High-precision pressure-sensitive sensor and preparation method thereof

Abstract

The invention relates to the field of pressure-sensitive materials, in particular to a high-precision pressure-sensitive sensor and a preparation method thereof, and the high-precision pressure-sensitive sensor is composed of a functional filler, an alkali excitation material, standard sand and an alkali activator; wherein the mass ratio of the functional filler to the alkali excitation material to the standard sand to the alkali excitation agent is (0.16-0.6): 1: (50-160): (40-60). The pressure-sensitive sensor has the advantages that the pressure-sensitive sensor still has lower resistivity under the condition of lower carbon fiber mixing amount, the resistivity of the sensor and the change of strain are in linear change under the pressure effect, and the pressure-sensitive sensor has the characteristics of high precision, high stability, high repeatability and high sensitivity.

Description

Technical Field

[0001] The present invention relates to the field of pressure-sensitive materials, and in particular to a high-precision pressure-sensitive sensor and a preparation method thereof. Background Art

[0002] Concrete is the most widely used engineering material in infrastructure construction. Domestic and foreign researchers have studied the electrical conductivity of concrete since the 20th century. The resistivity of traditional concrete ranges from 10 6 -10 9 Ω·cm, it can be regarded as an insulating material. Adding a certain amount of conductive material to concrete can greatly reduce the resistivity of the material (1 to 10 4 Ω·cm). On this basis, different application directions are developed according to the needs of different conductivity and usage scenarios. Among them, the research on pressure-sensitive sensors applied to concrete structure damage has attracted much attention. At present, silicate cement-based materials are more common as the matrix material of 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 for the conductive network, a higher 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) The poor bonding between carbon fiber and the matrix leads to reduced accuracy, stability, repeatability and sensitivity of the sensor, and the electrical signal output by the sensor shows nonlinear changes.

[0003] Alkali-activated materials are materials that react to generate gelling properties by activating the activity of powders rich in silicon and aluminum oxides (such as blast furnace slag, ultrafine fly ash, etc.) with alkaline activators. Due to the presence of alkaline activators, the pores of alkali-activated materials are usually rich in various types of ions. The presence of these ions enhances the ionic conductivity. Therefore, alkali-activated materials are also considered to be a very promising alternative to silicate cement. In addition, ultrafine fly ash has a special spherical structure and a "ball bearing" effect, which can promote a more uniform dispersion of carbon fibers to form a stable conductive network, and can effectively improve the conductive properties of pressure-sensitive sensors. Through surface modification technology, the surface of the carbon fibers can carry a conductive material that can interact with the Ca in the alkali-activated material. 2+ and Al 3+ The reactive functional groups further regulate the accuracy, stability, repeatability and sensitivity of the electrical signal of the pressure-sensitive sensor. Summary of the invention

[0004] In view of the problems of the dispersion of carbon fiber in the matrix material and the poor interface bonding performance between the matrixes in the existing pressure-sensitive sensors, the present invention provides a high-precision pressure-sensitive sensor and a preparation method thereof. The pressure-sensitive sensor has the required mechanical properties, conductive properties and pressure-sensitive properties, and has a low preparation cost and is energy-saving and environmentally friendly.

[0005] The purpose of the present invention is achieved by the following technical solutions:

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

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

[0008] Preferably, the alkali-activated material is a cementitious 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 blast furnace slag are CaO (40.03%), SiO 2 (33.58%) and Al 2 O 3 (14.59%), and the average particle size of blast furnace slag is 12.23 μm.

[0012] Preferably, the main component of the ultrafine fly ash is SiO 2 (57.79%), Al 2 O 3 (14.28%) and CaO (8.06%), the average particle size of ultrafine fly ash is 1.82μm.

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

[0014] Preferably, the carbon fiber is chopped 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 range of the water glass in the alkaline activator is 0.8-2.0, and the Na 2 O content is 3%-6%. Water-cement ratio is 0.38-0.45.

[0017] In a second aspect, the present invention provides a method for preparing a high-precision pressure-sensitive sensor, comprising the following steps:

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

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

[0020] (3) taking a certain amount of prefabricated alkaline activator into a container, adding polyacrylamide solution and stirring in a stirring device until white polymer particles are produced to obtain a carbon fiber dispersion;

[0021] (4) Add a certain amount of carbon fiber to the carbon fiber dispersion and put it into an ultrasonic device for ultrasonic stirring for 3 minutes to ensure that the carbon fiber and the carbon fiber dispersion are fully in contact and an electrostatic adsorption reaction occurs. A thin layer of surfactant is covered on the surface of the carbon fiber. At this time, the desired carbon fiber suspension is obtained;

[0022] (5) According to the test plan, blast furnace slag and ultrafine fly ash are weighed and dry mixed in a stirring container, and then the prefabricated carbon fiber suspension is added while stirring. After the addition is complete, the remaining activator is poured into a stirring pot and stirred to obtain an alkali-activated mortar.

