. is provided.

  The method for repairing a concrete structure of the present invention uses a cement composition and a mortar composition containing specific components as a repair cement composition and a repair mortar composition, and thus has good workability. A mortar hardened body having an appropriate compressive strength (that is, a compressive strength equal to or higher than that of a concrete structure) when integrated with a concrete structure, and having excellent adhesion and adhesion durability can be formed. . Therefore, a concrete structure that is sufficiently excellent in durability after repair can be obtained. As described above, in the method for repairing a concrete structure of the present invention, the reason why the mortar cured body has excellent adhesion and adhesion durability is not necessarily clear. Each component contained in the product interacts with each other, and the action caused by the combination of the specific lightweight aggregate and the specific re-emulsified resin powder is considered to contribute to the improvement of adhesion and adhesion durability. ing.

  Another reason may be that the behavior at the adhesive interface with respect to fluctuations in outside air temperature is improved. That is, the mortar composition usually tends to generate fine cracks due to fluctuations in the outside air temperature (for example, when one year has passed outdoors), and the adhesiveness tends to decrease. However, according to the mortar composition of the present invention, by including the styrene / acrylic copolymer-based re-emulsified resin powder having a glass transition temperature of −10 to 22 ° C., in an environment where the temperature varies between low temperature and high temperature. It is considered that a mortar cured body having excellent adhesion and adhesion durability can be formed even when used.

  The method for repairing a concrete structure of the present invention is preferably in the following manner. Moreover, as for the repair method of the concrete structure of this invention, it is more preferable to combine the following aspects suitably.

  The lightweight aggregate of the cement composition used in the method for repairing a concrete structure of the present invention has a bulk specific gravity of 0.25 to 0.60, a particle diameter of 1200 μm or more and a mass ratio of particles less than 2500 μm. Is 45 mass% or less, and the mass ratio of particles having a particle diameter of 600 μm or more and less than 1200 μm is preferably 40 to 70 mass%. Thereby, the workability at the time of repair can be further improved.

  In the cement composition used in the method for repairing a concrete structure according to the present invention, 5 to 80 parts by mass of limestone powder, 5 to 15 parts by mass of an inorganic expansion material, and 5 of fine aggregate with respect to 100 parts by mass of Portland cement. It is preferable to contain -90 mass parts, 3.5-30 mass parts of lightweight aggregates, and 3-15 mass parts of re-emulsified resin powder. Thereby, it becomes possible to form a mortar cured body having better compressive strength and better adhesion durability, and the durability of the concrete structure after repair can be further improved.

  In the cement composition used in the method for repairing a concrete structure according to the present invention, the inorganic expansion material preferably includes a quicklime-gypsum expansion material. Thereby, it becomes possible to form a mortar cured body having better compressive strength and better adhesion durability, and the durability of the concrete structure after repair can be further improved.

  According to the present invention, it is possible to form a mortar cured body having good workability, having a suitable compressive strength when integrated with a concrete structure, and having excellent adhesion and adhesion durability. A possible method of repairing a concrete structure can be provided. The method for repairing a concrete structure of the present invention is suitably used for cross-sectional repair of a concrete structure.

It is a schematic diagram which shows an example of the concrete structure which has a degradation part to which the repair method of the concrete structure of this invention is applied. It is a schematic diagram which shows the concrete structure after removing the part containing a degradation part from the concrete structure of FIG. It is a schematic diagram which shows the concrete structure after a rust preventive agent was apply | coated to the reinforcing bar. It is a schematic diagram which shows the concrete structure in which the primer layer was formed on the inner wall surface of a recessed part. It is a schematic diagram of the concrete structure after constructing the repair mortar composition once in the recess. It is a schematic diagram of the concrete structure which the mortar composition for repair was filled in the recessed part by performing a mortar construction process, and was integrated with the mortar composition for repair. It is a schematic diagram which shows the construction method by a spraying construction method.

  A preferred embodiment of the method for repairing a concrete structure according to the present invention will be described below. The method for repairing a concrete structure according to this embodiment includes a deteriorated concrete removing step for removing a portion including a deteriorated portion of the concrete structure, and a kneaded mixture of a cement composition containing a predetermined component and water at the removed portion. Repair method (repair method) of a concrete structure having a mortar construction process for constructing the prepared mortar composition and a cured body forming process for curing the mortar composition to form a mortar cured body at the above-mentioned location It is. Hereinafter, details of each step will be described with reference to the drawings.

  FIG. 1 is a schematic view showing a partial surface and a cross section of a concrete structure 100 having a deteriorated portion to which the concrete structure repair method of the present embodiment is applied. That is, FIG. 1 (A) is a view showing the surface of the concrete structure 100 having a deteriorated portion, and FIG. 1 (B) is a line (b)-(b) of the concrete structure 100 in FIG. 1 (A). It is sectional drawing which shows a cross section typically.

  A concrete structure 100 shown in FIG. 1 includes concrete portions 11 and 12 and reinforcing bars 13 and 15 embedded in the concrete portions 11 and 12.

  The deteriorated concrete removing step is a step of removing a portion including a deteriorated portion of the concrete structure. Specifically, first, a deteriorated concrete portion 12 (deteriorated portion) is specified by an examination such as appearance observation and a sounding method. Next, an area 14 including the concrete portion 12 and a part of the healthy concrete portion 11 around the concrete portion 12 is determined so that the deteriorated concrete portion 12 is completely removed from the concrete structure 100. To do. This region 14 is a place where the concrete structure 100 is removed. By scraping the region 14, the concrete in the region 14 can be removed from the concrete structure 100.

  Specifically, first, on the surface of the concrete structure 100 as shown in FIG. 1A, an incision of about 10 mm is made in the depth direction from the concrete surface along the region 14 using an electric cutter or the like. Then, depending on the size of the area 14 to be picked up, a hammer, a hand breaker, a shot blast, a water jet or the like is appropriately selected to pick up the concrete in the area 14 [FIG. 1 (B)].

  FIG. 2 is a schematic diagram showing a surface and a cross section of the concrete structure 101 from which a portion including a deteriorated portion is removed. That is, FIG. 2 (A) is a view showing the surface of the concrete structure 101 from which a portion including a deteriorated portion is removed, and FIG. 2 (B) is a diagram (b) − of the concrete structure 101 in FIG. 2 (A). It is sectional drawing which shows typically the cross section in the (b) line.

