A high-precision pressure-sensitive sensor and a preparation method thereof

Abstract

This invention relates to the field of pressure-sensitive materials, specifically to a high-precision pressure-sensitive sensor and its preparation method. The high-precision pressure-sensitive sensor comprises functional filler, alkali-activated material, standard sand, and an alkaline activator; wherein the mass ratio of the functional filler, alkali-activated material, standard sand, and alkaline activator is 0.16-0.6:1:50-160:40-60. The advantages of this invention are: the pressure-sensitive sensor maintains low resistivity even with low carbon fiber content, and the resistivity of the sensor changes linearly with strain under pressure, exhibiting high precision, high stability, high repeatability, and high sensitivity.

Description

Technical Field

[0001] This invention relates to the field of pressure-sensitive materials, and more specifically to a high-precision pressure-sensitive sensor and its preparation method. Background Technology

[0002] Concrete is the most widely used engineering material in infrastructure construction, and researchers both domestically and internationally began studying its electrical conductivity in the 20th century. The resistivity of traditional concrete ranges from 10... 6 -10 9 Between Ω·cm, it can be considered an insulating material. However, adding a certain amount of conductive material to concrete can significantly reduce the resistivity of the material (1–10 Ω·cm). 4 Ω·cm). Based on this, different application directions have been developed according to the needs of different electrical conductivity and application scenarios. Among them, the research on the application of pressure-sensitive sensors for concrete structure damage has attracted much attention. At present, silicate cement-based materials are commonly used as matrix materials for pressure-sensitive sensors, but there are significant problems with the dispersion and bonding of carbon fibers in silicate cement: (1) In order to achieve the percolation threshold required by the conductive network, a high carbon fiber content is often required. However, excessive content not only increases the material cost, but may also have an adverse effect on the workability, uniformity and mechanical properties of concrete; (2) Poor bonding between carbon fibers and the matrix leads to a decrease in the accuracy, stability, repeatability and sensitivity of the sensor, and the electrical signal output by the sensor exhibits nonlinear changes.

[0003] Alkali-activated materials are produced by activating the activity of powders rich in silicon and aluminum oxides (such as blast furnace slag and ultrafine fly ash) using alkaline activators, resulting in a material with cementitious properties. Due to the presence of the alkaline activator, the pores of alkali-activated materials are typically rich in various types of ions, which enhance ionic conductivity. Therefore, alkali-activated materials are considered a promising alternative to silicate cement. Furthermore, ultrafine fly ash, with its unique spherical structure and "ball bearing" effect, promotes more uniform dispersion of carbon fibers, forming a stable conductive network and effectively improving the conductivity of pressure sensors. Surface modification techniques allow the carbon fiber surface to carry substances that can react with the Ca in the alkali-activated material. 2+ And Al 3+ The functional groups of the reaction further modulate the accuracy, stability, repeatability, and sensitivity of the pressure sensor's electrical signal. Summary of the Invention

[0004] This invention addresses the problems of poor dispersion of carbon fibers in the matrix material and poor interfacial bonding between matrices in existing pressure-sensitive sensors. It provides a high-precision pressure-sensitive sensor and its fabrication method. This pressure-sensitive sensor possesses the required mechanical properties, electrical conductivity, and pressure-sensitive properties, and is low in manufacturing cost and energy-saving and environmentally friendly.

[0005] The objective of this invention is achieved through the following technical solution:

[0006] In a first aspect, the present invention provides a high-precision pressure-sensitive sensor, which is composed of functional filler, alkali-activated material, standard sand and alkaline activator; wherein the mass ratio of functional filler, alkali-activated material, standard sand and alkaline activator is 0.16-0.6:1:50-160:40-60.

[0007] Preferably, the functional filler is carbon fiber treated with surfactant; wherein the mass ratio of surfactant to carbon fiber is 0.01-0.2:0.15-0.4.

