JP7409874B2 - Concrete testing methods and equipment - Google Patents

Description

The present invention relates to a concrete testing method and apparatus suitable for measuring the viscosity of medium-flowing concrete.

Conventionally, in order to ensure concrete fillability under a variety of construction conditions, so-called "medium-flow concrete" (which requires compaction), which has fluidity intermediate between general slump range concrete and high-flow concrete, has been used. The application of "high fluidity concrete" is increasing. In this concrete as well, understanding the viscosity is very important from the viewpoint of material separation, pumpability evaluation, etc. Measuring the time taken to reach a flow of 500 mm in a slump flow test can also be considered as an indicator of viscosity, but this test involves visually observing the time to reach a circle with a diameter of 500 mm and measuring it with a stopwatch. In cases where the slump flow slightly exceeds 500 mm or is less than 500 mm, as in the case of fluidized concrete, measurement may be difficult. In addition, there are other methods such as a funnel test, but there are cases where the liquid does not flow down, and it may not be possible to obtain a numerical value that is an indicator of viscosity.

On the other hand, the L-shaped flow test is known as a test devised for quality control of concrete whose viscosity is high and the quality of workability cannot be judged only by slump. The L-shaped flow test is standardized in JCI-SQA1 (L-shaped flow test method (draft)) and JSCE-F514-2018 (L-shaped flow test method (draft) for high-flow concrete). In this L-shaped flow test, an L-shaped tester 3 having a vertical section 1 and a horizontal section 2 as shown in FIG. 7(1) is used. As shown in FIG. 7, after filling the vertical section 1 with a concrete sample, the partition gate 4 that separates the vertical section 1 and the horizontal section 2 is pulled up, and the passage time of a predetermined section in which the flow flows from the opening is measured. When the vertical part 1 stops, the amount of subsidence and the amount of movement to the tip are measured. The major difference between JCI-SQA1 and JSCE-F514 is that JCI-SQA1 requires that the sample be packed either without tamping in one layer (method A) or tamping in two layers 5 times each (method B). However, JSCE-F514 only describes the method without tamping, and JCI-SQA1 describes a method for measuring the initial velocity of L flow using a sensor (measurement is optional).

Compared to the slump flow test, the L-type flow test has less variation in measured values in terms of flow measurement and measurement of the time to reach 500 mm flow (JSCE-F516-2012) because the sample flows in only one direction. , it is thought that the characteristic is that there are few individual differences in measurement. However, simply measuring the value of the maximum L flow does not change the significance of the slump flow. In both standards, the dimensions of the L flow testing device are the same, but the length of the flow section is set to 755 mm (JCI-SQA1), which is a length that does not cause any inconvenience to the test. In both cases, the time taken to reach the L flow is measured, and a stopwatch is used to measure the passing time from the start to a point (L flow (mm)) at an arbitrary distance. The average flow velocity of the L flow is calculated by dividing the L flow by the time taken to reach the L flow, and the average flow velocity varies depending on the composition (preparation) of the materials used and the water binder ratio. However, as shown in the target value of the time to reach 500 mm flow for high-flow concrete shown in the Japan Society of Civil Engineers' high-flow concrete mixing design and construction guidelines [2012 edition], the time to reach L flow and the average flow velocity are No guideline for target values has been established. Against this background, the current situation is that the L-type flow test is not widely used.

It is said that the method for measuring the initial velocity of L flow using a sensor shown in JCI-SQA1 can be used as an index of the plastic viscosity of concrete. In this method, when the partition gate is pulled up and the concrete is flowing, the time it takes for the tip of the concrete to pass through points 50 mm and 100 mm from the opening is measured using an infrared or ultrasonic sensor, and the L Find the initial velocity of the flow. It is said that in this part, the pressure difference due to the concrete's own weight and the resistance force are balanced, resulting in flow close to a steady state, and the difference in velocity in this part can be easily understood as a difference in the plastic viscosity of the concrete. Since the time it takes to pass between 50mm and 100mm is short, it is difficult to measure with a stopwatch because it is prone to errors, so a non-contact sensor is used. Since the initial velocity of L flow is measured at a location close to the opening, it is thought that it can also be applied to medium-flowing concrete.