  In the deteriorated concrete removing step, as shown in FIGS. 2A and 2B, a concrete structure 101 from which a portion including the deteriorated portion is removed is obtained. The concrete structure 101 has a concave portion formed by scraping concrete, and the concave portion is corroded with rust and has a rust attached to the surface portion and a part of the non-corroded reinforcing bar 13. And are exposed. Rust of the reinforcing bar 15 can be removed by a technique such as a wire brush or shot blasting.

  FIG. 3 is a schematic view showing a reinforcing bar to which a rust preventive material is applied and a surface and a cross section of a concrete structure 102 having the reinforcing bar. That is, FIG. 3 (A) is a view showing a reinforcing bar to which the rust preventive material 16 is applied and the surface of the concrete structure 102 having the reinforcing bar, and FIG. 3 (B) is a concrete structure 102 of FIG. 3 (A). It is sectional drawing which shows typically the cross section in the (b)-(b) line | wire.

  The rust preventive material 16 can be applied to the rebar 15 from which rust has been removed. Moreover, as shown in FIG. 3, you may apply the rust preventive material 16 also to the exposed part of the reinforcing bar 13 which is not corroded. As the rust preventive material 16, a polymer cement-based rust preventive material containing a cement composition, a synthetic resin (polymer), a rust preventive component, water and the like can be suitably used. In application, a brush, a lysing gun or the like can be appropriately selected and used. At this time, it is preferable to apply so that there is no unapplied portion on the surface of the reinforcing bar 15.

  FIG. 4 is a schematic view showing a surface and a cross section of the concrete structure 103 in which the primer layer 17 is formed on the inner wall surface of the recess. 4A is a view showing the surface of the concrete structure 103 in which the primer layer 17 is formed on the inner wall surface of the recess, and FIG. 4B is a view of the concrete structure 103 of FIG. 4A. It is sectional drawing which shows typically the cross section in the (b)-(b) line.

  The primer layer 17 can be formed by applying a water absorption adjusting agent (primer) so as to cover the inner wall surface of the concave portion formed by peeling off, and then drying the water absorption adjusting agent. As a water absorption adjusting agent, a synthetic resin emulsion diluted with water can be suitably used. In applying the water absorption adjusting agent, a brush, a lysing gun or the like can be appropriately selected and used.

  The mortar construction step is a step of filling the concave portion of the concrete structure with the repair mortar composition 18 prepared by mixing and kneading the repair cement composition and water. In this step, it is preferable that the repair mortar composition is applied in several steps after the primer layer 17 is formed.

  The repair mortar composition 18 is prepared by blending and kneading a repair cement composition and water at a predetermined ratio. Kneading is performed using a mixer or the like until uniform. As the mixer, a hand mixer or a mortar mixer can be appropriately selected and used. The repair cement composition and repair mortar composition used here will be described later.

In the surface of the concrete structure 103 (FIG. 4A), when the area of the portion (concave portion) filled with the repair mortar composition 18 (area of the region 14 in FIG. 1A) is less than 10 m ² , It is preferable to perform the construction using a plastering method. In the plastering method, a plasterer craftsman puts an appropriate amount of a repairing mortar composition on a mortar and rubs the region 14 with a metal hammer or the like and applies it in several times. In the first construction, for example, a thickness of about 5 mm is applied. In the second and subsequent constructions, the application is repeated with a thickness of 10 mm or less. The coating thickness for one day is preferably about 30 mm.

  FIG. 5 is a schematic view showing a surface and a cross section of the concrete structure 104 after the repair mortar composition is applied once to the recesses. That is, FIG. 5 (A) is a view showing the surface of the concrete structure 104 after the repair mortar composition is applied once in the recess, and FIG. 5 (B) is the concrete structure 104 of FIG. 5 (A). It is sectional drawing which shows typically the cross section in the (b)-(b) line | wire.

  In the case of construction by the plastering method, in the final construction, the surface is finished flat with scissors so that the repairing mortar composition and the concrete structure are integrated.

  FIG. 6 is a schematic view showing a surface and a cross section of a concrete structure 105 in which a concave portion is filled with a repair mortar composition and integrated with the repair mortar composition by performing a mortar construction process. That is, FIG. 6 (A) is a diagram showing the surface of the concrete structure 105 in which the concave portion is filled with the repair mortar composition and integrated with the repair mortar composition by performing the mortar construction process. (B) is sectional drawing which shows typically the cross section in the (b)-(b) line | wire of the concrete structure 105 of FIG. 6 (A).

When the area of the part (concave part) filled with the repair mortar composition 18 (area of the region 14 in FIG. 1A) is 10 to 100 m ^{2 on} the surface of the concrete structure 104, the construction is performed by the spraying method. It is preferable.

  FIG. 7 is a schematic diagram showing a construction method by a spraying method. The spraying method is a method in which the repairing mortar composition 18 is sprayed onto the concrete structure 20 to fill the recesses (not shown in FIG. 7) with the repairing mortar composition 18. As shown in FIG. 7, the apparatus used for the spraying method can include a mixer 21, a mortar pump 22 with a hopper, an air source 23, a pressure hose 24, and a spray gun 25. As an apparatus used for the spraying method, a hopper and a mortar pump may be separated.

  In the spraying method, it is preferable that the repair mortar composition is sprayed in several times on the recess formed by scraping the deteriorated part. In the first construction, as shown in FIG. 5, the repair method mortar composition is sprayed to a thickness of, for example, about 5 mm. In the second and subsequent constructions, the repair mortar composition is sprayed repeatedly so that the thickness is within 30 mm. In the final construction, the repair mortar composition is sprayed so as to have a thickness of about 15 mm. Thereafter, the surface of the repair mortar composition is finished flat with scissors so that the concrete structure and the repair mortar composition filled in the recesses are integrated. Thereby, as shown in FIG. 6, the mortar composition for repair 18 is filled in the concave portion, and the concrete structure 105 integrated with the mortar composition for repair 18 is obtained. Thereafter, when the repair mortar composition 18 is dried, a mortar cured body is obtained, and a concrete structure integrated with the mortar cured body is obtained.

