JP5918094B2 - Repair method using curable cementitious composite material - Google Patents

Description

The present invention, site can mix kneaded easily with the hand mixer and the like, to a repairing method using the hardening cement-based composite materials that to realize properties with viscosity suitable for plastering the finish.

The following patent document has been proposed as a material capable of fully exhibiting the characteristics of the original strain-hardening cementitious composite material with excellent self-filling properties and high toughness. PVA fiber (Polyvinyl Alcohol fiber, commonly known as This is related to the improvement of the workability of hardened fiber-reinforced cement composite material (FRC material), which is blended with curable cementitious composite material (called vinylon fiber). A crack-dispersed fiber reinforced cement composite material with a tensile strain of 1% or more, and blended in the following [M1] formulation matrix with the following [F1] PVA short fibers in an amount of more than 1 to 3 vol.%. It is a low shrinkage strain-hardening cementitious composite material having self-filling properties. (Referred to as ECC cleats)
[M1]
Using ordinary Portland cement or low heat Portland cement, water binder weight ratio: 25% or more,
Unit water volume: 250-400 Kg / m ³ ,
Fine aggregate binder weight ratio (S / C): 1.5 or less (including 0),
Fine aggregate maximum particle size: 0.8 mm or less, fine aggregate average particle size: 0.4 mm or less,
Intumescent material: less than 100 Kg / m ³
Welan gum: 0.05-1.0 Kg / m ³
[F1]
Fiber diameter: 50 μm or less,
Fiber length: 5-25mm,
Fiber tensile strength: 1500-2400 MPa
JP 2003-192421 A

  The ECC cleat (low-shrinkage strain-hardening cement composite material having self-filling properties) has excellent drying shrinkage at least to the same degree as that of ordinary concrete, and thus has few problems of cracking due to shrinkage. Because it has fatigue strength, it can significantly increase fatigue life, and even if it receives excessive bending moment or shear force, cracks can be suppressed to a fine level (usually about 0.1 mm), so that moisture and chemicals can penetrate. It can be suppressed, the durability of the member can be improved, and even if it undergoes a large deformation due to bending shear force during earthquake loading, the cover part of the material due to bending compression does not peel off, so a sudden decrease in the proof stress appears Absent.

In addition, the following patent document solves the problems existing in mortar materials by the conventional wet spraying method, has a high fluidity so as to be adequately adapted to wet spraying, and has an appropriate viscosity that does not cause material separation or clogging by pumping. A crack-dispersed short fiber reinforced cement composite material having a tensile strain of 1% or more in a tensile test of a cured product on the 28th day of the age, which is proposed as a material having a property having PVA short fibers satisfying the requirements, the weight ratio of water binder to 25% or more, the weight ratio of fine aggregate to binder (S / C) is 1.5 or less, the maximum particle size of fine aggregate is 0.8 mm or less, average Particle size 0.4 mm or less, unit water volume 250 kg / m ^{3 to} 450 kg / m ³ or less, air volume 3.5% to 20% or less when kneaded, high performance AE water reducing agent amount 30 kg / m ^{3 or} less Formulary matrix that satisfies the conditions 1 exceeding 3 vol. % Blended in a blending amount. (Referred to as ECC shot)
JP 2002-193653 A

  By the way, in general, in order to enable a plastering finish with a mortar repair material, an appropriate viscosity is imparted by mixing an admixture, but generally there is a limit to adding an admixture. In general, the mortar used for the plastering method has a working life with sufficient work. For this reason, it takes time to cure, and even if a thickener, resin, or the like is added to increase the adhesive strength, the thicker the construction mortar layer, the easier the deformation, dripping, peeling, and the like occur.

  Although there is a possibility that the plasterability of mortar can be greatly improved by the use of admixtures / agents, if the amount of use is increased in order to improve the workability, it is necessary for manufacturing workability other than workability and mortar for construction. There is a possibility that it may hinder the expression of properties, and there is a limit to the improvement of workability with admixtures and agents.