[0008] Preferably, the alkali-activated material is a cementing material composed of blast furnace slag and ultrafine fly ash; wherein the mass ratio of blast furnace slag to ultrafine fly ash is 7-9:1-3.

[0009] Preferably, the surfactant is polyacrylamide (molecular formula: (C3H5NO)). n (CAS: 9003-05-8).

[0010] Preferably, the surfactant is a product obtained by in-situ polymerization of acrylamide monomer, the initiator is ammonium persulfate, the catalyst is TEMED, and the monomer:initiator:catalyst = 1:(0.001-0.005):(2.5-3.5).

[0011] Preferably, the blast furnace slag is S95 grade slag, and the main components of the blast furnace slag are CaO (40.03%), SiO2 (33.58%) and Al2O3 (14.59%), and the average particle size of the blast furnace slag is 12.23 μm.

[0012] Preferably, the main components of the ultrafine fly ash are SiO2 (57.79%), Al2O3 (14.28%) and CaO (8.06%), and the average particle size of the ultrafine fly ash is 1.82 μm.

[0013] Preferably, the standard sand is ISO standard sand.

[0014] Preferably, the carbon fiber is short-cut PAN-based carbon fiber with a diameter of 7 μm and a length of 6 mm.

[0015] Preferably, the mass ratio of the raw material components of the alkaline activator is: water:NaOH:water glass = 1:(0.34-1.17):(0.03-0.11).

[0016] More preferably, the modulus of the water glass in the alkaline activator ranges from 0.8 to 2.0, and the Na2O content in the water glass is 3% to 6%. The water-cement ratio is 0.38 to 0.45.

[0017] Secondly, the present invention provides a method for manufacturing a high-precision pressure-sensitive sensor, comprising the following steps:

[0018] (1) Mix water, NaOH and water glass in a predetermined ratio to prepare an alkaline activator, let it stand for 24 hours, and then proceed to the next experiment after cooling to room temperature;

[0019] (2) Mix the monomer, initiator and catalyst in proportion, and let the monomer undergo in-situ polymerization to obtain a polyacrylamide solution for later use;

[0020] (3) Take a certain mass of pre-prepared alkaline activator into a container, add polyacrylamide solution and stir in a stirring device until white polymer particles are produced to obtain carbon fiber dispersion.

[0021] (4) Add a certain amount of carbon fiber to the carbon fiber dispersion and place it in an ultrasonic device for ultrasonic stirring for 3 minutes to ensure that the carbon fiber and the carbon fiber dispersion are in full contact and undergo electrostatic adsorption reaction. A thin layer of surfactant is covered on the surface of the carbon fiber, which is the desired carbon fiber suspension.

[0022] (5) Weigh blast furnace slag and ultrafine fly ash into a mixing container according to the test plan and dry mix them. Then, while stirring, add the pre-prepared carbon fiber suspension. After all the suspension has been added, pour the remaining activator into the mixing pot and stir to obtain alkali-activated mortar.

[0023] (6) Pour alkali-activated mortar into the mold, and after vibration, insert electrode plates according to the requirements of 2cm for the inner and outer electrodes and 8cm for the inner electrodes. After curing for 1 day, demold and obtain the high-precision pressure sensor after steam curing at 60℃-80℃ for 1 day.

[0024] The beneficial effects of this invention are as follows:

[0025] 1. Polyacrylamide solution can uniformly coat the surface of carbon fibers, giving the carbon fiber surface a negative charge. Based on the principle of repulsion between like charges, the carbon fibers are separated from their aggregated state. Furthermore, the polyacrylamide molecule contains amide groups (-CONH2), which hydrolyze under alkaline conditions to generate carboxyl groups (-COOH). Then, it reacts with Ca... 2+ And Al 3+Complex chemical reactions occur to form corresponding products, thereby establishing chemical bonds between the geopolymer matrix and the carbon fibers. Furthermore, due to the presence of polymer chains, a cross-linked structure is formed, namely a carbon fiber-polymer "bridge"-geopolymer matrix structural system, which achieves superior interfacial adhesion performance through chemical adhesion.

