A method and device for determining water-binder ratio of fresh concrete

Abstract

A method and device for determining the water-cement ratio of fresh concrete, belonging to the technical field of concrete performance testing. A calibration cylinder is used in conjunction with a truncated cone separation sieve and a cylindrical separation sieve, and the truncated cone separation sieve or the cylindrical separation sieve is used in conjunction with a vibrating screen; all the above instruments are wiped wet, concrete is divided into four equal parts and placed in the calibration cylinder, the concrete in the two calibration cylinders is poured into the cylindrical separation sieve, the sieve is placed in the vibrating screen and fixed, the vibration motor is turned on, the concrete is separated into screened mortar, the sieve is removed, and the mortar is poured into the calibration cylinder, and the above steps are repeated for the other two calibration cylinders; the obtained mortar is mixed and divided into six equal parts into two groups, one group of mortar is subjected to a drying test, and the average mass of water is calculated; the other group of mortar is subjected to a water washing test, and the average mass of cement and other mineral admixtures is calculated, and finally the water-cement ratio is calculated. The present invention ensures the use quality of concrete and improves the safety of concrete.

Description

Technical Field

[0001] The invention relates to a method and a device for determining the water-binder ratio of fresh concrete, belonging to the technical field of concrete performance testing. Background Art

[0002] Concrete refers to an artificial stone made by mixing cement as the main cementitious material with water, sand, gravel, and chemical admixtures and mineral admixtures when necessary, in appropriate proportions, and then uniformly stirred, compacted, and cured and hardened. Concrete is mainly divided into two stages and states: the plastic state before coagulation and hardening, that is, fresh concrete or concrete mixture; the hard state after hardening, that is, hardened concrete or concrete. The water-cement ratio of concrete refers to the ratio of the amount of water used per cubic meter of concrete to the amount of all cementitious materials used.

[0003] The water-binder ratio of concrete is an extremely important factor affecting the strength and quality of concrete. However, in the mixing, transportation, pouring and other links of concrete, the actual water-binder ratio often fluctuates greatly compared with the designed water-binder ratio due to natural or human reasons. In most cases, the actual water-binder ratio is greater than the designed water-binder ratio. As a result, it is difficult to ensure the designed strength and quality of concrete. In addition, in construction, it is difficult to accurately control the water-binder ratio during the concrete mixing process due to various reasons. Summary of the invention

[0004] In order to solve the problems existing in the background technology, the present invention provides a method and device for measuring the water-binder ratio of fresh concrete.

[0005] To achieve the above-mentioned purpose, the present invention adopts the following technical scheme: a device for measuring the water-cement ratio of fresh concrete, comprising a vibrating screen, a cylindrical separation screen, a frustum-type separation screen and a plurality of calibration cylinders, the plurality of calibration cylinders are used in conjunction with the frustum-type separation screen and the cylindrical separation screen, the frustum-type separation screen or the cylindrical separation screen is used in conjunction with the vibrating screen; the vibrating screen comprises a base, a placement seat, a vibration motor, a water outlet pipe, a pressure plate, a top beam, a locking screw, a plurality of shock-absorbing springs and a plurality of auxiliary sliding rods; the base is connected to the placement seat through a plurality of vertically arranged shock-absorbing springs, the bottom of the placement seat is fixed with a vibration motor and is connected to the water outlet pipe, and is fixedly connected to the top beam through a plurality of vertically arranged auxiliary sliding rods, the plurality of auxiliary sliding rods are slidably connected to the edge of the pressure plate and the two can be limited and fixed by the locking screw.

[0006] A method for measuring the water-binder ratio of fresh concrete according to the present invention comprises the following steps:

[0007] Step 1: Wipe the vibrating screen, the cylindrical separation screen, the frustum separation screen and multiple calibration cylinders with a clean damp cloth;

[0008] Step 2: Take 15L to 20L of fresh concrete to be tested, mix well and divide into four parts;

[0009] Step 3: Place the four portions of fresh concrete in step 2 into the corresponding cylinders of the four calibration cylinders and seal them with corresponding sealing covers. The operation time must be shorter than 120 seconds.

[0010] Step 4: Pour the freshly mixed concrete in two of the calibration cylinders in step 3 into the upper screen of the cylinder-type separation screen and seal it with a screen cover;

[0011] Step 5: Place the cylindrical separation screen in step 4 into the vibrating screen and fix it;

[0012] Step 6: Turn on the vibration motor and start vibrating and separating the freshly mixed concrete in the cylindrical separation screen until the mortar in the concrete is sieved out;

[0013] Step 7: Remove the cylindrical separation sieve in step 6, and pour the mortar in the sieve bottom 1 prepared in step 6 into the cylinder of the new calibration cylinder, and seal it with a corresponding sealing cover;

[0014] Step 8: Take the fresh concrete from the other two calibration cylinders in step 3 and repeat steps 4 to 7;

[0015] Step 9: Quickly mix the mortars prepared in step 7 and step 8, and divide them into six portions, and then put them into corresponding containers and seal them respectively;

[0016] Step 10: Randomly divide the six portions of mortar from step 9 into two groups;

