WO2007111452A1

WO2007111452A1 - Reinforcing methods using as silane modified epoxy composition for underwater structure

Info

Publication number: WO2007111452A1
Application number: PCT/KR2007/001452
Authority: WO
Inventors: Ju Ho Kwak
Original assignee: Consco.Co., Ltd; Conclinic Co., Ltd.; Kunil Engineering Consultants Co., Ltd.
Priority date: 2006-03-25
Filing date: 2007-03-23
Publication date: 2007-10-04
Also published as: KR100594508B1

Abstract

The present invention relates to a repairing and reinforcing composition capable of sufficiently maintaining adhesive force by injecting it into a deteriorated part of an underwater structure or by impregnating a glass fiber, a carbon fiber or an aramid fiber with the repairing and reinforcing composition so as to use it as a repaired and reinforcing material, and a repairing and reinforcing method using the same. The present invention provides a water curing silane modified epoxy composition having an increased adhesive force for repairing and reinforcing a civil or architectural structure in underwater or humid area using a silane modified epoxy composition for repairing and reinforcing an underwater structure comprising an epoxy base material (A) comprising a bisphenol A epoxy resin, a bisphenol F epoxy resin, a silane- modified acrylic polymer compound, an aliphatic difunctional reactive diluent, and an inorganic filler, and a curing agent (B) comprising a polyamideamine type curing agent, a modified aliphatic polyamine, a modified alicyclic amine, an aminosilane compound, and a nonylphenol.

Description

REINFORCING METHODS USING AS SILANE MODIFIED EPOXY COMPOSITION

FOR UNDERWATER STRUCTURE

[Technical Field]

The present invention relates to a silane modified epoxy composition for repairing and reinforcing an underwater structure and a method for repairing and reinforcing an architectural or civil structure which exists underwater, and more particularly, to a repairing and reinforcing method for recovering a lowered resisting force by injecting a silane modified epoxy resin into a deteriorated part of an underwater structure or by adhering the silane modified epoxy resin to a surface of a structure to be repaired and reinforced using a glass fiber, a carbon fiber or an aramid fiber.

[Background Art]

A method for repairing and reinforcing a structure, where a deterioration or corrosion is occurred, using a fiber such as a carbon, a glass and an aramid not only increases a strength of an existing structure, but also provides a function of restricting the deterioration of the structure so as not to occur any more by protecting a surface of the structure. At this time, an adhesive for adhering a reinforcing fiber and an adhesion surface is important to make the reinforcing fiber and the existing concrete-steel structure to exhibit same mechanical behavior. In this case, an epoxy resin is generally used as a material of the most widely used adhesives, but it is impossible for the general epoxy resin to adhere to the target structure and the reinforcing fiber and exhibit strength in underwater.

Such repairing and reinforcing material of the present invention is used in a repairing and reinforcing using fiber, a coating of a concrete-steel pile, an adhesion of a fiber to a pile, a crack injection by an underwater pressure injection and the like, in which a repairing and reinforcing material such as a coating agent, a grouting agent, a patching agent, a primer for adhering fiber and an impregnant of epoxy base does not generate a separation of material in underwater and thus capable of repairing and reinforcing perfectly and maintaining efficiently a damaged concrete structure in underwater or a humidity surface .

Recently, in a civil or architectural structure of a reinforced concrete, lowering in a compressive strength of the concrete due to various deterioration phenomena such as an exfoliation, a peeling off and an abnormal crack and a tensile strength due to a corrosion of the reinforcing steel causes a damage and a resultant breakdown of a reinforced concrete, and a problem of an accident such as a breakdown of a structure due to the corrosion of the reinforcing steel within a reinforced concrete structure is reported from newspapers and TVs and thus becomes to a significant social problem. A deteriorating factor of a concrete or a main cause of the deterioration phenomenon is as follows: a corrosion of the reinforcing steel does not occur since the concrete is strong alkaline (ph = 12.5), however the corrosion of the reinforcing steel occur as a neutralization is occurred in the concrete due to carbonic acid gas, acidic material, penetration of chloride, alkali-aggregate reaction, atmospheric condition (expansion/contraction and penetration of rainwater) , and thus a crack is generated in the concrete due to an expansion of rust and the reinforced concrete structure is broken by an exfoliation and a peeling off thereby resulting in a breakdown of the structure.

