A method of treating a concrete structure joint seepage barrier

Abstract

The application discloses a treatment method of a concrete structure joint anti-seepage body, adopts a novel high polymer anti-seepage coating glass fiber mesh composite material, constructs an anti-seepage system on the surface of a concrete structure expansion joint, and improves the durability and anti-seepage property of the concrete structure. The application focuses on the change of the concrete structure expansion joint caused by the change of the ambient temperature, takes the temperature deformation as a core parameter, estimates the maximum opening of the concrete structure joint, establishes a method for calculating and checking the geometric size of the anti-seepage body on the surface of the expansion joint through stress balance conditions, and on the basis, proposes a concrete structure expansion joint treatment method based on the high polymer anti-seepage coating and the glass fiber mesh composite checking material and a construction scheme thereof, so as to prolong the service life of the concrete structure.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of concrete structure joint anti-seepage body processing method, belong to water conservancy and hydropower engineering technical field. BACKGROUND

[0002] In water conservancy project in China, leakage is one of common diseases.Leakage usually occurs at expansion joint, and the main reason is that the pre-set water stop is broken due to shrinkage of concrete structure, causing leakage problem of concrete structure, which can easily cause internal corrosion of concrete, corrosion of metal embedded parts, reduce the durability of concrete structure, and even affect the safe operation of water conservancy project.

[0003] Constructing waterproof coating on the surface of concrete structure expansion joint is one of the common methods to improve the anti-seepage performance of expansion joint and prolong the service life of concrete structure, such as using hand-scratching polyurea, epoxy glass fiber mesh composite material and the like.Different materials have their advantages and application scope, but also have their limitations, such as good extension performance of polyurea, which can adapt to temperature deformation of concrete, but its adhesion performance is poor and the requirement for concrete base surface is harsh, and when applied in engineering, problems such as delamination may occur, causing internal water seepage damage and the like, and the use effect is not good;and the toughness of the cured product of epoxy glass fiber mesh composite material is poor, and the anti-peeling and anti-cracking performance is low, and the laying of glass fiber mesh is mostly based on engineering experience, and how to judge the laying range of glass fiber mesh and the laying thickness of the used glass fiber mesh is still less researched.

[0004] In summary, it is necessary to propose a calculation method for the coverage range and thickness of anti-seepage body according to the stress characteristics of the surface anti-seepage body of concrete structure expansion joint, to propose an anti-seepage material with good adhesion performance and good ductility, which can adapt to temperature deformation of concrete expansion joint, to establish an expansion joint treatment method and construction scheme, and to provide a new solution and treatment basis for reducing or even avoiding water structure damage caused by expansion of expansion joint and further causing leakage problem of water conservancy concrete structure. SUMMARY

[0005] To solve the problems of the prior art, the present application provides a kind of concrete structure joint anti-seepage body processing method, which solves the problems that the anti-seepage body in the prior art does not simultaneously have good adhesion performance and good ductility, and expansion of expansion joint easily leads to water structure damage.

[0006] In order to achieve the above-mentioned target, the present application adopts the following technical scheme:

[0007] A kind of concrete structure joint anti-seepage body processing method, the specific steps are as follows:

[0008] Step one, collect the hydrological and meteorological data during construction and operation of concrete structure;

[0009] Step two, calculate the maximum opening of the concrete structure joint;

[0010] Step three, calculate and review the shear strength of the anti-seepage body and the concrete surface, and determine the minimum laying range of the anti-seepage body;

[0011] Step four, calculate and determine the minimum thickness of the glass fiber mesh reinforcement layer;

[0012] Step five, design and formulate the construction scheme of the anti-seepage body of the concrete structure joint.

[0013] Further, the aforementioned hydrological and meteorological data during the construction and operation of the concrete structure include the air temperature during the construction of the concrete structure and the water temperature during the operation.

