CN114739826B - Analysis method for deformation and damage of bonding surface of concrete repair material - Google Patents

Analysis method for deformation and damage of bonding surface of concrete repair material Download PDF

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CN114739826B
CN114739826B CN202210247219.6A CN202210247219A CN114739826B CN 114739826 B CN114739826 B CN 114739826B CN 202210247219 A CN202210247219 A CN 202210247219A CN 114739826 B CN114739826 B CN 114739826B
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strain
bonding surface
repair material
adhesive
debonding
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CN114739826A (en
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范向前
陆俊
刘决丁
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Nanjing Hydraulic Research Institute of National Energy Administration Ministry of Transport Ministry of Water Resources
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Nanjing Hydraulic Research Institute of National Energy Administration Ministry of Transport Ministry of Water Resources
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
    • G01N3/20—Investigating strength properties of solid materials by application of mechanical stress by applying steady bending forces
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N19/00—Investigating materials by mechanical methods
    • G01N19/04—Measuring adhesive force between materials, e.g. of sealing tape, of coating
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T90/00—Enabling technologies or technologies with a potential or indirect contribution to GHG emissions mitigation

Abstract

The invention discloses an analysis method for deformation and damage of a bonding surface of a concrete repair material, which comprises a bonding surface strain calculation method and a bonding surface debonding analysis method. The method for calculating the strain of the bonding surface comprises a method for acquiring the strain field of the surface of the repairing material, a method for analyzing the shear deformation of the repairing material under the action of concrete strain and cracks and a method for expressing the strain field of the bonding surface. The bonding surface debonding analysis method comprises a bonding surface critical debonding strain calculation method and a bonding surface debonding length calculation method. The bonding surface debonding analysis method comprises the steps of establishing a bonding surface energy criterion, calculating critical debonding strain of the bonding surface and debonding length of the bonding surface under any strain. The invention can realize nondestructive measurement and analysis of the strain of the bonding surface of the concrete repair material, evaluation of the reliability of the bonding surface, prediction and control of the damage degree of the bonding surface, and has higher result precision.