On the other hand, as conventional concrete testing methods using the L-shaped flow test, for example, Patent Documents 1 to 3 are known. In the methods disclosed in Patent Documents 1 to 3, a concrete sample is caused to flow down an inclined flow portion with an inclined angle, and the flowing velocity of the sample at that time is measured using a non-contact sensor. In the method of Patent Document 1, the mixture is adjusted or modified to avoid construction troubles depending on the viscosity of the concrete unloaded by a ready-mixed concrete truck. Generally, ready-mixed concrete trucks arrive continuously during pouring, so even if the viscosity is determined on-site, it takes a considerable amount of time to correct the mix, and even if corrections are made, they will not be reflected until several trucks later. You may end up with a concrete car and be unable to avoid trouble.

Japanese Patent Application Publication No. 2004-69363 JP2017-223490A JP 2019-117095 Publication

Edited by Japan Society of Civil Engineers, “Concrete Library No. 136, Mixture Design and Construction Guidelines for High-Flow Concrete [2012 Edition]”

Incidentally, the selection of concrete mix and the formulation of construction plans such as concrete pumping are always carried out at many construction sites. It would be advantageous if a mixture with an appropriate viscosity could be easily determined at the test mixing stage of mixture selection, since this would make it easier to formulate a construction plan for concrete pumping, etc. However, the test methods in Patent Documents 1 to 3 mentioned above are all based on the use of non-contact sensors, so they are difficult to obtain due to the complexity of obtaining non-contact sensors, creating jigs, and organizing data. There is a problem in that it is difficult to conduct tests on a regular basis. For this reason, there has been a desire for a versatile test method that can be easily implemented at any construction site and that can easily determine properties such as viscosity.

The present invention has been made in view of the above, and an object of the present invention is to provide a concrete testing method and apparatus that allow characteristics such as viscosity to be easily determined.

In order to solve the above-mentioned problems and achieve the purpose, the concrete testing method according to the present invention is a testing method for determining the viscosity of uncured concrete, which includes a container for storing a concrete sample. an opening provided on the side surface of the storage portion; and a ramp connected to the opening and having an inclined surface that goes downward as it moves away from the opening, and the inclination angle of the inclined surface from the horizontal can be changed; In an inclined L-shaped flow tester that is provided with a partition gate that is movable in the vertical direction with respect to the opening and that can open and close the opening, the step of filling the container with a sample and the step of pulling up the partition gate and filling the container with the sample. Flowing the sample down the ramp from the opening, measuring the transit time over a predetermined section set in advance on the ramp, and determining an index representing the relationship between the inclination angle of the ramp and the transit time; The present invention is characterized by comprising a step of evaluating the viscosity of the sample by applying the obtained index representing the relationship between the inclination angle and the transit time to the previously obtained relationship between the index and the viscosity.

In addition, another concrete testing method according to the present invention further includes the step of evaluating the pressure loss in the pipe by applying the evaluated viscosity to the relationship between the viscosity obtained in advance and the pressure loss in the pipe during concrete pumping. It is characterized by having.

Further, the concrete testing device according to the present invention is a testing device for determining the viscosity of uncured concrete, and includes a housing section for housing a concrete sample, and an opening provided on the side surface of the housing section. a ramp that connects to the opening and has a slope that goes downward as it moves away from the opening, and that can change the angle of inclination of the slope from horizontal; and a ramp that is movable in the vertical direction with respect to the opening. An inclined L-shaped flow tester is equipped with a partition gate that can open and close the opening, and the partition gate is pulled up to allow the sample filled in the container to flow down from the opening onto the ramp, and the sample is set in advance on the ramp. a measuring means for measuring the passing time of a predetermined section, a calculating means for calculating an index representing the relationship between the inclination angle of the slope and the passing time, and a calculation means for calculating the relationship between the obtained inclination angle and the passing time based on the relationship between the index and viscosity obtained in advance. The method is characterized by comprising an evaluation means for evaluating the viscosity of the sample by applying an index representing the relationship.