In addition, lowering in a load carrying capacity of a structure due to a crack of a concrete and a corrosion of a reinforcing steel as the concrete structures including various civil and architectural structures are neutralized by penetration of carbon dioxide and acid rain is known to be accelerated not only by the penetration of carbon dioxide but also by the neutralization of the concrete in a case that gravels and sands which are mixed to the concrete are volcanic rocks.

Particularly, when repairing and reinforcing a pier, a pier caisson and an underground construction in a humid condition, there was a problem that repairing and reinforcing ability is lost by an exfoliation and a falling off of the repaired and reinforced part since adhesive force between a damaged part in underwater or humid condition and a repairing and reinforcing material is weak and thus they are not integrated and are cured in a slack state. In addition, there was a significant problem that the repairing and reinforcing material is apt to be carried away by a flow speed in a case of a pier where the water flows.

Generally, an exfoliation, a falling off and a deterioration of materials are occurred in an underwater concrete structure by scour and erosion due to an influence of sea water and collisions with ships and the like. Reinforcement has conventionally been carried out with general mortar, concrete and epoxy resin in order to reinforce the above . However, in a case of using the above materials, the repairing and reinforcing materials are exfoliated and fallen off and thus the repairing and reinforcing effect is very minute since the materials can not be integrated with existing concrete, have a weak adhesive force in relation to a humid place or underwater damaged part and cured in a slack state after carrying out due to a difference in a coefficient of thermal expansion.

Korean Patent Laid Open No. 2001-0104120 discloses a repairing agent composition for repairing, sealing and reconstructing crack parts of civil and architectural structures which require a rapid maintenance, containing a poly mercaptane curing type epoxy resin consisting of a mixture of metal fillers or mixed composition of inert inorganic powder, however does not teach a coating and an adhering to a concrete surface in underwater.

Korean Patent Laid Open No. 2006-0009412 discloses a water curing two-pack type epoxy paint composition including a modified epoxy resin properly containing a bisphenol A epoxy resin, a modified petroleum resin, a swelling dispersant, an extender pigment and a coloring pigment, and an amine curing agent properly containing isophorone diamine (IPDA) , norbornene diamine (NBDA) , benzyl alcohol and a bisphenol A epoxy resin, and a method preparing the same. However, there is a limitation in repair since the reinforcement is not carried out directly to a structure in underwater when the underwater concrete structure or steel structure is damaged.

[Disclosure] [Technical Problem]

An object of the present invention, to solve the above problem that the repairing and reinforcing materials are exfoliated and fallen off and thus the repairing and reinforcing effect is very minute since the materials can not be integrated with existing concrete, have a weak adhesive force in relation to a humid place or underwater damaged part and cured in a slack state after carrying out due to a difference in a coefficient of thermal expansion, is to provide a composition for repairing and reinforcing an underwater structure having a novel composition including an epoxy resin as a base material so as to give a strong adhesive force to a surface to be repaired and reinforced and a repairing and reinforcing material and have high strength so as not to generate separation of materials on humid surface or in underwater. In addition, further object of the present invention is to provide a method for repairing and reinforcing a structure capable of directly repairing and reinforcing an underwater structure by using the above repairing and reinforcing composition in various manners of directly coating a surface to be repaired and reinforced, injecting it into a damaged portion such as a crack or impregnating a fiber material with it to adhere or so on, in underwater. [Technical Solution]

The present invention relates to a repairing and reinforcing composition capable of sufficiently maintaining adhesive force by injecting it into a deteriorated part of an underwater structure or by impregnating a glass fiber, a carbon fiber or an aramid fiber with the repairing and reinforcing composition so as to use it as a repaired and reinforcing material, and a repairing and reinforcing method using the same. The inventor accomplished the present invention by finding that a tensile strength is significantly increased after an underwater curing when adding a silane modified epoxy compound to bisphenol A type and bisphenol F type epoxy compositions, adjusting viscosity with an aliphatic difunctional reactive diluent and adding a predetermined amount of an aminosilane to a curing agent.

