A model and method for evaluating uniformity of permeable concrete paste

Abstract

The present invention discloses a model and method for evaluating the uniformity of permeable concrete slurry. The evaluation test model includes a base, a vibration table, and a cubic container with a closed bottom and an open top. The vibration table is fixed on the base, and the cubic container is arranged on the vibration table. The cubic container is composed of an upper shell, a middle shell, and a lower shell that are vertically detachably assembled and connected from top to bottom. During the uniformity evaluation test, the freshly mixed permeable concrete is first loaded into the cubic container in two layers. During each layer loading process, the permeable concrete is evenly rammed from the edge to the center of the cubic container, and the permeable concrete is vibrated to make it dense. The permeable concrete mass of the upper shell, the middle shell, and the lower shell is weighed and calculated respectively, and the uniformity of the permeable concrete is evaluated by the slurry mass. The present invention can accurately, efficiently, and quantitatively evaluate the internal uniformity of the permeable concrete, and ensure that the mechanical strength and permeability of the permeable concrete are coordinated with each other.

Description

Technical Field

[0001] The invention belongs to the technical field of permeable concrete working performance testing, and in particular relates to a permeable concrete slurry uniformity evaluation model and evaluation method. Background Art

[0002] Pervious concrete is a porous, eco-friendly, permeable material made by mixing aggregate, sand (little or no), cement and water, admixtures and admixtures. It is of great significance to groundwater recharge, promote vegetation growth, maintain ecological balance and alleviate urban heat island effect. Due to the characteristics of high porosity, small amount of slurry and low slump of pervious concrete, the type of vibration equipment and vibration time have an important influence on the distribution of slurry inside the material. If the vibration table is used for too long, due to the high aggregate content and large internal porosity, the aggregates are prone to interlocking, and the slurry migrates downward under the action of the exciting force, resulting in the slurry gathering at the bottom of the specimen, while the upper slurry is insufficient, which has an adverse effect on the strength and permeability coefficient of the pervious concrete specimen. At the same time, due to the action of external forces such as bumps and vibrations during construction and transportation, the newly mixed pervious concrete is prone to slurry and aggregate stratification. The unevenness of the material makes it difficult for the mechanical properties and permeability of the newly mixed pervious concrete to meet the expected requirements after hardening. It can be seen that the uniformity of permeable concrete slurry distribution is crucial to material mix design, construction quality control and service performance.

[0003] Therefore, accurate and rapid evaluation of the uniformity of permeable concrete paste is an important prerequisite for coordinating its mechanical and permeable properties. At present, domestic and foreign scholars have used qualitative methods such as "hand-grabbing into a ball", comprehensive consistency index, porosity uniformity and paste quality to evaluate the working performance of freshly mixed permeable concrete. The name of a Chinese patent is: A device and method for testing the workability of freshly mixed permeable concrete, and the application number is: 201710965302.6. This patent discloses quantitative evaluation of the workability of permeable concrete by quantitatively testing the porosity difference between the upper and lower layers of permeable concrete after vibration through image processing technology. The non-uniformity of porosity can reflect the workability of the material, but the interface obtained is limited and lacks representativeness. Another Chinese patent is titled: A test device and method for evaluating the working performance of permeable concrete, with application number: CN201611231212.6. The patent discloses that after the freshly mixed permeable concrete is vibrated, the mass of the slurry passing through the grid is weighed to evaluate the working performance of the permeable concrete. The slurry mass, as a comprehensive indicator, can better characterize the working properties of the material. Under the coupling of its own gravity and external excitation force, the slurry flow has a certain orientation. Therefore, weighing the slurry mass passing through the grid can only evaluate the flow of the slurry at the bottom of the material, but cannot reveal the differences in the distribution of the slurry at other positions inside the material, and it is difficult to objectively reflect the non-uniformity of the freshly mixed permeable concrete. Summary of the invention

