Concrete mixture aggregate segregation resistance testing device and application method

Abstract

The invention belongs to the technical field of traffic engineering material mixture aggregate detection, and provides a concrete mixture aggregate segregation resistance testing device and method.The mixture separation mechanism comprises a first charging barrel and a second charging barrel which are detachably connected through a fixing column, and a sealing mechanism is arranged at the joint of the first charging barrel and the second charging barrel; a partition plate is rotationally arranged on the fixing column and located at the position of the sealing mechanism; when a concrete mixture is layered in the first charging barrel and the second charging barrel, the first charging barrel and the second charging barrel can be separated by rotating the partition plate, so that the layered concrete mixture is separated for subsequent testing, the first charging barrel and the second charging barrel are separated by rotating the partition plate, and the device is simple in structure and convenient to use. The problem of material leakage during material taking after separation can be avoided; meanwhile, a water spraying pipe is arranged in the screening mechanism, washing and screening of the layered concrete mixture are achieved, aggregate with few impurities is obtained, and the accuracy of aggregate weighing in the later period is guaranteed.

Description

Technical Field

[0001] This invention belongs to the field of aggregate testing technology for transportation engineering materials, and particularly relates to a device and application method for testing the anti-segregation performance of aggregates in concrete mixtures. Background Technology

[0002] To test the segregation resistance of aggregates in concrete mixtures, various test methods for concrete aggregate segregation have been designed. Representative methods include visual inspection, the viscous paste falling ball method, and segregation resistance test methods in relevant standards. Addressing the limitations of these methods in quantitatively determining the degree of segregation in concrete mixtures and characterizing the settling or floating of aggregates of different particle sizes, a dynamic segregation detection device for concrete was designed.

[0003] Current concrete dynamic segregation testing devices are not only structurally complex, but also require intricate mechanisms to effectively separate and extract different material from the concrete after stratification. Simpler methods of material separation can lead to issues like material leakage, affecting experimental accuracy and failing to balance the trade-off between testing time and precision. Furthermore, using water as the dispersion medium for separating cement paste and aggregates results in a longer dosage and a longer time required for complete separation, further exacerbating the tension between testing time and precision. Summary of the Invention

[0004] To address the aforementioned problems, this invention proposes a testing device and application method for the anti-segregation performance of aggregates in concrete mixtures. The device separates the first and second material cylinders using a rotating partition, resulting in a simple structure that avoids material leakage during separation. Simultaneously, a water spray pipe is incorporated into the screening mechanism, working in conjunction with the invention's efficient composite dispersion liquid, to achieve rapid and high-quality rinsing and screening of the stratified concrete mixture, yielding aggregates with fewer impurities and ensuring accurate weighing of the aggregates later.

[0005] To achieve the above objectives, in a first aspect, the present invention provides a device for testing the anti-segregation performance of aggregates in concrete mixtures, employing the following technical solution: A device for testing the anti-segregation performance of aggregates in concrete mixtures includes a mixture separation mechanism for separating the concrete mixture into layers, and a screening mechanism for washing and screening the separated concrete mixture. The mixture separation mechanism includes a first material cylinder and a second material cylinder detachably connected by a fixed column. A sealing mechanism is provided at the connection between the first material cylinder and the second material cylinder. A partition is rotatably provided on the fixed column at the location of the sealing mechanism. After the concrete mixture is stratified in the first material cylinder and the second material cylinder, the first material cylinder and the second material cylinder are separated by rotating the partition, thereby realizing the separation of the stratified concrete mixture. The screening mechanism includes a sieve and a water spray pipe disposed inside the sieve, the water spray pipe realizing the rinsing and screening of the stratified concrete mixture.

[0006] Furthermore, at least two ear plates are provided on the first and second material cylinders respectively, and the ear plates are provided with connecting holes; the fixing post is a screw, and a first nut is fixed on the screw, and a second nut is detachably provided on the screw; the head of the screw fits into the connecting hole of the second material cylinder, and the first nut and the second nut fit into the two sides of the connecting hole of the first material cylinder respectively.

[0007] Furthermore, a rotating ring is provided on the connecting column, and the partition is fixed on the rotating ring; a fixed ring is also provided on the connecting column, and the rotating ring is in contact with the fixed ring.

[0008] Furthermore, the sealing mechanism includes an annular sealing assembly and a sealing ring disposed inside the sealing assembly.

[0009] Furthermore, the sealing mechanism is mounted on the first material cylinder via a telescopic rod.

[0010] Furthermore, a limit block is provided on the outer wall of the second barrel.

[0011] Furthermore, the edges of the partition are beveled.

[0012] Furthermore, the thickness of the partition is 5mm to 8mm, the chamfer angle on the edge of the partition is 30°, and the rotation speed of the partition is 10° / s.

[0013] Furthermore, the sieve is a cylindrical sieve, and a drive shaft is rotatably mounted on the sieve. A brush and a water spray pipe are mounted on the drive shaft. A water pump and a motor are mounted on the screening mechanism, and buffer pads are provided at both the water pump and the motor.

[0014] To achieve the above objectives, in a second aspect, the present invention also provides a method for applying a testing device for the anti-segregation performance of aggregates in concrete mixtures, employing the following technical solution: A method for applying a concrete mix aggregate anti-segregation performance testing device, as described in the first aspect, includes placing the mix separation mechanism on a preset vibration table for vibration, or placing the mix separation mechanism for a preset time; after the concrete mix has completed stratification in the first and second material cylinders, the sealing mechanism is removed, and the partition is rotated and inserted into the connection position between the first and second material cylinders to obtain the stratified concrete mix; The stratified concrete mixtures were placed into a screening mechanism for washing and screening to obtain aggregates, which were then weighed and tested.

