A method for detecting water retention of building mortar

Abstract

The invention relates to a method for detecting water retention of building mortar. The water retention detection method adopts special water retention detection equipment for detection. The special water retention detection equipment has a feeding unit, a static unit, a drying unit and a mold. The invention places a base layer slice directly on the mold filled with a mortar mixture, so that the lower end surface of the base layer slice is in direct contact with the mortar mixture to absorb water and measure the water retention of the mortar. The invention solves the problem that the base layer slice is not deformable and cannot come into contact with the mortar mixture to absorb water if an isolating metal mesh is required. The invention can detect the water retention of the mortar for different base layers, and provide a basis for optimizing the addition amount of a water retaining agent for different base layers. In addition, by weighing the mass of the base layer slice dried to a constant weight before water absorption and the mass of the base layer slice dried to a constant weight after water absorption, the influence of sand particles attached to the surface of the base layer slice on the experimental data is effectively eliminated, thereby improving the accuracy of the experimental data.

Description

Technical Field

[0001] The present invention relates to the technical field of mortar building materials, and in particular to a method for detecting water retention of building mortar. Background Art

[0002] The water retention of a manhole refers to the ability of the mortar to retain moisture. Since all base layers that require mortar construction have a certain degree of water absorption, after the base layer absorbs the moisture in the mortar, the construction deformation of the mortar will be poor. In severe cases, the gel material in the mortar cannot be fully hydrated, resulting in a decrease in strength, especially the interface strength between the hardened mortar and the base layer, causing the mortar to crack and fall off. If the mortar has appropriate water retention properties, it can effectively improve the workability of the mortar and prevent the moisture in the mortar from being absorbed by the base layer, ensuring the full hydration of the cement. During the mortar production process, water-retaining agents are usually added to increase its viscosity and water retention. Since water-retaining agents are expensive, excessive use of water-retaining agents will directly lead to increased product costs and excessive product annual size, which in turn makes on-site construction of the product difficult. If the amount of water-retaining agent used is too low, the product will lose water excessively before setting, resulting in low product strength.

[0003] According to the water retention test method in the "Standard for Test Methods for Basic Properties of Building Mortar (JGJ / T 70-2009)," medical cotton yarn is used to cover the mortar surface. Eight pieces of medium-speed qualitative filter paper are then placed over the yarn to absorb moisture from the mortar mixture for a specified period of time. The filter paper is then weighed and the mortar's water retention is calculated. Because the medical cotton yarn has a certain degree of water absorption, which can affect the accuracy of the water retention data, a non-absorbent metal mesh is used in its place to reduce the amount of mortar sand adhering to the filter paper.

[0004] However, for different base layers corresponding to mortar construction (such as red bricks, aerated blocks, etc.), different base layers have different water absorption properties, different requirements for the water retention of mortar, and different amounts of water-retaining agents required to be added. If different base layers are used to replace the filter paper and the above standards are used for testing, the base layer has a certain hardness, and the use of a metal mesh will prevent the base layer from contacting the mortar mixture, making it impossible to perform water retention testing. However, if the base layer is to be directly attached to the surface of the mortar mixture to meet the water absorption requirements, the sand particles in the mortar mixture will easily adhere to the surface of the base layer due to the certain roughness of the base layer surface, thereby affecting the accuracy of the water retention test data.

[0005] Chinese invention patent publication number CN110954682B provides a method for testing the water retention of gypsum mortar. The method includes: determining the components of the gypsum mortar, preparing two samples with water retention agent dosages of 0.2% and 0.3%, stirring the samples, and then testing and calculating them; preparing an air-containing building block, laying the block flat, and marking a 200mm spacing on the surface of the block with a marker; placing iron blocks of different heights along the left and right edges of the spacing; spreading the mixed gypsum mortar sample material between the two iron blocks, and then scraping it into a sloped shape with a scraper to ensure that the left and right sides of the material are consistent in height with the left and right iron blocks, respectively; placing it at room temperature for curing, and after the gypsum mortar is completely solidified and hardened, obtaining the minimum thickness of the water-retaining portion of the gypsum mortar. Although this method uses aerated blocks as the base layer for testing, it is only applicable to on-site operations and can only perform qualitative analysis on the water retention of the mortar, but cannot perform quantitative analysis to obtain accurate values ​​of the water retention rate of the mortar with different amounts of water retaining agent added.

