JPH07109398B2 - Method and apparatus for testing workability, breathing or pressure dehydration of raw mortars - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention contains raw mortars (raw mortars include raw mortar and powdered material such as concrete, and liquids, and are used for civil engineering and building materials. Test method and apparatus for workability, breathing or pressure dewatering of curable materials).

[Conventional technology]

The physical property test of raw mortars is a very important test for determining the quality of the mortar.

Conventionally, there is a workability test as a physical property test method for raw mortars, and there are various methods such as a slump test specified in JIS A1101, a flow test specified in ASTM C124, and a penetration test specified in old IN 1048. There is.

Among them, the slump test has the simplest test method and has been used frequently since ancient times as a relatively reliable physical property test.

[Problems to be Solved by the Invention]

However, in the above method which has been conventionally performed to know the physical property values of raw mortars, the fluidity and workability of raw mortars can be measured but the properties such as breathing cannot be measured. Therefore, a breathing test, a pressure dehydration test, etc. must be performed separately, which requires extra labor and time.

It is an object of the present invention to provide a test method and an apparatus therefor which can easily and easily know the physical property values of raw mortar.

[Means for Solving the Problems]

The method of the present invention for solving the above-mentioned problems is to put a specimen of raw mortar molded into a predetermined shape in a net-like container, and repeatedly submerge and pull it into a liquid under a certain regularity, With repetition, the number of repetitions until the cement component and aggregate smaller than the mesh of the mesh container do not remain, or until the time when the weight change of the mesh container containing the sample is substantially eliminated. The workability, breathing, or pressure dehydration of the raw mortar is judged based on the number of repetitions.

Test method.

Further, the apparatus of the present invention, a liquid tank for containing a liquid, a net-like container that contains a specimen of raw mortar molded into a predetermined shape, and that permeates a cement component and a small-diameter aggregate, and this net-like container A liquid immersion drive means for repeating liquid immersion and pulling up in a liquid under a certain regularity, and a weight measuring means for measuring the weight of the sample and the mesh container provided in the suspension part of the sample and the mesh container. Further, based on the number of repetitions until the weight change detected by the weight measuring means is substantially eliminated, the workability, breathing or pressure dehydration of the raw mortar is determined. It is characterized by that.

[Action]

When a test specimen in which raw mortars are molded into a predetermined shape is placed in a reticulated container and submerged and pulled up repeatedly according to a certain regularity, for example, in the case of mortar, the cement content and the aggregate with a small diameter are in the reticulated container. It permeates through the mesh and disperses in the liquid or sinks to the bottom of the liquid tank, and the large aggregate remains in the mesh container.

It was clarified that the permeation rate from this mesh, that is, the change in the weight of the sample with respect to the number of repetitions of liquid immersion and pulling up showed a difference depending on the blending of the raw mortar, as shown in the test results described later.

Therefore, the physical properties can be determined by focusing on the amount of permeation with respect to the number of repetitions from the mesh container. Further, such a permeation rate is not only an indicator of the fluidity and workability of mortars, but also an indicator of the degree of breathing and pressure dehydration. There is an advantage that all physical properties can be judged.

[Specific configuration of the invention]

 The present invention will be described in more detail below.

FIG. 1 shows a physical property testing apparatus according to the present invention.
Is a net-shaped container that accommodates the specimen M formed in a predetermined shape, and can be submerged in and pulled up from the water tank 9 with the specimen M accommodated therein. For this submersion and pulling up, a driving gear 6 is fixed to the output shaft of the rotary drive motor 5, and a rotating plate 7 that is driven by the driving gear 6 and has a meshing portion is rotatably provided by a rotating shaft 7a. ing.

A crank 8 is integrated with the rotary shaft 7a. The other end of the crank 8 and the reticulated container 1 are connected by a guide wire 3 passing through a rotating shackle 2 attached to the tip of a support arm member 4 fixed to a pedestal 10.

In the device configured as described above, when the crank 8 rotates as the rotary motor 5 rotates, the crank 8 rotates.
The reticulated container 1 is submerged and pulled up by a crank mechanism that passes through the proximal point and the distal point.

Thereby, the permeation rate of the constituent material of the specimen M into water is tested.

In the above example, submersion and pulling up are performed by the rotary drive motor 5, but may be performed manually.

In addition, the measurement of the number of strokes of liquid immersion and pulling up,
Although it may be visually observed, a mechanism for automatically counting according to the number of rotations of the rotary plate 7 may be attached (not shown).