  A repaired concrete structure can be obtained by the repair method described above. When the mortar cured body obtained by this method is integrated with a concrete structure, the mortar cured body has a compressive strength equal to or higher than that of the concrete structure, and also has excellent adhesiveness and excellent adhesion durability. For this reason, the concrete structure repaired by the repair method of this embodiment is excellent in durability. Therefore, it is suitable as a repair method for a deteriorated concrete structure.

  Moreover, since the repair method of this embodiment uses the specific cement composition and the mortar composition for repair, workability is also favorable. The repair cement composition and repair mortar composition used in the repair method of the present embodiment can be suitably used in a concrete structure repair method using a plastering method or a spraying method.

  Next, an example of the cement composition for repair used for the repair method of the concrete structure of this embodiment is demonstrated. In the method for repairing a concrete structure according to the present embodiment, since a repair cement composition as described below is used, it has good workability, and when integrated with the concrete structure, it is equal to or more than the concrete structure. It is possible to obtain a concrete structure having a mortar cured body that has compressive strength and has both excellent adhesiveness and excellent adhesion durability.

  The cement composition used in the method for repairing a concrete structure according to the present embodiment is a repair cement composition used for repairing concrete. The cement composition of the present embodiment is a repair cement composition including Portland cement, limestone powder, inorganic expansion material, fine aggregate, lightweight aggregate, and re-emulsified resin powder.

  The lightweight aggregate contained in the cement composition used in the method for repairing a concrete structure according to the present embodiment is a lightweight aggregate obtained by firing a raw material containing glass as a main component (glass-fired lightweight aggregate). is there. The re-emulsifying resin powder contained in the cement composition contains a styrene / acrylic copolymer resin as a main component and has a glass transition temperature of (Tg) −10 to 22 ° C. A mortar composition for repair obtained by blending such a cement composition for repair and water and kneading has good workability. Moreover, if this repair mortar composition is used, a cured mortar cured body having an appropriate compressive strength when combined with a concrete structure and having both excellent adhesiveness and excellent adhesion durability can be obtained. Can do. Hereinafter, each component contained in the cement composition of this embodiment is demonstrated in detail.

  As the Portland cement, it is preferable to use at least one selected from ordinary Portland cement, early-strength Portland cement, ultra-early strong Portland cement, moderately hot Portland cement, sulfate-resistant Portland cement, low heat Portland cement, and white Portland cement.

  As the limestone powder, a normal commercially available product can be used. Among these, it is preferable to use limestone powder (cold stone powder) with high whiteness.

  The limestone powder preferably does not contain particles having a particle size of 300 μm or more, based on the whole limestone powder, and has a particle size of 150 μm or more and a particle mass ratio of less than 300 μm of less than 20% by mass, The mass ratio of particles having a particle size of 75 μm or more and less than 150 μm is 10 to 50% by mass. By including the limestone powder having a particle size in the above-mentioned range, the cement composition can sufficiently secure the time for constructing the repair mortar composition, and can obtain good strength. it can.

  The particle diameter of the limestone powder can be measured using several sieves having different nominal dimensions as defined in JIS Z 8801: 2006. Further, in this specification, “a mass ratio of particles having a particle diameter of 150 μm or more and less than 300 μm” means that when a sieve having a sieve size of 300 μm is used, the sieve passes through a sieve having a sieve size of 300 μm, and When a sieve having a mesh size of 150 μm is used, it means a mass ratio of particles remaining on the sieve having a mesh size of 150 μm to the entire limestone powder.

The content of limestone powder in the cement composition used in the method for repairing a concrete structure according to this embodiment is 100 parts by mass of Portland cement.
Preferably it is 5 to 80 parts by mass,
More preferably, it is 10-70 parts by mass,
More preferably, it is 15-60 mass parts,
Especially preferably, it is 20-58 mass parts.

  By containing the limestone powder in the above-described preferable range, it is possible to sufficiently secure the time for constructing the repairing mortar composition and to obtain good strength.

  As the inorganic expansion material, quick lime-gypsum expansion material, gypsum expansion material, calcium sulfoaluminate expansion material and the like can be used. Among these, it is preferable to include a quicklime-gypsum-based expansion material from the viewpoint of obtaining a mortar cured body having further excellent adhesion durability.

The content of the inorganic expansion material in the cement composition used in the method for repairing a concrete structure according to this embodiment is 100 parts by mass of Portland cement.
Preferably it is 5-15 parts by mass,
More preferably, it is 6 to 13 parts by mass,
More preferably, it is 7-12 mass parts,
Most preferably, it is 8-11 mass parts.

  By adjusting the content of the inorganic expansive material to the above range, more appropriate expansibility is expressed, and excessive shrinkage of the repaired mortar cured body can be suppressed. In addition, the generation of cracks due to excessive expansion can be sufficiently suppressed.

  The fine aggregate preferably has a mass ratio of particles having a particle diameter of 600 μm or more based on the whole fine aggregate as less than 5% by mass and a water absorption rate of 1.6% or less. As such fine aggregates, those selected from sands such as quartz sand, river sand, land sand, sea sand and crushed sand can be suitably used.

  The particle diameter of the fine aggregate can be measured by using several sieves having different nominal dimensions as defined in JIS Z 8801: 2006. Moreover, in this specification, "the mass ratio of the particle | grains whose particle diameter is 600 micrometers or more" means the mass ratio with respect to the whole fine aggregate of the particle | grains on a sieve residue when a sieve with a sieve mesh of 600 micrometers is used. Say. Further, the water absorption rate of the fine aggregate is a value measured according to the method of measuring the water absorption rate (unit:%) of the aggregate defined in JIS A 1109: 2006.

  When the fine aggregate contains coarse particles having a particle diameter of 600 μm or more in an amount of 5% by mass or more, or when the fine aggregate has a water absorption rate exceeding 1.6%, the cement composition of the present embodiment is sufficient. Excellent workability tends to be impaired. There is no restriction | limiting in particular in the lower limit of the said coarse grain part, and 0 mass% may be sufficient.

In the method for repairing a concrete structure according to the present embodiment, from the viewpoint of further improving the workability, the coarse particles in the fine aggregate are:
Preferably it is 0-3 mass%,
More preferably, it is 0 to 0.5% by mass,
More preferably, it is 0-0.2 mass%,
Most preferably, it is 0.01-0.15 mass%.

