A concrete test model and durability test method for a salinized soil erosion environment

Abstract

The application relates to the technical field of concrete testing, in particular to a concrete test mold for a salinization soil erosion environment and a durability test method, which comprises a concrete test mold, a mold pressing device and a support, the mold pressing device is connected below the support through a lifting driving element, the concrete test mold is directly below the mold pressing device, the concrete test mold is composed of a test mold frame and a movable partition plate, and the movable partition plate cooperates with the test mold frame to form concrete forming areas and salinization soil forming areas with different sizes. The application adjusts the position combination of the key grooves where the movable partition plate is located to form different test mold sizes, is more flexible and convenient to adjust compared with the existing size-adjustable test mold, and mainly relies on the key grooves arranged on the test mold frame and the movable partition plate for assembling and disassembling the test mold, is simpler to operate compared with the traditional fixed bolt operation, and has higher forming test piece precision.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of concrete test, in particular to a concrete test mold for salinized soil erosion environment and a durability test method. BACKGROUND

[0002] Due to the influence of climate and human agricultural activities, there are usually large areas of salinized soil in arid and semiarid regions. The surface part of the hydraulic concrete structure built in this region is usually subjected to the erosion of salt solution, dry-wet cycle and freeze-thaw cycle, etc. However, the hydraulic concrete structure below the surface is subjected to the erosion of salinized soil. The salt ions (chloride ions, sulfate ions, sodium ions, calcium ions, etc.) in the salinized soil may erode the concrete structure with the movement of water in the soil, which can also cause problems such as durability reduction of concrete material and steel corrosion.

[0003] Traditional concrete durability is usually studied by indoor accelerated degradation test, such as concrete salt erosion test, dry-wet cycle test and freeze-thaw cycle test, etc. The prepared target concrete test block is usually placed in a salt erosion solution, a dry-wet cycle machine and a freeze-thaw cycle machine. Such test method can only study the durability of concrete subjected to water or salt solution erosion. The solid erosion material such as salinized soil is easy to collapse under this experimental condition. At present, there is a lack of test mold and test method for the durability of concrete material subjected to the action of salinized soil wrapping and complex erosion environment. Therefore, it is difficult to carry out concrete durability test under the condition of solid erosion material such as salinized soil.

[0004] In order to carry out the durability test research of concrete in the salinization soil erosion environment, the concrete test block needs to be placed in the salinization soil erosion environment, and the salinization soil erosion environment includes the salinization soil constant-temperature and constant-humidity environment, dry-wet cycle, freeze-thaw cycle, dry-wet-freeze-thaw cycle and the like. The target concrete test block needs to be made in advance through the concrete test mold for the durability test of concrete. The traditional concrete test mold mainly includes a cubic test mold, a cuboid test mold and a cylindrical test mold. For example, a combined concrete test mold disclosed in a patent with the authorization number CN 220661257 U is combined by a supporting bottom plate, an integrally fixed side plate and a mutually lockable partition plate, which simplifies the difficulty of brushing demolding agent and cleaning, and can complete the molding of multiple test blocks at a time through the type of mutually lockable partition plate combination, which is beneficial to batch operation. However, the current concrete test mold can only make concrete test blocks of different sizes, and there is no space or facility around the test piece after demolding for attaching and fixing the granular erosion medium such as salinization soil, which cannot create a salinization soil erosion environment with different compactness, water content or salt content in the laboratory. There is a certain difference between the test environment and the actual environment, which cannot accurately study the durability of concrete materials in the salinization soil erosion, dry-wet cycle, freeze-thaw cycle, dry-wet-freeze-thaw cycle and the like, and there are defects and deficiencies in the research on the erosion of concrete in the salinization soil environment. SUMMARY

[0005] In view of the above-mentioned defects and problems, the present application provides a concrete test mold for salinization soil erosion environment and a durability test method, which innovatively designs a concrete test mold capable of creating a salinization soil erosion environment and a concrete durability test method cooperating with existing ovens, freeze-thaw cycle machines and other equipment, so as to realize the purpose of durability test research of concrete materials under the erosion of salinization soil.