[0017] Step 11: Perform a drying test on a group of mortars in step 10, and calculate the average mass of water in the three mortars in the group;

[0018] Step 12: Perform a water washing test on another group of mortars in step 10, and calculate the average mass of cement and other mineral admixtures in the three mortar samples in this group;

[0019] Step 13: Calculate the water-cement ratio of the concrete according to the water-cement ratio formula.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] The invention solves the technical problem of measuring the water-binder ratio of fresh concrete in concrete construction, has strong operability, is convenient, real-time, fast and accurate, can quickly detect the water-binder ratio of concrete in construction, and quickly judge whether the water-binder ratio meets the design requirements, thereby ensuring the quality of concrete in use and improving the safety of concrete. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is the axonometric drawing of the overall structure of the calibration cylinder;

[0023] Figure 2 It is the overall structural axonometric diagram of the vibrating screener;

[0024] Figure 3 It is a schematic diagram of the internal structure when the pressing plate can move freely;

[0025] Figure 4 yes Figure 3 Schematic diagram of the internal structure when locked;

[0026] Figure 5 This is the overall structural axonometric drawing of the cylindrical separation screen. For the sake of clarity, the screen cover is not drawn.

[0027] Figure 6 It is the overall structural axonometric drawing of the frustum-type separation screen. DETAILED DESCRIPTION

[0028] The technical solution of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0029] Specific implementation method 1: Figure 1 to Figure 6 As shown, the present invention discloses a device for measuring the water-cement ratio of fresh concrete, comprising a vibrating screen, a cylindrical separation screen, a frustum-type separation screen and a plurality of calibration cylinders, wherein the plurality of calibration cylinders are used in conjunction with the frustum-type separation screen and the cylindrical separation screen, and the frustum-type separation screen or the cylindrical separation screen is used in conjunction with the vibrating screen; the vibrating screen comprises a base 21, a placement seat 23, a vibration motor 24, a water outlet pipe 25, a pressing plate 27, a top beam 28, a locking screw 29, a plurality of shock-absorbing springs 22 and a plurality of auxiliary sliding rods 26; the upper end of the base 21 is connected to the lower end of the placement seat 23 through a plurality of vertically arranged shock-absorbing springs 22, the bottom of the placement seat 23 is fixed with a vibration motor 24 and is connected to the water outlet pipe 25, and is fixedly connected to the top beam 28 through a plurality of vertically arranged auxiliary sliding rods 26, the plurality of auxiliary sliding rods 26 are slidably connected to the edge of the pressing plate 27 and can be limited and fixed by the locking screw 29.

[0030] Specific implementation method 2: Figure 1As shown, this embodiment is a further explanation of the specific embodiment one, each of the calibration cylinders includes a cylinder body 11 and a sealing cover 12, each of the cylinder bodies 11 is in the shape of an inverted cone and the concrete is sealed by the corresponding sealing cover 12; when in use, the concrete in the corresponding calibration cylinder is poured into the cylindrical separation sleeve, or the mortar separated by the cylindrical separation sleeve is poured into the corresponding calibration cylinder.

[0031] Specific implementation method three: Figure 2 As shown, this embodiment is a further description of the specific embodiment 1. A plurality of inner legs 210 are provided in the placement seat 23 , and the plurality of inner legs 210 are evenly distributed along the circumference of the placement seat 23 .

[0032] Specific implementation method four: Figure 3 , 4 As shown, this embodiment is a further explanation of the specific embodiment three, the edge of the pressure plate 27 is slidably mounted on a plurality of auxiliary slide bars 26, the interior of the pressure plate 27 is provided with a plurality of slide grooves 271 along its radial direction, a locking slide bar 272 is slidably arranged in each of the slide grooves 271, a resisting block movable groove 273 is provided in the middle of the pressure plate 27, the resisting block movable groove 273 is connected to the plurality of slide grooves 271, a threaded hole is provided in the middle of the groove top surface of the resisting block movable groove 273 through the upper surface of the pressure plate 27, the threaded hole is threadedly connected to the vertically arranged locking screw 29, a resisting block 291 is fixed to the lower end of the locking screw 29, the resisting block 291 is an isosceles trapezoidal structure and is located in the resisting block movable groove 273, and each of the locking slide bars 272 is provided with a wedge surface matching the isosceles trapezoid at one end adjacent to the resisting block 291.

[0033] Specific implementation method five: Figure 5 As shown, this embodiment is a further explanation of the specific embodiment three, the cylindrical separation screen comprises a screen cover, an upper screen 31, a lower screen 32 and a screen bottom 33, the screen cover, the upper screen 31, the lower screen 32 and the screen bottom 33 have the same diameter and are connected from top to bottom, the upper screen 31 and the lower screen 32 are both square hole screens and the mesh side length of the upper screen 31 is greater than the mesh side length of the lower screen 32; when in use, the cylindrical separation screen is placed on a plurality of inner legs 210 in the vibrating screen and is fixed by a pressing plate 27, the mesh side length of the upper screen 31 is 9.5 mm, and the mesh side length of the lower screen 32 is 4.75 mm.

