An interface reinforcing coating for FRP bars and cement-based materials, a preparation method and application thereof

Abstract

The application discloses FRP bar and cement-based material interface reinforcing coating and a preparation method and application thereof, and belongs to the technical field of concrete structure reinforcement. The application solves the problem of low interface bonding strength of the existing FRP bar reinforced concrete. The interface reinforcing coating provided by the application comprises C-S-H nano seeds 20-80 parts, a continuous phase emulsion 35-55 parts, water 10-20 parts and functional additives 10-15 parts. The interface reinforcing coating provided by the application is directly coated on the surface of the FRP bar when the cement-based material is cast on site and prefabricated components are produced. The C-S-H nano seeds provide nucleation sites for cement hydration products, reduce the nucleation potential barrier, promote the generation of C-(A)-S-H gel, thereby reducing the interface porosity, reducing the interface defects, and enabling the FRP bar and the cement matrix to be physically connected through the C-(A)-S-H gel, realizing the integration of the FRP bar and the cement matrix, and improving the interface bonding strength.

Description

TECHNICAL FIELD

[0001] The application relates to FRP bar and cement-based material interface reinforcing coating and a preparation method and application thereof, and belongs to the technical field of concrete structure reinforcement. BACKGROUND

[0002] The corrosion and rust of steel bars in reinforced concrete structures lead to degradation of structural mechanical properties and reduction of durability, and make the structures fail prematurely before reaching the designed service life. Fiber reinforced polymer (FRP) has the advantages of light weight, high strength, corrosion resistance, fatigue resistance, and strong designability, and the use of FRP bars as reinforcement in concrete structures can not only avoid the durability problems caused by rust of steel bars, but also greatly improve the service performance and service life of the structures, and realize the win-win of economic and social benefits.

[0003] The bonding performance between the FRP bar and the cement concrete is a key factor affecting the mechanical properties of the FRP bar concrete structure. The smooth FRP bar transmits the bonding stress through friction between the FRP bar and the concrete, and the interface bonding strength is low. The existing researches improve the interface bonding strength between the FRP bar and the concrete through surface treatment forms such as weaving, sand blasting, grooving and ribbing, but the material properties of the FRP bar after surface treatment are reduced, which restricts the development of the FRP bar concrete structure. Therefore, the bonding mechanism between the FRP bar and the concrete is an important topic in the field of FRP bar reinforced concrete structure research. Therefore, the development of a FRP bar and cement-based material interface reinforcing coating will be beneficial to the further promotion of the FRP bar reinforcement technology. SUMMARY

[0004] The application provides a FRP bar and cement-based material interface reinforcing coating, a preparation method and application thereof, and aims at the problem of low interface bonding strength of the existing FRP bar reinforced concrete.

[0005] The technical scheme of the application is as follows:

[0006] One of the purposes of the application is to provide a FRP bar and cement-based material interface reinforcing coating. The interface reinforcing coating is composed of the following raw materials in parts by weight: C-S-H nano seeds 20-80 parts, continuous phase emulsion 35-55 parts, water 10-20 parts, and functional additives 10-15 parts.

[0007] Further limited, the interface reinforcing coating is composed of the following raw materials in parts by weight: C-S-H nano seeds 70 parts, continuous phase emulsion 45 parts, water 15 parts, and functional additives 10 parts.

[0008] Further limited, the C-S-H nano seeds are one or more of nano SiO2, nano CaCO3, nano TiO2, carbon nanotubes and nano calcium silicate hydrate (C-S-H).

[0009] Further, the C-S-H nano-seeds comprise 20 parts of nano-SiO2, 20 parts of nano-CaCO3 and 10 parts of nano-Ca (OH) 2.

[0010] Further, the continuous phase emulsion is prepared by mixing the following raw materials in the following proportions by weight: styrene 5-20 parts, methyl methacrylate 10-30 parts, hydroxyethyl acrylate 5-25 parts, n-butyl acrylate 5-25 parts, acrylic acid 5-25 parts, polyurethane 5-20 parts, potassium persulfate 5-10 parts, sodium dodecyl sulfate 5-10 parts, and water 30-50 parts.