In view of such circumstances, the following patent document relates to an improvement considering a plastering finish of a mortar repair material.
JP 2007-238358 A JP 2006-160589 A JP 2006-182629 A JP 2007-176740 A JP 2007-320783 A JP 2009-96657 A JP 2009-120438 A

  Patent Document 3 is characterized in that the aggregate is characterized as providing an ultralight foam mortar composition having sufficient strength and suitable for plastering work, and an ultralight foam mortar using the composition. An aggregate, a foaming agent that generates bubbles in a cement paste containing the cement, a high-performance AE water reducing agent or a high-performance water reducing agent that disperses the cement particles in the cement paste to increase fluidity, An ultralight foam mortar composition comprising a thickener for increasing the viscosity of the cement paste, wherein the aggregate is spherical and has an average particle size of 0.2 to 3 mm and a bulk volume of 1 kg of the cement. The organic foamed particles are adjusted to a ratio of 1.6 to 4 liters, and the organic foamed particles are more than half of the volume ratio in the aggregate in the mortar.

  Patent Document 4 describes a plastering mortar admixture that is mixed with mortar to improve troweling workability, in particular, elongation of iron, separation of iron, sag, and finishing appearance, and a mortar composition containing the same. A clay containing one or more clay minerals selected from the group consisting of kaolinite, halloysite, pyrophyllite, talc, chlorite, montmorillonite, muskite, vermiculite. , An admixture for plastering mortar containing 0.3 to 10 parts by weight of clay having an average particle size of 0.3 to 30 μm and 100 parts by weight of a water-soluble polymer thickener; , One or more inorganic substances selected from the group consisting of fly ash, blast furnace slag powder, shirasu balloon, pearlite Serial is a plastering mortar admixture by blending in a range not exceeding 300 parts by weight per admixture 100 parts by weight for plastering mortar.

  Patent Document 5 discloses a fireproof coating mortar that can be pumped and does not sag or peel off even when sprayed on a vertical surface. , Refractory coating mortar containing aggregate, cement, water and quick setting agent, specifically, the content of calcium formate is 0.01 to 0.2 parts by weight (outer), The addition amount of the quick setting agent is 3 to 15 parts by weight (outer), and the refractory coating mortar uses a fiber having a melting point of 250 ° C. or less as the organic fiber.

  The above-mentioned patent document 6 is a thick mortar that can significantly reduce the difference in strength from a mortar using only ordinary aggregate as an aggregate. It is a thickened mortar containing fine aggregate made of materials, Portland cement, alkaline earth metal sulfate, expansion material, thickener and dispersant.

  Patent Document 7 is a cement-based mortar that has good workability at the time of manufacture and has practically necessary characteristics as a mortar for construction after construction, and dramatically improves the plastering workability for buildings. As an architectural mortar, 100 parts by volume of a porous composite of ethylene vinyl acetate copolymer and calcium carbonate, 55 to 130 parts by volume of polymer resin particles having a bulk specific gravity of 0.05 or less, and a bulk specific gravity of 0.27 It contains fine aggregate composed of 155 to 260 parts by volume of the following inorganic particles.

  Patent Document 8 is a cement-based lightweight mortar suitable for plastering such as plastering, in which the reduction of the mortar volume during production hardly occurs, and the lightweight mortar is less likely to crack due to shrinkage. For providing a plastering cement mortar with high strength development, 100 parts by weight of inorganic lightweight aggregate (A) having a particle size of 2.1 mm or less and organic lightweight aggregate (B) 42 to 234 having a particle size of 2 mm or more. A volume part, and (C) a polymer dispersion or a re-emulsifying powder resin, (D) a water retention agent and (E) a glass fiber, and a unit volume mass of 1.1 to 1.4 kg / A plastering mortar for L.

  The above-mentioned Patent Document 9 provides a building mortar having dramatically improved plastering workability to a building, 100 parts by volume of a porous composite of ethylene vinyl acetate copolymer and calcium carbonate, and a bulk specific gravity of 0. This is a building cement mortar containing fine aggregate composed of 55 to 130 parts by volume of polymer resin particles of 05 or less and 155 to 260 parts by volume of inorganic particles having a bulk specific gravity of 0.27 or less.

The materials “ECC cleat” and “ECC shot” in Patent Document 1 and Patent Document 2 have the following problems.
[ECC cleat]
・ Cannot perform plastering on vertical walls (sagging).
・ In the case of construction by formwork, early demolding is not possible.
・ Large equipment (mixer) is required for construction on site.
[ECC shot]
・ Large-scale equipment (mixer, set of spray equipment) is required for construction on site.

  The above Patent Documents 3 to 9 have been devised, but the materials "ECC Cleat" and "ECC Shot" in Patent Document 1 and Patent Document 2 have properties suitable for plastering finish. No point can be found regarding the technology to improve mortar repair materials.

