CN114580187B - Method for evaluating residual service life of epoxy adhesive for splicing prefabricated sections in service - Google Patents
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- 238000000034 method Methods 0.000 title claims abstract description 27
- 229920006332 epoxy adhesive Polymers 0.000 title claims abstract description 14
- 239000000853 adhesive Substances 0.000 claims abstract description 91
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- 238000006731 degradation reaction Methods 0.000 claims abstract description 34
- 238000012669 compression test Methods 0.000 claims abstract description 29
- 239000000243 solution Substances 0.000 claims abstract description 23
- 238000010998 test method Methods 0.000 claims abstract description 20
- 239000003513 alkali Substances 0.000 claims abstract description 13
- 230000001808 coupling effect Effects 0.000 claims abstract description 13
- 238000010257 thawing Methods 0.000 claims abstract description 13
- 239000002253 acid Substances 0.000 claims abstract description 10
- 238000011156 evaluation Methods 0.000 claims abstract description 10
- 239000012266 salt solution Substances 0.000 claims abstract description 9
- 238000011160 research Methods 0.000 claims abstract description 5
- 230000000052 comparative effect Effects 0.000 claims abstract description 4
- 230000007246 mechanism Effects 0.000 claims abstract description 4
- 238000012360 testing method Methods 0.000 claims description 26
- 238000005070 sampling Methods 0.000 claims description 23
- 230000006835 compression Effects 0.000 claims description 19
- 238000007906 compression Methods 0.000 claims description 19
- 239000003292 glue Substances 0.000 claims description 16
- 238000013461 design Methods 0.000 claims description 11
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 10
- 230000008859 change Effects 0.000 claims description 9
- 238000007789 sealing Methods 0.000 claims description 8
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- 230000005855 radiation Effects 0.000 claims description 3
- 238000010125 resin casting Methods 0.000 claims description 3
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 claims 2
- 239000011780 sodium chloride Substances 0.000 claims 1
- 239000000463 material Substances 0.000 description 11
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- 238000006467 substitution reaction Methods 0.000 description 1
- 230000009974 thixotropic effect Effects 0.000 description 1
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Abstract
The invention relates to a method for evaluating the residual service life of an epoxy adhesive for splicing prefabricated sections in service, belonging to the technical field of epoxy adhesives for constructional engineering. According to the method, 6 ageing treatment modes of damp heat, freeze thawing circulation, ultraviolet light, acid solution, alkali solution and salt solution are adopted in a laboratory by referring to an ageing test method in the existing relevant standard and specification, and the epoxy adhesive for assembling the prefabricated sections of 2 types, namely a sample compression test piece of the splice adhesive is subjected to artificial accelerated ageing; the physical and mechanical properties of the samples treated under the 6 aging conditions are analyzed and compared to obtain a relation curve of the physical and mechanical properties of the splice adhesive under different aging conditions along with aging time and an influence rule; and (3) obtaining a fitting curve and a mathematical formula of relative compressive strength along with aging time under the multi-factor coupling effect through comparative research, so as to establish an evaluation method of the residual life of the mechanical property of the splice adhesive and estimate the mechanism of performance degradation of the splice adhesive in a typical service environment.
Description
Technical Field
The invention relates to a method for evaluating the residual service life of an epoxy adhesive for splicing prefabricated sections in service, belonging to the technical field of epoxy adhesives for constructional engineering.
Background
The epoxy adhesive (hereinafter referred to as splice adhesive) for splicing the prefabricated segments is a key adhesive material in the splicing engineering of the prefabricated segments, has the characteristics of high early compressive strength, high compression elastic modulus, high compression shear strength, good thixotropic property and the like, and mainly plays roles of lubrication, anchor bolts, water resistance, rapid splicing and the like. The joint is a key stress part of the whole prefabricated component in the prefabricated segment assembly engineering, and is the weakest link, and the performance of the splicing adhesive serving as a joint material directly influences the service life of the component. In the actual service process, the mechanical properties of the splice adhesive are continuously deteriorated after the splice adhesive is comprehensively influenced by environmental factors such as humidity, temperature, illumination and the like. According to the stress requirement in the actual working condition of the splicing adhesive, the compression strength and the bending strength can be used as main evaluation indexes of the integral mechanical property of the material. However, how to find a scientific and reasonable technical means to evaluate the residual life of the splice glue in the actual service process is still in need of solving.