[0015] Further, weigh three portions of raw materials and premix them separately, then add water and admixtures and continue stirring for a preset time; load the mixed concrete mixture into the first and second material cylinders, ensuring the concrete mixture is flush with the upper edge of the first material cylinder; place the concrete mixture in the first and second material cylinders on a vibrating table and vibrate for 30±5s; move the sealing mechanism upwards to expose the connection between the first and second material cylinders; rotate the partition tangentially towards the connection between the first and second material cylinders until the connection is completely separated; separate the first and second material cylinders; pour out and weigh the layered concrete mixtures separately, then mold concrete flexural and compressive strength specimens; clean the first and second material cylinders; pour the layered mixtures into a sieve, cover with a cover plate, and thoroughly rinse the concrete mixture; after the slurry in the concrete mixture is rinsed clean, remove the aggregates remaining from each layer of sieves, dry and weigh them separately; finally, sieve the aggregates remaining from each layer of sieves separately and compile the sieve data for each grade.

[0016] Furthermore, a composite dispersion is used to completely separate the cement paste from the aggregate. The preparation of the composite dispersion includes: Isopropyl triisostearoyl titanate was added to a four-necked flask; N2 protection was introduced, and the temperature was raised to 90°C. Under stirring, the mixture was dehydrated under vacuum for 30 min; the temperature was lowered to 65°C; acetylacetone was dissolved in anhydrous toluene at a ratio of Ti:β-diketone = 1:1.1, and added dropwise to the flask through a constant pressure dropping funnel. After the addition was complete, the reaction was continued at 75°C for 4 h; after the reaction was completed, isopropanol, excess acetylacetone, and solvent were removed by vacuum distillation at 60°C under N2 protection to obtain a β-diketone-modified titanate intermediate. Dissolve the intermediate in anhydrous toluene and place it back in a dry four-necked flask; add the catalyst p-toluenesulfonic acid, and weigh out short-chain methyl ether polyethylene glycol according to the ratio Ti: short-chain methyl ether polyethylene glycol = 1: 0.5; dissolve it in anhydrous toluene, and then add it dropwise to the reaction mixture through a constant pressure dropping funnel under N2 protection at 100°C; connect a water separator and continuously remove trace amounts of water or molecular alcohol generated in the reaction by toluene azeotropic reaction, and reflux the reaction at 110°C for 5 hours; After the reaction was completed, the mixture was cooled to room temperature. The reaction solution was washed with saturated NaHCO3 solution until neutral to remove the catalyst and acidic impurities. The mixture was then washed with deionized water, dried with anhydrous magnesium sulfate, filtered, and then evaporated under reduced pressure at 65°C to remove the toluene solvent. Low-boiling-point residues were removed at 100°C and under vacuum for 1 hour to obtain a brownish-red to amber liquid. Water, polycarboxylate superplasticizer, calcium alkylbenzene sulfonate, and polydimethyldiallyl ammonium chloride were placed in a liquid mixer at a mass ratio of 1:0.005:0.001:0.0001:0.0001 and mixed at 120 r / min for 10 min to obtain a composite dispersion.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. The concrete mixture separation mechanism of this invention includes a first material cylinder and a second material cylinder detachably connected by a fixed column, and a sealing mechanism is provided at the connection between the first material cylinder and the second material cylinder; a partition is rotatably provided on the fixed column at the location of the sealing mechanism; after the concrete mixture has completed stratification in the first material cylinder and the second material cylinder, the first material cylinder and the second material cylinder can be separated by rotating the partition, thereby separating the stratified concrete mixture for subsequent testing. Separating the first material cylinder and the second material cylinder by rotating the partition is simple in structure and can avoid the problem of material leakage when taking out material after separation; at the same time, a water spray pipe is provided in the screening mechanism to realize the washing and screening of the stratified concrete mixture, so as to obtain aggregate with fewer impurities and ensure the accuracy of aggregate weighing in the later stage.

[0018] 2. When the composite dispersion designed in this invention is used in conjunction with the proposed testing device, the composite dispersion can quickly and accurately test the anti-segregation performance of aggregates in various types of concrete, significantly reduce the amount of dispersion used, and significantly shorten the testing time. Attached Figure Description

[0019] The accompanying drawings, which form part of this embodiment, are used to provide a further understanding of this embodiment. The illustrative embodiments and their descriptions are used to explain this embodiment and do not constitute an improper limitation of this embodiment.

[0020] Figure 1 This is a mixture separation mechanism according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the sealing ring according to an embodiment of the present invention; Figure 3 This is a schematic diagram of the partition in an embodiment of the present invention; Figure 4 This is the screening mechanism in an embodiment of the present invention; Figure 5 This is a schematic diagram of a brush according to an embodiment of the present invention; Figure 6 This is a cross-sectional schematic diagram of the screening mechanism according to an embodiment of the present invention; Figure 7 This is a schematic cross-sectional view of the drive rod according to an embodiment of the present invention; Figure 8 This is a three-stage settling tank according to an embodiment of the present invention; Among them, 1. Mixture separation mechanism; 101. First material cylinder; 102. First nut; 103. Sealing assembly; 104. Limiting block; 105. Second material cylinder; 106. Fixing ring; 107. Partition plate; 108. Rotating ring; 109. Telescopic column; 110. Fixing rod; 111. Second nut; 112. Sealing ring; 113. Drive mechanism; 2. Screening mechanism; 201. Drive shaft; 202. Cover plate; 203. Screen; 204. Buffer pad; 205. Motor; 206. Water pump; 207. Base; 208. Guide channel; 209. Brush; 210. Spray pipe; 3. Three-stage settling tank; 301. Inlet; 302. Outlet. Detailed Implementation

[0021] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0022] It should be noted that the following detailed descriptions are exemplary and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0023] Concrete is a widely used and practical material in modern society. Aggregate is one of the most important raw materials in concrete, playing a role in its skeleton and filling function, typically accounting for more than 60% of the concrete volume. During the concrete mixing process, if the aggregate gradation design is unreasonable, it can easily cause aggregate settlement in the mixture, leading to segregation of the concrete mix, reducing the concrete strength and the integrity of the concrete structure, and thus shortening the service life of the concrete.

[0024] To test the segregation resistance of aggregates in concrete mixtures, numerous test methods for concrete aggregate stratification have been designed. Representative methods include visual inspection, the viscous paste falling ball method, and segregation resistance test methods in relevant standards. However, these methods cannot quantitatively determine the degree of segregation in the concrete mixture, nor can they characterize the settling or floating of aggregates of different particle sizes within the mixture. Therefore, existing technologies have designed dynamic segregation detection devices for concrete.