[0026] 2. Compared with existing inventions, the advantages of this invention are: the pressure sensor still has a low resistivity under low carbon fiber content, and the resistivity of the sensor changes linearly with strain under pressure, thus possessing the characteristics of high precision, high stability, high repeatability and high sensitivity. Attached Figure Description

[0027] The present invention will be further described with reference to the accompanying drawings, but the embodiments in the drawings do not constitute any limitation on the present invention. For those skilled in the art, other drawings can be obtained based on the following drawings without creative effort.

[0028] Figure 1 This is a schematic diagram of the preparation method of a high-precision pressure-sensitive sensor provided in Embodiment 1 of the present invention.

[0029] Figure 2 This is a physical image of the pressure-sensitive sensor prepared in Example 1 of the present invention.

[0030] Figure 3 This is a graph showing the relationship between the resistance change rate (ΔR / R0) and strain over time of the pressure sensors of Embodiments 1-2 and Comparative Examples 1-2 of the present invention under cyclic loading (1.25MPa-25 MPa).

[0031] Figure 4 These are diagrams showing the pressure sensitivity accuracy and sensitivity of the pressure sensors in Embodiments 1-2 and Comparative Examples 1-2 of the present invention.

[0032] Figure 5 It is the chemical equation for the hydration reaction of polyacrylamide.

[0033] Figure 6 This is a SEM image of the product formed on the surface of carbon fiber inside an alkali-activated material matrix. Detailed Implementation

[0034] The technical solution of the present invention is illustrated below through specific examples. It should be understood that the one or more method steps mentioned in the present invention do not preclude the existence of other method steps before or after the combined steps, or the insertion of other method steps between these explicitly mentioned steps; it should also be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the present invention. Furthermore, unless otherwise stated, the numbering of each method step is merely a convenient tool for identifying each method step, and not for limiting the order of the method steps or defining the scope of the present invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the present invention.

[0035] To better understand the above technical solutions, exemplary embodiments of the present invention are described in more detail below. While exemplary embodiments of the present invention are shown, it should be understood that the present invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the present invention and to fully convey the scope of the invention to those skilled in the art.

[0036] The present invention will be further described below with reference to the following embodiments.

[0037] Example 1

[0038] A high-precision pressure-sensitive sensor is composed of functional filler, alkaline activating material, standard sand and alkaline activator.

[0039] The functional filler is mainly carbon fiber treated with surfactant, and the alkali-activated material is a cementing material composed of blast furnace slag and ultrafine fly ash.

[0040] The proportions of each component to the total mass of the cementitious material are as follows:

[0041] The blast furnace slag accounts for 70% of the total mass;

[0042] The ultrafine fly ash accounts for 30% by mass;

[0043] The carbon fiber accounts for 0.15% by mass;

[0044] The standard sand accounts for 135% of the total mass;

[0045] The surfactant comprises 0.01% by mass;

[0046] The alkaline activator accounts for 40% by mass.

[0047] The surfactant is produced by in-situ polymerization of acrylamide monomer, with ammonium persulfate as the initiator and TEMED as the catalyst, and the monomer:initiator:catalyst ratio being 1:0.001:2.5.

[0048] The mass ratio of the raw material components of the alkaline activator is: water:NaOH:water glass = 1:0.34:0.03.

[0049] The fabrication methods for high-precision pressure-sensitive sensors include:

[0050] (1) Mix water, NaOH and water glass in a predetermined ratio to prepare an alkaline activator, let stand for 24 hours, and wait for it to cool to room temperature.

[0051] (2) Mix the monomer, initiator and catalyst in proportion and stir for 10 min to allow the monomer to undergo in-situ polymerization to obtain a polyacrylamide solution.

[0052] (3) Take 22.5% of the mass of alkaline activator into a container to ensure that the carbon fiber is wetted. Then add polyacrylamide solution and stir in a stirring device until white polymer particles are produced. Continue stirring until the consistency is suitable to obtain the carbon fiber dispersion.

