Intelligent device and method for measuring concrete volume shrinkage

Abstract

The present invention relates to an intelligent device and method for measuring concrete volume shrinkage. The device comprises a pressure sensing plate, a longitudinal distance measuring device, and a data processing center. The pressure sensing plate is horizontally placed on a plane and located below a concrete test block. Micro pressure sensors are arranged on the pressure sensing plate in orthogonal directions. The longitudinal distance measuring device comprises a scale measuring rope, a tension sensor, a fixed plate, a top plate, and an automatic adjustment motor. The bottom end of the scale measuring rope is fixed to the top surface of the concrete test block. The middle section of the scale measuring rope passes through a reserved hole on the fixed plate. The top end of the scale measuring rope is fixed to the tension sensor. A length probe is installed in the reserved hole of the fixed plate. The length probe obtains a length reading of the scale measuring rope on the fixed plate in real time. The automatic adjustment motor is fixed on the top plate. The top of the tension sensor is connected to the automatic adjustment motor. The data processing center can receive various basic data obtained by the pressure sensing plate and the longitudinal distance measuring device in real time.

Description

Technical Field

[0001] The present invention belongs to the technical field of concrete, and in particular relates to an intelligent device and method for measuring concrete volume shrinkage. Background Art

[0002] With the rapid development of large-scale infrastructure such as super-high-rise buildings, cross-sea bridges, undersea tunnels, and hydropower dams, the engineering community's requirements for the service performance of concrete materials have shifted from simply pursuing mechanical strength to ensuring durability throughout their entire lifecycle. Concrete's long-term volume stability, a key indicator affecting a structure's crack resistance, impermeability, and load-bearing capacity, directly determines the safe service life of major projects in complex environments such as salt corrosion, dry-wet cycles, and temperature fluctuations.

[0003] At present, the shrinkage detection of concrete in the industry mainly adopts methods such as handheld strain gauge method, standard frame micrometer method, vertical micrometer length measuring instrument method, embedded strain gauge method and bow screw micrometer method. However, these methods have certain limitations, which are mainly manifested as follows:

[0004] (1) It is a uniaxial measurement and cannot reflect the isotropic shrinkage characteristics of the three-dimensional layer, nor can it quantify the three-dimensional volume shrinkage value; (2) It is widely applicable to tests under conventional test environments, but for concrete structures serving in special environments (such as high temperature conditions), their shrinkage tests must simulate the actual working environment. Therefore, it is often necessary to frequently take and place the concrete test blocks, which greatly increases the risk of varying degrees of damage to the concrete test blocks due to human operating errors, thereby affecting the precision and accuracy of the concrete shrinkage test, and thus cannot provide reliable data reference for actual engineering.

[0005] Therefore, how to provide an intelligent device and method for measuring concrete volume shrinkage to overcome the shortcomings of traditional testing methods, improve the accuracy and applicability of concrete shrinkage testing methods, and ensure the safety of concrete structure projects is a technical problem that technical personnel in this field urgently need to solve. Summary of the Invention

[0006] The present invention provides an intelligent measurement device and method for concrete volume shrinkage. The device adopts a three-dimensional linkage intelligent testing device for concrete volume shrinkage, combined with a three-dimensional scale shrinkage fitting equation of concrete based on quality parameters and a concrete volume shrinkage fitting equation. Through real-time intelligent detection of the quality of concrete test blocks, the shrinkage values ​​of the three-dimensional scale and volume of concrete are automatically obtained, which significantly improves the accuracy and convenience of concrete shrinkage testing, overcomes the defects of human operation errors, meets the actual needs of different projects (especially special environments such as high temperature), ensures the safety of concrete structures, and promotes the intelligent and high-quality development of the concrete industry.