[0004] The purpose of the present invention is to provide a model and method for evaluating the uniformity of permeable concrete paste. The present invention can effectively solve the problem of lack of representativeness of evaluation indicators and evaluation of the uniformity of permeable concrete by the paste quality of local areas, thereby revealing the differences in the distribution of concrete paste in other positions inside the material, achieving a scientific, accurate, quantitative and rapid evaluation of the distribution uniformity of paste at different positions of the material, and realizing the coordination of its mechanical properties and permeability function. . In order to achieve the above purpose, the present invention adopts the following technical solutions:

[0005] According to one aspect of the present invention, a permeable concrete slurry uniformity evaluation model is provided, the evaluation test device comprises a base, a vibration table and a cubic container with a closed bottom and an open top, the vibration table is fixed on the base, and the cubic container is arranged on the vibration table; the cubic container consists of an upper shell, a middle shell and a lower shell that are vertically detachably assembled and connected from top to bottom, the bottom end of the lower shell is closed and the top end is open, connecting ears are respectively arranged on the surrounding outer walls of the upper shell, the surrounding outer walls of the middle shell and the surrounding outer walls of the lower shell, and the outer walls of the adjacent upper shell and the outer walls of the middle shell, as well as the outer walls of the adjacent middle shell and the outer walls of the lower shell, are respectively connected to each other by connecting ears and bolts.

[0006] The above scheme is further preferred, in that the inner walls of the upper opening of the lower shell and the upper opening of the middle shell are provided with supporting steps, and the lower opening of the middle shell and the lower opening of the upper shell are respectively provided with plug-in parts which shrink toward the inside of the shell, the plug-in part of the lower opening of the middle shell is plugged into the supporting step of the upper opening of the lower shell, and the plug-in part of the lower opening of the upper shell is plugged into the supporting step of the upper opening of the middle shell.

[0007] The above scheme is further preferred that the outer wall of the upper opening of the lower shell and the outer wall of the lower opening of the middle shell, as well as the outer wall of the upper opening of the middle shell and the outer wall of the lower opening of the upper shell are connected to each other through connecting ears and bolts.

[0008] The above scheme is further preferred that the inner length and inner width of the upper shell body, the middle shell body and the lower shell body are 150mm-180mm; the height of the upper shell body, the middle shell body and the lower shell body are 50mm-80mm; the thickness of the upper shell body, the middle shell body and the lower shell body is not less than 5mm.

[0009] The above scheme is further preferred that a container cover body is provided at the upper opening portion of the upper shell body, and the outer wall of the container cover body is connected to the outer wall of the upper shell body by a snap; the container cover includes an outer cover body, an annular support platform arranged on the inner wall of the outer cover body, and a pressure-bearing block body slidably arranged between the top end of the inner wall of the outer cover body and the annular support platform, a buffer cavity is formed between the top end of the pressure-bearing block body and the top end of the inner wall of the outer cover body, the pressure-bearing block body is matched and inserted into the inner wall of the upper opening of the upper shell body, and the inner wall of the outer cover body is matched and sleeved on the outer wall of the upper opening of the upper shell body.

[0010] The above solution is further preferred in that an elastic component is arranged in the buffer cavity, and the top of the pressure-bearing block is connected to the top of the inner wall of the outer cover through the elastic component.

[0011] The above scheme is further preferred in that a rotating table is arranged on the base, and the vibration table is fixed to the base via the rotating table.

[0012] According to another aspect of the present invention, the present invention provides an evaluation method for a uniformity evaluation model of a permeable concrete paste, comprising the following steps:

[0013] Step 1: Load the freshly mixed permeable concrete slurry into a cubic container formed by an upper shell, a middle shell and a lower shell in two layers, and evenly tamp from the edge to the center of the cubic container 10 to 20 times during each layer loading process;

[0014] Step 2: Place the cubic container on a vibration table, cover the container cover and fasten it to the outer wall of the cubic container, so that the pressure-bearing block contacts the concrete slurry, start the vibration table to vibrate to make the permeable concrete slurry dense, and the vibration time lasts for 120s-180s. Remove the container cover and smooth its surface. Before the permeable concrete slurry is initially solidified, remove the bolts assembling the outer walls of the upper shell, the middle shell and the lower shell in turn. When each shell is removed, cut off the permeable concrete slurry generated in the upper shell, the middle shell and the lower shell, and then weigh the mass of the permeable concrete slurry generated in the upper shell, the middle shell and the lower shell respectively.

