Inactive micro-powder saturated surface dry sample forming and testing all-in-one machine and testing method

Abstract

The invention discloses an inactive micro-powder saturated surface dry sample forming and testing all-in-one machine and a testing method, and the testing method comprises the following steps: step 1, sieving a to-be-tested sample, and soaking the to-be-tested sample until the to-be-tested sample is in a water absorption saturation state to obtain wet powder; step 2, filling the green sand into a forming mold to prepare a powder tire; 3, pressure is applied to the surface, in the thickness direction, of the powder tire in the forming mold step by step and maintained for a certain time, when the displacement deformation delta, in the thickness direction, of the powder tire does not exceed 0.001 mm within 30 min, pressure application is stopped, and a sample in a saturated surface dry state is obtained; and step 4, taking out the sample reaching the saturated surface dry state, putting the sample into a weighing box, respectively weighing the weight m of the sample before drying and the weighing box and the weight ms of the sample after drying and the weighing box, and calculating the saturated surface dry water absorption rate of the sample. The method has the beneficial effects that the four steps of sample forming, drying, saturated surface dry state judgment and saturated surface dry water absorption calculation are integrated, and the measurement accuracy and convenience are remarkably improved.

Description

Technical Field

[0001] The present application relates to the field of micro-powder saturated dry surface detection methods, and in particular to an inactive micro-powder saturated dry surface sample forming and testing all-in-one machine and testing method. Background Art

[0002] As an important parameter, the saturated surface dry water absorption rate has a great influence on the concrete mix design and quality control. Therefore, it is necessary to accurately measure the saturated surface dry water absorption rate of sand and gravel. The saturated surface dry water absorption rate of coarse aggregate can be tested by the basket method. Use a wrung soft cloth to wipe off the free water on the surface until the free water film disappears and the shiny water marks are no longer visible. This is the saturated surface dry state. The saturated surface dry water absorption rate of fine aggregate can be determined by the slump cone method, but it is difficult to judge the saturated surface dry state of fine powder (<0.075mm) for the following reasons: ① The tested sample should have a uniform moisture distribution; ② The instrument should have a high accuracy to detect small changes in the moisture content of the tested sample; ③ The temperature and humidity of the testing environment may affect the drying process of the sample. At present, the current standards and specifications do not have a clear measurement method for judgment. Without the guidance of quantitative test indicators, the test data has large errors and is time-consuming and labor-intensive. The Chinese patent application document with publication number CN105043942A discloses a method for using a quantitative determination device for the saturated surface dry state of fine aggregate, which is a method of letting sand flow down through a funnel, then measuring the height of the sand pile, and judging whether the sand has reached the saturated surface dry state by the height of the sand pile. This method solves the problem that the saturated surface dry state requires subjective judgment by people, but the test process still needs to switch back and forth between the two steps of drying the sample and judging the saturated surface dry state. The test process is still very cumbersome, the test time is still long, and the micro powder (i.e., the powder particle size <0.075mm) needs to be screened out during the test, resulting in the method being unable to measure micro powder with a powder particle size <0.075mm.

[0003] Therefore, in order to effectively solve the problem that the saturated dry water absorption rate of micropowder is difficult to quantify, an inactive micropowder saturated dry water absorption rate test method is urgently needed to improve the device and method for accurately measuring the saturated dry water absorption rate of micropowder. Summary of the invention

[0004] In view of the above-mentioned shortcomings of the prior art, the purpose of the present application is to provide an all-in-one machine and method for forming and testing a non-active micro-powder saturated surface dry sample, so as to solve the problem that the current micro-powder saturated surface dry water absorption rate is difficult to quantify.

[0005] To solve the above problems, the technical solution adopted in this application is:

[0006] A method for testing the saturated surface dryness of inactive micropowder, characterized in that it comprises the following steps:

[0007] Step 1: sieve the sample to be tested and soak it until it is saturated with water to obtain a wet powder;

[0008] Step 2: Fill the wet powder into a forming mold to make a powder tire;

[0009] Step 3, applying pressure step by step to the surface of the powder tire in the thickness direction in the molding mold and maintaining it for a certain time, and when the displacement deformation δ in the thickness direction of the powder tire does not exceed 0.001 mm within 30 minutes, stop applying pressure to obtain a sample that reaches a saturated surface dry state;

[0010] Step 4: Take out the sample that has reached the saturated surface dry state, put the sample into a weighing box, and weigh the weight of the sample and the weighing box before drying (m) and the weight of the sample and the weighing box after drying (m) respectively. s , calculate the saturated surface dry water absorption of the sample according to formula (a):

[0011]

[0012] Among them, δ is the displacement deformation of the powder tire in the thickness direction, mm; m is the weight of the weighing box and the sample before drying, g; m s is the weight of the weighing box and the sample after drying, g; w is the saturated surface dry moisture content of the sample, %.

[0013] As a preferred embodiment of the present invention, the pore size of the standard sieve through which the test sample is sieved in step 1 is 0.075 mm.

[0014] As a preferred embodiment of the present invention, considering the plastic limit of the micropowder liquid, different loading methods are performed according to the plasticity index (classification). For silt samples with IP < 7, the initial load in step 3 is 50 kPa, which is directly increased to 600 kPa for loading; for clay samples with IP ≥ 7, the initial load in step 3 is 50 kPa, which is gradually increased from 200 kPa, 400 kPa to 600 kPa for loading.