[0053] (4) Add carbon fiber to the carbon fiber dispersion and place it in an ultrasonic device for ultrasonic stirring for 3 minutes to ensure that the carbon fiber and the carbon fiber dispersion are in full contact and undergo electrostatic adsorption reaction. A thin layer of surfactant will be covered on the surface of the carbon fiber, which is the desired carbon fiber suspension.

[0054] (5) Weigh blast furnace slag and ultrafine fly ash into a mixing container according to the test plan and dry mix them. Then, while stirring, add the pre-prepared carbon fiber suspension. After all the suspension has been added, pour the remaining activator into the mixing pot and stir for 1 minute and 30 seconds. Then, add standard sand within 30 seconds and continue stirring for 4 minutes to obtain alkali-activated mortar.

[0055] (6) Pour alkali-activated mortar into the mold, and after vibration, insert electrode plates according to the requirements of 2cm for the inner and outer electrodes and 8cm for the inner electrodes. After curing for 1 day, demold and obtain a high-precision pressure sensor after steam curing at 60℃-80℃ for 1 day.

[0056] The resistivity test method employs the four-electrode method. A 3V DC voltage U is applied to the external electrode, and a current I is collected. The resistance R of the pressure sensor is calculated using Ohm's law, and then... The resistivity ρ is calculated. Based on... Figure 2 The sample was subjected to a cyclic load of 2kN-40kN at a rate of 2.5kN / s, and electrical signal data was collected simultaneously. Mechanical properties were tested using an INSTRON 5984 universal testing machine, with the compressive strength test performed at a compression rate of 2kN / s and the flexural strength test at a compression rate of 1mm / min.

[0057] The resistivity of the sample in Example 1 is shown in the table below:

[0058]

[0059] Example 2

[0060] A high-precision pressure-sensitive sensor is composed of functional filler, alkaline activating material, standard sand and alkaline activator.

[0061] The functional filler is mainly carbon fiber treated with surfactant, and the alkali-activated material is a cementing material composed of blast furnace slag and ultrafine fly ash.

[0062] The proportions of each component to the total mass of the cementitious material are as follows:

[0063] The blast furnace slag accounts for 70% of the total mass;

[0064] The ultrafine fly ash accounts for 30% by mass;

[0065] The carbon fiber accounts for 0.25% by mass;

[0066] The standard sand accounts for 135% of the total mass;

[0067] The surfactant comprises 0.01% by mass;

[0068] The alkaline activator accounts for 40% by mass.

[0069] The surfactant is produced by in-situ polymerization of acrylamide monomer, with ammonium persulfate as the initiator and TEMED as the catalyst, and the monomer:initiator:catalyst ratio being 1:0.001:2.5.

[0070] The mass ratio of the raw material components of the alkaline activator is: water:NaOH:water glass = 1:0.34:0.03.

[0071] The fabrication methods for high-precision pressure-sensitive sensors include:

[0072] (1) Mix water, NaOH and water glass in a predetermined ratio to prepare an alkaline activator, let stand for 24 hours, and wait for it to cool to room temperature.

[0073] (2) Mix the monomer, initiator and catalyst in proportion and stir for 10 min to allow the monomer to undergo in-situ polymerization to obtain a polyacrylamide solution.

[0074] (3) Take 27.5% of the mass of alkaline activator into a container to ensure that the carbon fiber is wetted. Then add polyacrylamide solution and stir in a stirring device until white polymer particles are produced. Continue stirring until the consistency is suitable to obtain the carbon fiber dispersion.

[0075] (4) Add carbon fiber to the carbon fiber dispersion and place it in an ultrasonic device for ultrasonic stirring for 3 minutes to ensure that the carbon fiber and the carbon fiber dispersion are in full contact and undergo electrostatic adsorption reaction. A thin layer of surfactant will be covered on the surface of the carbon fiber, which is the desired carbon fiber suspension.