The object of the present invention is to solve the disadvantages of the conventional example, taking advantage of the characteristics of a low shrinkage strain-hardening cement composite material having high durability and low self-filling ability that can be easily repaired in a small number of construction days. Furthermore, it has been difficult in the past because it can be easily kneaded using a hand mixer in the field, and can have a viscosity suitable for plastering, such as good adhesion (no sag). Another object of the present invention is to provide a repairing method using a curable cementitious composite material which can be constructed according to the conditions of the repairing surface.

In order to achieve the above object, the present invention according to claim 1 is a repair method using a curable cementitious composite material in which a curable cementitious composite material is applied to a repair surface. ] PVA short fibers satisfying the conditions of [M1] are blended in a preparation matrix satisfying the conditions of [M1] below, and the viscosity is increased so as to achieve a viscosity capable of plastering according to the properties of the repair surface and the gradient conditions. the addition amount of the agent and the high AE water reducing agent adjusted in accordance with the following matrix table, compressive strength at the age of 28 days is 30 N / mm ² or more, a tensile yield strength of 2.0 N / mm ² or more, a tensile ultimate strain 0 The gist is to set it to 2% or more.
[M1]
Using ordinary Portland cement or low heat Portland cement, water binder weight ratio: 25% or more, unit water volume: 250-400 Kg / m ³ , fine aggregate binder weight ratio (S / C): 1.5 or less (including 0) ), Maximum particle size of fine aggregate: 0.8 mm or less, average particle size of fine aggregate: 0.4 mm or less, expanded material: less than 100 Kg / m ³ [F1]
Fiber diameter: 50 μm or less, fiber length: 5 to 25 mm, fiber tensile strength: 1500 to 2400 MPa, fiber amount: more than 1 to 3 vol.%

  According to the present invention described in claim 1, the clearance between the repair object and the repaired material is reduced by filling the cracked material into the microcracks specific to the rapid-hardening high-toughness FRC material (ECC), and compared with mere mortar coating. The life cycle of fast-hardening, high-toughness FRC material (ECC), which can achieve extremely high water barrier properties, has a self-filling property of about 40 years, compared to the life cycle of resin and other coatings of 5-10 years. The characteristics of the low-shrinkage strain-hardening type cementitious composite material can be utilized.

  In addition, in the development of plastering ECC according to repair conditions, which was difficult in the past, by adjusting the blending amount of thickener and high-performance AE water reducing agent, it is not necessary to re-adjust the blending of materials, Moreover, it has become possible to achieve both the performance for plastering and the excellent performance as a repair material peculiar to ECC.

  Furthermore, since the required amount of thickener and high-performance AE water reducing agent is combined and kneaded in accordance with the angle of the repair surface, it is easy to adjust and install the plastering ECC on site.

  By applying a rapid hardening high-toughness FRC material (ECC) with a trowel (left plastering), it is possible to set the demolding frame time to about 5 hours and the repair time to within 8 hours. No sagging occurs during the application of the repair material (rapidly hard tough FRC material (ECC)).

  Furthermore, since the amount of the admixture can be adjusted according to the condition of the repair surface, the material cost of the plastering ECC can be reduced.

The present invention of claim 3 according to claim 6, wherein, if prior Symbol repaired surface of the material is made of steel, as a pretreatment, the external unit and the base to form a roughness in order to ensure a predetermined adhesion strength Combining the resin composition as a material, and the external means for forming the roughness is by means of keren, or if the material of the repair surface is made of concrete, the resin composition as a base material, Alternatively, as a resin composition, there is no decrease in strength in a 2 million times fatigue test under water-filled conditions, a compressive strength of 50 MPa or more, a compressive elastic modulus of 1000 MPa or more, a bending strength of 35 MPa or more, and a tensile shear strength of 10 MPa or more. residual tensile strength at exposure conditions E to destroy 90% or preform, intended to summarized as the use of high durability type epoxy resin adhesive That.

According to the present invention of claims 3 to 6, wherein, in addition to the operation of the present invention of the claims 3 to 6, wherein the coating of the repaired surface is made reliable by the adhesive is a resin composition A predetermined adhesion strength can be secured between the rapid-hardening high-toughness FRC material (ECC) and the repaired body through the adhesive.

  In particular, by selecting a predetermined pretreatment (specific resin composition, KS bond) according to the material of the repair surface, the predetermined performance was maintained not only on the concrete structure but also on the surface of the steel structure. ECC plasterers are possible.