[0015] As a preferred embodiment of the present invention, the drying temperature in step 4 is 105° C. to 110° C. An electric oven or other energy oven capable of maintaining a temperature of 105° C. to 110° C. may be used.

[0016] As a preferred embodiment of the present invention, in step 2, before the test sample is loaded into the molding die, a silicone grease layer or a polytetrafluoroethylene layer is coated on the surface of the molding die in contact with the test sample.

[0017] When pressure is applied step by step in step 3, the loading area is 30cm 2 , loading height is 20mm.

[0018] The test environment temperature in step 1 is consistent with the test water temperature, preferably 20±5°C.

[0019] The present application provides an inactive micro-powder saturated dry surface sample forming and testing integrated machine, which is characterized by comprising:

[0020] A base, the base comprising a base and a hollow supporting boss arranged at one end of the base, each side of the supporting boss being provided with a hollow structure and / or a limiting groove communicating with the inner cavity;

[0021] The sample forming mechanism is arranged on the base, and comprises a water storage box for collecting water squeezed out during the pressing of the sample to be tested, and a forming mold detachably arranged in the water storage box for filling the sample to be tested;

[0022] A pressure mechanism, disposed on the base, for applying pressure to the molding die to press the test sample in the molding die into shape; and

[0023] The displacement detection mechanism is arranged on the pressure mechanism and is used to detect the displacement deformation of the sample pressed in the forming die.

[0024] As a preferred embodiment of the present invention, the base includes a pedestal and a hollow supporting boss arranged at one end of the pedestal, and each side surface of the supporting boss is provided with a hollow structure and / or a limiting groove connected to the inner cavity.

[0025] As a preferred embodiment of the present invention, the molding die comprises, from bottom to top, a lower guard ring, a ring knife, an upper guard ring, an upper permeable stone, and a pressure cover. The lower guard ring, the ring knife, and the upper guard ring are partially overlapped to form a molding cavity that runs through from top to bottom for accommodating the sample to be tested. The lower permeable stone is arranged at the inner bottom of the lower guard ring; a pressure transmission column arranged along the central axis direction of the pressure cover is provided in the center of the pressure cover, and a steel ball is movably embedded in the top of the pressure transmission column.

[0026] As a preferred embodiment of the present invention, the upper permeable stone and the lower permeable stone are both made of alumina or corrosion-resistant metal materials.

[0027] As a preferred embodiment of the present invention, the diameter of the upper permeable stone is smaller than the inner diameter of the ring cutter.

[0028] As a preferred embodiment of the present invention, the diameter of the upper permeable stone is 0.2 to 0.5 mm smaller than the inner diameter of the ring cutter.

[0029] As a preferred embodiment of the present invention, the inner diameter of the ring cutter is 61.8 mm and the height is 20 mm.

[0030] As a preferred embodiment of the present invention, the ring cutter should have a certain rigidity, and a silicone grease layer or a polytetrafluoroethylene layer is preferably coated on the surface of the molding die in contact with the sample to be tested.

[0031] As a preferred embodiment of the present invention, the water storage box includes a box body which is arranged on a supporting boss and has an opening at the top, and a push-type elastic self-locking mechanism arranged in the box body for adjusting the vertical height of the forming mold. The push-type elastic self-locking mechanism includes a hook top plate, a buckle arranged at the bottom of the hook top plate, a pull rod arranged at the lower part of the buckle, a spring arranged at the bottom of the buckle, and a bottom box arranged at the bottom of the box body. A special-shaped limiting groove is provided on the side of the bottom box, and a protrusion is provided on the pull rod. The protrusion is inserted into the special-shaped limiting groove and is reliably limited by the special-shaped limiting groove, so as to realize the adjustment of the position of the hook top plate in the vertical direction.

[0032] As a preferred embodiment of the present invention, the push-type elastic self-locking mechanism has a first locking state and a second locking state. In the first locking state, the top plate of the hook fits the upper edge of the bottom box; in the second locking state, the top plate of the hook is flush with the upper edge of the box body.

[0033] As a preferred embodiment of the present invention, the special-shaped limiting groove is a special-shaped fold line groove, including a first inclined limiting groove, a second inclined limiting groove and a third inclined limiting groove connected in sequence, the bottom end of the first inclined limiting groove is the first position, the connection between the first inclined limiting groove and the second inclined limiting groove is the second position, the connection between the second inclined limiting groove and the third inclined limiting groove is the third position, and the top of the third inclined limiting groove is the fourth position; when the protrusion moves to the second position, the top plate of the pull hook is in contact with the bottom box of the box body, and when the protrusion moves to the fourth position, the top plate of the pull hook is flush with the top edge of the box body.

[0034] As a preferred embodiment of the present invention, the first position and the third position are consistent in vertical height, the vertical heights of the fourth position, the second position and the first position gradually decrease, and the projections of the first position, the second position, the third position and the fourth position on the same horizontal plane do not overlap and are arranged in sequence from small to large or from large to small according to the position number.