The service life is presumed to be a common means of the existing high polymer material service life assessment method through the mathematical fitting relation between a certain key property of the material and the degradation factor, such as a high polymer material service life assessment method disclosed in CN 110501212A. However, the prior researches are limited to examining the degradation of a specific property of a material after the material is subjected to a single environment. In the actual use process, the construction working condition of the splicing glue is complex, the splicing glue is subjected to the comprehensive action of various adverse factors, and the service life of the splicing glue is estimated to be greatly different from the actual condition of engineering application by only depending on the degradation condition under the action of a certain environment. Meanwhile, in the engineering application process of the material, people often pay attention to whether the material still meets the design requirement after the key mechanical property of the material is deteriorated, and if the material meets the use requirement, the remaining service life of the material is longer.
Disclosure of Invention
In order to solve the problems in the prior art, the invention provides a method for evaluating the residual service life of an epoxy adhesive for splicing prefabricated sections in service, which comprehensively inspects the performance degradation condition of the splicing adhesive under the combined action of multiple factors by simulating the action of a field environment in a laboratory, and obtains an attenuation function model by fitting the relation of the relative strength of the splicing adhesive after the coupling of the multiple factors along with the aging time under the same aging time, so that the durability of the splicing adhesive in practical engineering application is more accurately and comprehensively reflected.
In order to achieve the above purpose, the invention adopts the following technical scheme:
The method comprises the steps that 6 ageing treatment modes of damp heat, freeze thawing circulation, ultraviolet light, acid solution, alkali solution and salt solution are adopted in a laboratory, and the 2 types of epoxy adhesives for assembling prefabricated segments, namely sample compression test pieces of the splice adhesive, are subjected to manual accelerated ageing; the physical and mechanical properties of the samples treated under the 6 aging conditions are analyzed and compared to obtain a relation curve of the physical and mechanical properties of the splice adhesive under different aging conditions along with aging time and an influence rule; and (3) obtaining a fitting curve and a mathematical formula of relative compressive strength along with aging time under the multi-factor coupling effect through comparative research, so as to establish an evaluation method of the residual life of the mechanical property of the splice adhesive and estimate the mechanism of performance degradation of the splice adhesive in a typical service environment.
Further, the evaluation method specifically includes the steps of:
Step one: selecting a splice adhesive sample, manufacturing a compression test piece, performing compression test after an aging test, collecting to obtain the change condition of the compression strength of 2 different splice adhesives after being subjected to 6 different factors in a laboratory and accelerated aging action along with the degradation time, and obtaining the change trend curves of the compression strength of 2 varieties of splice adhesives along with the time under 6 aging conditions;
Step two: comprehensively analyzing the variation trend curves of the compressive strength with time under the 6 aging conditions obtained in the first step to obtain a degradation fitting curve of the relative strength of the splicing adhesive with the aging time under the same time and a mathematical expression thereof during multi-factor coupling, wherein the specific steps are as follows:
2.1 Respectively averaging the compressive strength values in 6 change trend curves of the splicing adhesive of 2 varieties under the same aging time to obtain a degradation curve of the compressive strength along with the multi-factor coupling effect;
2.2 Dividing the compressive strength value of the ordinate corresponding to each time point in the degradation curve of the compressive strength along with the multi-factor coupling effect by an initial value, namely converting the ordinate into relative strength, converting the value corresponding to the standard state 0 point into 1, so as to obtain the degradation curve of the relative compressive strength along with time under the multi-factor coupling effect, and fitting according to a first-order exponential decay function;
2.3 Fitting a degradation curve of 2.3) according to a first-order exponential decay function y=a1X exp (-X/t 1) +y0), resulting in a correlation coefficient as follows:
Y0：0.74555±0.00462；
A1：0.25066±0.00694；
t1：1416.23185±92.80969；
R square: 0.99542;
Finally, a mathematical expression of a relative strength degradation curve of the splice adhesive is obtained, as shown in a formula 1:
Y＝0.25066*exp(-T/1416.23185)+0.74555 (1)
Wherein Y-relative compressive strength; t-aging time;