[0023] (6) pouring alkali-activated mortar into the mold, inserting the electrode sheet after vibration according to the requirements of 2 cm between the inner and outer electrodes and 8 cm between the inner and outer electrodes, and demolding after curing for 1 day, and obtaining the high-precision pressure-sensitive sensor after high-temperature steam curing at 60° C.-80° C. for 1 day.

[0024] The beneficial effects of the present invention are:

[0025] 1. The polyacrylamide solution can be evenly coated on the surface of the carbon fiber, making the carbon fiber surface carry negative charge. According to the principle of mutual repulsion of like charges, the carbon fiber is separated from the agglomerated state. In addition, the molecular structure of polyacrylamide contains amide groups (-CONH 2 ), which is hydrolyzed under alkaline conditions to form a carboxyl group (-COOH). Then it reacts with Ca 2+ and Al3+ A complex chemical reaction occurs to form the corresponding products, thus establishing a chemical bond between the geopolymer matrix and the carbon fiber. And due to the presence of polymer chains, a cross-linked structure is formed, that is, the structural system of carbon fiber-polymer "bridge"-geopolymer matrix, relying on chemical adhesion to obtain better interface bonding performance.

[0026] 2. Compared with the existing inventions, the advantages of the present invention are that the pressure-sensitive sensor still has a low resistivity under the condition of low carbon fiber content, and the resistivity of the sensor changes linearly with the strain under the action of pressure, and it has the characteristics of high precision, high stability, high repeatability and high sensitivity. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The present invention is further described using the accompanying drawings, but the embodiments in the accompanying drawings do not constitute any limitation to the present invention. A person skilled in the art can obtain other drawings based on the following drawings without creative work.

[0028] Figure 1 It is a schematic diagram of the steps of a method for preparing a high-precision pressure-sensitive sensor provided in Example 1 of the present invention.

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

[0030] Figure 3 The resistance change rate (ΔR / R) of the pressure-sensitive sensors of Examples 1-2 and Comparative Examples 1-2 of the present invention under cyclic load (1.25 MPa-25 MPa) is 0 ) and the relationship between strain and time.

[0031] Figure 4 It is a diagram of the pressure-sensitive accuracy and sensitivity of the pressure-sensitive sensors of Examples 1-2 of the present invention and Comparative Examples 1-2.

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

[0033] Figure 6 This is an SEM image of the product formed by carbon fibers on the surface inside the alkali-activated material matrix. DETAILED DESCRIPTION

[0034] The technical solution of the present invention is described below through specific examples. It should be understood that the one or more method steps mentioned in the present invention do not exclude the existence of other method steps before and after the combination step or the insertion of other method steps between these explicitly mentioned steps; it should also be understood that these embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention. Moreover, unless otherwise specified, the numbering of each method step is only a convenient tool for identifying each method step, and is not intended to limit the order of arrangement of each method step or to limit the scope of the present invention. The change or adjustment of the relative relationship thereof shall also be regarded as the scope of the present invention without substantially changing the technical content.

[0035] In order to better understand the above technical scheme, the exemplary embodiments of the present invention are described in more detail below. Although 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 by the embodiments set forth herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present invention and to enable the scope of the present invention to be fully communicated to those skilled in the art.

[0036] The present invention will be further described below in conjunction with the following examples.

[0037] Example 1

[0038] The invention discloses a high-precision pressure-sensitive sensor, which is composed of functional filler, alkali-exciting material, standard sand and alkaline activator.

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

[0040] Among them, the proportion of each component to the total mass of the cementitious material is as follows:

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

[0042] The mass of the ultra-fine fly ash accounts for 30%;

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

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

[0045] The mass of the surfactant accounts for 0.01%;

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

[0047] The surfactant is prepared by in-situ polymerization of acrylamide monomer, the initiator is ammonium persulfate, the catalyst is TEMED, and the ratio of monomer:initiator:catalyst is 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 preparation method of the high-precision pressure-sensitive sensor includes:

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

[0051] (2) The monomer, initiator and catalyst are mixed in proportion and stirred for 10 minutes to allow the monomer to undergo in situ polymerization to obtain a polyacrylamide solution.