Repairing method using a hardening cement-based composite materials of the present invention as described above has high durability with less construction days, taking advantage of the characteristics of the cured cement-based composite materials that can be repaired easily, further Can be easily kneaded on-site with a hand mixer, and has a viscosity suitable for plastering finish, such as good adhesion (no sag, etc.) for plastering on the vertical wall The construction according to the conditions of the repair surface, which has been difficult in the past, is possible.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. First, the curable cementitious composite material used in the present invention will be described.

A crack-dispersed short fiber reinforced cement composite material with a tensile strain of 1% or more in a tensile test of a cured product at age 28, with a compressive strength of 30 N / mm ² or more and a tensile yield strength of 2.0 N / mm ² As described above, the ultimate tensile strain is 0.2% or more, and the adhesion strength with the repair surface is 2.0 N / mm ² or more.

The reinforcing short fibers are PVA (polyvinyl alcohol) short fibers that satisfy the following condition [F1], and are blended in a blending matrix that satisfies the following condition [M1] in an amount of more than 1 and 3 vol.%. .
Formulation matrix conditions [M1]
・ Water binder weight ratio (W / C) is 25% or more ・ Non-weight (S / C) of fine aggregate and binder is 1.5 or less (including 0)
・ Maximum particle size of fine aggregate 0.8mm or less, average particle size 0.4mm or less ・ Unit water volume is 250kg / m ³ or more and 450kg / m ³ or less ・ Air volume when kneaded is 3.5% or more and 20% or less・ Expandable material: less than 100 kg / m ³

Conditions as PVA (poly vinyl alcohol) short fiber [F1]
-Fiber diameter is 0.05mm or less-Fiber length is 5-20mm
-Fiber tensile strength of 1500 MPa to 2400 MPa

  As the expansion material, a commercially available calcium sulfoaluminum-based expansion material (trade name Denka CSA # 20 manufactured by Denki Kagaku Kogyo Co., Ltd.) can be used. Instead of this, a quicklime type or a lime-ettringite composite type can also be used.

  In the formulation of [M1], if the water binder ratio of the matrix is less than 25%, the elastic modulus and fracture toughness of the matrix are high for the fiber of [F1] and multi-cracks do not occur, and a tensile strain of 1% or more Hard to occur. The water / binding material ratio specifically means water / (cement + admixture).

  On the other hand, when the sand binder ratio exceeds 1.5, the elastic modulus and fracture toughness of the matrix are increased for PVA fibers, and multi-cracks are not generated, and tensile strain of 1% or more is hardly generated. Therefore, in the case of using the fiber of [F1], the water binder ratio is 25% or more, preferably 30% or more, and the sand binder ratio is 1.5 or less. However, even in the case of this blended matrix, if the blending amount of [F1] fiber is 1 vol. However, even if blended too much, the effect is saturated, so 3 vol.

  Even with this fiber blending amount, if the fiber length is less than 5 mm, multi-cracks do not occur, so it is necessary to use a fiber having a length of 5 mm or more. However, even if a material longer than 25 mm is used, multi-cracking does not occur with the above blending amount. Therefore, the length of the fiber of [F1] needs to be 5 to 25 mm, preferably 6 to 20 mm, and more preferably 8 to 15 mm.

Preferably, the aggregate has a maximum particle size of 0.8 mm or less and an average particle size of 0.4 mm or less in order to ensure an appropriate amount of powder. If necessary, part of the cement is replaced with an admixture such as fly ash or blast furnace slag. In some cases, by adding a water retention agent mainly composed of a urethane resin in a range of 20 kg / m ³ or less, the table flow value can be increased and material separation can be more reliably prevented.

  In addition, when the water binder weight ratio (W / C) is 25% or more, it is effective to improve the workability of mortar spraying.

The present invention is based on the condition [M1] of the formulation matrix [M1], as shown in FIG. 1, according to the property of the repair surface and the gradient condition, the thickener And the amount of the high-performance AE water reducing agent added are adjusted according to the matrix in Table 1 below and mixed.

  The high-performance AE water reducing agent is mainly composed of a polycarboxylic acid ether compound.

  The thickener is selected from water-soluble polysaccharides, welan gum, detan gum, microbial cells, mixed proteins, and glycols, with welan gum being preferred.