Step three: and (2) in combination with the above-mentioned indication (1) in the second step, evaluating the durability of the adhesive body under the actual working condition, wherein the evaluation method is as follows:
3.1 Obtaining a core sample of splicing glue from a typical part of actual engineering application, and processing and forming the core sample into a compression test piece in a laboratory;
3.2 The compression test piece is tested according to the requirements of GB/T2567-2008 to obtain compressive strength P T1, which represents the compressive strength after T1 time is used in actual engineering;
3.3 Checking the project rechecking report to obtain the compressive strength P T0 in the splicing glue state;
3.4 Y T1 is obtained by the ratio of P T0 to P T1, representing the relative compressive strength after t1 time is used in the actual engineering;
3.5 Substituting Y=Y T1 into the public expression (1), solving an equation to obtain T=T1, wherein T1 represents the time of the relative compressive strength corresponding to the artificial accelerated aging environment after T1 time is applied in the actual engineering;
3.6 Calculating a design limit value of Y T2,YT2 representing the relative compressive strength of the splicing adhesive according to the design requirement;
3.7 Substituting y=y T2 into formula 1 again, solving the equation to obtain t=t2; t2 represents the artificial accelerated aging time on the degradation curve corresponding to the design limit value of the relative compressive strength;
3.8 Setting the time of natural aging to a limit value as T2, t2=t2× (T1/T1);
3.9 The residual service time of the splicing adhesive reaching a limit value under the actual engineering is t3, and t3=t2-t 1. The first step specifically comprises the following steps:
1.1 Selecting a splice adhesive sample
Two varieties of splicing glue samples are selected and marked as No. 1 and No. 2 respectively;
1.2 Manufacturing a compression test piece
The compression test piece of the sample is a cylindrical compression test piece with the diameter of 10mm and the height of 25 mm; performing standard curing for 7d, and performing heat treatment at 60 ℃ for 24h;
1.3 Performing an aging test on the adhesive compression test piece sample cured in the standard state
Freeze thawing cycle test method: taking out the adhesive sample cured under the standard condition, placing the adhesive sample in a freeze-thawing circulation box after marking, and automatically performing freeze-thawing circulation under program control, wherein the conditions are that the temperature is 20 ℃ for 4 hours, the temperature is minus 20 ℃ for 4 hours, the actual time is 11 hours, the period is 1, and the sampling period is 50 times, 100 times, 200 times, 400 times and 600 times;
The wet heat aging treatment test method comprises the following steps: the temperature is 50 ℃ and the humidity is 98% RH; taking out the adhesive sample cured under the standard condition, marking, placing in a damp-heat aging box, and taking out the sample to test the physical and mechanical properties and structural properties, wherein the sampling period is 500h, 1000h, 1500h, 3000h and 4000h;
Acid solution treatment test method: taking out the adhesive sample cured under standard conditions, marking, completely immersing the adhesive sample in an acid solution container, sealing, and placing the container in a constant-temperature water bath kettle at 50 ℃ for sampling periods of 500h, 1000h, 1500h, 3000h and 4000h;
The alkali solution treatment test method comprises the following steps: the alkali solution is a saturated solution of Ca (OH) 2, and the pH value is (13.2+/-0.2); taking out the adhesive sample cured under the standard condition, making a mark, completely immersing the adhesive sample into a container of alkali solution, sealing, and placing the container in a constant-temperature water bath kettle at 50 ℃ for sampling with the sampling period of 500h, 1000h, 1500h, 3000h and 4000h;
Salt medium treatment test method: taking out the adhesive sample cured under standard conditions, marking, completely immersing in a container of the salt solution, sealing, and placing in a constant-temperature water bath kettle at 50 ℃ for sampling with sampling period of 500h, 1000h, 1500h, 3000h and 4000h;
The ultraviolet aging test method comprises the following steps: with reference to ASTM G154 test standard, using a straight lamp tube with a wavelength of UVA-340nm, irradiance of 0.89W/m 2, and an experimental cycle of 8 hours each, including ultraviolet radiation, wherein the blackboard temperature is 60 (+ -3) DEG C, then following 4 hours at 50 (+ -3) DEG C; taking out the adhesive sample cured under the standard condition, marking, and placing in a fluorescent ultraviolet box, wherein the sampling period is 500h, 1000h, 1500h, 3000h and 4000h;
1.4 Test of compressed test pieces
The test of the compression sample is carried out according to the method specified in 5.2 of the method for testing the performance of a resin casting body in GB/T2567-2008; the sample is broken at the speed of 2mm/min, a plurality of compression samples under each aging condition of each splicing glue sample of each model are grouped, 5 compression samples are tested in each group, and the average value of the compression strength at the maximum breaking load is taken as the compression strength value of the group.