[0015] Step 3: After weighing, rinse and screen, weigh the saturated dry mass of aggregate and / or sand contained in the permeable concrete paste again and measure the corresponding surface area, and evaluate the uniformity of the permeable concrete by the mass of the permeable concrete paste.

[0016] The above scheme is further preferred, that in the step three, the nominal particle size of the aggregate used in the permeable concrete is 2.36mm~19.5mm; the sieve hole size of the screening is 0.15mm~2.36mm; in the step two, during the vibration of the vibration table, the rotating table is also started to drive the cubic container to rotate centrifugally, and the container cover is buckled on the outer wall of the cubic container, and the pressure-bearing block is in contact with the concrete slurry during the vibration and centrifugal rotation process, so that the permeable concrete slurry is made denser, and the container cover is removed after the vibration is completed.

[0017] The above scheme is further preferred, the masses of the permeable concrete slurry generated in the upper shell 1, the middle shell and the lower shell are weighed to be M and 1 、M 2 and M 3 , weigh the saturated surface dry mass of aggregate and / or sand contained in the permeable concrete paste as W 1 , W 2 and W 3 The surface areas are S 1 , S 2 and S 3 , then the uniformity of the permeable concrete slurry generated in the upper shell, middle shell and lower shell satisfies:

[0018]

[0019]

[0020]

[0021] The overall uniformity U of the permeable concrete paste satisfies the sum of the uniformities of each permeable concrete paste, that is, the overall uniformity U satisfies: U = U 1 +U 2 +U 3 The smaller the overall uniformity U, the better the uniformity of the permeable concrete paste.

[0022] In summary, since the present invention adopts the above technical solution, the present invention has the following technical effects:

[0023] The present invention proposes an accurate, efficient and quantitative permeable concrete uniformity evaluation method characterized by aggregate surface area, slurry quality and its airspace distribution by testing the quality of permeable concrete slurry in different areas of the upper shell, middle shell and lower shell of a cubic container, thereby effectively solving the problems of lack of representativeness of evaluation indicators and evaluation of permeable concrete uniformity by slurry quality in local areas, thereby revealing the differences in the distribution of concrete slurry in other positions inside the material, and objectively reflecting the uniformity of freshly mixed permeable concrete; the present invention achieves scientific, accurate, quantitative and rapid evaluation of the distribution uniformity of slurry in different positions of the material, and realizes the coordination of its mechanical properties and permeability function. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a structural schematic diagram of a permeable concrete paste uniformity evaluation model of the present invention;

[0025] Figure 2 It is a schematic diagram of the appearance structure of the cubic container of the present invention;

[0026] Figure 3 It is a schematic diagram of the internal structure of the cubic container of the present invention;

[0027] Figure 4 is a top view of a cubic container of the present invention;

[0028] Figure 5 It is a structural schematic diagram of the container cover of the present invention. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and preferred embodiments. However, it should be noted that many details listed in the specification are only for the purpose of enabling the reader to have a thorough understanding of one or more aspects of the present invention, and these aspects of the present invention can be implemented even without these specific details.

[0030] Embodiment 1 This embodiment provides a method for evaluating the uniformity of permeable concrete paste, which specifically includes the following method:

[0031] (I) Make a uniformity evaluation model, combined with Figure 1 and Figure 2As shown, the evaluation model includes a base 10, a vibration table 11 and a cubic container 100 with a closed bottom and an open top, the vibration table 11 is fixed on the base 10, and the cubic container 10 is arranged on the vibration table 11. In the present invention, a rotating table 13 can also be arranged on the base 10, and the vibration table 11 is fixed to the base 10 through the rotating table 13; thereby facilitating the vibration and tamping of the concrete slurry, accelerating the distribution speed of the concrete slurry at different positions in different material shells and the difference in distribution at different positions, thereby improving the efficiency of concrete uniformity evaluation.