[0011] Further, the continuous phase emulsion is prepared by mixing the following raw materials in the following proportions by weight: styrene 5-20 parts, methyl methacrylate 10-30 parts, hydroxyethyl acrylate 5-25 parts, n-butyl acrylate 5-25 parts, acrylic acid 5-25 parts, polyurethane 5-20 parts, potassium persulfate 5-10 parts, sodium dodecyl sulfate 5-10 parts, and water 30-50 parts.

[0012] Further, the continuous phase emulsion is prepared by mixing the following raw materials in the following proportions by weight: styrene 5-20 parts, methyl methacrylate 10-30 parts, hydroxyethyl acrylate 5-25 parts, n-butyl acrylate 5-25 parts, acrylic acid 5-25 parts, polyurethane 5-20 parts, potassium persulfate 5-10 parts, sodium dodecyl sulfate 5-10 parts, and water 30-50 parts.

[0013] Further, the functional additives are prepared by mixing the following raw materials in the following proportions by weight: dispersant 5-20 parts, defoaming agent 5-15 parts, leveling agent 5-20 parts, adhesion agent 10-35 parts, and film-forming aid 5-20 parts.

[0014] Further, the functional additives are prepared by mixing the following raw materials in the following proportions by weight: dispersant 5-20 parts, defoaming agent 5-15 parts, leveling agent 5-20 parts, adhesion agent 10-35 parts, and film-forming aid 5-20 parts.

[0015] Further, the dispersant is a polyurethane solution, the defoaming agent is a silicone-based defoaming agent, the leveling agent is a water-soluble silicate compound, the adhesion agent is a phosphate-based adhesion agent, and the film-forming aid is dipropyl alcohol butyl ether.

[0016] Further, the dispersant is BYK-W974, the defoaming agent is DiGo Tego-Airex900, the leveling agent is DiGo Tego-Glide450, the adhesion agent is Lencolo-4051, and the film-forming aid is DOW-COASOL.

[0017] The second object of the present application is to provide a preparation method of the FRP bar and cement-based material interface reinforcing coating, which comprises mixing and stirring C-S-H nanocrystals, a continuous phase emulsion, water and functional additives at 25 DEG C, with a stirring speed of 200-400 rpm and a stirring time of 5-10 min.

[0018] Further limitation, the preparation method of the continuous phase emulsion comprises mixing and stirring styrene, methyl methacrylate, hydroxyethyl acrylate, n-butyl acrylate, acrylic acid, polyurethane, potassium persulfate, sodium dodecyl sulfate and water at 25 DEG C, with a stirring speed of 200-400 rpm and a stirring time of 5-10 min, then heating to 70 DEG C and keeping for 0.5 h, and then cooling to 25 DEG C, to obtain the continuous phase emulsion.

[0019] The third object of the present application is to provide an application of the FRP bar and cement-based material interface reinforcing coating, which is specifically used for preparing FRP bar cement concrete prefabricated components.

[0020] Further limitation, the preparation method of the FRP bar cement concrete prefabricated component comprises coating the interface reinforcing coating on the surface of the FRP bar, forming a film layer on the surface of the FRP bar by heating, then placing the FRP bar in a forming mold, pouring cement concrete, and then demolding and standard curing after the cement is hardened, to obtain the FRP bar cement concrete prefabricated component.

[0021] Further limitation, the temperature for forming the film layer of the interface reinforcing coating is 15 DEG C-35 DEG C, and the time is 3 min-60 min.

[0022] Compared with the prior art, the present application has the following advantages:

[0023] (1) The present application uses C-S-H nanocrystals as the raw material for preparing the FRP bar and cement-based material interface reinforcing coating, provides nucleation sites for the cement hydration products, reduces the nucleation potential barrier, promotes the generation of C-(A)-S-H gel, thereby reducing the interface porosity, reducing the interface defects, and physically connecting the FRP bar and the cement matrix through the C-(A)-S-H gel, to realize the integration of the FRP bar and the cement matrix.