  Welan gum is a microbial fermented polysaccharide produced by the strain number Alcaligenes ATTC 31961. In each case, powdered welan gum sold by Sanki Co., Ltd. is added in the indicated amount. HEC represents hydroxyethyl cellulose, and uses the product name Fujichemi HECAV-15F manufactured by Sumitomo Seika Co., Ltd.

In the matrix of Table 1, θ = 90 degrees (vertical construction) has the same amount of thickening agent (3-5 kg / m ³ ) as compared to θ = 180 degrees (for ceiling), and has a suitable high performance. The reason why the amount of the AE water reducing agent is large is that 180 degrees (for ceiling) is the most severe condition, and the amount of the high-performance AE water reducing agent is smaller than that for the vertical at 90 degrees with respect to the amount of the thickener. Otherwise, sagging will occur.

  As an embodiment of the present invention, an example of a steel bridge pier foundation repair method will be described. FIG. 2 is an explanatory view of a repair method for a steel pier foundation, and shows a structure in which a steel pier foundation 1 of a bridge is rooted on a root concrete 2.

An example of the composition of the repair material (ECC) 6 is shown in Table 2 below.
Premix material = Hardened cementitious composite (ECC)
Liquid admixture A = High performance AE water reducing agent (mainly composed of polycarboxylic acid ether compound)
Liquid admixture B = shrinkage reducing agent (based on polyoxyalkylene monoalkyl ether)
Liquid admixture C = air conditioning agent (based on polyoxyalkylene monoalkyl ether)

  When the process is shown in FIG. 3, it consists of application of an adhesive material and coating of a repair material, the repair height is about 15 cm to 20 cm, and, as a pretreatment, when the material of the repair surface is made of steel, A resin composition as a base material is combined with an external means for forming roughness for ensuring adhesion strength.

  Before applying the adhesive material 5 to the repair surface made of steel, the surfaces of the steel pier foundation 1 and the root-wrapped concrete 2 are preliminarily bonded as an external means for forming a roughness for ensuring a predetermined adhesion strength. Keep it.

  Subsequently, the adhesive material 5 which mix | blended quartz sand as an aggregate with the highly durable epoxy resin adhesive is apply | coated to the repair location of the steel pier base part 1 of a bridge.

As a highly durable epoxy resin adhesive, there is no decrease in strength in a 2 million times fatigue test under water-filled conditions, a compressive strength of 50 MPa or more, a compressive elastic modulus of 1000 MPa or more, a bending strength of 35 MPa or more, and a tensile shear strength of 10 MPa or more. Use a highly durable epoxy resin adhesive (trade name: KS Bond, non-registered trademark Kashima Road Co., Ltd.) that has a residual tensile strength of 90% or more under the exposure condition of treatment condition E or breaks the base material.

  As the chemical composition of the high durability type epoxy resin adhesive, it is preferable that the main agent is a bisphenol-based epoxy resin and the curing agent is a modified aliphatic polyamine, but it may be other chemical composition.

JIS standard sand is used for the silica sand as an aggregate, and 1000 g of silica sand is mixed with 1500 g of a highly durable epoxy resin adhesive (KS bond).
Tables 3 and 4 below show examples of standard sand quality.
(Remarks) 1) Analytical method: Cement Association standard test method I-12-1981 (Scientific analytical method for siliceous raw materials)
2) Analytical values are on a dry basis. Drying conditions are 105 ° C. and 1 hour.

  When the high durability epoxy resin adhesive and silica sand are applied as a premix, the variation in quality is reduced. However, it is also possible to spray the silica sand after applying the high durability epoxy resin adhesive.

  A high toughness cement composite material (ECC: Engineered Cementitious Composite) composed of this adhesive material 5 and water, a hardened cementitious composite material, a high performance AE water reducing agent, a shrinkage reducing agent, and an air conditioning agent. The repair material 6 is coated on the repair surface with plastering to ensure a predetermined thickness.

  The repair material (ECC) 6 is kneaded with a hand mixer and applied to the repair surface with a plasterer, or by installing and pouring a formwork to ensure a predetermined thickness, it is coated for a short time (3 hours) Plastering without the installation and removal of the formwork is suitable for finishing with a degree.

  The repair material (ECC) 6 has a predetermined thickness of 6 mm, preferably 10 mm or more. If it is thinner than this, performance deteriorates.

  In addition, the chamfer finish 8 which does not leak water is used for the top end finish in the coating construction.