[0052] (3) Take 22.5% of the mass of the alkaline activator into a container to ensure that the carbon fiber is soaked. At this time, add the polyacrylamide solution and stir in a stirring device until white polymer particles are produced. At this time, 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 fully in contact and an electrostatic adsorption reaction occurs. A thin layer of surfactant is covered on the surface of the carbon fiber. At this time, the desired carbon fiber suspension is obtained.

[0054] (5) According to the test plan, blast furnace slag and ultrafine fly ash were weighed and dry mixed in a stirring container. Then, the prefabricated carbon fiber suspension was added while stirring. After the addition was complete, the remaining activator was poured into the stirring pot. After stirring for 1 min 30 s, standard sand was added within 30 s and stirring was continued for 4 min to obtain alkali-activated mortar.

[0055] (6) Alkali-activated mortar is poured into the mold, and after vibration, the electrode sheet is inserted according to the requirements that the inner and outer electrode spacing is 2 cm and the inner electrode spacing is 8 cm. After curing for 1 day, the mold is removed, and a high-precision pressure-sensitive sensor is obtained after high-temperature steam curing at 60°C-80°C for 1 day.

[0056] The resistivity test method adopts the four-electrode method. By applying a 3V DC voltage U to the outer electrode and collecting the current I, the resistance R of the pressure sensitive sensor is calculated according to Ohm's law. The resistivity ρ is calculated. Figure 2 The wiring method was used to apply a cyclic load of 2kN-40kN to the sample at 2.5kN / s, and the electrical signal data was collected at the same time. The mechanical properties test was carried out using an INSTRON5984 universal testing machine, where the pressure rate for the compressive strength test was 2kN / s and the pressure rate for the flexural strength test was 1mm / min.

[0057] The resistivity of the samples of Example 1 is shown in the following table:

[0058]

[0059] Example 2

[0060] The invention discloses a high-precision pressure-sensitive sensor, which is composed of functional filler, alkali-exciting material, standard sand and alkaline activator.

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

[0062] Among them, the proportion of each component to the total mass of the cementitious material is as follows:

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

[0064] The mass of the ultra-fine fly ash accounts for 30%;

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

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

[0067] The mass of the surfactant accounts for 0.01%;

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

[0069] The surfactant is prepared by in-situ polymerization of acrylamide monomer, the initiator is ammonium persulfate, the catalyst is TEMED, and the ratio of monomer:initiator:catalyst is 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 preparation method of the high-precision pressure-sensitive sensor includes:

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

[0073] (2) The monomer, initiator and catalyst are mixed in proportion and stirred for 10 minutes to allow the monomer to undergo in situ polymerization to obtain a polyacrylamide solution.

[0074] (3) Take 27.5% of the mass of the alkaline activator into a container to ensure that the carbon fiber is soaked. Then add the polyacrylamide solution and stir in a stirring device until white polymer particles are produced. Continue stirring until the consistency is suitable to obtain a 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 fully in contact and an electrostatic adsorption reaction occurs. A thin layer of surfactant is covered on the surface of the carbon fiber. At this time, the desired carbon fiber suspension is obtained.

[0076] (5) According to the test plan, blast furnace slag and ultrafine fly ash were weighed and dry mixed in a stirring container. Then, the prefabricated carbon fiber suspension was added while stirring. After the addition was complete, the remaining activator was poured into the stirring pot. After stirring for 1 min 30 s, standard sand was added within 30 s and stirring was continued for 4 min to obtain alkali-activated mortar.

[0077] (6) Alkali-activated mortar was poured into the mold, and after vibration, the electrode sheets were inserted according to the requirements of 2 cm between the inner and outer electrodes and 8 cm between the inner and outer electrodes. After curing for 1 day, the mold was removed, and Example 2 was obtained after high-temperature steam curing at 60° C.-80° C. for 1 day.

[0078] The test method is consistent with that in Example 1.

[0079] The resistivity of the samples of Example 2 is shown in the following table:

[0080]

[0081] Comparative Example 1

[0082] The invention discloses a high-precision pressure-sensitive sensor, which is composed of functional filler, alkali-exciting 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 cementitious material composed of blast furnace slag and ultra-fine fly ash.