The mesh container 1 is, for example, a cylindrical container having a diameter of 20 cm and a height of 20 cm, and a steel container having a mesh of 3 mm. The material selected is one that does not deform when immersed in liquid. Also, container dimensions,
The mesh size can be changed depending on the particle size of the aggregate, the size of the raw mortar specimen, and the like. In addition, when the fluidity of the specimen is large, the bottom of the container may be plate-shaped instead of net-like and blind.

Next, the test piece conforms to JIS dimensions, for example, a diameter of 5 cm x
The height is 10 cm or the diameter is 10 cm and the height is 20 cm, or a conical shape may be used instead of the above-mentioned cylindrical shape, but an appropriate dimension is selected. As a general rule, the test piece is molded with a mold and immediately after demolding, the test piece is put into the mesh container 1 and the test is started. You may start the test.

As for the range of vertical movement of the reticulated container 1, the test starts with the bottom surface of the reticulated container 1 being located near the water surface, and then the reticulated container 1 is submerged until it contacts the water surface, and the bottom surface of the reticulated container 1 is pulled up to the position near the water surface. Can be

The cycle of the vertical stroke of the mesh container 1 is, for example, 20
Although the number of times per minute can be set, this cycle can be accelerated or delayed as long as the water surface is not disturbed. The point is that it is desirable to perform the same stroke and cycle.

The end of the physical property test is determined when the cement component of the raw mortar and the aggregate smaller than the mesh of the mesh container do not remain in the mesh container 1 (visual observation), or for pulling the guide wire 3 in the middle part in advance. By attaching the load cell 11 and measuring the weight of the mesh container 1 containing the sample M, the time when the weight change does not occur, the time when the weight change becomes minute, or the weight limit value is set in advance. It can be done by a method of putting it. As the above-mentioned weight limit value, if the gradient of the weight change is substantially constant in the course of reaching the time when the weight change does not substantially occur, the time when the weight change does not substantially occur can be predicted. Therefore, the time when the slope becomes almost constant is the weight limit value.

It is preferable to measure the weight when the mesh container 1 is completely exposed from water and reaches a static value. This is because if the measurement is performed in water or during the pulling process, the weight of the water adhered to the specimen and the load due to the acceleration associated with the pulling become erroneous loads.

〔Example〕

 Hereinafter, the effects of the present invention will be clarified by examples.

A cylindrical steel container having a diameter of 20 cm, a height of 20 cm, and a mesh of 3 mm is used as the mesh container 1, and the cycle of the vertical stroke of this mesh container 1 is set to 20 times / minute, and the submersion is performed until the upper surface of the mesh container 1 comes into contact with the water surface. The bottom of the mesh container 1 was repeatedly pulled up to a position 5 cm above the water surface.

The specimen had a diameter of 5 cm and a height of 10 cm, Kinugawa sand was used as the sand, and Portland ordinary cement was used as the type of cement. This sample was molded with a mold, immediately after demolding, put in the mesh container 1 to start the test.

The determination of the end of the physical property value test was made when the cement content and aggregate smaller than the mesh of the net-like container of the raw mortar did not remain visually in the net-like container 1.

The test was conducted when the cement sand ratio (C / S) and the mixing method were changed. The results obtained by the above test are shown in Table 1.

In Table 1, the number of times is 1 cycle of submersion and pulling up.
It is counted as the number of times, and the number of times until the cement component smaller than the mesh and the aggregate do not remain in the mesh container is shown. Hereinafter, this is called the number of repetitions.

As can be seen from Table 1, (1) It can be seen that the composition with a C / S of 1/4 has a greater number of repetitions than the composition with a C / S of 1/5, and the bonding strength between cement and fine aggregate is stronger.

(2) Regarding W / C, the amount of primary water and secondary water is appropriate, but the number of repetitions is large, and conversely, the ratio of primary water and secondary water is appropriate depending on the number of repetitions. Can judge.

(3) In double mixing and single mixing, it can be seen that double mixing is superior as a mixing method because the number of repetitions is larger.

Next, in Table 1, FIG. 2 shows the weight change in the case of double mixing in which C / S is 1/5, W / C is 25% primary water, and 60% secondary water. The vertical axis represents the weight of the sample and the horizontal axis represents the number of repetitions, and the weight of the sample is plotted every 5 repetitions. As is clear from FIG. 2, the change in the weight of the test piece was not repeated 35 times, and only the aggregate having a particle size larger than the mesh remained in the mesh container 1.