Further, in the above-mentioned invention, in another concrete testing device according to the present invention, the evaluation means evaluates the pressure loss in the pipe by applying the evaluated viscosity to the relationship between the viscosity and the pressure loss in the pipe during concrete pumping, which is obtained in advance. It is characterized by

According to the concrete testing method according to the present invention, the method is a testing method for determining the viscosity of uncured concrete, and includes a housing section for housing a concrete sample, and an opening provided on the side surface of the housing section. a ramp that connects to the opening and has a slope that goes downward as it moves away from the opening, and that can change the angle of inclination of the slope from horizontal; and a ramp that is movable in the vertical direction with respect to the opening. In an inclined L-shaped flow tester equipped with a partition gate that can open and close an opening, a step of filling a container with a sample, and a step of pulling up the partition gate and causing the sample in the container to flow down the ramp from the opening. , a step of measuring the passing time of a predetermined section set in advance on the slope, a step of grasping an index representing the relationship between the slope angle of the slope and the passing time, and a step of grasping the relationship between the index obtained in advance and the viscosity. Since the method includes the step of evaluating the viscosity of the sample by applying an index representing the relationship between the inclination angle and the transit time, it is possible to easily understand the viscosity.

Further, according to another concrete testing method according to the present invention, the method further includes the step of evaluating the pressure loss in the pipe by applying the evaluated viscosity to the relationship between the viscosity and the pressure loss in the pipe during concrete pumping, which is obtained in advance. This has the effect of making it possible to easily understand the pressure loss inside the pipe during concrete pumping.

Further, according to the concrete testing device according to the present invention, the testing device is for determining the viscosity of uncured concrete, and includes a housing section for housing a concrete sample, and a housing section provided on the side surface of the housing section. It has an opening and a slope connected to the opening that goes downward as it moves away from the opening, the slope can change the angle of inclination from the horizontal, and it can be moved up and down with respect to the opening. An inclined L-shaped flow tester is provided with a partition gate that can open and close the opening, and the partition gate is pulled up to allow the sample filled in the container to flow down from the opening onto the ramp. A measuring means for measuring the passing time in a predetermined section set in advance, a calculating means for obtaining an index representing the relationship between the inclination angle of the slope and the passing time, and a calculating means for calculating the relationship between the index obtained in advance and the viscosity. Since the present invention includes an evaluation means for evaluating the viscosity of a sample by applying an index representing a time relationship, the viscosity can be easily grasped.

Further, according to another concrete testing device according to the present invention, the evaluation means evaluates the pressure loss in the pipe by applying the evaluated viscosity to the relationship between the viscosity and the pressure loss in the pipe during concrete pumping, which is obtained in advance. This has the effect of making it possible to easily understand the pressure loss inside the pipe during concrete pumping.

FIG. 1 is a perspective view showing an embodiment of an inclined L-shaped flow tester used in the concrete testing method according to the present invention. FIG. 2 is a diagram showing the test situation. FIG. 3 is a table diagram showing the mix of concrete. FIG. 4 is a diagram showing the relationship between the inclination angle and the 30 cm passing time. FIG. 5 is a diagram showing the relationship between the absolute value of the coefficient of X of the regression line for the 30 cm transit time and the plastic viscosity. FIG. 6 is a diagram showing the relationship between plastic viscosity and pressure loss in a pipe. FIG. 7(1) is a diagram showing a conventional L-type flow tester, and FIG. 7(2) is a photographic diagram showing an L-type flow test situation. FIG. 8 is a diagram showing the relationship between fluidity and the necessity of compaction (source: Non-Patent Document 1).

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a concrete testing method and apparatus according to the present invention will be described in detail below based on the drawings. Note that the present invention is not limited to this embodiment.

First, concrete and the like to which the present invention is applied will be explained. The concrete targeted by the present invention has a slump of 21 cm or more and a slump flow of about 55 cm or less. In the diagram of the relationship between fluidity and the necessity of compaction in Figure 8 (source: Non-Patent Document 1), the concrete targeted by the present invention is "high fluidity concrete that requires compaction" in the center of the diagram. This is the part where it is. According to the present invention, the viscosity of concrete that cannot be measured by a funnel test or a 50 cm flow time is evaluated. An example of an index representing viscosity is plastic viscosity. The applicable range of plastic viscosity targeted by the present invention is 10 to 100 Pa·s, preferably 10 to 60 Pa·s. For concrete with a slump of 21 cm or less, the slump value is important in evaluating workability. In addition, for concrete that has self-filling properties, slump flow, 50 cm flow time, funnel flow time, etc. are used to evaluate workability.