[0014] Further, the aforementioned calculation method for determining the maximum opening of the concrete structure joint is:

[0015]

[0016] In the formula, δ is the structural deformation amount caused by temperature change, α is the linear expansion coefficient of the material, T 初 is the initial ambient temperature, T 低 is the minimum temperature, and L is the calculated length of the structure.

[0017] Further, the aforementioned step of calculating and reviewing the shear strength of the anti-seepage body and the concrete surface, and determining the minimum laying range of the anti-seepage body includes,

[0018] Calculate the shear stress between the anti-seepage body and the concrete:

[0019]

[0020] In the formula, G is the shear modulus of the anti-seepage body, τ is the shear strength between the anti-seepage body and the concrete, γ is the shear strain between the coating and the concrete, u is the horizontal displacement of the anti-seepage body, and v is the displacement of the anti-seepage body along the thickness direction.

[0021] Since the laying length and width of the anti-seepage body are much larger than the thickness of the anti-seepage body, the displacement v of the anti-seepage body along the thickness direction can be ignored, and the shear stress calculation is simplified as:

[0022]

[0023] The opening of the expansion joint is much smaller than the geometric size of the anti-seepage body and the elongation at the time of failure, so it is assumed that the shear stress at different parts of the anti-seepage body is the same, then:

[0024]

[0025] In the formula, h 防渗体 is the thickness of the anti-seepage body.

[0026] Calculate the amount of voids between the concrete and the impermeable body near the expansion joint:

[0027]

[0028] In the formula, ε 防渗体 The elongation of the impermeable body is its elongation.

[0029] Verify the shear strength of the impermeable body and the concrete surface: it must meet the following requirements. , where τ' is the tensile shear bond strength of the impermeable body;

[0030] Determine the minimum laying range of the impermeable body: the laying range of the impermeable body should be greater than the amount of voids.

[0031] Furthermore, the aforementioned steps for calculating and determining the minimum thickness of the glass fiber mesh reinforcement layer include:

[0032] Calculate the tensile force on the cross-section of the fiberglass mesh:

[0033]

[0034] In the formula, F is the tensile force borne by the cross-section of the fiberglass mesh. This refers to the shear stress on the surface of the fiberglass mesh.

[0035] Based on the force balance of the impermeable body, Since the tensile force is equal in magnitude and opposite in direction to τ, the tensile force on the cross section is:

[0036]

[0037] The tensile force on the cross section is calculated based on the normal stress of the cross section:

[0038]

[0039] In the formula, σ is the normal stress of the cross section of the glass fiber mesh;

[0040] Since the thickness of fiberglass mesh is generally less than 1 mm, the normal stress in the cross-section is the same along the thickness direction, and the calculation is simplified to: ,

[0041] In the formula, h 布 E represents the thickness of the glass fiber mesh reinforcement layer, and E represents the tensile modulus of elasticity of the glass fiber mesh.

[0042] Based on the above calculation formula, the thickness of the glass fiber mesh is:

[0043] .

[0044] Further, the aforementioned concrete structure joint anti-seepage body construction scheme comprises the following steps:

[0045] Base surface treatment: inspecting the concrete and structure joint, cleaning and polishing the concrete base surface, removing cement paste, rust and other sundries remaining on the concrete surface, chiseling and polishing the corners and concrete steps remaining in the structure joint, and ensuring that the concrete base surface is clean, flat and free of sharp foreign matters;

[0046] Bottom coating construction: ensuring that the coating is fully reacted and free of bubbles, and stirring for no less than 10 minutes, and evenly coating the base surface in two passes, with the wet film controlled at 110 µm~130 µm, and the dry film thickness controlled at 110 µm;

[0047] Middle coating construction: starting the middle coating construction 4 hours after the bottom coating construction, and coating in two to four passes to ensure the engineering quality, with the wet film controlled at 220 µm~280 µm, and the average dry film thickness controlled at 200 µm;