[0006] The technical problem of the present application is solved by the following solution: a concrete test mold for salinization soil erosion environment, comprising a concrete test mold, a mold pressing device and a support, the mold pressing device is connected below the support through a lifting driving part, and the concrete test mold is directly below the mold pressing device, the concrete test mold is composed of a test mold frame and a movable partition plate, wherein the movable partition plate includes a set of longitudinal partition plates, a set of transverse partition plates and a horizontal partition plate, a plurality of key grooves are formed in the inner walls of the test mold frame and the movable partition plate in the transverse and longitudinal directions, the longitudinal partition plates, the transverse partition plates and the horizontal partition plate can be clamped in the key grooves, and cooperate with the test mold frame to form different sizes of concrete molding area and salinization soil molding area;

[0007] The compression molding device comprises a compression molding group, which is composed of a large compression molding body, a medium compression molding body and a small compression molding body, which are sequentially sleeved, and the sizes of the compression molding bodies are matched with the surface size of the salinization soil forming area, and are used for balancing the static pressure in the salinization soil forming process, and a compression column group is vertically arranged above each compression molding body, each compression column of the compression column group is sequentially sleeved, and each compression column is connected through a limiting bolt, and the outermost large compression column is connected below the bracket through a lifting driving element;

[0008] The internal structures of the large compression molding body, the medium compression molding body and the small compression molding body are the same, which are hollow structures, and a water permeable plate is arranged in the compression molding body, the water permeable plate divides the compression molding body into a water storage cavity and a compression groove from top to bottom, a compression plate is detachably arranged in the compression groove, and the compression plates at the bottoms of the compression molding bodies are at the same horizontal plane in the initial state.

[0009] Further, the test mold frame is composed of two same-size isosceles right triangles, which can be combined to form a square test mold frame, a plurality of horizontal key grooves and vertical key grooves are arranged on the inner wall of the test mold frame, the key groove width is matched with the thickness of the partition plate, the horizontal key grooves on the test mold frame are used for fixing and adjusting the position of the horizontal partition plate, and the vertical key grooves are used for fixing and adjusting the position of the longitudinal partition plate, the inner wall of the longitudinal partition plate is also provided with a vertical key groove, which is used for fixing and adjusting the position of the transverse partition plate.

[0010] Further, the movable partition plate can cooperate with the test mold frame to form three different sizes of salinization soil forming areas, which are a large forming area, a medium forming area and a small forming area, and the concrete forming area adaptively changes according to the size of the salinization soil forming area.

[0011] Further, a large compression column, a medium compression column and a small compression column are vertically arranged above the large compression molding body, the medium compression molding body and the small compression molding body respectively, the small compression column is longitudinally movably sleeved in the medium compression column, the medium compression column is longitudinally movably sleeved in the large compression column, and a limiting ring is arranged in the medium compression column and the large compression column, which is used for limiting the compression column inside.

[0012] Further, mounting screw holes are formed on the water permeable plate, mounting bolts are rotatably sleeved on the compression plate, and the compression plate is mounted in the compression groove of the compression molding body through the mounting bolts.

[0013] Further, bolt fixing holes are arranged at the interfaces of the two isosceles right triangles of the test mold frame, which are used for fixing the test mold frame.

[0014] Further, a water inlet is formed on each compression molding body and communicates with the water storage cavity, and an operation notch is formed on the large compression molding body and the medium compression molding body, so that the water inlet on the internal compression molding body is exposed.

[0015] A kind of durability test method for salinization soil erosion environment, comprising the following steps:

[0016] S1, by fixed bolt, two isosceles right triangle frames are butted to form a square test mold frame, during the butt joint process, the horizontal partition in movable partition is embedded in the horizontal key groove of test mold frame;

[0017] S2, 1 group of two longitudinal partitions is embedded in the vertical key groove on the test mold frame, and the bottom of the longitudinal partition is embedded in the horizontal key groove on the horizontal partition;

[0018] S3, 1 group of two transverse partitions is embedded in the vertical key groove on the longitudinal partition, at this time, the area surrounded by the horizontal partition, longitudinal partition and transverse partition is the concrete test piece forming area;The external area is the salinization soil forming area;

[0019] S4, the target concrete after stirring is filled into the concrete test piece forming area, and after vibrating, troweling, initial setting, demolding, standard curing chamber curing is completed, and then placed in the forming area again;

[0020] S5, the salinization soil sample with the required moisture content is prepared, the required soil weight is calculated according to the volume of salinization soil forming area and the target compactness, and the soil is placed in the salinization soil forming area, the soil sample is pressed into the forming area by the mold pressing device, and the salinization soil area with the target moisture content and compacted soil is formed;

[0021] S6, after the sample preparation is completed, the concrete test block simulating the salinization soil erosion environment is formed, and the subsequent durability test is carried out.

[0022] Further, in steps S1-S3, the size of the concrete test mold can be adjusted by changing the position of the key groove of the movable partition to meet the needs of making concrete test pieces of different sizes.

[0023] Further, after the test piece is made, the test mold frame is removed, the soil sample outer wall is wrapped with latex film, and a piece of water-permeable stone is placed on the upper and lower surfaces to control the water migration through the two ends of the sample, which approximates the one-dimensional migration of water, after the sample is immersed in clean water to the saturated moisture content of soil, the sample is taken out and placed in an oven, and dried to the lower limit of soil moisture content, and the dry-wet cycle alternating test is carried out according to the standard of ASTM D4843-88, and then the durability change of concrete in the process of salinization soil dry-wet cycle erosion is determined.