[0007] In order to solve the above technical problems, the present invention includes the following technical solutions:

[0008] An intelligent device for measuring concrete volume shrinkage, comprising:

[0009] A pressure sensing plate, the pressure sensing plate being placed horizontally on a plane and located below the concrete test block, with micro pressure sensors arranged orthogonally on the plate, and the vertex at the lower left corner of the pressure sensing plate serving as the origin;

[0010] A longitudinal distance measuring device, comprising a scale measuring rope, a tension sensor, a fixed plate, a top plate, and an automatic adjustment motor, wherein the height between the fixed plate and the pressure sensor plate plane is fixed, the bottom end of the scale measuring rope is fixed to the top surface of the concrete test block, the middle section of the scale measuring rope passes through a reserved hole on the fixed plate, the top end of the scale measuring rope is fixed to the tension sensor, a length probe is installed in the reserved hole of the fixed plate, the length probe obtains a real-time length reading of the scale measuring rope on the fixed plate, the automatic adjustment motor is fixed to the top plate, and the top of the tension sensor is connected to the automatic adjustment motor;

[0011] The data processing center can receive various basic data obtained by the pressure sensor plate and the longitudinal distance measuring device in real time, and perform data sorting, calculation and output operations.

[0012] Furthermore, a plane rectangular coordinate system is established in an orthogonal direction so that when the micro pressure sensor arranged thereon reads the pressure value, the coordinates of the micro pressure sensor having the pressure value reading on the plane rectangular coordinate system can be recorded simultaneously.

[0013] A method for intelligently measuring concrete volume shrinkage comprises the following steps:

[0014] Step S2: The automatic adjustment motor changes the height of the tension sensor by automatically adjusting the length of the connecting rope between the motor and the tension sensor, so that the measuring rope below the tension sensor is in a naturally hanging state. At this time, the reading of the tension sensor is exactly 0, and the automatic adjustment motor stops working. At this time, the reading of the length probe on the fixed plate is recorded as l0. The initial height of the concrete test block is z0=H-l0, where H is the height between the fixed plate and the pressure sensor plate.

[0015] Step S3: let the concrete test block stand for different time periods t1, t2, ..., t n At this time, the concrete specimen will shrink to different degrees in three dimensions. The mass of the concrete specimen m1, m2, ..., m at different times are recorded. n , length values ​​x1, x2, ..., x n , width values ​​y1, y2, ..., y n and height values ​​z1, z2, ..., z nand transmit these basic data to the data processing center;

[0016] Step S4: According to the basic data, fitting equations for the change of concrete block mass over time and the change of three-dimensional scale over time are obtained, which respectively conform to the following rules: m=k(t)=p ln (t+1)+q, x=f(t)=at 2 +bt+c,y=g(t)=k / (t+h)+d,z=h(t)=s+wt / (t 2 +e), where m is the mass of the concrete specimen, in g; x is the horizontal length of the concrete specimen, in mm; y is the longitudinal width of the concrete specimen, in mm; z is the vertical height of the concrete specimen, in mm; t is the standing time of the concrete specimen, in d; and the other symbols are related parameters of the fitting equation.

[0017] Furthermore, according to the volume formula of a cuboid V=x×y×z, the fitting equation of the change of concrete volume over time is obtained: V=P(t)=(at 2 +bt+c)∙(k / (t+h)+d)∙(s+wt / (t 2 +e)).

[0018] Furthermore, according to m=k(t), x=f(t), y=g(t) and z=h(t), the three-dimensional scale shrinkage fitting equation of concrete based on mass parameters is obtained: x=f(m)=aM 2 +bM+c,y=g(m)=k / (M+h)+d,z=h(m)=s+wM / (M 2 +e), where M = e (m-q) / p -1.

[0019] Furthermore, according to m=k(t) and V=P(t), the concrete volume shrinkage fitting equation based on quality parameters is obtained: V=P(m)=(aM 2 +bM+c)∙(k / (M+h)+d)∙(s+wt / (M 2 +e)), where M = e (m-q) / p -1.

[0020] Compared with the prior art, the beneficial effects of the present invention are mainly as follows:

[0021] (1) The intelligent concrete volume shrinkage measuring device provided by the present invention can simultaneously meet the real-time, intelligent and automated monitoring requirements of basic parameters such as the mass, length, width and height of concrete test blocks. It has high monitoring accuracy and a high degree of automation. The device has wide applicability, simple and reasonable structure and low cost, and has broad market promotion and application prospects.