[0048] Glass fiber mesh reinforcement layer construction: after the first pass of middle coating is completed, the glass fiber mesh is pasted, a clean brush or roller is used to press the glass fiber mesh in one direction to ensure that the glass fiber mesh is fully and uniformly soaked, bubbles and voids in the glass fiber mesh are checked and repaired with a roller to ensure that the glass fiber mesh is firmly bonded with the middle coating, and then the remaining paint is sprayed, and a pass of middle coating is brushed on the edge joint of the glass fiber mesh after the middle coating is completed;

[0049] Top coating construction: after the middle coating is completed for 8 hours, the coating surface is surface-dried, and the bottom coating construction is started, and the top coating dry film thickness is 100 µm.

[0050] The present application has the following beneficial effects:

[0051] The high-molecular glass fiber mesh composite anti-seepage material has excellent adhesion and ductility. Through stress analysis of the anti-seepage body, the glass fiber mesh laying range and the thickness of the glass fiber mesh reinforcement layer are quantitatively calculated, and the concrete structure expansion joint and structure joint anti-seepage treatment method is established, thereby providing support for high-quality engineering construction. BRIEF DESCRIPTION OF DRAWINGS

[0052] Figure 1 is a design schematic diagram of the anti-seepage body of the concrete structure expansion joint of the present application;

[0053] Figure 2 is a measured water temperature of the in-service section of the present application;

[0054] Figure 3 is a stress analysis diagram of the glass fiber mesh of the present application;

[0055] Figure 4 is the processing flowchart of the present application. DETAILED DESCRIPTION

[0056] The present application is further described below in conjunction with the accompanying drawings. The following examples are only used to more clearly illustrate the technical solutions of the present application, and cannot be used to limit the protection scope of the present application.

[0057] The example takes a water conveying tunnel as an example, and the lining is a composite lining structure, one lining is a prefabricated reinforced concrete shield segment with a thickness of 0.3 m, and the second lining is cast-in-situ reinforced concrete with a thickness of 0.4 m, one expansion joint is arranged every 12 m, and the structure joint is designed as shown in Figure 1 The concrete of the second lining is poured by using ordinary commercial C35 concrete, the linear expansion coefficient is 1×10 -5 / ℃, and the linear expansion coefficient of the high polymer anti-seepage coating used in the example is 5.6×10 -5 / ℃.

[0058] The processing method of the concrete structure joint anti-seepage body disclosed by the present application quantifies the laying range and thickness of the concrete surface layer reinforcing material from the deformation amount of the concrete structure joint, and establishes a concrete structure joint anti-seepage body processing method in combination with the high polymer anti-seepage material, proposes an anti-seepage body construction scheme, and provides technical support for long-term operation safety of the project.

[0059] The processing method of the concrete structure joint anti-seepage body disclosed by the present application, as shown in Figure 4 , comprises the following steps:

[0060] Step 1, collect the concrete structure construction, hydrological and meteorological data during the operation period, including the air temperature during the construction period of the concrete structure and the water temperature during the operation period.

[0061] The example is located in Beijing, and the average monthly temperature data of Beijing in many years is investigated, and the Beijing meteorological characteristic values are shown in Table 1. The temperature in the tunnel before water conveying operation is designed to be 16℃.

[0062] Table 1 Average monthly temperature in Beijing in many years

[0063] Month January February March April May June July August September October November December Average temperature -1.5 1 9 16.5 22.5 26.5 28.5 27.5 22 14 5.5 -0.5 Daily mean minimum temperature -6 -4 3 10 16 21 24 23 17 9 1 -5 Daily mean maximum temperature 3 6 15 23 29 32 33 32 27 19 10 4

[0064] The water temperature data investigates the water temperature monitoring data of the tunnel in operation, as shown in Figure 2 , the average temperature in spring is 16℃, the highest temperature in summer is 30℃, the average temperature in autumn is 16℃, and the lowest temperature in winter is 3℃.