[0025] In actual experiments, it was found that visual inspection, relying solely on experience, could not quantitatively determine the degree of segregation in concrete mixtures. The viscous slurry drop ball method involves placing aggregates in a slurry of a certain viscosity and testing the settling velocity and distance. For ease of observation and measurement, transparent slurry tests are typically used. However, since concrete mixtures are opaque slurries, observation is difficult, and data obtained using alternative transparent slurries are less representative. Therefore, this method is primarily used for theoretical calculations and is rarely applied in practice. The relevant standard test method is currently the most commonly used method for testing the degree of aggregate segregation in concrete mixtures. This method involves placing the concrete mixture in a container and allowing it to stand for a period of time. Then, the lower section of the mixture is transferred to a 5.00mm square-hole sieve, and after standing, the mass of the slurry passing through the sieve is measured, and the segregation rate is calculated. This method can accurately test the anti-segregation performance of concrete mixtures, but it cannot characterize the settling or floating of aggregates of different particle sizes in the mixture. The current design of the concrete dynamic segregation detection device is not only complex in structure, but also requires a complex mechanism to achieve good separation and sampling of different material cylinders after the concrete is layered. Material cylinder separation achieved by a simple structure will have problems such as material leakage, which will affect the accuracy of the experiment.

[0026] In response to the above problems, such as Figure 1 and Figure 4 As shown, one embodiment of the present invention provides a test device for the anti-segregation performance of aggregates in concrete mixtures, including a mixture separation mechanism 1 for separating the concrete mixture into layers, and a screening mechanism 2 for washing and screening the separated concrete mixture. The mixture separation mechanism 1 includes a first material cylinder 101 and a second material cylinder 105 that are detachably connected by a fixed column 110. A sealing mechanism is provided at the connection between the first material cylinder 101 and the second material cylinder 105. A partition plate 107 is rotatably provided on the fixed column 110 at the position of the sealing mechanism. The screening mechanism 2 includes a sieve 203 and a water spray pipe 210 disposed inside the sieve 203.

[0027] Specifically, after the concrete mixture has been stratified in the first material cylinder 101 and the second material cylinder 105, the first material cylinder 101 and the second material cylinder 105 can be separated by rotating the partition plate 107, thereby separating the stratified concrete mixture for subsequent testing. The method of separating the first material cylinder 101 and the second material cylinder 105 by rotating the partition plate 107 is simple in structure and can avoid the problem of material leakage when taking out material after separation. At the same time, a water spray pipe 210 is set in the screening mechanism 2 to wash and screen the stratified concrete mixture, so as to obtain aggregate with fewer impurities and ensure the accuracy of aggregate weighing in the later stage.

[0028] Specifically, by utilizing the first material cylinder 101 and the second material cylinder 105, the concrete mixture is layered without overflowing. The layered concrete can be directly used for density measurement, or each layer can be molded separately to test various properties of the concrete specimens. Using the screening mechanism 2 with water spray pipe 210, the concrete mixture of each layer can be quickly rinsed, removing the paste (excluding aggregate) from the mixture. The cementitious material adhering to the aggregate surface is then cleaned again. After rinsing, the aggregate of each layer is dried, weighed, and sieved, and a sieve curve is plotted.

[0029] In other embodiments, the number of material cylinders may be increased to three, four or more, and corresponding multiple partitions, depending on the experimental requirements.

[0030] Optionally, the first material cylinder 101 is a cylindrical shape without bottoms at both ends, which can be made of steel and has a thickness of about 3-5 mm, and is used to hold concrete mixture. The second material cylinder 105 is a cylindrical shape with a bottom at one end and no bottom at the other end, which can be made of steel and has a thickness of about 3-5 mm, and is used to hold concrete mixture.

[0031] Optionally, at least two ear plates are provided on the first material cylinder 101 and the second material cylinder 105, and the ear plates are provided with connecting holes; the fixing post 110 is a screw, and a first nut 102 is fixed on the screw, and a second nut 111 is detachably provided on the screw; the head of the screw fits into the connecting hole of the second material cylinder 105, and the first nut 102 and the second nut 111 fit into both sides of the connecting hole of the first material cylinder 101.

[0032] Specifically, the outer contour dimensions of the screw head, as well as the outer contour dimensions of the first nut 102 and the second nut 111, are all larger than the inner diameter of the connecting hole. When the first barrel 101 and the second barrel 105 are connected, the fixing post 110 is inserted into the connecting hole, and the first nut 102 and the second nut 111 are used to achieve a detachable connection between the first barrel 101 and the second barrel 105. The structure is simple and the connection stability is good. When the first barrel 101 and the second barrel 105 need to be separated, the second nut 111 is removed from the connecting post 110, and the first barrel 101 can be removed from the second barrel 105. It is understood that the connecting post 110 is provided with threads. Two symmetrical fixing posts 110 can be provided between the first nut 102 and the second nut 111, or the number of fixing posts 110 can be increased according to stability requirements.

[0033] Optionally, a rotating ring 108 is provided on the connecting column 110, and the partition 107 is fixed on the rotating ring 108 by welding or other means; a fixing ring 106 is also provided on the connecting column 110 by welding or bolt connection or other means, and the rotating ring 108 is in contact with the fixing ring 106.

[0034] Specifically, the inner diameter of the rotating ring 108 is larger than the outer diameter of the connecting post 110 to achieve a rotatable connection; or, a bearing is provided between the rotating ring 108 and the connecting post 110 to achieve a rotatable connection. The outer diameter of the fixed ring 106 is larger than the inner diameter of the rotating ring 108 to limit the rotation of the rotating ring 108.

[0035] like Figure 2 As shown, the sealing mechanism includes an annular sealing component 103 and a sealing ring 112 disposed inside the sealing component 103.