  After coating the repair material (ECC) 6, a coating curing agent (RIS211E, manufactured by Denka) was sprayed to prevent initial drying.

  Next, experimental results for confirming the effects of the present invention will be described. First, regarding the pros and cons of repairing material (ECC) 6, apply adhesive material 5 to a steel panel as shown in Fig. 4, and then apply repairing material (ECC) 6 to 10mm in the manner of plastering from above. Although it was constructed with a degree, it was confirmed that the plastering could be done sufficiently without any material sagging.

  About water-impervious evaluation of repair material (ECC) 6, the water permeability test of repair material (ECC) 6 which generated the fine crack was implemented. In the experiment method, a specimen having a diameter of 100 mm and a height of 15 mm was subjected to a water permeation test by introducing a crack into the specimen by a split test and then applying a pressure of 15 kPa. During the splitting test, a π-type gauge was attached, and loading was performed until the strain reached 1000 μm.

  In the water permeability test, an output method was adopted, the test time was set to 24 hours or longer, and the test was conducted until the water permeability per hour was stabilized, and the water impermeability was evaluated based on the water permeability.

[Experimental result]
FIG. 5 shows the relationship between the amount of water per time and the elapsed time of the specimen of the repair material (ECC) 6 and the mortar specimen. From these figures, the water permeability of the repair material 6 was very small compared to the mortar. This is thought to be because the crack width of the repair material 6 was controlled within a fine range.
FIG. 6 shows, as a photograph, the state of crack expansion after completion of the test in a specimen of repair material (ECC) 6 into which strain was introduced. As shown in the photograph, in the case of the repair material (ECC) 6, since the cracks were filled with white precipitates, in the ECC shot specimen, fine cracks were filled with precipitates. Thus, it is considered that the water permeability decreased with time. From the above test results, it was confirmed that the repair material (ECC) 6 has a very high water barrier property.

  In the present invention, the adhesive material 5 is a mixture of silica sand and used to ensure the adhesion between the repair material 6 and the steel plate, and the adhesion of the repair material (ECC) 6 by this method was evaluated.

  In the experiment method, an adhesive material 5 in which silica sand is mixed in advance is applied to a 1 m × 1 m steel plate, and the repair material 6 is driven in a thickness of 10 mm. Then, the sealing curing for 28 days was performed and the adhesion test by the Kenken type tensile tester 7 (FIG. 7) was done.

[Experimental result]
Table 5 below shows a list of tensile test results. The average value of the data obtained by removing the maximum value and the minimum value from the 8 data is shown. All the peeled parts are peeled off from the repair material (ECC) 6 part, and the adhesion strength is 2.0 N / mm ² or more, so it is confirmed that the adhesion of the adhesive material 5 is sufficiently secured. It was.

  Since there is a concern about the ingress of water from the adhesion interface between the steel plate and the repair material (ECC) 6, the water shielding property of the interface was evaluated. As an experimental method, a water permeability test is carried out in order to confirm the water barrier property of the interface. The water permeation test was an output method, and the specimen had a size of φ100 mm × h100 mm as shown in FIG. 8 and a repair material (ECC) 6 was driven so as to sandwich the steel plate. An adhesive material 5 in which silica sand is mixed in advance is applied to the interface between the steel plate and the repair material (ECC) 6. The specimen was cured after the implantation of the repair material (ECC) 6 with a standard curing of 28 days. A specimen was placed in a pressure vessel for a water permeability test, and the gap was sealed using an epoxy resin and a caulking material. After the lid was attached to the pressure vessel and sealed, water was poured into the pressure vessel and pressure was applied using a compressor. The loading pressure was 0.05 MPa and the loading time was 24 hours.

[Permeability test results]
The water permeation amount after 0.05 MPa and the loading time of 24 hours was 0 ml in all three specimens, so it was confirmed that the water shielding property at the interface was sufficiently secured.

As a test construction, in order to conduct a thickness reduction investigation in advance, the hanging work and the keren work (about 3 types of keren) of the neck wound concrete were carried out to remove rust and dirt. Keren work site was about 100mm from the top of the root winding concrete.
Next, a high durability type epoxy resin adhesive [trade name KS Bond (manufactured by Kashima Road Co., Ltd., two-component mixed type)] is used as the adhesive material 5 and the silica sand is mixed in advance using a brush or the like. Applied.
In the manufacture of the repair material (ECC) 6, a mixer was used and 32 L × 2 batches were mixed. A finishing ruler with magnet was attached to the steel bridge pier, and construction was performed with a gold trowel.
The finish of the top end was made into a shape that does not stagnate. For this finishing, a chamfering finish 8 is made using a chamfering iron. After completion of the placement of the repair material (ECC) 6, a coating curing agent (RIS211E, manufactured by Denka) was sprayed on the placement site to prevent initial drying.