[0006] Therefore, the present invention proposes a method for detecting water retention of building mortar to solve the above problems. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to provide a method for detecting the water retention of building mortar, which can detect the water retention of mortar for different base layers and obtain accurate mortar water retention rate, providing a basis for optimizing the amount of water retention agent added for different base layers.

[0008] To solve the above technical problems, the technical solution of the present invention is: a method for detecting the water retention of building mortar. The innovation of the method is that the water retention detection method uses a dedicated water retention detection device for detection. The dedicated water retention detection device has a feeding unit, a static unit, a drying unit and a mold. The water retention detection method includes the following steps:

[0009] Step 1: Slice the substrate to be inspected to obtain a substrate slice;

[0010] Step 2: Place the base slices in a drying unit and dry them to a constant weight, and quickly weigh the mass M1 of the base slices at this time;

[0011] Step 3: Move the dried base slice to a stationary unit, place it at room temperature, and absorb moisture in the air until it reaches a constant weight. Weigh the mass M2 of the base slice at this time.

[0012] Step 4: Weigh the mass M3 of the mold, add excess mortar mixture into the mold through the feeding unit, and use a scraper to scrape off the mortar mixture that exceeds the mold, and weigh the mass M4 of the mold containing the mortar mixture;

[0013] Step 5: Place the base slice on the surface of the mortar mixture and let it stand for a period of time, then remove the base slice and quickly weigh the mass M5 of the base slice at this time;

[0014] Step 6: Move the base slices and the mold containing the mortar mixture to a drying unit and dry them to constant weight. Quickly weigh the mass M6 of the base slices and the mass M7 of the mold containing the mortar mixture.

[0015] Step 7: Calculate the water retention rate W of the mortar mixture according to the calculation formula, which is: W=(1-(M5-M2-(M6-M1)) / (M4-M3-(M7-M3+M6-M1))×100%.

[0016] Furthermore, in step 5, the standing time is 2-10 minutes.

[0017] Furthermore, in step 5, when weighing the mass M5 of the base slice, the contact surface between the base slice and the mortar mixture is facing upward for weighing.

[0018] Furthermore, the dedicated water retention detection device includes a housing;

[0019] The housing has a cylindrical cavity with a vertical central axis, and three partition plates are radially distributed in the radial direction of the cylindrical cavity. The three partition plates divide the cylindrical cavity into three fan-shaped cavities, and the feeding unit, the static unit and the drying unit are respectively arranged in the three fan-shaped cavities. The housing side wall of each fan-shaped cavity is provided with a take-in and put-out opening, and each take-in and put-out opening is hinged with a door panel;

[0020] A rotating shaft is coaxially provided in the housing, and the rotating shaft is driven to rotate by a first driving member. The mold is connected to the rotating shaft via a horizontally arranged first connecting plate and rotates as the rotating shaft rotates. A third T-shaped through-slot for accommodating the mold is provided on a side of the upper end surface of the first connecting plate away from the rotating shaft. The mold is movably placed in the third T-shaped through-slot, and the step surface of the third T-shaped through-slot serves as a supporting surface for the mold. A sample holding groove for holding a mortar mixture is provided on the upper end surface of the mold.

[0021] A T-shaped closing module is provided above the mold, and the upper rotating sleeve of the rotating shaft is provided with a shaft sleeve, and the shaft sleeve is driven to rotate by a second driving member. The T-shaped closing module is connected to the shaft sleeve through a horizontally arranged second connecting plate and rotates with the shaft sleeve. A first T-shaped through-slot is provided on the upper end surface of the second connecting plate to accommodate the T-shaped closing module and for the T-shaped closing module to move up and down. The T-shaped closing module is arranged in the first T-shaped through-slot and is connected to the stepped surface of the first T-shaped through-slot by a spring. A second T-shaped through-slot for placing the mold slice is provided on the T-shaped closing module, and the stepped surface of the second T-shaped through-slot is the supporting surface of the mold slice. The upper end surface of the mold is provided with an avoidance groove for the bottom of the T-shaped closing module to move into for film closing.

[0022] Furthermore, each partition plate is provided with a passage for the mold and the T-shaped closing module to rotate through, and a push plate is provided on the partition plate for controlling the opening and closing of the passage. A movable groove for the push plate to move vertically is provided in the partition plate, and the push plate is arranged in the movable groove and is driven to move by a third driving member.