[0024] Further, the concrete freeze-thaw cycle erosion test in the salt-affected soil is carried out in a closed space, and on the basis of the above, the inner latex film and the air-permeable stone are wrapped, then the sealed bag sample is wrapped again, and finally is placed in a sealed box to play a third sealing role, according to the standard of ASTM D560 / D560M-16, the freeze-thaw cycle test is carried out, and after several freeze-thaw cycles, the durability index of the concrete is measured to complete the concrete freeze-thaw cycle erosion test in the salt-affected soil.

[0025] Further, on the basis of the above test, the concrete dry-wet freeze-thaw cycle simulation experiment adopts the four stages of wetting-drying-freezing-thawing to carry out indoor test, and after several times of the above cycle, the durability index of the concrete is measured to complete the concrete dry-wet freeze-thaw cycle erosion test in the salt-affected soil.

[0026] The beneficial effects of the present application are:

[0027] In view of the problem that the existing concrete test mold can only be made in a fixed size, the present application is designed with multiple key grooves at different positions on the side wall of the test mold, which can form different test mold sizes by adjusting the position of the movable partition plate in the key groove. Compared with the existing size-adjustable test mold, the present application is more flexible and convenient to adjust. The assembly and disassembly of the test mold mainly rely on the key grooves provided on the test mold frame and the movable partition plate, which is simpler to operate than the traditional fixed bolt operation, and the precision of the formed test piece is higher. At the same time, the present application is not limited to the number and position of the key grooves shown in the figure, and can be customized according to the size adjustment idea described in the present application.

[0028] In view of the problem that the concrete test piece cannot be attached to the fixed salt-affected soil to form a salt-affected soil erosion environment four weeks after demolding, the present application is designed to only remove or move the partition plate during the demolding stage, and the frame part around the test piece is retained. The space (soil storage area) between the test piece and the test mold frame (or partition plate) can store salt-affected soil, and the salt-affected soil around the test piece can be attached and fixed after demolding.

[0029] In view of the problem that different physical states of salt-affected soil have different erosion effects on concrete, the present application is designed to take soil samples from the place where the research object is located, and determine the moisture content and compaction degree of the salt-affected soil in the test mold according to the moisture content and compaction degree of the backfill soil of the specific concrete project. The test mold is provided with a mold pressing device with the same size as the surface of the salt-affected soil attachment and fixation area, and the soil sample preparation method-pressing method in the standard of soil test method (GBT 50123-2019) is referred to. The soil sample is pressed into the soil storage area by applying static pressure to form a salt-affected soil environment with a target moisture content and compaction degree.

[0030] In view of the fact that there is no clear indoor accelerated deterioration test method for concrete subjected to saline soil erosion (dry-wet cycle, freeze-thaw cycle, dry-wet freeze-thaw cycle, etc.), the concrete test mold subjected to saline soil erosion in the present application can realize long-term durability test of concrete subjected to saline soil erosion in cooperation with the constant temperature and humidity test chamber; in cooperation with the oven, the accelerated deterioration test of concrete subjected to saline soil erosion can be realized; in cooperation with the freeze-thaw cycle machine, the accelerated deterioration test of concrete subjected to saline soil erosion can be realized; the dry-wet freeze-thaw cycle accelerated deterioration test of concrete subjected to saline soil erosion can also be realized by combining the dry-wet cycle with the freeze-thaw cycle. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 It is the overall structure schematic diagram of the concrete test mold of the present application;

[0032] Figure 2 It is the explosion structure schematic diagram of the concrete test mold of the present application;

[0033] Figure 3 It is the three size structure schematic diagram of the concrete test mold of the present application;

[0034] Figure 4 It is the structure schematic diagram of the concrete test mold and the pressing mold device of the present application;

[0035] Figure 5 It is the front view and sectional view structure schematic diagram of the pressing mold device of the present application;

[0036] Figure 6 It is the overall structure schematic diagram of the pressing mold device of the present application;

[0037] Figure 7 It is the explosion structure schematic diagram of the pressing mold device of the present application;

[0038] Figure 8 It is the structure schematic diagram of the pressing mold body of the present application.

[0039] Fig. 1, concrete test mold; 11, test mold frame; 111, vertical key groove; 112, horizontal key groove; 12, longitudinal partition; 13, transverse partition; 14, horizontal partition; 15, bolt fixing hole; 16, salinization soil forming area; 16a, large forming area; 16b, medium forming area; 16c, small forming area; 161, forming area one; 162, forming area two; 163, forming area three; 164, forming area four; 17, concrete forming area; 2, mold pressing device; 21, mold pressing group; 21a, large mold pressing body; 21b, medium mold pressing body; 21c, small mold pressing body; 22, pressing column group; 22a, large pressing column; 22b, medium pressing column; 22c, small pressing column; 23, limiting bolt; 24, water storage cavity; 25, water seepage plate; 26, pressing plate; 27, mounting bolt; 28, mounting screw hole; 29, water inlet; 210, operation notch; 3, support; 4, lifting drive. DETAILED DESCRIPTION

[0040] The application will be further described below in conjunction with the drawings and examples.