An epoxy composition adherable to a concrete-steel surface and a repairing and reinforcing material should be smoothly cured even at a low temperature, should have a sufficient pot life and be capable of underwater working by maintaining a predetermined viscosity when mixing an epoxy base material with a curing agent on the ground, and should not be dissolved in water and be capable of being coated on the concrete-steel surface in underwater. The present invention, which satisfies the above requirements, is a silane modified epoxy composition for repairing and reinforcing an underwater structure, comprising 100 parts by weight of an epoxy base material (A) comprising a bisphenol A epoxy resin 25-50wt%, a bisphenol F epoxy resin 3- 20wt%, a silane-modified acrylic polymer compound 5-20wt%, an aliphatic difunctional reactive diluent l-15wt%, and an inorganic filler 10-30wt%, and 40-70 parts by weight of a curing agent (B) comprising a polyamideamine type curing agent l-15wt%, a modified aliphatic polyamine 10-40wt%, a modified alicyclic amine 30-70wt%, an aminosilane compound 5-30wt%, and a nonylphenol l-17wt%.

The present invention will be described in detail hereinafter. A function of each component of the base material is as follows.

First, components contained in the epoxy base material (A) will be described.

In the present invention, a bisphenol A type epoxy resin and a bisphenol F type epoxy resin are used as an epoxy resin; it is possible to use a general bisphenol A type product as the bisphenol A type epoxy resin and is preferable to use it in a range of 25-50wt% and it is also possible to use a general bisphenol F type product as the bisphenol F type epoxy resin and is preferable to use it in a range of 3-20wt%. The bisphenol A epoxy resin performs a function that a cured body of the epoxy composition exhibits an adhesive force and strength to a concrete structure or a steel structure. There is a problem of lowering in the adhesive force and the strength if used less than 25wt% and there is a problem that the epoxy composition is aggregated in underwater, thus lumped on a surface when coated to a concrete structure or a steel structure and consequently workability is significantly lowered, if used more than 50wt%. The bisphenol F epoxy resin is used to for the purpose of complementing a physical property of the bisphenol A type epoxy resin and performs a function that the epoxy composition is smoothly coated to a concrete or a steel structure in underwater. It is preferable to use the bisphenol F epoxy resin in the above amount range since workability is lowered as it is significantly increased a occurrence of the phenomenon that the epoxy composition is contracted to be aggregated in underwater if an amount of the bisphenol F type epoxy resin is less than 25wt%, and there is a problem of lowering in the adhesive force to a concrete structure or a steel structure if used more than 20wt%.

In the present invention, the silane-modified acrylic polymer compound is used to increase an adhesive force to a concrete in underwater. As a solvent thereof may be selected at least one selected from an epoxy reactive diluent containing at least two epoxy functional groups such as neopentylglycol diglycidylether and alkylsilane such as tetraethoxysilane (TEOS) and tetramethoxysilane (TMOS) . In addition, the silane-modified acrylic polymer compound is obtained by copolymerizing a composition comprising the above solvent mixture 20-40wt%, methylmethacrylate 20-60wt%, butylacrylate 10-40wt%, glycidylmethacrylate 5-15wt%, and vinyltriethoxysilane, vinyltrimethoxysilane or 3- methacryloxypropyltrimethoxysilane 3-25wt%.

At this time, the solvent mixture may comprise at least one selected from neopentylglycoldiglycidylether, triethylolpropanetriglycidylether, polypropyleneglycoldiglycidylether, 1, 4-butandiol diglycidylether, 1, 6-hexanediol diglycidylether. It is preferable to use the solvent mixture in the above amount since there are problems that a viscosity of the copolymer is excessively high to cause an inconvenience in use if the amount thereof is less than 20wt%, and an amount of the reactive diluent or the alkylsilane is increased, a viscosity of the resultant epoxy composition is lowered and thus the epoxy composition runs down when coated onto a wall in underwater if the amount thereof is more than 40wt%.

It is preferable to use the methylmethacrylate in the above amount since workability is lowered as a hydrophilic property of the polymer is lowered and thus the epoxy composition is apt to be aggregated in underwater when mixed to the epoxy composition if the amount of the methylmethacrylate is less than 20wt%, and a tensile strength is increased but an impact strength is lowered when curing the final epoxy composition if the amount of the methylmethacrylate is more than 60wt%. On the other hand, the butylacrylate has a property contrary to that of the methylmethacrylate and thus exhibits a problem that an adhesive force and an impact strength is lowered if used less than 10wt% and workability is lowered when coating in underwater if used more than 40wt%.