[0022] (2) The intelligent measurement device and method for concrete volume shrinkage provided by the present invention are based on a three-dimensional linkage intelligent test device for concrete volume shrinkage, combined with a concrete three-dimensional scale shrinkage fitting equation based on quality parameters and a concrete volume shrinkage fitting equation. Only the single basic parameter of the concrete test block quality needs to be detected in real time, and the shrinkage value of the concrete three-dimensional scale and its volume can be automatically calculated. This method can significantly improve the accuracy and convenience of concrete shrinkage testing, overcome the defects of human operation errors, meet the actual needs of different projects (especially special environments such as high temperature), ensure the safety of concrete structures, and promote the intelligent and high-quality development of the concrete industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 Schematic diagram of the structure of the intelligent device for measuring concrete volume shrinkage in Example 1;

[0024] Figure 2 Schematic diagram of the pressure sensor plate in the intelligent device for measuring concrete volume shrinkage in Example 1.

[0025] In the figure,

[0026] 1-pressure sensing plate; 2-concrete test block; 3-micro pressure sensor; 4-scale measuring rope; 5-tension sensor; 6-fixed plate; 7-length probe; 8-top plate; 9-automatic adjustment motor; 10-data processing center. DETAILED DESCRIPTION

[0027] The following is a further detailed description of the intelligent device and method for measuring concrete volume shrinkage provided by the present invention in conjunction with specific embodiments. The advantages and features of the present invention will become more apparent from the following description.

[0028] The following combination Figure 1 and Figure 2 The intelligent device for measuring concrete volume shrinkage of the present invention is described in detail.

[0029] An intelligent device for measuring concrete volume shrinkage includes a pressure sensing plate 1, a longitudinal distance measuring device, and a data processing center 10. The pressure sensing plate 1 is placed horizontally on a plane and located below a concrete test block 2. Micro pressure sensors 3 are arranged orthogonally on the plate, with the lower left corner vertex of the pressure sensing plate 1 serving as the origin.

[0030] The longitudinal distance measuring device includes a scale measuring rope 4, a tension sensor 5, a fixed plate 6, a top plate 8, and an automatic adjustment motor 9. The height between the fixed plate 6 and the pressure sensor plate 1 is fixed. The bottom end of the scale measuring rope 4 is fixed to the top surface of the concrete test block 2. The middle section of the scale measuring rope 4 passes through the reserved hole on the fixed plate 6. The top end of the scale measuring rope 4 is fixed to the tension sensor 5. A length probe 7 is installed in the reserved hole of the fixed plate 6. The length probe 7 obtains the length reading of the scale measuring rope 4 on the fixed plate 6 in real time. The automatic adjustment motor 9 is fixed on the top plate 8, and the top of the tension sensor 5 is connected to the automatic adjustment motor 9.

[0031] The data processing center 10 can receive various basic data acquired by the pressure sensing plate 1 and the longitudinal distance measuring device in real time, and perform data sorting, calculation and output operations.

[0032] In this embodiment, it is more preferred to establish a plane rectangular coordinate system in an orthogonal direction so that when the micro pressure sensor 3 arranged thereon reads the pressure value, the coordinates of the micro pressure sensor 3 with the pressure value reading on the plane rectangular coordinate system can be recorded simultaneously.

[0033] Please continue to refer to Figure 1 and Figure 2 This embodiment also provides a method for intelligently measuring concrete volume shrinkage, comprising the following steps:

[0034] Step S2: The automatic adjustment motor 9 changes the height of the tension sensor 5 by automatically adjusting the length of the connecting rope between the automatic adjustment motor 9 and the tension sensor 5, so that the measuring rope below the tension sensor 5 is in a naturally hanging state. At this time, the reading of the tension sensor 5 is exactly 0, and the automatic adjustment motor 9 stops working. At this time, the reading l0 of the length probe 7 on the fixed plate 6 is recorded. The initial height of the concrete test block 2 is z0=H-l0, where H is the height between the fixed plate 6 and the pressure sensor plate 1;

[0035] Step S3: let the concrete test block 2 stand for different time periods t1, t2, ..., t n At this time, the concrete specimen 2 will shrink in different degrees in three dimensions. The mass of the concrete specimen 2 m1, m2, ..., m at different times are recorded. n , length values ​​x1, x2, ..., x n , width values ​​y1, y2, ..., y n and height values ​​z1, z2, ..., z n and transmit these basic data to the data processing center;