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

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

[0087] The mass of the ultra-fine fly ash accounts for 30%;

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

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

[0090] The mass of the surfactant accounts for 0.01%;

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

[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 preparation method of the high-precision pressure-sensitive sensor includes:

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

[0095] (2) Take 22.5% of the mass of the alkaline activator into a container to ensure that the carbon fiber is soaked. At this time, add the dispersant and stir in a stirring device. After the dispersant is dissolved 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 fully in contact and the surface of the carbon fiber is covered with a thin film. Finally, add a few drops of defoaming agent. This is the desired carbon fiber suspension.

[0097] (4) According to the test plan, blast furnace slag and ultrafine fly ash were weighed and dry mixed in a stirring container. Then, the prefabricated carbon fiber suspension was added while stirring. After the addition was complete, the remaining activator was poured into the stirring pot. After stirring for 1 min 30 s, standard sand was added within 30 s and stirring was continued for 4 min to obtain alkali-activated mortar.

[0098] (5) Alkali-activated mortar was poured into the mold, and after vibration, the electrode sheets were inserted according to the requirements that the inner and outer electrode spacing was 2 cm and the inner electrode spacing was 8 cm. After curing for 1 day, the mold was removed, and after high-temperature steam curing at 60° C.-80° C. for 1 day, Comparative Example 1 was obtained.

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

[0100] The above defoamer is tributyl phosphate (molecular formula: C 12 H 27 O 4 P, CAS: 126-73-8).

[0101] The test method is consistent with that in Example 1.

[0102] The resistivity of the samples of Comparative Example 1 is shown in the following table:

[0103]

[0104] Comparative Example 2

[0105] The invention discloses a high-precision pressure-sensitive sensor, which is composed of functional filler, cement, standard sand and water.

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

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

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

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

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

[0111] The mass of the dispersant accounts for 0.4%;

[0112] The water accounts for 40% by mass.

[0113] The preparation method of the high-precision pressure-sensitive sensor includes:

[0114] (1) Divide the water into two parts, add dispersant into one part and stir for 2 minutes to obtain 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 fully in contact and the surface of the carbon fiber is covered with a thin film. Finally, add a few drops of defoaming agent. This is the desired carbon fiber suspension.

[0116] (3) According to the test plan, cement was weighed and then added to the prefabricated carbon fiber suspension while stirring. After the addition was complete, the remaining water was added to the container and stirred for 1 min 30 s. Standard sand was added within 30 s and the mixture was stirred for 4 min to obtain cement mortar.

[0117] (4) Cement mortar was poured into the mold, and after vibration, electrode sheets were inserted according to the requirements that the inner and outer electrode spacing was 2 cm and the inner electrode spacing was 8 cm. After curing for 1 day, the mold was removed, and the mold was cured at a high temperature of 60° C.-80° C. for 1 day to obtain Comparative Example 2.

[0118] The above dispersant is consistent with Comparative Example 1.

[0119] The above defoamer is consistent with Comparative Example 1.

[0120] The test method is consistent with that in Example 1.

[0121] The resistivity of the samples of Comparative Example 2 is shown in the following table:

[0122]

[0123] Also, see Figure 3 and Figure 4 . Figure 3The resistance change rate (ΔR / R) of the pressure-sensitive sensors of Examples 1-2 and Comparative Examples 1-2 of the present invention under cyclic load (1.25 MPa-25 MPa) is 0 ) and the relationship between strain and time. Figure 4 It is the pressure-sensitive accuracy and sensitivity of the pressure-sensitive sensors of Examples 1-2 of the present invention and Comparative Examples 1-2.

[0124] Depend on Figure 3 It can be seen that by comparing the resistance change rate and strain of Examples 1-2 and Comparative Examples 1-2, Example 1 and Example 2 have a good corresponding relationship, and the resistance change rate peak is around 30%, and the resistance change rate curve does not show signal clutter, indicating that the signal output quality is good and has the potential to be used as a pressure-sensitive sensor. The resistance change rate peaks of Comparative Examples 1 and 2 are much lower than those of Examples 1 and 2.

[0125] Figure 4 It can be seen that in the entire cyclic loading / unloading process of Examples 1-2 and Comparative Examples 1-2, the linear correlation between the resistance change rate and the strain of Examples 1 and 2 is close to 1, indicating that the pressure-sensitive sensors of Examples 1 and 2 have high-precision characteristics and maintain linear changes throughout the monitoring process. However, the accuracy of Comparative Examples 1 and 2 is far inferior to that of the Examples, and they can only maintain high sensitivity and accuracy under low strain conditions, which is far from meeting the requirements of high-precision pressure-sensitive sensors.