[0036] Specifically, the sealing component 103 can be configured as a steel ring or a circular buckle, and can move axially in the first material cylinder 101; the inner wall of the sealing ring 112 can simultaneously adhere to the outer walls of the first material cylinder 101 and the second material cylinder 105 to achieve a seal at the connection between the first material cylinder 101 and the second material cylinder 105, thereby preventing leakage of the concrete mixture.

[0037] In some embodiments, the sealing mechanism is optionally a double-layer sealing ring, which is irregularly trapezoidal in shape. The inner layer is a rubber sealing ring and the outer layer is a steel ring. The two sealing rings are tightly attached to the outer walls of the first material cylinder 101 and the second material cylinder 105, which can also ensure that they can move smoothly up and down in the axial direction of the first material cylinder 101 and the second material cylinder 105, thereby realizing the separation of the two loading chambers of the first material cylinder 101 and the second material cylinder 105 by the partition 107.

[0038] Optionally, the sealing mechanism is mounted on the first material cylinder 101 via a telescopic rod 109. Specifically, the telescopic rod 109 is mounted on the ear plate of the first material cylinder 101, such as a hydraulic telescopic rod, a pneumatic telescopic rod, an electric telescopic rod, or an air column mechanism. The telescopic rod 109 can be used to extend and retract, thereby enabling the sealing mechanism to move smoothly up and down axially between the first material cylinder 101 and the second material cylinder 105.

[0039] When the sealing component 103 is a circular snap fastener, the sealing mechanism can reduce the friction between the sealing ring 112 and the material cylinder by loosening the circular snap fastener when it moves smoothly up and down in the axial direction of the first material cylinder 101 and the second material cylinder 105. When the sealing component 103 is a steel ring, the problem of excessive friction between the sealing ring 112 and the material cylinder can be avoided by limiting the degree of compression on the sealing ring 112.

[0040] Optionally, at least two limiting blocks 104 are provided on the outer wall of the second material cylinder 105. When the sealing mechanism is irregularly trapezoidal in shape, the height of the limiting blocks 104 at different positions in the axial direction of the second material cylinder 105 is different. The limiting blocks 104 are provided to restrict the position of the sealing mechanism and prevent it from moving downwards excessively.

[0041] like Figure 3 As shown, the edge of the partition 107 is beveled to facilitate cutting of the concrete mixture; optionally, the partition 107 is made of steel with a thickness of about 3 to 5 mm, and is generally disc-shaped with an isosceles trapezoidal vertical cross section, requiring it to be flat, smooth and without bending.

[0042] like Figure 4 and Figure 5 As shown, optionally, the sieve 203 is a cylindrical sieve, and a drive shaft 201 is rotatably mounted on the sieve 203. A brush 209 and a water spray pipe 210 are mounted on the drive shaft 201. The water spray pipe 210 in the screening mechanism 2 enables washing and screening of the stratified concrete mixture, resulting in aggregates with fewer impurities and ensuring the accuracy of subsequent aggregate weighing. The mesh size of the sieve 203 can be set to 0.15mm, made of steel mesh, and reinforced with steel bars under the sieve to extend its service life.

[0043] In some embodiments, optionally, the drive shaft 201 can be connected to a drive source such as a motor. When the drive shaft 201 rotates, it can drive the brush 209 to rotate, which can clean the cementitious material adhering to the surface of the aggregate. The rotation of the brush 209 can also be used to disperse the mixture to ensure that the water flow from the high-pressure water spray pipe can fully rinse the concrete mixture. The sieve 203 is provided with a cover plate 202 to prevent the concrete mixture from overflowing during rinsing and brushing. The cover plate 202 can be configured as an operating structure composed of two semicircles, with through holes at the circular parts of the two semicircles to accommodate the drive shaft 201. The cover plate 202 can be made of thin steel plate to prevent the mixture slurry from splashing out under the action of high-pressure water flow.

[0044] The screening mechanism 2 is equipped with a water pump 206 and a motor 205, and buffer pads 204 are provided at both the water pump 206 and the motor 205. Specifically, the water pump 206 is connected to the spray pipe 210 via a pipe to supply water to the spray pipe 210. The spray pipe 210 is equipped with nozzles and other mechanisms, and the spray pipe 210 can be fixed to the inner wall of the sieve 203, such as... Figure 6 and Figure 7As shown, the water spray pipe 210 can also be fixed on the drive shaft 201. In this case, the drive shaft 201 has a hollow pipe in the middle, which is connected to the water spray pipe 210. The water pump 206 is connected to the pipe in the middle of the drive shaft 201 through a water pipe and a rotatable connection. The motor 205 can be set as a vibration motor to provide vibration to the screening mechanism 2.

[0045] The water pump 206 is a high-pressure water pump used to pressurize the water flow and accelerate the washing of the concrete mixture. Both the water pump 206 and the motor 205 are equipped with buffer pads 204 to prevent vibrations from the high-pressure water pump during the non-screening stage from being transmitted to the screen 203, and to prevent excessive vibrations from the motor 205 during the screening stage from being transmitted to the screen 203, thus ensuring operational stability and improving service life. The buffer pads 204 can be implemented using rubber pads or similar materials.

[0046] The water pump 206, the motor 205, and the sieve 203 are all mounted on the base 207; the base 207 provides counterweight for the entire screening mechanism and provides installation space for the high-pressure water pump and the motor 205.

[0047] In some embodiments, a guide channel 208 is also provided on the sieve 203 to guide and discharge the slurry and flushing water that have passed through the sieve.

[0048] The working process or principle of the above embodiments is as follows: like Figure 1 As shown, install the mixture separation mechanism; load the mixed concrete mixture into the first material cylinder 101 and the second material cylinder 105, ensuring that the concrete mixture is flush with the upper edge of the first material cylinder 101.

[0049] The concrete mixture in the first material cylinder 101 and the second material cylinder 105 is left to stand for a preset time, or placed on a conventional vibrating table and vibrated for a preset time.

[0050] Move the sealing mechanism upward so that the connection between the first material cylinder 101 and the second material cylinder 105 is exposed; rotate the partition 107 and slowly cut towards the connection between the first material cylinder 101 and the second material cylinder 105 until the connection between the first material cylinder 101 and the second material cylinder 105 is completely separated.

