Stress-responsive luminescent organic gelation and stress detection method

Abstract

The application discloses a stress response type luminescent organic gelatin, which is composed of the following components in parts by weight: 100-150 parts of epoxy resin, 30-50 parts of curing agent, 10-30 parts of toughening agent, 1-5 parts of diluent, 1-3 parts of defoaming agent, 100-400 parts of filler, 10-30 parts of residual luminescent fluorescent powder, and 1-3% of fiber in mass percent; the gelatin material has the functions of stress self-detection and self-luminescence; when not subjected to stress, the material has the self-luminescence characteristic; when subjected to stress, the gelatin material exhibits obvious visible light emission; when continuously applied with stress, the luminescence can be sustained, and the luminescence intensity is in direct proportion to the stress; compared with the stress detection mode of the traditional stress sheet single point single piece, the stress detection result of the gelatin material is in the form of visible light and is displayed in real time, the information result collection is simple, the detection range is wide, the structure stress action point can be quickly identified, and the stress change and development can be recorded in real time.

Description

Technical Field

[0001] The invention belongs to the technical field of composite materials, and in particular relates to a stress-responsive luminescent organic gel and a stress detection method. Background Art

[0002] With the advancement of structural design and material processing capabilities, the structures of buildings, bridges, and other construction projects are becoming increasingly complex. This makes it difficult to detect the stresses within the structures. Furthermore, environments such as complex alternating loads, temperature fluctuations, or corrosion fatigue can also lead to uneven stress distribution within the structure, accelerating crack propagation and causing rapid structural failure and fracture. In severe cases, this can even cause collapse and large-scale casualties. Therefore, real-time monitoring and recording of structural stress changes and developments is crucial to the healthy service life of construction projects.

[0003] Currently, the main methods for detecting structural stress include electrical measurement, which converts structural strain signals into electrical signals, and optical grating methods, which convert stress and strain signals of the measured structure into optical signals using fiber grating elements (FBGs). For example, the electrical measurement method involves attaching a strain gauge to a location where stress is concentrated, allowing stress detection at a specific point in the structure. However, a strain gauge can only collect strain data from a single point at a time. When multiple locations on a structure need to be detected, the entire detection system becomes extremely complex. Furthermore, the quality of the strain gauge attachment significantly affects the test results. Therefore, the development of new and efficient stress detection methods is crucial. For example, patent CN 214150733U discloses a concrete stress detection device capable of detecting stress within concrete, saving manpower and resources. It is important to note that currently, commonly used stress detection components are separate from the structure being detected. When the structure is complex, effectively integrating the two becomes extremely difficult. Given the current challenges with structural stress detection, if the cementitious materials used in building structures inherently possess stress detection capabilities, real-time recording and rapid detection of structural stress would be facilitated.

[0004] In recent years, it has been found that some solid materials will emit obvious luminescence when subjected to external stress or crack, and this luminescence phenomenon shows great application prospects in structural stress detection and fatigue crack tracking. For example, patent CN114717004A discloses a fluorescent powder that can be used in a stress sensor. The fluorescent powder can emit linear spectrum under the action of mechanical external force, and the stress luminescence intensity has self-recovery. Although there are many studies on stress fluorescent powder at present, if the fluorescent powder is directly doped into conventional cement-based materials, the luminescence performance of the fluorescent powder will be damaged due to the influence of water environment and alkaline environment, and the force-induced luminescence cannot be realized. At the same time, if the fluorescent powder is unevenly distributed in the cement-based material, the use effect will also be affected. Therefore, how to prepare a cementitious material containing stress fluorescent powder so that the material can be applied to the building structure without damaging the original structure or the fluorescent powder, thereby realizing the detection and monitoring of stress by using visible light, has become a technical problem to be solved. SUMMARY

[0005] The present application aims to provide a stress-responsive luminescent organic cementitious material. In the manufacturing process, a residual luminescent force-induced fluorescent powder is introduced in a specific way. When the cementitious material is subjected to external stress, an optical signal is displayed, realizing the coexistence of functionality and aesthetics, and playing an important role in real-time recording and detection of building structure stress. Another object of the present application is to provide a building structure stress detection method, which can not only quickly identify the stress action point of the structure, but also record the stress changes and developments in real time.