There is no restriction | limiting in particular in the lower limit of a water absorption rate, and 0% may be sufficient. From the viewpoint of further improving the workability, the water absorption rate of the fine aggregate is
Preferably 0 to 1.50%,
More preferably 0 to 1.40%,
More preferably, it is 0-1.30%,
Especially preferably, it is 0.1 to 1.28%.

  The unit volume mass of the fine aggregate is preferably 1.45 to 1.70 kg / L. Thereby, the workability can be further improved. Here, the “unit volume mass” refers to the unit volume mass (unit: kg / L) of the aggregate defined in JIS A 1104-2006.

From the viewpoint of further improving workability, the unit volume mass of fine aggregate is
Preferably it is 1.45 to 1.70 kg / L,
More preferably, it is 1.50-1.60 kg / L,
More preferably, it is 1.51-1.57 kg / L,
Particularly preferred is 1.52 to 1.55 kg / L.

The content of fine aggregate in the cement composition used in the method for repairing a concrete structure according to this embodiment is 100 parts by mass of Portland cement.
Preferably it is 5-90 parts by mass,
More preferably, it is 10-70 parts by mass,
More preferably, it is 15-55 mass parts,
Especially preferably, it is 30-40 mass parts.

  By making the content of fine aggregate in the cement composition within the above range, it has better workability and has a compressive strength equal to or higher than that of the concrete structure when integrated with the concrete structure. On the other hand, it is possible to obtain a cured mortar cured body having further excellent adhesion durability.

  The lightweight aggregate is a glass aggregate obtained by a production method having a firing step of firing a raw material mainly composed of glass (for example, a glass content of 80% by mass or more). As glass contained in the raw material, waste glass such as bottles and plate glass can be used. Further, since the glass aggregate is lightweight and is a spherical substance containing glass as a main component, it has a high strength and a small amount of water absorption. Therefore, further weight reduction can be achieved while ensuring the strength of the mortar cured body.

  The lightweight aggregate (glass aggregate) manufacturing method includes, for example, a blending process in which a raw material containing waste glass as a main component is pulverized by a pulverizer such as a ball mill, and the blended raw material is granulated by a spray dryer. A spheroidizing step for obtaining a granular product by spheronization, a baking step for baking the granular material with a rotary kiln or the like, and a classification step for classifying with a vibration sieve.

The bulk specific gravity of lightweight aggregate is
Preferably it is 0.25 to 0.60,
More preferably, it is 0.30 to 0.55,
More preferably, it is 0.33-0.50,
Especially preferably, it is 0.35-0.45.

  By setting the bulk specific gravity of the lightweight aggregate within the above range, the workability can be further improved.

The lightweight aggregate does not contain particles having a particle diameter of 2500 μm or more, and the mass ratio of particles having a particle diameter of 1200 μm or more and less than 2500 μm with respect to the entire lightweight aggregate is:
Preferably it is 45 mass% or less,
More preferably, it is 1-40 mass%,
More preferably, it is 2-37 mass%.

In addition, while satisfying the above-described mass ratio, the mass ratio of the particles having a particle diameter of 600 μm or more and less than 1200 μm with respect to the entire lightweight aggregate,
Preferably it is 40-70 mass%,
More preferably, it is 45-65 mass%,
More preferably, it is 50-60 mass%.

  By setting the particle size of the lightweight aggregate within the above-mentioned mass ratio range, it is possible to obtain a cured mortar having further excellent adhesion and further excellent adhesion durability while having better workability. it can. Thereby, the durability of the concrete structure after repair can be further improved.

  The particle diameter of the lightweight aggregate can be measured by using several sieves having different nominal dimensions as defined in JIS Z 8801: 2006. Further, in this specification, “the mass ratio of particles having a particle diameter of 1200 μm or more and less than 2500 μm” means that when a sieve having a sieve mesh of 2500 μm is used, the sieve passes through a sieve having a sieve mesh of 2500 μm and has a sieve mesh of 1200 μm. When a sieve is used, it means the mass ratio of particles remaining on a sieve having a sieve mesh of 1200 μm to the entire lightweight aggregate.

The content of lightweight aggregate is 100 parts by mass of Portland cement.
Preferably 10 to 70 parts by volume,
More preferably 15 to 60 parts by volume,
More preferably, it is 20-55 volume parts,
Particularly preferred is 30 to 50 parts by volume.

Since the lightweight aggregate normally defines the blending amount on the basis of volume, the range of the content is indicated by “capacity part”, but the following content is preferable on the mass basis. That is, the lightweight aggregate content is 100 parts by mass of Portland cement.
Preferably it is 3.5 to 30 parts by mass,
More preferably, it is 5 to 25 parts by mass,
More preferably, it is 7-22 mass parts,
Especially preferably, it is 9-20 mass parts.

  By setting the content of the lightweight aggregate in the above range, it is possible to obtain a hardened mortar having excellent workability and further excellent adhesion and adhesion durability.

  As the re-emulsifying resin powder, one produced by a known production method can be used. For example, it is preferable to use a re-emulsified resin powder obtained by spraying an aqueous polymer dispersion or removing the solvent by a method such as freeze drying and drying. The re-emulsified resin powder may have an anti-blocking agent attached to the surface of the re-emulsified resin powder.

  The re-emulsifying resin powder includes a styrene / acrylic copolymer resin as a main component, and contains 50% by mass or more of styrene and at least one alkyl (meth) acrylate in total, based on the total monomer. And what contains 0.1-50 mass% of the copolymer based on an epoxide group containing ethylenically unsaturated comonomer is preferable on the basis of total monomers. More preferably, the comonomer unit of the copolymer includes a reactive epoxide group. This makes it possible to obtain a mortar cured body having further excellent adhesion durability, and the durability of the concrete structure after repair can be further improved.

The glass transition temperature (Tg) of the re-emulsified resin powder is
-10 to 22 ° C,
Preferably 0-21 ° C
More preferably 5-20 ° C
More preferably, it is 10-20 degreeC.