[0023] Furthermore, the feeding unit includes a feeding mechanism, a weighing mechanism and a pressing mechanism;

[0024] The feeding mechanism includes a feeding hopper, a horizontally arranged conveying pipe and a vertically arranged discharge pipe. The feeding hopper and the conveying pipe are both mounted on the upper end surface of the casing. The discharge port of the feeding hopper is connected to the feeding port of the conveying pipe. A spiral pushing blade is provided in the conveying pipe. The spiral pushing blade is driven to rotate by a fourth driving member. The discharge pipe is arranged in the casing. The feeding port of the discharge pipe is connected to the discharge port of the conveying pipe. A valve is installed at the discharge port of the discharge pipe.

[0025] The weighing mechanism is arranged on one side of the feeding mechanism, and the weighing mechanism includes a horizontally arranged electronic scale. A lifting rod is vertically installed at the bottom of the electronic scale. The lifting rod is driven up and down by a fifth driving member, and drives the electronic scale to move up and down. The electronic scale moves upward and enters the third T-shaped through slot to lift the mold for weighing, or enters the second T-shaped through slot to lift the mold slice for weighing;

[0026] The pressing mechanism includes a pressing plate, which is movably arranged above the T-shaped closing module and is driven by a sixth driving member to move up and down away from or close to the T-shaped closing module.

[0027] Furthermore, the feeding mechanism also includes a scraper, which is hinged to the lower part of the outer side wall of the discharge pipe. The scraper is driven to rotate upward or downward by a seventh driving member, and a residual material recovery pool is provided below the scraper.

[0028] Furthermore, the first connecting plate has two branches extending horizontally outward from one side away from the rotating shaft to form a Y-shaped structure. The first connecting plate has two third T-shaped through slots, one of which is provided on each branch. A space for the electronic scale to move through is formed between the two branches.

[0029] The structure of the second connecting plate is the same as that of the first connecting plate. There are two first T-shaped through slots, which are respectively opened on each branch portion of the second connecting plate.

[0030] Furthermore, the top and bottom of the casing of the stationary unit are both provided with air circulation openings, and protective nets are installed at the air circulation openings.

[0031] Furthermore, the drying unit includes an electric heating plate, which is arranged at the bottom of the casing. Air holes are opened on the top of the casing at the drying unit, and insulation layers are provided on the inner walls of the casing and the side walls of the partition plate around the drying unit.

[0032] The advantages of the present invention are:

[0033] (1) The detection method of the present invention places the base slice directly on the mold filled with mortar mixture, so that the lower end surface of the base slice directly contacts the mortar mixture to absorb water and measure the water retention of the mortar. This solves the problem that the base slice is not deformable and cannot contact the mortar mixture to absorb water if the metal mesh is isolated. The water retention of the mortar can be detected for different base layers, providing a basis for optimizing the amount of water retaining agent added for different base layers. In addition, by weighing the mass of the base slice dried to a constant weight before water absorption and the base slice dried to a constant weight after water absorption, the influence of sand particles attached to the surface of the base slice on the experimental data is effectively eliminated, thereby improving the accuracy of the experimental data.

[0034] (2) In the present invention, when weighing the mass M5 of the base slice, the base slice is weighed with the contact surface between the base slice and the mortar mixture facing upward to avoid the sand particles attached to the base slice being transferred to the surface of the electronic scale during weighing, thereby affecting the accuracy of the experimental data.

[0035] (3) The special water retention testing equipment in the present invention realizes the semi-automatic operation of the water retention test of the base layer slices, eliminating the interference of human factors on the experimental data.

[0036] (4) The first connecting plate in the present invention is a Y-shaped structure, and there are two third T-shaped through grooves, which are respectively opened on each branch part. A space for the electronic scale to move through is formed between the two branches. The structure of the second connecting plate is the same as that of the first connecting plate. This arrangement can not only enable the equipment to complete two experiments for comparison at the same time, but also enable the electronic scale to weigh the mold slice placed on the second connecting plate by rotating the first connecting plate slightly so that the branches of the first connecting plate and the branches of the second connecting plate are staggered. The electronic scale can pass between the two branches of the first connecting plate and lift the mold slice for measurement. Moreover, when the mold and mold slice containing the mortar mixture are dried at the same time, the above-mentioned method can also be used to stagger them, which will not affect the function realization and effectively save the internal layout space of the equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0038] Figure 1 Schematic diagram of the special water retention detection equipment in the present invention.