[0035] As a preferred embodiment of the present invention, the pressure mechanism includes an unequal-arm lever, a pressure frame and a pressure-transmitting piston, the unequal-arm lever passes through the supporting boss and is pivotally connected to the supporting boss through a pivot shaft, the short arm end of the unequal-arm lever is provided with a balance hammer, the long arm end of the unequal-arm lever is hung with a weight plate through a suspension rod, and weights are placed in the weight plate; the pressure frame is an inverted U-shape, and the two ends of the pressure frame are connected to the pivot shaft; the pressure-transmitting piston is slidably arranged on the top of the pressure frame, the top end of the pressure-transmitting piston is in contact and connected with the measuring end of the displacement detection mechanism, and the bottom end of the pressure-transmitting piston is rollingly matched with the steel ball on the top of the forming mold.

[0036] As a preferred embodiment of the present invention, the displacement detection mechanism includes a micrometer stand arranged on the pressure frame and a micrometer arranged on the micrometer stand, and the measuring end of the micrometer is connected to the top end of the pressure transmitting piston through a chuck, and is used to detect the displacement deformation of the sample pressed in the molding die.

[0037] As a preferred embodiment of the present invention, the micrometer is a displacement sensor with a measuring range of 10 mm and a minimum graduation of 0.001 mm.

[0038] As a preferred embodiment of the present invention, the micrometer stand comprises a vertical rod, a horizontal rod and a joint knob, the vertical rod is mounted on the pressure frame, and the vertical rod is connected to the horizontal rod via a joint knob.

[0039] As a preferred embodiment of the present invention, the measuring device has a measuring range of 200g and a sensitivity of no more than 0.01g.

[0040] The working process of the present invention is as follows:

[0041] When laying out, the top plate of the draw hook is pressed, and the buckle drives the pull rod to move downward. Since the limiting protrusion is stuck in the vertical limiting groove, the buckle can be prevented from always moving down in a vertical state. Due to the limitation of the special-shaped limiting groove, the protrusion of the pull rod moves from the second position along the second inclined limiting groove to the third position, and the pressure is released. At this time, the buckle drives the pull rod to move up and reset under the action of the spring, and the protrusion of the pull rod moves from the third position along the third inclined limiting groove to the fourth position until the protrusion is restricted by the special-shaped limiting groove and stops moving. The hook top plate is flush with the upper edge of the box body, so the operator can easily take and place the sample. After the operation is completed, press the hook top plate again to apply downward pressure to the hook top plate, and the buckle drives the pull rod to move downward. At this time, the protrusion of the pull rod moves from the fourth position along the third inclined limit groove to the second position, and finally to the first position. Stop pressing, and the buckle drives the pull rod to move up and reset under the action of the spring. The protrusion of the pull rod moves from the first position along the first inclined limit groove to the second position, completing the conversion from the second locking state to the first locking state.

[0042] When pressurizing, different loading methods can be used according to the plasticity index (classification) of the sample. The long arm end of the unequal-arm lever is connected to the weight plate through a hanger, and the weight is added to ensure the balance of the unequal-arm lever. The short arm end of the unequal-arm lever is connected to a balance hammer, and the balance hammer is rotated to adjust its distance in the length direction of the unequal-arm lever to balance the unequal-arm lever and keep it horizontal. When adjusting the force, the pressurizing frame can rotate synchronously with the pivot shaft, so that the pressurizing frame can swing with the pivot shaft as the center, thereby pulling the pressure transmission piston to move, applying pressure to the sample in the molding mold, and the micrometer measures the displacement deformation.

[0043] Compared with the prior art, the beneficial effects of this application are:

[0044] 1. A new test method is proposed, which can directly perform saturated surface dryness test on powders with a particle size not exceeding 0.075 mm, making up for the lack of direct testing of such powders by existing devices and methods.

[0045] 2. The non-active micropowder saturated surface dry sample forming and testing all-in-one machine of the present invention can realize the integration of four steps of sample forming, drying process, judging the saturated surface dry state, and calculating the saturated surface dry water absorption rate. In the sample forming process, by measuring the displacement deformation of the sample, it is possible to judge in real time whether the sand sample has reached the saturated surface dry state. This not only eliminates the need for the repeated operation of the two steps of drying and judging the saturated surface dry state, but also solves the problem that the judgment of the saturated surface dry state depends on the operating experience of the experimenter, thereby significantly improving the accuracy and convenience of the measurement.

[0046] 3. The inactive micropowder saturated surface dry water absorption test method proposed in the present invention can convert the detection of micropowder (<0.075mm) saturated surface dry water absorption rate into a stable value of sample displacement deformation under continuous pressure load, and then accurately calculate the micropowder saturated surface dry water absorption rate through relevant tests and calculations. It not only effectively avoids the influence of human factors on the test results, but also is convenient and fast, has strong operability and high reliability of results.

[0047] 4. The present invention adds a push-type elastic self-locking mechanism. After pressing, the top plate of the hook can be flush with the water storage box, and instruments such as ring knives, samples, and permeable stones can be placed directly to avoid the water storage box being too deep and the sample cannot be placed horizontally in the center. Pressing again can restore the initial state, realizing two different stroke controls, simple operation, and the overall effect is simple and elegant. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 This is a flowchart of the inactive micropowder saturated surface dryness test method of the present application.

[0049] Figure 2 This is a schematic diagram of the structure of the inactive micropowder saturated dry surface sample forming and testing all-in-one machine for the present application.

[0050] Figure 3 This is a schematic diagram of the structure of the molding die of this application.

[0051] Figure 4 This is an exploded view of the molding die of this application.