[0051] Remove the second nut 111 to separate the first material cylinder 101 and the second material cylinder 105.

[0052] The concrete mixture after stratification was poured out, weighed, and the density of each layer was calculated.

[0053] Pour the layered mixture into the sieve 203, cover it with the cover plate 202, and start the water pump 206 to thoroughly rinse the concrete mixture.

[0054] After the slurry in the concrete mixture is rinsed clean, the aggregates remaining from each sieve are removed, dried, and weighed separately.

[0055] Finally, the residual aggregates from each layer are sieved separately, and sieve distribution curves are plotted. Optionally, the sieve distribution curves are plotted by referring to the relevant test requirements of the relevant engineering aggregate test procedures; sieve distribution curves can better reflect the aggregate particle size distribution characteristics of concrete mixtures in different loading chambers.

[0056] The embodiments of the present invention, with the aid of the first material cylinder 101, the second material cylinder 105 and the partition plate 107, can accurately test the segregation resistance of concrete mixtures; in conjunction with the screening mechanism, the degree of stratification of aggregates of different particle sizes in concrete mixtures can be accurately tested, and the test results are reliable and can be used to guide the gradation design of concrete aggregates and subsequent concrete mixture mixing and construction processes; the test device proposed in the embodiments of the present invention is simple, easy to operate and has high practicality.

[0057] It should be noted that the device in the embodiments of the present invention can not only test the settling degree of coarse and heavy aggregates in concrete mixtures, but also test the floating degree of lightweight aggregates in concrete. Although it is a test method and test device for concrete, it can also be used for the segregation resistance test of aggregates in asphalt mixtures and other mixtures if required for testing.

[0058] To improve the separation efficiency and effect of cement slurry with large-sized components such as aggregates and fibers, in some of the following embodiments, a high-efficiency composite dispersion is designed to disperse cement slurry and large-sized components, so as to completely separate cement slurry from aggregates.

[0059] The main component (excluding water) in the dispersion is isopropyltriisostearoyl titanate modified with β-diketone and short-chain methyl ether polyethylene glycol. Isopropyltriisostearoyl titanate acts as a monoalkoxy-type titanate coupling agent, exerting its dispersing effect through an anchored-extended molecular configuration. Its inorganic isopropoxy groups form Ti-OM covalent bonds with the hydroxyl groups on the cement particle surface to achieve anchoring, while the hydrophobic long-chain isostearyl groups extend directionally, constructing a steric barrier to create steric hindrance and weaken particle agglomeration. Simultaneously, it modifies the cement surface and moderately delays hydration, reducing product bridging, thus synergistically achieving stable dispersion. Furthermore, the use of short-chain methyl ether polyethylene glycol enhances the dispersibility of isopropyltriisostearoyl titanate in the aqueous phase while retaining its anchoring ability with the hydroxyl groups on the cement particle surface, forming a stable electric double layer and enhancing electrostatic repulsion. The β-diketone-modified isopropyltriisostearoyl titanate exhibits improved water resistance and hydrolytic stability, extending the dispersion stability period and ensuring the recyclability of the dispersion.

[0060] Polycarboxylate superplasticizers achieve dispersion through a synergistic effect of adsorption, electrostatic repulsion, and steric hindrance. Their polar molecular groups (such as carboxyl groups) adsorb onto the surface of cement and mineral admixture particles, making them negatively charged and generating electrostatic repulsion, thus breaking up initial agglomerates. The non-polar polyether side chains extend in a directional manner, forming a three-dimensional barrier that hinders particle re-agglomeration. Simultaneously, they release encapsulated water, significantly improving slurry fluidity and reducing the water content in the dispersion. Alkylbenzene sulfonate, as an anionic surfactant, has its hydrophilic sulfonic acid groups adsorbed onto cement and mineral admixture particles, while its hydrophobic alkyl chains are oriented at the gas-liquid interface, significantly reducing the surface tension of the cement and mineral admixture slurry and promoting air entrainment during stirring, forming microbubbles. The adsorption layer forms an elastic film, hindering bubble coalescence and rupture, while simultaneously anchoring the bubbles and ensuring uniform dispersion in the slurry, forming a stable closed-pore structure, thereby reducing the viscosity of the dispersion. Polydimethyl diallyl ammonium chloride, as a polymeric flocculant, has ionic groups on its molecular chains that can adsorb charged cement and mineral admixtures in water, neutralizing surface charges to disrupt colloidal stability and promote particle destabilization and aggregation. Simultaneously, the long polymer chains act as adsorption bridging agents, connecting multiple destabilized particles to form large-volume flocs, accelerating floc settling and separation. Combined with the three-stage settling tank 3 of this invention, it ensures the sustainable use of the composite dispersion. Figure 8 As shown, the three-stage settling tank 3 is equipped with an inlet 301 and an outlet 302.

[0061] The preparation process of the composite dispersion is as follows: S101. In a dry four-necked flask, add the measured amount of isopropyl triisostearoyl titanate. Install a stirrer, a condenser (connected to a drying tube), a thermometer, and a constant-pressure dropping funnel. Pour N2 for protection, heat to 80~100℃, and dehydrate under vacuum for 30 minutes with stirring.

[0062] S102. Cool the system to 60-70℃. Dissolve acetylacetone in a small amount of anhydrous toluene according to a molar ratio of Ti:β-diketone = 1:0.8-1.2, and slowly add it dropwise to the flask through a constant pressure dropping funnel, controlling the dropping rate. The addition should be completed in about 1-2 hours. After the addition is complete, continue the reaction at 70-80℃ for 3-5 hours. After the reaction is complete, remove the isopropanol, excess acetylacetone, and solvent generated by the reaction by vacuum distillation at 60℃ under N2 protection to obtain a β-diketone-modified titanate intermediate. S103. Dissolve the intermediate in anhydrous toluene and return it to a dry four-necked flask. Add the catalyst p-toluenesulfonic acid (0.5~1.5 wt%), and weigh out the short-chain methyl ether polyethylene glycol according to a molar ratio of Ti: short-chain methyl ether polyethylene glycol = 1: 0.5~1.5. Dissolve it in anhydrous toluene, and then slowly add it dropwise to the reaction system through a constant-pressure dropping funnel under N2 protection at 100~120℃. Connect a water separator and continuously remove trace amounts of water or small molecule alcohols generated in the reaction by azeotropic mixing with toluene. Reflux the reaction at 110~120℃ for 4~6 hours.