[0039] Figure 2 This is a distribution diagram of the feeding unit, static unit, drying unit and mold of the present invention.

[0040] Figure 3 It is a structural schematic diagram of the partition plate and the push plate of the present invention.

[0041] Figure 4 It is a structural schematic diagram of the feeding unit of the present invention.

[0042] Figure 5 It is a structural schematic diagram of the feeding mechanism of the present invention.

[0043] Figure 6 It is a schematic diagram of the connection between the scraper and the discharge pipe of the present invention.

[0044] Figure 7 It is a structural schematic diagram of the static unit of the present invention.

[0045] Figure 8 It is a structural schematic diagram of the drying unit of the present invention.

[0046] Figure 9 It is a schematic diagram of the mold of the present invention and the T-shaped clamping module.

[0047] Figure 10 It is an enlarged view of point A of the present invention. DETAILED DESCRIPTION

[0048] The following embodiments may enable those skilled in the art to more fully understand the present invention, but the present invention is not limited to the scope of the embodiments.

[0049] The present invention provides a method for detecting water retention of building mortar, which adopts a special water retention detection device for detection. The special water retention detection device comprises a feeding unit 2, a static unit 3, a drying unit 4 and a mold 5.

[0050] like Figure 1-10 As shown, the special water retention testing equipment includes a casing 1, and the casing 1 has a cylindrical cavity with a vertical central axis. Three partition plates 11 are radially distributed in the radial direction of the cylindrical cavity. The three partition plates 11 divide the cylindrical cavity into three fan-shaped cavities. The feeding unit 2, the static unit 3 and the drying unit 4 are respectively arranged in the three fan-shaped cavities. A take-in and put-out opening is opened on the side wall of the casing of each fan-shaped cavity, and a door panel 12 is hinged at each take-in and put-out opening.

[0051] A rotating shaft 51 is coaxially provided in the casing 1, and the rotating shaft 51 is driven to rotate by a first driving member 52. The first driving member 52 adopts a rotating motor. The first driving member 52 is installed at the bottom of the casing 1, and the output end of the first driving member 52 passes through the casing and is connected to the rotating shaft 51. The mold 5 is connected to the side wall of the rotating shaft 51 through a horizontally arranged first connecting plate 53, and rotates as the rotating shaft 51 rotates. A third T-shaped through groove 531 for placing the mold 5 is provided on the side of the upper end surface of the first connecting plate 53 away from the rotating shaft 51. The mold 5 is movably placed in the third T-shaped through groove 531. The step surface of the third T-shaped through groove 531 is the support surface of the mold 5. The upper end surface of the mold 5 is provided with a sample holding groove 501 for holding mortar mixture.

[0052] A T-shaped closing module 6 is provided above the mold 5. The upper rotating sleeve of the rotating shaft 51 is provided with a sleeve 61. The bottom of the rotating shaft 51 is rotatably mounted on the casing 1 through a first bearing. The top and middle of the rotating shaft 51 are rotatably connected to the inner side of the sleeve 61 through two second bearings. The outer side of the sleeve 61 is rotatably connected to the casing 1 through a third bearing. The sleeve 61 is driven to rotate by a second driving member 62. The second driving member 62 adopts a rotating motor. The second driving member 62 is installed on the top of the casing 1, and the sleeve 61 passes upward through the casing 1 and is connected to the output end of the second driving member 62.

[0053] The T-shaped closing module 6 is connected to the side wall of the sleeve 61 through a horizontally arranged second connecting plate 63, and rotates with the rotation of the sleeve 61. A first T-shaped through groove 631 is provided on the upper end surface of the second connecting plate 63 to accommodate the T-shaped closing module 6 and allow the T-shaped closing module 6 to move up and down. The T-shaped closing module 6 is arranged in the first T-shaped through groove 631 and is connected to the stepped surface of the first T-shaped through groove 631 through a spring 632. A second T-shaped through groove 601 is provided on the T-shaped closing module 6 for placing the mold slice. The stepped surface of the second T-shaped through groove 601 is the supporting surface of the mold slice. The upper end surface of the mold 5 is provided with an avoidance groove 502 for the bottom of the T-shaped closing module 6 to move into for film closing.