[0006] To achieve the above-mentioned objects, the technical solutions are as follows:

[0007] The stress-responsive luminescent organic cementitious material comprises the following components in parts by weight:

[0008] epoxy resin 100-150 parts, curing agent 30-50 parts, toughening agent 10-30 parts, diluent 1-5 parts, defoaming agent 1-3 parts, filler 100-400 parts, residual luminescent force-induced fluorescent powder 10-30 parts, and 1%o-3%o fiber by mass percentage.

[0009] According to the above scheme, the epoxy resin is bisphenol A type epoxy resin.

[0010] According to the above scheme, the curing agent is one of aliphatic amine or aromatic amine.

[0011] According to the above scheme, the toughening agent is any one of acrylate or polyurethane.

[0012] According to the above scheme, the diluent is glycidyl ether.

[0013] According to the above scheme, the defoaming agent is any one of alcohol, fatty acid, fatty acid ester, amide, organosilicon or polyether modified polysiloxane.

[0014] According to the above scheme, the filler is any one or mixture of two of waste rubber particles, regenerated rubber particles and rubber powder.

[0015] According to the above scheme, the fiber is any one or mixture of polypropylene fiber, steel fiber and basalt fiber.

[0016] According to the above scheme, the afterglow force-induced fluorescent powder is any one or mixture of two of europium and dysprosium doped strontium aluminate fluorescent powder and over metal ion doped zinc sulfide fluorescent powder.

[0017] The preparation method of the stress-responsive light-emitting organic gel comprises the following steps:

[0018] (1) mixing and stirring the epoxy resin, curing agent, toughening agent, diluent and defoaming agent uniformly to obtain a resin;

[0019] (2) adding the afterglow force-induced fluorescent powder, filler and fiber, mixing uniformly, then pouring into a mold and oscillating flat; after curing and curing at room temperature, the stress-responsive light-emitting organic gel test block is obtained.

[0020] A building structure stress detection method comprises the following steps:

[0021] According to the above scheme, the epoxy resin is 100-150 parts by weight, the curing agent is 30-50 parts by weight, the toughening agent is 10-30 parts by weight, the diluent is 1-5 parts by weight, the defoaming agent is 1-3 parts by weight, the filler is 100-400 parts by weight, the afterglow force-induced fluorescent powder is 10-30 parts by weight, and the fiber is 1%o-3%o by mass percentage.

[0022] The mixed material is extruded into the building structure stress detection part, and is dried and cured at room temperature, and the stress change is judged by the light-emitting condition.

[0023] According to the above scheme, the building structure stress detection part includes building structure cracks, load cracks and deformation cracks.

[0024] According to the above scheme, the method further comprises testing the light-emitting intensity of the cured sample of the mixed material under different stress sizes, obtaining the simulation function relationship between the stress size and the light-emitting intensity, and calculating the stress size through the light-emitting intensity of the grouting material in the building structure stress detection part.

[0025] Compared with the prior art, the present application has the following advantages:

[0026] (1) The present application uses specific methods to introduce residual luminescence force-induced fluorescent powder into the process of making organic cementitious materials, so that the cementitious materials have stress self-detection and self-luminescence functions, good physical properties, and practical application conditions. When not subjected to stress, the materials have self-luminescence characteristics. When subjected to stress, the cementitious materials exhibit obvious visible light emission. When continuous stress is applied, the luminescence can be sustained, and the luminescence intensity is proportional to the size of the stress.

[0027] (2) Compared with the traditional stress sheet single-point single-piece stress detection method, the stress detection results of the cementitious materials are displayed in real time in the form of visible light, the information results are easy to collect, the detection range is wide, not only can the stress action point of the structure be quickly identified, but also the stress changes and developments can be recorded in real time, a large amount of manpower, material resources and financial resources can be saved, the engineering stress detection efficiency can be effectively improved, and the present application has high economic value and practical engineering significance. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 : Residual luminescence emission spectrum diagram of Example 2 and Example 5;

[0029] Figure 2 : Stress emission spectrum diagram of Example 2 and Example 5;

[0030] Figure 3 : Force-induced luminescence intensity and stress value relationship diagram of Example 2 and Example 5.

[0031] Figure 4 : Force-induced luminescence intensity and stress value function relationship fitting diagram of Example 6. DETAILED DESCRIPTION

[0032] The following examples further illustrate the technical solutions of the present application, but do not limit the scope of protection of the present application.

[0033] The specific embodiment provides a stress-responsive luminescent organic cement, which comprises the following components in parts by weight:

[0034] epoxy resin 100-150 parts, curing agent 30-50 parts, toughening agent 10-30 parts, diluent 1-5 parts, defoaming agent 1-3 parts, filler 100-400 parts, residual luminescence force-induced fluorescent powder 10-30 parts, and 1%o-3%o of fiber by mass percentage.