The glycidylmethacrylate is a monomer which is introduced to derive a curing reaction together with the bisphenol A type and F type and an amine based curing agent by introducing an epoxy functional group into the copolymer and exhibit a problem that the strength is lowered as a degree of cure is low when forming the epoxy curing agent if the amount thereof is less than 5wt% while it is difficult to polymerize as a gelation is occurred when synthesizing the copolymer if the amount thereof is more than 15wt%.

The monomer containing a silane such as the vinyltriethoxysilane, vinyltrimethoxysilane or 3- methacryloxypropyltrimethoxysilane performs a function that derive a coupling reaction with a concrete wall or a reinforcing fiber to exhibit a strong adhesive force and increases an adhesive strength to the concrete wall in underwater. At this time, it is preferable to use it in the above amount range since the effect is minute if used less than 3wt% while it is difficult to polymerize as a gelation is occurred when synthesizing the copolymer if used more than 25wt%. The copolymer made by the above composition comes to participate in an epoxy curing reaction since it has an epoxy functional group in a polymer base material, and increases an adhesive force to a reinforcing fiber since it has a methoxy- or ethoxysilane functional group. In addition, a difunctional reactive diluent such as neopentylglycoldiglycidylether, and tetraethoxysilane (TEOS) and tetramethoxysilane (TMOS) which are used as a solvent perform a function that promotes a curing reaction even at a low temperature when mixed in the curing agent, and improves an acid resistance and a chemical resistance after the cure. It is preferable to use 5-20wt% of the copolymer; an adhesive strength between a concrete and a reinforcing fiber is reduced in underwater if used less than 5wt% and the adhesive strength to a concrete is increased while an adhesive strength to a steel plate and workability in underwater is lowered if used more than 20wt%.

In the present invention, the aliphatic multifunctional reactive diluent is used to maintain a suitable viscosity which is necessary to work and it is preferable to use neopentylglycoldiglycidylether as the aliphatic multifunctional reactive diluent. Besides, triethylolpropanetriglycidylether, polypropyleneglycol diglycidylether, 1, 4-butandiol diglycidylether, 1, 6-hexanediol diglycidylether and so on may also be used. In the present invention, the inorganic filler is used to increase strength of the final cured body of an epoxy and maintain smooth workability, and exemplary includes, not limited to if it is a generally used one, at least one selected from titanium dioxide, clay, calcium carbonate (CaCO₃) , fumed silica, talc and aluminum hydroxide. It is preferable to be used in an amount of 10-30wt% since there is a disadvantage that an aggregation is highly occurred and thus workability is lowered as an amount of polymer is large in the epoxy composition if used less than 10wt% while there is a problem that an adhesive performance to a concrete or steel structure is lowered if used more than 30wt%.

Components of the curing agent will be described hereinafter.

The curing agent of the present invention includes, as its components, a polyaraideamine type curing agent l-15wt%, a modified aliphatic polyamine 10-40wt%, a modified alicyclic amine 30-70wt%, an aminosilane compound 5-30wt%, and a nonylphenol l-17wt%. The polyamideamine type curing agent, the modified aliphatic polyamine, the modified alicyclic amine perform a function that react with an epoxy resin of the base material to generate a mixed epoxy and determine finally physical property and adhesive property, and the aminosilane increases an adhesive force and strength between a concrete and a reinforcing fiber with a coupling action, and the nonylphenol promotes a curing and acts to reduce an absorption of water after cure as a water repellent function is added thereto.

The polyamideamine type curing agent is a kind of a polyamideamine resin and is the most general shape of curing agents for an epoxy and is not limited to be used if it is a conventionally used one by a person skilled in the art. The polyamideamine type curing agent performs a function that reacts with an epoxy resin to form an epoxy cured body and exhibit strength of the cured body. A range of the amount of the polyamideamine type curing agent in this invention is good for strength and adhesive force of a composition of the cured body.