[0052] Figure 5 A three-dimensional view of the push-type elastic self-locking mechanism of the present application;

[0053] Figure 6 It is a structural diagram of the push-type elastic self-locking mechanism of the present invention (the buckle is disengaged from the top plate of the draw hook, and the arrow represents the movement direction of the component);

[0054] Figure 7 It is a structural diagram of the push-type elastic self-locking mechanism of the present invention (the buckle and the top plate of the draw hook are in a buckled state);

[0055] Figure 8 It is a schematic diagram of the cooperation between the special-shaped limiting groove and the pull rod of the push-type elastic self-locking mechanism of the present invention.

[0056] Fig. 9 It is a structural diagram of the pull rod of the push-type elastic self-locking mechanism of the present invention.

[0057] Fig.10 yes Figure 8 A partial enlarged view of .

[0058] Fig.11 It is one of the structural schematic diagrams of the buckle of the press-type elastic self-locking mechanism of the present invention.

[0059] Fig.12 This is the second structural schematic diagram of the buckle of the press-type elastic self-locking mechanism of the present invention.

[0060] In the accompanying description:

[0061] 1-base; 11-base; 12-support boss;

[0062] 2-sample forming mechanism; 21-water storage box; 211-box body; 212-pressing elastic self-locking mechanism; 2121-hook top plate; 2122-buckle; 2123-pull rod; 2124-spring; 2125-bottom box; 2126-special-shaped limiting groove; 2127-protrusion; 2128-first inclined limiting groove; 2129-second inclined limiting groove; 2120-third inclined limiting groove; 2131-limiting protrusion; 2132-limiting column; 2133-connecting shaft; 2134-pivoting through hole; 2135-adjusting hole;

[0063] 22-forming mold; 221-lower guard ring; 222-ring knife; 223-upper guard ring; 224-upper permeable stone; 225-pressure cover; 226-lower permeable stone; 227-pressure transmission column; 228-steel ball;

[0064] 3-pressure mechanism; 31-unequal arm lever; 32-pressure frame; 33-pressure transmission piston; 34-weight; 35-pivot shaft; 36-suspender rod; 37-weight plate; 38-balance hammer;

[0065] 4-displacement detection mechanism; 41-micrometer stand; 42-micrometer; 411-vertical pole; 412-crossbar; 413-joint knob;

[0066] 5-Test specimen. DETAILED DESCRIPTION

[0067] The following describes the implementation of the present application through specific examples, and those skilled in the art can easily understand other advantages and effects of the present application from the contents disclosed in this specification. The present application can also be implemented or applied through other different specific implementations, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present application.

[0068] It should be noted that the process equipment or devices not specifically specified in the following embodiments are all conventional equipment or devices in the art.

[0069] In addition, it should be understood that one or more method steps mentioned in this application do not exclude the existence of other method steps before or after the combination step or the insertion of other method steps between these explicitly mentioned steps, unless otherwise specified; it should also be understood that the combination connection relationship between one or more devices / apparatuses mentioned in this application does not exclude the existence of other devices / apparatuses before or after the combination device / apparatus or the insertion of other devices / apparatuses between these two explicitly mentioned devices / apparatuses, unless otherwise specified. Moreover, unless otherwise specified, the numbering of each method step is only a convenient tool for identifying each method step, and is not intended to limit the order of arrangement of each method step or the scope of implementation of this application. Changes or adjustments in their relative relationships shall also be regarded as the scope of implementation of this application without substantial changes in the technical content.

[0070] The embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be understood as limiting the present application.

[0071] In the description of the present application, it should be understood that the terms "upper", "lower", "left", "right", "inner", "outer", "axial", "circumferential", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. In addition, features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present application, unless otherwise specified, "multiple" means two or more.

[0072] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0073] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0074] The present application is further described below in conjunction with specific embodiments, but the protection scope of the present application is not limited thereto.

[0075] Example 1

[0076] The inactive micropowder saturated surface dryness test method of the present invention comprises the following steps:

[0077] Step 1: sieve the sample to be tested and soak it until it is saturated with water to obtain a wet powder;

[0078] Specifically, proceed as follows:

[0079] Sieve the sample to be tested (i.e., fine powder) through a 0.075 mm standard sieve to remove the portion larger than 0.075 mm. Weigh about 500 g of each portion and place them in a shallow dish or other suitable container.

[0080] Place the sample to be tested in a clean container and add sufficient clean water to completely submerge the micropowder, but do not use any detergent, dispersant or surfactant.

[0081] Use a stirring rod to fully stir the powder to clean the surface of the powder, but do not break the powder or splash it out of the water.

[0082] Let it stand for 24 hours. On the premise of ensuring that the powder does not dissipate, use a rubber-tipped dropper to carefully absorb the accumulated water in the clean container to obtain wet powder for later use.

[0083] Step 2: Fill the wet powder into a forming mold to make a powder tire;

[0084] Specifically, proceed as follows:

[0085] Press the top plate of the pull hook. In the initial state, the top plate of the pull hook fits with the bottom box. Under the pressing action, the buckle moves downward in the vertical direction, and at the same time drives the pull rod to move to the third position C along the second inclined limit groove of the special-shaped limit groove on the side of the bottom box. After releasing the hand, the pull rod moves upward along the third inclined limit groove of the special-shaped limit groove under the action of the spring, and finally moves to the fourth position. At this time, the top plate of the pull hook rises to be flush with the water storage box.