[0076] (5) Weigh blast furnace slag and ultrafine fly ash into a mixing container according to the test plan and dry mix them. Then, while stirring, add the pre-prepared carbon fiber suspension. After all the suspension has been added, pour the remaining activator into the mixing pot and stir for 1 minute and 30 seconds. Then, add standard sand within 30 seconds and continue stirring for 4 minutes to obtain alkali-activated mortar.

[0077] (6) Pour alkali-activated mortar into the mold, and after vibration, insert electrode plates according to the requirements of 2cm for the inner and outer electrodes and 8cm for the inner electrodes. After curing for 1 day, demold and steam curing at 60℃-80℃ for 1 day to obtain Example 2.

[0078] The testing method is the same as in Example 1.

[0079] The resistivity of the sample in Example 2 is shown in the table below:

[0080]

[0081] Comparative Example 1

[0082] A high-precision pressure-sensitive sensor is composed of functional filler, alkaline activating material, standard sand and alkaline activator.

[0083] The functional filler is mainly carbon fiber treated with a dispersant.

[0084] The alkali-activated material is a cementing material composed of blast furnace slag and ultrafine fly ash.

[0085] The proportions of each component to the total mass of the cementitious material are as follows:

[0086] The blast furnace slag accounts for 70% of the total mass;

[0087] The ultrafine fly ash accounts for 30% by mass;

[0088] The carbon fiber accounts for 0.15% by mass;

[0089] The standard sand accounts for 135% of the total mass;

[0090] The surfactant comprises 0.01% by mass;

[0091] The alkaline activator accounts for 40% by mass.

[0092] The mass ratio of the raw material components of the alkaline activator is: water:NaOH:water glass = 1:0.34:0.03.

[0093] The fabrication methods for high-precision pressure-sensitive sensors include:

[0094] (1) Mix water, NaOH and water glass in a predetermined ratio to prepare an alkaline activator, let stand for 24 hours, and wait for it to cool to room temperature;

[0095] (2) Take 22.5% of the mass of alkaline activator into a container to ensure that the carbon fiber is wetted. Then add the dispersant and stir in a stirring device. After the dispersant dissolves and the bubbles dissipate, the carbon fiber dispersion can be obtained.

[0096] (3) Add carbon fiber to the carbon fiber dispersion and place it in an ultrasonic device for ultrasonic stirring for 3 minutes to ensure that the carbon fiber and the carbon fiber dispersion are in full contact and that a thin film is formed on the surface of the carbon fiber. Finally, add a few drops of defoamer. This is the desired carbon fiber suspension.

[0097] (4) Weigh blast furnace slag and ultrafine fly ash into a mixing container according to the test plan and dry mix them. Then, while stirring, add the pre-made carbon fiber suspension. After all the activator is added, pour the remaining activator into the mixing pot and stir for 1 minute and 30 seconds. Then, add standard sand within 30 seconds and continue stirring for 4 minutes to obtain alkali-activated mortar.

[0098] (5) Pour alkali-activated mortar into the mold, and after vibration, insert electrode plates according to the requirements of 2cm for the inner and outer electrodes and 8cm for the inner electrodes. After curing for 1 day, demold and obtain Comparative Example 1 after steam curing at 60℃-80℃ for 1 day.

[0099] The above dispersant is methylcellulose (molecular formula: C). 20 H 38 O 11 (CAS: 9004-67-5).

[0100] The defoamer mentioned above is tributyl phosphate (molecular formula: C). 12 H 27 O4P, CAS: 126-73-8).

[0101] The testing method is the same as in Example 1.

[0102] The resistivity of the sample in Comparative Example 1 is shown in the table below:

[0103]

[0104] Comparative Example 2

[0105] A high-precision pressure-sensitive sensor is composed of functional filler, cement, standard sand and water.

[0106] The functional filler is mainly carbon fiber treated with a dispersant.