Description

Analysis method for deformation and damage of bonding surface of concrete repair material
Technical Field
The invention relates to an analysis method for deformation and damage of a bonding surface of a concrete repair material, and belongs to the field of concrete.
Background
Concrete is the most widely used material in the civil engineering field, and concrete cracks pose a great hazard to the safety of the structure. Therefore, it is necessary to repair concrete with cracks using a repair material, such as filling epoxy resin at the cracks, sticking FRP cloth, or the like.
The interface strength and mechanical behavior of the repairing material and the concrete are directly related to the performance of the repaired concrete structure, and the repairing material has important significance for national security. However, the internal interfaces of the different materials are hidden and difficult to directly monitor by the existing methods. In particular, the strain field and debonding behavior of the contact surface of the repair material and concrete cannot be directly observed by using the prior art, such as strain gages, displacement meters, acoustic emissions, radars, CT, and the like. The main reason is that these techniques cannot provide accurate strain field information by themselves, nor can they measure without affecting the original interface characteristics. Therefore, the prior art cannot meet the performance study of the contact surface of the repairing material and the concrete.
Disclosure of Invention
The invention aims to: in order to overcome the defects in the prior art, the invention provides an analysis method for deformation and damage of the bonding surface of the concrete repair material, which is a more visual and accurate way, directly provides the deformation characteristics of different material contacts, and lays a foundation for further analyzing the mechanical behavior of the contact surface.
The technical scheme is as follows: in order to solve the technical problems, the analysis method for deformation and damage of the bonding surface of the concrete repair material comprises the following steps:
(1) Manufacturing a standard slotted three-point bending concrete beam, adhering epoxy resin to the crack tip along the length direction of a test piece, performing a three-point bending test, and recording an epoxy resin surface strain field image by using a digital image module;
(2) Fitting the surface strain expression epsilon through the strain field image f (x)；
(3) Obtaining the strain epsilon of the contact surface by a contact surface strain field inversion method s (x)；
(4) Establishing an energy expansion criterion;
(5) Establishing interface stress balance;
(6) Establishing an interface force-temperature stress-friction force relation, and solving the energy of each part, thereby obtaining the debonding strain and the sliding length caused by different strain values.
Preferably, in the step (2), the surface strain field of the repair material is obtained by a surface strain field monitoring technology, such as Digital Image Correlation (DIC); strain data at the desired location is then retrieved and a strain curve expression ε is fitted using relevant data processing software (e.g., origin, etc.) f (x)。
Preferably, the contact surface strain ε s (x) Obtained by the following steps: firstly, calculating the shearing deformation of the repairing material in the crack expanding process according to the physical properties of the repairing material; then, epsilon is calculated according to the shearing deformation of the repair material f (x) And epsilon s (x) Is a relationship of (2); finally, use is made of the known ε f (x) To invert epsilon s (x)。
Preferably, in the step (4), the energy criterion of the contact surface is
Figure BDA0003545518330000021
r s Is the thickness of the adhesive, b is the width of the adhesive and repair material,
Figure BDA0003545518330000022
is the normal stress of the adhesive, w u To a debonding length E s Is the elastic modulus of the adhesive, l is the length of the adhesive and repair material, +.>
Figure BDA0003545518330000023
Is the normal stress of the adhesive, wherein I 1 Is the axial strain energy of the debonded area of the bonded layer, I 2 Is the axial strain energy of the plastic deformation zone of the bonding layer, I 3 Shear strain energy of the debonded region of the bond layer, I 4 Is the shear strain energy of the plastic deformation zone of the bonding layer.
Preferably, in the step (5)
Figure BDA0003545518330000024
σ s (x) Is the normal stress and tau of the adhesive distributed in the adhesive direction s (x，r s ) The adhesive has a shear stress distributed in the thickness direction.
Preferably, in the step (6), the relationship between interfacial force and temperature stress is:
Figure BDA0003545518330000025
Figure BDA0003545518330000026
Figure BDA0003545518330000027
Figure BDA0003545518330000028
Figure BDA0003545518330000029
is the temperature induced optical fiber normal stress, +.>
Figure BDA00035455183300000210
Is the optical fiber normal stress and alpha caused by poisson effect f Is the thermal expansion coefficient alpha of the repair material m Is the thermal expansion coefficient of the concrete matrix, delta T is the temperature change rate and E s Is the elastic modulus of the adhesive layer, v s Poisson's ratio of the adhesive layer, R is the thickness of the outer edge of the adhesive layer, v f Poisson's ratio, E, of repair material m Is the elastic modulus of the adhesive layer.
Interface force-friction relationship:
Figure BDA0003545518330000031
Figure BDA0003545518330000032
/>
Figure BDA0003545518330000033
Figure BDA0003545518330000034
is the positive stress of the adhesive layer caused by Poisson's ratio, < ->
Figure BDA0003545518330000035
The positive stress distribution of the bond coat, epsilon, caused by poisson's ratio is the strain at the bond coat and concrete interface.
Interfacial force expression (debonding section):
Figure BDA0003545518330000036
Figure BDA0003545518330000037
interfacial force expression (yield segment):
Figure BDA0003545518330000038