[0086] Take out the ring knife, wipe it with a soft cloth to keep the inner wall smooth, apply a layer of silicone grease or polytetrafluoroethylene, and lay multiple layers of filter paper on the bottom.

[0087] Use a spoon to load the fully soaked micro powder into the circular knife in two layers. The first layer should be loaded to about two-thirds of the height of the circular knife, and a knife should be used to cut 5 times in two perpendicular directions. Then load the second layer of micro powder, loading it to about 20mm above the circular knife, and a knife should be used to cut 5 times in two perpendicular directions.

[0088] Place a scraping ruler at an angle of approximately 90° (but slightly inclined in the scraping direction) on one end of the ring cutter, then slowly move toward the other end along the diameter of the ring cutter with a horizontal sawing motion to scrape off the powder that exceeds the ring cutter, and cover the surface with a layer of filter paper.

[0089] Wipe the outer wall of the ring cutter clean and place the cutter blade downward into the lower guard ring.

[0090] Place the lower permeable stone and multiple layers of filter paper on the top plate of the hook. Place the lower retaining ring and the sample into the water storage box, and continue to cover the sample with filter paper and upper permeable stone.

[0091] Pressing the top plate of the pull hook indirectly applies force to the buckle, which moves downward in the vertical direction, and at the same time drives the protrusion of the pull rod along the side of the bottom box to move from the fourth position along the upper contour edge of the special-shaped limiting groove, through the second position, and then to the first position. After releasing the hand, the pull rod moves up again along the special-shaped limiting groove to the second position, and the buckle and the top plate of the pull hook move up synchronously, so that the protrusion is stuck in the special-shaped limiting groove to achieve positioning and locking.

[0092] Lower the upper guard ring, the upper permeable stone and the pressure cover in sequence to make all parts in close contact and maintain stability to complete the filling of the wet powder.

[0093] Step 3, applying pressure step by step to the surface of the powder tire in the thickness direction in the molding mold and maintaining it for a certain time, and when the displacement deformation δ in the thickness direction of the powder tire does not exceed 0.001 mm within 30 minutes, stop applying pressure to obtain a sample that reaches a saturated surface dry state;

[0094] The specific operations are as follows:

[0095] Place the forming mold in the center of the pressure frame, close the pressure transmission piston and the crossbeam, so that the bottom end of the pressure transmission piston and the steel ball on the top end of the pressure cover are rollingly matched;

[0096] Pre-apply 1.0 kPa pressure to the molding die to make the various parts of the test instrument in close contact, adjust the position of the dial indicator, and adjust the reading of the dial indicator to zero.

[0097] Remove the preload and immediately load the first level of load. Avoid impact and shaking when adding weights. Record the time while adding weights. The load levels are generally specified as 50kPa, 200kPa, 400kPa and 600kPa. Consider the softness and hardness of the micro powder and perform different loading methods according to the plasticity index (classification).

[0098] For silt with IP<7, the initial load is 50kPa and the load is directly increased to 600kPa.

[0099] For clay with IP ≥ 7, the initial load is 50 kPa, and the load is gradually increased from 200 kPa, 400 kPa to 600 kPa.

[0100] The compression time under each level of load is set at 60 minutes, and the height change of the sample is measured and recorded as the stability standard. When the deformation of the millimeter display does not exceed 0.001mm in the last 30 minutes, the saturated surface dry state is allowed to be used as a relative stability standard. If the standard deformation is not met after more than 30 minutes, the pressure is continuously applied with a load of 600kPa until the deformation stability test is completed.

[0101] Step 4: Take out the sample that has reached the saturated surface dry state, put the sample into a weighing box, and weigh the weight of the sample and the weighing box before drying (m) and the weight of the sample and the weighing box after drying (m) respectively. s , calculate the saturated surface dry water absorption of the sample according to formula (a):

[0102]

[0103] Among them, δ is the displacement deformation of the powder tire in the thickness direction, mm; m is the weight of the weighing box and the sample before drying, g; m s is the weight of the weighing box and the sample after drying, g; w is the saturated surface dry moisture content of the sample, %.

[0104] The specific operations are as follows:

[0105] After the test, dismantle the instrument and carefully take out the complete sample.

[0106] Take a representative sample (15g-30g) and put it into a weighing box with a lid. Close the lid immediately and weigh the mass m to an accuracy of 0.01g.

[0107] Open the box cover, place the sample together with the weighing box into the oven, and dry them at a constant temperature of 105-110℃. The drying time shall not be less than 8h.

[0108] Take out the dried sample and weighing box and put them into the dryer to cool (usually 0.5 to 1 hour). After cooling, cover the box and weigh the mass m. s , accurate to 0.01g.

[0109] The saturated surface dry water absorption of the sample was calculated according to formula (a). The test results are shown in Table 1.

[0110] Example 2

[0111] The present application provides an inactive micro-powder saturated dry surface sample forming and testing all-in-one machine, comprising:

[0112] A base 1, the base 1 comprising a base 11 and a hollow supporting boss 12 arranged at one end of the base 11, each side of the supporting boss 12 being provided with a hollow structure and / or a limiting groove communicating with an inner cavity;

[0113] The sample forming mechanism 2 is arranged on the base 1, and includes a water storage box 21 for collecting water squeezed out during the pressing of the sample to be tested, and a forming mold 22 detachably arranged in the water storage box 21 for filling the sample to be tested;

[0114] A pressure mechanism 3 is disposed on the base 1 and is used to apply pressure to the molding die 22 to press the test sample in the molding die 22 into shape; and

[0115] The displacement detection mechanism 4 is arranged on the pressure mechanism 3 and is used to detect the displacement deformation of the sample pressed in the molding die 22 .

