CN111220450A - Nondestructive detector for strength of lightweight aggregate concrete - Google Patents
Nondestructive detector for strength of lightweight aggregate concrete Download PDFInfo
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- CN111220450A CN111220450A CN201911414986.6A CN201911414986A CN111220450A CN 111220450 A CN111220450 A CN 111220450A CN 201911414986 A CN201911414986 A CN 201911414986A CN 111220450 A CN111220450 A CN 111220450A
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- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N3/30—Investigating strength properties of solid materials by application of mechanical stress by applying a single impulsive force, e.g. by falling weight
- G01N3/307—Investigating strength properties of solid materials by application of mechanical stress by applying a single impulsive force, e.g. by falling weight generated by a compressed or tensile-stressed spring; generated by pneumatic or hydraulic means
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N3/40—Investigating hardness or rebound hardness
- G01N3/52—Investigating hardness or rebound hardness by measuring extent of rebound of a striking body
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Abstract
The invention provides a nondestructive detector for the strength of light aggregate concrete, which comprises a fastening nut, a zero setting screw, a hook cylindrical pin, a button, a casing, an impact hammer, a tension spring seat, a snap ring, a sealing ring, an impact rod, a front cover, a buffering pressure spring, an impact tension spring, a graduated scale, a pointer sheet, a pointer block, a pointer shaft, a central guide rod, a guide flange, a hook pressure spring, a pressure spring and a tail cover. The invention provides a nondestructive detector for the strength of lightweight aggregate concrete, which uses impact energy much smaller than that of a common concrete resiliometer as the nominal kinetic energy of the lightweight aggregate concrete resiliometer.
Description
Technical Field
The invention belongs to the field of concrete quality detection, and particularly relates to a detection device for the strength of lightweight aggregate concrete.
Background
As is well known, the strength and quality of concrete are related to the overall safety and service life of a building structure, and therefore, the quality control, quality supervision and quality detection of concrete are very important in the whole life cycle of a building. The springback method is widely applied to construction engineering due to simple operation, convenient use, economy, rapidness and quite high detection precision.
In recent years, lightweight aggregate concrete has been widely used in various fields of construction engineering due to its characteristics of light weight, high strength, good heat insulation effect, excellent fire resistance and durability, and the like. At present, lightweight aggregate concrete has become a building material in an amount second to that of ordinary concrete. However, the research of the detection technology aiming at the lightweight aggregate concrete is almost blank at present, and the performance of the lightweight aggregate concrete is greatly different from that of the common concrete.
In the process of impacting the concrete surface by the aid of the resiliometer, the impact energy (nominal energy (0.50J +/-0.1000J)) of the resiliometer mainly comprises three parts: the energy absorbed to cause plastic deformation of the concrete; the concrete, the elastic striking rod and the elastic striking hammer generate elastic deformation work; the rebound energy.
It is proved by a lot of experimental studies that the work of elastically deforming concrete, a striking rod and a striking hammer is nearly constant under a certain impact energy, and therefore, the rebound distance depends on the plastic deformation of the concrete. Generally, when the strength grade is the same, the lightweight aggregate concrete has lower elastic modulus, lower strength and poor compactness compared with the common concrete, if a common concrete resiliometer (the nominal energy is not less than 2.207J) is adopted to impact the surface of the lightweight aggregate concrete, the plastic deformation of the lightweight aggregate concrete is inevitably larger, and the following rebound is influenced, and the correlation between the rebound value and the strength is poor due to the rebound energy (namely, the rebound value is smaller).
If the strength of the lightweight aggregate concrete is detected by adopting a common concrete resiliometer, a large error is inevitably generated, and great hidden danger is brought to the engineering quality. Therefore, it is necessary to develop a resiliometer specially suitable for detecting the strength of the structural lightweight aggregate concrete aiming at the characteristics of the lightweight aggregate concrete, so as to provide reliable quality assurance for the lightweight aggregate concrete engineering.
Disclosure of Invention
The invention aims to solve the defects in the prior art and provides a lightweight aggregate concrete strength nondestructive detector, which uses impact energy much smaller than that of a common concrete resiliometer as the nominal kinetic energy of the lightweight aggregate concrete resiliometer.
The invention adopts the following technical scheme:
a nondestructive detector for the strength of light aggregate concrete comprises a fastening nut, a zero setting screw, a hook cylindrical pin, a button, a shell, an impact hammer, a tension spring seat, a snap ring, a sealing ring, an impact rod, a front cover, a buffer pressure spring, an impact tension spring, a graduated scale, a pointer sheet, a pointer block, a pointer shaft, a central guide rod, a guide flange, a hook pressure spring, a tail cover and a conical part.