[0034] Specific implementation method six: Figure 6As shown, this embodiment is a further explanation of the specific embodiment three, the frustoconical separation screen set includes a frustoconical screen 41 and a screen bottom 42, the screen bottom surface of the frustoconical screen 41 is the same as the diameter of the screen bottom 42, the frustoconical screen 41 and the screen bottom 42 are connected from top to bottom; the screen bottom 42 is provided with a water outlet; when in use, the frustoconical separation screen set is placed on multiple inner legs 210 in the vibrating screen and is pressed and fixed by a pressing plate 27, and the frustoconical screen 41 is a square hole screen with a mesh side length of 0.075 mm.

[0035] Specific embodiment 7: A measuring method according to the measuring device of any specific embodiment of specific embodiments 1 to 6, the method comprising the following steps:

[0036] 1. Preparatory work

[0037] 1. Prepare the concrete construction mix ratio for mixing concrete.

[0038] 2. Detect the mud content and mud block content of fine aggregate (sand). If the on-site inspection of concrete raw materials has been completed, this test can be omitted, and the completed test data can be directly used to calculate the water-cement ratio in the present invention. This test uses a sand and gravel sieve (the test method adopts the current national standard GB / T14684-2011 "Construction Sand" on page 7, Article 7, paragraph 4, and page 9, Article 7, paragraph 6).

[0039] 3. Detect the content of sieve residues greater than 0.075 mm in cement and other mineral admixtures. In order to cooperate with the mortar flushing work during the detection process, the water screening method is used to detect the content of sieve residues greater than 0.075 mm in cement and other mineral admixtures (the test method can refer to the current national standard GB / T1345-2005 "Cement Fineness Test Method Sieve Analysis Method", pages 1 to 5, items 5 to 8). The sieve used to detect the content of sieve residues greater than 0.075 mm in cement and the sieve used to detect the mud content of fine aggregates are both 0.075 mm square hole sieves, which is the same as the above step 2. And the vibration combined with the water screening method is also used to detect the content of sieve residues greater than 0.075 mm in cement. This is the originality of the present invention.

[0040] 4. It should be noted that the above detection method is only applicable to the present invention and cannot be used as a basis for determining whether the fineness of cement and other mineral admixtures is qualified or not, because according to the current national standards: the sieve used to detect the fineness of cement and other mineral admixtures has a 0.08mm square hole sieve, not a 0.075mm square hole sieve.

[0041] 5. The purpose of the present invention is that: in the process of determining the water-cement ratio, when the mortar is washed by vibration combined with the water sieve method, cement particles smaller than 0.075 mm in the cement and soil smaller than 0.075 mm in the fine aggregate are washed down the sieve together. This invention is convenient for the detection operation and the subsequent calculation work.

[0042] 6. The purpose of detecting the content of sieve residues larger than 0.075 mm in cement and other mineral admixtures is not to detect the actual fineness of cement, but to calculate the mass of sieve residues larger than 0.075 mm in cement. This part of particles is included in the sieve residues larger than 0.075 mm after mortar washing and drying, and is mixed with fine aggregates.

[0043] 7. After completing steps 2 and 6, combined with the theoretical mix ratio of concrete, the mass of mud and mud blocks smaller than 0.075 mm in fine aggregate can be calculated, and the mass of sieve residue larger than 0.075 mm in cement can be calculated, laying the foundation for the present invention to measure and calculate the mass of cement in mortar.

[0044] 8. After completing the above work, the mass of cement in the mortar can be calculated.

[0045] (II) Main instruments

[0046] 1. Multiple concrete calibration cylinders;

[0047] 2. A cylindrical separation sieve set (including a sieve cover, an upper sieve 31 (4.75 mm square hole sieve), a lower sieve 32 (9.5 mm square hole sieve) and a sieve bottom 33, one each);

[0048] 3. A truncated cone separation set of screens (including a truncated cone screen 41 (0.075 mm square hole screen) and a sieve bottom 42, one each);

[0049] 4. Vibrating screener;

[0050] 5. Electronic balance: one with a maximum weighing capacity of 10kg and a sensitivity of 0.01g; one with a maximum weighing capacity of 5kg and a sensitivity of 0.01g; one with a maximum weighing capacity of 1kg and a sensitivity of 0.01g.

[0051] 6. One blast drying box and three electric furnaces;

[0052] 7. Auxiliary equipment: faucet, iron plate, shovel, spatula, brush, rag, air conditioner, humidifier

[0053] (III) Laboratory environment

[0054] 1. Temperature: 20±5℃

[0055] 2. Humidity: 70%RH≤humidity≤85%RH

[0056] (IV) Determination method of water-binder ratio of fresh concrete

[0057] Step 1: Wipe the vibrating screen, the cylindrical separation screen, the frustum separation screen and multiple calibration cylinders with a clean damp cloth to ensure that the fresh concrete does not absorb moisture when in contact with them;

[0058] Step 2: Take 15L to 20L of fresh concrete to be tested, mix well and divide into four parts;

[0059] Step 3: Place the four portions of fresh concrete in step 2 into the cylinder bodies 11 of the corresponding four calibration cylinders, and seal them with corresponding sealing covers 12. The operation time must be shorter than 120 seconds.