[0065] Step 2, calculate the maximum opening of the concrete structure joint; the deformation amount calculation formula of the concrete material and the anti-seepage coating under the condition of environmental temperature reduction is:

[0066]

[0067] where δ is the structural deformation caused by temperature change, α is the linear expansion coefficient of the material, T 初 is the initial ambient temperature, T 低 is the minimum temperature, and L is the calculated length of the structure.

[0068] In this embodiment, the concrete lining in the cavern has been completed before the construction of the impervious body. The maximum opening of the expansion joint is calculated based on the water temperature difference in the cavern during operation. The average temperature in autumn (16°C) is taken as T 初 , the minimum temperature in winter (3°C) is taken as T 低 , and the maximum shrinkage of the expansion joint is calculated to be 1.56 mm.

[0069] Step three, calculate and review the shear strength between the impervious body and the concrete surface, and determine the minimum laying range of the impervious body. When the structural joint reaches the maximum opening, the impervious body needs to be able to overcome the shear stress caused by the relative deformation between it and the concrete structural joint without being separated. The shear stress needs to satisfy:

[0070]

[0071] where G is the shear modulus of the impervious body, τ' is the tensile shear bond strength of the impervious body, τ is the shear strength between the impervious body and the concrete, γ is the shear strain between the coating and the concrete, u is the horizontal displacement of the impervious body, and v is the displacement of the impervious body along the thickness direction.

[0072] Since the laying length and width of the impervious body are much larger than its thickness, the displacement v of the impervious body along the thickness direction can be ignored, and the shear stress relationship is simplified as:

[0073]

[0074] The opening of the expansion joint is much smaller than the geometric size of the impervious body and its elongation at failure, so it is assumed that the shear stress is the same at different parts of the impervious body:

[0075]

[0076] h 防渗体 is the thickness of the impervious body;

[0077] Since the deformation of the expansion joint has a tensile effect on the impervious body, a certain void is generated between the concrete and the impervious body near the expansion joint to adapt to the deformation of the concrete, and the void volume is:

[0078]

[0079] where ε 防渗体 is the elongation of the impervious body. Therefore, the laying range of the impervious body should be greater than the void volume.

[0080] In the embodiment, the shear modulus of the high polymer anti-seepage body is 1.2 MPa, the tensile shear bonding strength of the anti-seepage body is 3 MPa when the environment reaches the minimum temperature, the thickness of the anti-seepage body is 1 mm, and the joint opening is 1.56 mm according to the calculation in step two. Therefore, the maximum shear stress that the anti-seepage body needs to withstand in the embodiment is 0.936 MPa, which is much lower than the tensile shear bonding strength of the coating. The void volume is 1.56 mm / 300% = 0.52 mm, so the laying width of the anti-seepage body on both sides of the expansion joint needs to be greater than 0.52 mm.

[0081] Step four, calculate the minimum thickness of the glass fiber mesh reinforcement layer; as shown in the formula, the thickness of the glass fiber mesh reinforcement layer is calculated through force balance. Figure 3

[0082] The tensile force on the cross section of the glass fiber mesh is:

[0083]

[0084] In the formula, F is the tensile force on the cross section of the glass fiber mesh, is the shear stress on the surface of the glass fiber mesh.

[0085] According to the force balance of the anti-seepage body, the shear stress on the surface of the glass fiber mesh is equal in size and opposite in direction to the shear stress calculated in step three, so the tensile force on the cross section is:

[0086]

[0087] In addition, the tensile force is calculated according to the normal stress on the cross section as:

[0088]

[0089] In the formula, σ is the normal stress on the cross section of the glass fiber mesh. Since the thickness of the glass fiber mesh is generally less than 1 mm, the normal stress on the cross section is the same along the thickness direction, and the calculation is simplified as

[0090] In the formula, h 布 is the thickness of the glass fiber mesh reinforcement layer, and E is the tensile elastic modulus of the glass fiber mesh.