[0041] Please refer to Figures 1-8 , the application provides a technical scheme of a concrete test mold for salinization soil erosion environment and a durability test method:

[0042] Example one: the embodiment provides a concrete test mold for salinization soil erosion environment, according to Figure 4 , it comprises a concrete test mold 1, a mold pressing device 2 and a support 3, the mold pressing device 2 is connected below the support 3 through a lifting drive 4, the concrete test mold 1 is directly below the mold pressing device 2, the concrete test mold 1 is provided with a concrete forming area 17 and a salinization soil forming area 16, the lifting drive 4 can drive the mold pressing device 2 to move downward, and the soil in the salinization soil forming area 16 is compacted and formed.

[0043] The specific structure of the concrete test mold 1 is as shown in Figure 1 and Figure 2As shown, the test mold frame 11 and the movable partition are composed. The test mold frame 11 is composed of two isosceles right triangles of the same size, the size is determined according to the size requirement of the test specimen, and a square test mold frame 11 can be formed by combination in use, which mainly functions to fix the movable partition and forms the concrete forming area 17 and the salinization soil forming area 16 together with the partition, and is used for forming the concrete specimen and attaching the required salinization soil. The two isosceles right triangle interfaces of the test mold frame 11 need to be provided with fixing bolts for fixing the test mold frame and preventing the test mold frame from deforming during the specimen forming process. The movable partition includes a set (two) of longitudinal partitions 12, a set (two) of transverse partitions 13 and a horizontal partition 14. The movable partition cooperates with the test mold frame 11 to form the concrete forming area 17 and the salinization soil forming area 16, and mainly plays a role of supporting the specimen. The inner walls of the test mold frame 11 and the movable partition are provided with a plurality of key grooves in the transverse and longitudinal directions, and the longitudinal partitions 12, the transverse partitions 13 and the horizontal partition 14 can be clamped in the key grooves and cooperate with the test mold frame 11 to form concrete forming areas and salinization soil forming areas of different sizes;

[0044] The inner wall of the test mold frame 11 is provided with horizontal key grooves 112 and vertical key grooves 111, the width of the key grooves is the same as (or slightly larger than) the thickness of the longitudinal partition 12 and the horizontal partition 14, so that the partition can be fixed in the key groove and as much as possible without gap. Among them, the horizontal key grooves 112 on the test mold frame 11 are provided with at least 2 rows, which are arranged along the inner wall of the frame, and are mainly used for fixing the horizontal partition 14 and adjusting the position of the horizontal partition. The vertical key grooves 111 on the test mold frame 11 are provided with at least 4 rows (2 pairs), which are arranged vertically along the inner walls of the two side edges of the frame, and are mainly used for fixing or changing the position of the longitudinal partition 12 during the specimen forming process. In this embodiment, the vertical key grooves are provided with 6 rows (3 pairs).

[0045] The size of the horizontal partition 14 matches the size of the horizontal key grooves 112 of the combined test mold frame, so that the horizontal partition 14 can be embedded in the horizontal key grooves 112 of the test mold frame. It mainly serves as the bottom plate of the concrete specimen forming area and the bottom plate for fixing the salinization soil, and the height of the concrete specimen and the thickness of the salinization soil at the bottom of the concrete specimen can be changed by adjusting the position of the horizontal key groove of the test mold frame where the bottom plate is located. In addition, a plurality of sets of longitudinal key grooves are symmetrically arranged on the horizontal partition 14, which are mainly used for fixing the bottom position of the longitudinal partition 12, preventing the bottom of the longitudinal partition 12 from moving during the specimen forming process, and causing the size error of the specimen.

[0046] The dimensions of the longitudinal partition 12 match the vertical keyways 111 inside the assembled mold frame, ensuring that the two longitudinal partitions 12 can be embedded in the two pairs of vertical keyways 111 inside the mold frame. They mainly form the side plates of the concrete specimen forming area. The two longitudinal partitions 12 form the first forming area 161 and the third forming area 163 of the saline soil between the inner wall of the mold frame 11 and the horizontal partition 14, respectively. The width of the concrete specimen and the thickness of the saline soil forming area can be changed by moving the position of the vertical keyways on the mold frame where the two longitudinal partitions are located. Several sets of vertical keyways are symmetrically arranged on the opposite surfaces of the two longitudinal partitions 12, mainly for fixing the transverse partition 13.