[0054] In this embodiment, each partition plate 11 is provided with a passage 111 for the mold 5 and the T-shaped closing module 6 to rotate through, and the partition plate 11 is provided with a push plate 12 for controlling the opening and closing of the passage 111. A movable groove for the push plate 112 to move vertically is provided in the partition plate 11. The push plate 112 is movable and arranged in the movable groove and is driven to move by a third driving member 113. The third driving member is an electric push rod. The third driving member 113 is installed on the top of the casing. The telescopic end of the third driving member 113 passes through the casing and is connected to the push plate 112. The third driving member 113 pulls the push plate 12 to move upward to open the passage 111. The mold 5 and the T-shaped closing module 6 each rotate through the passage 111, thereby realizing automatic passage between the fan-shaped cavities without manual operation.

[0055] The feeding unit 2 includes a feeding mechanism, a weighing mechanism and a pressing mechanism.

[0056] The feeding mechanism includes a feeding hopper 211, a horizontally arranged conveying pipe 212 and a vertically arranged discharge pipe 213. The feeding hopper 211 and the conveying pipe 212 are both mounted on the upper end surface of the casing 1. The discharge port of the feeding hopper 211 is connected to the feed port of the conveying pipe 212. A spiral pushing blade 214 is provided in the conveying pipe 212. The spiral pushing blade 214 is driven to rotate by a fourth driving member 215. The fourth driving member 215 adopts a rotating motor. The discharge pipe 213 is arranged in the casing 1 and is located in the middle of the fan-shaped cavity. Space for accommodating the first connecting plate 53 is reserved on both sides of the discharge pipe 213. The feeding of the discharge pipe 213 The outlet is connected to the discharge port of the conveying pipe 212, and a valve 216 is installed at the discharge port of the discharge pipe 213; the feeding mechanism also includes a scraper 217, the top side of the scraper 217 is hinged to the lower part of the outer wall of the discharge pipe 213, and the scraper 217 is driven to rotate upward or downward by the seventh drive member 218. A residual material recovery pool 219 is provided below the scraper 217, and the seventh drive member 218 adopts an electric push rod. The seventh drive member 218 is installed on the outer wall of the discharge pipe 213 through a mounting seat and is located above the scraper 217. The top of the seventh drive member 218 is hinged to the mounting seat, and the telescopic end of the seventh drive member 218 is hinged to the scraper 217.

[0057] The weighing mechanism is arranged on one side of the feeding mechanism, and the weighing mechanism includes a horizontally arranged electronic scale 221. The electronic scale 221 is arranged on the side of the scraper 217 away from the discharge pipe 213. A lifting rod 222 is vertically installed at the bottom of the electronic scale 221. The lifting rod 222 is driven up and down by the fifth driving member 223, and drives the electronic scale 221 to move up and down. The fifth driving member 223 adopts an electric push rod. The fifth driving member 223 is installed at the bottom of the casing 1. The telescopic end of the fifth driving member 223 passes through the casing 1 and is connected to the lifting rod 222. The electronic scale 221 moves upward and enters the third T-shaped through slot 531 to lift the mold 5 upward for weighing, or enters the second T-shaped through slot 601 to lift the mold slice upward for weighing.

[0058] The pressing mechanism includes a horizontally arranged lower pressing plate 231, which is movably arranged above the T-shaped closing module 6 and is driven up and down by the sixth driving member 232 to move away from or close to the T-shaped closing module 6. The lower pressing plate 231 is arranged directly above the electronic scale 221, and the sixth driving member 232 adopts an electric push rod. The sixth driving member 232 is installed on the top of the casing 1, and the telescopic end of the sixth driving member 232 is connected to the lower pressing plate 231 through a guide rod 233. The outer side of the guide rod 233 is movably sleeved with a guide sleeve 234, and the guide sleeve 234 is fixedly installed on the casing 1 through a mounting frame.

[0059] In this embodiment, the first connecting plate 53 has two branches extending horizontally outward from one side of the rotating shaft 51, forming a Y-shaped structure. Two third T-shaped through-slots 531 are provided, one in each branch, for use in control experiments. A space is formed between the two branches for the electronic scale 221 to move through. The second connecting plate 63 has the same structure as the first connecting plate 51, with two first T-shaped through-slots 631 provided, one in each branch of the second connecting plate 63. When the electronic scale weighs a mold slice placed on the second connecting plate 63, it only needs to rotate the first connecting plate 53 slightly, so that the branches of the first connecting plate 53 and the branches of the second connecting plate 63 are staggered. The electronic scale can then pass between the two branches of the first connecting plate 53, lift the mold slice, and measure it. Furthermore, when drying the mold and mold slices containing the mortar mixture simultaneously, the staggered placement described above can be used, without affecting functionality and effectively saving internal layout space.