The modified aliphatic polyamine curing agent is for giving smooth workability and a performance of adhering without aggregation in underwater and it is preferable to use curing agent having a viscosity of approximate 2000-4000cps in order to maintain the final viscosity. As such product, there is KH-240, KH-240-R available from Kukdo Chemical Co., Ltd. or EPH137, EPH177 available from Hexion Specialty Chemicals, Inc and so on. It is preferable to use EPH177 for an impregnation and it is preferable to use EPH137 for a primer or direct coating in view of adjusting viscosity. Furthermore, an amount of the modified aliphatic polyamine curing agent is preferably 10-40wt%; there is a problem of lowering in workability in underwater if used less than 10wt% and the final composition is apt to be dissolved in water as a hydrophilic property comes to be strong and an adhesive performance to a surface of a concrete or steel structure is lowered if used more than 40wt%.

The modified alicyclic amine curing agent is used for improving an adhesive performance in underwater. At this time, it is preferable that its viscosity is 1000-3000cps and its amine value is 300-360 and a product satisfying above condition is KH-817 available from Kukdo Chemical Co., Ltd. It is preferable that an amount thereof is 30-70wt%; an underwater adhesive force is lowered if used less than 30wt% and an adhesive strength is lowered as dissolving in underwater becomes more serious if used more than 70wt%.

The aminosilane compound is used for increasing strength and may include at least one selected from 3- aminopropyltriethoxysilane, n- (2-aminoethyl) -3- aminopropyltrimethoxysilane and n- (2-aminoethyl) -3- aminopropylmethyldiethoxysilane, preferably include n- (2- aminoethyl) -3 -aminopropyltrimethoxysilane. An amount thereof is 5-30wt%; a coupling action is minute and thus the effect is small if used less than 5wt% while a physical property is lowered as a degree of cure is lowered if used more than 30wt%.

The nonylphenol is used as a plasticizer. An amount of this invention good for workability, hardness and adhering strength of the composition of the cured body.

The silane modified epoxy composition of the present invention is divided into two kinds according to a use. The one is a shape that can be used as a primer for an underwater vertical surface, can be coated directly to an architectural structure or a steel structure in underwater using a roller or a brush or can be injected into a crack part (hereinafter, referred as CAUW-PR) , and may be mixed with fine aggregates to be used in a patching. At this time, a preferable viscosity of the silane modified epoxy composition is 14 , 000-18 , OOOcps .

The other is a shape that the silane modified epoxy composition in a state of a low viscosity is impregnated to be used into a carbon fiber, a glass fiber, or an aramid fiber (hereinafter, referred as CAUW-SR) . At this time, a preferable viscosity of the silane modified epoxy composition is 9,000- 11, OOOcps . The silane modified epoxy composition for repair and reinforcement of the present invention is manufactured by mixing the above base material and the above curing agent in a rate of 40-70 parts by weight of the curing agent per 100 parts by weight of the base material, preferably 50-60 parts by weight of the curing agent per 100 parts by weight of the base material. A viscosity of the composition according to the present invention is preferably 9, 000-18, OOOcps .

The silane modified epoxy composition for repairing and reinforcing an underwater concrete structure manufactured by the present invention is applicable to a structure which is laid underwater and may be used in a harbor structure such as an underwater caisson, a concrete pile, a steel pipe pile, a pier type wharf, and a sewage or rainwater box and the like.

The method for repairing and reinforcing an underwater structure using the silane modified epoxy composition of the present invention includes a method of directly coating to an architectural structure or a steel structure in underwater using a roller or a brush, a method of impregnating a fiber selected from a glass fiber, a carbon fiber and an aramid fiber with the silane modified epoxy composition 0.8-1.5kg/m² and adhering it to a target structure in underwater, and a method of injecting the silane modified epoxy composition. The composition according to the present invention is applicable to an underwater structure in various manners as it has a viscosity and a physical property capable of adhering in underwater.