[0063] S104. After the reaction is complete, cool the system to room temperature. Wash the reaction solution with saturated NaHCO3 solution until neutral to remove the catalyst and acidic impurities. Wash several times with deionized water. Separate the organic phase, dry with anhydrous magnesium sulfate, filter, and then remove the toluene solvent by rotary evaporation under reduced pressure at 60-70℃. Remove low-boiling-point residues at 100-120℃ / high vacuum (<1mmHg) for 1-2 hours to obtain a viscous brownish-red to amber liquid, which is the composite modified cement dispersant, with a solid content controlled at 45-55%.

[0064] S105, water: composite modified cement dispersant: polycarboxylate superplasticizer (solid content 30~35%): alkylbenzene sulfonate calcium (powder): polydimethyldiallyl ammonium chloride (powder) are mixed in a mass ratio of 1:0.003~0.008:0.001~0.01:0.0001~0.0015:0.0001~0.0015 in a liquid mixer at low speed (120~180r / min) for 5~10min to obtain a high-efficiency composite dispersion.

[0065] In some embodiments, the mixture separation mechanism 1 includes a first material cylinder 101 and a second material cylinder 105 detachably connected by a fixing column 110, and a sealing mechanism is provided at the connection between the first material cylinder 101 and the second material cylinder 105; a partition plate 107 is rotatably disposed on the fixing column 110 at the location of the sealing mechanism; the screening mechanism 2 includes a sieve 203 and a water spray pipe 210 disposed within the sieve 203. The working process of the above embodiments is as follows: S201, Preparation of High-Efficiency Composite Dispersion: S2011. In a dry four-necked flask, add the measured amount of isopropyl triisostearoyl titanate. Install a stirrer, a condenser (connected to a drying tube), a thermometer, and a constant-pressure dropping funnel. Pour N2 for protection, heat to 90°C, and dehydrate under vacuum for 30 minutes with stirring.

[0066] S2012. Cool the system to 65℃. Dissolve acetylacetone in a small amount of anhydrous toluene according to a Ti:β-diketone ratio of 1:1.1 (molar ratio), and slowly add it dropwise to the flask through a constant-pressure dropping funnel, controlling the dropping rate. The addition should be completed in about 1 hour. After the addition is complete, continue the reaction at 75℃ for 4 hours. After the reaction is complete, remove the isopropanol, excess acetylacetone, and solvent generated by the reaction by vacuum distillation at 60℃ under N2 protection to obtain a β-diketone-modified titanate intermediate. S2013. Dissolve the intermediate in anhydrous toluene and return it to a dry four-necked flask. Add the catalyst p-toluenesulfonic acid (1 wt%) and weigh out the short-chain methyl ether polyethylene glycol according to a molar ratio of Ti: short-chain methyl ether polyethylene glycol = 1:0.5. Dissolve it in anhydrous toluene and slowly add it dropwise to the reaction system through a constant-pressure dropping funnel under N2 protection and at 100°C. Connect a water separator and continuously remove trace amounts of water or small molecule alcohols generated in the reaction by azeotropic mixing with toluene. Reflux the reaction at 110°C for 5 hours.

[0067] S2014. After the reaction is complete, cool the system to room temperature. Wash the reaction solution with saturated NaHCO3 solution until neutral to remove the catalyst and acidic impurities. Wash several times with deionized water. Separate the organic phase, dry with anhydrous magnesium sulfate, filter, and then remove the toluene solvent by rotary evaporation under reduced pressure at 65℃. Remove low-boiling-point residues at 100℃ / high vacuum (<1mmHg) for 1 hour to obtain a viscous brownish-red to amber liquid, which is the composite modified cement dispersant, with a solid content controlled at 50%.

[0068] S2015, water: composite modified cement dispersant: polycarboxylate superplasticizer (solid content 35%): alkylbenzene sulfonate calcium (powder): polydimethyldiallyl ammonium chloride (powder) are mixed in a liquid mixer at a low speed (120 r / min) for 10 min in a mass ratio of 1:0.005:0.001:0.0001:0.0001 to obtain a high-efficiency composite dispersion.

[0069] S202, Separation of aggregates and cement paste: S2021. Weigh three portions of raw materials accurately according to the mixing ratios in Tables 1 and 2, premix each portion for 2 minutes, add water and various additives, and continue stirring for 3 to 5 minutes.

[0070] S2022, such as Figure 1 As shown, the mixture separation mechanism 1 is installed.

[0071] S2023. The mixed concrete mixture is loaded into the first material cylinder 101 and the second material cylinder 105, and the concrete mixture is required to be flush with the upper edge of the first material cylinder 101.

[0072] S2024. Place the concrete mixture in the first material cylinder 101 and the second material cylinder 105 on the vibrating table and vibrate for 30±5s, then remove the device from the vibrating table.

[0073] S2025. Move the sealing mechanism upward so that the connection between the first material cylinder 101 and the second material cylinder 105 is exposed; rotate the partition 107 and slowly cut towards the connection between the first material cylinder 101 and the second material cylinder 105 until the connection between the first material cylinder 101 and the second material cylinder 105 is completely separated.

[0074] S2026. Remove the second nut 111 to separate the first material cylinder 101 and the second material cylinder 105.

[0075] S2027. Weigh the concrete mixture after each layer and calculate the density of each layer. Then, mold concrete flexural and compressive strength test specimens respectively.

[0076] S2028. Clean the first material cylinder 101 and the second material cylinder 105, and repeat steps S2 to S6.

[0077] S2029. Pour the layered mixture into the sieve 203, cover it with the cover plate 202, and start the water pump 206 to thoroughly rinse the concrete mixture.

[0078] S20210. After the slurry in the concrete mixture is washed clean, the aggregates remaining from each layer of the sieve are removed, dried and weighed respectively; finally, the aggregates remaining from each layer of the sieve are screened and the screening data of each grade are counted.