Zero adjusting screws are arranged inside and in the middle of the tail cover, fastening nuts are sleeved on the zero adjusting screws, and the depth of the zero adjusting screws screwed into the middle of the tail cover is adjusted through the fastening nuts.
The tail cover is connected with one end of the shell, the other end of the shell is connected with the front cover through the conical part, and the shell of the shell is provided with a button. The button is arranged in the shell, and one end of the button corresponds to the hook.
The couple is arranged inside the casing, and be located zero set screw lower part, couple one end is fixed on the guide flange through the couple cylindric lock, and catch on the impact hammer, couple other end connection couple pressure spring one end, the couple pressure spring is fixed on the guide flange, the pressure spring has been arranged between guide flange and the tail-hood, center guide arm one end is fixed on the guide flange, the impact hammer is installed at center guide arm middle part, center guide arm other end cover is on the impact pole, still arranged the buffering pressure spring between center guide arm tip and the impact pole, the tip of impact pole stretches out protecgulum center round hole, the impact hammer is hollow cylinder, the impact hammer overlaps on the center guide arm, the impact pole has the blind hole, its one end cover is at the center guide arm.
The protecgulum is hollow cone, and the protecgulum tip has arranged the sealing washer with the elastic striking pole contact department axial, and the snap ring is arranged in the sealing washer upside, and the extension spring seat is arranged in the snap ring upside, and the elastic striking extension spring cover is on the elastic striking pole to be located between extension spring seat and the elastic striking hammer.
The elastic hammer is connected with a pointer block fixed on a pointer shaft through a pointer sheet, one side of the pointer shaft is provided with a graduated scale, and the graduated scale and the pointer shaft are both arranged in the casing.
The sealing ring is divided into an upper part and a lower part, the upper part is a hollow circular ring, the lower circular ring of the sealing ring is in a hollow conical shape, and the sealing ring is arranged for preventing dust from entering from a gap between the spring seat and the striking rod.
The further technical scheme of the invention is that the rigidity of the spring impact tension spring is 178 +/-30.0N/m.
The further technical scheme of the invention is that the length of the pointer shaft is 20.0 +/-0.2 mm.
The further technical scheme of the invention is that the friction force of the pointer is as follows: 0.5 +/-0.1N.
The further technical scheme of the invention is that one end of the tapping rod is a spherical surface, and the radius of the spherical surface R25 +/-1.0 mm.
The further technical scheme of the invention is that the working length of the spring impact tension spring is 61.5 +/-0.3 mm.
The further technical scheme of the invention is that the impact length of the tapping rod is 75.0 +/-0.3 mm.
The further technical scheme of the invention is that a graduated scale at the take-off position of the elastic hammer is marked as '0' + 1.
The further technical scheme of the invention is that the rate fixed value on the steel anvil is as follows: 75 +/-2.
The further technical scheme of the invention is that the mass of the elastic striking hammer is 145 +/-2 g.
The further technical scheme of the invention is that the unhooking position of the elastic hammer is the marked line of the graduated scale 100.
The further technical scheme of the invention is that the diameter of the shell of the light aggregate concrete strength nondestructive detector is 50 mm.
The invention has the beneficial effects that:
(1) the invention limits each component, and correspondingly improves the length of the spring impact tension spring, the impact length of the spring impact hammer, the take-off position of the spring impact hammer, the rigidity of the spring impact tension spring, the radius of the spherical surface at the front end of the spring impact rod, the length of the pointer and the friction force, so that the whole detector has the function of detecting the strength of the light aggregate concrete.
(2) The invention is more suitable for lightweight aggregate concrete in the aspect of measuring the resilience and has higher strength measurement precision.
(3) The rebound values obtained by the lightweight aggregate concrete resiliometer designed by the invention on lightweight aggregate concrete with different strengths are more reasonably and uniformly distributed, and have more obvious correlation with the surface hardness and the actual compressive strength of the lightweight aggregate concrete.
(4) The distribution of resilience values is more uniformly dispersed when different concrete is rebounded, and the relevance of a concrete strength measuring curve established by proper nominal energy is better.
(5) When the radius of the spherical surface at the top end of the elastic striking rod is smaller, the absorption energy of the concrete surface is large, the rebound value is low, the detection precision is reduced, the test angle deviation of the resiliometer during use is easily caused, and when the radius of the spherical surface at the top end of the elastic striking rod is larger, the absorption energy of the concrete surface is smaller. Therefore, the utility model discloses the instrument is decided the bullet pole spherical radius between 24-26mm, has both guaranteed the interval rationality of resilience value, and the operation of being convenient for again reduces test angle deviation.