(Concrete test method)
Next, an inclined L-shaped flow tester used in the concrete testing method according to the present embodiment will be explained.
As shown in FIG. 1, this inclined L-shaped flow tester 10 includes a storage section 12 for storing a concrete sample, an opening 14 provided on the lower side of the front side of the storage section 12, and an opening. 14, a partition gate 18, and a pedestal 20. The accommodating portion 12 is a square cylindrical container with an open top and a flat bottom. The opening 14 is a rectangular opening, and its lower edge is continuous with the lower surface of the accommodating part 12. The ramp 16 is a rectangular cross-section passageway having an inclined surface 16A that goes downward as it moves away from the opening 14. The top surface of the ramp 16 is open. The ramp 16 and the accommodating portion 12 are installed on a pedestal 20 with a flat top surface, and by operating a not-illustrated inclination mechanism provided on the legs of the pedestal 20, the inclination angle θ from the horizontal of the slanted surface 16A is adjusted. Can be changed. The partition gate 18 is provided so as to be movable in the vertical direction with respect to the opening 14, and can open and close the opening 14.

Next, a concrete testing method using the above-mentioned inclined L-shaped flow tester 10 will be explained. First, a concrete sample is placed in the container 12, and the tilting mechanism of the pedestal 20 is operated to set the tilt angle θ of the ramp 16 to a predetermined angle. Subsequently, as shown in FIG. 2, the partition gate 18 is pulled up to allow the sample in the container 12 to flow down from the opening 14 onto the ramp 16. Using a stopwatch, measure the time taken for the tip of the sample to pass through a predetermined section. Although the measurement section in this embodiment is set at a distance of 30 cm from the opening 14 (L flow (mm)), the present invention is not limited to this, and distances other than this are set as the measurement section. May be set.

A plurality of measurements are performed for one concrete mixture while changing the condition of the inclination angle θ of the inclined surface 16A. As a result, a relationship diagram between the inclination angle θ and the transit time is created, and an index representing the relationship between the inclination angle θ and the transit time is grasped from the relationship diagram. Although the inclination angle θ in this embodiment is set to three levels: θ=0° (horizontal), 10°, and 15°, the present invention is not limited to this, and can be applied to other combinations of angles. May be set. As an index representing the relationship between the inclination angle θ and the transit time, for example, the slope (absolute value) of the regression line obtained from the inclination angle θ and the transit time can be used.

On the other hand, before the actual measurement, the relationship between the above index and viscosity (for example, plastic viscosity) is obtained in advance. The viscosity of the sample is evaluated by applying to this relationship the index representing the relationship between the inclination angle θ and the transit time, which was determined by the above measurement. According to the present embodiment, the necessary equipment is the inclined L-shaped flow tester 10 and a stopwatch, and there is no need for non-contact type sensors as in conventional Patent Documents 1 to 3. Therefore, according to the present embodiment, after the index is determined through the above measurement, the viscosity can be easily determined.

(Measurement example)
Next, a measurement example conducted to verify the effects of the present invention will be described.
Figure 3 shows the concrete mix used in the test. As the admixture, a common polycarboxylic acid-based high performance AE water reducing agent was used in all formulations.

The measurement results of the transit time at the 30 cm point using the above-mentioned inclined L-shaped flow tester 10 are shown in FIG. In this figure, each plot, regression line, and correlation coefficient R for combination numbers 1 to 4 are shown. In the equation of the regression line, y is the transit time (sec) and x is the inclination angle (degrees). In all formulations, the passage time becomes shorter as the inclination angle increases, but the tendency differs depending on the formulation. Those with a small amount of cement and those with a large water-cement ratio tended to have a short transit time at the 30 cm point, and although there were three levels of inclination angle, a good correlation was observed in linear regression analysis for all three levels. This regression line is considered to be related to the magnitude of viscosity, and it is considered that the larger the slope, which is the coefficient of x in FIG. 4, is, the larger the viscosity is. That is, it can be said that the viscosity is lower as the formulation number 1 increases, and the viscosity is relatively higher in the formulation numbers 3 and 4.

FIG. 5 shows the relationship between the absolute value of the slope, which is the coefficient of x of the regression line in FIG. 4, and the plastic viscosity measured with a rotary vane viscometer for the formulations Nos. 1 to 4. This figure shows each plot of the plastic viscosity of formulation numbers 1 to 4, the regression line, and the correlation coefficient R. In the equation of the regression line, y is the plastic viscosity (Pa·s), and x is the absolute value of the slope which is the coefficient of x of the regression line in FIG. Using the relationship shown in FIG. 5, it is possible to roughly understand the plastic viscosity from the absolute value of the slope, which is the coefficient of x of the regression line.