[Best Mode] Hereinafter, the embodiments of the present invention will be described in detail. However, it will be appreciated that those skilled in the art, on consideration of this disclosure, may make modifications and improvements within the spirit and scope of the present invention. [Manufacturing Example 1]

Manufacturing of a silane-modified acrylic polymer compound containing an epoxy functional group (hereinafter, referred as CONS-EP)

30Kg of mixed solvent, in which tetraethoxysilane (Dow Corning Corporation, USA) and neopentylglycol diglycidylether

(Hexion Specialty Chemicals, Inc, product name: 710) are mixed in a weight ratio of 2:8, was put into a reactor and then was copolymerized at 8O⁰C for 4hours using 3- methacryloxypropyltrimethoxysilane (Chisso Corporation, Japan) 10Kg, methylraethacrylate (Honara Petrochemical Corporation, product name: MMA) 40Kg, butylacrylate (LG chem., ltd., product name: BA) 20Kg and glycidylmethacrylate (Mitsubishi Rayon co., ltd., Japan, product name: GMA) 10Kg. At this time, 0.2Kg of AIBN was used as a reaction initiator. After 4hours of reaction, 0.1Kg of AIBN which is a reaction initiator was additionally putted into the inside of the reactor and then the reaction was continued at 80⁰C for 2hours . The resulting compound was in transparent liquid phase, a viscosity thereof was 8400cps/23°C (Brookfield viscometer, spindle #5) and a reaction yield thereof was 99.98%.

[Example 1]

Manufacturing of an epoxy base material (A) A base material was manufactured by mixing a bisphenol A epoxy resin (Kukdo Chemical Co., Ltd., YD-128) 42wt%, a bisphenol F epoxy resin (Kukdo Chemical Co., Ltd., YD-165) 16wt%, the silane-modified acrylic polymer compound (CONS-EP) which was manufactured in the manufacturing example 1 10wt%, neopentylglycol diglycidylether (Hexion Specialty Chemicals, Inc, product name: 710) 8wt%, titanium dioxide 5wt%, talc 3.5wt%, calcium carbonate (CaCO₃) 7wt% and fumed silica 8.5wt%. Manufacturing of a curing agent (B) A curing agent was manufactured by mixing the polyamideamine type curing agent (Kukdo Chemical Co., Ltd., G- 331) 15wt%, a modified aliphatic polyamine curing agent (Kukdo Chemical Co., Ltd., KH-240) 20wt%, a modified alicyclic amine (Kukdo Chemical Co., Ltd., KH-817) 50wt%, a nonylphenol 10wt% - and a n- (2-aminoethyl) -3-aminopropylmethyldiethoxysilane (Chisso Corporation, Japan, product name: S-310) 5wt%.

Manufacturing of a silane modified epoxy composition 100 parts by weight of the base material (A) and 56 parts by weight of the curing agent which were manufactured as above described respectively, were mixed at 73°F (23⁰C), whereby a repairing and reinforcing material for an underwater concrete structure CAUW-PR according to the present invention, of which viscosity is 16, 000cps/23°C (Brookfield viscometer, spindle #5) , was manufactured.

[Example 2]

Manufacturing of an epoxy base material (A) A base material was manufactured by mixing the bisphenol A epoxy resin which was used in the example 1 40wt%, the bisphenol F epoxy resin which was used in the example 1 12wt%, the silane-modified acrylic polymer compound (CONS-EP) which was manufactured in the manufacturing example 1 14wt%, neopentylglycol diglycidylether (Hexion Specialty Chemicals, Inc, product name: 710) 10wt%, titanium dioxide 5wt%, talc 3.5wt%, calcium carbonate (CaCO₃) 7wt% and fumed silica 8.5wt%.

Manufacturing of a curing agent (B)

A curing agent was manufactured by mixing the polyamideamine type curing agent 15wt%, a modified aliphatic polyamine curing agent 20wt%, a modified alicyclic amine 40wt%, a nonylphenol 10wt% and a n- (2-aminoethyl) -3- aminopropylmethyldiethoxysilane 15wt%, which are the same kinds as the example 1.

Manufacturing of a silane modified epoxy composition 100 parts by weight of the base material (A) and 56 parts by weight of the curing agent which were manufactured as above described respectively, were mixed at 73⁰F (23⁰C), whereby a repairing and reinforcing material for an underwater concrete structure CAUW-SR according to the present invention, of which viscosity is 10 , 000cps/23°C (Brookfield viscometer, spindle #5) , was manufactured.