[0060] Take 15L to 20L of representative fresh concrete of which water-binder ratio is to be measured, pour it on a pre-wet iron plate, stir it quickly and thoroughly, and pile it into a round cake shape with a gradually higher center. Then divide it into four equal parts by quartering method, fill four concrete calibration cylinders with these four parts of concrete diagonally, and weigh the concrete in the four concrete calibration cylinders with a balance to ensure the same mass, and seal them with sealing caps 12. The whole operation process should be completed within 120s.

[0061] Step 4: Pour the freshly mixed concrete in two of the calibration cylinders in step 3 into the upper screen 31 of the cylindrical separation screen set, and seal it with a screen cover;

[0062] Step 5: Place the cylindrical separation screen in step 4 into the vibrating screen and fix it;

[0063] Place the cylindrical separation screen set on multiple inner legs 210 of the vibrating screen, push the pressure plate 27 until it is fully pressurized on the screen cover, rotate the locking screw 29 to move upward, and then drive the resistance block 291 to move upward, and then push the multiple locking slide bars 272 to squeeze the corresponding auxiliary slide bars 26, and then fix the position of the pressure plate 27, that is, fix the cylindrical separation screen set. The fixing principle of the following frustum-type separation screen set is the same as the above process.

[0064] Step 6: Turn on the vibration motor 24 to start vibrating and separating the freshly mixed concrete in the cylindrical separation screen until the mortar in the concrete is screened out;

[0065] Step 7: Remove the cylindrical separation screen in step 6, and pour the mortar in the screen bottom 1 prepared in step 6 into the cylinder 11 of the new calibration cylinder, and seal it with the corresponding sealing cover 12;

[0066] Step 8: Take the fresh concrete from the other two calibration cylinders in step 3 and repeat steps 4 to 7;

[0067] Pour the concrete in two of the concrete calibration cylinders into the cylindrical separation sieve, which consists of a 9.5mm square hole sieve, a 4.75mm square hole sieve and a sieve bottom. Cover the sieve cover and place the sieve on the vibrating screen and fix it. Start the vibrating screen and start vibrating the concrete in the cylindrical separation sieve until the mortar in the concrete is basically sieved out. Remove the sieve and pour all the mortar in the sieve bottom into the spare concrete calibration cylinder, and cover the sealing cover 12 of the concrete calibration cylinder. Repeat the above operation for the concrete in the remaining two concrete calibration cylinders.

[0068] Step 9: Quickly mix the mortars prepared in step 7 and step 8, and divide them into six portions, and then put them into corresponding containers and seal them respectively;

[0069] Step 10: Randomly divide the six portions of mortar from step 9 into two groups;

[0070] Combine the mortar under the 4.75mm sieve after two screenings into a concrete calibration cylinder and mix quickly and evenly. Evenly weigh 6 portions of the mixed mortar, each with a mass of 500g, and divide them into 6 enamel trays of appropriate size prepared in advance. Randomly divide the 6 weighed samples into two groups, with three portions of mortar in each group for standby use.

[0071] Assuming that the components (ingredients) of the two groups of three mortars (a total of six parts) are exactly the same, the "equal amount substitution method" is applied to share the same components and the same mass data in the "water washing test" and "drying test", and finally the water-binder ratio of the concrete is accurately calculated. The calculation method of the water-binder ratio of fresh concrete is the ratio of water used to mix concrete to cement and other mineral admixtures.

[0072] Step 11: Perform a drying test on a group of mortars in step 10, and calculate the average mass of water in the three mortars in the group;

[0073] Step 12: Perform a water washing test on another group of mortars in step 10, and calculate the average mass of cement and other mineral admixtures in the three mortar samples in this group;

[0074] Step 13: Calculate the water-cement ratio of the concrete according to the water-cement ratio formula.

[0075] The above two groups of mortars were subjected to drying and water washing tests respectively. After the drying test, the average mass of water in the three mortar samples can be calculated. After the water washing test, the average mass of cement and other mineral admixtures in the three mortar samples can be calculated. The water-binder ratio of the concrete can be calculated according to the water-binder ratio formula. The specific test process and methods are described as follows.

[0076] Specific implementation eight: According to the determination method described in specific implementation seven, the step eleven comprises the following steps:

[0077] Step 1: Randomly select the group of mortars and weigh three portions of them respectively, and then put them into a blast drying oven that has been heated to 105±5℃ in advance and dry them to constant weight; constant weight means that when the interval between two consecutive weighings is greater than 3h, the difference between the two weighings is less than the weighing precision required for the test, the same below.

[0078] Step 2: Take out the mortar from step 1 and put it into a dryer. After cooling to room temperature, weigh the mass to an accuracy of 0.01g.

[0079] Step 3: Calculate the average mass of the three mortars in the above group after drying.

[0080] For the three dried mortars, the masses of the three mortars before drying are m1, m2, and m3 respectively, and the masses of the three mortars after drying are m′1, m′2, and m′3 respectively. The average mass of the three mortars after drying is The calculation formula is Suppose the mass of water in the three portions of mortar is w1, w2, and w3 respectively, then w1 = m1-m'1, w2 = m2-m'2, and w3 = m3-m'3. Suppose the average mass of water in the three portions of mortar is but The mass units of mortar and water in the above formulas are all g, and the calculation is accurate to 0.01g. The arithmetic mean of the mass of water in the three mortar samples is taken as the measured value.