In this way, when the inclination angle θ of the inclined L-shaped flow tester 10 is set to three levels: horizontal (θ = 0°), 10°, and 15°, the results of the transit time at the 30 cm point are organized as shown in Figure 4. By doing so, it is possible to grasp the relative magnitude of viscosity between the formulations. Further, from the absolute value of the gradient, which is the coefficient of x of the regression line at that time, it is possible to grasp the approximate value of the plastic viscosity using the relationship shown in FIG. By utilizing these viscosity trends and plastic viscosity, it can be used for mix design of medium-flow concrete, evaluation of filling properties, etc., evaluation of pumpability (estimation of K value), etc.

For example, the relationship between plastic viscosity and pipe pressure loss during concrete pumping as shown in FIG. 6 may be obtained in advance, and the plastic viscosity may be applied to this relationship to estimate or evaluate the pipe pressure loss during pumping. In this way, it is possible to easily understand the pressure loss in the pipe during pumping, and it is possible to study the pumping properties (formulate a pumping plan). In addition, in said FIG. 6, each plot of the discharge amount 20 and 30 (m ^<3> /h) at the time of pressure feeding, the regression line, and the correlation coefficient R are shown. In the equation of the regression line, y is the pressure loss in the pipe per meter (Mpa/m), and x is the plastic viscosity (Pa·s).

(Concrete testing equipment)
Next, an embodiment of a concrete testing device according to the present invention will be described.
As shown in FIG. 1, the concrete testing apparatus according to the present embodiment includes the above-mentioned inclined L-shaped flow tester 10, a stopwatch as a measuring means (not shown), a calculating means, and an evaluation means. The stopwatch, calculation means, and evaluation means are all not shown in FIG.

The stopwatch is for measuring the passage time of a predetermined section set in advance on the ramp 16 by pulling up the partition gate 18 and allowing the sample filled in the container 12 to flow down the ramp 16 from the opening 14. It is.

The calculating means is for obtaining an index representing the relationship between the inclination angle θ of the inclined surface 16A and the transit time. The calculation means can be configured using, for example, an arithmetic device such as a computer.

The evaluation means is for evaluating the viscosity of the sample by applying the obtained index representing the relationship between the angle of inclination and the transit time to the relationship between the index and viscosity obtained in advance. The evaluation means may have a function of evaluating the pressure loss in the pipe by applying the evaluated viscosity to the relationship between the viscosity and the pressure loss in the pipe during concrete pumping, which has been obtained in advance. The evaluation means can be configured using, for example, an arithmetic device such as a computer.

If the above configuration is used, the viscosity can be easily understood as in the embodiment of the concrete testing method described above. That is, using the calculation means, the results of the transit time at the 30 cm point when the inclination angle θ of the inclined L-shaped flow tester 10 is set to three levels: horizontal (θ = 0°), 10°, and 15° are shown in FIG. By arranging it as follows, it is possible to understand the relative viscosity between the formulations. Further, by using the evaluation means, it is possible to grasp the approximate value of the plastic viscosity from the absolute value of the slope, which is the coefficient of x of the regression line at that time, using the relationship shown in FIG. By utilizing these viscosity trends and plastic viscosity, it can be used for mix design of medium-flow concrete, evaluation of filling properties, etc., evaluation of pumpability (estimation of K value), etc. For example, by using the relationship shown in FIG. 6, it is possible to easily understand the pressure loss in the pipe during pressure feeding.

As explained above, the concrete testing method according to the present invention is a testing method for determining the viscosity of uncured concrete, and includes a housing section for housing a concrete sample, and a side surface of the housing section. an opening provided in the opening, a ramp that connects to the opening and has a slope that goes downward as it moves away from the opening, and that can change the angle of inclination of the slope from horizontal; In an inclined L-shaped flow tester equipped with a partition gate that is movable in the direction and that can open and close the opening, filling the container with a sample, and lifting the partition gate to remove the sample in the container from the opening. A step of letting the water flow down the ramp, a step of measuring the passage time over a predetermined section set in advance on the ramp, a step of understanding an index representing the relationship between the inclination angle of the slope and the passage time, and a step of measuring the index obtained in advance and the viscosity. The method includes a step of evaluating the viscosity of the sample by applying an index representing the determined relationship between the tilt angle and the transit time to the relationship, so that the viscosity can be easily determined.