[0035] Specifically, the epoxy resin is bisphenol A type epoxy resin.

[0036] Specifically, the curing agent is one of aliphatic amine or aromatic amine.

[0037] Specifically, the toughening agent is any one of acrylate or polyurethane.

[0038] Specifically, the diluent is glycidyl ether.

[0039] Specifically, the defoaming agent is any one of alcohol, fatty acid, fatty acid ester, amide, organosilicon or polyether modified polysiloxane.

[0040] Specifically, the filler is any one or mixture of two of waste rubber particles, reclaimed rubber particles, rubber powder.

[0041] Specifically, the fiber is any one or any mixture of polypropylene fiber, steel fiber, basalt fiber.

[0042] Specifically, the afterglow force-induced fluorescent powder is one or mixture of two of europium and dysprosium doped strontium aluminate fluorescent powder, over metal ion doped zinc sulfide fluorescent powder.

[0043] The specific embodiment provides a preparation method of the stress-responsive luminescent organic gel, comprising the following steps:

[0044] (1) mixing and stirring the epoxy resin, curing agent, toughening agent, diluent and defoaming agent uniformly to obtain a resin;

[0045] (2) adding the afterglow force-induced fluorescent powder, filler and fiber, mixing uniformly, then pouring into a mold and oscillating flat; after curing and curing at room temperature, the stress-responsive luminescent organic gel test block is obtained.

[0046] The specific embodiment further provides a building structure stress detection method, comprising the following steps:

[0047] Mixing 100-150 parts of epoxy resin, 30-50 parts of curing agent, 10-30 parts of toughening agent, 1-5 parts of diluent, 1-3 parts of defoaming agent, 100-400 parts of filler and 10-30 parts of afterglow force-induced fluorescent powder; additionally adding 1-3%o of fiber by mass percentage.

[0048] Extruding the mixed material into the building structure stress detection part, drying and curing at room temperature, and judging the stress change by the luminescence.

[0049] According to the above scheme, the building structure stress detection part includes building structure cracks, load cracks and deformation cracks.

[0050] According to the above scheme, it further includes testing the luminescence intensity of the cured sample of the mixed material under different stress sizes, obtaining the simulation function relationship between the stress size and the luminescence intensity; and calculating the stress size by the luminescence intensity of the grouting material in the building structure stress detection part.

[0051] The materials used in the following examples are as follows:

[0052] The resin used is bisphenol A type 128 epoxy resin, transparent liquid, density: 1.16 (g / cm 3 ,25℃,,Epoxy equivalent weight:184-190(G / EQ,,Viscosity:12000-15000(C11,A1 25℃,.

[0053] The curing agent used is aliphatic amine curing agent 1X-B2, a light yellow to brown transparent liquid, with a density of 0.97~1.03 (g / cm 3 ,25℃,,Viscosity:<300(m1a.s,25℃,,Theoretical active hydrogen equivalent:65-70g / active H.

[0054] The toughening agent used is polyurethane elastic modifier Q1-124F, light-colored transparent liquid, viscosity: 75000-130000 (m1a.s, 25℃, density: 1.05-1.10 (g / cm 3 ,25℃,reaction equivalent: 400~450g / eq.

[0055] The diluent used is C12-14 glycidyl ether AGE, a colorless transparent liquid with a viscosity of 6-12 (m1a.s, 25°C, an epoxy value of 0.32-0.35eq / 100g, and an epoxy equivalent weight of 286-313g / eq.

[0056] The defoaming agent used was silicone-based, and the product was centrifuged at 3000 rpm for 15 minutes without stratification or precipitation.

[0057] The waste rubber powder used is 60-80 mesh, the particle size of the waste rubber particles is 1-3mm, the appearance is black, and the density is 1.5-1.8 (g / cm 3 ,25℃,.

[0058] The polypropylene fiber used has an aspect ratio of 396, a bundled monofilament, and a density of 0.91 (g / cm 3 ,25℃,, elongation: 15%-35%, tensile strength: >400M1a; steel fiber aspect ratio 80, density: 7.8 (g / cm 3 ,25℃, tensile strength:>600M1a; basalt fiber aspect ratio 100, density: 2.85(g / cm 3 ,25℃,, elongation at break: 3.1%-3.2%, tensile strength:>800M1a.