[0091] Therefore, the thickness of the glass fiber mesh is:

[0092]

[0093] ​The mechanical properties of the glass fiber mesh cloth are excellent, and the tensile elastic modulus and tensile strength are high. The glass fiber mesh cloth is prepared in the embodiment: the tensile strength is 3650 MPa, the tensile elastic modulus is 2 GPa, and the minimum thickness of the glass fiber mesh cloth is 0.78 x 10 -5 m.

[0094] According to the calculation results of steps three and four, and the specifications of the glass fiber mesh cloth used in the market, the size of the reinforcing layer is determined as follows: 300 mm in width and 0.1 x 10 -4 mm.

[0095] Step five, design and formulate the construction scheme of the concrete structure joint anti-seepage body. The main scheme of the anti-seepage body construction is: base surface treatment → bottom coating construction → glass fiber mesh cloth pasting → middle coating construction → surface coating construction → acceptance and maintenance.

[0096] Further, the detailed processes of each step are as follows:

[0097] (a) Base surface treatment: inspect the concrete and structure joint, clean and polish the concrete base surface, remove the cement paste, rust and other sundries remaining on the concrete surface, and chisel and polish the corners and concrete steps remaining in the structure joint, so as to ensure that the concrete base surface is clean, flat and free of sharp foreign matters.

[0098] (b) Bottom coating construction: ensure that the coating is fully reacted and free of bubbles, and the stirrer is stirred for no less than 10 minutes. The coating is evenly applied on the base surface in two passes, the wet film of each pass is controlled within 110 µm~130 µm, the interval between each process is 2~4 hours, and the dry film thickness is 100 µm.

[0099] (c) Middle coating construction: the middle coating construction is started 4 hours after the bottom coating construction. In order to ensure the engineering quality, the coating is applied in two to four passes, the wet film of each pass is controlled within 220 µm~280 µm, and the average dry film thickness of each pass is 200 µm.

[0100] (d) Glass fiber mesh cloth reinforcing layer construction: after the first pass of middle coating is completed, the glass fiber mesh cloth is pasted. A clean brush or roller is used to press the glass fiber mesh cloth in one direction, so that the glass fiber mesh cloth is completely and uniformly soaked. Check whether the glass fiber mesh cloth has bubbles, voids and other phenomena, and use a roller to repair. Then, the remaining paint is sprayed. After the middle coating is completed, a layer of middle coating is brushed on the edge joint of the glass fiber mesh cloth.

[0101] (e) Surface coating construction: the surface coating construction is started 8 hours after the middle coating is completed, and the dry thickness of the surface coating is 100 um.

[0102] The above merely describes the preferred embodiments of the present application, and it should be pointed out that, for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present application, and these improvements and modifications should also be considered as the protection scope of the present application.

Claims

1. A method of treating a concrete structure joint barrier, characterized by, The specific steps are as follows: Step one, collect the construction of concrete structure, hydrology, meteorological data during operation period; Step two, calculate the maximum opening of the concrete structure joint; Step three, calculate and review the shear strength of the anti-seepage body and the concrete surface, and calculate the minimum laying range of the anti-seepage body; Step four, calculate and determine the minimum thickness of the glass fiber mesh reinforcement layer; Step five, design and formulate the construction scheme of the concrete structure joint anti-seepage body; The step of calculating and reviewing the shear strength of the anti-seepage body and the concrete surface, and calculating the minimum laying range of the anti-seepage body comprises, Calculate the shear stress between the anti-seepage body and the concrete: ， In the formula, G is the shear modulus of the anti-seepage body, τ is the shear strength between the anti-seepage body and the concrete, γ is the shear strain between the coating and the concrete, u is the horizontal displacement of the anti-seepage body, and v is the displacement of the anti-seepage body along the thickness direction; Since the laying length and width of the anti-seepage body are much larger than the thickness of the anti-seepage body, the displacement v of the anti-seepage along the thickness direction is not considered, and the shear stress calculation is simplified as: ， The opening of the expansion joint is much smaller than the geometric size of the anti-seepage body and the elongation when it is damaged, so it is assumed that the shear stress of different parts of the anti-seepage body is the same, that is: ， where h 防渗体 is the thickness of the barrier, and δ is the amount of structural deformation due to temperature changes; Calculate the void volume of the concrete and the anti-seepage body near the expansion joint: ， In the formula, ε 防渗体 elongation of the barrier Review of the shear strength of the impermeable body to the concrete surface: must satisfy where τ' is the tensile shear bond strength of the impermeable body; Determine the minimum laying range of the anti-seepage body: the laying range of the anti-seepage body should be greater than the void volume.