  When the glass transition temperature (Tg) of the re-emulsified resin powder is in the above-mentioned range, a mortar cured body having further excellent adhesion durability can be obtained. In addition, the glass transition temperature in this specification can be measured by DSC method. Specifically, first, the test piece is heated from room temperature at a rate of 3 ° C./min, and the endothermic amount is measured with a differential scanning calorimeter to obtain an endothermic curve. Next, the glass transition temperature (Tg) can be determined from the intersection of the base line of the obtained endothermic curve and the tangent at the inflection point (the point at which the upwardly convex curve changes to the downwardly convex curve).

The content of the re-emulsified resin powder is 100 parts by mass of Portland cement.
Preferably it is 3-15 parts by mass,
More preferably 4 to 12 parts by mass,
More preferably 5 to 10 parts by mass,
Especially preferably, it is 6-9 mass parts.

  By making the addition amount of the re-emulsifying resin powder within the above range, it is possible to further improve the adhesiveness and adhesion durability between the mortar cured body and the concrete structure. Thereby, the durability of the concrete structure after repair can be further improved.

  The cement composition of the present embodiment preferably includes synthetic resin fibers from the viewpoint of improving the bending strength of the mortar cured body and obtaining a mortar cured body having a good surface in which generation of cracks is sufficiently suppressed. .

  As the synthetic resin fibers, synthetic resin fibers made of synthetic resin components such as polyethylene, ethylene / vinyl acetate copolymer (EVA), polyolefin such as polypropylene, polyester, polyamide, polyvinyl alcohol, and polyvinyl chloride can be used. One kind selected from these can be used alone or in combination of two or more kinds.

The fiber length of the synthetic resin fiber is preferably 2.0 to 15 mm from the viewpoint of handling properties when mixed with the cement composition and dispersibility in the mortar composition for repair,
More preferably, it is 3.0-10 mm,
More preferably, it is 4.0-8.0 mm.
Especially preferably, it is 5.0-7.0 mm.

Synthetic resin fibers can be added as long as the properties of the cement composition are not impaired. The amount of synthetic resin fiber added is 100 parts by weight of Portland cement.
Preferably it is 0.01-5 parts by mass,
More preferably 0.05 to 2 parts by mass,
More preferably 0.08 to 1 part by mass,
Especially preferably, it is 0.3-0.5 mass part.

  By setting the fiber length and addition amount of the synthetic resin fiber within the above-described ranges, a mortar cured body having a surface in which generation of cracks is sufficiently suppressed can be obtained.

  The cement composition used in the method for repairing a concrete structure according to the present embodiment can be suitably used for cross-sectional repair of the concrete structure. By using this cement composition, it is possible to obtain a light-weight type repairing mortar composition that can be easily applied with glazing or spraying.

  The mortar composition used in the method for repairing a concrete structure according to this embodiment can be prepared by blending and kneading the above cement composition and water. An example of the mortar composition used in the present invention will be described below. This mortar composition can be suitably used as a mortar composition for repair. When preparing a mortar composition, the flow value and unit volume mass of a mortar composition can be adjusted by changing the compounding quantity of water suitably. Thus, the mortar composition for repair suitable for a use can be prepared by changing the compounding quantity of water. Here, the flow value is a value measured in accordance with a test method described in JIS R 5201-1997 “Cement physical test method”, and the unit volume mass is JIS A 1171-2000 “polymer cement”. It is a value (unit: kg / L) measured based on the test method described in “Testing method of mortar”.

The amount of water blended is 100 parts by weight of the cement composition.
Preferably 12 to 27 parts by mass,
More preferably, it is 14 to 25 parts by mass,
More preferably, it is 16-24 mass parts,
Most preferably, it is 18-23 mass parts.

The flow value of the mortar composition used in the method for repairing a concrete structure according to this embodiment is:
Preferably it is 155 to 210 mm,
More preferably, it is 160-200 mm,
More preferably, it is 165 to 190 mm,
Especially preferably, it is 170-180 mm.

  By making a flow value into the above-mentioned range, it can be set as the mortar composition which has much more favorable workability (good wiping property and spraying property).

The unit volume mass of the mortar composition used in the method for repairing a concrete structure according to this embodiment is:
Preferably it is 1.45-1.85 kg / L,
More preferably, it is 1.50-1.80 kg / L,
More preferably, it is 1.55-1.78 kg / L,
Particularly preferred is 1.50 to 1.76 kg / L (liter).

  By setting the unit volume mass within the above range, while maintaining good workability of the mortar composition (good coatability and sprayability), moderate compressive strength and further integration with the concrete structure A mortar cured body having excellent adhesiveness can be obtained.

  The mortar hardened | cured material formed with the repair method of the concrete structure of this embodiment can be obtained by hardening the above-mentioned mortar composition. An example of the obtained mortar cured body will be described below. The mortar cured body can be suitably used as a mortar cured body for repair. That is, the mortar cured body formed by curing the above mortar composition has a compressive strength equal to or higher than that of concrete when integrated with a concrete structure, and has excellent adhesiveness and excellent adhesion durability. Have both.

  Here, the compressive strength is a value measured according to a test method described in JIS R 5201-1997 “Cement physical test method”. Moreover, adhesive strength (standard time) is a value measured based on the adhesion strength test method (standard curing) as described in JIS A 6916-2000 “Preparation Coating Material for Architecture”. Adhesive strength (after wet / hot / cold test, after alkali resistance test) is standard for East Japan / Central Japan / West Japan Expressway Co., Ltd. “Structure Construction Management Guidelines July 2009 3-5-5 Performance check It is a value measured according to the adhesion test method with concrete described in “Table 3-5-2 Performance check items for cross-section repair by plastering method”.

The compressive strength of the cured mortar obtained by the method for repairing a concrete structure according to the present embodiment is as follows:
Preferably it is 30 N / mm ² or more,
More preferably, it is 32 N / mm ² or more,
More preferably, it is 34 N / mm ² or more,
Particularly preferably, it is 36 N / mm ² or more.

  When the compressive strength is in the above-described range, the cured mortar body has strength suitable for integration, that is, strength equal to or higher than that of concrete when integrated with the concrete structure.