Figure BDA0003545518330000039
Figure BDA00035455183300000310
Figure BDA00035455183300000311
wherein x is the coordinate axis length along the paste length, sigma s (w u ) Is the normal stress of the adhesive layer at the debonding position,
Figure BDA00035455183300000312
Is the strain of the adhesive layer when the adhesive layer yields, < >>
Figure BDA00035455183300000313
Is the shear stress of the adhesive layer when it yields. The interfacial force expression of the yield section and the interfacial force debonding section expression are mainly used for solving I 1 、I 2 、I 3 And I 4 A kind of electronic device.
Preferably, the energy balance equation in the step (6):
-ΔU t ＝b·Δx·G c or (b)
Figure BDA00035455183300000314
Wherein b is the width of the adhesive layer
According to the above formula, the Leblanc's equation is calculated:
Figure BDA0003545518330000041
wherein the rate of change of the energy of each branch is expressed as:
Figure BDA0003545518330000042
/>
Figure BDA0003545518330000043
Figure BDA0003545518330000044
Figure BDA0003545518330000045
thus, the slipping length caused by the debonding strain and different strain values can be obtained. Let w u When =0 and x=0, the obtained ε is the debonding strain; substituting the known epsilon, x=0, then w u The slip length for this strain value.
The beneficial effects are that:
1. the interface analysis method can accurately acquire the strain distribution of the contact surface, is more visual and accurate compared with the traditional method, and is suitable for the behavior analysis of the contact surface in a long distance.
2. The interface debonding behavior analysis method can accurately obtain the debonding length of the contact surface of the bonding material and the concrete. Compared with the traditional method, the method not only can obtain the initial strain of debonding, but also can obtain the specific debonding position, and is beneficial to improving the bonding strength of the interface.
Drawings
Fig. 1 is a schematic diagram of surface strain field acquisition, in fig. 1, (a) is surface strain field observation, (b) is strain field extraction, and (c) is fitting of a strain curve;
FIG. 2 is a schematic diagram of an interface force distribution;
FIG. 3 is a schematic diagram of stress balance of an adhesive layer.
Detailed Description
The invention will be further described with reference to the accompanying drawings.
An analysis method for deformation and destruction of a bonding surface of a concrete repair material comprises the following steps
(1) And manufacturing a standard slotted three-point bent concrete beam, and pasting epoxy resin on the crack tip along the length direction of the test piece, as shown in fig. 1 (a). Carrying out a three-point bending test on the unilateral incision beam, and recording an epoxy resin surface strain field image by using a digital image module, wherein the image is shown in fig. 1 (b);
(2) Fitting the surface strain expression epsilon through the strain field image f (x) As shown in fig. 1 (c);
the fitted expression in this example is
Figure BDA0003545518330000051
(3) The inversion method of the strain field of the contact surface comprises the following specific steps: calculating the relation between the surface strain field and the contact surface strain field according to the shear deformation of the adhesive layer, and then substituting the known surface strain field into the relation to obtain the contact surface strain field and the contact surface strain epsilon s (x) The method comprises the steps of carrying out a first treatment on the surface of the In this example, the relationship between the surface strain field and the contact surface strain field can be expressed as:
Figure BDA0003545518330000052
by combining
Figure BDA0003545518330000053
Substituted into the above expression, the expression of the reverse performance +.>
Figure BDA0003545518330000054
Figure BDA0003545518330000055
(4) Establishing an energy expansion criterion;
Figure BDA0003545518330000056
r s is the thickness of the adhesive, b is the width of the adhesive and repair material,
Figure BDA0003545518330000057
is the normal stress of the adhesive, w u To a debonding length E s Is the elastic modulus of the adhesive, l is the length of the adhesive and repair material, +.>
Figure BDA0003545518330000058
Is the normal stress of the adhesive, wherein I 1 Is the axial strain energy of the debonded area of the bonded layer, I 2 Is the axial strain energy of the plastic deformation zone of the bonding layer, I 3 Shear strain energy of the debonded region of the bond layer, I 4 Is the shear strain energy of the plastic deformation zone of the bonding layer.
(5) Establishing interface stress balance as shown in figure 3;
Figure BDA0003545518330000059
σ s (x) Is the normal stress and tau of the adhesive distributed in the adhesive direction s (x，r s ) Shear stress of the adhesive distributed in the thickness direction;
(6) Establishing interface force-temperature stress-friction force relation, and obtaining the energy of each part, wherein the numerical values of each part of the energy expansion criterion calculated in the embodiment are shown in table 1, thereby obtaining debonding strain and sliding caused by different strain valuesAnd (5) shifting the length. In this embodiment, x=0, let ε=0.02, 0.07, 0.11, 0.13, and 0.15 be substituted into Lagrangian equation to obtain the debonding length of the interface at each strain level; x=0, let w u =0, then the critical debonding strain can be derived. The partial calculations are shown in table 2:
TABLE 1 energy spread criterion values for various portions
Figure BDA0003545518330000061
TABLE 2 calculation of debonding value
Figure BDA0003545518330000062
/>
Figure BDA0003545518330000071
The foregoing is only a preferred embodiment of the invention, it being noted that: it will be apparent to those skilled in the art that various modifications and adaptations can be made without departing from the principles of the present invention, and such modifications and adaptations are intended to be comprehended within the scope of the invention.