[0059] Example 1

[0060] Table 1

[0061]

[0062] Example 2

[0063] Table 2

[0064]

[0065] Example 3

[0066] Table 3

[0067]

[0068] Example 4

[0069] Table 4

[0070]

[0071] Example 5

[0072] Table 5

[0073]

[0074] Example 6

[0075] Table 6

[0076]

[0077] The mechanical properties of the organic cementitious material test blocks prepared in Examples 1-6 were tested (in accordance with GB / 150081-2016), the flexural strength was tested by using a DKZ-5000 type electric flexural testing machine, and the compressive strength was tested by using a 1YE-300 pressure testing machine. As shown in Table 7, the flexural strength and compressive strength of the test blocks gradually increased with the increase of curing time. The doping of different types of fillers and fibers can affect the mechanical properties of the test blocks. Comparing Example 1 and Example 2, the flexural and compressive strengths of Example 1 were lower than those of Example 2, because the hardness of rubber particles was greater than that of rubber powder, so the mechanical properties of the test blocks could be improved. Different types of fibers also had an impact on the mechanical properties of the test blocks. Comparing Example 2, Example 3 and Example 4, the mechanical properties of the test blocks after the doping of polypropylene fibers were the highest. When three types of fibers were mixed and doped, the flexural and compressive properties of the test blocks of Example 5 and Example 6 were significantly improved compared with Example 2, Example 3 and Example 4, because the co-doping of different types of fibers could inhibit the generation of cracks in the test blocks from micro and macro dimensions, and improve the mechanical properties. In addition, the flexural and compressive strengths of the test blocks of Example 5 and Example 6 were similar, which proved that the change of the doping amount of afterglow force-induced fluorescent powder had little effect on the mechanical properties of the test blocks.

[0078] Table 7

[0079]

[0080] As examples of Example 2 and Example 5, the afterglow spectrum of the prepared test block was tested by a fluorescence spectrometer (FLUOROMAX-41, Horiba) under the following conditions: the test block was irradiated by 365 nm ultraviolet light for 5 minutes in a dark room, then the excitation source was removed, and after 1 minute of standing, the test block was placed in the spectrometer to test its afterglow emission spectrum. As shown in Figure 1 , the afterglow emission spectra of Example 5 and Example 6 test blocks are both asymmetric broad peaks, with the main peak of the emission peak being near 513 nm, and the emission peak being in the green region, indicating that both are green emission, which is attributed to the 5d-4f transition of Eu 2+ ions. The above results show that the prepared test block has self-luminous function, and the changes in the filler, fiber and afterglow force-induced fluorescent powder doping amount do not affect the self-luminous performance.

[0081] As examples of Example 2 and Example 5, the luminescent performance of the prepared test block under applied stress was tested by an optical fiber spectrometer and a universal testing machine to verify whether it has stress detection capability. The test conditions are as follows: the test block is placed under a bending press, the probe of the optical fiber spectrometer is aimed at the part of the test block in contact with the bending clamp, the press and the spectrometer are started, and it is observed whether the test block emits light, and the corresponding light system of the press force value and the test block luminous intensity is recorded. Figure 2 The emission spectrum of Example 2 and Example 5 under applied stress is shown in the figure. Without excitation by a light source, only under the action of external stress, until the test block is broken, it exhibits sustained luminescence, and the emission spectrum is an asymmetric broad band with the main peak near 510 nm, and the luminescence color is green, proving that the test block has luminescence response to applied stress. Figure 3 The relationship between the luminescent intensity and the applied stress of Example 2 and Example 5 under applied stress is shown in the figure. As shown in the figure, the stress luminescent intensity of the test block increases with the increase of the applied stress value, and the luminescent intensity decreases with the decrease of the applied stress, which indicates that the stress luminescent intensity and the applied stress size have a linear relationship, which is the basis for the non-contact stress self-detection of the prepared cementitious material. The above results show that the addition of afterglow force-induced fluorescent powder does not affect the mechanical properties of the material, and by combining the afterglow force-induced fluorescent powder and the resin-based material in a specific way, the prepared organic cementitious material can have both stress self-detection and luminescence performance without affecting the basic mechanical properties.