[0047] Several groups of transverse partitions 13 are provided, with two in each group and of the same size. The dimensions of the transverse partitions 13 are the same as the spacing of the vertical keyways on the longitudinal partitions 12 of different groups, ensuring that the transverse partitions 13 can be embedded in the vertical keyways on the longitudinal partitions 12. They mainly form the side plates of the concrete specimen molding area. The inner walls of the transverse partitions 13 and the longitudinal partitions 12 form the concrete molding area 17. The outer walls of the transverse partitions 13 and the longitudinal partitions 12 and the mold frame 11 form the molding areas 162 and 164 of the saline soil. The length of the concrete specimen can be changed by moving the position of the vertical keyways on the longitudinal partitions 12 where the two transverse partitions 13 are located.

[0048] This place is Figure 3 For example, the movable partition can cooperate with the test mold frame 11 to form three different sizes of saline soil forming zones 16, namely large forming zone 16a, medium forming zone 16b and small forming zone 16c, and the concrete forming zone 17 adapts to the size of the saline soil forming zone 16.

[0049] After the trial mold assembly, several unused keyways will remain in the concrete forming area. Due to the presence of these empty keyways, the target concrete specimen may not be a standard cube after forming; the bottom and sides of the concrete specimen may develop protrusions and extraneous ridges. To solve this problem, several components corresponding to the keyway dimensions can be configured. During concrete forming, these components are first inserted into the unused empty keyways in the concrete forming area to ensure a smooth surface and guarantee that the formed concrete is a standard cube. Example

[0050] Based on Example 1, such as Figure 6 - Figure 8As shown, the compression molding device 2 comprises a compression molding group 21 formed by three compression molding bodies successively sleeved, including a large compression molding body 21a, a medium compression molding body 21b and a small compression molding body 21c, the compression molding group 21 is used for balancedly applying static pressure in the process of forming the salinized soil, and the size of the compression molding group matches the surface size of the salinized soil forming area 16, that is, the size of the large compression molding body 21a matches the size of the small forming area 16c, the size of the large compression molding body 21a plus the medium compression molding body 21b matches the size of the medium forming area 16b, and the size of the large compression molding body 21a plus the medium compression molding body 21b plus the small compression molding body 21c matches the size of the large forming area 16a.

[0051] A compression column group 22 is vertically arranged above each compression molding body, that is, a large compression column 22a, a medium compression column 22b and a small compression column 22c are vertically arranged above the large compression molding body 21a, the medium compression molding body 21b and the small compression molding body 21c respectively, the small compression column 22c is longitudinally movably sleeved in the medium compression column 22b, the medium compression column 22b is longitudinally movably sleeved in the large compression column 22a, a limiting ring is arranged in the medium compression column 22b and the large compression column 22a for limiting the inner compression column, bolt holes are formed in the corresponding positions of each compression column, and each compression column can be connected together through a limiting bolt 23, or optionally, the outermost two compression columns are connected together, and the outermost large compression column 22a is connected below the support 3 through a lifting driving member 4, which can be an electric push rod or a hydraulic cylinder.

[0052] When the soil in the salinized soil forming area 16 is compacted, the compression molding group 21 matching the size of the salinized soil forming area 16 can be selected: if the salinized soil forming area 16 is the small forming area 16c, the limiting bolt 23 is removed, the lifting driving member 4 controls the downward movement of the compression molding group 21, when the compression molding group 21 contacts the mold frame 11, the medium compression molding body 21b and the small compression molding body 21c are supported on the surface of the solidified concrete, only the large compression molding body 21a continues to be controlled to move downward to compact and form the salinized soil in the small forming area 16c; if the salinized soil forming area 16 is the medium forming area 16b, the large compression column 22a and the medium compression column 22b are connected together through the limiting bolt 23, and the above steps are taken to compact the soil in the medium forming area 16b; if the salinized soil forming area 16 is the large forming area 16a, the three compression columns are all connected together through the limiting bolt 23, and the above steps are taken to compact the soil in the large forming area 16a, so that the soil body can be uniformly compressed to form the salinized soil with the target compactness.

[0053] The plurality of compression mold bodies are arranged, and the operation of the plurality of compression mold bodies is controlled by limiting the cooperation of the bolt 23 and the lifting driving member, so that the compression mold set 21 can be adaptively matched and adjusted according to the size of the salinized soil forming area 16, and the flexibility and diversity of the concrete and salinized soil forming are improved.