Claims (7)

1. The analysis method for deformation and destruction of the bonding surface of the concrete repair material is characterized by comprising the following steps of:
(1) Manufacturing a standard slotted three-point bending concrete beam, adhering epoxy resin to the split tip along the length direction of a test piece, performing a three-point bending test, and recording an epoxy resin surface strain field image by using a digital image module;
(2) Fitting the surface strain expression epsilon through the strain field image f (x)；
(3) By a contact surface strain field inversion method, the contact surface strain epsilon is obtained s (x)；
(4) Establishing an energy expansion criterion;
(5) Establishing interface stress balance;
(6) And establishing an interface force-temperature stress-friction force relation, and solving the energy of each part, thereby obtaining the debonding strain and the sliding length caused by different strain values.
2. The method for analyzing deformation and destruction of a bonding surface of a concrete repair material according to claim 1, wherein: in the step (2), firstly, a surface strain field of the repairing material is obtained through a surface strain field monitoring technology; strain data at the desired location is then taken and a strain curve expression ε is fitted using relevant data processing software f (x)。
3. The method for analyzing deformation and destruction of a bonding surface of a concrete repair material according to claim 1, wherein: the contact surface strain epsilon s (x) Obtained by the following steps: firstly, calculating the shearing deformation of the repairing material in the crack expanding process according to the physical properties of the repairing material; then, epsilon is calculated according to the shearing deformation of the repair material f (x) And epsilon s (x) Is a relationship of (2); finally, use is made of the known ε f (x) To invert epsilon s (x)。
4. The method for analyzing deformation and destruction of a bonding surface of a concrete repair material according to claim 1, wherein: in the step (4), the energy expansion criterion of the contact surface is that
Figure FDA0004134920860000011
r s Is the thickness of the adhesive, b is the width of the adhesive and repair material,
Figure FDA0004134920860000012
is the normal stress of the adhesive, w u To a debonding length E s Is the elastic modulus of the adhesive, l is the length of the adhesive and repair material, +.>
Figure FDA0004134920860000013
Is the normal stress of the adhesive, G s For adhesive layer shear modulus, where I 1 Is the axial strain energy of the debonded area of the bonded layer, I 2 Is the axial strain energy of the plastic deformation zone of the bonding layer, I 3 Shear strain energy of the debonded region of the bond layer, I 4 Is the shear strain energy of the plastic deformation zone of the bonding layer.
5. The method for analyzing deformation and destruction of a bonding surface of a concrete repair material according to claim 4, wherein: in the step (5)
Figure FDA0004134920860000021
σ s (x) Is the normal stress and tau of the adhesive distributed in the adhesive direction s (x,r s ) The adhesive has a shear stress distributed in the thickness direction.
6. The method for analyzing deformation and destruction of a bonding surface of a concrete repair material according to claim 5, wherein: interface force-temperature stress relationship in step (6):
Figure FDA0004134920860000022
Figure FDA0004134920860000023
/>
Figure FDA0004134920860000024
Figure FDA0004134920860000025
Figure FDA0004134920860000026
is the temperature induced optical fiber normal stress, +.>
Figure FDA0004134920860000027
Is the optical fiber normal stress and alpha caused by poisson effect f Is the thermal expansion coefficient alpha of the repair material m Is the thermal expansion coefficient alpha of the concrete matrix s Is the thermal expansion coefficient of the adhesive material, deltaT is the temperature change rate, E s Is the elastic modulus of the adhesive layer, v s Poisson's ratio of the adhesive layer, R is the thickness of the outer edge of the adhesive layer, v f Poisson's ratio, E, of repair material m Is the elastic modulus of the adhesive layer, mu is the friction coefficient between the repair material and the matrix, v m Poisson's ratio, r, of the matrix f Is the thickness of the repair material;
Figure FDA0004134920860000028
Figure FDA0004134920860000029
Figure FDA00041349208600000210
Figure FDA00041349208600000211
Figure FDA00041349208600000212
Figure FDA00041349208600000213
is the positive stress of the adhesive layer caused by Poisson's ratio, < ->
Figure FDA00041349208600000214
Positive stress distribution of the adhesive layer caused by poisson ratio, epsilon being strain of the adhesive layer and concrete interface, f being a first poisson coefficient, g being a second poisson coefficient:
interfacial force expression of the debonding section:
Figure FDA0004134920860000031
Figure FDA0004134920860000032
yield segment interfacial force expression:
Figure FDA0004134920860000033
Figure FDA0004134920860000034
Figure FDA0004134920860000035
Figure FDA0004134920860000036
wherein x is the coordinate axis length along the paste length, sigma s (w u ) Is the normal stress of the adhesive layer at the debonding position,
Figure FDA0004134920860000037
Is the strain of the adhesive layer when the adhesive layer yields, < >>
Figure FDA0004134920860000038
Is the shear stress of the adhesive layer when it yields.
7. The method for analyzing deformation and destruction of a bonding surface of a concrete repair material according to claim 6, wherein: the energy balance equation in the step (6):
-ΔU t ＝b·Δx·G c or (b)
Figure FDA0004134920860000039
Wherein b is the width of the adhesive layer
According to the above formula, the Leblanc's equation is calculated:
Figure FDA00041349208600000310
wherein the rate of change of the energy of each branch is expressed as:
Figure FDA00041349208600000311
Figure FDA00041349208600000312
Figure FDA0004134920860000041
Figure FDA0004134920860000042
wherein, the slip length caused by the debonding strain and different strain values is obtained so far, let w u When =0 and x=0, the obtained ε is the debonding strain; substituting the known epsilon, x=0, then w u The slip length for this strain value.
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CN105403161B (en) * 2015-12-29 2018-01-02 哈尔滨工业大学深圳研究生院 A kind of method that concrete structure crack width is detected using fibre optical sensor
CN107703179A (en) * 2017-10-11 2018-02-16 黑龙江省科学院高技术研究院 A kind of method for testing fibre reinforced composites interfacial detachment temperature and slip temperature
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US11169082B2 (en) * 2019-08-02 2021-11-09 King Fahd University Of Petroleum And Minerals Universal debonding test apparatus for carbon fiber reinforced polymer-concrete system and method for sequential multi-testing
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US11280713B2 (en) * 2020-03-26 2022-03-22 Saudi Arabian Oil Company Testing cement shear bond strength at reservoir conditions
CN111474044B (en) * 2020-04-24 2021-03-19 南京航空航天大学 Prediction method of fatigue hysteresis loop of woven ceramic matrix composite material considering multistage fatigue damage

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