The invention has the beneficial effects that:
According to the method, the performance degradation condition of the splice adhesive under the combined action of multiple factors is comprehensively examined through a mode of simulating the on-site environment action in a laboratory, and the decay function model is obtained through fitting the relation of the relative strength of the coupled multiple factors along with the ageing time under the same ageing time, so that the durability of the splice adhesive in practical engineering application is more accurately and comprehensively reflected. And by combining the aging attenuation model with the design value required by the actual working condition, the residual service life of the splice adhesive in the service state can be obtained efficiently.
The invention can realize the prediction of the residual service life of the splicing adhesive in the service process, can be directly used for guiding the on-site rapid detection of the prefabricated segment adhesive splicing engineering, can greatly improve the subsequent maintenance and repair efficiency of the prefabricated segment adhesive splicing engineering, can save a great amount of cost, effectively ensure the life and property safety of people, and can further promote the popularization and application of the technology in the fields of bridges, wind power and the like in China, thereby having good social benefit and economic benefit.
Drawings
FIG. 1 is a graph of a splice gum versus compressive strength degradation curve fit;
FIG. 2 is a flow chart of the sample aging, data processing, and remaining life assessment method of the present invention.
Detailed Description
Embodiments of the present invention will be described in detail with reference to fig. 1-2.
The method comprises the steps that 6 ageing treatment modes of damp heat, freeze thawing circulation, ultraviolet light, acid solution, alkali solution and salt solution are adopted in a laboratory, and the 2 types of epoxy adhesives for assembling prefabricated segments, namely sample compression test pieces of the splice adhesive, are subjected to manual accelerated ageing; the physical and mechanical properties of the samples treated under the 6 aging conditions are analyzed and compared to obtain a relation curve of the physical and mechanical properties of the splice adhesive under different aging conditions along with aging time and an influence rule; and (3) obtaining a fitting curve and a mathematical formula of relative compressive strength along with aging time under the multi-factor coupling effect through comparative research, so as to establish an evaluation method of the residual life of the mechanical property of the splice adhesive and estimate the mechanism of performance degradation of the splice adhesive in a typical service environment.
As shown in fig. 2, the method specifically comprises the following steps:
Step one: selecting a splice adhesive sample, manufacturing a compression test piece, performing compression test after an aging test, collecting to obtain the change condition of the compression strength of 2 different splice adhesives after being subjected to 6 different factors in a laboratory and accelerated aging action along with the degradation time, and obtaining the change trend curves of the compression strength of 2 varieties of splice adhesives along with the time under 6 aging conditions; the method specifically comprises the following steps:
1.1 Selecting a splice adhesive sample
Two varieties of splicing glue samples are selected and marked as No. 1 and No. 2 respectively;
1.2 Manufacturing a compression test piece
The compression test piece of the sample is a cylindrical compression test piece with the diameter of 10mm and the height of 25 mm; performing standard curing for 7d, and performing heat treatment at 60 ℃ for 24h;
1.3 Performing an aging test on the adhesive compression test piece sample cured in the standard state
Freeze thawing cycle test method: taking out the adhesive sample cured under the standard condition, placing the adhesive sample in a freeze-thawing circulation box after marking, and automatically performing freeze-thawing circulation under program control, wherein the conditions are that the temperature is 20 ℃ for 4 hours, the temperature is minus 20 ℃ for 4 hours, the actual time is 11 hours, the period is 1, and the sampling period is 50 times, 100 times, 200 times, 400 times and 600 times;
The wet heat aging treatment test method comprises the following steps: the temperature is 50 ℃ and the humidity is 98% RH; taking out the adhesive sample cured under the standard condition, marking, placing in a damp-heat aging box, and taking out the sample to test the physical and mechanical properties and structural properties, wherein the sampling period is 500h, 1000h, 1500h, 3000h and 4000h;
Acid solution treatment test method: taking out the adhesive sample cured under standard conditions, marking, completely immersing the adhesive sample in an acid solution container, sealing, and placing the container in a constant-temperature water bath kettle at 50 ℃ for sampling periods of 500h, 1000h, 1500h, 3000h and 4000h;