[0060] The top and bottom of the housing of the stationary unit 3 are provided with air vents 31, each of which is fitted with a protective screen 32. The drying unit 4 includes an electric heating plate 41 disposed at the bottom of the housing 1. Air vents 42 are provided at the top of the housing at the drying unit. Insulation layers are provided on the inner walls of the drying unit and on the sidewalls of the partition plate to prevent heat loss from the drying unit.

[0061] The method for testing water retention using the above-mentioned dedicated water retention testing equipment comprises the following steps:

[0062] Step 1: Slice the base layer to be tested to obtain a base layer slice 7. The size of the base layer slice 7 is larger than the inner diameter of the mold;

[0063] Step 2: Place the base slices in the drying unit and dry them to a constant weight. Quickly weigh the mass M1 of the base slices at this time. The detailed steps are as follows: Place the base slices in the T-shaped closing module 6, rotate the T-shaped closing module 6 into the drying unit 4 to dry them to a constant weight, then rotate the T-shaped closing module 6 to the top of the electronic scale 221 in the feeding unit 2, move the electronic scale 221 upward to push the base slices away from the T-shaped closing module 6, and weigh the base slices to obtain M1;

[0064] Step 3, move the dried base slice to the static unit, place it at room temperature, and absorb moisture in the air to constant weight, and weigh the mass M2 of the base slice at this time. The detailed steps are as follows: move the electronic scale 221 downward, and place the base slice weighed to obtain M1 into the T-shaped closing module 6, rotate the T-shaped closing module 6 into the static unit, let it stand at room temperature, and absorb moisture in the air to constant weight, rotate the T-shaped closing module 6 to the top of the electronic scale 221 in the feeding unit 2, move the electronic scale 221 upward, push the base slice away from the T-shaped closing module 6, weigh the base slice, and obtain M2. This operation is used to eliminate the increase in mass caused by the base slice absorbing moisture in the air, thereby affecting the accuracy of the data results;

[0065] Step 4: Weigh the mass of the mold M3, add excess mortar mixture into the mold through the feeding unit, and use a scraper to scrape off the mortar mixture that is higher than the mold, and weigh the mass of the mold containing the mortar mixture M4. The detailed steps are as follows:

[0066] Step 4-1: Rotate the T-shaped closing module 6 to one side, rotate the mold 5 to the top of the electronic scale 221, move the electronic scale 221 upward to push the mold away from the first connecting plate 53, weigh the mold 5 to obtain M3, and move the electronic scale 221 downward to return the bottom of the mold 5 to the first connecting plate 53;

[0067] Step 4-2: Add a sufficient amount of mortar mixture into the feed hopper 211 of the feed unit, open the valve of the discharge pipe 213, start the fourth driving member 215 to drive the spiral push blade 214 to rotate, and drive the mortar mixture into the discharge pipe 213 until the mortar mixture flows out of the discharge port of the discharge pipe 213. Then close the valve, and the excess mortar mixture falls into the residual material recovery tank 219 below;

[0068] Step 4-3: Rotate the mold 5 to the position directly below the discharge port of the discharge pipe 213, open the valve, start the fourth driving member 215, and discharge the mortar mixture into the mold 5 until a sufficient amount is obtained;

[0069] Step 4-4: Close the valve and the fourth driving member 215, rotate the scraper 217 downward to the upper end surface of the mold 5, rotate the mold 5, and use the scraper 217 to scrape the mortar mixture that protrudes from the mold, and the excess mortar mixture falls into the residual material recovery tank 219;

[0070] Step 4-5: Rotate the mold 5 to the electronic scale and weigh the mass M4 of the mold containing the mortar mixture;

[0071] Step 5: Place the base slice on the surface of the mortar mixture and let it stand for a while. Then remove the base slice and quickly weigh the mass M5 of the base slice at this time. The detailed steps are as follows:

[0072] Step 5-1: Rotate the T-shaped closing module 6 to move the base slice to the top of the mold 5. Move the lower pressing plate 231 downward to push the base slice downward to fit the upper end surface of the mold 5, overcoming the spring force. The base slice now covers the mortar mixture in the mold 5 and is left to stand for 10 minutes.