[0054] As shown in Figure 5 The internal structures of the large compression mold body 21a, the medium compression mold body 21b and the small compression mold body 21c are the same, which are hollow structures, and a water permeable plate 25 is arranged in the compression mold body, the water permeable plate 25 is provided with water permeable holes, and the water permeable plate 25 divides the compression mold body into a water storage cavity 24 and a compression groove from top to bottom, and a compression plate 26 is detachably installed in the compression groove, the water permeable plate 25 is provided with mounting screw holes 28 penetratingly arranged left and right, and the compression plate 26 is rotatably sleeved with a mounting bolt 27, the compression plate 26 is installed in the compression groove of the compression mold body through the mounting bolt 27, and the compression plates 26 at the bottoms of the compression mold bodies are at the same horizontal plane in the initial state. A water inlet 29 communicating with the water storage cavity 24 is arranged on each compression mold body, and an operation notch 210 exposing the water inlet 29 on the internal compression mold body is arranged on the large compression mold body 21a and the medium compression mold body 21b, so that the water pipe can extend into the water storage cavity 24 of the medium or small compression mold body 21c.

[0055] When the concrete durability test is performed, the compression plate 26 can be removed from the compression mold body, and the compression mold body can be controlled to move downward to the surface of the salinized soil through the lifting driving member, then water is injected into the water storage cavity 24 through the water inlet 29, and the water permeates into the upper surface of the salinized soil through the water permeable plate 25 to wet the salinized soil, thereby simulating the one-dimensional migration of water in the salinized soil.

[0056] Embodiment three: the embodiment provides a durability test method for a salinized soil erosion environment, which comprises the following steps:

[0057] S1, two isosceles right triangle frames are butted through fixing bolts to form a square test mold frame 11, and the horizontal partition plate 14 in the movable partition plate is embedded into the horizontal key groove 112 of the test mold frame during the butting process;

[0058] S2, one group of two longitudinal partition plates 12 is embedded into the vertical key groove on the test mold frame, and the bottom of the longitudinal partition plate 12 is embedded into the horizontal key groove on the horizontal partition plate 14;

[0059] S3, one group of two transverse partition plates 13 is embedded into the vertical key groove on the longitudinal partition plate 12, and the area surrounded by the horizontal partition plate 14, the longitudinal partition plate 12 and the transverse partition plate 13 is the concrete test piece forming area; the outer area is the salinized soil forming area;

[0060] S4, fill the mixed target concrete into the concrete specimen forming area, vibrate, smooth, demold after initial setting, and then put into the forming area after standard curing room curing is completed, and the concrete specimen forming process is performed according to the standard (GB / T 50081-2019);

[0061] S5, refer to the standard (GBT 50123-2019) to prepare the target required water content of the salinized soil sample, calculate the required soil weight according to the salinized soil forming area volume and the target compaction degree, and place the soil in the salinized soil forming area, and press the soil sample into the forming area through the mold pressing device 2 to form the salinized soil area of the target water content and the compacted soil;

[0062] The specific soil filling sequence is as follows:

[0063] a. Move the horizontal partition plate 14 downward to embed into the lower layer horizontal key groove, take out the longitudinal and transverse partition plates 13, 12 and the concrete specimen, fill the soil in the salinized soil forming area five (the space area formed before and after the horizontal partition plate is moved) and compact it to the target compaction degree;

[0064] b. Put the longitudinal partition plate 12, the transverse partition plate 13 and the concrete specimen on the salinized soil forming area five according to the original position;

[0065] c. Remove the transverse partition plate 13, and fill the soil in the salinized soil forming area two 162 and the forming area four 164 (the space area formed by the transverse partition plate 13 and the test mold frame);

[0066] d. Remove the longitudinal partition plate 12, and fill the soil in the salinized soil forming area one 161 and the forming area three 163 (the space area formed by the longitudinal partition plate 12 and the test mold frame);

[0067] e. At this time, the salinized soil forming area (a total of five areas) is completely filled with soil, and the soil in the salinized soil forming area 16 is compacted by the mold pressing device 2;

[0068] S6, after the sample is prepared, the concrete test block simulating the salinized soil erosion environment is formed, and the subsequent durability test is carried out.

[0069] In steps S1-S3, the size of the concrete test mold 1 can be adjusted by changing the position of the movable partition plate in the key groove to meet the needs of making concrete specimens of different sizes. The migration speed of different water content or salt content of salt ions in the soil is different, so the erosion rate of the wrapped concrete is also different. The water content and salt content of the soil can be adjusted during the soil sample preparation process, so as to realize the test research on the influence of different water content or salt content of salinized soil on the durability of concrete. Embodiment

[0070] On the basis of Example Three, after the sample is completed, the mold frame can be removed, the sample is sealed as a whole with a sealed bag to prevent moisture evaporation from changing the soil moisture content, and placed in a constant temperature and humidity test chamber. The durability indicators of the concrete sample are measured regularly. If the saline soil moisture content is low, the soil is difficult to stabilize after the mold frame is removed, and the mold frame can be sealed as a whole without being removed to carry out subsequent durability tests.