[0036] Step S4: According to the basic data, fitting equations for the change of concrete block mass over time and the change of three-dimensional scale over time are obtained, which respectively conform to the following rules: m=k(t)=p ln (t+1)+q, x=f(t)=at 2 +bt+c,y=g(t)=k / (t+h)+d,z=h(t)=s+wt / (t 2 +e), where m is the mass of the concrete specimen, in g; x is the horizontal length of the concrete specimen, in mm; y is the longitudinal width of the concrete specimen, in mm; z is the vertical height of the concrete specimen, in mm; t is the standing time of the concrete specimen, in d; and the other symbols are related parameters of the fitting equation.

[0037] In this embodiment, more preferably, according to the volume formula of a cuboid V=x×y×z, a fitting equation for the change of the concrete volume over time is obtained: V=P(t)=(at 2 +bt+c)∙(k / (t+h)+d)∙(s+wt / (t 2 +e)).

[0038] In this embodiment, more preferably, according to m=k(t), x=f(t), y=g(t) and z=h(t), the concrete three-dimensional scale shrinkage fitting equation based on the quality parameters is obtained: x=f(m)=aM 2 +bM+c,y=g(m)=k / (M+h)+d,z=h(m)=s+wM / (M 2 +e), where M = e (m-q) / p -1.

[0039] In this embodiment, more preferably, according to m=k(t) and V=P(t), the concrete volume shrinkage fitting equation based on the quality parameters is obtained: V=P(m)=(aM 2 +bM+c)∙(k / (M+h)+d)∙(s+wt / (M 2 +e)), where M = e (m-q) / p -1.

[0040] Three concrete specimens of typical strength were selected, and the concrete three-dimensional scale shrinkage fitting equation and concrete volume shrinkage fitting equation based on mass parameters of each specimen were measured through experiments. The specific parameters are shown in Table 1.

[0041] Table 1 Volume shrinkage mass substitution equations for three strength grades of concrete

[0042]

[0043] It can be seen that the intelligent measurement device for concrete volume shrinkage of the present invention is used to measure the intelligent volume shrinkage of concrete. Taking the C50 concrete in Table 1 as an example, its 28-day quality and shrinkage are measured:

[0044] The measured value of m = 9475.86 g was substituted into the concrete three-dimensional shrinkage fitting equation based on mass parameters. According to the corresponding equation coefficients in Table 1, the following equation can be obtained: x = f (m) = aM 2 +bM+c=399.838mm, y=g(m)=k / (M+h)+d=99.378mm, z=h(m)=s+wM / (M 2 +e)=99.181mm, further, the corresponding volume of concrete can be obtained by fitting the concrete volume shrinkage equation based on mass parameters: V=P(m)=(aM 2 +bM+c)∙(k / (M+h)+d)∙(s+wt / (M 2 +e))=3.94×10 6 mm 3 As can be seen from the above examples, by simply detecting a single basic parameter, concrete quality, in real time, the shrinkage values ​​of the concrete's three-dimensional dimensions and volume can be automatically calculated. This method can significantly improve the accuracy and convenience of concrete shrinkage testing, overcome the defects of human operating errors, meet the actual needs of different projects (especially special environments such as high temperatures), ensure the safety of concrete structures, and promote the intelligent and high-quality development of the concrete industry.

[0045] The above examples are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. The above embodiments only express several embodiments of the present invention, and their descriptions are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that for ordinary technicians in this field, without departing from the concept of the present invention, several variations and improvements can be made, which all fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent of the present invention shall be based on the attached claims.