[0116] In some embodiments of the present invention, the base 1 includes a pedestal 11 and a hollow supporting boss 12 disposed at one end of the pedestal 11, and each side of the supporting boss 12 is provided with a hollow structure and / or a limiting groove connected to the inner cavity.

[0117] In some embodiments of the present invention, the molding mold 22 includes, from bottom to top, a lower guard ring 221, a ring knife 222, an upper guard ring 223, an upper permeable stone 224, and a pressure cover 225. The lower guard ring 221, the ring knife 222, and the upper guard ring 223 are partially overlapped to form a molding cavity that runs through from top to bottom for accommodating the sample to be tested. A lower permeable stone 226 is arranged at the inner bottom of the lower guard ring 221; a pressure transmission column 227 arranged along the central axis direction of the pressure cover 225 is provided in the center of the pressure cover 225, and a steel ball 228 is movably embedded in the top of the pressure transmission column 227.

[0118] In some embodiments of the present invention, the water storage box 21 includes a box body 211 which is arranged on the supporting boss 12 and has an opening at the top, and a push-type elastic self-locking mechanism 212 which is arranged in the box body 211 and is used to adjust the vertical height of the forming mold 22. The push-type elastic self-locking mechanism 212 includes a hook top plate 2121, a buckle 2122 arranged at the bottom of the hook top plate 2121, a pull rod 2123 arranged at the lower part of the buckle 2122, a spring 2124 arranged at the bottom of the buckle 2122, and a bottom box 2125 arranged at the bottom of the box body 211. The side of the bottom box 2125 is provided with a special-shaped limiting groove 2126, and the pull rod 2123 is provided with a protrusion 2127. The protrusion 2127 is inserted into the special-shaped limiting groove 2126 and is reliably limited by the special-shaped limiting groove 2126, so as to realize the adjustment of the position of the hook top plate 2121 in the vertical direction.

[0119] In some embodiments of the present invention, the special-shaped limiting groove 2126 is a special-shaped fold line groove, including a first inclined limiting groove 2128, a second inclined limiting groove 2129 and a third inclined limiting groove 2120 connected in sequence, the bottom end of the first inclined limiting groove 2128 is the first position A, the connection between the first inclined limiting groove 2128 and the second inclined limiting groove 2129 is the second position B, the connection between the second inclined limiting groove 2129 and the third inclined limiting groove 2120 is the third position C, and the top of the third inclined limiting groove 2120 is the fourth position D; when the protrusion 2127 moves to the second position, the top plate 2121 of the pull hook is fitted with the bottom box 2125 of the box body 211, and when the protrusion 2127 moves to the fourth position, the top plate 2121 of the pull hook is flush with the top edge of the box body 211.

[0120] In some embodiments of the present invention, the first position A and the third position C are consistent in vertical height, the fourth position D, the second position B, and the first position A are gradually reduced in vertical height, and the projections of the first position A, the second position B, the third position C, and the fourth position D on the same horizontal plane do not overlap and are arranged in sequence from small to large or from large to small according to the position number.

[0121] In some embodiments of the present invention, a limiting column 2132 is provided at the center of the inner bottom surface of the bottom box 2125 , and the spring 2124 is sleeved on the outside of the limiting column 2132 .

[0122] In some embodiments of the present invention, the base box 2125 is a cubic box with an opening on the top, and a special-shaped limiting groove 2126 is provided on one of the side panels of the base box 2125. A vertical limiting groove is provided on the inner wall of the side panel of the base box 2125 opposite to the special-shaped limiting groove 2126. A limiting protrusion 2131 is provided on the side of the buckle facing the vertical limiting groove, and the limiting protrusion 2131 is snapped into the vertical limiting groove to limit the movement trajectory of the buckle during the lifting process, thereby preventing the buckle and the pull rod from shaking in the horizontal direction during the lifting process.

[0123] In some embodiments of the present invention, a slot is provided at the upper portion of the buckle 2122 , the buckle 2122 is engaged with the hook at the bottom of the hook top plate 2121 , and a pivot through hole 2134 is provided at the middle portion of the buckle 2122 .

[0124] In some embodiments of the present invention, an adjustment hole 2135 for the entry and exit of the spring is provided at the lower portion of the buckle 2122 , and the adjustment hole 2135 is communicated with the inner cavity of the buckle 2122 .