[0073] Step 5-2: The lower pressing plate 231 moves upward, and the base slice is moved away from the mold under the action of the spring force. The base slice is manually turned over so that the contact surface of the base slice with the mortar mixture faces upward and is placed on the T-shaped closing module 6;

[0074] Step 5-3: Rotate the mold to one side and weigh the mass M5 of the base slice at this time using an electronic scale;

[0075] Step 6: Move the base slices and the mold containing the mortar mixture to the drying unit and dry them to constant weight. Then, rotate the T-shaped module 6 and the mold 5 to the electronic scale in sequence, and quickly weigh the mass M6 of the base slices and the mass M7 of the mold containing the mortar mixture.

[0076] Step 7: Calculate the water retention rate W of the mortar mixture according to the calculation formula, which is: W=(1-(M5-M2-(M6-M1)) / (M4-M3-(M7-M3+M6-M1))×100%.

[0077] For a mortar mixture that needs to be constructed on red bricks, the detection method of the present invention is used to test red brick slices, and the water retention rate is 94.8%. When the mortar mixture is tested using filter paper according to the "Standard for Test Methods for Basic Properties of Building Mortar (JGJ / T 70-2009)", the water retention rate is 91.5%. The water retention rate obtained by the red brick slice test in the present invention is more accurate. According to the mortar mixture construction requirement of more than 92%, the amount of water retaining agent used can be appropriately reduced to save costs.

[0078] The detection method of the present invention places the base slice directly on the mold filled with the mortar mixture, so that the lower end surface of the base slice is directly in contact with the mortar mixture to absorb water and measure the water retention of the mortar, which solves the problem that the base slice is not deformable and cannot come into contact with the mortar mixture to absorb water if an isolating metal mesh is used. The water retention of the mortar can be detected for different base layers, providing a basis for optimizing the amount of water retaining agent added for different base layers. In addition, by weighing the mass of the base slice dried to a constant weight before water absorption and the base slice dried to a constant weight after water absorption, the influence of sand particles attached to the surface of the base slice on the experimental data is effectively eliminated, thereby improving the accuracy of the experimental data. The special water retention detection equipment realizes the semi-automatic operation of the water retention experiment of the base slice, eliminating the interference of human factors on the experimental data.

[0079] Those skilled in the art will appreciate that the present invention is not limited to the foregoing embodiments. The foregoing embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and modifications are intended to fall within the scope of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for detecting water retention of building mortar, characterized in that: The water retention detection method is performed using a dedicated water retention detection device, which includes a feeding unit, a static unit, a drying unit, and a mold. The water retention detection method includes the following steps: Step 1: Slice the substrate to be inspected to obtain a substrate slice; Step 2: Place the base slices in a drying unit and dry them to a constant weight, and quickly weigh the mass M1 of the base slices at this time; Step 3: Move the dried base slice to a stationary unit, place it at room temperature, and absorb moisture in the air until it reaches a constant weight. Weigh the mass M2 of the base slice at this time. Step 4: Weigh the mass M3 of the mold, add excess mortar mixture into the mold through the feeding unit, and use a scraper to scrape off the mortar mixture that exceeds the mold, and weigh the mass M4 of the mold containing the mortar mixture; Step 5: Place the base slice on the surface of the mortar mixture and let it stand for a period of time, then remove the base slice and quickly weigh the mass M5 of the base slice at this time; Step 6: Move the base slices and the mold containing the mortar mixture to a drying unit and dry them to constant weight. Quickly weigh the mass M6 of the base slices and the mass M7 of the mold containing the mortar mixture. Step 7: Calculate the water retention rate W of the mortar mixture according to the calculation formula, which is: W=(1-(M5-M2-(M6-M1)) / (M4-M3-(M7-M3+M6-M1))×100%.

2. The method for detecting water retention of building mortar according to claim 1, wherein: In step 5, the standing time is 2-10 minutes.

3. The method for detecting water retention of building mortar according to claim 1, wherein: In step 5, when weighing the mass M5 of the base slice, the base slice is weighed with the contact surface between the base slice and the mortar mixture facing upward.