[0032] Combination Figure 2 , Figure 3 and Figure 4 As shown, the cubic container 100 is vertically detachably assembled and connected from top to bottom in the form of an upper shell 1, a middle shell 2 and a lower shell 3, the bottom end of the lower shell 3 is closed and the top end is open, and connecting ears 101 are respectively arranged on the surrounding outer walls of the upper shell 1, the surrounding outer walls of the middle shell 2 and the surrounding outer walls of the lower shell 3, and the outer walls of the adjacent upper shell 1 and the outer walls of the middle shell 2 and the outer walls of the adjacent middle shell 2 and the outer walls of the lower shell 3 are respectively connected to each other through connecting ears 101 and bolts 102; 4 symmetrical connecting ears 101 are arranged on the surrounding side walls of the bottom of each shell, and the connecting ears 101 are steel sheets with holes, and the steel sheets are distributed in the same manner; screw holes 101a are arranged on the connecting ears 101, and the specifications of the bolts 102 are GB70-85M5×20, and the connection between the upper shell 1 and the middle shell 2 and between the middle shell 2 and the lower After the connecting ears 101 on the shells 3 are aligned with each other, the bolts 102 are inserted into the screw holes 101a to fix the adjacent shells together; the outer wall of the upper opening of the lower shell 3 and the outer wall of the lower opening of the middle shell 2, as well as the outer wall of the upper opening of the middle shell 2 and the outer wall of the lower opening of the upper shell 1 are connected to each other through the connecting ears 101 and the bolts 102, so that the cubic container 100 can be quickly installed and disassembled to achieve rapid preparation of each layer of concrete slurry; the inner length and inner width of the upper shell 1, the middle shell 2 and the lower shell 3 are 150mm to 180mm; the inner length and inner width of the upper, middle and lower parts are 150mm, and the height is 50mm to 80mm; the thickness of the upper shell 1, the middle shell 2 and the lower shell 3 is not less than 5mm;

[0033] In the present invention, combined with Figure 2 , Figure 3 and Figure 4As shown, a support step 10a is provided on the inner wall of the upper opening of the lower shell 3 and the upper opening of the middle shell 2, and an inserting portion 10b that shrinks toward the inside of the shell is respectively provided on the lower opening of the middle shell 2 and the lower opening of the upper shell 1, the inserting portion of the lower opening of the middle shell 2 is inserted into the support step of the upper opening of the lower shell 3, and the inserting portion 10b of the lower opening of the upper shell 1 is inserted into the support step 10a of the upper opening of the middle shell 2; when installing and fixing the upper shell 1, the middle shell 2 and the lower shell 3, the adjacent shells are inserted through the support steps 10a and the inserting portion 10b, so that the inner wall of each adjacent shell is flush with the outside, and a good limiting effect is formed between the adjacent shells, and when the bolts 102 are used to fix the connecting ears 101 of the outer walls around the upper shell 1, the middle shell 2 and the lower shell 3, the adjacent shells are prevented from being misaligned, and the slurry is reduced from leaking out of the connection between the adjacent shells when mixing the concrete slurry.

[0034] In the present invention, if Figure 1 and Figure 5 As shown, a container cover 12 is provided at the upper opening of the upper shell 1, and the outer wall of the container cover 12 is connected to the outer wall of the upper shell 1 by a snap buckle, so that the container cover 12 can be easily disassembled to load the permeable concrete slurry; the container cover 12 includes an outer cover 120, an annular support platform 121 arranged on the inner wall of the outer cover 120, and a pressure-bearing block 122 slidably arranged between the top end of the inner wall of the outer cover 120 and the annular support platform 121, a buffer cavity 123 is formed between the top end of the pressure-bearing block 122 and the top end of the inner wall of the outer cover 120, the pressure-bearing block 122 is matched and inserted into the inner wall of the upper opening of the upper shell 1, and the inner wall of the outer cover 120 is matched and sleeved on the upper shell 1 The outer wall of the upper opening; an elastic component 124 is arranged in the buffer cavity 123, and the top of the pressure-bearing block 122 is connected to the top of the inner wall of the outer cover body 120 through the elastic component 124. The elastic component 124 is a shock-absorbing spring. During the vibration and centrifugal rotation, the slurry in the cubic container 100 is prevented from leaking out. The pressure-bearing block 122 can beat the concrete slurry during the up and down buffering movement, making the permeable concrete slurry more compact, and to a certain extent simulates the force generated when the concrete surface is vibrated on site, so that the indoor test is closer to the actual vibration.