Drawings
FIG. 1 is a schematic structural view of the present invention;
fig. 2 is an enlarged view of the front cover gasket of fig. 1.
In the figure: 1-fastening nut, 2-zero set screw, 3-hook, 4-hook cylindrical pin, 5-button, 6-casing, 7-elastic hammer, 8-spring seat, 9-snap ring, 10-seal ring, 11-elastic rod, 12-front cover, 13-buffer pressure spring, 14-elastic tension spring, 15-graduated scale, 16-pointer sheet, 17-pointer block, 18-pointer shaft, 19-center guide rod, 20-guide flange, 21-hook pressure spring, 22-pressure spring, 23-tail cover and 24-taper part.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention are described below clearly and completely, and it is obvious that the described embodiments are some, not all embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Example 1.
As shown in fig. 1, the nondestructive detector for the strength of lightweight aggregate concrete of the invention comprises a fastening nut 1, a zero adjusting screw 2, a hook 3, a hook cylindrical pin 4, a button 5, a casing 6, a spring hammer 7, a tension spring seat 8, a snap ring 9, a seal ring 10, a spring rod 11, a front cover 12, a buffer compression spring 13, a spring tension spring 14, a scale 15, a pointer piece 16, a pointer block 17, a pointer shaft 18, a central guide rod 19, a guide flange 20, a hook compression spring 21, a compression spring 22, a tail cover 23 and a tapered part 24.
Zero set screw 2 is installed to inside, the mid-mounting of tail-hood 23, and the cover has fastening nut 1 on zero set screw 2, and zero set screw 2 passes through fastening nut 1 and adjusts the degree of depth in screw in tail-hood 23 middle part.
The tail cover 23 is arranged at one end of the machine shell 6, the other end of the machine shell 6 is connected with one end of the conical part 24 through threads, the other end of the conical part 24 is connected with the front cover 12, and the button 5 is arranged on the shell of the machine shell 6. The button 5 is arranged inside the shell 6, and one end of the button corresponds to the hook 3.
The hook 3 is arranged in the shell 6 and is positioned at the lower part of the zero adjusting screw 2, one end of the hook 3 is fixed on the guide flange 20 through the hook cylindrical pin 4, and catch the impact hammer 7, the other end of the hook 3 is connected with one end of a hook pressure spring 21, the other end of the hook pressure spring 21 is fixed on a guide flange 20, a pressure spring 22 is arranged between the guide flange 20 and a tail cover 23, one end of a central guide rod 19 is fixedly connected with the guide flange 20, the impact hammer 7 is installed in the middle of the central guide rod 19, the other end of the central guide rod 19 is sleeved on the impact rod 11, a buffer pressure spring 13 is further arranged between the end of the central guide rod 19 and the impact rod 11, the end of the impact rod 11 extends out of a central circular hole of a front cover 12, the impact hammer 7 is sleeved on the central guide rod 19 through an internal central hole, and the impact rod 11 is sleeved on the central guide rod 19 through an internal central blind hole (the impact hammer 7 is a hollow cylinder.
The front cover 12 is a hollow conical body, a sealing ring 10 is axially arranged at the contact position of the end part of the front cover 12 and the elastic striking rod 11, the upper part of the sealing ring 10 is a clamping ring 9, the upper part of the clamping ring is a tension spring seat 8, and an elastic striking tension spring 14 is sleeved on the elastic striking rod 11 and is positioned between the elastic striking hammer 7 and the tension spring seat 8. (the tension spring seat 8 is sleeved with two semicircular snap rings 9 in advance and then is placed into the front opening of the rebound apparatus front cover 12 to be clamped).
The elastic hammer 7 is connected with a pointer block 17 fixed on a pointer shaft 18 through a pointer sheet 16, a graduated scale 15 is arranged on one side of the pointer shaft 18, and both the graduated scale 15 and the pointer shaft 18 are arranged in a machine shell.
Experiments prove that when the resiliometer disclosed by the invention is used for bouncing the surface of the lightweight aggregate concrete, the obtained rebound value has better correlation with the strength of the lightweight aggregate concrete.
The further technical scheme of the invention is that the rigidity of the spring impact tension spring 14 is 178 +/-30.0N/m.
The further technical proposal of the invention is that the length of the pointer shaft 18 is 20.0 plus or minus 0.2 mm.