[0107] The proportions of each component to the total mass of the cementitious material are as follows:

[0108] The cement accounts for 100% of the total mass;

[0109] The carbon fiber accounts for 0.15% by mass;

[0110] The standard sand accounts for 135% of the total mass;

[0111] The dispersant comprises 0.4% by mass;

[0112] The water accounts for 40% of the total mass.

[0113] The fabrication methods for high-precision pressure-sensitive sensors include:

[0114] (1) Divide the water into two equal parts, add a dispersant to one part and stir for 2 minutes to obtain a carbon fiber dispersion.

[0115] (2) Add carbon fiber to the carbon fiber dispersion and place it in an ultrasonic device for ultrasonic stirring for 3 minutes to ensure that the carbon fiber and the carbon fiber dispersion are in full contact and that a thin film is formed on the surface of the carbon fiber. Finally, add a few drops of defoamer. This is the desired carbon fiber suspension.

[0116] (3) Weigh the cement according to the test plan, then add the pre-prepared carbon fiber suspension while stirring. After all the cement has been added, add the remaining water to the container and stir for 1 minute and 30 seconds. Then add the standard sand within 30 seconds and continue stirring for 4 minutes to obtain cement mortar.

[0117] (4) Pour cement mortar into the mold, and after vibration, insert electrode plates according to the requirements of 2cm for the inner and outer electrodes and 8cm for the inner electrodes. After curing for 1 day, demold and obtain Comparative Example 2 after high temperature steam curing at 60℃-80℃ for 1 day.

[0118] The dispersant used above is the same as that used in Comparative Example 1.

[0119] The defoamer mentioned above is the same as that in Comparative Example 1.

[0120] The testing method is the same as in Example 1.

[0121] The resistivity of the sample in Comparative Example 2 is shown in the table below:

[0122]

[0123] Additionally, see Figure 3 and Figure 4 . Figure 3This is a graph showing the relationship between the resistance change rate (ΔR / R0) and strain over time of the pressure sensors of Embodiments 1-2 and Comparative Examples 1-2 of the present invention under cyclic loading (1.25MPa-25 MPa). Figure 4 This refers to the pressure sensitivity accuracy and sensitivity of the pressure sensors in Embodiments 1-2 and Comparative Examples 1-2 of the present invention.

[0124] Depend on Figure 3 It can be seen that, comparing the resistance change rate and strain of Examples 1-2 and Comparative Examples 1-2, Examples 1 and 2 show a better correspondence, and the peak value of the resistance change rate is around 30%. The resistance change rate curve does not show signal clutter, indicating good signal output quality and potential as a pressure-sensitive sensor. The peak values ​​of the resistance change rate of Comparative Examples 1 and 2 are much lower than those of Examples 1 and 2.

[0125] Figure 4 It can be seen that during the entire cyclic loading / unloading process of Examples 1-2 and Comparative Examples 1-2, the linear correlation between the resistance change rate and strain in Examples 1 and 2 is close to 1, indicating that the pressure sensors of Examples 1 and 2 possess high precision characteristics and maintain linear change throughout the monitoring process. In contrast, the precision of Comparative Examples 1 and 2 is far inferior to that of the Examples, maintaining high sensitivity and precision only under low strain conditions, falling far short of the requirements for high-precision pressure sensors.

[0126] See Figures 5 to 6 The surfactant molecule contains an amide group (-CONH2), which hydrolyzes under alkaline conditions to generate a carboxyl group (-COOH). Then it reacts with Ca... 2+ And Al 3+ Complex chemical reactions occur to form corresponding products, thereby establishing chemical bonds between the geopolymer matrix and the carbon fibers. Due to the presence of polymer chains, a cross-linked structure is formed, namely a carbon fiber-polymer "bridge"-geomer matrix structure system. The presence of polymer "bridges" fills the gaps between the carbon fibers and the geopolymer matrix, and the dense polymer network can dissipate the energy of cracking through network conformational deformation or physical entanglement points along the chains, preventing relative slippage between the fibers and the matrix. Relying on chemical adhesion forces, superior interfacial bonding performance is obtained.