[0125] In some embodiments of the present invention, the upper end of the pull rod 2123 is provided with a connecting shaft 2133 that can be inserted into the pivot through hole of the buckle, and the lower part of the pull rod 2123 is provided with a protrusion 2127 that can be inserted into the special-shaped limiting groove 2126. The push-type elastic self-locking mechanism 212 has a first locking state and a second locking state. In the first locking state, the protrusion 2127 is located at the second position B, at which time the top plate 2121 of the hook is in contact with the upper edge of the bottom box; in the second locking state, the protrusion 2127 is located at the fourth locking position, at which time the top plate 2121 of the hook is flush with the upper edge of the box body. The hook top plate 2121 is pressed, and the buckle 2122 drives the pull rod 2123 to move downward. Since the limiting protrusion 2131 is stuck in the vertical limiting groove, the buckle 2122 can be prevented from always maintaining a vertical state and moving down. Due to the limitation of the special-shaped limiting groove 2126, the protrusion 2127 of the pull rod 2123 moves from the second position B along the second inclined limiting groove 2129 to the third position C, and the pressure is released. At this time, the buckle drives the pull rod to move up and reset under the action of the spring, and the protrusion 2127 of the pull rod moves from the third position C along the third inclined limiting groove 2120 to the fourth position D until the protrusion 2127 is stopped by the special-shaped limiting groove 2126. The movement is restricted to stop. At this time, the top plate 2121 of the hook is flush with the upper edge of the box body, and the operator can easily take and place the sample. After the operation is completed, press the top plate 2121 of the hook again to apply downward pressure to the top plate 2121 of the hook, and the buckle drives the pull rod 2123 to move downward. At this time, the protrusion 2127 of the pull rod moves from the fourth position D along the third inclined limit groove 2120 to the second position, and finally to the first position. Stop pressing, and the buckle drives the pull rod to move up and reset under the action of the spring. The protrusion 2127 of the pull rod moves from the first position A along the first inclined limit groove to the second position B, completing the conversion from the second locking state to the first locking state.

[0126] In some embodiments of the present invention, the inner diameter of the ring cutter is 61.8 mm and the height is 20 mm.

[0127] In some embodiments of the present invention, the pressure mechanism 3 includes an unequal-arm lever 31, a pressure frame 32 and a pressure-transmitting piston 33. The unequal-arm lever 31 passes through the support boss 12 and is pivoted to the support boss 12 through a pivot shaft 35. The short arm end of the unequal-arm lever 31 is provided with a balance hammer 38, and the long arm end of the unequal-arm lever 31 is hung with a weight plate 37 through a suspension rod 36, and a weight 34 is placed in the weight plate 37; the pressure frame 32 is an inverted U shape, and the two ends of the pressure frame 32 are connected to the pivot shaft; the pressure-transmitting piston 33 is slidably arranged on the top of the pressure frame 32, the top end of the pressure-transmitting piston 33 is in contact and connected with the measuring end of the displacement detection mechanism 4, and the bottom end of the pressure-transmitting piston 33 is rollingly matched with the steel ball 228 at the top of the molding mold 22.

[0128] In some embodiments of the present invention, the displacement detection mechanism 4 includes a micrometer stand 41 arranged on the pressure frame 32 and a micrometer 42 arranged on the micrometer stand 41. The measuring end of the micrometer 42 is connected to the top end of the pressure transmitting piston 33 through a chuck, and is used to detect the displacement deformation of the sample pressed in the molding mold 22.

[0129] In some embodiments of the present invention, the micrometer stand 41 includes a vertical rod 411 , a horizontal rod 412 and a joint knob 413 . The vertical rod 411 is mounted on the pressure frame 32 , and the vertical rod 411 is connected to the horizontal rod 412 via a joint knob 413 .

[0130] Using the specific implementation steps of Example 1, put the three sand samples to be tested into a working environment with a temperature of (20±5)°C 1 day in advance. When the temperature is consistent with the room temperature, take 500g of the sample to be tested and stir it evenly. Soak in water and let it stand for 24 hours. Use a rubber-tipped dropper to carefully absorb the accumulated water for later use. Apply silicone grease to the inner wall of the ring cutter, lay filter paper on the bottom, load the micropowder into the ring cutter in two layers, and scrape the surface flat. Install the ring cutter into the guard ring, cover the filter paper and permeable stone, and install the pressure device. Pre-apply 1.0kPa pressure to ensure a close fit, install the micrometer and adjust it to zero. Select the appropriate loading method according to the plasticity index. Among them, the diabase powder Ip = 3.1 and the tuff powder Ip = 6.5 are both <7, which belong to silt. Select the initial load of 50kPa and increase it directly to 600kPa for loading. The basalt powder Ip = 8.7 > 7 belongs to clay. Select the initial load of 50kPa and gradually increase it from 200kPa, 400kPa to 600kPa for loading. Apply each level for 1h, record the deformation, remove the instrument after the reading stabilizes, take out the representative sample, and record the weight of the weighing box and the sample before drying (referred to as wet weight) m, the weight of the weighing box and the sample after drying and cooling (referred to as dry weight) m s , and then calculate the saturated surface dry water absorption (%) of the sample according to formula (a).

[0131] Table 1 Saturated surface dry water absorption of the samples tested by the test method of the present invention

[0132]

[0133]

[0134] It can be seen from the calculation results in Table 1 that the method of the present invention can be used to perform the inactive micropowder saturated surface dry test, and the test results of the present invention are similar, indicating that the inactive micropowder saturated surface dry test method proposed by the present invention can convert the detection work of the micropowder (<0.075mm) saturated surface dry water absorption rate into the displacement deformation of the sample under continuous pressure load. The stability is good and the test results are accurate. It not only effectively avoids the influence of human factors on the test results, but also is convenient and fast, has strong operability, and has high reliability of results.