[0035] (II) Implement slurry uniformity evaluation

[0036] (1) Preparation of permeable concrete paste samples:

[0037] 10-20 mm aggregate, PO 42.5 cement, tap water, and polycarboxylate water reducer are mixed according to the mix ratio in Table 1; the uniformity evaluation test device prepared in the above step (i) is used as a test mold, and the freshly mixed permeable concrete slurry is first loaded into a cubic container 100 formed by an upper shell 1, a middle shell 2, and a lower shell 3 in two layers, and a stirring rod is used to evenly tamp from the edge to the center of the cubic container 100 10 to 20 times during each layer loading process;

[0038] Table 1: Water-permeable concrete mix ratio

[0039]

[0040] (2) Weigh and calculate the mass of permeable concrete paste

[0041] After the concrete slurry is inserted and tamped evenly, the test mold (cubic container 100) filled with the freshly mixed permeable concrete slurry is placed on the vibration table 11, and the container cover 12 is covered and fastened to the outer wall of the test mold (cubic container 100), so that the pressure-bearing block 122 is in contact with the concrete slurry, and the vibration table 11 is started to vibrate to make the permeable concrete slurry dense. The vibration time lasts for 180 seconds, and the container cover 12 is removed and its surface is smoothed. During the vibration of the vibration table 11, the rotating table 13 can also be started to drive the cubic container 100 to rotate centrifugally, and the container cover 12 can be fastened to the outer wall of the test mold (cubic container 100). The wall, the pressure-bearing block 122 is in contact with the concrete slurry during vibration and centrifugal rotation, so that the permeable concrete slurry is more compact. After the vibration is completed, the container cover 12 is removed; before the permeable concrete slurry is initially solidified, the bolts 102 assembled on the outer walls of the upper shell 1, the middle shell 2 and the lower shell 3 of the test mold are removed in sequence. When each shell is removed, the permeable concrete slurry generated in the upper shell 1, the middle shell 2 and the lower shell 3 is cut off in sequence, and then the mass of the permeable concrete slurry generated in the upper shell 1, the middle shell 2 and the lower shell 3 is weighed respectively. The mass of the permeable concrete slurry generated in the upper shell 1, the middle shell 2 and the lower shell 3 is recorded as M 1 、M 2 and M 3 ;

[0042] (3) Weighing and calculating the mass and surface area of ​​aggregates: before the initial setting of the permeable concrete slurry, the permeable concrete slurry weighed above is rinsed and screened to obtain relatively clean aggregates and / or sands of the permeable concrete slurry. The aggregates are rinsed to ensure that their surfaces are not covered by the slurry; then, various levels of sieve holes with a nominal aggregate particle size of 2.36 mm to 19.5 mm are selected for screening, and the sieve hole size of the screening is 0.15 mm to 2.36 mm; the sieve hole size of the screening is related to the composition characteristics of the permeable concrete. When the permeable concrete to be evaluated contains a certain amount of sand, the minimum sieve hole size is 0.15 mm, when the permeable concrete to be evaluated does not contain sand, the minimum sieve hole size is 2.36 mm, and the nominal maximum particle size of the aggregate used is less than 19.5 mm; the saturated surface dry mass of the aggregate and / or sand contained in the permeable concrete slurry is weighed again and the corresponding surface area is measured. After statistics, weighing and calculation, the saturated surface dry mass of the aggregate and / or sand contained in the permeable concrete slurry of the upper shell 1, the middle shell 2 and the lower shell 3 is finally obtained as W 1 , W 2 and W 3 The aggregate surface areas of permeable concrete paste are S 1 , S 2 and S 3 , thus evaluating the uniformity of permeable concrete by the quality of permeable concrete paste.