[0082] In addition, in order to realize accurate measurement of stress, as an example of Example 6, the luminescent intensity under different stress sizes was tested, and the functional relationship between the stress size and the luminescent intensity was calculated, as shown in Figure 4 . Through fitting calculation, the functional relationship between the stress size and the luminescent intensity is:

[0083] y = 0.5318x - 1.5 (1)

[0084] y is the detected luminescence intensity

[0085] x is the applied stress value

[0086] Example 7

[0087] In order to further verify that the organic cementitious material of the present application has stress detection function, a cylindrical sample with a diameter of 100 mm and a thickness of 70 mm is prepared by using conventional cement-based material, and a 5 mm wide crack is formed on the surface under the action of a press. The material prepared in Example 6 is injected into the crack, and after the material hardens, the press is used to apply external stress to the cylindrical sample, the luminescence intensity of the organic cementitious material at the crack is tested, and the stress value at the crack of the sample is calculated by formula (1), and the specific calculation results are shown in Table 8. The stress value calculated by the tested luminescence intensity is close to the value set by the pressure value, which proves that the organic cementitious material of the present application has stress monitoring and detection function

[0088] Table 8 Comparison results of set stress value and calculated stress value

[0089] Press set force value (N) Luminous intensity of the tested Calculated force value (N) 200 103.89 198.18 500 262.35 496.95 800 425.09 802.17 1200 638.53 1203.52

[0090] The above examples describe the basic principles, main features and advantages of the present application. The present application is not limited by the above examples, and the above examples and descriptions in the specification are only to illustrate the principles of the present application, and various changes and improvements can be made without departing from the scope of the principles of the present application, which are all within the scope of the claims of the present application and are protected by the patent law.

Claims

1. Stress-responsive luminescent organic gel, characterized by The components are as follows in parts by weight: epoxy resin 100-150 parts, curing agent 30-50 parts, toughening agent 10-30 parts, diluent 1-5 parts, defoaming agent 1-3 parts, filler 100-400 parts, residual luster fluorescent powder 10-30 parts, and additionally 1%-3% by mass of fiber; the toughening agent is any one of acrylate or polyurethane; the residual luster fluorescent powder is a mixture of one or both of europium and dysprosium doped strontium aluminate type fluorescent powder and over metal ion doped zinc sulfide type fluorescent powder; the filler is any one or a mixture of two of waste rubber particles, regenerated rubber particles, and rubber powder; the fiber is any one or a mixture of any of polypropylene fiber, steel fiber, and basalt fiber.

2. The stress-responsive luminescent organogel of claim 1, wherein The epoxy resin is bisphenol A type epoxy resin; the curing agent is any one of aliphatic amine or aromatic amine.

3. The stress-responsive luminescent organogel of claim 1, wherein The diluent is glycidyl ether; the defoaming agent is any one of alcohol, fatty acid, fatty acid ester, amide, organosilicon, or polyether modified polysiloxane.

4. The method of claim 1, wherein the stress-responsive luminescent organogel is prepared by The method comprises the following steps: (1) uniformly mixing and stirring epoxy resin, curing agent, toughening agent, diluent, and defoaming agent to obtain resin; (2) uniformly mixing residual luster fluorescent powder, filler, and fiber, pouring into a mold, oscillating and leveling, and obtaining the stress response type luminescent organic gel test block after curing and maintenance at room temperature.

5. A method of detecting stress in a building structure, characterized by The method comprises the following steps: mixing epoxy resin 100-150 parts, curing agent 30-50 parts, toughening agent 10-30 parts, diluent 1-5 parts, defoaming agent 1-3 parts, filler 100-400 parts, and residual luster fluorescent powder 10-30 parts by parts by weight, and additionally adding 1%-3% by mass of fiber; extruding the mixed material into the building structure stress detection part, drying and curing at room temperature, and judging stress change through luminescence; the toughening agent is any one of acrylate or polyurethane; the residual luster fluorescent powder is a mixture of one or both of europium and dysprosium doped strontium aluminate type fluorescent powder and over metal ion doped zinc sulfide type fluorescent powder; the filler is any one or a mixture of two of waste rubber particles, regenerated rubber particles, and rubber powder; the fiber is any one or a mixture of any of polypropylene fiber, steel fiber, and basalt fiber.

6. The building structure stress detection method according to claim 5, characterized in that The building structure stress detection part includes building structure cracks, load cracks, and deformation cracks.

7. The building structure stress detection method according to claim 5, characterized in that The method further comprises testing the luminescence intensity of the cured sample of the mixed material under different stress sizes, obtaining the simulation function relationship between stress size and luminescence intensity, and calculating the stress size through the luminescence intensity of the grouting material in the building structure stress detection part.

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