The further technical scheme of the invention is that the sliding friction force of the pointer block 17 is as follows: 0.5 +/-0.1N. The device is used for measuring the loss of a small part of impact kinetic energy caused by the movement of the pointer block on the pointer shaft.
The further technical scheme of the invention is that one end of the tapping rod 11 is a spherical surface, and the radius R25 + -1.0 mm of the spherical surface.
The further technical scheme of the invention is that the working length of the spring 14 is 61.5 +/-0.3 mm.
The further technical scheme of the invention is that the impact length of the tapping rod 11 is 75.0 +/-0.3 mm.
The further technical scheme of the invention is that a graduated scale at the take-off position of the elastic hammer 7 is marked as '0' + 1.
The further technical scheme of the invention is that the rate fixed value on the steel anvil is as follows: 75 +/-2.
The further technical proposal of the invention is that the mass of the elastic striking hammer 7 is 145 +/-2 g.
The further technical scheme of the invention is that the unhooking position of the elastic hammer 7 is the marked line of the graduated scale 100.
The further technical scheme of the invention is that the diameter of a casing 6 of the lightweight aggregate concrete strength nondestructive detector is 50 mm.
Example 2
As shown in fig. 1, the nondestructive detector for the strength of lightweight aggregate concrete of the invention comprises a fastening nut 1, a zero adjusting screw 2, a hook 3, a hook cylindrical pin 4, a button 5, a casing 6, a spring hammer 7, a tension spring seat 8, a snap ring 9, a seal ring 10, a spring rod 11, a front cover 12, a buffer compression spring 13, a spring tension spring 14, a scale 15, a pointer piece 16, a pointer block 17, a pointer shaft 18, a central guide rod 19, a guide flange 20, a hook compression spring 21, a compression spring 22, a tail cover 23 and a tapered part 24.
Zero set screw 2 is installed to inside, the mid-mounting of tail-hood 23, and the cover has fastening nut 1 on zero set screw 2, and zero set screw 2 passes through fastening nut 1 and adjusts the degree of depth in screw in tail-hood 23 middle part.
The tail cover 23 is arranged at one end of the machine shell 6, the other end of the machine shell 6 is connected with one end of the conical part 24 through threads, the other end of the conical part 24 is connected with the front cover 12, and the button 5 is arranged on the shell of the machine shell 6. The button 5 is arranged inside the shell 6, and one end of the button corresponds to the hook 3.
The hook 3 is arranged in the shell 6 and is positioned at the lower part of the zero adjusting screw 2, one end of the hook 3 is fixed on the guide flange 20 through the hook cylindrical pin 4, and catch the impact hammer 7, the other end of the hook 3 is connected with one end of a hook pressure spring 21, the other end of the hook pressure spring 21 is fixed on a guide flange 20, a pressure spring 22 is arranged between the guide flange 20 and a tail cover 23, one end of a central guide rod 19 is fixedly connected with the guide flange 20, the impact hammer 7 is installed in the middle of the central guide rod 19, the other end of the central guide rod 19 is sleeved on the impact rod 11, a buffer pressure spring 13 is further arranged between the end of the central guide rod 19 and the impact rod 11, the end of the impact rod 11 extends out of a central circular hole of a front cover 12, the impact hammer 7 is sleeved on the central guide rod 19 through an internal central hole, and the impact rod 11 is sleeved on the central guide rod 19 through an internal central blind hole (the impact hammer 7 is a hollow cylinder.
The front cover 12 is a hollow conical body, a sealing ring 10 is axially arranged at the contact position of the end part of the front cover 12 and the elastic striking rod 11, the upper part of the sealing ring 10 is a clamping ring 9, the upper part of the clamping ring is a tension spring seat 8, an elastic striking tension spring 14 is sleeved on the elastic striking rod 11 and is fixedly connected with the instrument shell through a spring seat 4 and a semicircular clamping ring 5 (the shell 6 and the conical part 24). (the tension spring seat 8 is sleeved with two semicircular snap rings 9 in advance and then is placed into the front opening of the rebound apparatus front cover 12 to be clamped).
Preferably, the sealing ring is divided into an upper part and a lower part, the upper part is a hollow circular ring, the lower circular ring of the sealing ring is in a hollow cone shape, and the sealing ring is arranged for preventing dust from entering from a gap between the spring seat and the striking rod.
The elastic hammer 7 is connected with a pointer block 17 fixed on a pointer shaft 18 through a pointer sheet 16, a graduated scale 15 is arranged on one side of the pointer shaft 18, and both the graduated scale 15 and the pointer shaft 18 are arranged in a machine shell.