Further, according to another concrete testing method according to the present invention, the method further includes the step of evaluating the pressure loss in the pipe by applying the evaluated viscosity to the relationship between the viscosity and the pressure loss in the pipe during concrete pumping, which is obtained in advance. It is possible to easily understand the pressure loss inside the pipe during concrete pumping.

Further, according to the concrete testing device according to the present invention, the testing device is for determining the viscosity of uncured concrete, and includes a housing section for housing a concrete sample, and a housing section provided on the side surface of the housing section. It has an opening and a slope connected to the opening that goes downward as it moves away from the opening, the slope can change the angle of inclination from the horizontal, and it can be moved up and down with respect to the opening. An inclined L-shaped flow tester is provided with a partition gate that can open and close the opening, and the partition gate is pulled up to allow the sample filled in the container to flow down from the opening onto the ramp. A measuring means for measuring the passing time in a predetermined section set in advance, a calculating means for obtaining an index representing the relationship between the inclination angle of the slope and the passing time, and a calculating means for calculating the relationship between the index obtained in advance and the viscosity. Since it has an evaluation means for evaluating the viscosity of the sample by applying an index representing the relationship with time, the viscosity can be easily understood.

Further, according to another concrete testing device according to the present invention, the evaluation means evaluates the pressure loss in the pipe by applying the evaluated viscosity to the relationship between the viscosity and the pressure loss in the pipe during concrete pumping, which is obtained in advance. It is possible to easily understand the pressure loss inside the pipe during concrete pumping.

As described above, the concrete testing method and apparatus according to the present invention are useful for measuring the viscosity of medium-flow concrete, and are particularly suitable for simply understanding the viscosity.

10 Inclined L-shaped flow tester 12 Storage part 14 Opening part 16 Ramp way 16A Inclined surface 18 Partition gate 20 Pedestal

Claims (4)

A test method for determining the viscosity of uncured concrete,
an accommodating part for accommodating a concrete sample; an opening provided on a side surface of the accommodating part; and an inclined surface that connects to the opening and goes downward as you move away from the opening ; In the inclined L-shaped flow tester, the inclination L-shaped flow tester is provided with a ramp that can change the inclination angle from the horizontal , and a partition gate that is provided to be movable in the vertical direction with respect to the opening and that can open and close the opening. filling the sample into the chamber;
pulling up the partition gate to cause the sample in the container to flow down from the opening onto the ramp;
using a stopwatch to measure the time taken for the tip of the sample to pass through a predetermined section set in advance on the ramp;
determining the absolute value of the slope of the regression line obtained from the inclination angle and the passing time as an index representing the relationship between the inclination angle of the inclined surface and the passing time ;
A concrete testing method comprising the step of evaluating the viscosity of the sample by applying the obtained absolute value of the gradient to the relationship between the absolute value of the gradient and viscosity obtained in advance . 2. The concrete testing method according to claim 1, further comprising the step of applying the evaluated viscosity of the sample to a pre-obtained relationship between viscosity and pressure loss in the pipe during concrete pumping to evaluate the pressure loss in the pipe. . A test device for determining the viscosity of uncured concrete,
an accommodating part for accommodating a concrete sample; an opening provided on a side surface of the accommodating part; and an inclined surface that connects to the opening and goes downward as you move away from the opening ; an inclined L-shaped flow tester comprising a ramp whose inclination angle from the horizontal can be changed; and a partition gate that is movable up and down with respect to the opening and that can open and close the opening;
Pulling up the partition gate, causing the sample filled in the storage part to flow down the ramp from the opening, and measuring the passage time for the tip of the sample to pass through a predetermined section set in advance on the ramp. a measuring means consisting of a stopwatch ,
Calculating means for calculating the absolute value of the slope of the regression line obtained from the inclination angle and the passing time as an index representing the relationship between the inclination angle of the inclined surface and the passing time ;
A concrete testing device comprising evaluation means for evaluating the viscosity of the sample by applying the absolute value of the slope obtained by the calculation means to the relationship between the absolute value of the slope and viscosity obtained in advance . The concrete test according to claim 3, wherein the evaluation means evaluates the pressure loss in the pipe by applying the evaluated viscosity of the sample to the relationship between the viscosity and the pressure loss in the pipe during concrete pumping, which has been obtained in advance. Device.

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