In addition, FIG. 3 shows a load set in the middle of the guide wire 3.
11 is installed and the signal is plotter processed. Since the curve obtained by connecting the reading points P of the total weight of the reticulated container 1 and the sample M to each other is the same as the weight change curve shown in FIG. 2, a sufficient test can be performed even if the weight is measured using the tension load cell. It turns out that the result is obtained.

Next, the correlation between the test result and the flow test result according to the present invention will be described.

The test was conducted in two cases where the cement sand ratio was 1/4 and 1/5. The number of samples was 26 in each case, and the regression line as shown below was obtained from the test results by the least squares method. In the formula, Y represents the number of repetitions of the test result according to the present invention, and X represents the flow value. Further, γ indicates a correlation coefficient.

When the cement sand ratio is 1/4, Y = 346−2.3X (γ = −0.56) When the cement sand ratio is 1/5, Y = 245−1.6X (γ = −0.54) Therefore, the number of repetitions Y is inversely proportional to the flow value X, and it is found that the test result according to the present invention and the flow test result have a correlation.

Furthermore, the correlation between the test results according to the present invention and the results of the pressure dehydration test will be described. The pressure dehydration test is based on API
According to the standard, it was performed by a filtration tester "KS-1701" manufactured by Tesco Co., Ltd. for a stable liquid control test.

The test was conducted in two cases where the cement sand ratio was 1/4 and 1/5. The number of samples was 26 in each case, and the regression line as shown below was obtained from the test results by the least squares method. In the formula, Y represents the number of repetitions of the test result according to the present invention, and X represents the pressure dehydration value. Further, γ indicates a correlation coefficient.

When the cement sand ratio is 1/4, Y = 192−3.2X (γ = −0.83) When the cement sand ratio is 1/5, Y = 151−2.5X (γ = −0.83) Therefore, the number of repetitions Y is inversely proportional to the pressure dehydration value X, and it is found that the test result according to the present invention and the pressure dehydration test result have a correlation.

It has also been found that the test results according to the present invention and the breathing test results are similarly correlated.

Although the above example is an example of mortar, it has been found that the present invention can be similarly applied to concrete and bentonite-based hardening materials.

〔The invention's effect〕

The present invention has the following effects based on the test method and test results described above.

According to the test method of the present invention, not only the workability of raw mortars such as fluidity and workability but also the physical properties of breathing and pressure dehydration can be known at the same time.

Further, as a specific application of the method of the present invention, after determining an appropriate mixing / kneading method at a certain site, the test is performed to set the number of repetitions, and at any time during construction, a sample is sampled and the test is repeated to determine the number of repetitions. It can be used for the purpose of checking and determining whether proper construction is performed.

[Brief description of drawings]

FIG. 1 is a diagram of a test apparatus showing one embodiment of the present invention, FIG. 2 is a transition diagram of changes in the weight of a specimen with the number of repetitions according to the test of the present invention, and FIG. 3 is a test of the present invention using a tensile load cell. 5 is a change diagram of the weight change of the test piece according to FIG. 1 ... mesh container, 3 ... guide wire, 5 ... rotary drive motor, 7 ... rotating plate, 8 ... crank, 9 ... water tank

Claims (2)

[Claims] 1. A specimen of raw mortar molded into a predetermined shape is placed in a net-like container, which is repeatedly submerged and pulled up in a liquid under a certain regularity. And the number of repetitions until the time when aggregates smaller than the mesh of the mesh container do not remain, or based on the number of repetitions until the weight change of the mesh container containing the sample is substantially eliminated, A test method for workability, breathing or pressure dehydration of raw mortars, which comprises determining workability, breathing or pressure dehydration of raw mortars. 2. A liquid tank for containing a liquid, a mesh container for containing a specimen of raw mortar molded into a predetermined shape, and a cement component and an aggregate having a small diameter, and this mesh container A liquid immersion drive means for repeating liquid immersion and pulling up in a liquid under regularity, and a weight measuring means for measuring the weight of the sample and the mesh container provided in the hanging portion of the sample and the mesh container, And, based on the number of repetitions until the time when the weight change detected by the weight measuring means has substantially disappeared, workability, breathing or pressure dehydration of raw mortars is determined. Equipment for workability, breathing or pressure dehydration of raw mortars.