Experiments prove that when the resiliometer disclosed by the invention is used for bouncing the surface of the lightweight aggregate concrete, the obtained rebound value has better correlation with the strength of the lightweight aggregate concrete.
The further technical scheme of the invention is that the rigidity of the spring impact tension spring 14 is 178 +/-30.0N/m.
The further technical proposal of the invention is that the length of the pointer shaft 18 is 20.0 plus or minus 0.2 mm.
The further technical scheme of the invention is that the sliding friction force of the pointer block 17 is as follows: 0.5 +/-0.1N.
The further technical scheme of the invention is that one end of the tapping rod 11 is a spherical surface, and the spherical radius R25 +/-1.0.
The further technical scheme of the invention is that the working length of the spring 14 is 61.5 +/-0.3 mm.
The further technical scheme of the invention is that the impact length of the tapping rod 11 is 75.0 +/-0.3 mm.
The further technical scheme of the invention is that a graduated scale at the take-off position of the elastic hammer 7 is marked as '0' + 1.
The further technical scheme of the invention is that the constant rate (rebound value) on the steel anvil is as follows: 75 +/-2.
The further technical proposal of the invention is that the mass of the elastic striking hammer 7 is 145 +/-2 g.
The further technical scheme of the invention is that the unhooking position of the elastic hammer 7 is the marked line of the graduated scale 100.
The further technical scheme of the invention is that the diameter of a casing 6 of the lightweight aggregate concrete strength nondestructive detector is 50 mm.
The use method of the invention comprises the following steps:
before testing, the surface of the lightweight aggregate concrete testing area should be ensured to be clean, dry and flat.
1) The axis of the resiliometer is pushed against the surface of the lightweight aggregate concrete, the axis of the resiliometer is always vertical to the surface of the lightweight aggregate concrete, the instrument is lightly pressed to release the button, the elastic striking rod 11 is slowly extended out, and the hook 3 is hung on the elastic striking hammer 7.
2) After the elastic hammer 7 is unhooked and impacts the elastic rod 11, the elastic hammer 7 drives the pointer piece 16 to move backwards until reaching a certain position, and the scale mark of the pointer block 17 indicates a certain rebound value on the scale 15.
3) And continuing to support the resiliometer against the surface of the lightweight aggregate concrete, reading and recording the rebound value, if the condition is unfavorable for reading, pressing the button 5 to lock the lock cylinder, and moving the resiliometer to the reading of the light aggregate concrete, wherein the reading is accurate to 1 unit.
4) Gradually reducing the pressure of the resiliometer to enable the elastic striking rod 11 to extend out of the shell, and hanging the elastic striking hammer 7 on the hook for next use.
In the actual engineering at the present stage, the strength detection of the structural lightweight aggregate concrete is usually performed by a rebound method by using a brick-testing resiliometer with the nominal energy of 0.735J. The special resiliometer for lightweight aggregate concrete disclosed by the invention has the advantages that the nominal energy of the resiliometer is properly reduced to 0.500J, so that the structure of the resiliometer is more reasonable, the rebound value intervals of lightweight aggregates with different strength grades are more uniform and continuous, the rebound detection precision of the lightweight aggregate concrete is further improved, and the special resiliometer is more suitable for detecting the structural lightweight aggregate concrete compared with a brick-testing resiliometer. This novel resiliometer strikes extension spring driven weight through the inside bullet of structure to strike the pole, thereby make the bullet strike the concrete surface, obtain the distance that the bullet struck the hammer and was rebounded, and come to express this distance and come to estimate the intensity of lightweight aggregate concrete according to the correlation of the compressive strength of resilience value and structure lightweight aggregate concrete with the resilience value.
Example 1.
The following parameters of the nondestructive detector for the strength of the lightweight aggregate concrete are adjusted:
the rigidity of the spring impact tension spring is 178 +/-30.0N/m; the working length of the spring impact tension spring is 61.5mm plus or minus 0.3 mm;
the impact length of the elastic striking rod is 75.0 +/-0.3 mm, and a graduated scale at the take-off position of the elastic striking hammer is marked as '0' + 1;
one end of the tapping rod is spherical, and the radius of the spherical surface R25 is plus or minus 1.0;
the length of the pointer shaft is 20.0 +/-0.2 mm; pointer friction force: 0.5 +/-0.1N.