[0081] Specific implementation method 9: According to the determination method described in specific implementation method 7, step 12 includes the following steps:

[0082] Step 1: randomly select a portion of mortar from the other group of mortar and pour it into the frustum sieve 41 of the frustum sieve separation set;

[0083] Step 2: Place the round table separation sieve in step 1 into the vibrating sifter and fix it;

[0084] Step 3: Fix the truncated cone separation screen set, and use the water flow from the tap facing the screen set to fully rinse the mortar in the truncated cone screen 41, and turn on the vibration motor 24 at the same time, and use the water flow to rinse the mortar in the screen set while vibrating and screening, until the fine aggregate, cement and other mineral admixtures in the mortar are completely rinsed, and the water flowing out of the water outlet at the bottom of the screen set becomes completely clear water. The working time is about 200s to 300s;

[0085] Step 4: Turn off the power supply and water flow, and put the remaining materials on the frustum-type separation sieve into the corresponding container;

[0086] Step 5: Repeat steps 2 to 4 for the other two portions of mortar;

[0087] Step 6: Carefully transfer the remaining materials on the three portions of mortar from step 4 and step 5 to appropriate enamel trays (be careful not to lose any of the sieve residue), and then simultaneously place the remaining materials in the above three containers into a blast drying oven preheated to 105±5℃ and dry to constant weight;

[0088] Step 7: Take out the mortar from step 6 and put it into a dryer. After cooling to room temperature, weigh the mass to an accuracy of 0.01g.

[0089] Step 8: Calculate the average mass of the three remaining materials in the above group after drying.

[0090] Assume that the average mass of the remaining material in the three mortars after washing and drying is The corresponding average mass of washed mud and mud blocks is

[0091] Assume that the average mass of cement and other mineral admixtures in the three washed mortar samples before washing is After washing, it is separated into two parts, one part is the part below the sieve of less than 0.075mm, and the other part is the part below the sieve of less than 0.075mm. It means that this part has been washed away by water during the washing process and its mass is not considered when weighing; the other part is the part larger than 0.075mm, which is Indicates that this part is the screen residue.

[0092] Calculate the average mass of cement and other mineral admixtures:

[0093]

[0094] Where:

[0095] ——The average mass of cement and other mineral admixtures in three washed mortar samples, in g, accurate to 0.01g.

[0096] ——The average mass of the three mortar samples after drying, in g, accurate to 0.01 g. This value can be directly calculated from step three in specific implementation mode eight.

[0097] ——The average mass of the sieve residues of the three mortar samples used for water washing after drying, in g, accurate to 0.01 g. This value can be directly obtained from step eight in specific implementation method nine.

[0098] ——The average mass of mud and mud blocks smaller than 0.075 mm in three portions of mortar fine aggregate, in grams, accurate to 0.01 grams. This data can be obtained from step 2 in (I) preparatory work.

[0099] ——The average mass of the residues on the sieve with a mesh size of 0.075 mm of cement and other mineral admixtures in the three portions of mortar, in grams, accurate to 0.01 grams. This data can be obtained from step 3 in the preparatory work (I).

[0100] Calculate the water-cement ratio of concrete

[0101] According to the definition of water-binder ratio, the water-binder ratio of concrete is the mass of water divided by the mass of cement and other mineral admixtures. That is:

[0102] Where:

[0103] ——The average mass of water in the three mortar samples used for drying, in g, accurate to 0.01 g. This value can be directly calculated by the eighth specific implementation method.

[0104] ——The average mass of cement and other mineral admixtures in the three mortar samples used for water washing, in g, accurate to 0.01g. This value is calculated in Specific Implementation Method 9.

[0105] (V) Description of the Invention

[0106] 1. In the above steps, when using a blast drying box to dry mortar or drying the residual material on the sieve, in order to improve the work efficiency, an electric furnace can be used for drying. Using this method to dry the material, all tests can be completed within 100min to 120min; using the previous drying method, it takes about 210min to 240min to complete all tests. Using the electric furnace drying method to dry the material can increase the work efficiency by about 2 times. Using a blast drying box to dry the material is the standard method, and using an electric furnace to dry the material is the substitute method. Users can select by themselves.

[0107] 2. The present invention has been tested in engineering practice for many years and combined with a large number of experimental verifications, which show that the absolute error between the measured water-binder ratio of fresh concrete and the theoretical water-binder ratio is between ±(0.002-0.008), which has extremely high practical value.

[0108] 2. Other instructions

[0109] (1) Concrete calibration cylinder

[0110] 1. Basic information of concrete calibration cylinder:

[0111] The material is Q235C carbon structural steel, and the surface roughness is R a 3.2, its volume is about 2.2L.

[0112] 2. The function of concrete calibration cylinder:

[0113] (1) Used to calibrate the quality of concrete to ensure that the quality of concrete used for separating mortar is the same.