[0024] (2) The continuous phase emulsion contained in the FRP bar and cement-based material interface reinforcing coating provided by the present application is water-based acrylic modified polyurethane, wherein styrene, methyl methacrylate and n-butyl acrylate are used as shell monomers, hydroxyethyl acrylate is used as a soft monomer, and acrylic acid is used as an acid monomer, so that the coating has excellent wear resistance, toughness, water resistance, stability and other comprehensive properties.

[0025] (3) The FRP bar provided by the application replaces the surface treatment of the FRP bar such as weaving, sand blasting, groove cutting and ribbing, and solves the problems of large equipment investment and high production cost. DETAILED DESCRIPTION

[0026] In order to make the above objectives, characteristics and advantages of the present application more apparent, specific embodiments of the present application are described in detail below with reference to the embodiments of the present application.

[0027] In the following description, a large number of specific details are set forth in order to facilitate a thorough understanding of the present application, but the present application can also be implemented in other manners different from those described herein, and those skilled in the art can make similar generalizations without departing from the concept of the present application, so the present application is not limited to the specific embodiments disclosed below.

[0028] Secondly, the "one embodiment" or "embodiment" referred to herein means that a specific feature, structure or characteristic can be included in at least one implementation of the present application. "In one embodiment" appearing in different places in the specification does not mean the same embodiment, nor is it an embodiment that is separate or alternative to other embodiments.

[0029] The experimental methods used in the following embodiments are conventional methods unless otherwise specified. The materials, reagents, methods and instruments used are conventional materials, reagents, methods and instruments in the art unless otherwise specified, and can be obtained by commercial channels by those skilled in the art.

[0030] The dispersing agent used in the following embodiments is BYK-W974 wetting dispersing agent from BYK Chemical, the defoaming agent is Tego-Airex900 from Degussa, the leveling agent is Tego-Glide450 from Degussa, the adhesion agent is Lencolo-4051 from Bluecoat, and the film-forming aid is DOW-COASOL from Dow.

[0031] Embodiment 1

[0032] First step, preparation of continuous phase emulsion:

[0033] Take 10 parts of styrene, 25 parts of methyl methacrylate, 5 parts of hydroxyethyl acrylate, 10 parts of n-butyl acrylate, 5 parts of acrylic acid, 20 parts of polyurethane, 5 parts of potassium persulfate, 7 parts of sodium dodecyl sulfate and 50 parts of water, mix and stir uniformly at 25℃, the stirring speed is 300rpm, the stirring time is 10min, then heat to 70℃ and keep for 0.5h, then cool to 25℃, to obtain the continuous phase emulsion.

[0034] Second step, preparation of interface reinforcing coating:

[0035] The C-S-H nanocrystals 70 parts, continuous phase emulsion 45 parts, water 15 parts and functional additives 10 parts are mixed at 25℃, the stirring speed is 200 rpm, and the stirring time is 8 min, to obtain the interface enhanced coating.

[0036] The C-S-H nanocrystals include 20 parts of nano-SiO2, 20 parts of nano-CaCO3 and 10 parts of nano-hydrated calcium silicate (C-S-H), and the specific hydrated calcium silicate (C-S-H) is purchased from BASF Company, model X-SEED. The functional additives include 15 parts of dispersant, 5 parts of defoaming agent, 10 parts of leveling agent, 10 parts of adhesion agent and 20 parts of film-forming aid.

[0037] Step 3: Production of cement concrete prefabricated component:

[0038] The interface enhanced coating is coated on the surface of the smooth round FRP bar, and the temperature is raised to 25℃, and the film is formed after 35 min of heat preservation.

[0039] The FRP bar is placed in the forming mold according to the design, and the cement concrete is poured, and after the cement is coagulated and hardened, the mold is removed and standard curing is performed, and the FRP bar cement concrete prefabricated component is formed.

[0040] According to the standard ACI440.3R, the interface bonding strength of the FRP bar coated with the interface enhanced coating and the cement concrete is 23.62 MPa.

[0041] Comparative Example 1

[0042] The difference between the present comparative example and Example 1 is that the interface enhanced coating is not coated on the surface of the smooth round FRP bar, and the operation process and parameter setting are the same as those of Example 1. The specific preparation process is as follows:

[0043] The smooth round FRP bar is placed in the forming mold according to the design, and the cement concrete is poured, and after the cement is coagulated and hardened, the mold is removed and standard curing is performed, and the FRP bar cement concrete prefabricated component is formed.