The alkali solution treatment test method comprises the following steps: the alkali solution is a saturated solution of Ca (OH) 2, and the pH value is (13.2+/-0.2); taking out the adhesive sample cured under the standard condition, making a mark, completely immersing the adhesive sample into a container of alkali solution, sealing, and placing the container in a constant-temperature water bath kettle at 50 ℃ for sampling with the sampling period of 500h, 1000h, 1500h, 3000h and 4000h;
Salt medium treatment test method: taking out the adhesive sample cured under standard conditions, marking, completely immersing in a container of the salt solution, sealing, and placing in a constant-temperature water bath kettle at 50 ℃ for sampling with sampling period of 500h, 1000h, 1500h, 3000h and 4000h;
The ultraviolet aging test method comprises the following steps: with reference to ASTM G154 test standard, using a straight lamp tube with a wavelength of UVA-340nm, irradiance of 0.89W/m 2, and an experimental cycle of 8 hours each, including ultraviolet radiation, wherein the blackboard temperature is 60 (+ -3) DEG C, then following 4 hours at 50 (+ -3) DEG C; taking out the adhesive sample cured under the standard condition, marking, and placing in a fluorescent ultraviolet box, wherein the sampling period is 500h, 1000h, 1500h, 3000h and 4000h;
1.4 Test of compressed test pieces
Testing the compression test sample according to the method specified in 5.2 of the method for testing the performance of a resin casting body in GB/T2567-2008, and testing the compression strength of the test sample; the sample is broken at the speed of 2mm/min, a plurality of compression samples under each aging condition of each splicing glue sample of each model are grouped, 5 compression samples are tested in each group, and the average value of the compression strength at the maximum breaking load is taken as the compression strength value of the group.
Step two: comprehensively analyzing the variation trend curves of the compressive strength with time under the 6 aging conditions obtained in the first step to obtain a degradation fitting curve of the relative strength of the splicing adhesive with the aging time under the same time and a mathematical expression thereof during multi-factor coupling, wherein the specific steps are as follows:
2.1 Respectively averaging the compressive strength values in 6 change trend curves of the splicing adhesive of 2 varieties under the same aging time to obtain a degradation curve of the compressive strength along with the multi-factor coupling effect;
2.2 Dividing the compressive strength value of the ordinate corresponding to each time point in the degradation curve of the compressive strength along with the multi-factor coupling effect by an initial value, namely converting the ordinate into relative strength, converting the value corresponding to the standard state 0 point into 1, so as to obtain the degradation curve of the relative compressive strength along with time under the multi-factor coupling effect, and fitting according to a first-order exponential decay function;
2.3 Fitting a degradation curve of 2.3) according to a first-order exponential decay function y=a1X exp (-X/t 1) +y0), as shown in fig. 1, yields the following correlation coefficients:
Y0：0.74555±0.00462；
A1：0.25066±0.00694；
t1：1416.23185±92.80969；
R square: 0.99542;
Finally, a mathematical expression of a relative strength degradation curve of the splice adhesive is obtained, as shown in a formula 1:
Y＝0.25066*exp(-T/1416.23185)+0.74555 (1)
Wherein Y-relative compressive strength; t-aging time;
Step three: and (2) in combination with the above-mentioned indication (1) in the second step, evaluating the durability of the adhesive body under the actual working condition, wherein the evaluation method is as follows:
3.1 Obtaining a core sample of splicing glue from a typical part of actual engineering application, and processing and forming the core sample into a compression test piece in a laboratory;
3.2 The compression test piece is tested according to the requirements of GB/T2567-2008 to obtain compressive strength P T1, which represents the compressive strength after T1 time is used in actual engineering;
3.3 Checking the project rechecking report to obtain the compressive strength P T0 in the splicing glue state;
3.4 Y T1 is obtained by the ratio of P T0 to P T1, representing the relative compressive strength after t1 time is used in the actual engineering;
3.5 Substituting Y=Y T1 into the public expression (1), solving an equation to obtain T=T1, wherein T1 represents the time of the relative compressive strength corresponding to the artificial accelerated aging environment after T1 time is applied in the actual engineering;
3.6 Calculating a design limit value of Y T2,YT2 representing the relative compressive strength of the splicing adhesive according to the design requirement;
3.7 Substituting y=y T2 into formula 1 again, solving the equation to obtain t=t2; t2 represents the artificial accelerated aging time on the degradation curve corresponding to the design limit value of the relative compressive strength;
3.8 Setting the time of natural aging to a limit value as T2, t2=t2× (T1/T1);
3.9 The residual service time of the splicing adhesive reaching a limit value under the actual engineering is t3, and t3=t2-t 1.