The adhesive strength (standard time) of the mortar hardened body obtained by the method for repairing a concrete structure according to this embodiment is as follows:
Preferably it is 1.5 N / mm ² or more,
More preferably, it is 2.0 N / mm ² or more,
More preferably, it is 2.3 N / mm ² or more,
Particularly preferably, it is ^2.5 N / mm ² or more.

The adhesive strength (when wet) of the mortar hardened body obtained by the method for repairing a concrete structure according to this embodiment is as follows:
Preferably it is 1.5 N / mm ² or more,
More preferably, it is 2.0 N / mm ² or more,
More preferably, it is 2.3 N / mm ² or more,
Particularly preferably, it is ^2.5 N / mm ² or more.

  When the adhesive strength (standard time, when wet) is equal to or higher than the above value, the repaired mortar cured body has sufficiently excellent adhesiveness when integrated with the concrete structure.

The adhesive strength (after the hot and cold repeated test) of the mortar hardened body obtained by the concrete structure repair method of the present embodiment is
Preferably it is 1.5 N / mm ² or more,
More preferably, it is 1.7 N / mm ² or more,
More preferably, it is 1.9 N / mm ² or more,
Particularly preferably, it is 2.0 N / mm ² or more.

The adhesive strength (after the alkali resistance test) of the cured mortar obtained by the method for repairing a concrete structure according to this embodiment is as follows:
Preferably at 1.5 N / mm ² or more,
More preferably, it is 1.7 N / mm ² or more,
More preferably, it is 1.9 N / mm ² or more,
Particularly preferably, it is 2.0 N / mm ² or more.

  When the adhesive strength (after the hot and cold repeated test and after the alkali resistance test) is equal to or higher than the above value, the mortar cured body is excellent in adhesion durability after being integrated with the concrete structure.

  The mortar hardened body obtained by the method for repairing a concrete structure according to this embodiment can be evaluated for durability by an accelerated neutralization test. The accelerated neutralization test of the mortar cured body can measure the neutralization depth in accordance with the test method described in JIS A 1153-2003 “Accelerated neutralization test of concrete”.

The neutralization depth (average value) of the cured mortar obtained by the method for repairing a concrete structure according to this embodiment is as follows:
In the case of the age of 28 days, it is preferably 1.0 mm or less,
In the case of 56 days of age, it is preferably 1.0 mm or less,
In the case of the age of 91 days, it is preferably 2.0 mm or less,
In the case of an age of 182 days, it is preferably 3.0 mm or less.

  The mortar hardened body obtained by the method for repairing a concrete structure according to the present embodiment can be evaluated for frost damage resistance by a freeze-thaw test. The freeze-thaw test of the mortar hardened body is based on the test method described in JIS A 1148-2010 “Method of freeze-thawing concrete (Method A)”, and the primary resonance frequency and mass of the flexural vibration are measured, and the relative motion is measured. Elastic modulus and mass reduction rate can be calculated.

The relative dynamic elastic modulus of the cured mortar obtained by the method for repairing a concrete structure according to this embodiment is
In the case of about 60 cycles, it is preferably 96% or more,
In the case of about 150 cycles, it is preferably 95% or more,
In the case of about 210 cycles, it is preferably 93% or more,
In the case of about 300 cycles, it is preferably 90% or more.

The mass reduction rate of the mortar hardened body obtained by the concrete structure repairing method of this embodiment is
In the case of about 60 cycles, it is preferably 0.1% or less,
In the case of about 150 cycles, it is preferably 0.2% or less,
In the case of about 210 cycles, it is preferably 0.3% or less,
In the case of about 300 cycles, it is preferably 0.5% or less.

  The preferred embodiment of the present invention has been described above, but the present invention is not limited to the above embodiment. For example, in this embodiment, since the deteriorated portion of the concrete structure was a rectangular parallelepiped shape, repair was performed by removing the deteriorated portion into a rectangular parallelepiped shape, but the shape of the portion to be removed according to the size and shape of the deteriorated portion May be different.

  Hereinafter, the contents of the present invention will be described in more detail with reference to examples and comparative examples, but the present invention is not limited to the following examples.

(Examples 1-5, Comparative Examples 1-9)
[Preparation of cement composition for repair]
The raw materials shown in (1) to (7) below were prepared.
(1) Portland cement Normal Portland cement (manufactured by Ube Mitsubishi Cement Co., Ltd., Blaine specific surface area = 3300 cm ² / g)
(2) Limestone powder Cryosite powder (mass ratio of particles having a particle diameter of 150 μm or more and less than 300 μm = 15.2 mass%, mass ratio of particles having a particle diameter of 75 μm or more and less than 150 μm = 35.6% by mass)
(3) Inorganic expansive material ・ Quicklime-gypsum expansive material (manufactured by Taiheiyo Material Co., Ltd.)
(4) Fine aggregate ・ Silica sand (mass ratio of particles having a particle diameter of 600 μm or more = 0.1 mass%, water absorption rate = 1.25%, unit volume mass = 1.53 kg / L)

(5) Lightweight aggregate-Lightweight aggregate A: Glass aggregate obtained by firing a raw material containing glass as a main component (bulk specific gravity = 0.35, particles having a particle diameter of 1200 μm or more and less than 2000 μm) Mass ratio = 36.7 mass%, particle diameter of 600 μm or more and mass ratio of particles less than 1200 μm = 54.4 mass%)
Lightweight aggregate B: Glass aggregate obtained by firing a raw material containing glass as a main component (bulk specific gravity = 0.40, mass ratio of particles having a particle diameter of 1200 μm or more and less than 2000 μm = 36. 7 mass%, the mass ratio of particles having a particle diameter of 600 μm or more and less than ˜1200 μm = 60.2 mass%)
Lightweight aggregate C: pearlite (bulk specific gravity = 0.19, particle diameter of 1200 μm or more and less than 2000 μm, mass ratio of particles = 79.9% by mass, particle diameter of 600 μm or more and less than 1200 μm) Particle mass ratio = 10.5 mass%)