2. The method of treating a concrete structure joint sealer according to claim 1, wherein The concrete structure construction, hydrology, and meteorological data during operation period include the air temperature during the construction period of the concrete structure and the water temperature during the operation period.

3. The method of treating a concrete structure joint sealer according to claim 1, wherein The calculation method for determining the maximum opening of the concrete structure joint is: ， where a is the linear expansion coefficient of the material, T 初 is the ambient temperature at the initial time, T 低 is the minimum temperature, L is the calculated length of the structure.

4. The method of treating a concrete structure joint sealer according to claim 3, wherein The step of calculating and determining the minimum thickness of the glass fiber mesh reinforcement layer comprises: Calculate the tension on the cross section of the glass fiber mesh: ， where F is the tensile force on the cross section of the glass fiber mesh, is the shear stress on the surface of the glass fiber mesh; According to the stress balance of the impermeable body, The tensile force on the cross section is equal to the size of τ and opposite in direction. ， According to the normal stress on the cross section, the tension on the cross section is calculated as: ， In the formula, σ is the normal stress on the cross section of the glass fiber mesh; Since the thickness of the glass fiber mesh cloth is generally less than 1 mm, the cross-sectional normal stress is the same along the thickness direction, and the calculation is simplified as follows: , wherein h 布 is the thickness of the glass fiber mesh reinforcement layer, and E is the tensile elastic modulus of the glass fiber mesh. According to the above calculation formula, the thickness of the glass fiber mesh is: 。 5. The method of treating a concrete structure joint sealer according to claim 1, wherein The construction scheme of the concrete structure joint anti-seepage body comprises the following steps: Base surface treatment: inspect the concrete and structure joint, clean and polish the concrete base surface, remove the cement paste and iron rust debris remaining on the concrete surface during construction, chisel and polish the corners and concrete steps remaining at the structure joint during construction, and ensure that the concrete base surface is clean, flat, and free of sharp foreign matter; Bottom coating construction: ensure that the coating is fully reacted and does not produce bubbles, the stirrer is stirred for not less than 10 minutes, and the coating is evenly coated on the base surface in two passes, with the wet film controlled at 110µm~130µm, and the dry film thickness is 110µm; Middle coating construction: start middle coating construction 4 hours after bottom coating construction, and coat in two to four passes to ensure engineering quality, with the wet film controlled at 220µm~280µm, and the average dry film thickness of each pass is 200µm; Glass fiber mesh reinforcement layer construction: After the first coat is sprayed, the glass fiber mesh is pasted. A clean brush or roller is used to press the glass fiber mesh in one direction, so that the glass fiber mesh is completely and uniformly saturated. Check if there are bubbles or voids in the glass fiber mesh. Use a roller to repair it, ensure that the glass fiber mesh is firmly bonded to the intermediate coating, and then spray the remaining paint. After the intermediate coating is completed, a layer of intermediate coating is brushed on the edge of the glass fiber mesh. Topcoat construction: After 8 hours of intermediate coating, the coating surface is dry to the touch. Start the primer construction. The topcoat dry film thickness is 100 µm.

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