4. The method for detecting water retention of building mortar according to claim 1, wherein: The dedicated water retention testing equipment includes a housing; The housing has a cylindrical cavity with a vertical central axis, and three partition plates are radially distributed in the radial direction of the cylindrical cavity. The three partition plates divide the cylindrical cavity into three fan-shaped cavities, and the feeding unit, the static unit and the drying unit are respectively arranged in the three fan-shaped cavities. The housing side wall of each fan-shaped cavity is provided with a take-in and put-out opening, and each take-in and put-out opening is hinged with a door panel; A rotating shaft is coaxially provided in the housing, and the rotating shaft is driven to rotate by a first driving member. The mold is connected to the rotating shaft via a horizontally arranged first connecting plate and rotates as the rotating shaft rotates. A third T-shaped through-slot for accommodating the mold is provided on a side of the upper end surface of the first connecting plate away from the rotating shaft. The mold is movably placed in the third T-shaped through-slot, and the step surface of the third T-shaped through-slot serves as a supporting surface for the mold. A sample holding groove for holding a mortar mixture is provided on the upper end surface of the mold. A T-shaped closing module is provided above the mold, and the upper rotating sleeve of the rotating shaft is provided with a shaft sleeve, and the shaft sleeve is driven to rotate by a second driving member. The T-shaped closing module is connected to the shaft sleeve through a horizontally arranged second connecting plate and rotates with the shaft sleeve. A first T-shaped through-slot is provided on the upper end surface of the second connecting plate to accommodate the T-shaped closing module and for the T-shaped closing module to move up and down. The T-shaped closing module is arranged in the first T-shaped through-slot and is connected to the stepped surface of the first T-shaped through-slot by a spring. A second T-shaped through-slot for placing the mold slice is provided on the T-shaped closing module, and the stepped surface of the second T-shaped through-slot is the supporting surface of the mold slice. The upper end surface of the mold is provided with an avoidance groove for the bottom of the T-shaped closing module to move into for film closing.

5. The method for detecting water retention of building mortar according to claim 4, wherein: Each partition plate is provided with a passage for the mold and the T-shaped closing module to rotate through, and a push plate is provided on the partition plate for controlling the opening and closing of the passage. A movable groove for the push plate to move vertically is provided in the partition plate, and the push plate is arranged in the movable groove and is driven to move by a third driving member.

6. The method for detecting water retention of building mortar according to claim 4, wherein: The feeding unit includes a feeding mechanism, a weighing mechanism and a pressing mechanism; The feeding mechanism includes a feeding hopper, a horizontally arranged conveying pipe and a vertically arranged discharge pipe. The feeding hopper and the conveying pipe are both mounted on the upper end surface of the casing. The discharge port of the feeding hopper is connected to the feeding port of the conveying pipe. A spiral pushing blade is provided in the conveying pipe. The spiral pushing blade is driven to rotate by a fourth driving member. The discharge pipe is arranged in the casing. The feeding port of the discharge pipe is connected to the discharge port of the conveying pipe. A valve is installed at the discharge port of the discharge pipe. The weighing mechanism is arranged on one side of the feeding mechanism, and the weighing mechanism includes a horizontally arranged electronic scale. A lifting rod is vertically installed at the bottom of the electronic scale. The lifting rod is driven up and down by a fifth driving member, and drives the electronic scale to move up and down. The electronic scale moves upward and enters the third T-shaped through slot to lift the mold for weighing, or enters the second T-shaped through slot to lift the mold slice for weighing; The pressing mechanism includes a pressing plate, which is movably arranged above the T-shaped closing module and is driven by a sixth driving member to move up and down away from or close to the T-shaped closing module.

7. The method for detecting water retention of building mortar according to claim 6, wherein: The feeding mechanism also includes a scraper, which is hinged to the lower part of the outer side wall of the discharge pipe. The scraper is driven to rotate upward or downward by a seventh driving member, and a residual material recovery pool is provided below the scraper.

8. The method for detecting water retention of building mortar according to claim 6, wherein: The first connecting plate has two branches extending horizontally outward from one side away from the rotating shaft to form a Y-shaped structure. The third T-shaped through slots are provided with two branches, one on each branch, and a space for the electronic scale to move through is formed between the two branches. The structure of the second connecting plate is the same as that of the first connecting plate. There are two first T-shaped through slots, which are respectively opened on each branch portion of the second connecting plate.

9. The method for detecting water retention of building mortar according to claim 4, wherein: The top and bottom of the casing of the stationary unit are both provided with air circulation openings, and protective nets are installed at the air circulation openings.

10. The method for detecting water retention of building mortar according to claim 4, wherein: The drying unit includes an electric heating plate, which is arranged at the bottom of the casing. The top of the casing at the drying unit is provided with air holes, and the inner wall of the casing around the drying unit and the side wall of the partition plate are all provided with insulation layers.

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