In view of the foregoing, it will be appreciated that in the embodiments of the invention described above, those skilled in the art will appreciate that the foregoing embodiments are illustrative and that the present invention is not to be construed as limited thereto, and that various changes, modifications, substitutions and alterations can be made without departing from the spirit and scope of the present invention.
Claims (2)
1. The method for evaluating the residual service life of the epoxy adhesive for splicing the prefabricated sections in service is characterized by comprising the following steps of: referring to the aging test method in the current relevant standard and specification, 6 aging treatment modes of damp heat, freeze thawing cycle, ultraviolet light, acid solution, alkali solution and salt solution are adopted in a laboratory, and the 2 types of epoxy adhesives for prefabricated segment assembly, namely sample compression test pieces of splicing adhesives are subjected to artificial accelerated aging; the physical and mechanical properties of the samples treated under the 6 aging conditions are analyzed and compared to obtain a relation curve of the physical and mechanical properties of the splice adhesive under different aging conditions along with aging time and an influence rule; the fitting curve and mathematical formula of the relative compressive strength along with the aging time under the multi-factor coupling effect are obtained through comparative research, so that an evaluation method of the residual life of the mechanical property of the splice adhesive is established, and the mechanism of performance degradation of the splice adhesive in a typical service environment is estimated;
the evaluation method specifically comprises the following steps:
Step one: selecting a splice adhesive sample, manufacturing a compression test piece, performing compression test after an aging test, collecting to obtain the change condition of the compression strength of 2 different splice adhesives after being subjected to 6 different factors in a laboratory and accelerated aging action along with the degradation time, and obtaining the change trend curves of the compression strength of 2 varieties of splice adhesives along with the time under 6 aging conditions;
Step two: comprehensively analyzing the variation trend curves of the compressive strength with time under the 6 aging conditions obtained in the first step to obtain a degradation fitting curve of the relative strength of the splicing adhesive with the aging time under the same time and a mathematical expression thereof during multi-factor coupling, wherein the specific steps are as follows:
2.1 Respectively averaging the compressive strength values in 6 change trend curves of the splicing adhesive of 2 varieties under the same aging time to obtain a degradation curve of the compressive strength along with the multi-factor coupling effect;
2.2 Dividing the compressive strength value of the ordinate corresponding to each time point in the degradation curve of the compressive strength along with the multi-factor coupling effect by an initial value, namely converting the ordinate into relative strength, converting the value corresponding to the standard state 0 point into 1, so as to obtain the degradation curve of the relative compressive strength along with time under the multi-factor coupling effect, and fitting according to a first-order exponential decay function;
2.3 Fitting a degradation curve of 2.2) according to a first-order exponential decay function y=a1 x exp (-T/T1) +y0), resulting in a correlation coefficient as follows:
Y0：0.74555 ± 0.00462；
A1：0.25066 ± 0.00694；
t1：1416.23185 ± 92.80969；
R square: 0.99542;
Finally, a mathematical expression of a relative strength degradation curve of the splice adhesive is obtained, as shown in a formula 1:
Y =0.25066*exp(-T/1416.23185) +0.74555（1）
Wherein Y-relative compressive strength; t-aging time;
step three: and (3) in combination with the formula (1) in the second step, evaluating the durability of the adhesive body under the actual working condition, wherein the evaluation method is as follows:
3.1 Obtaining a core sample of splicing glue from a typical part of actual engineering application, and processing and forming the core sample into a compression test piece in a laboratory;
3.2 The compression test piece is tested according to the requirements of GB/T2567-2008 to obtain compressive strength P T1, which represents the compressive strength after T1 time is used in actual engineering;
3.3 Checking the project rechecking report to obtain the compressive strength P T0 in the splicing glue state;
3.4 Y T1 is obtained by the ratio of P T0 to P T1, representing the relative compressive strength after t1 time is used in the actual engineering;
3.5 Substituting Y=Y T1 into the formula (1), and solving the formula to obtain T=T1, wherein T1 represents the time of the relative compressive strength corresponding to the artificial accelerated aging environment after T1 time is applied in the actual engineering;
3.6 Calculating a design limit value of Y T2,YT2 representing the relative compressive strength of the splicing adhesive according to the design requirement;
3.7 Substituting y=y T2 into formula 1 again, solving the equation to obtain t=t2; t2 represents the artificial accelerated aging time on the degradation curve corresponding to the design limit value of the relative compressive strength;
3.8 Setting the time of natural aging to a limit value as T2, t2=t2× (T1/T1);
3.9 The residual service time of the splicing adhesive reaching a limit value under the actual engineering is t3, and t3=t2-t 1.