[Comparative Example 1]

Manufacturing of an epoxy base material (A) Comparative example 1 was carried out using the same product as the example 1. A base material was manufactured by mixing a bisphenol A epoxy resin 47wt%, a bisphenol F epoxy resin 21wt%, neopentylglycol diglycidylether 8wt%, titanium dioxide 5wt%, talc 3.5wt%, calcium carbonate (CaCO₃) 7wt% and fumed silica 8.5wt%.

Manufacturing of a curing agent (B)

The same curing composition as the example 1 was used.

Manufacturing of an epoxy composition 100 parts by weight of the base material (A) and 56 parts by weight of the curing agent which were manufactured as above described respectively, were mixed at 73⁰F (23°C) , whereby a repairing and reinforcing material for an underwater concrete structure according to the present invention, of which viscosity is 16, 000cps/23°C (Brookfield viscometer, spindle #5) , was manufactured.

[Comparative Example 2]

Comparative example 2 was carried out using the same product as the example 1.

Manufacturing of an epoxy base material (A) A base material was manufactured by mixing a bisphenol A epoxy resin 47wt%, a bisphenol F epoxy resin 21wt%, neopentylglycoldiglycidylether 8wt%, titanium dioxide 5wt%, talc 3.5wt%, calcium carbonate (CaCO₃) 7wt% and fumed silica 8.5wt%.

Manufacturing of a curing agent (B)

A curing agent was manufactured by mixing the polyamideamine type curing agent 15wt%, a modified aliphatic polyamine curing agent 20wt%, a modified alicyclic amine 40wt%, and a nonylphenol 10wt%, which are the same as the example 1.

Manufacturing of an epoxy composition

100 parts by weight of the base material (A) and 56 parts by weight of the curing agent which were manufactured as above described respectively, were mixed at 73°F (23⁰C) , whereby an epoxy composition, of which viscosity is 16, 000cps/23°C (Brookfield viscometer, spindle #5) , was manufactured as a comparative example 2.

[Experimental Example 1]

Physical properties were measured at 73°F (23°C) using the silane modified epoxy compositions for repair and reinforcement manufactured in the Examples 1 and 2 and the Comparative Examples 1 and 2, and the results are shown in following Table 1.

Methods and apparatuses as follows were used to measure the physical properties.

- Curing time: time taken to approach to 50, 000cps/23°C (Brookfield viscometer, spindle #5) of viscosity after manufacture of an epoxy composition

- Compressive strength: measured by ASTM D695 method

- Elastic modulus: measured by ASTM D695 method

- Compressive strength: mixed with aggregates in a weight ratio of 1:1, then measured by ASTM Cl09 method

- Hardness: measured by ASTM 2240 method

- Bending strength: measured by ASTM D790 method

- Tensile strength: measured by ASTM D638 method

- Underwater adhesive strength: measured by ASTM C882 method

[Table 1]

As shown in Table 1, the Comparative Example 1 denotes a result in the case of not containing a silane-modified acrylic polymer and the Comparative Example 2 denotes a result in the case of not containing a silane-modified acrylic polymer and not using an aminosilane in the curing agent. As shown in Table 1, in a case of manufacturing an epoxy composition using a silane-modified acrylic polymer according to the present invention, it can be appreciated that physical properties such as a compressive strength, an elastic modulus, a tensile strength and so on are good, and underwater adhesive strength is significantly different from the Comparative Examples. In the case of the Comparative Example 2 which excluded a silane- modified acrylic polymer and an aminosilane in the curing agent, the adhesive performance was not exhibited at all and exhibited a separation on the interface between a reinforcing fiber and a concrete in underwater.

[Experimental Example 2]

Chemical resistance were measured using the silane modified epoxy compositions for repair and reinforcement manufactured in the Examples 1 and 2 and the Comparative

Examples 1 and 2, and the results are shown in following

Tables 2 to 5.

The chemical resistance of the experimental body was measured after coating the composition on a concrete surface in a thick of 3Oram at a room temperature, the measurement was carried out at 4 points as follows.