(6) Re-emulsified resin powder-Resin powder A: Styrene / acrylic copolymer re-emulsified resin powder (glass transition temperature = 15 ° C)
Resin powder B: Styrene / acrylic copolymer re-emulsified resin powder (glass transition temperature = −15 ° C.)
Resin powder C: Styrene / acrylic copolymer re-emulsified resin powder (glass transition temperature = 23 ° C.)
Resin powder D: Acrylic re-emulsified resin powder (glass transition temperature = -3 ° C.)
Resin powder E: Vinyl acetate / veova / acrylic copolymer re-emulsified resin powder (glass transition temperature = 15 ° C.)
(7) Synthetic resin fiber-Vinylon fiber (manufactured by Kuraray Co., Ltd., fiber length = 6 mm)

  (1) Portland cement, (2) Limestone powder, (3) Inorganic expansive material, (4) Fine aggregate, (5) Lightweight aggregate, (6) Re-emulsified resin powder, (7) Synthetic resin Fibers were blended at the ratios shown in Tables 1 and 2, and repair cement compositions for each Example and each Comparative Example were prepared. In Tables 1 and 2, the mixing ratio of (2) limestone powder, (3) inorganic expansion material, (4) fine aggregate, (6) re-emulsified resin powder is (1) mass relative to 100 parts by mass of Portland cement. (5) The blending ratio of the lightweight aggregate is shown in (1) capacity part with respect to 100 parts by mass of Portland cement. In addition, if the blending ratio (capacity part) of the lightweight aggregate shown in Tables 1 and 2 is multiplied by the bulk specific gravity of each lightweight aggregate, the blending ratio of the lightweight aggregate to 100 parts by mass of Portland cement (mass part) ) Can be calculated. Blanks in Tables 1 and 2 indicate unmixed.

[Preparation of mortar composition for repair]
For each 1 kg of the cement composition for repair prepared at the blending ratio shown in Table 1 and Table 2, the amounts of water shown in Table 3 and Table 4 are blended and kneaded, and the mortar composition for repair in each example and each comparative example A product was prepared. The kneading was performed at a low speed for 3 minutes using a Hobart mixer under the conditions of a temperature of 20 ° C. and a relative humidity of 65%.

[Evaluation of Repair Mortar Composition and Hardened Mortar]
The concrete structure was repaired using the repaired mortar compositions of the examples and the comparative examples. The flow value, unit volume mass, and compressive strength of the mortar composition for repair and the cured mortar were measured. Moreover, after repairing the concrete structure, the adhesive strength was measured. The measurement results were as shown in Table 3 and Table 4. Each measurement was performed by the method shown below.

(1) Measurement method of flow value The flow value was measured based on the test method described in JIS R 5201-1997 "Cement physical test method".
(2) Measuring method of unit volume mass Unit volume mass was measured based on the test method as described in JIS A1171-2000 "Test method of polymer cement mortar".
(3) Measuring method of compressive strength Based on the test method described in JIS R 5201-1997 "Physical test method of cement", compressive strength at the age of 28 days was measured.
(4) Measuring method of adhesive strength The adhesive strength was measured under different conditions as follows.
Standard time Adhesive strength at standard time was measured in accordance with the adhesion strength test method (standard curing) described in JIS A 6916-2000 “Preparation Coating Material for Building Construction”.
・ After wet, hot and cold repeated test, after alkali resistance test East Japan / Central Japan / West Japan Expressway Co., Ltd. Standard “Structure Construction Management Guidelines July 2009 Version 3-5-5 Cross Section Restoration Performance Check Table 3- In accordance with the adhesion test method with concrete described in “5-2 Performance Check Items for Cross-Section Restoration by Plastering Method”, the adhesive strength after wet, after the hot and cold repeated test and after the alkali resistance test was measured.

  The adhesive strength at the standard time and when wet was used as an index for evaluating the adhesiveness, and the adhesive strength after the repeated heating and cooling test and after the alkali resistance test was used as an index for evaluating the adhesive durability.

  As shown in Table 3 and Table 4, the mortar hardened bodies formed by the repair methods of Examples 1 to 5 had high adhesive strength in any environment. The flow values of the mortar compositions for repair in Examples 1 to 5 were 170 to 180 mm. This result shows that the repair cement composition and repair mortar composition used in each example have good workability (good coatability and sprayability).

  The unit volume mass of the mortar composition for repair used in Examples 1 to 5 was 1.50 to 1.80 kg / L. This result has shown that the cement composition for repair of each Example has favorable workability | operativity (good wiping property and spraying property).

Although the mortar hardened | cured material formed with the repair method of the comparative examples 6, 8, and 9 using the lightweight aggregate C (pearlite) uses the resin powder which each has a different glass transition temperature (Tg), Also had low adhesive strength. In particular, it was confirmed that the adhesive strength after the hot and cold repeated test and the alkali resistance test as an index of adhesion durability was 0 N / mm ² , which was inferior in durability. In Comparative Example 8, the compressive strength was 30 N / mm ² or more, but since the adhesive strength was low, no correlation was found between the compressive strength value and the adhesive strength value.

From a comparison between Comparative Example 6 in which the resin powder B was blended and Comparative Examples 5 and 7 in which the resin powder B was blended and replaced with the lightweight aggregate C (perlite) to the lightweight aggregate A (glass-fired lightweight aggregate), When lightweight aggregate A was mix | blended, the tendency for adhesive strength to become high was confirmed. However, in Comparative Examples 5 and 7, some of the four types of adhesive strength were as low as 1.5 N / mm ² or less.

From a comparison between Comparative Example 1 in which the resin powder B was blended and Example 1 in which the resin powder A was blended, it was confirmed that the adhesive strength was increased by blending the resin powder A. In Example 1, all four types of adhesive strength is at 1.5 N / mm ² or more, compressive strength was 30 N / mm ² or more.

  From the comparison between Example 1 in which the resin powder A was blended and Comparative Examples 2 and 3 in which the resin powder D was blended, when the resin powder D was blended, regardless of the blending amount of the lightweight aggregate A, after the hot and cold repeated test It was confirmed that the adhesive strength of the sheet was lowered.

From the comparison between Examples 2 and 3 in which resin powder A was blended and Comparative Example 4 in which resin powder D was blended, four types of adhesive strength were obtained regardless of the blending amount of lightweight aggregate A by blending resin powder A. Was confirmed to be 1.5 N / mm ² or more.

In Example 4 and Example 5, lightweight aggregates A and B having different bulk specific gravities are blended, and both have four types of adhesive strengths of 1.5 N / mm ² or more, and a compressive strength of 30 N / mm ² or more.