[0043] (4) Calculation of uniformity of permeable concrete paste

[0044] According to the above step (2), the mass of the permeable concrete slurry generated in the upper shell 1, the middle shell 2 and the lower shell 3 is respectively recorded as M 1 、M 2 and M 3 , and the saturated surface dry mass of aggregate and / or sand contained in the permeable concrete slurry of the upper shell 1, the middle shell 2 and the lower shell 3 in the above step (3) is W respectively 1 , W 2 and W 3 The surface areas are S 1 , S 2 and S 3 , the uniformity calculation of permeable concrete paste meets the following requirements:

[0045]

[0046]

[0047]

[0048] The overall uniformity U of the permeable concrete paste satisfies the sum of the uniformities of each permeable concrete paste, that is, the overall uniformity U satisfies: U = U1 +U 2 +U 3 The smaller the overall uniformity U, the better the uniformity of the permeable concrete paste. Through the above simulation experiment, the values ​​of the permeable concrete mass, aggregate mass and surface area are substituted into the formula, and the overall uniformity of the permeable concrete is finally calculated to be U = 0.82

[0049] Example 2

[0050] In this example, the vibration table 11 is used for a vibration time of 120 seconds, and the other technical features are the same as those of Example 1. It is calculated that the overall uniformity of the permeable concrete is U=0.54.

[0051] (III) Verification of strength and water permeability

[0052] Permeable concrete samples were prepared according to the vibration parameters and vibration methods used in Example 1, and 7d compressive strength and permeability coefficient tests were performed. The test results are shown in Table 2.

[0053] Table 2: Permeable concrete paste strength and permeability

[0054] Example No. 7d compressive strength (MPa) Water permeability coefficient (mm / s) Example 1 5.4 2.35 Example 2 8.2 4.11

[0055] As can be seen from Table 2, the strength and water permeability of Example 1 are worse than those of Example 2; according to the calculation results of the overall uniformity, the uniformity calculated for Example 1 is U=0.82; the uniformity calculated for Example 2 is U=0.54, and the results show that the uniformity of Example 2 is better than that of Example 1. Since the vibration time of Example 1 is 180s, which is too long, the uniformity of the permeable concrete slurry inside the specimen is poor, while the vibration time of Example 2 is more appropriate, and the slurry uniformity is better. It can be seen that the uniformity evaluation of the permeable concrete slurry proposed in the present invention is effective and feasible, and can scientifically, accurately, quantitatively and quickly evaluate the distribution uniformity of the slurry at different positions of the material, thereby achieving the coordination of its mechanical properties and water permeability function.