[0071] After the sample is completed, the mold frame is removed, the outer wall of the soil sample is wrapped with a latex film, and a piece of water-permeable stone is placed on the upper and lower surfaces. In this way, water migration can only occur through the two ends of the sample, thereby approximately simulating one-dimensional water migration. To solve the problem of inconsistent moisture content in different regions of the sample during wetting and drying, the sample is wetted in both directions and left for 1 hour. This method can control the relative error of the moisture content of each part of the sample to about 1%. After the sample is immersed in clean water to the saturated moisture content of the soil, the sample is taken out and placed in an oven to dry to the lower limit of the soil moisture content. According to the standard of ASTM D4843-88, the sample is subjected to dry-wet cycle alternating test, and the durability change of the concrete during the erosion process of the saline soil under dry-wet cycle is determined.

[0072] The concrete freeze-thaw cycle erosion test is carried out in a sealed space. On the basis of the above-mentioned dry-wet cycle alternating test, the inner latex film and the air-permeable stone are wrapped, and then the sealed bag sample is wrapped again, and finally placed in a sealed box to play the role of the third sealing (in this case, only the temperature of the sample is exchanged, and the interaction between the sample and the external humidity is limited). According to the standard of ASTM D560 / D560M-16, the freeze-thaw cycle alternating test is carried out, and the freeze-thaw temperature is set to -20℃ and 20℃ respectively to ensure that the soil sample experiences complete frost penetration and ice and snow melting during the freeze-thaw process. After several freeze-thaw cycles, the durability indicators of the concrete are measured to complete the concrete freeze-thaw cycle erosion test under saline soil.

[0073] On the basis of the above-mentioned dry-wet cycle alternating test and freeze-thaw cycle erosion test, the concrete dry-wet freeze-thaw cycle alternating process simulation experiment adopts a wetting-drying-freezing-thawing four-stage indoor test. The sample is first humidified to the saturated moisture content, and then the drying process begins. The sample moisture content is reduced from the saturated moisture content to the lower limit, and then humidified to the optimal moisture content. This process is called a dry-wet cycle. When the sample is at the optimal moisture content, it is frozen at -20℃ for 12 hours, and then placed in a 20℃ curing oven for 12 hours to ensure that the ice crystals melt. This process is defined as a freeze-thaw cycle. The combination of the two types of cycles is a dry-wet freeze-thaw cycle of the concrete under saline soil. After several cycles, the durability indicators of the concrete are measured to complete the dry-wet freeze-thaw cycle erosion test of the concrete under saline soil.

[0074] The above description is only the preferred embodiment of the present application, and is not intended to limit the present application. Any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A concrete test form for use in a saline soil erosion environment, characterized by, The utility model relates to a concrete test mould for salinization soil erosion environment, which comprises a concrete test mould, a compression mould device and a support, the compression mould device is connected below the support through a lifting driving element, the concrete test mould is directly below the compression mould device, the concrete test mould is composed of a test mould frame and a movable partition plate, wherein the movable partition plate comprises a set of longitudinal partition plates, a set of transverse partition plates and a horizontal partition plate, a plurality of key grooves are formed on the inner walls of the test mould frame and the movable partition plate in the transverse and longitudinal directions, the horizontal key grooves on the test mould frame are used for fixing and adjusting the position of the horizontal partition plate, the longitudinal partition plates, the transverse partition plates and the horizontal partition plate can be clamped in the key grooves and cooperate with the test mould frame to form concrete forming areas and salinization soil forming areas of different sizes. The compression mould device comprises a compression mould group, the compression mould group is composed of a large compression mould body, a medium compression mould body and a small compression mould body which are sequentially sleeved, the size of the compression mould group is matched with the surface size of the salinization soil forming area, and the compression mould group is used for uniformly applying static pressure in the salinization soil forming process, a compression column group is vertically arranged above each compression mould body, each compression column of the compression column group is sequentially sleeved, and each compression column is connected through a limiting bolt, and the outermost large compression column is connected below the support through a lifting driving element. The internal structures of the large compression mould body, the medium compression mould body and the small compression mould body are the same, and each compression mould body is a hollow structure and is provided with a water permeation plate inside, the water permeation plate divides the inside of the compression mould body into a water storage cavity and a compression groove in the up-down direction, a compression plate is detachably installed in the compression groove, and the compression plates at the bottoms of the compression mould bodies are at the same horizontal plane in the initial state.

2. A concrete test form for a saline soil erosion environment according to claim 1, characterized in that, The test mould frame is composed of two isosceles right-angled triangle structures of the same size, can be combined to form a square test mould frame, is provided with a plurality of horizontal key grooves and vertical key grooves on the inner wall, the width of the key grooves is matched with the thickness of the partition plates, the horizontal key grooves on the test mould frame are used for fixing and adjusting the position of the horizontal partition plate, the vertical key grooves are used for fixing and adjusting the position of the longitudinal partition plate, and the inner wall of the longitudinal partition plate is also provided with vertical key grooves and is used for fixing and adjusting the position of the transverse partition plate.