When the lightweight aggregate concrete is detected, the rebound tester for the lightweight aggregate concrete reaches the nominal energy of 4.5J at the moment when the spring is bounced and the extension of the tension spring to the impact length of 75mm is released. The instrument of the invention obtains the structural lightweight aggregate concrete strength measurement curve formula with the correlation coefficient of 0.893, the relative standard deviation of 13.46 percent, the average relative error of 10.79 percent and the detection strength application range of 3.4MPa to 54.8MPa by detecting and researching 648 lightweight aggregate concrete test blocks with the strength grades of LC10-LC50 and the ages of 3d, 7d, 14d, 28d, 60d, 90d, 180d and 365d
The strength measurement curve formula of the lightweight aggregate concrete measured by the brick resiliometer is
The correlation coefficient was 0.843, the relative standard deviation was 15%, and the average relative error was 13.9%. The strength measurement curve measured by the brick resiliometer is compared and verified by the light aggregate concrete structure entity, the detection error of the instrument is very small, and the method is finishedThe precision requirement of on-site detection of the strength of the lightweight aggregate concrete is fully met.
The invention aims to improve the detection performance of the whole instrument and correctly reflect the normal working state of the resiliometer according to the principle, so that the assembly size of main parts of the machine core, the quality of the main parts and the assembly quality of the machine core are adjusted.
The experimental result shows that: the factors influencing the lightweight aggregate measurement result are mainly as follows: the working length of the spring impact tension spring, the impact length of the spring impact rod, the take-off position of the spring impact hammer, the rigidity of the spring impact tension spring, the radius of the front spherical surface of the spring impact rod, the length of the pointer and the friction force.
1. And the experimental results show that the strength value of the lightweight aggregate can be measured only by modifying all the structures. Assembling size of main parts of movement
Spring impact tension spring working length L0。L0The distance from the edge opening of the rear end of the tension spring seat to the large surface of the edge of the spring hanging hole of the elastic hammer is 61.5 mm. (namely, when the impact hammer is unhooked and impacts, the impact hammer collides with two impact surfaces of the impact rod at the moment, and the impact tension spring is in the length of the free state). If L is0>61.5mm, then the moment that the impact hammer strikes the impact rod, the extension spring is extruded, and the extension spring is restored to the free state L after the impact0>In the state of 61.5mm, a gap delta L is formed between two impact surfaces, so that the elastic hammer moves backwards by a distance delta L than the position specified by the design, the actual rebound energy is increased, and the measured rebound value is higher. If L is0<61.5mm, at the moment when the impact hammer impacts the impact rod, the tension spring can not be recovered to the free state, but is elongated by a length (-Delta L), so that the reverse tension force f needs to be overcome when the impact hammer rebounds, the actual rebound energy is reduced, and the measured rebound value is lower.
Impact length L of the striking rodp. Impact length L of the striking rodpThe distance between the two impact surfaces of the elastic hammer and the elastic rod is 75mm at the moment when the elastic hammer is unhooked. The instrument changes LpThe thickness of the concrete is more than or less than 75mm, and the test proves that L is obtained by performing parallel test on lightweight aggregate concrete with different hardnessp>75When the thickness is mm, the tension spring is extruded to enable the rebound value to be higher at the moment of collision between the elastic hammer and the elastic rod, but the rebound value is lower due to the fact that the take-off position of the elastic hammer is smaller than 0, and the displayed rebound value is slightly lower due to mutual offset. Conversely, a slightly higher rebound value results.
The kick position of the hammer. Namely the zero setting position of the resiliometer, the jumping position of the rebound hammer must be at the position corresponding to the graduated scale '0', the rebound tension spring is in a free state at the moment, and the working length is 61.5 mm. If the bounce position of the elastic striking hammer is not at '0' on the graduated scale, the elastic striking tension spring is extruded or stretched at the moment of collision between the elastic striking rod and the elastic striking tension spring, so that the impact energy of the rebound instrument set before can be changed, and the accuracy of the rebound value is influenced.
2. Mass of the main part
The rigidity of the spring is flicked. The rigidity of the spring-striking tension spring adopted by the application is 178.0N/m. The change of the rigidity of the tension spring directly influences the impact energy and the rebound value of the resiliometer. Through adopting 6 tension springs with the rigidity of 151.2N/m-204.6N/m to be arranged on three normal lightweight aggregate resiliometers, the same operator tests on four uniform lightweight aggregate concrete test blocks with different hardness, and the rebound value is found to be reduced along with the increase of the rigidity. When the rigidity of the spring impact tension spring is increased, the impact kinetic energy is increased, the plastic deformation generated on the surface of the light aggregate concrete is correspondingly increased, the rebound kinetic energy is reduced, and the rebound value is reduced.