[0127] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. The illustrative expressions of the above terms in this specification should not be construed as necessarily referring to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. In addition, those skilled in the art can combine and integrate the different embodiments or examples described in this specification.

[0128] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A high-precision pressure-sensitive sensor, characterized by, The high-precision pressure-sensitive sensor is composed of functional filler, alkali-activated material, standard sand and alkaline activator; wherein the mass ratio of the functional filler, alkali-activated material, standard sand and alkaline activator is 0.16-0.6:1:50-160:40-60; The functional filler is carbon fiber treated by surfactant; wherein the mass ratio of surfactant and carbon fiber is 0.01-0.2:0.15-0.4; The surfactant is polyacrylamide, and the surfactant is a product obtained by in-situ polymerization of acrylamide monomer, the initiator is ammonium persulfate, and the catalyst is TEMED, and the monomer: initiator: catalyst = 1: (0.001-0.005): (2.5-3.5).

2. A high precision pressure sensitive sensor according to claim 1, wherein The alkali-activated material is a cementing material composed of blast furnace slag and ultra-fine fly ash; wherein the mass ratio of blast furnace slag and ultra-fine fly ash is 7-9:1-3.

3. A high precision pressure sensitive sensor according to claim 2, wherein The blast furnace slag is S95 grade slag, and the average particle size of the blast furnace slag is 12.23 μm.

4. A high precision pressure sensitive sensor according to claim 2, wherein The average particle size of the ultra-fine fly ash is 1.82 μm; and the standard sand is ISO standard sand.

5. A high precision pressure sensitive sensor according to claim 1, wherein The carbon fiber is short PAN-based carbon fiber, with a diameter of 7 μm and a length of 6 mm.

6. A high precision pressure sensitive sensor according to claim 1, wherein The mass ratio of raw material components of the alkaline activator is: water: NaOH: water glass = 1: (0.34-1.17): (0.03-0.11).

7. A high precision pressure sensitive sensor according to claim 6, wherein The modulus of the water glass in the alkaline activator ranges from 0.8 to 2.0, and the Na2O content in the water glass is 3%-6%, and the water-cement ratio is 0.38-0.

45.

8. A method of manufacturing the high-precision pressure-sensitive sensor according to claim 1, characterized by, The method comprises the following steps: (1) mixing water, NaOH and water glass according to a predetermined ratio to prepare an alkaline activator, and standing for 24 h, and then carrying out the next step experiment after cooling to room temperature; (2) mixing monomer, initiator and catalyst according to a predetermined ratio to make the monomer undergo in-situ polymerization reaction to obtain a polyacrylamide solution for standby; (3) taking the prepared alkaline activator into a container, adding the polyacrylamide solution into a stirring device to stir until white polymer particles are generated, and then obtaining a carbon fiber dispersion liquid; (4) adding carbon fiber into the carbon fiber dispersion liquid, and placing into an ultrasonic device to ultrasonically stir for 3 min, so as to ensure that the carbon fiber and the carbon fiber dispersion liquid are in sufficient contact and electrostatic adsorption reaction, and a layer of surfactant is covered on the surface of the carbon fiber, thereby obtaining a carbon fiber suspension; (5) according to the test scheme, taking blast furnace slag and ultra-fine fly ash into a stirring container to dry mix, then adding the prepared carbon fiber suspension into the stirring container while stirring, and then pouring the remaining activator into the stirring pot, and stirring to obtain an alkali-activated mortar; (6) pouring the alkali-activated mortar into a mold, inserting electrode sheets according to the requirements of 2 cm of inner-outer electrode spacing and 8 cm of inner electrode spacing after vibrating, and then demolding after curing for 1 d, and then obtaining the high-precision pressure-sensitive sensor after high-temperature steam curing at 60°C-80°C for 1 d.

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