[0114] (2) Used to evenly distribute the components of concrete to ensure that the content and quality of the various components of the mortar used to separate fine aggregate, cement and mineral admixtures are basically the same.

[0115] (3) It is used to temporarily preserve concrete and keep the mixing water in the concrete from volatilizing, so as to ensure that the mixing water contained in the fresh concrete is not lost before the drying test, so as to ensure the accuracy of the present invention and the test.

[0116] (4) Temporarily store the mortar to prevent the mixing water in the mortar from volatilizing, so as to ensure that the mixing water contained in the mortar is not lost before the drying test, so as to ensure the accuracy of the present invention and the test.

[0117] (5) Used as a mortar mixer to mix mortar evenly.

[0118] 3. How to use the concrete calibration cylinder:

[0119] (1) Take 15L to 20L of representative fresh concrete of which the water-binder ratio is to be measured, pour it on a pre-wet iron plate, stir it quickly and thoroughly, and pile it into a round cake shape with a gradually higher center. Then divide it into four equal parts using the quartering method, and fill four concrete calibration cylinders with these four parts of concrete diagonally. Use a balance to weigh the concrete in the four concrete calibration cylinders to ensure that the mass is the same. At the same time, seal the tops of the four concrete calibration cylinders and keep them for later use. The entire operation should be completed within 120 seconds.

[0120] (2) Pour the concrete in two of the concrete calibration cylinders into the cylinder-type separation sieve, cover the sieve cover, and place the sieve cover on the vibrating screen and fix it. Start the vibrating screen to vibrate the concrete in the separation sieve cover until the mortar in the concrete is basically screened out. Remove the sieve cover, pour all the mortar in the sieve bottom into the spare concrete calibration cylinder, and cover the sealing cover 12 of the concrete calibration cylinder. Then repeat the above operation for the concrete in the remaining two concrete calibration cylinders.

[0121] (3) Combine the mortar under the 4.75 mm sieve after two screenings into a concrete calibration cylinder and mix quickly and evenly. Evenly weigh 6 portions of the mixed mortar, each with a mass of 500 g, and divide them into 6 enamel trays of appropriate size. Randomly divide the 6 weighed samples into two groups, with three portions of mortar in each group for standby use.

[0122] (II) Cylindrical separation screen

[0123] 1. Basic information of the drum separation screen:

[0124] The material is Q235C carbon structural steel, and the inner surface roughness is R a 3.2.

[0125] 2. The function of the cylindrical separation screen:

[0126] (1) Used to separate coarse aggregate and mortar in concrete.

[0127] (2) Because concrete contains a lot of coarse aggregate and has a relatively large mass, two-grade sieves are used for screening, namely, 9.5mm square hole sieve and 4.75mm square hole sieve, which is quicker and more convenient to operate.

[0128] 3. How to use the cylindrical separation screen:

[0129] (1) Take 15L to 20L of representative fresh concrete of which the water-binder ratio is to be measured, pour it on a pre-wet iron plate, stir it quickly and thoroughly, and pile it into a round cake shape with a gradually higher center. Then divide it into four equal parts using the quartering method, and fill four concrete calibration cylinders with these four parts of concrete diagonally. Use a balance to weigh the concrete in the four concrete calibration cylinders to ensure that the mass is the same. At the same time, seal the tops of the four concrete calibration cylinders and keep them for later use. The entire operation should be completed within 120 seconds.

[0130] (2) Pour the concrete in two of the concrete calibration cylinders into the cylinder-type separation sieve, cover the sieve cover, and place the sieve cover on the vibrating screen and fix it. Start the vibrating screen to vibrate the concrete in the separation sieve cover until the mortar in the concrete is basically screened out. Remove the sieve cover, pour all the mortar in the sieve bottom into the spare concrete calibration cylinder, and cover the sealing cover 12 of the concrete calibration cylinder. Then repeat the above operation for the concrete in the remaining two concrete calibration cylinders.

[0131] (III) Round table separation screen

[0132] 1. Basic information of round table separation screen:

[0133] The material is Q235C carbon structural steel, and the surface roughness is R a 3.2.

[0134] 2. Function of round table separation screen:

[0135] Used to separate fine aggregate, cement and other mineral admixtures in mortar.

[0136] 3. How to use the round table separation screen:

[0137] (1) Take out any one of the other three mortar samples and pour it into the frustoconical separation sieve. Fix the sieve, turn on the tap facing the sieve, and let the tap water fully rinse the mortar in the sieve. At the same time, start the power of the vibrating screener, and use tap water to rinse the mortar in the sieve while vibrating and screening. Continue for about 200s to 300s until all the fine aggregate cement and other mineral admixtures in the mortar are rinsed clean, and the water flowing out of the water outlet 42 at the bottom of the sieve becomes completely clear. At this time, the power supply and tap can be turned off. Then, refer to the above steps to complete the water washing test for the remaining two mortars to be washed.

[0138] (2) Carefully transfer the three portions of mortar, including the residual fine aggregate on the sieve, to suitable enamel trays (be careful not to lose any residual fine aggregate on the sieve), and then place them simultaneously in a forced air drying oven preheated to 105±5℃, dry to constant weight, carefully take them out and place them in a desiccator, and weigh them separately after cooling, with an accuracy of 0.01g.