The radius of the spherical surface at the front end of the tapping rod. The radius of the spherical surface at the front end of the tapping rod is designed to be 25 mm. Five lightweight aggregate concrete test blocks with different hardness are tested in parallel by the same operator by changing the radius (23-27mm) of the spherical surface at the front end of the tapping rod. It was found through experiments that the larger the radius, the higher the rebound value and tends to be remarkable as the surface hardness of the lightweight aggregate increases.
Pointer length and friction force. The design rule is that the indication value scale line of the pointer sliding block is positioned in the middle, the horizontal projection distance from the indication value scale line to the end part of the pointer is the length of the pointer, the design of the application is 20mm, and the indication value scale line has direct influence on the size of the rebound value. The pointer friction force is friction force f when a pointer block in a scale groove of the shell is pushed on the whole length of the guide rod, and the pointer friction force is designed to be 0.5N. The actual measurement shows that the friction force of the pointer is too small, and the pointer slides during rebounding, so that the rebound value is higher. Friction power is too big, influences the resilience force of elastic hammer, and the rebound value is on the low side, therefore pointer friction power should be controlled at 0.5 ~ 0.8N, and the resiliometer is suitable for a period of time back simultaneously, and the friction between pointer slider and the pointer axle can make the frictional force grow of pointer, so this application design value is 0.5N.
When the nondestructive detector works, the spring impact tension spring is stretched by acting force applied to the nondestructive detector, the pressure spring is compressed, the hook is unhooked, and the three parts of force are transmitted to the buffer pressure spring through the central guide rod, so that the buffer pressure spring is compressed by a certain length. Therefore, in order to ensure that the impact length of the impact hammer is 75mm, the mass of the impact tension spring, the compression spring and the buffering compression spring needs to be processed according to the design requirement so as to ensure the consistency of the mass of each resiliometer. In addition, when the elastic hammer is unhooked, the size of a hole between the tail of the hook and the upper plane of the guide flange also influences the jumping point of the elastic hammer. Therefore, it is desirable to process the nondestructive detector so that the unhooked tail is aligned with and minimizes the voids in the upper surface of the flange.
Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.
Claims (6)
1. The utility model provides a nondestructive detector of lightweight aggregate concrete intensity, includes fastening nut, zero set screw, couple cylindric lock, button, casing, impact hammer, extension spring seat, snap ring, sealing washer, impact pole, protecgulum, buffering pressure spring, impact extension spring, scale, pointer piece, pointer axle, central guide arm, guide flange, couple pressure spring, tail-hood, toper portion, its characterized in that:
zero-setting screws are arranged in the tail cover and in the middle of the tail cover, fastening nuts are sleeved on the zero-setting screws, and the depth of the zero-setting screws screwed into the middle of the tail cover is adjusted through the fastening nuts;
the tail cover is connected with one end of the shell, the other end of the shell is connected with the front cover through the conical part, a button is arranged on the shell of the shell and is arranged in the shell, and one end of the button corresponds to the hook;
the hook is arranged in the shell and positioned at the lower part of the zero setting screw, one end of the hook is fixed on the guide flange through the hook cylindrical pin and hooks the impact hammer, the other end of the hook is connected with one end of a hook pressure spring, the hook pressure spring is fixed on the guide flange, a pressure spring is arranged between the guide flange and the tail cover, one end of the central guide rod is fixed on the guide flange, the impact hammer is arranged in the middle of the central guide rod, the other end of the central guide rod is sleeved on the impact rod, a buffer pressure spring is also arranged between the end part of the central guide rod and the impact rod, the end part of the impact rod extends out of a central round hole of the front cover, the impact hammer is a hollow cylinder, the impact hammer is sleeved on the central;
the front cover is a hollow conical body, a sealing ring is axially arranged at the contact position of the end part of the front cover and the elastic striking rod, the clamping ring is arranged on the upper side of the sealing ring, the tension spring seat is arranged on the upper side of the clamping ring, and the elastic striking tension spring is sleeved on the elastic striking rod and is positioned between the tension spring seat and the elastic striking hammer;
the elastic hammer is connected with a pointer block fixed on a pointer shaft through a pointer sheet, one side of the pointer shaft is provided with a graduated scale, and the graduated scale and the pointer shaft are both arranged in the casing;
and adjusting the following parameters of the light aggregate concrete strength nondestructive detector:
the rigidity of the spring impact tension spring is 178 +/-30.0N/m; the working length of the spring impact tension spring is 61.5mm plus or minus 0.3 mm;
the impact length of the elastic striking rod is 75.0 +/-0.3 mm, and a graduated scale at the take-off position of the elastic striking hammer is marked as '0' + 1;
one end of the tapping rod is spherical, and the radius of the spherical surface R25 is plus or minus 1.0;
the length of the pointer shaft is 20.0 +/-0.2 mm; pointer friction force: 0.5 +/-0.1N.