3. A concrete test form for a saline soil erosion environment according to claim 2, wherein The movable partition plate and the test mould frame can form three salinization soil forming areas of different sizes, i.e., a large forming area, a medium forming area and a small forming area, and the concrete forming area adaptively changes according to the size of the salinization soil forming area.

4. The concrete test cell for a saline soil erosion environment of claim 1, wherein, Large compression columns, medium compression columns and small compression columns are vertically arranged above the large compression mould body, the medium compression mould body and the small compression mould body respectively, the small compression columns are longitudinally movably sleeved in the medium compression columns, the medium compression columns are longitudinally movably sleeved in the large compression columns, and limiting rings are arranged in the medium compression columns and the large compression columns and are used for limiting the compression columns inside.

5. A concrete test form for a saline soil erosion environment according to claim 1, wherein Mounting screw holes are formed on the water permeation plate in the left-right direction, mounting bolts are rotatably sleeved on the compression plates, and the compression plates are mounted in the compression grooves of the compression mould bodies through the mounting bolts.

6. A concrete test form for a saline soil erosion environment according to claim 1, wherein Bolt fixing holes are formed at the interfaces of the two isosceles right-angled triangles of the test mould frame and are used for fixing the test mould frame.

7. A concrete test form for a saline soil erosion environment according to claim 1, wherein Water inlets are formed on each compression mould body and are communicated with the water storage cavities, and operation notches are formed on the large compression mould body and the medium compression mould body and are used for exposing the water inlets on the internal compression mould bodies.

8. A method for durability testing of a salt-affected soil erosion environment, characterized by, The use of the concrete test mould for salinization soil erosion environment according to any one of claims 1-7 comprises the following steps: S1, butt joint two isosceles right triangle frames by fixed bolts, form a square test mold frame, in the butt joint process, embed the horizontal partition in the movable partition into the horizontal key groove of the test mold frame; S2, embed 1 group of 2 longitudinal partitions into the vertical key groove on the test mold frame, and embed the bottom of the longitudinal partition into the horizontal key groove on the horizontal partition; S3, embed 1 group of 2 transverse partitions into the vertical key groove on the longitudinal partition, at this time, the area surrounded by the horizontal partition, the longitudinal partition and the transverse partition is the concrete test piece forming area; the external area is the salinization soil forming area; S4, fill the target concrete after mixing into the concrete test piece forming area, after vibrating, troweling, demolding after initial setting, and then put into the forming area after standard curing room curing; S5, prepare the target required salinization soil sample with water content, calculate the required soil weight according to the salinization soil forming area volume and the target compactness, and place the soil in the salinization soil forming area, press the soil sample into the forming area through the mold pressing device, form the salinization soil area with target water content and compacted soil; S6, after the sample is made, the concrete test block simulating the salinization soil erosion environment is formed, and the follow-up durability test is carried out.

9. The method for durability testing in a saline soil erosion environment according to claim 8, wherein, In steps S1-S3, the size of the concrete test mold is adjusted by changing the position of the key groove where the movable partition is located, to meet the needs of making concrete test pieces of different sizes.

10. The method for durability testing in a saline soil erosion environment of claim 8, wherein, After the test piece is made, the test mold frame is removed, the outer wall of the soil sample is wrapped with latex film, and a piece of water-permeable stone is placed on each of the upper and lower surfaces to control the water migration through only the two ends of the sample, which approximates one-dimensional water migration. After the test piece is immersed in clean water until the soil is saturated with water, it is taken out and placed in an oven, dried to the lower limit of soil moisture content, and subjected to dry-wet cycle alternating test according to the standard of ASTM D4843-88, and then the durability change of concrete under the action of salinization soil dry-wet cycle erosion is determined.

11. The method for durability testing in a saline soil erosion environment according to claim 10, wherein, The concrete salinization soil freeze-thaw cycle erosion test is carried out in a sealed space. Based on the above dry-wet cycle alternating test, the inner latex film and the air-permeable stone are wrapped, and then the sealed bag sample is wrapped twice, and finally placed in a sealed box for the third sealing. According to the standard of ASTM D560 / D560M-16, the freeze-thaw cycle alternating test is carried out, and after several freeze-thaw cycles, the durability index of concrete is measured to complete the concrete salinization soil freeze-thaw cycle erosion test.

12. The method for durability testing in a saline soil erosion environment of claim 11, wherein, Based on the above test, the concrete dry-wet freeze-thaw cycle alternating process simulation test adopts four stages of wetting-drying-freezing-thawing for indoor test, and after several cycles, the durability index of concrete is measured to complete the concrete salinization soil dry-wet freeze-thaw cycle erosion test.

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