2. The method for evaluating the residual service life of the epoxy adhesive for splicing in-service prefabricated segments according to claim 1, wherein the first step specifically comprises the following steps:
1.1 Selecting a splice adhesive sample
Two varieties of splicing glue samples are selected and marked as No. 1 and No. 2 respectively;
1.2 Manufacturing a compression test piece
The compression test piece of the sample is a cylindrical compression test piece with the diameter of 10mm and the height of 25 mm; performing standard curing for 7d, and performing heat treatment at 60 ℃ for 24h;
1.3 Performing an aging test on the adhesive compression test piece sample cured in the standard state
Freeze thawing cycle test method: taking out the adhesive sample cured under the standard condition, placing the adhesive sample in a freeze-thawing circulation box after marking, and automatically performing freeze-thawing circulation under program control, wherein the conditions are that the temperature is 20 ℃ for 4 hours, the temperature is minus 20 ℃ for 4 hours, the actual time is 11 hours, the period is 1, and the sampling period is 50 times, 100 times, 200 times, 400 times and 600 times;
the wet heat aging treatment test method comprises the following steps: the temperature is 50 ℃ and the humidity is 98% RH; taking out the adhesive sample cured under the standard condition, marking, placing in a damp-heat aging box, and taking out the sample to test the physical and mechanical properties and structural properties, wherein the sampling period is 500h, 1000h, 1500h, 3000h and 4000h;
Acid solution treatment test method: taking out the adhesive sample cured under standard conditions, marking, completely immersing the adhesive sample in an acid solution container, sealing, and placing the container in a constant-temperature water bath kettle at 50 ℃ for sampling periods of 500h, 1000h, 1500h, 3000h and 4000h;
The alkali solution treatment test method comprises the following steps: the alkali solution is saturated solution of Ca (OH) 2, and the pH value is 13.2+/-0.2; taking out the adhesive sample cured under the standard condition, making a mark, completely immersing the adhesive sample into a container of alkali solution, sealing, and placing the container in a constant-temperature water bath kettle at 50 ℃ for sampling with the sampling period of 500h, 1000h, 1500h, 3000h and 4000h;
Salt solution physical test method: the salt solution is saturated solution of NaCl, the adhesive sample which is cured under the standard condition is taken out, marked and then is completely immersed into a container of the salt solution, sealed and then placed into a constant-temperature water bath kettle at 50 ℃ with sampling period of 500h, 1000h, 1500h, 3000h and 4000h;
The ultraviolet aging test method comprises the following steps: referring to ASTM G154 test standard, using a straight lamp tube with a wavelength of UVA-340nm, irradiance of 0.89W/m 2, and an experimental cycle period of 8 hours each, including ultraviolet radiation, wherein the blackboard temperature is 60+ -3deg.C, and then the blackboard temperature is 50+ -3deg.C for 4 hours; taking out the adhesive sample cured under the standard condition, marking, and placing in a fluorescent ultraviolet box, wherein the sampling period is 500h, 1000h, 1500h, 3000h and 4000h;
1.4 Test of compressed test pieces
The test of the compressed samples is carried out according to the method specified by 5.2 in the method for testing the performance of a resin casting body in GB/T2567-2008, the compressed samples are loaded to the sample for damage at the speed of 2mm/min, a plurality of compressed samples under each aging condition of each splicing glue sample of each model are formed into a group, 5 compressed samples are tested in each group, and the average value of the compressive strength at the maximum damage load is taken as the compressive strength value of the group.
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