[0056] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for evaluating uniformity of permeable concrete paste, characterized in that: The evaluation test model adopted includes a base, a vibration table and a cubic container with a closed bottom and an open top, the vibration table is fixed on the base, and the cubic container is arranged on the vibration table; the cubic container is composed of an upper shell, a middle shell and a lower shell which are vertically detachably assembled and connected from top to bottom, the bottom end of the lower shell is closed and the top end is open, and connecting ears are respectively arranged on the surrounding outer walls of the upper shell, the surrounding outer walls of the middle shell and the surrounding outer walls of the lower shell, and the outer walls of the adjacent upper shell and the middle shell, and the outer walls of the adjacent middle shell and the lower shell They are connected to each other by connecting ears and bolts respectively, support steps are provided on the inner walls of the upper end opening of the lower shell and the upper end opening of the middle shell, and plug-in parts that shrink toward the inside of the shell are provided on the lower end opening of the middle shell and the lower end opening of the upper shell respectively, the plug-in part of the lower end opening of the middle shell is plugged into the support step of the upper end opening of the lower shell, and the plug-in part of the lower end opening of the upper shell is plugged into the support step of the upper end opening of the middle shell, and a container cover is provided on the upper opening of the upper shell, and the outer wall of the container cover is connected to the outer wall of the upper shell by snap fasteners; The evaluation method includes the following steps: Step 1: Load the freshly mixed permeable concrete slurry into a cubic container formed by an upper shell, a middle shell and a lower shell in two layers, and evenly tamp from the edge to the center of the cubic container 10 to 20 times during each layer loading process; Step 2: Place the cubic container on a vibration table, cover the container cover and fasten it to the outer wall of the cubic container, so that the pressure-bearing block contacts the concrete slurry, start the vibration table to vibrate to make the permeable concrete slurry dense, and the vibration time lasts for 120s-180s. Remove the container cover and smooth its surface. Before the permeable concrete slurry is initially solidified, remove the bolts assembling the outer walls of the upper shell, the middle shell and the lower shell in turn. When each shell is removed, cut off the permeable concrete slurry generated in the upper shell, the middle shell and the lower shell, and then weigh the mass of the permeable concrete slurry generated in the upper shell, the middle shell and the lower shell respectively. Step 3: After weighing, rinse and screen, weigh the saturated dry mass of aggregate and / or sand contained in the permeable concrete paste again and measure the corresponding surface area, and evaluate the uniformity of the permeable concrete by the mass of the permeable concrete paste; The masses of the permeable concrete slurry generated in the upper shell, the middle shell and the lower shell are weighed as M1, M2 and M3 respectively, the saturated surface dry masses of the aggregate and / or sand contained in the permeable concrete slurry are weighed as W1, W2 and W3 respectively, and the surface areas are weighed as S1, S2 and S3 respectively, then the uniformity of the permeable concrete slurry generated in the upper shell, the middle shell and the lower shell satisfies: The overall uniformity U of the permeable concrete paste satisfies the sum of the uniformities of each permeable concrete paste, that is, the overall uniformity U satisfies: U=U1+U2+U3. The smaller the overall uniformity U is, the better the uniformity of the permeable concrete paste is.

2. A method for evaluating uniformity of permeable concrete paste according to claim 1, characterized in that: The inner length and inner width of the upper shell, the middle shell and the lower shell are 150mm to 180mm; the height of the upper shell, the middle shell and the lower shell are 50mm to 80mm; the thickness of the upper shell, the middle shell and the lower shell is not less than 5mm.

3. A method for evaluating uniformity of permeable concrete paste according to claim 1, characterized in that: The container cover body includes an outer cover body, an annular support platform arranged on the inner wall of the outer cover body, and a pressure-bearing block body slidably arranged between the top end of the inner wall of the outer cover body and the annular support platform, a buffer cavity is formed between the top end of the pressure-bearing block body and the top end of the inner wall of the outer cover body, the pressure-bearing block body is matched and inserted into the inner wall of the opening on the upper shell body, and the inner wall of the outer cover body is matched and sleeved on the outer wall of the opening on the upper shell body.

4. A method for evaluating uniformity of permeable concrete paste according to claim 3, characterized in that: An elastic component is arranged in the buffer cavity, and the top of the pressure-bearing block is connected to the top of the inner wall of the outer cover through the elastic component.

5. The method for evaluating uniformity of permeable concrete paste according to claim 1, characterized in that: A rotating table is arranged on the base, and the vibration table is fixed on the base through the rotating table.

6. A method for evaluating uniformity of permeable concrete paste according to claim 1, characterized in that: In the step three, the nominal particle size of the aggregate used in the permeable concrete is 2.36mm~19.5mm; the sieve hole size of the screening is 0.15mm~2.36mm; in the step two, during the vibration of the vibration table, the rotating table is also started to drive the cubic container to rotate centrifugally, and the container cover is buckled on the outer wall of the cubic container. During the contact vibration and centrifugal rotation of the pressure-bearing block and the concrete slurry, the permeable concrete slurry is made denser. After the vibration is completed, the container cover is removed.

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