2. The nondestructive detector of strength of lightweight aggregate concrete according to claim 1, wherein the mass of the impact hammer is 145 ± 2 g.
3. The nondestructive detector of lightweight aggregate concrete strength of claim 1, characterized in that the ratio on the steel anvil is fixed: 75 +/-2.
4. The nondestructive detector of lightweight aggregate concrete strength of claim 1, wherein the location of the unhooking of the impact hammer is at the scale "100" line.
5. The nondestructive detector of lightweight aggregate concrete strength according to claim 1, wherein a diameter of a housing of the nondestructive detector of lightweight aggregate concrete strength is 50 mm.
6. The nondestructive detector of lightweight aggregate concrete strength according to claim 1, wherein the seal ring is divided into an upper part and a lower part, the upper part is a hollow circular ring, the lower circular ring of the seal ring is a hollow conical ring, and the seal ring is provided to prevent dust from entering through a gap between the spring seat and the tapping rod.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911414986.6A CN111220450A (en) | 2019-12-31 | 2019-12-31 | Nondestructive detector for strength of lightweight aggregate concrete |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911414986.6A CN111220450A (en) | 2019-12-31 | 2019-12-31 | Nondestructive detector for strength of lightweight aggregate concrete |
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| CN111220450A true CN111220450A (en) | 2020-06-02 |
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| CN201911414986.6A Pending CN111220450A (en) | 2019-12-31 | 2019-12-31 | Nondestructive detector for strength of lightweight aggregate concrete |
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| CN111965060A (en) * | 2020-08-03 | 2020-11-20 | 河海大学 | Press-in type on-site modulus of resilience measuring device |
| CN112857970A (en) * | 2021-01-20 | 2021-05-28 | 国网江苏省电力工程咨询有限公司 | High-precision intelligent concrete resiliometer based on NB-IoT |
| CN112881156A (en) * | 2021-03-04 | 2021-06-01 | 南京工业大学 | Nondestructive detector for strength of lightweight aggregate concrete |
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| CN111965060A (en) * | 2020-08-03 | 2020-11-20 | 河海大学 | Press-in type on-site modulus of resilience measuring device |
| CN112857970A (en) * | 2021-01-20 | 2021-05-28 | 国网江苏省电力工程咨询有限公司 | High-precision intelligent concrete resiliometer based on NB-IoT |
| CN112881156A (en) * | 2021-03-04 | 2021-06-01 | 南京工业大学 | Nondestructive detector for strength of lightweight aggregate concrete |
| CN112881156B (en) * | 2021-03-04 | 2022-04-05 | 同济大学建筑设计研究院(集团)有限公司 | Nondestructive detector for strength of lightweight aggregate concrete |
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| CN113640162A (en) * | 2021-09-06 | 2021-11-12 | 中国化学工程第三建设有限公司 | Pneumatic concrete resiliometer device |
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| CN113640162B (en) * | 2021-09-06 | 2023-08-04 | 中国化学工程第三建设有限公司 | Pneumatic concrete resiliometer device |
| CN114264563A (en) * | 2021-12-27 | 2022-04-01 | 乐陵市回弹仪厂 | 3.503 Joule concrete resiliometer |
| CN114264563B (en) * | 2021-12-27 | 2024-05-03 | 乐陵市回弹仪厂 | 3.503J concrete resiliometer |
| CN116429615A (en) * | 2023-04-11 | 2023-07-14 | 广州大学 | Resiliometer for detecting strength of underwater concrete |
| CN116429615B (en) * | 2023-04-11 | 2024-03-29 | 广州大学 | Resiliometer for detecting strength of underwater concrete |
| CN116399740B (en) * | 2023-05-31 | 2023-08-15 | 山西八建集团有限公司 | On-spot acceptance device of building construction material |
| CN116399740A (en) * | 2023-05-31 | 2023-07-07 | 山西八建集团有限公司 | On-spot acceptance device of building construction material |
| CN116559002A (en) * | 2023-06-27 | 2023-08-08 | 慈溪市诚正建设工程检测有限公司 | Concrete strength detection device |
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