Claims

1. An intelligent device for measuring concrete volume shrinkage, characterized in that: include: A pressure sensing plate, the pressure sensing plate being placed horizontally on a plane and located below the concrete test block, with micro pressure sensors arranged orthogonally on the plate, and the vertex at the lower left corner of the pressure sensing plate serving as the origin; A longitudinal distance measuring device, comprising a scale measuring rope, a tension sensor, a fixed plate, a top plate, and an automatic adjustment motor, wherein the height between the fixed plate and the pressure sensor plate plane is fixed, the bottom end of the scale measuring rope is fixed to the top surface of the concrete test block, the middle section of the scale measuring rope passes through a reserved hole on the fixed plate, the top end of the scale measuring rope is fixed to the tension sensor, a length probe is installed in the reserved hole of the fixed plate, the length probe obtains a real-time length reading of the scale measuring rope on the fixed plate, the automatic adjustment motor is fixed to the top plate, and the top of the tension sensor is connected to the automatic adjustment motor; The data processing center can receive various basic data obtained by the pressure sensor plate and the longitudinal distance measuring device in real time, and perform data sorting, calculation and output operations.

2. The intelligent device for measuring concrete volume shrinkage according to claim 1, characterized in that: A plane rectangular coordinate system is established in an orthogonal direction so that when the micro pressure sensor installed thereon reads the pressure value, the coordinates of the micro pressure sensor with the pressure value reading on the plane rectangular coordinate system can be recorded simultaneously.

3. An intelligent method for measuring concrete volume shrinkage, characterized in that: The intelligent device for measuring concrete volume shrinkage according to claim 1 or 2 comprises the following steps: Step S1, place the concrete test block forward on the pressure sensor plate, record the initial time t0 of the test and the initial mass m0 of the concrete, and at the same time, determine the initial rectangular area range of the bottom of the concrete test block through the coordinate position of the micro pressure sensor with pressure value reading on the coordinate system, and obtain the coordinates of each vertex of the initial rectangular area range of the bottom of the concrete test block, which are recorded as (x1, y1) (x2, y2) (x3, y3) (x4, y4) respectively. The initial horizontal length and width of the concrete are determined by the coordinates of each vertex, which are respectively , ; Step S2: The automatic adjustment motor changes the height of the tension sensor by automatically adjusting the length of the connecting rope between the motor and the tension sensor, so that the measuring rope below the tension sensor is in a naturally hanging state. At this time, the reading of the tension sensor is exactly 0, and the automatic adjustment motor stops working. At this time, the reading of the length probe on the fixed plate is recorded as l0. The initial height of the concrete test block is z0=H-l0, where H is the height between the fixed plate and the pressure sensor plate. Step S3: let the concrete test block stand for different time periods t1, t2, ⋯, t n At this time, the concrete specimen will shrink to different degrees in three dimensions. The mass of the concrete specimen m1, m2, ⋯, m at different times are recorded. n , length values ​​x1, x2, ⋯, x n , width values ​​y1, y2, ⋯, y n and height values ​​z1, z2, ⋯, z n and transmit these basic data to the data processing center; Step S4: According to the basic data, fitting equations for the change of concrete block mass over time and the change of three-dimensional scale over time are obtained, which respectively conform to the following rules: m=k(t)=p ln (t+1)+q, x=f(t)=at 2 +bt+c,y=g(t)=k / (t+h)+d,z=h(t)=s+wt / (t 2 +e), where m is the mass of the concrete specimen, in g; x is the horizontal length of the concrete specimen, in mm; y is the longitudinal width of the concrete specimen, in mm; z is the vertical height of the concrete specimen, in mm; t is the standing time of the concrete specimen, in d; and the other symbols are related parameters of the fitting equation.

4. The method according to claim 3, characterized in that According to the volume formula of a rectangular parallelepiped V=x×y×z, the fitting equation of the change of concrete volume over time is obtained: V=P(t)=(at 2 +bt+c)∙(k / (t+h)+d)∙(s+wt / (t 2 +e)).

5. The method according to claim 3, characterized in that: According to m=k(t), x=f(t), y=g(t) and z=h(t), the three-dimensional scale shrinkage fitting equation of concrete based on mass parameters is obtained: x=f(m)=aM 2 +bM+c,y=g(m)=k / (M+h)+d,z=h(m)=s+wM / (M 2 +e), where M = e (m-q) / p -1.

6. The method according to claim 3, characterized in that: According to m=k(t) and V=P(t), the concrete volume shrinkage fitting equation based on quality parameters is obtained: V=P(m)=(aM 2 +bM+c)∙(k / (M+h)+d)∙(s+wt / (M 2 +e)), where M = e (m -q) / p -1.

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