Table 6 below shows the quality standards of the repair material 6 in the room and test construction as quality control of the test construction. In the laboratory test, the amount of air was confirmed, and in the test construction, the tensile and compressive strengths were confirmed.
(1) Fresh property test result Table 7 shows the fresh property test result. All the items satisfied the target values.
(2) Compressive strength test results The compressive strength test results at the age of 28 days are shown in Table 8 below. From the test results, the target value was 30 N / mm ² or more.
(3) Tensile strength test results In the tensile strength test, an autograph tester (maximum load 50 kN) manufactured by Shimadzu Corporation shown in FIG. 9 was used. The results of the tensile test are shown in Table 9 below and FIG. The tensile yield strength and ultimate ultimate strain both satisfied the target values.

It is explanatory drawing which shows the relationship between the angle of a repair surface, and the addition amount of an admixture. It is explanatory drawing in the case of applying this invention to repair of a steel pier base part. It is a flowchart which shows the process of this invention. It is a perspective view which shows the outline | summary of a workability confirmation test. It is a graph which shows the relationship between the elapsed time of repair material (ECC), and the amount of water permeability. It is explanatory drawing which shows the crack expansion condition after completion | finish of the test in the specimen of repair material (ECC). It is explanatory drawing of a tensile tester. It is a perspective view which shows the outline | summary of a test body. It is explanatory drawing of an autograph testing machine. It is a graph which shows the relationship between the stress and the strain in a direct-axial tensile test.

DESCRIPTION OF SYMBOLS 1 ... Steel pier base part 2 ... Neck winding concrete 5 ... Adhesive material 6 ... Repair material 7 ... Tensile tester 8 ... Chamfering finish

Claims (6)

It is a repair method using a curable cementitious composite material that applies a curable cementitious composite material to the repair surface.
The curable cementitious composite material is blended with PVA short fibers that satisfy the following [F1] in a preparation matrix that satisfies the following [M1]
In accordance with the nature of the repair surface and the gradient conditions, the addition amount of the thickener and the high-performance AE water reducing agent is adjusted according to the following matrix table so that the viscosity can be plastered.
Use Compressive strength at the age of 28 days is 30 N / mm ² or more, a tensile yield strength of 2.0 N / mm ² or more, the hardening cement-based composite materials, characterized in that a tensile ultimate strain of 0.2% or more There was a repair method.
[M1]
Using ordinary Portland cement or low heat Portland cement, water binder weight ratio: 25% or more, unit water volume: 250-400 Kg / m ³ , fine aggregate binder weight ratio (S / C): 1.5 or less (including 0) ), Maximum particle size of fine aggregate: 0.8 mm or less, average particle size of fine aggregate: 0.4 mm or less, expanded material: less than 100 Kg / m ³ [F1]
Fiber diameter: 50 μm or less, fiber length: 5 to 25 mm, fiber tensile strength: 1500 to 2400 Pa, fiber amount: more than 1 to 3 vol.%
Thickeners, repairing method using welan, the hardening cement-based composite material according to claim 1, wherein selecting either Deyutanga beam et al. If the material before Symbol repaired surface is made of steel, pre-treated as, combining the resin composition as an external unit and the base material to form a roughness in order to secure a predetermined attachment strength claim 1, wherein Item 3. A repair method using the curable cementitious composite material according to Item 2 .   The repairing method using the hardened cementitious composite material according to claim 3, wherein the external means for forming the roughness is kelen. The repair method using the curable cementitious composite material according to claim 1 or 2, wherein a resin composition is used as a base material when the material of the repair surface is made of concrete. As the resin composition, there is no strength reduction in the 2 million times fatigue test under water-filled conditions, the compressive strength is 50 MPa or more, the compression elastic modulus is 1000 MPa or more, the bending strength is 35 MPa or more, and the tensile shear strength is 10 MPa or more. The repair method using the curable cementitious composite material according to any one of claims 3 to 5, wherein a high-durability epoxy resin adhesive having a residual tensile strength of 90% or more under exposure conditions or destroying a base material is used.