[0079] Table 1 Material proportions (kg / m3) serial number cementing materials gravel Quartz sand water Water reducing agent steel fiber L-1 / 3 1000 259 747 165 20 210 L-2 / 3 1000 259 747 165 20 210 L-3 / 3 1000 259 747 165 20 210 L-6 / 3 1000 259 747 165 20 210 Table 2. Particle size distribution of coarse and fine aggregates (kg / m³) 3 ) Particle size / mm 16.0~19.0 13.2~16.0 9.5~13.2 4.75~9.5 2.36~4.75 1.18~2.36 0.60~1.18 0.03~0.60 0.15~0.03 0.075~0.15 ＜0.075 L-1 / 3 0.00 0.00 0.00 0.00 53.87 42.32 32.86 26.81 21.28 16.89 64.98 L-2 / 3 0.00 0.00 0.00 53.43 42.75 33.59 26.08 21.28 16.89 13.41 51.57 L-3 / 3 0.00 0.00 26.90 47.88 38.31 30.10 23.38 19.07 15.14 12.01 46.22 L-4 / 3 14.42 15.19 23.82 42.41 33.93 26.66 20.70 16.89 13.41 10.64 40.93 Table 3 Comparison of concrete performance under different aggregate particle size distributions

[0080] Table 4. Particle size distribution of coarse and fine aggregates after separation and sieving (kg / m³) 3 )

[0081] Optionally, as shown in Tables 3 and 4, the thickness of the partition 107 is 5mm to 8mm, and the chamfer angle on the edge of the partition 107 is 30°, which is the same as the annular chamfer angle of the sealing assembly. The rotation speed of the partition 107 is 10° / s, which is determined based on test results under different parameters. To control the rotation speed of the partition 107, a drive mechanism 113, such as a motor, can be installed at the partition 107. The rotation speed of the partition 107 can be determined by setting the motor's rotation speed.

[0082] The specific test conditions involved two types of ultra-high performance concrete with coarse aggregate (maximum aggregate sizes of 9.5 mm and 13.2 mm, both with a flow spread of 55 cm ± 3 cm) and high-performance concrete with a maximum aggregate size of 19 mm (slump of 19 cm ± 2 cm) as the test materials. Test scheme: Experimental Group 1: The mixtures in the two cylinders were separated using the device at rotation speeds of 5° / s, 10° / s, 20° / s, and 30° / s, respectively. After separation, the mixtures in both cylinders were allowed to harden naturally within the cylinders. The hardened concrete specimens were then dried at 85°C for 24 hours, and their density was measured. Experimental Group 2: A separate cylinder of the same size without a partition was used, with the same material load as Experimental Group 1. The mixtures were allowed to harden naturally within the cylinder under the same hardening conditions (temperature, humidity, curing time) as Experimental Group 1. The concrete was then divided into two portions according to the dimensions of the two cylinders in Experimental Group 1. The divided specimens were dried at 85°C for 24 hours, and their density was measured.

[0083] Experimental Conclusions: The concrete density test results at different diaphragm rotation speeds are shown in Table 5. The results show that, among the three groups of numbered specimens, the density of the naturally hardened concrete specimen is closest to the density of the specimen after being divided at 10° / s. This demonstrates that at this division speed, the diaphragm separation process has the least impact on the distribution of aggregates in the concrete mixture. Based on the experimental results for different flowabilities and aggregate sizes, the optimal diaphragm separation speed is determined to be 10° / s.

[0084] Table 5 Concrete density at different diaphragm rotation speeds

[0085] Optionally, the rinsing water pressure is 0.5~0.8MPa, and the water flow rate is 15~20L / s. The screening vibration frequency is 147~155 times / min, the amplitude is 8mm~10mm, combined with a planar circular oscillation of 200~230 times / min.

[0086] One embodiment of the present invention also provides an application method for a concrete mixture aggregate anti-segregation performance testing device, which uses the concrete mixture aggregate anti-segregation performance testing device proposed in the embodiment of the present invention, including: placing the mixture separation mechanism on a preset vibration table for vibration, or placing the mixture separation mechanism for a preset time; after the concrete mixture has completed stratification in the first and second material cylinders, removing the sealing mechanism, rotating the partition and inserting it into the connection position of the first and second material cylinders to obtain the stratified concrete mixture; The stratified concrete mixtures were placed into a screening mechanism for washing and screening to obtain aggregates, which were then weighed and tested.

[0087] The present invention also provides a comparative example. The test method of this comparative example adopts the method of the aforementioned embodiments, except that water is used as a dispersant in this comparative example, and no high-efficiency composite dispersion is used. The volume of the dispersion and the time for complete separation of cement paste and aggregate are tested in both methods.

[0088] Table 6. Dispersion dosage and test time under different dispersion media Example Test ratio number Dispersion medium Dispersion dosage / L Test time / min Embodiments of the present invention L-1 / 3 High-efficiency composite dispersion 60 5 Comparative Example L-1 / 3 water 180 43 As shown in Table 6, the test results show that the high-efficiency composite dispersion of the present invention can significantly reduce the amount of dispersion and significantly shorten the test time. Combined with the test results of the above multiple embodiments, it is proved that the test device of the present invention, in conjunction with the high-efficiency composite dispersion, can quickly and accurately test the segregation resistance of aggregates in various types of concrete.

[0089] The above description is merely a preferred embodiment of this practice and is not intended to limit the scope of this practice. Various modifications and variations can be made to this practice by those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this practice should be included within the protection scope of this practice.

Claims

1. A device for testing the anti-segregation performance of aggregates in concrete mixtures, characterized in that, It includes a mixture separation mechanism for stratifying concrete mixtures, and a screening mechanism for rinsing and screening the stratified concrete mixtures. The mixture separation mechanism includes a first material cylinder and a second material cylinder detachably connected by a fixed column. A sealing mechanism is provided at the connection between the first material cylinder and the second material cylinder. A partition is rotatably provided on the fixed column at the location of the sealing mechanism. After the concrete mixture is stratified in the first material cylinder and the second material cylinder, the first material cylinder and the second material cylinder are separated by rotating the partition, thereby realizing the separation of the stratified concrete mixture. The screening mechanism includes a sieve and a water spray pipe disposed inside the sieve, the water spray pipe realizing the rinsing and screening of the stratified concrete mixture.