  From the above, as in Examples 1 to 5, re-emulsified resin powder (resin powder A) having a glass transition temperature in the range of −10 to 22 ° C. and made of a styrene / acrylic copolymer resin and glass firing If repair cement composition containing lightweight aggregates (lightweight aggregates A and B) is used, it has good workability and has an appropriate compressive strength when integrated with a concrete structure, and excellent adhesion It was confirmed that a mortar cured body having excellent properties and excellent adhesion durability was formed. That is, the repair cement composition of this example can be suitably used for cross-sectional repair of a concrete structure, and can easily perform operations such as glazing or spraying.

(Neutralization depth)
Using the repair mortar composition used in the repair method of Example 5 as the repair method of Example 6, a 1: 3 mortar prepared with the composition described in JIS A 5201-2002 “Physical Test Method for Cement” is a comparative example. 10 was used as a repair method, and the neutralization depth was measured in accordance with the test method described in JIS A 1153-2003 “Accelerated neutralization test of concrete”. Three specimens having a square cross-sectional shape with a side length of 100 mm and a length of 400 mm were prepared for use in the accelerated neutralization test.

  The specimen was demolded after one day of material age, cured in water until the age of 4 weeks, and then cured in air until the age of 8 weeks. Moreover, between 7 to 8 weeks of age, the driving surface, bottom surface, and both end surfaces of the specimen were sealed. Neutralization promotion conditions were 20 ° C., relative humidity 65%, and carbon dioxide concentration 5%. About the test piece in each age period, it cut | disconnected in the position of 60 mm from the edge part, sprayed the phenolphthalein 1% alcohol solution, and about the length (mm) of the part which does not turn red, it divided into 6 equally per side 5 The place was measured and the average value of the obtained values was calculated. Table 5 shows the measurement results (average values) of Example 6 and Comparative Example 10.

  As shown in Table 5, for the mortar hardened body obtained by the repair method of Example 6, the average value of the neutralization depth is 0.0 mm until the material age of 91 days, and the average value is even at the material age of 182 days. 2.0 mm, indicating excellent durability. On the other hand, the cured mortar obtained by the repair method of Comparative Example 10 had an average value of 2.4 mm at a material age of 28 days, indicating that it was not excellent in durability.

(Freeze-thaw)
Using the mortar composition for repair used in the repair method of Example 5 as the repair method of Example 7, a 1: 3 mortar prepared with the composition described in JIS A 5201-2002 “Physical Test Method for Cement” is a comparative example. 11 is used as a repair method, and in accordance with the test method described in JIS A 1148-2010 “Concrete freeze-thaw test method (Method A)”, the primary resonance frequency and mass of flexural vibration are measured, and the relative kinematic modulus is measured. The mass reduction rate was calculated. Three specimens having a square cross-sectional shape with a side length of 100 mm and a length of 400 mm were prepared for the freeze-thaw test.

  The specimens were demolded after 1 day of age, and were cured in water at 20 ° C. until the age of 4 weeks. The test starting material age is 28 days, and in one cycle of freezing and thawing, the center temperature of the specimen decreases from 5 ° C. to −18 ° C. and increases from −18 ° C. to 5 ° C., and 3 to 4 hours. did. Measurement of the primary resonance frequency and mass of the flexural vibration was performed about every 30 cycles, and the average value of the obtained values was calculated. Table 6 shows the measurement results (average values) of Example 7 and Comparative Example 11.

  As shown in Table 6, for the mortar cured body obtained by the repair method of Example 7, there is less variation in the relative kinematic modulus and mass reduction rate than the mortar cured body obtained by the repair method of Comparative Example 11, It showed excellent frost damage resistance.

  According to the present invention, it is possible to form a mortar cured body having good workability, having a suitable compressive strength when integrated with a concrete structure, and having excellent adhesion and adhesion durability. A possible method of repairing a concrete structure can be provided. The method for repairing a concrete structure of the present invention is suitably used for cross-sectional repair of a concrete structure.

  DESCRIPTION OF SYMBOLS 11, 12 ... Concrete part, 13, 15 ... Rebar, 14 ... Area | region, 16 ... Rust prevention material, 17 ... Primer layer, 18 ... Mortar composition, 20 ... Concrete structure, 21 ... Mixer, 22 ... Mortar pump, 23 ... Air source, 24 ... Pressure hose, 25 ... Spray gun, 100, 101, 102, 103, 104, 105 ... Concrete structure.

Claims (4)

A mortar construction process for constructing a mortar composition prepared by mixing and kneading a cement composition and water at a place where a part of the concrete structure is removed,
Curing the mortar composition and forming a mortar cured body at the location, and a method for repairing the concrete structure,
The cement composition includes Portland cement, limestone powder, inorganic expansion material, fine aggregate, lightweight aggregate and re-emulsified resin powder,
For 100 parts by mass of Portland cement,
5 to 80 parts by mass of the limestone powder, 5 to 15 parts by mass of the inorganic expansion material, 5 to 90 parts by mass of the fine aggregate, 3.5 to 30 parts by mass of the lightweight aggregate, and the re-emulsification. 3 to 15 parts by mass of a resin powder,
The lightweight aggregate is obtained by firing a raw material containing waste glass as a main component,
The re-emulsifying resin powder is a method for repairing a concrete structure containing a styrene / acrylic copolymer resin as a main component and having a glass transition temperature (Tg) of 5 to 20 ° C. The lightweight aggregate is
The bulk specific gravity is 0.25 to 0.60,
The mass ratio of particles having a particle diameter of 1200 μm or more and less than 2000 μm is 45% by mass or less,
The method for repairing a concrete structure according to claim 1, wherein a mass ratio of particles having a particle diameter of 600 μm or more and less than 1200 μm is 40 to 70 mass%. The limestone powder is
The mass ratio of particles having a particle size of 150 μm or more and less than 300 μm is less than 20% by mass,
The repair method of the concrete structure of Claim 1 or 2 whose mass ratio of the particle | grains whose particle diameter is 75 micrometers or more and less than 150 micrometers is 10-50 mass%.   The method for repairing a concrete structure according to any one of claims 1 to 3, wherein the inorganic expansion material includes quicklime-gypsum expansion material.