[0044] According to the standard ACI440.3R, the interface bonding strength of the FRP bar coated with the interface enhanced coating and the cement concrete is 23.62 MPa.

[0045] According to the interface bonding strength measured in Comparative Example 1 and Comparative Example 1, the interface enhanced coating of the FRP bar and the cement-based material provided by the present application can greatly improve the interface bonding strength.

[0046] Although the present application has been disclosed with the preferred embodiments as above, it is not intended to limit the present application, and any person skilled in the art can make various modifications and modifications without departing from the spirit and scope of the present application, therefore the protection scope of the present application should be defined by the claims.

Claims

1. An FRP bar and cementitious material interface enhancement coating, characterized by, The interface reinforcing coating is prepared from the following raw materials in parts by weight: C-S-H nanocrystals 20-80 parts, continuous phase emulsion 35-55 parts, water 10-20 parts, and functional additives 10-15 parts. The C-S-H nanocrystals are one or more of nano-SiO2, nano-CaCO3, nano-TiO2, carbon nanotubes, and nano-hydrated calcium silicate. The continuous phase emulsion includes, in parts by mass: styrene 5-20 parts, methyl methacrylate 10-30 parts, hydroxyethyl acrylate 5-25 parts, n-butyl acrylate 5-25 parts, acrylic acid 5-25 parts, polyurethane 5-20 parts, potassium persulfate 5-10 parts, sodium dodecyl sulfate 5-10 parts, and water 30-50 parts.

2. The FRP bar-cement-based material interface enhancement coating according to claim 1, wherein The functional additives include, in parts by mass: dispersant 5-20 parts, defoamer 5-15 parts, leveling agent 5-20 parts, adhesion agent 10-35 parts, and film-forming aid 5-20 parts.

3. The FRP bar-cement-based material interface enhancement coating according to claim 2, wherein The dispersant is a polyurethane solution, the defoamer is an organic silicon defoamer, the leveling agent is a water-soluble silicate compound, the adhesion agent is a phosphate ester adhesion agent, and the film-forming aid is dipropyl alcohol butyl ether.

4. The FRP bar-cement-based material interface enhancement coating according to claim 2 or 3, characterized in that, The dispersant is BYK-W974, the defoamer is Digo Tego-Airex900, the leveling agent is Digo Tego-Glide450, and the adhesion agent is Lenco Lencolo-4051.

5. A method of preparing the interfacial reinforcement coating of claim 1, characterized by, The C-S-H nanocrystals, the continuous phase emulsion, the water, and the functional additives are mixed and stirred at 25°C, at a stirring speed of 200-400 rpm for 5-10 min.

6. Use of a continuous phase emulsion for the preparation of an interfacially enhanced coating according to claim 1, characterized in that, The preparation method of the continuous phase emulsion includes the following steps: mixing and stirring styrene, methyl methacrylate, hydroxyethyl acrylate, n-butyl acrylate, acrylic acid, polyurethane, potassium persulfate, sodium dodecyl sulfate, and water at 25°C, at a stirring speed of 200-400 rpm for 5-10 min, then heating to 70°C and keeping for 0.5 h, and then naturally cooling to 25°C to obtain the continuous phase emulsion.

7. Use of the interface-enhancing coating according to claim 1, characterized in that The interface reinforcing coating is prepared from the following raw materials in parts by weight: C-S-H nanocrystals 20-80 parts, continuous phase emulsion 35-55 parts, water 10-20 parts, and functional additives 10-15 parts.

8. A method of manufacturing a FRP bar cement concrete precast member, characterized by, The interface reinforcing coating is prepared from the following raw materials in parts by weight: C-S-H nanocrystals 20-80 parts, continuous phase emulsion 35-55 parts, water 10-20 parts, and functional additives 10-15 parts. The interface reinforcing coating is prepared from the following raw materials in parts by weight: C-S-H nanocrystals 20-80 parts, continuous phase emulsion 35-55 parts, water 10-20 parts, and functional additives 10-15 parts.