2. The apparatus for testing the anti-segregation performance of aggregates in concrete mixtures as described in claim 1, characterized in that, At least two ear plates are provided on the first and second material cylinders respectively, and the ear plates are provided with connecting holes; the fixing post is a screw, and a first nut is fixed on the screw and a second nut is detachably provided on the screw; the head of the screw fits into the connecting hole of the second material cylinder, and the first nut and the second nut fit into the two sides of the connecting hole of the first material cylinder respectively.

3. The apparatus for testing the anti-segregation performance of aggregates in concrete mixtures as described in claim 1, characterized in that, A rotating ring is provided on the connecting column, and the partition is fixed on the rotating ring; a fixed ring is also provided on the connecting column, and the rotating ring is in contact with the fixed ring.

4. The apparatus for testing the anti-segregation performance of aggregates in concrete mixtures as described in claim 1, characterized in that, The sealing mechanism includes an annular sealing component and a sealing ring disposed inside the sealing component.

5. The apparatus for testing the anti-segregation performance of aggregates in concrete mixtures as described in claim 1, characterized in that, The sealing mechanism is mounted on the first material cylinder via a telescopic rod.

6. The apparatus for testing the anti-segregation performance of aggregates in concrete mixtures as described in claim 1, characterized in that, The second material cylinder has a limit block on its outer wall; the edge of the partition is beveled; the thickness of the partition is 5mm to 8mm; the chamfer angle on the edge of the partition is 30°; and the rotation speed of the partition is 10° / s.

7. The apparatus for testing the anti-segregation performance of aggregates in concrete mixtures as described in claim 1, characterized in that, The sieve is a cylindrical sieve, and a drive shaft is rotatably mounted on the sieve. A brush and a water spray pipe are mounted on the drive shaft. A water pump and a motor are mounted on the screening mechanism, and buffer pads are provided at both the water pump and the motor.

8. A method for applying a testing device for the anti-segregation performance of aggregates in concrete mixtures, characterized in that, The concrete mixture aggregate segregation resistance testing device as described in any one of claims 1-7 is used, which includes placing the mixture separation mechanism on a preset vibration table for vibration, or placing the mixture separation mechanism for a preset time; after the concrete mixture has completed stratification in the first and second material cylinders, the sealing mechanism is removed, and the partition is rotated and inserted into the connection position between the first and second material cylinders to obtain the stratified concrete mixture. The stratified concrete mixtures were placed into a screening mechanism for washing and screening to obtain aggregates, which were then weighed and tested.

9. The application method of the concrete mixture aggregate anti-segregation performance testing device as described in claim 8, characterized in that, Weigh three portions of raw materials and premix them separately. Add water and admixtures and continue mixing for a preset time. Load the mixed concrete mixture into the first and second material cylinders, ensuring the concrete mixture is flush with the top edge of the first material cylinder. Place the concrete mixture in the first and second material cylinders on a vibrating table and vibrate for 30±5 seconds. Move the sealing mechanism upwards to expose the connection between the first and second material cylinders. Rotate the partition plate tangentially towards the connection between the first and second material cylinders until the connection is completely separated. Separate the first and second material cylinders. Pour out and weigh the separated concrete mixtures, and then mold them into concrete flexural and compressive strength specimens. Clean the first and second material cylinders thoroughly. Pour the separated mixtures into a sieve, cover with a cover, and rinse the concrete mixture thoroughly. After the slurry in the concrete mixture is washed clean, the aggregates remaining from each layer of the sieve are removed, dried, and weighed. Finally, the aggregates remaining from each layer of the sieve are sieved, and the sieve data for each grade are recorded.

10. The application method of the concrete mixture aggregate anti-segregation performance testing device as described in claim 9, characterized in that, Complete separation of cement paste and aggregates is achieved using a composite dispersion, the preparation of which includes: Isopropyl triisostearoyl titanate was added to a four-necked flask; N2 protection was introduced, and the temperature was raised to 90°C. Under stirring, the mixture was dehydrated under vacuum for 30 min; the temperature was lowered to 65°C; acetylacetone was dissolved in anhydrous toluene at a ratio of Ti:β-diketone = 1:1.1, and added dropwise to the flask through a constant pressure dropping funnel. After the addition was complete, the reaction was continued at 75°C for 4 h; after the reaction was completed, isopropanol, excess acetylacetone, and solvent were removed by vacuum distillation at 60°C under N2 protection to obtain a β-diketone-modified titanate intermediate. Dissolve the intermediate in anhydrous toluene and place it back in a dry four-necked flask; add the catalyst p-toluenesulfonic acid, and weigh out short-chain methyl ether polyethylene glycol according to the ratio Ti: short-chain methyl ether polyethylene glycol = 1: 0.5; dissolve it in anhydrous toluene, and then add it dropwise to the reaction mixture through a constant pressure dropping funnel under N2 protection at 100°C; connect a water separator and continuously remove trace amounts of water or molecular alcohol generated in the reaction by toluene azeotropic reaction, and reflux the reaction at 110°C for 5 hours; After the reaction was completed, the mixture was cooled to room temperature. The reaction solution was washed with saturated NaHCO3 solution until neutral to remove the catalyst and acidic impurities. The mixture was then washed with deionized water, dried with anhydrous magnesium sulfate, filtered, and then evaporated under reduced pressure at 65°C to remove the toluene solvent. Low-boiling-point residues were removed at 100°C and under vacuum for 1 hour to obtain a brownish-red to amber liquid. Water, polycarboxylate superplasticizer, calcium alkylbenzene sulfonate, and polydimethyldiallyl ammonium chloride were placed in a liquid mixer at a mass ratio of 1:0.005:0.001:0.0001:0.0001 and mixed at 120 r / min for 10 min to obtain a composite dispersion.

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