[0139] (IV) Vibrating screener

[0140] 1. Basic information of vibration screener:

[0141] The placement seat 23, the pressure plate 27, the top beam 28, and the plurality of auxiliary slide bars 26 are all made of Q235C carbon structural steel;

[0142] The material of the base 21 is 12 # and 8 # Channel steel;

[0143] The plurality of shock absorbing springs 22 are 70 # Wire spring steel;

[0144] The power of the vibration motor 24 is 0.5 kW, the speed is 1460 r / min, and the voltage is 380 v.

[0145] 2. The function of vibration screener:

[0146] Used to assist in separating coarse aggregate and mortar in concrete; used to assist in separating fine aggregate and cement and other mineral admixtures in mortar.

[0147] 3. How to use the vibration screener:

[0148] (1) Take 15L to 20L of representative fresh concrete of which the water-binder ratio is to be measured, pour it on a pre-wet iron plate, stir it quickly and thoroughly, and pile it into a round cake shape with a gradually higher center. Then divide it into four equal parts using the quartering method, and fill four concrete calibration cylinders with these four parts of concrete diagonally. Use a balance to weigh the concrete in the four concrete calibration cylinders to ensure that the mass is the same. At the same time, seal the tops of the four concrete calibration cylinders and keep them for later use. The entire operation should be completed within 120 seconds.

[0149] (2) Pour the concrete in two of the concrete calibration cylinders into the cylinder-type separation sieve, cover the sieve cover, and place the sieve cover on the vibrating screen and fix it. Start the vibrating screen to vibrate the concrete in the separation sieve cover until the mortar in the concrete is basically screened out. Remove the sieve cover, pour all the mortar in the sieve bottom into the spare concrete calibration cylinder, and cover the sealing cover 12 of the concrete calibration cylinder. Then repeat the above operation for the concrete in the remaining two concrete calibration cylinders.

[0150] (3) Take out any one of the other three mortar samples for backup and pour it into the frustum-type separation sieve set, fix the sieve set, turn on the tap facing the sieve set, and let the tap water fully rinse the mortar in the sieve set. At the same time, start the power supply of the vibrating screener, and use tap water to rinse the mortar in the sieve set while vibrating and screening, and continue for about 200s to 300s, until all the cementitious materials such as fine aggregate cement and other mineral admixtures in the mortar are rinsed clean, and the water flowing out of the water outlet 42 of the bottom of the sieve completely becomes clear water. At this time, the power supply and tap can be turned off. Then, the remaining two mortars to be washed with water are respectively subjected to the water washing test in accordance with the above steps.

[0151] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other carrier forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations within the meaning and range of equivalents of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0152] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A method for determining the water-cement ratio of fresh concrete, the method being based on the determination device, the determination device comprising a vibrating screen, a cylindrical separation screen, a frustoconical separation screen and a plurality of calibration cylinders, the plurality of calibration cylinders being used in conjunction with the frustoconical separation screen and the cylindrical separation screen, the frustoconical separation screen or the cylindrical separation screen being used in conjunction with the vibrating screen; the vibrating screen comprising a base (21), a placement seat (23), a vibration motor (24), a water outlet pipe (25), a pressure plate (27), a top beam (28), a locking The invention relates to a base (21) comprising a plurality of vertically arranged shock absorbing springs (22), a plurality of auxiliary sliding rods (26), and a plurality of vertically arranged auxiliary sliding rods (26). The base (21) is connected to the placement seat (23) through a plurality of vertically arranged shock absorbing springs (22). A vibration motor (24) is fixed to the bottom of the placement seat (23) and is connected to the water outlet pipe (25). The vibration motor (24) is fixed to the bottom of the placement seat (23) and is connected to the water outlet pipe (25). The vibration motor (24) is fixed to the top beam (28) through a plurality of vertically arranged auxiliary sliding rods (26). The plurality of auxiliary sliding rods (26) are slidably connected to the edge of the pressure plate (27) and the two can be limited and fixed by a locking screw (29). The invention is characterized in that: The method comprises the following steps: Step 1: Wipe the vibrating screen, the cylindrical separation screen, the frustum separation screen and multiple calibration cylinders with a clean damp cloth; Step 2: Take 15L to 20L of fresh concrete to be tested, mix well and divide into four parts; Step 3: Place the four portions of fresh concrete in step 2 into the cylinder bodies (11) of the corresponding four calibration cylinders, and seal them with corresponding sealing covers (12). The operation time must be shorter than 120 seconds. Step 4: pour the freshly mixed concrete in two of the calibration cylinders in step 3 into the upper screen (31) of the cylindrical separation screen set, and seal it with a screen cover; Step 5: Place the cylindrical separation screen in step 4 into the vibrating screen and fix it; Step 6: Turn on the vibration motor (24) to start vibrating and separating the freshly mixed concrete in the cylindrical separation screen until the mortar in the concrete is screened out; Step 7: Remove the cylindrical separation sieve in step 6, and pour the mortar in the sieve bottom 1 obtained in step 6 into the cylinder (11) of the new calibration cylinder, and seal it with a corresponding sealing cover (12); Step 8: Take the fresh concrete from the other two calibration cylinders in step 3 and repeat steps 4 to 7; Step 9: Quickly mix the mortars prepared in step 7 and step 8, and divide them into six portions, and then put them into corresponding containers and seal them respectively; Step 10: Randomly divide the six portions of mortar from step 9 into two groups; Step 11: Perform a drying test on a group of mortars in step 10, and calculate the average mass of water in the three mortars in the group; Step 12: Perform a water washing test on another group of mortars in step 10, and calculate the average mass of cement and other mineral admixtures in the three mortar samples in this group; Step 13: Calculate the water-cement ratio of the concrete according to the water-cement ratio formula.