[0126] See also Figures 5 and 6 The surfactant molecular structure contains an amide group (-CONH 2 ), which is hydrolyzed under alkaline conditions to form a carboxyl group (-COOH). Then it reacts with Ca 2+ and Al 3+ Complex chemical reactions occur to form corresponding products, thereby establishing a chemical bond between the geopolymer matrix and the carbon fiber, and due to the presence of the polymer chain, a cross-linked structure is formed, that is, the structural system of carbon fiber-polymer "bridge"-geopolymer matrix. The presence of the polymer "bridge" fills the gap between the carbon fiber and the geopolymer matrix, and the dense polymer network can consume the energy of cracking through network conformation deformation or sliding physical entanglement points along the chain, preventing relative slippage between the fiber and the matrix, and relying on chemical adhesion to obtain better interfacial bonding performance.

[0127] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms should not be understood as necessarily being directed to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine different embodiments or examples described in this specification.

[0128] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A high-precision pressure-sensitive sensor, characterized in that: The high-precision pressure-sensitive sensor is composed of functional filler, alkali-excitation material, standard sand and alkaline activator; wherein the mass ratio of the functional filler, alkali-excitation material, standard sand and alkaline activator is 0.16-0.6:1:50-160:40-60.

2. A high-precision pressure-sensitive sensor according to claim 1, characterized in that: The functional filler is carbon fiber treated with a surfactant; wherein the mass ratio of the surfactant to the carbon fiber is 0.01-0.2:0.15-0.

4.

3. A high-precision pressure-sensitive sensor according to claim 1, characterized in that: The alkali-activated material is a cementitious 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.

4. A high-precision pressure-sensitive sensor according to claim 1, characterized in that: The surfactant is polyacrylamide, which is a product obtained by in-situ polymerization of acrylamide monomers. The initiator is ammonium persulfate, and the catalyst is TEMED. The monomer:initiator:catalyst=1:(0.001-0.005):(2.5-3.5).

5. The high-precision pressure-sensitive sensor according to claim 1, characterized in that: The blast furnace slag is S95 grade slag, and the average particle size of the blast furnace slag is 12.23 μm.

6. The high-precision pressure-sensitive sensor according to claim 1, characterized in that: The average particle size of the ultrafine fly ash is 1.82 μm; the standard sand is ISO standard sand.

7. The high-precision pressure-sensitive sensor according to claim 1, characterized in that: The carbon fiber is short-cut PAN-based carbon fiber with a diameter of 7 μm and a length of 6 mm.

8. The high-precision pressure-sensitive sensor according to claim 1, characterized in that: 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).

9. A high-precision pressure-sensitive sensor according to claim 8, characterized in that: The modulus range of the water glass in the alkaline activator is 0.8-2.0, the content of Na2O in the water glass is 3%-6%, and the water-cement ratio is 0.38-0.

45.

10. A method for preparing the high-precision pressure-sensitive sensor according to claim 1, characterized in that: The steps include: (1) Mix water, NaOH and water glass in a preset ratio to prepare an alkaline activator, let it stand for 24 hours, and then proceed to the next step of the experiment after cooling to room temperature; (2) mixing the monomer, initiator and catalyst in proportion, and causing the monomer to undergo in-situ polymerization to obtain a polyacrylamide solution for standby use; (3) taking the pre-made alkaline activator into a container, adding the polyacrylamide solution and stirring in a stirring device until white polymer particles are produced to obtain a carbon fiber dispersion; (4) Add carbon fiber to the carbon fiber dispersion, put it into an ultrasonic device for ultrasonic stirring for 3 minutes, ensure that the carbon fiber and the carbon fiber dispersion are fully in contact and electrostatic adsorption reaction occurs, and the surface of the carbon fiber is covered with a layer of surfactant, which is the desired carbon fiber suspension; (5) According to the test plan, blast furnace slag and ultrafine fly ash are weighed and dry mixed in a stirring container, and then the prefabricated carbon fiber suspension is added while stirring. After the addition is completed, the remaining activator is poured into the stirring pot and stirred to obtain an alkali-activated mortar; (6) pouring alkali-activated mortar into the mold, inserting the electrode sheet after vibration according to the requirements of 2 cm between the inner and outer electrodes and 8 cm between the inner and outer electrodes, and demolding after curing for 1 day, and obtaining the high-precision pressure-sensitive sensor after high-temperature steam curing at 60° C.-80° C. for 1 day.

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