[0135] The above examples are for the purpose of illustrating the embodiments disclosed in the present application and should not be construed as limiting the present application. In addition, the various modifications listed herein and the variations of methods and compositions in the invention are obvious to those skilled in the art without departing from the scope and spirit of the present application. Although the present application has been specifically described in conjunction with various specific preferred embodiments of the present application, it should be understood that the present application should not be limited to these specific embodiments. In fact, various modifications obvious to those skilled in the art as described above to obtain inventions should be included within the scope of the present application.

Claims

1. A method for testing the dryness of saturated surface of inactive micropowder, characterized in that: The following steps are involved: Step 1: sieve the sample to be tested and soak it until it is saturated with water to obtain a wet powder; Step 2: Fill the wet powder into a forming mold to make a powder tire; Step 3, applying pressure step by step to the surface of the powder tire in the thickness direction in the molding mold and maintaining it for a certain time, and when the displacement deformation δ in the thickness direction of the powder tire does not exceed 0.001 mm within 30 minutes, stop applying pressure to obtain a sample that reaches a saturated surface dry state; Step 4: Take out the sample that has reached the saturated surface dry state, and weigh the weight of the sample before drying m and the weight after drying m respectively. s , calculate the saturated surface dry water absorption of the sample according to formula (a): Among them, δ is the displacement deformation of the powder tire in the thickness direction, mm; m is the weight of the weighing box and the sample before drying, g; ms is the weight of the weighing box and the sample after drying, g; w is the saturated surface dry moisture content of the sample, %.

2. The inactive micropowder saturated surface dryness test method according to claim 1, characterized in that: The sieve hole diameter of the standard sieve through which the test sample is sieved in step 1 is 0.075 mm.

3. The inactive micropowder saturated surface dryness test method according to claim 1, characterized in that: For silt samples with IP < 7, the initial load applied in step 3 is 50 kPa, which is directly increased to 600 kPa; for clay samples with IP ≥ 7, the initial load applied in step 3 is 50 kPa, which is gradually increased from 200 kPa, 400 kPa to 600 kPa.

4. The inactive micropowder saturated surface dryness test method according to claim 1, characterized in that: In step 4, the drying temperature is 105°C to 110°C.

5. The inactive micropowder saturated surface dryness test method according to claim 1, characterized in that: Step 2: Before the test sample is loaded into the molding die, a silicone grease layer or a polytetrafluoroethylene layer is coated on the inner surface of the molding die that is in contact with the test sample.

6. The inactive micropowder saturated surface dryness test method according to claim 1, characterized in that: When pressure is applied step by step in step 3, the loading area is 30cm 2 , loading height is 20mm.

7. The inactive micropowder saturated surface dryness test method according to claim 1, characterized in that: The test environment temperature and test water temperature in step 1 are consistent.

8. An inactive micro-powder saturated surface dry sample forming and testing all-in-one machine constructed according to the inactive micro-powder saturated surface dry test method according to any one of claims 1 to 7, characterized in that: include: A base (1), the base (1) comprising a base (11) and a hollow supporting boss (12) arranged at one end of the base (11), each side of the supporting boss (12) being provided with a hollow structure and / or a limiting groove communicating with an inner cavity; A sample forming mechanism (2) is arranged on the base (1), comprising a water storage box (21) for collecting water squeezed out during the pressing of the sample to be tested, and a forming mold (22) detachably arranged in the water storage box (21) for filling the sample to be tested; A pressure mechanism (3) is arranged on the base (1) and is used to apply pressure to the molding die (22) so as to press the sample to be tested in the molding die (22) into shape; as well as The displacement detection mechanism (4) is arranged on the pressure-applying mechanism (3) and is used to detect the displacement deformation of the sample pressed and formed in the forming die (22).

9. The inactive micro-powder saturated dry surface sample forming and testing all-in-one machine according to claim 8, characterized in that: The molding die (22) comprises, from bottom to top, a lower guard ring (221), a ring knife (222), an upper guard ring (223), an upper permeable stone (224), and a pressure cover (225); the lower guard ring (221), the ring knife (222), and the upper guard ring (223) are partially overlapped to form a molding cavity that is through-through and used to accommodate a sample to be tested; the lower permeable stone (226) is arranged at the inner bottom of the lower guard ring (221); a pressure transmission column (227) arranged along the central axis direction of the pressure cover (225) is arranged at the center of the pressure cover (225); a steel ball (228) is movably embedded at the top of the pressure transmission column (227).

10. The inactive micro powder saturated surface dry sample forming and testing all-in-one machine according to claim 8, characterized in that: The water storage box (21) comprises a box body (211) which is arranged on a supporting boss (12) and has an open top, and a push-type elastic self-locking mechanism (212) which is arranged in the box body (211) and is used to adjust the vertical height of the forming mold (22). The push-type elastic self-locking mechanism (212) comprises a hook top plate (2121), a buckle (2122) arranged at the bottom of the hook top plate (2121), a pull rod (2123) arranged at the lower part of the buckle (2122), and a pull rod (2124) arranged at the lower part of the buckle (2124). A spring (2124) is provided at the bottom of the buckle (2122) and a bottom box (2125) is arranged at the bottom of the box body (211), the side of the bottom box (2125) is provided with a special-shaped limiting groove (2126), the pull rod (2123) is provided with a protrusion (2127), the protrusion (2127) is inserted into the special-shaped limiting groove (2126) and is reliably limited by the special-shaped limiting groove (2126), so as to realize the adjustment of the position of the pull hook top plate (2121) in the vertical direction.

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