2. The method for measuring the water-binder ratio of fresh concrete according to claim 1, characterized in that: Each calibration cylinder comprises a cylinder body (11) and a sealing cover (12); each cylinder body (11) is in the shape of an inverted truncated cone and is sealed by a corresponding sealing cover (12); when in use, the concrete in the corresponding calibration cylinder is poured into the cylinder-type separation sieve, or the mortar separated by the cylinder-type separation sieve is poured into the corresponding calibration cylinder.

3. The method for measuring the water-binder ratio of fresh concrete according to claim 1, characterized in that: A plurality of inner supporting feet (210) are arranged in the placement seat (23), and the plurality of inner supporting feet (210) are evenly distributed along the circumference of the placement seat (23).

4. The method for measuring the water-binder ratio of fresh concrete according to claim 3, characterized in that: The edge of the pressure plate (27) is slidably mounted on a plurality of auxiliary slide bars (26), a plurality of slide grooves (271) are radially arranged inside the pressure plate (27), a locking slide bar (272) is slidably arranged in each of the slide grooves (271), a resisting block movable groove (273) is arranged in the middle of the pressure plate (27), the resisting block movable groove (273) is connected to the plurality of slide grooves (271), and the groove top of the resisting block movable groove (273) is A threaded hole is provided in the middle of the surface and passes through the upper surface of the pressure plate (27), and the threaded hole is threadedly connected to a vertically arranged locking screw (29). A resistance block (291) is fixed to the lower end of the locking screw (29), and the resistance block (291) is an isosceles trapezoidal structure and is located in the movable groove (273) of the resistance block. Each locking slide rod (272) is provided with a wedge surface matching the isosceles trapezoid at one end adjacent to the resistance block (291).

5. The method for measuring the water-binder ratio of fresh concrete according to claim 3, characterized in that: The cylindrical separation screen comprises a screen cover, an upper screen (31), a lower screen (32) and a screen bottom (33); the screen cover, the upper screen (31), the lower screen (32) and the screen bottom (33) have the same diameter and are connected from top to bottom; the upper screen (31) and the lower screen (32) are both square hole screens and the side length of the mesh of the upper screen (31) is greater than the side length of the mesh of the lower screen (32); when in use, the cylindrical separation screen is placed on a plurality of inner legs (210) in the vibrating screen and is pressed and fixed by a pressing plate (27).

6. The method for measuring the water-binder ratio of fresh concrete according to claim 3, characterized in that: The frustoconical separation screen set comprises a frustoconical screen (41) and a second screen bottom (42); the screen bottom surface of the frustoconical screen (41) and the second screen bottom (42) have the same diameter; the frustoconical screen (41) and the second screen bottom (42) are connected in a sleeve manner from top to bottom; the second screen bottom (42) is provided with a water outlet; when in use, the frustoconical separation screen set is placed on a plurality of inner legs (210) in a vibrating screen and is pressed and fixed by a pressing plate (27).

7. The method for measuring the water-binder ratio of fresh concrete according to claim 6, characterized in that: The step eleven comprises the following steps: Step 1: randomly select the group of mortars, weigh three portions of the mortars respectively, and simultaneously place them in a blast drying oven that has been heated to 105±5°C, and dry them to constant weight; Step 2: Take out the mortar in step 1 and put it into a dryer, and weigh the mass after cooling to room temperature; Step 3: Calculate the average mass of the three mortars in the above group after drying. m烘干砂浆 .

8. The method for measuring the water-binder ratio of fresh concrete according to claim 7, characterized in that: The step twelve comprises the following steps: Step 1: Select a portion of mortar from the other group of mortars and pour it into the frustum sieve (41) of the frustum sieve set; Step 2: Place the round table separation sieve in step 1 into the vibrating sifter and fix it; Step 3: flush the mortar in the truncated cone screen (41) with water, and simultaneously start the vibration motor (24) until the water flowing out of the water outlet pipe (25) completely turns into clear water; Step 4: Turn off the power supply and water flow, and put the remaining materials on the frustum-type separation sieve into the corresponding container; Step 5: Repeat steps 2 to 4 for the other two portions of mortar; Step 6: Place the remaining materials in the above three containers into a blast drying oven preheated to 105±5°C and dry to constant weight; Step 7: Take out the mortar in step 6 and put it into a dryer, and weigh the mass after cooling to room temperature; Step 8: Calculate the average mass of the three remaining materials in the above group after drying. m水洗砂浆筛余 .

Images