1: maintaining a state of adherence with a concrete surface when contacted over δhours 2 : maintaining a state of adherence with a concrete surface when contacted over 72hours

3 : maintaining a state of adherence with a concrete surface when contacted over 7days

4 : maintaining a state of adherence with a concrete surface when contacted over 30days

[Table 2] Chemical resistance to acidic solution

Chemical resistance

Acidic

Example Example Comparative Comparative solution

1 2 Example 1 Example 2

10% acetic acid

10% chromic acid

5% phosphoric acid

10% sulfuric acid

25% sulfuric acid

[Table 3] Chemical resistance to miscellaneous solution

[Table 4] Chemical resistance to alkaline solution

[Table 5] Chemical resistance to other solutions

As shown in Tables, it could be appreciated of a superior chemical resistance of the reinforcing material according to the present invention and there is an effect of preventing neutralization of concrete when adhered to a concrete structure as having the excellent chemical resistance.

[industrial Applicability] As described above, a composition for repairing and reinforcing an underwater concrete structure is capable of making durability of underwater civil or architectural structure to be superior and thus preserving the structure semi-permanently as having advantages of having an increased adherence to a civil or architectural structure to be repaired and reinforced in underwater or water inundated area and a minimized falling off, and exhibiting superior adhesive force and strength to mortar and concrete structure even at low temperature .

Claims

[CLAIMS]

[Claim l]

A silane modified epoxy composition for reinforcing an underwater structure, comprising 100 parts by weight of an epoxy base material (A) comprising a bisphenol A epoxy resin

25-50wt%, a bisphenol F epoxy resin 3-20wt%, a silane-modified acrylic polymer compound 5-20wt%, an aliphatic difunctional reactive diluent l-15wt%, and an inorganic filler 10-30wt%, and 40-70 parts by weight of a curing agent (B) comprising a polyamideamine type curing agent l-15wt%, a modified aliphatic polyamine 10-40wt%, a modified alicyclic amine 30-70wt%, an aminosilane compound 5-30wt%, and a nonylphenol l-17wt%.

[Claim 2]

The silane modified epoxy composition for reinforcing an underwater structure as set forth in claim 1, wherein the silane-modified acrylic polymer compound is obtained by copolymerizing a composition comprising 20-40wt% of at least one solvent mixture selected from neopentylglycoldiglycidylether, triethylolpropanetriglycidylether, polypropyleneglycoldiglycidylether, 1,4- butandioldiglycidylether, 1, 6-hexanedioldiglycidylether, tetraethoxysilane and tetramethoxysilane, methylmethacrylate 20-60wt%, butylacrylate 10-40wt%, glycidylmethacrylate 5-15wt%, and vinyltriethoxysilane, vinyltrimethoxysilane or 3- methacryloxypropyltrimethoxysilane 3-25wt% .

[Claim 3]

The silane modified epoxy composition for reinforcing an underwater structure as set forth in claim 1, wherein the aliphatic difunctional reactive diluent is at least one selected from neopentylglycoldiglycidylether, triethylolpropanetriglycidylether, polypropyleneglycoldiglycidylether, 1,

4- butandioldiglycidylether and 1, 6-hexanediol diglycidylether . [Claim 4]

The silane modified epoxy composition for reinforcing an underwater structure as set forth in claim 3, wherein the aliphatic difunctional reactive diluent is neopentylglycoldiglycidylether .

[Claim 5]

The silane modified epoxy composition for reinforcing an underwater structure as set forth in claim 1, wherein the aminosilane compound consists of at least one selected from 3- aminopropyltriethoxysilane, n- (2-aminoethyl) -3- aminopropyltrimethoxysilane and n- (2-aminoethyl) -3- aminopropylmethyldiethoxysilane .

[Claim 6]

A method for reinforcing an underwater structure, comprising a step of directly coating an architectural structure or a steel structure in underwater with the composition as set forth in one of claims 1 to 5 using a roller or a brush.

[Claim 7]

A method for reinforcing an underwater structure, comprising steps of impregnating a fiber selected from a glass fiber, a carbon fiber and an aramid fiber with the silane modified epoxy composition as set forth in one of claims 1 to 5 and adhering it to a target structure in underwater.

[Claim 8]

A method for reinforcing an underwater structure, comprising a step of injecting the silane modified epoxy composition as set forth in one of claims 1 to 5 into a deteriorated part or a crack part of an underwater concrete.